name-rev: refactor logic to see if a new candidate is a better name
[gitweb.git] / http.c
diff --git a/http.c b/http.c
index 1108ab4a3101fb4768cad420ccfdb52d87890a18..96d84bbed3f66153cc3d817f2b342dc5d1600574 100644 (file)
--- a/http.c
+++ b/http.c
@@ -1,8 +1,32 @@
+#include "git-compat-util.h"
 #include "http.h"
+#include "pack.h"
+#include "sideband.h"
+#include "run-command.h"
+#include "url.h"
+#include "urlmatch.h"
+#include "credential.h"
+#include "version.h"
+#include "pkt-line.h"
+#include "gettext.h"
+#include "transport.h"
+
+static struct trace_key trace_curl = TRACE_KEY_INIT(CURL);
+#if LIBCURL_VERSION_NUM >= 0x070a08
+long int git_curl_ipresolve = CURL_IPRESOLVE_WHATEVER;
+#else
+long int git_curl_ipresolve;
+#endif
+int active_requests;
+int http_is_verbose;
+size_t http_post_buffer = 16 * LARGE_PACKET_MAX;
 
-int data_received;
-int active_requests = 0;
+#if LIBCURL_VERSION_NUM >= 0x070a06
+#define LIBCURL_CAN_HANDLE_AUTH_ANY
+#endif
 
+static int min_curl_sessions = 1;
+static int curl_session_count;
 #ifdef USE_CURL_MULTI
 static int max_requests = -1;
 static CURLM *curlm;
@@ -10,27 +34,116 @@ static CURLM *curlm;
 #ifndef NO_CURL_EASY_DUPHANDLE
 static CURL *curl_default;
 #endif
+
+#define PREV_BUF_SIZE 4096
+
 char curl_errorstr[CURL_ERROR_SIZE];
 
 static int curl_ssl_verify = -1;
-static const char *ssl_cert = NULL;
-#if LIBCURL_VERSION_NUM >= 0x070902
-static const char *ssl_key = NULL;
+static int curl_ssl_try;
+static const char *ssl_cert;
+static const char *ssl_cipherlist;
+static const char *ssl_version;
+static struct {
+       const char *name;
+       long ssl_version;
+} sslversions[] = {
+       { "sslv2", CURL_SSLVERSION_SSLv2 },
+       { "sslv3", CURL_SSLVERSION_SSLv3 },
+       { "tlsv1", CURL_SSLVERSION_TLSv1 },
+#if LIBCURL_VERSION_NUM >= 0x072200
+       { "tlsv1.0", CURL_SSLVERSION_TLSv1_0 },
+       { "tlsv1.1", CURL_SSLVERSION_TLSv1_1 },
+       { "tlsv1.2", CURL_SSLVERSION_TLSv1_2 },
+#endif
+};
+#if LIBCURL_VERSION_NUM >= 0x070903
+static const char *ssl_key;
 #endif
 #if LIBCURL_VERSION_NUM >= 0x070908
-static const char *ssl_capath = NULL;
+static const char *ssl_capath;
+#endif
+#if LIBCURL_VERSION_NUM >= 0x072c00
+static const char *ssl_pinnedkey;
 #endif
-static const char *ssl_cainfo = NULL;
+static const char *ssl_cainfo;
 static long curl_low_speed_limit = -1;
 static long curl_low_speed_time = -1;
-static int curl_ftp_no_epsv = 0;
-static char *curl_http_proxy = NULL;
+static int curl_ftp_no_epsv;
+static const char *curl_http_proxy;
+static const char *curl_no_proxy;
+static const char *http_proxy_authmethod;
+static struct {
+       const char *name;
+       long curlauth_param;
+} proxy_authmethods[] = {
+       { "basic", CURLAUTH_BASIC },
+       { "digest", CURLAUTH_DIGEST },
+       { "negotiate", CURLAUTH_GSSNEGOTIATE },
+       { "ntlm", CURLAUTH_NTLM },
+#ifdef LIBCURL_CAN_HANDLE_AUTH_ANY
+       { "anyauth", CURLAUTH_ANY },
+#endif
+       /*
+        * CURLAUTH_DIGEST_IE has no corresponding command-line option in
+        * curl(1) and is not included in CURLAUTH_ANY, so we leave it out
+        * here, too
+        */
+};
+#if LIBCURL_VERSION_NUM >= 0x071600
+static const char *curl_deleg;
+static struct {
+       const char *name;
+       long curl_deleg_param;
+} curl_deleg_levels[] = {
+       { "none", CURLGSSAPI_DELEGATION_NONE },
+       { "policy", CURLGSSAPI_DELEGATION_POLICY_FLAG },
+       { "always", CURLGSSAPI_DELEGATION_FLAG },
+};
+#endif
+
+static struct credential proxy_auth = CREDENTIAL_INIT;
+static const char *curl_proxyuserpwd;
+static const char *curl_cookie_file;
+static int curl_save_cookies;
+struct credential http_auth = CREDENTIAL_INIT;
+static int http_proactive_auth;
+static const char *user_agent;
+static int curl_empty_auth = -1;
+
+enum http_follow_config http_follow_config = HTTP_FOLLOW_INITIAL;
+
+#if LIBCURL_VERSION_NUM >= 0x071700
+/* Use CURLOPT_KEYPASSWD as is */
+#elif LIBCURL_VERSION_NUM >= 0x070903
+#define CURLOPT_KEYPASSWD CURLOPT_SSLKEYPASSWD
+#else
+#define CURLOPT_KEYPASSWD CURLOPT_SSLCERTPASSWD
+#endif
+
+static struct credential cert_auth = CREDENTIAL_INIT;
+static int ssl_cert_password_required;
+#ifdef LIBCURL_CAN_HANDLE_AUTH_ANY
+static unsigned long http_auth_methods = CURLAUTH_ANY;
+static int http_auth_methods_restricted;
+/* Modes for which empty_auth cannot actually help us. */
+static unsigned long empty_auth_useless =
+       CURLAUTH_BASIC
+#ifdef CURLAUTH_DIGEST_IE
+       | CURLAUTH_DIGEST_IE
+#endif
+       | CURLAUTH_DIGEST;
+#endif
 
 static struct curl_slist *pragma_header;
+static struct curl_slist *no_pragma_header;
+static struct curl_slist *extra_http_headers;
 
-static struct active_request_slot *active_queue_head = NULL;
+static struct active_request_slot *active_queue_head;
 
-size_t fread_buffer(void *ptr, size_t eltsize, size_t nmemb, void *buffer_)
+static char *cached_accept_language;
+
+size_t fread_buffer(char *ptr, size_t eltsize, size_t nmemb, void *buffer_)
 {
        size_t size = eltsize * nmemb;
        struct buffer *buffer = buffer_;
@@ -43,23 +156,79 @@ size_t fread_buffer(void *ptr, size_t eltsize, size_t nmemb, void *buffer_)
        return size;
 }
 
-size_t fwrite_buffer(const void *ptr, size_t eltsize, size_t nmemb, void *buffer_)
+#ifndef NO_CURL_IOCTL
+curlioerr ioctl_buffer(CURL *handle, int cmd, void *clientp)
+{
+       struct buffer *buffer = clientp;
+
+       switch (cmd) {
+       case CURLIOCMD_NOP:
+               return CURLIOE_OK;
+
+       case CURLIOCMD_RESTARTREAD:
+               buffer->posn = 0;
+               return CURLIOE_OK;
+
+       default:
+               return CURLIOE_UNKNOWNCMD;
+       }
+}
+#endif
+
+size_t fwrite_buffer(char *ptr, size_t eltsize, size_t nmemb, void *buffer_)
 {
        size_t size = eltsize * nmemb;
        struct strbuf *buffer = buffer_;
 
        strbuf_add(buffer, ptr, size);
-       data_received++;
        return size;
 }
 
-size_t fwrite_null(const void *ptr, size_t eltsize, size_t nmemb, void *strbuf)
+size_t fwrite_null(char *ptr, size_t eltsize, size_t nmemb, void *strbuf)
 {
-       data_received++;
        return eltsize * nmemb;
 }
 
-static void finish_active_slot(struct active_request_slot *slot);
+static void closedown_active_slot(struct active_request_slot *slot)
+{
+       active_requests--;
+       slot->in_use = 0;
+}
+
+static void finish_active_slot(struct active_request_slot *slot)
+{
+       closedown_active_slot(slot);
+       curl_easy_getinfo(slot->curl, CURLINFO_HTTP_CODE, &slot->http_code);
+
+       if (slot->finished != NULL)
+               (*slot->finished) = 1;
+
+       /* Store slot results so they can be read after the slot is reused */
+       if (slot->results != NULL) {
+               slot->results->curl_result = slot->curl_result;
+               slot->results->http_code = slot->http_code;
+#if LIBCURL_VERSION_NUM >= 0x070a08
+               curl_easy_getinfo(slot->curl, CURLINFO_HTTPAUTH_AVAIL,
+                                 &slot->results->auth_avail);
+#else
+               slot->results->auth_avail = 0;
+#endif
+
+               curl_easy_getinfo(slot->curl, CURLINFO_HTTP_CONNECTCODE,
+                       &slot->results->http_connectcode);
+       }
+
+       /* Run callback if appropriate */
+       if (slot->callback_func != NULL)
+               slot->callback_func(slot->callback_data);
+}
+
+static void xmulti_remove_handle(struct active_request_slot *slot)
+{
+#ifdef USE_CURL_MULTI
+       curl_multi_remove_handle(curlm, slot->curl);
+#endif
+}
 
 #ifdef USE_CURL_MULTI
 static void process_curl_messages(void)
@@ -76,7 +245,7 @@ static void process_curl_messages(void)
                               slot->curl != curl_message->easy_handle)
                                slot = slot->next;
                        if (slot != NULL) {
-                               curl_multi_remove_handle(curlm, slot->curl);
+                               xmulti_remove_handle(slot);
                                slot->curl_result = curl_result;
                                finish_active_slot(slot);
                        } else {
@@ -94,53 +263,53 @@ static void process_curl_messages(void)
 static int http_options(const char *var, const char *value, void *cb)
 {
        if (!strcmp("http.sslverify", var)) {
-               if (curl_ssl_verify == -1) {
-                       curl_ssl_verify = git_config_bool(var, value);
-               }
-               return 0;
-       }
-
-       if (!strcmp("http.sslcert", var)) {
-               if (ssl_cert == NULL)
-                       return git_config_string(&ssl_cert, var, value);
-               return 0;
-       }
-#if LIBCURL_VERSION_NUM >= 0x070902
-       if (!strcmp("http.sslkey", var)) {
-               if (ssl_key == NULL)
-                       return git_config_string(&ssl_key, var, value);
+               curl_ssl_verify = git_config_bool(var, value);
                return 0;
        }
+       if (!strcmp("http.sslcipherlist", var))
+               return git_config_string(&ssl_cipherlist, var, value);
+       if (!strcmp("http.sslversion", var))
+               return git_config_string(&ssl_version, var, value);
+       if (!strcmp("http.sslcert", var))
+               return git_config_string(&ssl_cert, var, value);
+#if LIBCURL_VERSION_NUM >= 0x070903
+       if (!strcmp("http.sslkey", var))
+               return git_config_string(&ssl_key, var, value);
 #endif
 #if LIBCURL_VERSION_NUM >= 0x070908
-       if (!strcmp("http.sslcapath", var)) {
-               if (ssl_capath == NULL)
-                       return git_config_string(&ssl_capath, var, value);
+       if (!strcmp("http.sslcapath", var))
+               return git_config_pathname(&ssl_capath, var, value);
+#endif
+       if (!strcmp("http.sslcainfo", var))
+               return git_config_pathname(&ssl_cainfo, var, value);
+       if (!strcmp("http.sslcertpasswordprotected", var)) {
+               ssl_cert_password_required = git_config_bool(var, value);
+               return 0;
+       }
+       if (!strcmp("http.ssltry", var)) {
+               curl_ssl_try = git_config_bool(var, value);
                return 0;
        }
+       if (!strcmp("http.minsessions", var)) {
+               min_curl_sessions = git_config_int(var, value);
+#ifndef USE_CURL_MULTI
+               if (min_curl_sessions > 1)
+                       min_curl_sessions = 1;
 #endif
-       if (!strcmp("http.sslcainfo", var)) {
-               if (ssl_cainfo == NULL)
-                       return git_config_string(&ssl_cainfo, var, value);
                return 0;
        }
-
 #ifdef USE_CURL_MULTI
        if (!strcmp("http.maxrequests", var)) {
-               if (max_requests == -1)
-                       max_requests = git_config_int(var, value);
+               max_requests = git_config_int(var, value);
                return 0;
        }
 #endif
-
        if (!strcmp("http.lowspeedlimit", var)) {
-               if (curl_low_speed_limit == -1)
-                       curl_low_speed_limit = (long)git_config_int(var, value);
+               curl_low_speed_limit = (long)git_config_int(var, value);
                return 0;
        }
        if (!strcmp("http.lowspeedtime", var)) {
-               if (curl_low_speed_time == -1)
-                       curl_low_speed_time = (long)git_config_int(var, value);
+               curl_low_speed_time = (long)git_config_int(var, value);
                return 0;
        }
 
@@ -148,41 +317,462 @@ static int http_options(const char *var, const char *value, void *cb)
                curl_ftp_no_epsv = git_config_bool(var, value);
                return 0;
        }
-       if (!strcmp("http.proxy", var)) {
-               if (curl_http_proxy == NULL) {
-                       if (!value)
-                               return config_error_nonbool(var);
-                       curl_http_proxy = xstrdup(value);
+       if (!strcmp("http.proxy", var))
+               return git_config_string(&curl_http_proxy, var, value);
+
+       if (!strcmp("http.proxyauthmethod", var))
+               return git_config_string(&http_proxy_authmethod, var, value);
+
+       if (!strcmp("http.cookiefile", var))
+               return git_config_pathname(&curl_cookie_file, var, value);
+       if (!strcmp("http.savecookies", var)) {
+               curl_save_cookies = git_config_bool(var, value);
+               return 0;
+       }
+
+       if (!strcmp("http.postbuffer", var)) {
+               http_post_buffer = git_config_int(var, value);
+               if (http_post_buffer < LARGE_PACKET_MAX)
+                       http_post_buffer = LARGE_PACKET_MAX;
+               return 0;
+       }
+
+       if (!strcmp("http.useragent", var))
+               return git_config_string(&user_agent, var, value);
+
+       if (!strcmp("http.emptyauth", var)) {
+               if (value && !strcmp("auto", value))
+                       curl_empty_auth = -1;
+               else
+                       curl_empty_auth = git_config_bool(var, value);
+               return 0;
+       }
+
+       if (!strcmp("http.delegation", var)) {
+#if LIBCURL_VERSION_NUM >= 0x071600
+               return git_config_string(&curl_deleg, var, value);
+#else
+               warning(_("Delegation control is not supported with cURL < 7.22.0"));
+               return 0;
+#endif
+       }
+
+       if (!strcmp("http.pinnedpubkey", var)) {
+#if LIBCURL_VERSION_NUM >= 0x072c00
+               return git_config_pathname(&ssl_pinnedkey, var, value);
+#else
+               warning(_("Public key pinning not supported with cURL < 7.44.0"));
+               return 0;
+#endif
+       }
+
+       if (!strcmp("http.extraheader", var)) {
+               if (!value) {
+                       return config_error_nonbool(var);
+               } else if (!*value) {
+                       curl_slist_free_all(extra_http_headers);
+                       extra_http_headers = NULL;
+               } else {
+                       extra_http_headers =
+                               curl_slist_append(extra_http_headers, value);
                }
                return 0;
        }
 
+       if (!strcmp("http.followredirects", var)) {
+               if (value && !strcmp(value, "initial"))
+                       http_follow_config = HTTP_FOLLOW_INITIAL;
+               else if (git_config_bool(var, value))
+                       http_follow_config = HTTP_FOLLOW_ALWAYS;
+               else
+                       http_follow_config = HTTP_FOLLOW_NONE;
+               return 0;
+       }
+
        /* Fall back on the default ones */
        return git_default_config(var, value, cb);
 }
 
-static CURL* get_curl_handle(void)
+static int curl_empty_auth_enabled(void)
+{
+       if (curl_empty_auth >= 0)
+               return curl_empty_auth;
+
+#ifndef LIBCURL_CAN_HANDLE_AUTH_ANY
+       /*
+        * Our libcurl is too old to do AUTH_ANY in the first place;
+        * just default to turning the feature off.
+        */
+#else
+       /*
+        * In the automatic case, kick in the empty-auth
+        * hack as long as we would potentially try some
+        * method more exotic than "Basic" or "Digest".
+        *
+        * But only do this when this is our second or
+        * subsequent request, as by then we know what
+        * methods are available.
+        */
+       if (http_auth_methods_restricted &&
+           (http_auth_methods & ~empty_auth_useless))
+               return 1;
+#endif
+       return 0;
+}
+
+static void init_curl_http_auth(CURL *result)
+{
+       if (!http_auth.username || !*http_auth.username) {
+               if (curl_empty_auth_enabled())
+                       curl_easy_setopt(result, CURLOPT_USERPWD, ":");
+               return;
+       }
+
+       credential_fill(&http_auth);
+
+#if LIBCURL_VERSION_NUM >= 0x071301
+       curl_easy_setopt(result, CURLOPT_USERNAME, http_auth.username);
+       curl_easy_setopt(result, CURLOPT_PASSWORD, http_auth.password);
+#else
+       {
+               static struct strbuf up = STRBUF_INIT;
+               /*
+                * Note that we assume we only ever have a single set of
+                * credentials in a given program run, so we do not have
+                * to worry about updating this buffer, only setting its
+                * initial value.
+                */
+               if (!up.len)
+                       strbuf_addf(&up, "%s:%s",
+                               http_auth.username, http_auth.password);
+               curl_easy_setopt(result, CURLOPT_USERPWD, up.buf);
+       }
+#endif
+}
+
+/* *var must be free-able */
+static void var_override(const char **var, char *value)
+{
+       if (value) {
+               free((void *)*var);
+               *var = xstrdup(value);
+       }
+}
+
+static void set_proxyauth_name_password(CURL *result)
+{
+#if LIBCURL_VERSION_NUM >= 0x071301
+               curl_easy_setopt(result, CURLOPT_PROXYUSERNAME,
+                       proxy_auth.username);
+               curl_easy_setopt(result, CURLOPT_PROXYPASSWORD,
+                       proxy_auth.password);
+#else
+               struct strbuf s = STRBUF_INIT;
+
+               strbuf_addstr_urlencode(&s, proxy_auth.username, 1);
+               strbuf_addch(&s, ':');
+               strbuf_addstr_urlencode(&s, proxy_auth.password, 1);
+               curl_proxyuserpwd = strbuf_detach(&s, NULL);
+               curl_easy_setopt(result, CURLOPT_PROXYUSERPWD, curl_proxyuserpwd);
+#endif
+}
+
+static void init_curl_proxy_auth(CURL *result)
+{
+       if (proxy_auth.username) {
+               if (!proxy_auth.password)
+                       credential_fill(&proxy_auth);
+               set_proxyauth_name_password(result);
+       }
+
+       var_override(&http_proxy_authmethod, getenv("GIT_HTTP_PROXY_AUTHMETHOD"));
+
+#if LIBCURL_VERSION_NUM >= 0x070a07 /* CURLOPT_PROXYAUTH and CURLAUTH_ANY */
+       if (http_proxy_authmethod) {
+               int i;
+               for (i = 0; i < ARRAY_SIZE(proxy_authmethods); i++) {
+                       if (!strcmp(http_proxy_authmethod, proxy_authmethods[i].name)) {
+                               curl_easy_setopt(result, CURLOPT_PROXYAUTH,
+                                               proxy_authmethods[i].curlauth_param);
+                               break;
+                       }
+               }
+               if (i == ARRAY_SIZE(proxy_authmethods)) {
+                       warning("unsupported proxy authentication method %s: using anyauth",
+                                       http_proxy_authmethod);
+                       curl_easy_setopt(result, CURLOPT_PROXYAUTH, CURLAUTH_ANY);
+               }
+       }
+       else
+               curl_easy_setopt(result, CURLOPT_PROXYAUTH, CURLAUTH_ANY);
+#endif
+}
+
+static int has_cert_password(void)
+{
+       if (ssl_cert == NULL || ssl_cert_password_required != 1)
+               return 0;
+       if (!cert_auth.password) {
+               cert_auth.protocol = xstrdup("cert");
+               cert_auth.username = xstrdup("");
+               cert_auth.path = xstrdup(ssl_cert);
+               credential_fill(&cert_auth);
+       }
+       return 1;
+}
+
+#if LIBCURL_VERSION_NUM >= 0x071900
+static void set_curl_keepalive(CURL *c)
+{
+       curl_easy_setopt(c, CURLOPT_TCP_KEEPALIVE, 1);
+}
+
+#elif LIBCURL_VERSION_NUM >= 0x071000
+static int sockopt_callback(void *client, curl_socket_t fd, curlsocktype type)
+{
+       int ka = 1;
+       int rc;
+       socklen_t len = (socklen_t)sizeof(ka);
+
+       if (type != CURLSOCKTYPE_IPCXN)
+               return 0;
+
+       rc = setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, (void *)&ka, len);
+       if (rc < 0)
+               warning_errno("unable to set SO_KEEPALIVE on socket");
+
+       return 0; /* CURL_SOCKOPT_OK only exists since curl 7.21.5 */
+}
+
+static void set_curl_keepalive(CURL *c)
+{
+       curl_easy_setopt(c, CURLOPT_SOCKOPTFUNCTION, sockopt_callback);
+}
+
+#else
+static void set_curl_keepalive(CURL *c)
+{
+       /* not supported on older curl versions */
+}
+#endif
+
+static void redact_sensitive_header(struct strbuf *header)
+{
+       const char *sensitive_header;
+
+       if (skip_prefix(header->buf, "Authorization:", &sensitive_header) ||
+           skip_prefix(header->buf, "Proxy-Authorization:", &sensitive_header)) {
+               /* The first token is the type, which is OK to log */
+               while (isspace(*sensitive_header))
+                       sensitive_header++;
+               while (*sensitive_header && !isspace(*sensitive_header))
+                       sensitive_header++;
+               /* Everything else is opaque and possibly sensitive */
+               strbuf_setlen(header,  sensitive_header - header->buf);
+               strbuf_addstr(header, " <redacted>");
+       }
+}
+
+static void curl_dump_header(const char *text, unsigned char *ptr, size_t size, int hide_sensitive_header)
+{
+       struct strbuf out = STRBUF_INIT;
+       struct strbuf **headers, **header;
+
+       strbuf_addf(&out, "%s, %10.10ld bytes (0x%8.8lx)\n",
+               text, (long)size, (long)size);
+       trace_strbuf(&trace_curl, &out);
+       strbuf_reset(&out);
+       strbuf_add(&out, ptr, size);
+       headers = strbuf_split_max(&out, '\n', 0);
+
+       for (header = headers; *header; header++) {
+               if (hide_sensitive_header)
+                       redact_sensitive_header(*header);
+               strbuf_insert((*header), 0, text, strlen(text));
+               strbuf_insert((*header), strlen(text), ": ", 2);
+               strbuf_rtrim((*header));
+               strbuf_addch((*header), '\n');
+               trace_strbuf(&trace_curl, (*header));
+       }
+       strbuf_list_free(headers);
+       strbuf_release(&out);
+}
+
+static void curl_dump_data(const char *text, unsigned char *ptr, size_t size)
+{
+       size_t i;
+       struct strbuf out = STRBUF_INIT;
+       unsigned int width = 60;
+
+       strbuf_addf(&out, "%s, %10.10ld bytes (0x%8.8lx)\n",
+               text, (long)size, (long)size);
+       trace_strbuf(&trace_curl, &out);
+
+       for (i = 0; i < size; i += width) {
+               size_t w;
+
+               strbuf_reset(&out);
+               strbuf_addf(&out, "%s: ", text);
+               for (w = 0; (w < width) && (i + w < size); w++) {
+                       unsigned char ch = ptr[i + w];
+
+                       strbuf_addch(&out,
+                                      (ch >= 0x20) && (ch < 0x80)
+                                      ? ch : '.');
+               }
+               strbuf_addch(&out, '\n');
+               trace_strbuf(&trace_curl, &out);
+       }
+       strbuf_release(&out);
+}
+
+static int curl_trace(CURL *handle, curl_infotype type, char *data, size_t size, void *userp)
+{
+       const char *text;
+       enum { NO_FILTER = 0, DO_FILTER = 1 };
+
+       switch (type) {
+       case CURLINFO_TEXT:
+               trace_printf_key(&trace_curl, "== Info: %s", data);
+       default:                /* we ignore unknown types by default */
+               return 0;
+
+       case CURLINFO_HEADER_OUT:
+               text = "=> Send header";
+               curl_dump_header(text, (unsigned char *)data, size, DO_FILTER);
+               break;
+       case CURLINFO_DATA_OUT:
+               text = "=> Send data";
+               curl_dump_data(text, (unsigned char *)data, size);
+               break;
+       case CURLINFO_SSL_DATA_OUT:
+               text = "=> Send SSL data";
+               curl_dump_data(text, (unsigned char *)data, size);
+               break;
+       case CURLINFO_HEADER_IN:
+               text = "<= Recv header";
+               curl_dump_header(text, (unsigned char *)data, size, NO_FILTER);
+               break;
+       case CURLINFO_DATA_IN:
+               text = "<= Recv data";
+               curl_dump_data(text, (unsigned char *)data, size);
+               break;
+       case CURLINFO_SSL_DATA_IN:
+               text = "<= Recv SSL data";
+               curl_dump_data(text, (unsigned char *)data, size);
+               break;
+       }
+       return 0;
+}
+
+void setup_curl_trace(CURL *handle)
+{
+       if (!trace_want(&trace_curl))
+               return;
+       curl_easy_setopt(handle, CURLOPT_VERBOSE, 1L);
+       curl_easy_setopt(handle, CURLOPT_DEBUGFUNCTION, curl_trace);
+       curl_easy_setopt(handle, CURLOPT_DEBUGDATA, NULL);
+}
+
+static long get_curl_allowed_protocols(int from_user)
 {
-       CURL* result = curl_easy_init();
+       long allowed_protocols = 0;
+
+       if (is_transport_allowed("http", from_user))
+               allowed_protocols |= CURLPROTO_HTTP;
+       if (is_transport_allowed("https", from_user))
+               allowed_protocols |= CURLPROTO_HTTPS;
+       if (is_transport_allowed("ftp", from_user))
+               allowed_protocols |= CURLPROTO_FTP;
+       if (is_transport_allowed("ftps", from_user))
+               allowed_protocols |= CURLPROTO_FTPS;
+
+       return allowed_protocols;
+}
+
+static CURL *get_curl_handle(void)
+{
+       CURL *result = curl_easy_init();
+
+       if (!result)
+               die("curl_easy_init failed");
+
+       if (!curl_ssl_verify) {
+               curl_easy_setopt(result, CURLOPT_SSL_VERIFYPEER, 0);
+               curl_easy_setopt(result, CURLOPT_SSL_VERIFYHOST, 0);
+       } else {
+               /* Verify authenticity of the peer's certificate */
+               curl_easy_setopt(result, CURLOPT_SSL_VERIFYPEER, 1);
+               /* The name in the cert must match whom we tried to connect */
+               curl_easy_setopt(result, CURLOPT_SSL_VERIFYHOST, 2);
+       }
 
-       curl_easy_setopt(result, CURLOPT_SSL_VERIFYPEER, curl_ssl_verify);
 #if LIBCURL_VERSION_NUM >= 0x070907
        curl_easy_setopt(result, CURLOPT_NETRC, CURL_NETRC_OPTIONAL);
 #endif
+#ifdef LIBCURL_CAN_HANDLE_AUTH_ANY
+       curl_easy_setopt(result, CURLOPT_HTTPAUTH, CURLAUTH_ANY);
+#endif
+
+#if LIBCURL_VERSION_NUM >= 0x071600
+       if (curl_deleg) {
+               int i;
+               for (i = 0; i < ARRAY_SIZE(curl_deleg_levels); i++) {
+                       if (!strcmp(curl_deleg, curl_deleg_levels[i].name)) {
+                               curl_easy_setopt(result, CURLOPT_GSSAPI_DELEGATION,
+                                               curl_deleg_levels[i].curl_deleg_param);
+                               break;
+                       }
+               }
+               if (i == ARRAY_SIZE(curl_deleg_levels))
+                       warning("Unknown delegation method '%s': using default",
+                               curl_deleg);
+       }
+#endif
+
+       if (http_proactive_auth)
+               init_curl_http_auth(result);
+
+       if (getenv("GIT_SSL_VERSION"))
+               ssl_version = getenv("GIT_SSL_VERSION");
+       if (ssl_version && *ssl_version) {
+               int i;
+               for (i = 0; i < ARRAY_SIZE(sslversions); i++) {
+                       if (!strcmp(ssl_version, sslversions[i].name)) {
+                               curl_easy_setopt(result, CURLOPT_SSLVERSION,
+                                                sslversions[i].ssl_version);
+                               break;
+                       }
+               }
+               if (i == ARRAY_SIZE(sslversions))
+                       warning("unsupported ssl version %s: using default",
+                               ssl_version);
+       }
+
+       if (getenv("GIT_SSL_CIPHER_LIST"))
+               ssl_cipherlist = getenv("GIT_SSL_CIPHER_LIST");
+       if (ssl_cipherlist != NULL && *ssl_cipherlist)
+               curl_easy_setopt(result, CURLOPT_SSL_CIPHER_LIST,
+                               ssl_cipherlist);
 
        if (ssl_cert != NULL)
                curl_easy_setopt(result, CURLOPT_SSLCERT, ssl_cert);
-#if LIBCURL_VERSION_NUM >= 0x070902
+       if (has_cert_password())
+               curl_easy_setopt(result, CURLOPT_KEYPASSWD, cert_auth.password);
+#if LIBCURL_VERSION_NUM >= 0x070903
        if (ssl_key != NULL)
                curl_easy_setopt(result, CURLOPT_SSLKEY, ssl_key);
 #endif
 #if LIBCURL_VERSION_NUM >= 0x070908
        if (ssl_capath != NULL)
                curl_easy_setopt(result, CURLOPT_CAPATH, ssl_capath);
+#endif
+#if LIBCURL_VERSION_NUM >= 0x072c00
+       if (ssl_pinnedkey != NULL)
+               curl_easy_setopt(result, CURLOPT_PINNEDPUBLICKEY, ssl_pinnedkey);
 #endif
        if (ssl_cainfo != NULL)
                curl_easy_setopt(result, CURLOPT_CAINFO, ssl_cainfo);
-       curl_easy_setopt(result, CURLOPT_FAILONERROR, 1);
 
        if (curl_low_speed_limit > 0 && curl_low_speed_time > 0) {
                curl_easy_setopt(result, CURLOPT_LOW_SPEED_LIMIT,
@@ -191,33 +781,141 @@ static CURL* get_curl_handle(void)
                                 curl_low_speed_time);
        }
 
-       curl_easy_setopt(result, CURLOPT_FOLLOWLOCATION, 1);
-
+       curl_easy_setopt(result, CURLOPT_MAXREDIRS, 20);
+#if LIBCURL_VERSION_NUM >= 0x071301
+       curl_easy_setopt(result, CURLOPT_POSTREDIR, CURL_REDIR_POST_ALL);
+#elif LIBCURL_VERSION_NUM >= 0x071101
+       curl_easy_setopt(result, CURLOPT_POST301, 1);
+#endif
+#if LIBCURL_VERSION_NUM >= 0x071304
+       curl_easy_setopt(result, CURLOPT_REDIR_PROTOCOLS,
+                        get_curl_allowed_protocols(0));
+       curl_easy_setopt(result, CURLOPT_PROTOCOLS,
+                        get_curl_allowed_protocols(-1));
+#else
+       warning("protocol restrictions not applied to curl redirects because\n"
+               "your curl version is too old (>= 7.19.4)");
+#endif
        if (getenv("GIT_CURL_VERBOSE"))
-               curl_easy_setopt(result, CURLOPT_VERBOSE, 1);
+               curl_easy_setopt(result, CURLOPT_VERBOSE, 1L);
+       setup_curl_trace(result);
 
-       curl_easy_setopt(result, CURLOPT_USERAGENT, GIT_USER_AGENT);
+       curl_easy_setopt(result, CURLOPT_USERAGENT,
+               user_agent ? user_agent : git_user_agent());
 
        if (curl_ftp_no_epsv)
                curl_easy_setopt(result, CURLOPT_FTP_USE_EPSV, 0);
 
-       if (curl_http_proxy)
+#ifdef CURLOPT_USE_SSL
+       if (curl_ssl_try)
+               curl_easy_setopt(result, CURLOPT_USE_SSL, CURLUSESSL_TRY);
+#endif
+
+       /*
+        * CURL also examines these variables as a fallback; but we need to query
+        * them here in order to decide whether to prompt for missing password (cf.
+        * init_curl_proxy_auth()).
+        *
+        * Unlike many other common environment variables, these are historically
+        * lowercase only. It appears that CURL did not know this and implemented
+        * only uppercase variants, which was later corrected to take both - with
+        * the exception of http_proxy, which is lowercase only also in CURL. As
+        * the lowercase versions are the historical quasi-standard, they take
+        * precedence here, as in CURL.
+        */
+       if (!curl_http_proxy) {
+               if (http_auth.protocol && !strcmp(http_auth.protocol, "https")) {
+                       var_override(&curl_http_proxy, getenv("HTTPS_PROXY"));
+                       var_override(&curl_http_proxy, getenv("https_proxy"));
+               } else {
+                       var_override(&curl_http_proxy, getenv("http_proxy"));
+               }
+               if (!curl_http_proxy) {
+                       var_override(&curl_http_proxy, getenv("ALL_PROXY"));
+                       var_override(&curl_http_proxy, getenv("all_proxy"));
+               }
+       }
+
+       if (curl_http_proxy) {
                curl_easy_setopt(result, CURLOPT_PROXY, curl_http_proxy);
+#if LIBCURL_VERSION_NUM >= 0x071800
+               if (starts_with(curl_http_proxy, "socks5h"))
+                       curl_easy_setopt(result,
+                               CURLOPT_PROXYTYPE, CURLPROXY_SOCKS5_HOSTNAME);
+               else if (starts_with(curl_http_proxy, "socks5"))
+                       curl_easy_setopt(result,
+                               CURLOPT_PROXYTYPE, CURLPROXY_SOCKS5);
+               else if (starts_with(curl_http_proxy, "socks4a"))
+                       curl_easy_setopt(result,
+                               CURLOPT_PROXYTYPE, CURLPROXY_SOCKS4A);
+               else if (starts_with(curl_http_proxy, "socks"))
+                       curl_easy_setopt(result,
+                               CURLOPT_PROXYTYPE, CURLPROXY_SOCKS4);
+#endif
+               if (strstr(curl_http_proxy, "://"))
+                       credential_from_url(&proxy_auth, curl_http_proxy);
+               else {
+                       struct strbuf url = STRBUF_INIT;
+                       strbuf_addf(&url, "http://%s", curl_http_proxy);
+                       credential_from_url(&proxy_auth, url.buf);
+                       strbuf_release(&url);
+               }
+
+               curl_easy_setopt(result, CURLOPT_PROXY, proxy_auth.host);
+#if LIBCURL_VERSION_NUM >= 0x071304
+               var_override(&curl_no_proxy, getenv("NO_PROXY"));
+               var_override(&curl_no_proxy, getenv("no_proxy"));
+               curl_easy_setopt(result, CURLOPT_NOPROXY, curl_no_proxy);
+#endif
+       }
+       init_curl_proxy_auth(result);
+
+       set_curl_keepalive(result);
 
        return result;
 }
 
-void http_init(struct remote *remote)
+static void set_from_env(const char **var, const char *envname)
+{
+       const char *val = getenv(envname);
+       if (val)
+               *var = val;
+}
+
+void http_init(struct remote *remote, const char *url, int proactive_auth)
 {
        char *low_speed_limit;
        char *low_speed_time;
+       char *normalized_url;
+       struct urlmatch_config config = { STRING_LIST_INIT_DUP };
+
+       config.section = "http";
+       config.key = NULL;
+       config.collect_fn = http_options;
+       config.cascade_fn = git_default_config;
+       config.cb = NULL;
+
+       http_is_verbose = 0;
+       normalized_url = url_normalize(url, &config.url);
+
+       git_config(urlmatch_config_entry, &config);
+       free(normalized_url);
+
+       if (curl_global_init(CURL_GLOBAL_ALL) != CURLE_OK)
+               die("curl_global_init failed");
 
-       curl_global_init(CURL_GLOBAL_ALL);
+       http_proactive_auth = proactive_auth;
 
        if (remote && remote->http_proxy)
                curl_http_proxy = xstrdup(remote->http_proxy);
 
-       pragma_header = curl_slist_append(pragma_header, "Pragma: no-cache");
+       if (remote)
+               var_override(&http_proxy_authmethod, remote->http_proxy_authmethod);
+
+       pragma_header = curl_slist_append(http_copy_default_headers(),
+               "Pragma: no-cache");
+       no_pragma_header = curl_slist_append(http_copy_default_headers(),
+               "Pragma:");
 
 #ifdef USE_CURL_MULTI
        {
@@ -227,23 +925,23 @@ void http_init(struct remote *remote)
        }
 
        curlm = curl_multi_init();
-       if (curlm == NULL) {
-               fprintf(stderr, "Error creating curl multi handle.\n");
-               exit(1);
-       }
+       if (!curlm)
+               die("curl_multi_init failed");
 #endif
 
        if (getenv("GIT_SSL_NO_VERIFY"))
                curl_ssl_verify = 0;
 
-       ssl_cert = getenv("GIT_SSL_CERT");
-#if LIBCURL_VERSION_NUM >= 0x070902
-       ssl_key = getenv("GIT_SSL_KEY");
+       set_from_env(&ssl_cert, "GIT_SSL_CERT");
+#if LIBCURL_VERSION_NUM >= 0x070903
+       set_from_env(&ssl_key, "GIT_SSL_KEY");
 #endif
 #if LIBCURL_VERSION_NUM >= 0x070908
-       ssl_capath = getenv("GIT_SSL_CAPATH");
+       set_from_env(&ssl_capath, "GIT_SSL_CAPATH");
 #endif
-       ssl_cainfo = getenv("GIT_SSL_CAINFO");
+       set_from_env(&ssl_cainfo, "GIT_SSL_CAINFO");
+
+       set_from_env(&user_agent, "GIT_HTTP_USER_AGENT");
 
        low_speed_limit = getenv("GIT_HTTP_LOW_SPEED_LIMIT");
        if (low_speed_limit != NULL)
@@ -252,11 +950,10 @@ void http_init(struct remote *remote)
        if (low_speed_time != NULL)
                curl_low_speed_time = strtol(low_speed_time, NULL, 10);
 
-       git_config(http_options, NULL);
-
        if (curl_ssl_verify == -1)
                curl_ssl_verify = 1;
 
+       curl_session_count = 0;
 #ifdef USE_CURL_MULTI
        if (max_requests < 1)
                max_requests = DEFAULT_MAX_REQUESTS;
@@ -265,6 +962,14 @@ void http_init(struct remote *remote)
        if (getenv("GIT_CURL_FTP_NO_EPSV"))
                curl_ftp_no_epsv = 1;
 
+       if (url) {
+               credential_from_url(&http_auth, url);
+               if (!ssl_cert_password_required &&
+                   getenv("GIT_SSL_CERT_PASSWORD_PROTECTED") &&
+                   starts_with(url, "https://"))
+                       ssl_cert_password_required = 1;
+       }
+
 #ifndef NO_CURL_EASY_DUPHANDLE
        curl_default = get_curl_handle();
 #endif
@@ -277,9 +982,7 @@ void http_cleanup(void)
        while (slot != NULL) {
                struct active_request_slot *next = slot->next;
                if (slot->curl != NULL) {
-#ifdef USE_CURL_MULTI
-                       curl_multi_remove_handle(curlm, slot->curl);
-#endif
+                       xmulti_remove_handle(slot);
                        curl_easy_cleanup(slot->curl);
                }
                free(slot);
@@ -296,19 +999,47 @@ void http_cleanup(void)
 #endif
        curl_global_cleanup();
 
+       curl_slist_free_all(extra_http_headers);
+       extra_http_headers = NULL;
+
        curl_slist_free_all(pragma_header);
        pragma_header = NULL;
 
+       curl_slist_free_all(no_pragma_header);
+       no_pragma_header = NULL;
+
        if (curl_http_proxy) {
-               free(curl_http_proxy);
+               free((void *)curl_http_proxy);
                curl_http_proxy = NULL;
        }
-}
 
-struct active_request_slot *get_active_slot(void)
-{
-       struct active_request_slot *slot = active_queue_head;
-       struct active_request_slot *newslot;
+       if (proxy_auth.password) {
+               memset(proxy_auth.password, 0, strlen(proxy_auth.password));
+               free(proxy_auth.password);
+               proxy_auth.password = NULL;
+       }
+
+       free((void *)curl_proxyuserpwd);
+       curl_proxyuserpwd = NULL;
+
+       free((void *)http_proxy_authmethod);
+       http_proxy_authmethod = NULL;
+
+       if (cert_auth.password != NULL) {
+               memset(cert_auth.password, 0, strlen(cert_auth.password));
+               free(cert_auth.password);
+               cert_auth.password = NULL;
+       }
+       ssl_cert_password_required = 0;
+
+       free(cached_accept_language);
+       cached_accept_language = NULL;
+}
+
+struct active_request_slot *get_active_slot(void)
+{
+       struct active_request_slot *slot = active_queue_head;
+       struct active_request_slot *newslot;
 
 #ifdef USE_CURL_MULTI
        int num_transfers;
@@ -316,15 +1047,14 @@ struct active_request_slot *get_active_slot(void)
        /* Wait for a slot to open up if the queue is full */
        while (active_requests >= max_requests) {
                curl_multi_perform(curlm, &num_transfers);
-               if (num_transfers < active_requests) {
+               if (num_transfers < active_requests)
                        process_curl_messages();
-               }
        }
 #endif
 
-       while (slot != NULL && slot->in_use) {
+       while (slot != NULL && slot->in_use)
                slot = slot->next;
-       }
+
        if (slot == NULL) {
                newslot = xmalloc(sizeof(*newslot));
                newslot->curl = NULL;
@@ -335,9 +1065,8 @@ struct active_request_slot *get_active_slot(void)
                if (slot == NULL) {
                        active_queue_head = newslot;
                } else {
-                       while (slot->next != NULL) {
+                       while (slot->next != NULL)
                                slot = slot->next;
-                       }
                        slot->next = newslot;
                }
                slot = newslot;
@@ -349,22 +1078,47 @@ struct active_request_slot *get_active_slot(void)
 #else
                slot->curl = curl_easy_duphandle(curl_default);
 #endif
+               curl_session_count++;
        }
 
        active_requests++;
        slot->in_use = 1;
-       slot->local = NULL;
        slot->results = NULL;
        slot->finished = NULL;
        slot->callback_data = NULL;
        slot->callback_func = NULL;
+       curl_easy_setopt(slot->curl, CURLOPT_COOKIEFILE, curl_cookie_file);
+       if (curl_save_cookies)
+               curl_easy_setopt(slot->curl, CURLOPT_COOKIEJAR, curl_cookie_file);
        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, pragma_header);
        curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, curl_errorstr);
        curl_easy_setopt(slot->curl, CURLOPT_CUSTOMREQUEST, NULL);
        curl_easy_setopt(slot->curl, CURLOPT_READFUNCTION, NULL);
        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, NULL);
+       curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDS, NULL);
        curl_easy_setopt(slot->curl, CURLOPT_UPLOAD, 0);
        curl_easy_setopt(slot->curl, CURLOPT_HTTPGET, 1);
+       curl_easy_setopt(slot->curl, CURLOPT_FAILONERROR, 1);
+       curl_easy_setopt(slot->curl, CURLOPT_RANGE, NULL);
+
+       /*
+        * Default following to off unless "ALWAYS" is configured; this gives
+        * callers a sane starting point, and they can tweak for individual
+        * HTTP_FOLLOW_* cases themselves.
+        */
+       if (http_follow_config == HTTP_FOLLOW_ALWAYS)
+               curl_easy_setopt(slot->curl, CURLOPT_FOLLOWLOCATION, 1);
+       else
+               curl_easy_setopt(slot->curl, CURLOPT_FOLLOWLOCATION, 0);
+
+#if LIBCURL_VERSION_NUM >= 0x070a08
+       curl_easy_setopt(slot->curl, CURLOPT_IPRESOLVE, git_curl_ipresolve);
+#endif
+#ifdef LIBCURL_CAN_HANDLE_AUTH_ANY
+       curl_easy_setopt(slot->curl, CURLOPT_HTTPAUTH, http_auth_methods);
+#endif
+       if (http_auth.password || curl_empty_auth_enabled())
+               init_curl_http_auth(slot->curl);
 
        return slot;
 }
@@ -377,6 +1131,8 @@ int start_active_slot(struct active_request_slot *slot)
 
        if (curlm_result != CURLM_OK &&
            curlm_result != CURLM_CALL_MULTI_PERFORM) {
+               warning("curl_multi_add_handle failed: %s",
+                       curl_multi_strerror(curlm_result));
                active_requests--;
                slot->in_use = 0;
                return 0;
@@ -398,11 +1154,11 @@ struct fill_chain {
        struct fill_chain *next;
 };
 
-static struct fill_chain *fill_cfg = NULL;
+static struct fill_chain *fill_cfg;
 
 void add_fill_function(void *data, int (*fill)(void *))
 {
-       struct fill_chain *new = malloc(sizeof(*new));
+       struct fill_chain *new = xmalloc(sizeof(*new));
        struct fill_chain **linkp = &fill_cfg;
        new->data = data;
        new->fill = fill;
@@ -427,9 +1183,11 @@ void fill_active_slots(void)
        }
 
        while (slot != NULL) {
-               if (!slot->in_use && slot->curl != NULL) {
+               if (!slot->in_use && slot->curl != NULL
+                       && curl_session_count > min_curl_sessions) {
                        curl_easy_cleanup(slot->curl);
                        slot->curl = NULL;
+                       curl_session_count--;
                }
                slot = slot->next;
        }
@@ -453,8 +1211,6 @@ void step_active_slots(void)
 void run_active_slot(struct active_request_slot *slot)
 {
 #ifdef USE_CURL_MULTI
-       long last_pos = 0;
-       long current_pos;
        fd_set readfds;
        fd_set writefds;
        fd_set excfds;
@@ -464,25 +1220,45 @@ void run_active_slot(struct active_request_slot *slot)
 
        slot->finished = &finished;
        while (!finished) {
-               data_received = 0;
                step_active_slots();
 
-               if (!data_received && slot->local != NULL) {
-                       current_pos = ftell(slot->local);
-                       if (current_pos > last_pos)
-                               data_received++;
-                       last_pos = current_pos;
-               }
+               if (slot->in_use) {
+#if LIBCURL_VERSION_NUM >= 0x070f04
+                       long curl_timeout;
+                       curl_multi_timeout(curlm, &curl_timeout);
+                       if (curl_timeout == 0) {
+                               continue;
+                       } else if (curl_timeout == -1) {
+                               select_timeout.tv_sec  = 0;
+                               select_timeout.tv_usec = 50000;
+                       } else {
+                               select_timeout.tv_sec  =  curl_timeout / 1000;
+                               select_timeout.tv_usec = (curl_timeout % 1000) * 1000;
+                       }
+#else
+                       select_timeout.tv_sec  = 0;
+                       select_timeout.tv_usec = 50000;
+#endif
 
-               if (slot->in_use && !data_received) {
-                       max_fd = 0;
+                       max_fd = -1;
                        FD_ZERO(&readfds);
                        FD_ZERO(&writefds);
                        FD_ZERO(&excfds);
-                       select_timeout.tv_sec = 0;
-                       select_timeout.tv_usec = 50000;
-                       select(max_fd, &readfds, &writefds,
-                              &excfds, &select_timeout);
+                       curl_multi_fdset(curlm, &readfds, &writefds, &excfds, &max_fd);
+
+                       /*
+                        * It can happen that curl_multi_timeout returns a pathologically
+                        * long timeout when curl_multi_fdset returns no file descriptors
+                        * to read.  See commit message for more details.
+                        */
+                       if (max_fd < 0 &&
+                           (select_timeout.tv_sec > 0 ||
+                            select_timeout.tv_usec > 50000)) {
+                               select_timeout.tv_sec  = 0;
+                               select_timeout.tv_usec = 50000;
+                       }
+
+                       select(max_fd+1, &readfds, &writefds, &excfds, &select_timeout);
                }
        }
 #else
@@ -493,47 +1269,22 @@ void run_active_slot(struct active_request_slot *slot)
 #endif
 }
 
-static void closedown_active_slot(struct active_request_slot *slot)
-{
-       active_requests--;
-       slot->in_use = 0;
-}
-
-void release_active_slot(struct active_request_slot *slot)
+static void release_active_slot(struct active_request_slot *slot)
 {
        closedown_active_slot(slot);
        if (slot->curl) {
-#ifdef USE_CURL_MULTI
-               curl_multi_remove_handle(curlm, slot->curl);
-#endif
-               curl_easy_cleanup(slot->curl);
-               slot->curl = NULL;
+               xmulti_remove_handle(slot);
+               if (curl_session_count > min_curl_sessions) {
+                       curl_easy_cleanup(slot->curl);
+                       slot->curl = NULL;
+                       curl_session_count--;
+               }
        }
 #ifdef USE_CURL_MULTI
        fill_active_slots();
 #endif
 }
 
-static void finish_active_slot(struct active_request_slot *slot)
-{
-       closedown_active_slot(slot);
-       curl_easy_getinfo(slot->curl, CURLINFO_HTTP_CODE, &slot->http_code);
-
-       if (slot->finished != NULL)
-               (*slot->finished) = 1;
-
-       /* Store slot results so they can be read after the slot is reused */
-       if (slot->results != NULL) {
-               slot->results->curl_result = slot->curl_result;
-               slot->results->http_code = slot->http_code;
-       }
-
-       /* Run callback if appropriate */
-       if (slot->callback_func != NULL) {
-               slot->callback_func(slot->callback_data);
-       }
-}
-
 void finish_all_active_slots(void)
 {
        struct active_request_slot *slot = active_queue_head;
@@ -547,6 +1298,7 @@ void finish_all_active_slots(void)
                }
 }
 
+/* Helpers for modifying and creating URLs */
 static inline int needs_quote(int ch)
 {
        if (((ch >= 'A') && (ch <= 'Z'))
@@ -559,76 +1311,1019 @@ static inline int needs_quote(int ch)
        return 1;
 }
 
-static inline int hex(int v)
-{
-       if (v < 10) return '0' + v;
-       else return 'A' + v - 10;
-}
-
 static char *quote_ref_url(const char *base, const char *ref)
 {
+       struct strbuf buf = STRBUF_INIT;
        const char *cp;
-       char *dp, *qref;
-       int len, baselen, ch;
+       int ch;
 
-       baselen = strlen(base);
-       len = baselen + 2; /* '/' after base and terminating NUL */
-       for (cp = ref; (ch = *cp) != 0; cp++, len++)
+       end_url_with_slash(&buf, base);
+
+       for (cp = ref; (ch = *cp) != 0; cp++)
                if (needs_quote(ch))
-                       len += 2; /* extra two hex plus replacement % */
-       qref = xmalloc(len);
-       memcpy(qref, base, baselen);
-       dp = qref + baselen;
-       *(dp++) = '/';
-       for (cp = ref; (ch = *cp) != 0; cp++) {
-               if (needs_quote(ch)) {
-                       *dp++ = '%';
-                       *dp++ = hex((ch >> 4) & 0xF);
-                       *dp++ = hex(ch & 0xF);
-               }
+                       strbuf_addf(&buf, "%%%02x", ch);
                else
-                       *dp++ = ch;
+                       strbuf_addch(&buf, *cp);
+
+       return strbuf_detach(&buf, NULL);
+}
+
+void append_remote_object_url(struct strbuf *buf, const char *url,
+                             const char *hex,
+                             int only_two_digit_prefix)
+{
+       end_url_with_slash(buf, url);
+
+       strbuf_addf(buf, "objects/%.*s/", 2, hex);
+       if (!only_two_digit_prefix)
+               strbuf_addstr(buf, hex + 2);
+}
+
+char *get_remote_object_url(const char *url, const char *hex,
+                           int only_two_digit_prefix)
+{
+       struct strbuf buf = STRBUF_INIT;
+       append_remote_object_url(&buf, url, hex, only_two_digit_prefix);
+       return strbuf_detach(&buf, NULL);
+}
+
+static int handle_curl_result(struct slot_results *results)
+{
+       /*
+        * If we see a failing http code with CURLE_OK, we have turned off
+        * FAILONERROR (to keep the server's custom error response), and should
+        * translate the code into failure here.
+        *
+        * Likewise, if we see a redirect (30x code), that means we turned off
+        * redirect-following, and we should treat the result as an error.
+        */
+       if (results->curl_result == CURLE_OK &&
+           results->http_code >= 300) {
+               results->curl_result = CURLE_HTTP_RETURNED_ERROR;
+               /*
+                * Normally curl will already have put the "reason phrase"
+                * from the server into curl_errorstr; unfortunately without
+                * FAILONERROR it is lost, so we can give only the numeric
+                * status code.
+                */
+               snprintf(curl_errorstr, sizeof(curl_errorstr),
+                        "The requested URL returned error: %ld",
+                        results->http_code);
        }
-       *dp = 0;
 
-       return qref;
+       if (results->curl_result == CURLE_OK) {
+               credential_approve(&http_auth);
+               if (proxy_auth.password)
+                       credential_approve(&proxy_auth);
+               return HTTP_OK;
+       } else if (missing_target(results))
+               return HTTP_MISSING_TARGET;
+       else if (results->http_code == 401) {
+               if (http_auth.username && http_auth.password) {
+                       credential_reject(&http_auth);
+                       return HTTP_NOAUTH;
+               } else {
+#ifdef LIBCURL_CAN_HANDLE_AUTH_ANY
+                       http_auth_methods &= ~CURLAUTH_GSSNEGOTIATE;
+                       if (results->auth_avail) {
+                               http_auth_methods &= results->auth_avail;
+                               http_auth_methods_restricted = 1;
+                       }
+#endif
+                       return HTTP_REAUTH;
+               }
+       } else {
+               if (results->http_connectcode == 407)
+                       credential_reject(&proxy_auth);
+#if LIBCURL_VERSION_NUM >= 0x070c00
+               if (!curl_errorstr[0])
+                       strlcpy(curl_errorstr,
+                               curl_easy_strerror(results->curl_result),
+                               sizeof(curl_errorstr));
+#endif
+               return HTTP_ERROR;
+       }
 }
 
-int http_fetch_ref(const char *base, struct ref *ref)
+int run_one_slot(struct active_request_slot *slot,
+                struct slot_results *results)
+{
+       slot->results = results;
+       if (!start_active_slot(slot)) {
+               snprintf(curl_errorstr, sizeof(curl_errorstr),
+                        "failed to start HTTP request");
+               return HTTP_START_FAILED;
+       }
+
+       run_active_slot(slot);
+       return handle_curl_result(results);
+}
+
+struct curl_slist *http_copy_default_headers(void)
+{
+       struct curl_slist *headers = NULL, *h;
+
+       for (h = extra_http_headers; h; h = h->next)
+               headers = curl_slist_append(headers, h->data);
+
+       return headers;
+}
+
+static CURLcode curlinfo_strbuf(CURL *curl, CURLINFO info, struct strbuf *buf)
+{
+       char *ptr;
+       CURLcode ret;
+
+       strbuf_reset(buf);
+       ret = curl_easy_getinfo(curl, info, &ptr);
+       if (!ret && ptr)
+               strbuf_addstr(buf, ptr);
+       return ret;
+}
+
+/*
+ * Check for and extract a content-type parameter. "raw"
+ * should be positioned at the start of the potential
+ * parameter, with any whitespace already removed.
+ *
+ * "name" is the name of the parameter. The value is appended
+ * to "out".
+ */
+static int extract_param(const char *raw, const char *name,
+                        struct strbuf *out)
+{
+       size_t len = strlen(name);
+
+       if (strncasecmp(raw, name, len))
+               return -1;
+       raw += len;
+
+       if (*raw != '=')
+               return -1;
+       raw++;
+
+       while (*raw && !isspace(*raw) && *raw != ';')
+               strbuf_addch(out, *raw++);
+       return 0;
+}
+
+/*
+ * Extract a normalized version of the content type, with any
+ * spaces suppressed, all letters lowercased, and no trailing ";"
+ * or parameters.
+ *
+ * Note that we will silently remove even invalid whitespace. For
+ * example, "text / plain" is specifically forbidden by RFC 2616,
+ * but "text/plain" is the only reasonable output, and this keeps
+ * our code simple.
+ *
+ * If the "charset" argument is not NULL, store the value of any
+ * charset parameter there.
+ *
+ * Example:
+ *   "TEXT/PLAIN; charset=utf-8" -> "text/plain", "utf-8"
+ *   "text / plain" -> "text/plain"
+ */
+static void extract_content_type(struct strbuf *raw, struct strbuf *type,
+                                struct strbuf *charset)
+{
+       const char *p;
+
+       strbuf_reset(type);
+       strbuf_grow(type, raw->len);
+       for (p = raw->buf; *p; p++) {
+               if (isspace(*p))
+                       continue;
+               if (*p == ';') {
+                       p++;
+                       break;
+               }
+               strbuf_addch(type, tolower(*p));
+       }
+
+       if (!charset)
+               return;
+
+       strbuf_reset(charset);
+       while (*p) {
+               while (isspace(*p) || *p == ';')
+                       p++;
+               if (!extract_param(p, "charset", charset))
+                       return;
+               while (*p && !isspace(*p))
+                       p++;
+       }
+
+       if (!charset->len && starts_with(type->buf, "text/"))
+               strbuf_addstr(charset, "ISO-8859-1");
+}
+
+static void write_accept_language(struct strbuf *buf)
+{
+       /*
+        * MAX_DECIMAL_PLACES must not be larger than 3. If it is larger than
+        * that, q-value will be smaller than 0.001, the minimum q-value the
+        * HTTP specification allows. See
+        * http://tools.ietf.org/html/rfc7231#section-5.3.1 for q-value.
+        */
+       const int MAX_DECIMAL_PLACES = 3;
+       const int MAX_LANGUAGE_TAGS = 1000;
+       const int MAX_ACCEPT_LANGUAGE_HEADER_SIZE = 4000;
+       char **language_tags = NULL;
+       int num_langs = 0;
+       const char *s = get_preferred_languages();
+       int i;
+       struct strbuf tag = STRBUF_INIT;
+
+       /* Don't add Accept-Language header if no language is preferred. */
+       if (!s)
+               return;
+
+       /*
+        * Split the colon-separated string of preferred languages into
+        * language_tags array.
+        */
+       do {
+               /* collect language tag */
+               for (; *s && (isalnum(*s) || *s == '_'); s++)
+                       strbuf_addch(&tag, *s == '_' ? '-' : *s);
+
+               /* skip .codeset, @modifier and any other unnecessary parts */
+               while (*s && *s != ':')
+                       s++;
+
+               if (tag.len) {
+                       num_langs++;
+                       REALLOC_ARRAY(language_tags, num_langs);
+                       language_tags[num_langs - 1] = strbuf_detach(&tag, NULL);
+                       if (num_langs >= MAX_LANGUAGE_TAGS - 1) /* -1 for '*' */
+                               break;
+               }
+       } while (*s++);
+
+       /* write Accept-Language header into buf */
+       if (num_langs) {
+               int last_buf_len = 0;
+               int max_q;
+               int decimal_places;
+               char q_format[32];
+
+               /* add '*' */
+               REALLOC_ARRAY(language_tags, num_langs + 1);
+               language_tags[num_langs++] = "*"; /* it's OK; this won't be freed */
+
+               /* compute decimal_places */
+               for (max_q = 1, decimal_places = 0;
+                    max_q < num_langs && decimal_places <= MAX_DECIMAL_PLACES;
+                    decimal_places++, max_q *= 10)
+                       ;
+
+               xsnprintf(q_format, sizeof(q_format), ";q=0.%%0%dd", decimal_places);
+
+               strbuf_addstr(buf, "Accept-Language: ");
+
+               for (i = 0; i < num_langs; i++) {
+                       if (i > 0)
+                               strbuf_addstr(buf, ", ");
+
+                       strbuf_addstr(buf, language_tags[i]);
+
+                       if (i > 0)
+                               strbuf_addf(buf, q_format, max_q - i);
+
+                       if (buf->len > MAX_ACCEPT_LANGUAGE_HEADER_SIZE) {
+                               strbuf_remove(buf, last_buf_len, buf->len - last_buf_len);
+                               break;
+                       }
+
+                       last_buf_len = buf->len;
+               }
+       }
+
+       /* free language tags -- last one is a static '*' */
+       for (i = 0; i < num_langs - 1; i++)
+               free(language_tags[i]);
+       free(language_tags);
+}
+
+/*
+ * Get an Accept-Language header which indicates user's preferred languages.
+ *
+ * Examples:
+ *   LANGUAGE= -> ""
+ *   LANGUAGE=ko:en -> "Accept-Language: ko, en; q=0.9, *; q=0.1"
+ *   LANGUAGE=ko_KR.UTF-8:sr@latin -> "Accept-Language: ko-KR, sr; q=0.9, *; q=0.1"
+ *   LANGUAGE=ko LANG=en_US.UTF-8 -> "Accept-Language: ko, *; q=0.1"
+ *   LANGUAGE= LANG=en_US.UTF-8 -> "Accept-Language: en-US, *; q=0.1"
+ *   LANGUAGE= LANG=C -> ""
+ */
+static const char *get_accept_language(void)
+{
+       if (!cached_accept_language) {
+               struct strbuf buf = STRBUF_INIT;
+               write_accept_language(&buf);
+               if (buf.len > 0)
+                       cached_accept_language = strbuf_detach(&buf, NULL);
+       }
+
+       return cached_accept_language;
+}
+
+static void http_opt_request_remainder(CURL *curl, off_t pos)
+{
+       char buf[128];
+       xsnprintf(buf, sizeof(buf), "%"PRIuMAX"-", (uintmax_t)pos);
+       curl_easy_setopt(curl, CURLOPT_RANGE, buf);
+}
+
+/* http_request() targets */
+#define HTTP_REQUEST_STRBUF    0
+#define HTTP_REQUEST_FILE      1
+
+static int http_request(const char *url,
+                       void *result, int target,
+                       const struct http_get_options *options)
 {
-       char *url;
-       struct strbuf buffer = STRBUF_INIT;
        struct active_request_slot *slot;
        struct slot_results results;
+       struct curl_slist *headers = http_copy_default_headers();
+       struct strbuf buf = STRBUF_INIT;
+       const char *accept_language;
        int ret;
 
-       url = quote_ref_url(base, ref->name);
        slot = get_active_slot();
-       slot->results = &results;
-       curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
-       curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
-       curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
+       curl_easy_setopt(slot->curl, CURLOPT_HTTPGET, 1);
+
+       if (result == NULL) {
+               curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 1);
+       } else {
+               curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 0);
+               curl_easy_setopt(slot->curl, CURLOPT_FILE, result);
+
+               if (target == HTTP_REQUEST_FILE) {
+                       off_t posn = ftello(result);
+                       curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
+                                        fwrite);
+                       if (posn > 0)
+                               http_opt_request_remainder(slot->curl, posn);
+               } else
+                       curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
+                                        fwrite_buffer);
+       }
+
+       accept_language = get_accept_language();
+
+       if (accept_language)
+               headers = curl_slist_append(headers, accept_language);
+
+       strbuf_addstr(&buf, "Pragma:");
+       if (options && options->no_cache)
+               strbuf_addstr(&buf, " no-cache");
+       if (options && options->keep_error)
+               curl_easy_setopt(slot->curl, CURLOPT_FAILONERROR, 0);
+       if (options && options->initial_request &&
+           http_follow_config == HTTP_FOLLOW_INITIAL)
+               curl_easy_setopt(slot->curl, CURLOPT_FOLLOWLOCATION, 1);
+
+       headers = curl_slist_append(headers, buf.buf);
+
        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
-       if (start_active_slot(slot)) {
-               run_active_slot(slot);
-               if (results.curl_result == CURLE_OK) {
-                       strbuf_rtrim(&buffer);
-                       if (buffer.len == 40)
-                               ret = get_sha1_hex(buffer.buf, ref->old_sha1);
-                       else if (!prefixcmp(buffer.buf, "ref: ")) {
-                               ref->symref = xstrdup(buffer.buf + 5);
-                               ret = 0;
-                       } else
-                               ret = 1;
-               } else {
-                       ret = error("Couldn't get %s for %s\n%s",
-                                   url, ref->name, curl_errorstr);
+       curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, headers);
+       curl_easy_setopt(slot->curl, CURLOPT_ENCODING, "gzip");
+
+       ret = run_one_slot(slot, &results);
+
+       if (options && options->content_type) {
+               struct strbuf raw = STRBUF_INIT;
+               curlinfo_strbuf(slot->curl, CURLINFO_CONTENT_TYPE, &raw);
+               extract_content_type(&raw, options->content_type,
+                                    options->charset);
+               strbuf_release(&raw);
+       }
+
+       if (options && options->effective_url)
+               curlinfo_strbuf(slot->curl, CURLINFO_EFFECTIVE_URL,
+                               options->effective_url);
+
+       curl_slist_free_all(headers);
+       strbuf_release(&buf);
+
+       return ret;
+}
+
+/*
+ * Update the "base" url to a more appropriate value, as deduced by
+ * redirects seen when requesting a URL starting with "url".
+ *
+ * The "asked" parameter is a URL that we asked curl to access, and must begin
+ * with "base".
+ *
+ * The "got" parameter is the URL that curl reported to us as where we ended
+ * up.
+ *
+ * Returns 1 if we updated the base url, 0 otherwise.
+ *
+ * Our basic strategy is to compare "base" and "asked" to find the bits
+ * specific to our request. We then strip those bits off of "got" to yield the
+ * new base. So for example, if our base is "http://example.com/foo.git",
+ * and we ask for "http://example.com/foo.git/info/refs", we might end up
+ * with "https://other.example.com/foo.git/info/refs". We would want the
+ * new URL to become "https://other.example.com/foo.git".
+ *
+ * Note that this assumes a sane redirect scheme. It's entirely possible
+ * in the example above to end up at a URL that does not even end in
+ * "info/refs".  In such a case we die. There's not much we can do, such a
+ * scheme is unlikely to represent a real git repository, and failing to
+ * rewrite the base opens options for malicious redirects to do funny things.
+ */
+static int update_url_from_redirect(struct strbuf *base,
+                                   const char *asked,
+                                   const struct strbuf *got)
+{
+       const char *tail;
+       size_t new_len;
+
+       if (!strcmp(asked, got->buf))
+               return 0;
+
+       if (!skip_prefix(asked, base->buf, &tail))
+               die("BUG: update_url_from_redirect: %s is not a superset of %s",
+                   asked, base->buf);
+
+       new_len = got->len;
+       if (!strip_suffix_mem(got->buf, &new_len, tail))
+               die(_("unable to update url base from redirection:\n"
+                     "  asked for: %s\n"
+                     "   redirect: %s"),
+                   asked, got->buf);
+
+       strbuf_reset(base);
+       strbuf_add(base, got->buf, new_len);
+
+       return 1;
+}
+
+static int http_request_reauth(const char *url,
+                              void *result, int target,
+                              struct http_get_options *options)
+{
+       int ret = http_request(url, result, target, options);
+
+       if (ret != HTTP_OK && ret != HTTP_REAUTH)
+               return ret;
+
+       if (options && options->effective_url && options->base_url) {
+               if (update_url_from_redirect(options->base_url,
+                                            url, options->effective_url)) {
+                       credential_from_url(&http_auth, options->base_url->buf);
+                       url = options->effective_url->buf;
+               }
+       }
+
+       if (ret != HTTP_REAUTH)
+               return ret;
+
+       /*
+        * If we are using KEEP_ERROR, the previous request may have
+        * put cruft into our output stream; we should clear it out before
+        * making our next request. We only know how to do this for
+        * the strbuf case, but that is enough to satisfy current callers.
+        */
+       if (options && options->keep_error) {
+               switch (target) {
+               case HTTP_REQUEST_STRBUF:
+                       strbuf_reset(result);
+                       break;
+               default:
+                       die("BUG: HTTP_KEEP_ERROR is only supported with strbufs");
+               }
+       }
+
+       credential_fill(&http_auth);
+
+       return http_request(url, result, target, options);
+}
+
+int http_get_strbuf(const char *url,
+                   struct strbuf *result,
+                   struct http_get_options *options)
+{
+       return http_request_reauth(url, result, HTTP_REQUEST_STRBUF, options);
+}
+
+/*
+ * Downloads a URL and stores the result in the given file.
+ *
+ * If a previous interrupted download is detected (i.e. a previous temporary
+ * file is still around) the download is resumed.
+ */
+static int http_get_file(const char *url, const char *filename,
+                        struct http_get_options *options)
+{
+       int ret;
+       struct strbuf tmpfile = STRBUF_INIT;
+       FILE *result;
+
+       strbuf_addf(&tmpfile, "%s.temp", filename);
+       result = fopen(tmpfile.buf, "a");
+       if (!result) {
+               error("Unable to open local file %s", tmpfile.buf);
+               ret = HTTP_ERROR;
+               goto cleanup;
+       }
+
+       ret = http_request_reauth(url, result, HTTP_REQUEST_FILE, options);
+       fclose(result);
+
+       if (ret == HTTP_OK && finalize_object_file(tmpfile.buf, filename))
+               ret = HTTP_ERROR;
+cleanup:
+       strbuf_release(&tmpfile);
+       return ret;
+}
+
+int http_fetch_ref(const char *base, struct ref *ref)
+{
+       struct http_get_options options = {0};
+       char *url;
+       struct strbuf buffer = STRBUF_INIT;
+       int ret = -1;
+
+       options.no_cache = 1;
+
+       url = quote_ref_url(base, ref->name);
+       if (http_get_strbuf(url, &buffer, &options) == HTTP_OK) {
+               strbuf_rtrim(&buffer);
+               if (buffer.len == 40)
+                       ret = get_oid_hex(buffer.buf, &ref->old_oid);
+               else if (starts_with(buffer.buf, "ref: ")) {
+                       ref->symref = xstrdup(buffer.buf + 5);
+                       ret = 0;
                }
-       } else {
-               ret = error("Unable to start request");
        }
 
        strbuf_release(&buffer);
        free(url);
        return ret;
 }
+
+/* Helpers for fetching packs */
+static char *fetch_pack_index(unsigned char *sha1, const char *base_url)
+{
+       char *url, *tmp;
+       struct strbuf buf = STRBUF_INIT;
+
+       if (http_is_verbose)
+               fprintf(stderr, "Getting index for pack %s\n", sha1_to_hex(sha1));
+
+       end_url_with_slash(&buf, base_url);
+       strbuf_addf(&buf, "objects/pack/pack-%s.idx", sha1_to_hex(sha1));
+       url = strbuf_detach(&buf, NULL);
+
+       strbuf_addf(&buf, "%s.temp", sha1_pack_index_name(sha1));
+       tmp = strbuf_detach(&buf, NULL);
+
+       if (http_get_file(url, tmp, NULL) != HTTP_OK) {
+               error("Unable to get pack index %s", url);
+               free(tmp);
+               tmp = NULL;
+       }
+
+       free(url);
+       return tmp;
+}
+
+static int fetch_and_setup_pack_index(struct packed_git **packs_head,
+       unsigned char *sha1, const char *base_url)
+{
+       struct packed_git *new_pack;
+       char *tmp_idx = NULL;
+       int ret;
+
+       if (has_pack_index(sha1)) {
+               new_pack = parse_pack_index(sha1, sha1_pack_index_name(sha1));
+               if (!new_pack)
+                       return -1; /* parse_pack_index() already issued error message */
+               goto add_pack;
+       }
+
+       tmp_idx = fetch_pack_index(sha1, base_url);
+       if (!tmp_idx)
+               return -1;
+
+       new_pack = parse_pack_index(sha1, tmp_idx);
+       if (!new_pack) {
+               unlink(tmp_idx);
+               free(tmp_idx);
+
+               return -1; /* parse_pack_index() already issued error message */
+       }
+
+       ret = verify_pack_index(new_pack);
+       if (!ret) {
+               close_pack_index(new_pack);
+               ret = finalize_object_file(tmp_idx, sha1_pack_index_name(sha1));
+       }
+       free(tmp_idx);
+       if (ret)
+               return -1;
+
+add_pack:
+       new_pack->next = *packs_head;
+       *packs_head = new_pack;
+       return 0;
+}
+
+int http_get_info_packs(const char *base_url, struct packed_git **packs_head)
+{
+       struct http_get_options options = {0};
+       int ret = 0, i = 0;
+       char *url, *data;
+       struct strbuf buf = STRBUF_INIT;
+       unsigned char sha1[20];
+
+       end_url_with_slash(&buf, base_url);
+       strbuf_addstr(&buf, "objects/info/packs");
+       url = strbuf_detach(&buf, NULL);
+
+       options.no_cache = 1;
+       ret = http_get_strbuf(url, &buf, &options);
+       if (ret != HTTP_OK)
+               goto cleanup;
+
+       data = buf.buf;
+       while (i < buf.len) {
+               switch (data[i]) {
+               case 'P':
+                       i++;
+                       if (i + 52 <= buf.len &&
+                           starts_with(data + i, " pack-") &&
+                           starts_with(data + i + 46, ".pack\n")) {
+                               get_sha1_hex(data + i + 6, sha1);
+                               fetch_and_setup_pack_index(packs_head, sha1,
+                                                     base_url);
+                               i += 51;
+                               break;
+                       }
+               default:
+                       while (i < buf.len && data[i] != '\n')
+                               i++;
+               }
+               i++;
+       }
+
+cleanup:
+       free(url);
+       return ret;
+}
+
+void release_http_pack_request(struct http_pack_request *preq)
+{
+       if (preq->packfile != NULL) {
+               fclose(preq->packfile);
+               preq->packfile = NULL;
+       }
+       preq->slot = NULL;
+       free(preq->url);
+       free(preq);
+}
+
+int finish_http_pack_request(struct http_pack_request *preq)
+{
+       struct packed_git **lst;
+       struct packed_git *p = preq->target;
+       char *tmp_idx;
+       size_t len;
+       struct child_process ip = CHILD_PROCESS_INIT;
+       const char *ip_argv[8];
+
+       close_pack_index(p);
+
+       fclose(preq->packfile);
+       preq->packfile = NULL;
+
+       lst = preq->lst;
+       while (*lst != p)
+               lst = &((*lst)->next);
+       *lst = (*lst)->next;
+
+       if (!strip_suffix(preq->tmpfile, ".pack.temp", &len))
+               die("BUG: pack tmpfile does not end in .pack.temp?");
+       tmp_idx = xstrfmt("%.*s.idx.temp", (int)len, preq->tmpfile);
+
+       ip_argv[0] = "index-pack";
+       ip_argv[1] = "-o";
+       ip_argv[2] = tmp_idx;
+       ip_argv[3] = preq->tmpfile;
+       ip_argv[4] = NULL;
+
+       ip.argv = ip_argv;
+       ip.git_cmd = 1;
+       ip.no_stdin = 1;
+       ip.no_stdout = 1;
+
+       if (run_command(&ip)) {
+               unlink(preq->tmpfile);
+               unlink(tmp_idx);
+               free(tmp_idx);
+               return -1;
+       }
+
+       unlink(sha1_pack_index_name(p->sha1));
+
+       if (finalize_object_file(preq->tmpfile, sha1_pack_name(p->sha1))
+        || finalize_object_file(tmp_idx, sha1_pack_index_name(p->sha1))) {
+               free(tmp_idx);
+               return -1;
+       }
+
+       install_packed_git(p);
+       free(tmp_idx);
+       return 0;
+}
+
+struct http_pack_request *new_http_pack_request(
+       struct packed_git *target, const char *base_url)
+{
+       off_t prev_posn = 0;
+       struct strbuf buf = STRBUF_INIT;
+       struct http_pack_request *preq;
+
+       preq = xcalloc(1, sizeof(*preq));
+       preq->target = target;
+
+       end_url_with_slash(&buf, base_url);
+       strbuf_addf(&buf, "objects/pack/pack-%s.pack",
+               sha1_to_hex(target->sha1));
+       preq->url = strbuf_detach(&buf, NULL);
+
+       snprintf(preq->tmpfile, sizeof(preq->tmpfile), "%s.temp",
+               sha1_pack_name(target->sha1));
+       preq->packfile = fopen(preq->tmpfile, "a");
+       if (!preq->packfile) {
+               error("Unable to open local file %s for pack",
+                     preq->tmpfile);
+               goto abort;
+       }
+
+       preq->slot = get_active_slot();
+       curl_easy_setopt(preq->slot->curl, CURLOPT_FILE, preq->packfile);
+       curl_easy_setopt(preq->slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
+       curl_easy_setopt(preq->slot->curl, CURLOPT_URL, preq->url);
+       curl_easy_setopt(preq->slot->curl, CURLOPT_HTTPHEADER,
+               no_pragma_header);
+
+       /*
+        * If there is data present from a previous transfer attempt,
+        * resume where it left off
+        */
+       prev_posn = ftello(preq->packfile);
+       if (prev_posn>0) {
+               if (http_is_verbose)
+                       fprintf(stderr,
+                               "Resuming fetch of pack %s at byte %"PRIuMAX"\n",
+                               sha1_to_hex(target->sha1), (uintmax_t)prev_posn);
+               http_opt_request_remainder(preq->slot->curl, prev_posn);
+       }
+
+       return preq;
+
+abort:
+       free(preq->url);
+       free(preq);
+       return NULL;
+}
+
+/* Helpers for fetching objects (loose) */
+static size_t fwrite_sha1_file(char *ptr, size_t eltsize, size_t nmemb,
+                              void *data)
+{
+       unsigned char expn[4096];
+       size_t size = eltsize * nmemb;
+       int posn = 0;
+       struct http_object_request *freq = data;
+       struct active_request_slot *slot = freq->slot;
+
+       if (slot) {
+               CURLcode c = curl_easy_getinfo(slot->curl, CURLINFO_HTTP_CODE,
+                                               &slot->http_code);
+               if (c != CURLE_OK)
+                       die("BUG: curl_easy_getinfo for HTTP code failed: %s",
+                               curl_easy_strerror(c));
+               if (slot->http_code >= 300)
+                       return size;
+       }
+
+       do {
+               ssize_t retval = xwrite(freq->localfile,
+                                       (char *) ptr + posn, size - posn);
+               if (retval < 0)
+                       return posn;
+               posn += retval;
+       } while (posn < size);
+
+       freq->stream.avail_in = size;
+       freq->stream.next_in = (void *)ptr;
+       do {
+               freq->stream.next_out = expn;
+               freq->stream.avail_out = sizeof(expn);
+               freq->zret = git_inflate(&freq->stream, Z_SYNC_FLUSH);
+               git_SHA1_Update(&freq->c, expn,
+                               sizeof(expn) - freq->stream.avail_out);
+       } while (freq->stream.avail_in && freq->zret == Z_OK);
+       return size;
+}
+
+struct http_object_request *new_http_object_request(const char *base_url,
+       unsigned char *sha1)
+{
+       char *hex = sha1_to_hex(sha1);
+       const char *filename;
+       char prevfile[PATH_MAX];
+       int prevlocal;
+       char prev_buf[PREV_BUF_SIZE];
+       ssize_t prev_read = 0;
+       off_t prev_posn = 0;
+       struct http_object_request *freq;
+
+       freq = xcalloc(1, sizeof(*freq));
+       hashcpy(freq->sha1, sha1);
+       freq->localfile = -1;
+
+       filename = sha1_file_name(sha1);
+       snprintf(freq->tmpfile, sizeof(freq->tmpfile),
+                "%s.temp", filename);
+
+       snprintf(prevfile, sizeof(prevfile), "%s.prev", filename);
+       unlink_or_warn(prevfile);
+       rename(freq->tmpfile, prevfile);
+       unlink_or_warn(freq->tmpfile);
+
+       if (freq->localfile != -1)
+               error("fd leakage in start: %d", freq->localfile);
+       freq->localfile = open(freq->tmpfile,
+                              O_WRONLY | O_CREAT | O_EXCL, 0666);
+       /*
+        * This could have failed due to the "lazy directory creation";
+        * try to mkdir the last path component.
+        */
+       if (freq->localfile < 0 && errno == ENOENT) {
+               char *dir = strrchr(freq->tmpfile, '/');
+               if (dir) {
+                       *dir = 0;
+                       mkdir(freq->tmpfile, 0777);
+                       *dir = '/';
+               }
+               freq->localfile = open(freq->tmpfile,
+                                      O_WRONLY | O_CREAT | O_EXCL, 0666);
+       }
+
+       if (freq->localfile < 0) {
+               error_errno("Couldn't create temporary file %s", freq->tmpfile);
+               goto abort;
+       }
+
+       git_inflate_init(&freq->stream);
+
+       git_SHA1_Init(&freq->c);
+
+       freq->url = get_remote_object_url(base_url, hex, 0);
+
+       /*
+        * If a previous temp file is present, process what was already
+        * fetched.
+        */
+       prevlocal = open(prevfile, O_RDONLY);
+       if (prevlocal != -1) {
+               do {
+                       prev_read = xread(prevlocal, prev_buf, PREV_BUF_SIZE);
+                       if (prev_read>0) {
+                               if (fwrite_sha1_file(prev_buf,
+                                                    1,
+                                                    prev_read,
+                                                    freq) == prev_read) {
+                                       prev_posn += prev_read;
+                               } else {
+                                       prev_read = -1;
+                               }
+                       }
+               } while (prev_read > 0);
+               close(prevlocal);
+       }
+       unlink_or_warn(prevfile);
+
+       /*
+        * Reset inflate/SHA1 if there was an error reading the previous temp
+        * file; also rewind to the beginning of the local file.
+        */
+       if (prev_read == -1) {
+               memset(&freq->stream, 0, sizeof(freq->stream));
+               git_inflate_init(&freq->stream);
+               git_SHA1_Init(&freq->c);
+               if (prev_posn>0) {
+                       prev_posn = 0;
+                       lseek(freq->localfile, 0, SEEK_SET);
+                       if (ftruncate(freq->localfile, 0) < 0) {
+                               error_errno("Couldn't truncate temporary file %s",
+                                           freq->tmpfile);
+                               goto abort;
+                       }
+               }
+       }
+
+       freq->slot = get_active_slot();
+
+       curl_easy_setopt(freq->slot->curl, CURLOPT_FILE, freq);
+       curl_easy_setopt(freq->slot->curl, CURLOPT_FAILONERROR, 0);
+       curl_easy_setopt(freq->slot->curl, CURLOPT_WRITEFUNCTION, fwrite_sha1_file);
+       curl_easy_setopt(freq->slot->curl, CURLOPT_ERRORBUFFER, freq->errorstr);
+       curl_easy_setopt(freq->slot->curl, CURLOPT_URL, freq->url);
+       curl_easy_setopt(freq->slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
+
+       /*
+        * If we have successfully processed data from a previous fetch
+        * attempt, only fetch the data we don't already have.
+        */
+       if (prev_posn>0) {
+               if (http_is_verbose)
+                       fprintf(stderr,
+                               "Resuming fetch of object %s at byte %"PRIuMAX"\n",
+                               hex, (uintmax_t)prev_posn);
+               http_opt_request_remainder(freq->slot->curl, prev_posn);
+       }
+
+       return freq;
+
+abort:
+       free(freq->url);
+       free(freq);
+       return NULL;
+}
+
+void process_http_object_request(struct http_object_request *freq)
+{
+       if (freq->slot == NULL)
+               return;
+       freq->curl_result = freq->slot->curl_result;
+       freq->http_code = freq->slot->http_code;
+       freq->slot = NULL;
+}
+
+int finish_http_object_request(struct http_object_request *freq)
+{
+       struct stat st;
+
+       close(freq->localfile);
+       freq->localfile = -1;
+
+       process_http_object_request(freq);
+
+       if (freq->http_code == 416) {
+               warning("requested range invalid; we may already have all the data.");
+       } else if (freq->curl_result != CURLE_OK) {
+               if (stat(freq->tmpfile, &st) == 0)
+                       if (st.st_size == 0)
+                               unlink_or_warn(freq->tmpfile);
+               return -1;
+       }
+
+       git_inflate_end(&freq->stream);
+       git_SHA1_Final(freq->real_sha1, &freq->c);
+       if (freq->zret != Z_STREAM_END) {
+               unlink_or_warn(freq->tmpfile);
+               return -1;
+       }
+       if (hashcmp(freq->sha1, freq->real_sha1)) {
+               unlink_or_warn(freq->tmpfile);
+               return -1;
+       }
+       freq->rename =
+               finalize_object_file(freq->tmpfile, sha1_file_name(freq->sha1));
+
+       return freq->rename;
+}
+
+void abort_http_object_request(struct http_object_request *freq)
+{
+       unlink_or_warn(freq->tmpfile);
+
+       release_http_object_request(freq);
+}
+
+void release_http_object_request(struct http_object_request *freq)
+{
+       if (freq->localfile != -1) {
+               close(freq->localfile);
+               freq->localfile = -1;
+       }
+       if (freq->url != NULL) {
+               free(freq->url);
+               freq->url = NULL;
+       }
+       if (freq->slot != NULL) {
+               freq->slot->callback_func = NULL;
+               freq->slot->callback_data = NULL;
+               release_active_slot(freq->slot);
+               freq->slot = NULL;
+       }
+}