"rebase -i": support special-purpose editor to edit insn sheet
[gitweb.git] / daemon.c
index 8dcde73200d1ddbc0dec0dbfdc2f4ff15047abd9..4c8346d5a1fe1325de2dd335a4e61a2dad994211 100644 (file)
--- a/daemon.c
+++ b/daemon.c
@@ -1,9 +1,9 @@
 #include "cache.h"
 #include "pkt-line.h"
 #include "exec_cmd.h"
-#include "interpolate.h"
-
-#include <syslog.h>
+#include "run-command.h"
+#include "strbuf.h"
+#include "string-list.h"
 
 #ifndef HOST_NAME_MAX
 #define HOST_NAME_MAX 256
 #define NI_MAXSERV 32
 #endif
 
+#ifdef NO_INITGROUPS
+#define initgroups(x, y) (0) /* nothing */
+#endif
+
 static int log_syslog;
 static int verbose;
 static int reuseaddr;
-static int child_handler_pipe[2];
 
 static const char daemon_usage[] =
 "git daemon [--verbose] [--syslog] [--export-all]\n"
-"           [--timeout=n] [--init-timeout=n] [--strict-paths]\n"
-"           [--base-path=path] [--base-path-relaxed]\n"
-"           [--user-path | --user-path=path]\n"
-"           [--interpolated-path=path]\n"
-"           [--reuseaddr] [--detach] [--pid-file=file]\n"
-"           [--[enable|disable|allow-override|forbid-override]=service]\n"
-"           [--inetd | [--listen=host_or_ipaddr] [--port=n]\n"
-"                      [--user=user [--group=group]]\n"
-"           [directory...]";
+"           [--timeout=<n>] [--init-timeout=<n>] [--max-connections=<n>]\n"
+"           [--strict-paths] [--base-path=<path>] [--base-path-relaxed]\n"
+"           [--user-path | --user-path=<path>]\n"
+"           [--interpolated-path=<path>]\n"
+"           [--reuseaddr] [--pid-file=<file>]\n"
+"           [--(enable|disable|allow-override|forbid-override)=<service>]\n"
+"           [--inetd | [--listen=<host_or_ipaddr>] [--port=<n>]\n"
+"                      [--detach] [--user=<user> [--group=<group>]]\n"
+"           [<directory>...]";
 
 /* List of acceptable pathname prefixes */
 static char **ok_paths;
@@ -55,63 +58,31 @@ static const char *user_path;
 static unsigned int timeout;
 static unsigned int init_timeout;
 
-/*
- * Static table for now.  Ugh.
- * Feel free to make dynamic as needed.
- */
-#define INTERP_SLOT_HOST       (0)
-#define INTERP_SLOT_CANON_HOST (1)
-#define INTERP_SLOT_IP         (2)
-#define INTERP_SLOT_PORT       (3)
-#define INTERP_SLOT_DIR                (4)
-#define INTERP_SLOT_PERCENT    (5)
-
-static struct interp interp_table[] = {
-       { "%H", 0},
-       { "%CH", 0},
-       { "%IP", 0},
-       { "%P", 0},
-       { "%D", 0},
-       { "%%", 0},
-};
-
+static char *hostname;
+static char *canon_hostname;
+static char *ip_address;
+static char *tcp_port;
 
 static void logreport(int priority, const char *err, va_list params)
 {
-       /* We should do a single write so that it is atomic and output
-        * of several processes do not get intermingled. */
-       char buf[1024];
-       int buflen;
-       int maxlen, msglen;
-
-       /* sizeof(buf) should be big enough for "[pid] \n" */
-       buflen = snprintf(buf, sizeof(buf), "[%ld] ", (long) getpid());
-
-       maxlen = sizeof(buf) - buflen - 1; /* -1 for our own LF */
-       msglen = vsnprintf(buf + buflen, maxlen, err, params);
-
        if (log_syslog) {
+               char buf[1024];
+               vsnprintf(buf, sizeof(buf), err, params);
                syslog(priority, "%s", buf);
-               return;
+       } else {
+               /*
+                * Since stderr is set to buffered mode, the
+                * logging of different processes will not overlap
+                * unless they overflow the (rather big) buffers.
+                */
+               fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
+               vfprintf(stderr, err, params);
+               fputc('\n', stderr);
+               fflush(stderr);
        }
-
-       /* maxlen counted our own LF but also counts space given to
-        * vsnprintf for the terminating NUL.  We want to make sure that
-        * we have space for our own LF and NUL after the "meat" of the
-        * message, so truncate it at maxlen - 1.
-        */
-       if (msglen > maxlen - 1)
-               msglen = maxlen - 1;
-       else if (msglen < 0)
-               msglen = 0; /* Protect against weird return values. */
-       buflen += msglen;
-
-       buf[buflen++] = '\n';
-       buf[buflen] = '\0';
-
-       write_in_full(2, buf, buflen);
 }
 
+__attribute__((format (printf, 1, 2)))
 static void logerror(const char *err, ...)
 {
        va_list params;
@@ -120,6 +91,7 @@ static void logerror(const char *err, ...)
        va_end(params);
 }
 
+__attribute__((format (printf, 1, 2)))
 static void loginfo(const char *err, ...)
 {
        va_list params;
@@ -136,64 +108,16 @@ static void NORETURN daemon_die(const char *err, va_list params)
        exit(1);
 }
 
-static int avoid_alias(char *p)
-{
-       int sl, ndot;
-
-       /*
-        * This resurrects the belts and suspenders paranoia check by HPA
-        * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
-        * does not do getcwd() based path canonicalizations.
-        *
-        * sl becomes true immediately after seeing '/' and continues to
-        * be true as long as dots continue after that without intervening
-        * non-dot character.
-        */
-       if (!p || (*p != '/' && *p != '~'))
-               return -1;
-       sl = 1; ndot = 0;
-       p++;
-
-       while (1) {
-               char ch = *p++;
-               if (sl) {
-                       if (ch == '.')
-                               ndot++;
-                       else if (ch == '/') {
-                               if (ndot < 3)
-                                       /* reject //, /./ and /../ */
-                                       return -1;
-                               ndot = 0;
-                       }
-                       else if (ch == 0) {
-                               if (0 < ndot && ndot < 3)
-                                       /* reject /.$ and /..$ */
-                                       return -1;
-                               return 0;
-                       }
-                       else
-                               sl = ndot = 0;
-               }
-               else if (ch == 0)
-                       return 0;
-               else if (ch == '/') {
-                       sl = 1;
-                       ndot = 0;
-               }
-       }
-}
-
-static char *path_ok(struct interp *itable)
+static char *path_ok(char *directory)
 {
        static char rpath[PATH_MAX];
        static char interp_path[PATH_MAX];
-       int retried_path = 0;
        char *path;
        char *dir;
 
-       dir = itable[INTERP_SLOT_DIR].value;
+       dir = directory;
 
-       if (avoid_alias(dir)) {
+       if (daemon_avoid_alias(dir)) {
                logerror("'%s': aliased", dir);
                return NULL;
        }
@@ -221,14 +145,25 @@ static char *path_ok(struct interp *itable)
                }
        }
        else if (interpolated_path && saw_extended_args) {
+               struct strbuf expanded_path = STRBUF_INIT;
+               struct strbuf_expand_dict_entry dict[6];
+
+               dict[0].placeholder = "H"; dict[0].value = hostname;
+               dict[1].placeholder = "CH"; dict[1].value = canon_hostname;
+               dict[2].placeholder = "IP"; dict[2].value = ip_address;
+               dict[3].placeholder = "P"; dict[3].value = tcp_port;
+               dict[4].placeholder = "D"; dict[4].value = directory;
+               dict[5].placeholder = NULL; dict[5].value = NULL;
                if (*dir != '/') {
                        /* Allow only absolute */
                        logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
                        return NULL;
                }
 
-               interpolate(interp_path, PATH_MAX, interpolated_path,
-                           interp_table, ARRAY_SIZE(interp_table));
+               strbuf_expand(&expanded_path, interpolated_path,
+                               strbuf_expand_dict_cb, &dict);
+               strlcpy(interp_path, expanded_path.buf, PATH_MAX);
+               strbuf_release(&expanded_path);
                loginfo("Interpolated dir '%s'", interp_path);
 
                dir = interp_path;
@@ -243,25 +178,18 @@ static char *path_ok(struct interp *itable)
                dir = rpath;
        }
 
-       do {
-               path = enter_repo(dir, strict_paths);
-               if (path)
-                       break;
-
+       path = enter_repo(dir, strict_paths);
+       if (!path && base_path && base_path_relaxed) {
                /*
                 * if we fail and base_path_relaxed is enabled, try without
                 * prefixing the base path
                 */
-               if (base_path && base_path_relaxed && !retried_path) {
-                       dir = itable[INTERP_SLOT_DIR].value;
-                       retried_path = 1;
-                       continue;
-               }
-               break;
-       } while (1);
+               dir = directory;
+               path = enter_repo(dir, strict_paths);
+       }
 
        if (!path) {
-               logerror("'%s': unable to chdir or not a git archive", dir);
+               logerror("'%s' does not appear to be a git repository", dir);
                return NULL;
        }
 
@@ -319,14 +247,12 @@ static int git_daemon_config(const char *var, const char *value, void *cb)
        return 0;
 }
 
-static int run_service(struct interp *itable, struct daemon_service *service)
+static int run_service(char *dir, struct daemon_service *service)
 {
        const char *path;
        int enabled = service->enabled;
 
-       loginfo("Request %s for '%s'",
-               service->name,
-               itable[INTERP_SLOT_DIR].value);
+       loginfo("Request %s for '%s'", service->name, dir);
 
        if (!enabled && !service->overridable) {
                logerror("'%s': service not enabled.", service->name);
@@ -334,7 +260,7 @@ static int run_service(struct interp *itable, struct daemon_service *service)
                return -1;
        }
 
-       if (!(path = path_ok(itable)))
+       if (!(path = path_ok(dir)))
                return -1;
 
        /*
@@ -377,28 +303,68 @@ static int run_service(struct interp *itable, struct daemon_service *service)
        return service->fn();
 }
 
+static void copy_to_log(int fd)
+{
+       struct strbuf line = STRBUF_INIT;
+       FILE *fp;
+
+       fp = fdopen(fd, "r");
+       if (fp == NULL) {
+               logerror("fdopen of error channel failed");
+               close(fd);
+               return;
+       }
+
+       while (strbuf_getline(&line, fp, '\n') != EOF) {
+               logerror("%s", line.buf);
+               strbuf_setlen(&line, 0);
+       }
+
+       strbuf_release(&line);
+       fclose(fp);
+}
+
+static int run_service_command(const char **argv)
+{
+       struct child_process cld;
+
+       memset(&cld, 0, sizeof(cld));
+       cld.argv = argv;
+       cld.git_cmd = 1;
+       cld.err = -1;
+       if (start_command(&cld))
+               return -1;
+
+       close(0);
+       close(1);
+
+       copy_to_log(cld.err);
+
+       return finish_command(&cld);
+}
+
 static int upload_pack(void)
 {
        /* Timeout as string */
        char timeout_buf[64];
+       const char *argv[] = { "upload-pack", "--strict", NULL, ".", NULL };
 
-       snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
+       argv[2] = timeout_buf;
 
-       /* git-upload-pack only ever reads stuff, so this is safe */
-       execl_git_cmd("upload-pack", "--strict", timeout_buf, ".", NULL);
-       return -1;
+       snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
+       return run_service_command(argv);
 }
 
 static int upload_archive(void)
 {
-       execl_git_cmd("upload-archive", ".", NULL);
-       return -1;
+       static const char *argv[] = { "upload-archive", ".", NULL };
+       return run_service_command(argv);
 }
 
 static int receive_pack(void)
 {
-       execl_git_cmd("receive-pack", ".", NULL);
-       return -1;
+       static const char *argv[] = { "receive-pack", ".", NULL };
+       return run_service_command(argv);
 }
 
 static struct daemon_service daemon_service[] = {
@@ -431,89 +397,110 @@ static void make_service_overridable(const char *name, int ena)
        die("No such service %s", name);
 }
 
+static char *xstrdup_tolower(const char *str)
+{
+       char *p, *dup = xstrdup(str);
+       for (p = dup; *p; p++)
+               *p = tolower(*p);
+       return dup;
+}
+
+static void parse_host_and_port(char *hostport, char **host,
+       char **port)
+{
+       if (*hostport == '[') {
+               char *end;
+
+               end = strchr(hostport, ']');
+               if (!end)
+                       die("Invalid request ('[' without ']')");
+               *end = '\0';
+               *host = hostport + 1;
+               if (!end[1])
+                       *port = NULL;
+               else if (end[1] == ':')
+                       *port = end + 2;
+               else
+                       die("Garbage after end of host part");
+       } else {
+               *host = hostport;
+               *port = strrchr(hostport, ':');
+               if (*port) {
+                       **port = '\0';
+                       ++*port;
+               }
+       }
+}
+
 /*
- * Separate the "extra args" information as supplied by the client connection.
- * Any resulting data is squirreled away in the given interpolation table.
+ * Read the host as supplied by the client connection.
  */
-static void parse_extra_args(struct interp *table, char *extra_args, int buflen)
+static void parse_host_arg(char *extra_args, int buflen)
 {
        char *val;
        int vallen;
        char *end = extra_args + buflen;
 
-       while (extra_args < end && *extra_args) {
+       if (extra_args < end && *extra_args) {
                saw_extended_args = 1;
                if (strncasecmp("host=", extra_args, 5) == 0) {
                        val = extra_args + 5;
                        vallen = strlen(val) + 1;
                        if (*val) {
                                /* Split <host>:<port> at colon. */
-                               char *host = val;
-                               char *port = strrchr(host, ':');
+                               char *host;
+                               char *port;
+                               parse_host_and_port(val, &host, &port);
                                if (port) {
-                                       *port = 0;
-                                       port++;
-                                       interp_set_entry(table, INTERP_SLOT_PORT, port);
+                                       free(tcp_port);
+                                       tcp_port = xstrdup(port);
                                }
-                               interp_set_entry(table, INTERP_SLOT_HOST, host);
+                               free(hostname);
+                               hostname = xstrdup_tolower(host);
                        }
 
                        /* On to the next one */
                        extra_args = val + vallen;
                }
+               if (extra_args < end && *extra_args)
+                       die("Invalid request");
        }
-}
-
-static void fill_in_extra_table_entries(struct interp *itable)
-{
-       char *hp;
-
-       /*
-        * Replace literal host with lowercase-ized hostname.
-        */
-       hp = interp_table[INTERP_SLOT_HOST].value;
-       if (!hp)
-               return;
-       for ( ; *hp; hp++)
-               *hp = tolower(*hp);
 
        /*
         * Locate canonical hostname and its IP address.
         */
+       if (hostname) {
 #ifndef NO_IPV6
-       {
                struct addrinfo hints;
-               struct addrinfo *ai, *ai0;
+               struct addrinfo *ai;
                int gai;
                static char addrbuf[HOST_NAME_MAX + 1];
 
                memset(&hints, 0, sizeof(hints));
                hints.ai_flags = AI_CANONNAME;
 
-               gai = getaddrinfo(interp_table[INTERP_SLOT_HOST].value, 0, &hints, &ai0);
+               gai = getaddrinfo(hostname, NULL, &hints, &ai);
                if (!gai) {
-                       for (ai = ai0; ai; ai = ai->ai_next) {
-                               struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
-
-                               inet_ntop(AF_INET, &sin_addr->sin_addr,
-                                         addrbuf, sizeof(addrbuf));
-                               interp_set_entry(interp_table,
-                                                INTERP_SLOT_CANON_HOST, ai->ai_canonname);
-                               interp_set_entry(interp_table,
-                                                INTERP_SLOT_IP, addrbuf);
-                               break;
-                       }
-                       freeaddrinfo(ai0);
+                       struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
+
+                       inet_ntop(AF_INET, &sin_addr->sin_addr,
+                                 addrbuf, sizeof(addrbuf));
+                       free(ip_address);
+                       ip_address = xstrdup(addrbuf);
+
+                       free(canon_hostname);
+                       canon_hostname = xstrdup(ai->ai_canonname ?
+                                                ai->ai_canonname : ip_address);
+
+                       freeaddrinfo(ai);
                }
-       }
 #else
-       {
                struct hostent *hent;
                struct sockaddr_in sa;
                char **ap;
                static char addrbuf[HOST_NAME_MAX + 1];
 
-               hent = gethostbyname(interp_table[INTERP_SLOT_HOST].value);
+               hent = gethostbyname(hostname);
 
                ap = hent->h_addr_list;
                memset(&sa, 0, sizeof sa);
@@ -524,40 +511,23 @@ static void fill_in_extra_table_entries(struct interp *itable)
                inet_ntop(hent->h_addrtype, &sa.sin_addr,
                          addrbuf, sizeof(addrbuf));
 
-               interp_set_entry(interp_table, INTERP_SLOT_CANON_HOST, hent->h_name);
-               interp_set_entry(interp_table, INTERP_SLOT_IP, addrbuf);
-       }
+               free(canon_hostname);
+               canon_hostname = xstrdup(hent->h_name);
+               free(ip_address);
+               ip_address = xstrdup(addrbuf);
 #endif
+       }
 }
 
 
-static int execute(struct sockaddr *addr)
+static int execute(void)
 {
        static char line[1000];
        int pktlen, len, i;
+       char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
 
-       if (addr) {
-               char addrbuf[256] = "";
-               int port = -1;
-
-               if (addr->sa_family == AF_INET) {
-                       struct sockaddr_in *sin_addr = (void *) addr;
-                       inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
-                       port = ntohs(sin_addr->sin_port);
-#ifndef NO_IPV6
-               } else if (addr && addr->sa_family == AF_INET6) {
-                       struct sockaddr_in6 *sin6_addr = (void *) addr;
-
-                       char *buf = addrbuf;
-                       *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
-                       inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
-                       strcat(buf, "]");
-
-                       port = ntohs(sin6_addr->sin6_port);
-#endif
-               }
-               loginfo("Connection from %s:%d", addrbuf, port);
-       }
+       if (addr)
+               loginfo("Connection from %s:%s", addr, port);
 
        alarm(init_timeout ? init_timeout : timeout);
        pktlen = packet_read_line(0, line, sizeof(line));
@@ -573,16 +543,14 @@ static int execute(struct sockaddr *addr)
                pktlen--;
        }
 
-       /*
-        * Initialize the path interpolation table for this connection.
-        */
-       interp_clear_table(interp_table, ARRAY_SIZE(interp_table));
-       interp_set_entry(interp_table, INTERP_SLOT_PERCENT, "%");
+       free(hostname);
+       free(canon_hostname);
+       free(ip_address);
+       free(tcp_port);
+       hostname = canon_hostname = ip_address = tcp_port = NULL;
 
-       if (len != pktlen) {
-           parse_extra_args(interp_table, line + len + 1, pktlen - len - 1);
-           fill_in_extra_table_entries(interp_table);
-       }
+       if (len != pktlen)
+               parse_host_arg(line + len + 1, pktlen - len - 1);
 
        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
                struct daemon_service *s = &(daemon_service[i]);
@@ -594,9 +562,7 @@ static int execute(struct sockaddr *addr)
                         * Note: The directory here is probably context sensitive,
                         * and might depend on the actual service being performed.
                         */
-                       interp_set_entry(interp_table,
-                                        INTERP_SLOT_DIR, line + namelen + 5);
-                       return run_service(interp_table, s);
+                       return run_service(line + namelen + 5, s);
                }
        }
 
@@ -604,196 +570,151 @@ static int execute(struct sockaddr *addr)
        return -1;
 }
 
+static int addrcmp(const struct sockaddr_storage *s1,
+    const struct sockaddr_storage *s2)
+{
+       const struct sockaddr *sa1 = (const struct sockaddr*) s1;
+       const struct sockaddr *sa2 = (const struct sockaddr*) s2;
+
+       if (sa1->sa_family != sa2->sa_family)
+               return sa1->sa_family - sa2->sa_family;
+       if (sa1->sa_family == AF_INET)
+               return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
+                   &((struct sockaddr_in *)s2)->sin_addr,
+                   sizeof(struct in_addr));
+#ifndef NO_IPV6
+       if (sa1->sa_family == AF_INET6)
+               return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
+                   &((struct sockaddr_in6 *)s2)->sin6_addr,
+                   sizeof(struct in6_addr));
+#endif
+       return 0;
+}
 
-/*
- * We count spawned/reaped separately, just to avoid any
- * races when updating them from signals. The SIGCHLD handler
- * will only update children_reaped, and the fork logic will
- * only update children_spawned.
- *
- * MAX_CHILDREN should be a power-of-two to make the modulus
- * operation cheap. It should also be at least twice
- * the maximum number of connections we will ever allow.
- */
-#define MAX_CHILDREN 128
-
-static int max_connections = 25;
-
-/* These are updated by the signal handler */
-static volatile unsigned int children_reaped;
-static pid_t dead_child[MAX_CHILDREN];
+static int max_connections = 32;
 
-/* These are updated by the main loop */
-static unsigned int children_spawned;
-static unsigned int children_deleted;
+static unsigned int live_children;
 
 static struct child {
-       pid_t pid;
-       int addrlen;
+       struct child *next;
+       struct child_process cld;
        struct sockaddr_storage address;
-} live_child[MAX_CHILDREN];
+} *firstborn;
 
-static void add_child(int idx, pid_t pid, struct sockaddr *addr, int addrlen)
+static void add_child(struct child_process *cld, struct sockaddr *addr, socklen_t addrlen)
 {
-       live_child[idx].pid = pid;
-       live_child[idx].addrlen = addrlen;
-       memcpy(&live_child[idx].address, addr, addrlen);
+       struct child *newborn, **cradle;
+
+       newborn = xcalloc(1, sizeof(*newborn));
+       live_children++;
+       memcpy(&newborn->cld, cld, sizeof(*cld));
+       memcpy(&newborn->address, addr, addrlen);
+       for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
+               if (!addrcmp(&(*cradle)->address, &newborn->address))
+                       break;
+       newborn->next = *cradle;
+       *cradle = newborn;
 }
 
 /*
- * Walk from "deleted" to "spawned", and remove child "pid".
+ * This gets called if the number of connections grows
+ * past "max_connections".
  *
- * We move everything up by one, since the new "deleted" will
- * be one higher.
+ * We kill the newest connection from a duplicate IP.
  */
-static void remove_child(pid_t pid, unsigned deleted, unsigned spawned)
+static void kill_some_child(void)
 {
-       struct child n;
+       const struct child *blanket, *next;
 
-       deleted %= MAX_CHILDREN;
-       spawned %= MAX_CHILDREN;
-       if (live_child[deleted].pid == pid) {
-               live_child[deleted].pid = -1;
+       if (!(blanket = firstborn))
                return;
-       }
-       n = live_child[deleted];
-       for (;;) {
-               struct child m;
-               deleted = (deleted + 1) % MAX_CHILDREN;
-               if (deleted == spawned)
-                       die("could not find dead child %d\n", pid);
-               m = live_child[deleted];
-               live_child[deleted] = n;
-               if (m.pid == pid)
-                       return;
-               n = m;
-       }
-}
 
-/*
- * This gets called if the number of connections grows
- * past "max_connections".
- *
- * We _should_ start off by searching for connections
- * from the same IP, and if there is some address wth
- * multiple connections, we should kill that first.
- *
- * As it is, we just "randomly" kill 25% of the connections,
- * and our pseudo-random generator sucks too. I have no
- * shame.
- *
- * Really, this is just a place-holder for a _real_ algorithm.
- */
-static void kill_some_children(int signo, unsigned start, unsigned stop)
-{
-       start %= MAX_CHILDREN;
-       stop %= MAX_CHILDREN;
-       while (start != stop) {
-               if (!(start & 3))
-                       kill(live_child[start].pid, signo);
-               start = (start + 1) % MAX_CHILDREN;
-       }
+       for (; (next = blanket->next); blanket = next)
+               if (!addrcmp(&blanket->address, &next->address)) {
+                       kill(blanket->cld.pid, SIGTERM);
+                       break;
+               }
 }
 
 static void check_dead_children(void)
 {
-       unsigned spawned, reaped, deleted;
-
-       spawned = children_spawned;
-       reaped = children_reaped;
-       deleted = children_deleted;
-
-       while (deleted < reaped) {
-               pid_t pid = dead_child[deleted % MAX_CHILDREN];
-               const char *dead = pid < 0 ? " (with error)" : "";
-
-               if (pid < 0)
-                       pid = -pid;
-
-               /* XXX: Custom logging, since we don't wanna getpid() */
-               if (verbose) {
-                       if (log_syslog)
-                               syslog(LOG_INFO, "[%d] Disconnected%s",
-                                               pid, dead);
-                       else
-                               fprintf(stderr, "[%d] Disconnected%s\n",
-                                               pid, dead);
-               }
-               remove_child(pid, deleted, spawned);
-               deleted++;
-       }
-       children_deleted = deleted;
+       int status;
+       pid_t pid;
+
+       struct child **cradle, *blanket;
+       for (cradle = &firstborn; (blanket = *cradle);)
+               if ((pid = waitpid(blanket->cld.pid, &status, WNOHANG)) > 1) {
+                       const char *dead = "";
+                       if (status)
+                               dead = " (with error)";
+                       loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
+
+                       /* remove the child */
+                       *cradle = blanket->next;
+                       live_children--;
+                       free(blanket);
+               } else
+                       cradle = &blanket->next;
 }
 
-static void check_max_connections(void)
+static char **cld_argv;
+static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
 {
-       for (;;) {
-               int active;
-               unsigned spawned, deleted;
+       struct child_process cld = { NULL };
+       char addrbuf[300] = "REMOTE_ADDR=", portbuf[300];
+       char *env[] = { addrbuf, portbuf, NULL };
 
+       if (max_connections && live_children >= max_connections) {
+               kill_some_child();
+               sleep(1);  /* give it some time to die */
                check_dead_children();
-
-               spawned = children_spawned;
-               deleted = children_deleted;
-
-               active = spawned - deleted;
-               if (active <= max_connections)
-                       break;
-
-               /* Kill some unstarted connections with SIGTERM */
-               kill_some_children(SIGTERM, deleted, spawned);
-               if (active <= max_connections << 1)
-                       break;
-
-               /* If the SIGTERM thing isn't helping use SIGKILL */
-               kill_some_children(SIGKILL, deleted, spawned);
-               sleep(1);
+               if (live_children >= max_connections) {
+                       close(incoming);
+                       logerror("Too many children, dropping connection");
+                       return;
+               }
        }
-}
-
-static void handle(int incoming, struct sockaddr *addr, int addrlen)
-{
-       pid_t pid = fork();
-
-       if (pid) {
-               unsigned idx;
 
-               close(incoming);
-               if (pid < 0)
-                       return;
+       if (addr->sa_family == AF_INET) {
+               struct sockaddr_in *sin_addr = (void *) addr;
+               inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf + 12,
+                   sizeof(addrbuf) - 12);
+               snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
+                   ntohs(sin_addr->sin_port));
+#ifndef NO_IPV6
+       } else if (addr && addr->sa_family == AF_INET6) {
+               struct sockaddr_in6 *sin6_addr = (void *) addr;
 
-               idx = children_spawned % MAX_CHILDREN;
-               children_spawned++;
-               add_child(idx, pid, addr, addrlen);
+               char *buf = addrbuf + 12;
+               *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
+               inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf,
+                   sizeof(addrbuf) - 13);
+               strcat(buf, "]");
 
-               check_max_connections();
-               return;
+               snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
+                   ntohs(sin6_addr->sin6_port));
+#endif
        }
 
-       dup2(incoming, 0);
-       dup2(incoming, 1);
-       close(incoming);
+       cld.env = (const char **)env;
+       cld.argv = (const char **)cld_argv;
+       cld.in = incoming;
+       cld.out = dup(incoming);
 
-       exit(execute(addr));
+       if (start_command(&cld))
+               logerror("unable to fork");
+       else
+               add_child(&cld, addr, addrlen);
+       close(incoming);
 }
 
 static void child_handler(int signo)
 {
-       for (;;) {
-               int status;
-               pid_t pid = waitpid(-1, &status, WNOHANG);
-
-               if (pid > 0) {
-                       unsigned reaped = children_reaped;
-                       if (!WIFEXITED(status) || WEXITSTATUS(status) > 0)
-                               pid = -pid;
-                       dead_child[reaped % MAX_CHILDREN] = pid;
-                       children_reaped = reaped + 1;
-                       write(child_handler_pipe[1], &status, 1);
-                       continue;
-               }
-               break;
-       }
+       /*
+        * Otherwise empty handler because systemcalls will get interrupted
+        * upon signal receipt
+        * SysV needs the handler to be rearmed
+        */
        signal(SIGCHLD, child_handler);
 }
 
@@ -807,11 +728,17 @@ static int set_reuse_addr(int sockfd)
                          &on, sizeof(on));
 }
 
+struct socketlist {
+       int *list;
+       size_t nr;
+       size_t alloc;
+};
+
 #ifndef NO_IPV6
 
-static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
+static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 {
-       int socknum = 0, *socklist = NULL;
+       int socknum = 0;
        int maxfd = -1;
        char pbuf[NI_MAXSERV];
        struct addrinfo hints, *ai0, *ai;
@@ -826,8 +753,10 @@ static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
        hints.ai_flags = AI_PASSIVE;
 
        gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
-       if (gai)
-               die("getaddrinfo() failed: %s\n", gai_strerror(gai));
+       if (gai) {
+               logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
+               return 0;
+       }
 
        for (ai = ai0; ai; ai = ai->ai_next) {
                int sockfd;
@@ -836,7 +765,7 @@ static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
                if (sockfd < 0)
                        continue;
                if (sockfd >= FD_SETSIZE) {
-                       error("too large socket descriptor.");
+                       logerror("Socket descriptor too large");
                        close(sockfd);
                        continue;
                }
@@ -868,8 +797,9 @@ static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
                if (flags >= 0)
                        fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 
-               socklist = xrealloc(socklist, sizeof(int) * (socknum + 1));
-               socklist[socknum++] = sockfd;
+               ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
+               socklist->list[socklist->nr++] = sockfd;
+               socknum++;
 
                if (maxfd < sockfd)
                        maxfd = sockfd;
@@ -877,13 +807,12 @@ static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 
        freeaddrinfo(ai0);
 
-       *socklist_p = socklist;
        return socknum;
 }
 
 #else /* NO_IPV6 */
 
-static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
+static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 {
        struct sockaddr_in sin;
        int sockfd;
@@ -924,53 +853,69 @@ static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
        if (flags >= 0)
                fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 
-       *socklist_p = xmalloc(sizeof(int));
-       **socklist_p = sockfd;
+       ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
+       socklist->list[socklist->nr++] = sockfd;
        return 1;
 }
 
 #endif
 
-static int service_loop(int socknum, int *socklist)
+static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
+{
+       if (!listen_addr->nr)
+               setup_named_sock(NULL, listen_port, socklist);
+       else {
+               int i, socknum;
+               for (i = 0; i < listen_addr->nr; i++) {
+                       socknum = setup_named_sock(listen_addr->items[i].string,
+                                                  listen_port, socklist);
+
+                       if (socknum == 0)
+                               logerror("unable to allocate any listen sockets for host %s on port %u",
+                                        listen_addr->items[i].string, listen_port);
+               }
+       }
+}
+
+static int service_loop(struct socketlist *socklist)
 {
        struct pollfd *pfd;
        int i;
 
-       if (pipe(child_handler_pipe) < 0)
-               die ("Could not set up pipe for child handler");
-
-       pfd = xcalloc(socknum + 1, sizeof(struct pollfd));
+       pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
 
-       for (i = 0; i < socknum; i++) {
-               pfd[i].fd = socklist[i];
+       for (i = 0; i < socklist->nr; i++) {
+               pfd[i].fd = socklist->list[i];
                pfd[i].events = POLLIN;
        }
-       pfd[socknum].fd = child_handler_pipe[0];
-       pfd[socknum].events = POLLIN;
 
        signal(SIGCHLD, child_handler);
 
        for (;;) {
                int i;
 
-               if (poll(pfd, socknum + 1, -1) < 0) {
+               check_dead_children();
+
+               if (poll(pfd, socklist->nr, -1) < 0) {
                        if (errno != EINTR) {
-                               error("poll failed, resuming: %s",
+                               logerror("Poll failed, resuming: %s",
                                      strerror(errno));
                                sleep(1);
                        }
                        continue;
                }
-               if (pfd[socknum].revents & POLLIN) {
-                       read(child_handler_pipe[0], &i, 1);
-                       check_dead_children();
-               }
 
-               for (i = 0; i < socknum; i++) {
+               for (i = 0; i < socklist->nr; i++) {
                        if (pfd[i].revents & POLLIN) {
-                               struct sockaddr_storage ss;
-                               unsigned int sslen = sizeof(ss);
-                               int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
+                               union {
+                                       struct sockaddr sa;
+                                       struct sockaddr_in sai;
+#ifndef NO_IPV6
+                                       struct sockaddr_in6 sai6;
+#endif
+                               } ss;
+                               socklen_t sslen = sizeof(ss);
+                               int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
                                if (incoming < 0) {
                                        switch (errno) {
                                        case EAGAIN:
@@ -978,10 +923,10 @@ static int service_loop(int socknum, int *socklist)
                                        case ECONNABORTED:
                                                continue;
                                        default:
-                                               die("accept returned %s", strerror(errno));
+                                               die_errno("accept returned");
                                        }
                                }
-                               handle(incoming, (struct sockaddr *)&ss, sslen);
+                               handle(incoming, &ss.sa, sslen);
                        }
                }
        }
@@ -994,82 +939,128 @@ static void sanitize_stdfds(void)
        while (fd != -1 && fd < 2)
                fd = dup(fd);
        if (fd == -1)
-               die("open /dev/null or dup failed: %s", strerror(errno));
+               die_errno("open /dev/null or dup failed");
        if (fd > 2)
                close(fd);
 }
 
+#ifdef NO_POSIX_GOODIES
+
+struct credentials;
+
+static void drop_privileges(struct credentials *cred)
+{
+       /* nothing */
+}
+
+static void daemonize(void)
+{
+       die("--detach not supported on this platform");
+}
+
+static struct credentials *prepare_credentials(const char *user_name,
+    const char *group_name)
+{
+       die("--user not supported on this platform");
+}
+
+#else
+
+struct credentials {
+       struct passwd *pass;
+       gid_t gid;
+};
+
+static void drop_privileges(struct credentials *cred)
+{
+       if (cred && (initgroups(cred->pass->pw_name, cred->gid) ||
+           setgid (cred->gid) || setuid(cred->pass->pw_uid)))
+               die("cannot drop privileges");
+}
+
+static struct credentials *prepare_credentials(const char *user_name,
+    const char *group_name)
+{
+       static struct credentials c;
+
+       c.pass = getpwnam(user_name);
+       if (!c.pass)
+               die("user not found - %s", user_name);
+
+       if (!group_name)
+               c.gid = c.pass->pw_gid;
+       else {
+               struct group *group = getgrnam(group_name);
+               if (!group)
+                       die("group not found - %s", group_name);
+
+               c.gid = group->gr_gid;
+       }
+
+       return &c;
+}
+
 static void daemonize(void)
 {
        switch (fork()) {
                case 0:
                        break;
                case -1:
-                       die("fork failed: %s", strerror(errno));
+                       die_errno("fork failed");
                default:
                        exit(0);
        }
        if (setsid() == -1)
-               die("setsid failed: %s", strerror(errno));
+               die_errno("setsid failed");
        close(0);
        close(1);
        close(2);
        sanitize_stdfds();
 }
+#endif
 
 static void store_pid(const char *path)
 {
        FILE *f = fopen(path, "w");
        if (!f)
-               die("cannot open pid file %s: %s", path, strerror(errno));
-       if (fprintf(f, "%d\n", getpid()) < 0 || fclose(f) != 0)
-               die("failed to write pid file %s: %s", path, strerror(errno));
+               die_errno("cannot open pid file '%s'", path);
+       if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
+               die_errno("failed to write pid file '%s'", path);
 }
 
-static int serve(char *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
+static int serve(struct string_list *listen_addr, int listen_port,
+    struct credentials *cred)
 {
-       int socknum, *socklist;
+       struct socketlist socklist = { NULL, 0, 0 };
 
-       socknum = socksetup(listen_addr, listen_port, &socklist);
-       if (socknum == 0)
-               die("unable to allocate any listen sockets on host %s port %u",
-                   listen_addr, listen_port);
+       socksetup(listen_addr, listen_port, &socklist);
+       if (socklist.nr == 0)
+               die("unable to allocate any listen sockets on port %u",
+                   listen_port);
 
-       if (pass && gid &&
-           (initgroups(pass->pw_name, gid) || setgid (gid) ||
-            setuid(pass->pw_uid)))
-               die("cannot drop privileges");
+       drop_privileges(cred);
 
-       return service_loop(socknum, socklist);
+       return service_loop(&socklist);
 }
 
 int main(int argc, char **argv)
 {
        int listen_port = 0;
-       char *listen_addr = NULL;
-       int inetd_mode = 0;
+       struct string_list listen_addr = STRING_LIST_INIT_NODUP;
+       int serve_mode = 0, inetd_mode = 0;
        const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
        int detach = 0;
-       struct passwd *pass = NULL;
-       struct group *group;
-       gid_t gid = 0;
+       struct credentials *cred = NULL;
        int i;
 
-       /* Without this we cannot rely on waitpid() to tell
-        * what happened to our children.
-        */
-       signal(SIGCHLD, SIG_DFL);
+       git_extract_argv0_path(argv[0]);
 
        for (i = 1; i < argc; i++) {
                char *arg = argv[i];
 
                if (!prefixcmp(arg, "--listen=")) {
-                   char *p = arg + 9;
-                   char *ph = listen_addr = xmalloc(strlen(arg + 9) + 1);
-                   while (*p)
-                       *ph++ = tolower(*p++);
-                   *ph = 0;
-                   continue;
+                       string_list_append(&listen_addr, xstrdup_tolower(arg + 9));
+                       continue;
                }
                if (!prefixcmp(arg, "--port=")) {
                        char *end;
@@ -1080,6 +1071,10 @@ int main(int argc, char **argv)
                                continue;
                        }
                }
+               if (!strcmp(arg, "--serve")) {
+                       serve_mode = 1;
+                       continue;
+               }
                if (!strcmp(arg, "--inetd")) {
                        inetd_mode = 1;
                        log_syslog = 1;
@@ -1105,6 +1100,12 @@ int main(int argc, char **argv)
                        init_timeout = atoi(arg+15);
                        continue;
                }
+               if (!prefixcmp(arg, "--max-connections=")) {
+                       max_connections = atoi(arg+18);
+                       if (max_connections < 0)
+                               max_connections = 0;            /* unlimited */
+                       continue;
+               }
                if (!strcmp(arg, "--strict-paths")) {
                        strict_paths = 1;
                        continue;
@@ -1178,14 +1179,16 @@ int main(int argc, char **argv)
        }
 
        if (log_syslog) {
-               openlog("git-daemon", 0, LOG_DAEMON);
+               openlog("git-daemon", LOG_PID, LOG_DAEMON);
                set_die_routine(daemon_die);
-       }
+       } else
+               /* avoid splitting a message in the middle */
+               setvbuf(stderr, NULL, _IOFBF, 4096);
 
-       if (inetd_mode && (group_name || user_name))
-               die("--user and --group are incompatible with --inetd");
+       if (inetd_mode && (detach || group_name || user_name))
+               die("--detach, --user and --group are incompatible with --inetd");
 
-       if (inetd_mode && (listen_port || listen_addr))
+       if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
                die("--listen= and --port= are incompatible with --inetd");
        else if (listen_port == 0)
                listen_port = DEFAULT_GIT_PORT;
@@ -1193,53 +1196,41 @@ int main(int argc, char **argv)
        if (group_name && !user_name)
                die("--group supplied without --user");
 
-       if (user_name) {
-               pass = getpwnam(user_name);
-               if (!pass)
-                       die("user not found - %s", user_name);
-
-               if (!group_name)
-                       gid = pass->pw_gid;
-               else {
-                       group = getgrnam(group_name);
-                       if (!group)
-                               die("group not found - %s", group_name);
-
-                       gid = group->gr_gid;
-               }
-       }
+       if (user_name)
+               cred = prepare_credentials(user_name, group_name);
 
        if (strict_paths && (!ok_paths || !*ok_paths))
                die("option --strict-paths requires a whitelist");
 
-       if (base_path) {
-               struct stat st;
-
-               if (stat(base_path, &st) || !S_ISDIR(st.st_mode))
-                       die("base-path '%s' does not exist or "
-                           "is not a directory", base_path);
-       }
+       if (base_path && !is_directory(base_path))
+               die("base-path '%s' does not exist or is not a directory",
+                   base_path);
 
        if (inetd_mode) {
-               struct sockaddr_storage ss;
-               struct sockaddr *peer = (struct sockaddr *)&ss;
-               socklen_t slen = sizeof(ss);
-
-               freopen("/dev/null", "w", stderr);
-
-               if (getpeername(0, peer, &slen))
-                       peer = NULL;
-
-               return execute(peer);
+               if (!freopen("/dev/null", "w", stderr))
+                       die_errno("failed to redirect stderr to /dev/null");
        }
 
-       if (detach)
+       if (inetd_mode || serve_mode)
+               return execute();
+
+       if (detach) {
                daemonize();
+               loginfo("Ready to rumble");
+       }
        else
                sanitize_stdfds();
 
        if (pid_file)
                store_pid(pid_file);
 
-       return serve(listen_addr, listen_port, pass, gid);
+       /* prepare argv for serving-processes */
+       cld_argv = xmalloc(sizeof (char *) * (argc + 2));
+       cld_argv[0] = argv[0];  /* git-daemon */
+       cld_argv[1] = "--serve";
+       for (i = 1; i < argc; ++i)
+               cld_argv[i+1] = argv[i];
+       cld_argv[argc+1] = NULL;
+
+       return serve(&listen_addr, listen_port, cred);
 }