imap-send: use parse options API to determine verbosity
[gitweb.git] / builtin / receive-pack.c
index 67ce1ef105d1494e7905e66750b14676e082e11c..32fc540ef3ddfc4d1bb33ae75a0e07b555bdc441 100644 (file)
@@ -1,4 +1,5 @@
 #include "builtin.h"
+#include "lockfile.h"
 #include "pack.h"
 #include "refs.h"
 #include "pkt-line.h"
 #include "string-list.h"
 #include "sha1-array.h"
 #include "connected.h"
+#include "argv-array.h"
 #include "version.h"
+#include "tag.h"
+#include "gpg-interface.h"
+#include "sigchain.h"
 
 static const char receive_pack_usage[] = "git receive-pack <git-dir>";
 
@@ -40,9 +45,27 @@ static int prefer_ofs_delta = 1;
 static int auto_update_server_info;
 static int auto_gc = 1;
 static int fix_thin = 1;
+static int stateless_rpc;
+static const char *service_dir;
 static const char *head_name;
 static void *head_name_to_free;
 static int sent_capabilities;
+static int shallow_update;
+static const char *alt_shallow_file;
+static struct strbuf push_cert = STRBUF_INIT;
+static unsigned char push_cert_sha1[20];
+static struct signature_check sigcheck;
+static const char *push_cert_nonce;
+static const char *cert_nonce_seed;
+
+static const char *NONCE_UNSOLICITED = "UNSOLICITED";
+static const char *NONCE_BAD = "BAD";
+static const char *NONCE_MISSING = "MISSING";
+static const char *NONCE_OK = "OK";
+static const char *NONCE_SLOP = "SLOP";
+static const char *nonce_status;
+static long nonce_stamp_slop;
+static unsigned long nonce_stamp_slop_limit;
 
 static enum deny_action parse_deny_action(const char *var, const char *value)
 {
@@ -121,6 +144,19 @@ static int receive_pack_config(const char *var, const char *value, void *cb)
                return 0;
        }
 
+       if (strcmp(var, "receive.shallowupdate") == 0) {
+               shallow_update = git_config_bool(var, value);
+               return 0;
+       }
+
+       if (strcmp(var, "receive.certnonceseed") == 0)
+               return git_config_string(&cert_nonce_seed, var, value);
+
+       if (strcmp(var, "receive.certnonceslop") == 0) {
+               nonce_stamp_slop_limit = git_config_ulong(var, value);
+               return 0;
+       }
+
        return git_default_config(var, value, cb);
 }
 
@@ -129,15 +165,23 @@ static void show_ref(const char *path, const unsigned char *sha1)
        if (ref_is_hidden(path))
                return;
 
-       if (sent_capabilities)
+       if (sent_capabilities) {
                packet_write(1, "%s %s\n", sha1_to_hex(sha1), path);
-       else
-               packet_write(1, "%s %s%c%s%s agent=%s\n",
-                            sha1_to_hex(sha1), path, 0,
-                            " report-status delete-refs side-band-64k quiet",
-                            prefer_ofs_delta ? " ofs-delta" : "",
-                            git_user_agent_sanitized());
-       sent_capabilities = 1;
+       } else {
+               struct strbuf cap = STRBUF_INIT;
+
+               strbuf_addstr(&cap,
+                             "report-status delete-refs side-band-64k quiet");
+               if (prefer_ofs_delta)
+                       strbuf_addstr(&cap, " ofs-delta");
+               if (push_cert_nonce)
+                       strbuf_addf(&cap, " push-cert=%s", push_cert_nonce);
+               strbuf_addf(&cap, " agent=%s", git_user_agent_sanitized());
+               packet_write(1, "%s %s%c%s\n",
+                            sha1_to_hex(sha1), path, 0, cap.buf);
+               strbuf_release(&cap);
+               sent_capabilities = 1;
+       }
 }
 
 static int show_ref_cb(const char *path, const unsigned char *sha1, int flag, void *unused)
@@ -178,6 +222,8 @@ static void write_head_info(void)
        if (!sent_capabilities)
                show_ref("capabilities^{}", null_sha1);
 
+       advertise_shallow_grafts(1);
+
        /* EOF */
        packet_flush(1);
 }
@@ -187,6 +233,7 @@ struct command {
        const char *error_string;
        unsigned int skip_update:1,
                     did_not_exist:1;
+       int index;
        unsigned char old_sha1[20];
        unsigned char new_sha1[20];
        char ref_name[FLEX_ARRAY]; /* more */
@@ -241,10 +288,231 @@ static int copy_to_sideband(int in, int out, void *arg)
        return 0;
 }
 
+#define HMAC_BLOCK_SIZE 64
+
+static void hmac_sha1(unsigned char *out,
+                     const char *key_in, size_t key_len,
+                     const char *text, size_t text_len)
+{
+       unsigned char key[HMAC_BLOCK_SIZE];
+       unsigned char k_ipad[HMAC_BLOCK_SIZE];
+       unsigned char k_opad[HMAC_BLOCK_SIZE];
+       int i;
+       git_SHA_CTX ctx;
+
+       /* RFC 2104 2. (1) */
+       memset(key, '\0', HMAC_BLOCK_SIZE);
+       if (HMAC_BLOCK_SIZE < key_len) {
+               git_SHA1_Init(&ctx);
+               git_SHA1_Update(&ctx, key_in, key_len);
+               git_SHA1_Final(key, &ctx);
+       } else {
+               memcpy(key, key_in, key_len);
+       }
+
+       /* RFC 2104 2. (2) & (5) */
+       for (i = 0; i < sizeof(key); i++) {
+               k_ipad[i] = key[i] ^ 0x36;
+               k_opad[i] = key[i] ^ 0x5c;
+       }
+
+       /* RFC 2104 2. (3) & (4) */
+       git_SHA1_Init(&ctx);
+       git_SHA1_Update(&ctx, k_ipad, sizeof(k_ipad));
+       git_SHA1_Update(&ctx, text, text_len);
+       git_SHA1_Final(out, &ctx);
+
+       /* RFC 2104 2. (6) & (7) */
+       git_SHA1_Init(&ctx);
+       git_SHA1_Update(&ctx, k_opad, sizeof(k_opad));
+       git_SHA1_Update(&ctx, out, 20);
+       git_SHA1_Final(out, &ctx);
+}
+
+static char *prepare_push_cert_nonce(const char *path, unsigned long stamp)
+{
+       struct strbuf buf = STRBUF_INIT;
+       unsigned char sha1[20];
+
+       strbuf_addf(&buf, "%s:%lu", path, stamp);
+       hmac_sha1(sha1, buf.buf, buf.len, cert_nonce_seed, strlen(cert_nonce_seed));;
+       strbuf_release(&buf);
+
+       /* RFC 2104 5. HMAC-SHA1-80 */
+       strbuf_addf(&buf, "%lu-%.*s", stamp, 20, sha1_to_hex(sha1));
+       return strbuf_detach(&buf, NULL);
+}
+
+/*
+ * NEEDSWORK: reuse find_commit_header() from jk/commit-author-parsing
+ * after dropping "_commit" from its name and possibly moving it out
+ * of commit.c
+ */
+static char *find_header(const char *msg, size_t len, const char *key)
+{
+       int key_len = strlen(key);
+       const char *line = msg;
+
+       while (line && line < msg + len) {
+               const char *eol = strchrnul(line, '\n');
+
+               if ((msg + len <= eol) || line == eol)
+                       return NULL;
+               if (line + key_len < eol &&
+                   !memcmp(line, key, key_len) && line[key_len] == ' ') {
+                       int offset = key_len + 1;
+                       return xmemdupz(line + offset, (eol - line) - offset);
+               }
+               line = *eol ? eol + 1 : NULL;
+       }
+       return NULL;
+}
+
+static const char *check_nonce(const char *buf, size_t len)
+{
+       char *nonce = find_header(buf, len, "nonce");
+       unsigned long stamp, ostamp;
+       char *bohmac, *expect = NULL;
+       const char *retval = NONCE_BAD;
+
+       if (!nonce) {
+               retval = NONCE_MISSING;
+               goto leave;
+       } else if (!push_cert_nonce) {
+               retval = NONCE_UNSOLICITED;
+               goto leave;
+       } else if (!strcmp(push_cert_nonce, nonce)) {
+               retval = NONCE_OK;
+               goto leave;
+       }
+
+       if (!stateless_rpc) {
+               /* returned nonce MUST match what we gave out earlier */
+               retval = NONCE_BAD;
+               goto leave;
+       }
+
+       /*
+        * In stateless mode, we may be receiving a nonce issued by
+        * another instance of the server that serving the same
+        * repository, and the timestamps may not match, but the
+        * nonce-seed and dir should match, so we can recompute and
+        * report the time slop.
+        *
+        * In addition, when a nonce issued by another instance has
+        * timestamp within receive.certnonceslop seconds, we pretend
+        * as if we issued that nonce when reporting to the hook.
+        */
+
+       /* nonce is concat(<seconds-since-epoch>, "-", <hmac>) */
+       if (*nonce <= '0' || '9' < *nonce) {
+               retval = NONCE_BAD;
+               goto leave;
+       }
+       stamp = strtoul(nonce, &bohmac, 10);
+       if (bohmac == nonce || bohmac[0] != '-') {
+               retval = NONCE_BAD;
+               goto leave;
+       }
+
+       expect = prepare_push_cert_nonce(service_dir, stamp);
+       if (strcmp(expect, nonce)) {
+               /* Not what we would have signed earlier */
+               retval = NONCE_BAD;
+               goto leave;
+       }
+
+       /*
+        * By how many seconds is this nonce stale?  Negative value
+        * would mean it was issued by another server with its clock
+        * skewed in the future.
+        */
+       ostamp = strtoul(push_cert_nonce, NULL, 10);
+       nonce_stamp_slop = (long)ostamp - (long)stamp;
+
+       if (nonce_stamp_slop_limit &&
+           abs(nonce_stamp_slop) <= nonce_stamp_slop_limit) {
+               /*
+                * Pretend as if the received nonce (which passes the
+                * HMAC check, so it is not a forged by third-party)
+                * is what we issued.
+                */
+               free((void *)push_cert_nonce);
+               push_cert_nonce = xstrdup(nonce);
+               retval = NONCE_OK;
+       } else {
+               retval = NONCE_SLOP;
+       }
+
+leave:
+       free(nonce);
+       free(expect);
+       return retval;
+}
+
+static void prepare_push_cert_sha1(struct child_process *proc)
+{
+       static int already_done;
+
+       if (!push_cert.len)
+               return;
+
+       if (!already_done) {
+               struct strbuf gpg_output = STRBUF_INIT;
+               struct strbuf gpg_status = STRBUF_INIT;
+               int bogs /* beginning_of_gpg_sig */;
+
+               already_done = 1;
+               if (write_sha1_file(push_cert.buf, push_cert.len, "blob", push_cert_sha1))
+                       hashclr(push_cert_sha1);
+
+               memset(&sigcheck, '\0', sizeof(sigcheck));
+               sigcheck.result = 'N';
+
+               bogs = parse_signature(push_cert.buf, push_cert.len);
+               if (verify_signed_buffer(push_cert.buf, bogs,
+                                        push_cert.buf + bogs, push_cert.len - bogs,
+                                        &gpg_output, &gpg_status) < 0) {
+                       ; /* error running gpg */
+               } else {
+                       sigcheck.payload = push_cert.buf;
+                       sigcheck.gpg_output = gpg_output.buf;
+                       sigcheck.gpg_status = gpg_status.buf;
+                       parse_gpg_output(&sigcheck);
+               }
+
+               strbuf_release(&gpg_output);
+               strbuf_release(&gpg_status);
+               nonce_status = check_nonce(push_cert.buf, bogs);
+       }
+       if (!is_null_sha1(push_cert_sha1)) {
+               argv_array_pushf(&proc->env_array, "GIT_PUSH_CERT=%s",
+                                sha1_to_hex(push_cert_sha1));
+               argv_array_pushf(&proc->env_array, "GIT_PUSH_CERT_SIGNER=%s",
+                                sigcheck.signer ? sigcheck.signer : "");
+               argv_array_pushf(&proc->env_array, "GIT_PUSH_CERT_KEY=%s",
+                                sigcheck.key ? sigcheck.key : "");
+               argv_array_pushf(&proc->env_array, "GIT_PUSH_CERT_STATUS=%c",
+                                sigcheck.result);
+               if (push_cert_nonce) {
+                       argv_array_pushf(&proc->env_array,
+                                        "GIT_PUSH_CERT_NONCE=%s",
+                                        push_cert_nonce);
+                       argv_array_pushf(&proc->env_array,
+                                        "GIT_PUSH_CERT_NONCE_STATUS=%s",
+                                        nonce_status);
+                       if (nonce_status == NONCE_SLOP)
+                               argv_array_pushf(&proc->env_array,
+                                                "GIT_PUSH_CERT_NONCE_SLOP=%ld",
+                                                nonce_stamp_slop);
+               }
+       }
+}
+
 typedef int (*feed_fn)(void *, const char **, size_t *);
 static int run_and_feed_hook(const char *hook_name, feed_fn feed, void *feed_state)
 {
-       struct child_process proc;
+       struct child_process proc = CHILD_PROCESS_INIT;
        struct async muxer;
        const char *argv[2];
        int code;
@@ -255,7 +523,6 @@ static int run_and_feed_hook(const char *hook_name, feed_fn feed, void *feed_sta
 
        argv[1] = NULL;
 
-       memset(&proc, 0, sizeof(proc));
        proc.argv = argv;
        proc.in = -1;
        proc.stdout_to_stderr = 1;
@@ -270,6 +537,8 @@ static int run_and_feed_hook(const char *hook_name, feed_fn feed, void *feed_sta
                proc.err = muxer.in;
        }
 
+       prepare_push_cert_sha1(&proc);
+
        code = start_command(&proc);
        if (code) {
                if (use_sideband)
@@ -277,6 +546,8 @@ static int run_and_feed_hook(const char *hook_name, feed_fn feed, void *feed_sta
                return code;
        }
 
+       sigchain_push(SIGPIPE, SIG_IGN);
+
        while (1) {
                const char *buf;
                size_t n;
@@ -288,6 +559,9 @@ static int run_and_feed_hook(const char *hook_name, feed_fn feed, void *feed_sta
        close(proc.in);
        if (use_sideband)
                finish_async(&muxer);
+
+       sigchain_pop(SIGPIPE);
+
        return finish_command(&proc);
 }
 
@@ -339,7 +613,7 @@ static int run_receive_hook(struct command *commands, const char *hook_name,
 static int run_update_hook(struct command *cmd)
 {
        const char *argv[5];
-       struct child_process proc;
+       struct child_process proc = CHILD_PROCESS_INIT;
        int code;
 
        argv[0] = find_hook("update");
@@ -351,7 +625,6 @@ static int run_update_hook(struct command *cmd)
        argv[3] = sha1_to_hex(cmd->new_sha1);
        argv[4] = NULL;
 
-       memset(&proc, 0, sizeof(proc));
        proc.no_stdin = 1;
        proc.stdout_to_stderr = 1;
        proc.err = use_sideband ? -1 : 0;
@@ -418,17 +691,55 @@ static void refuse_unconfigured_deny_delete_current(void)
                rp_error("%s", refuse_unconfigured_deny_delete_current_msg[i]);
 }
 
-static const char *update(struct command *cmd)
+static int command_singleton_iterator(void *cb_data, unsigned char sha1[20]);
+static int update_shallow_ref(struct command *cmd, struct shallow_info *si)
+{
+       static struct lock_file shallow_lock;
+       struct sha1_array extra = SHA1_ARRAY_INIT;
+       const char *alt_file;
+       uint32_t mask = 1 << (cmd->index % 32);
+       int i;
+
+       trace_printf_key(&trace_shallow,
+                        "shallow: update_shallow_ref %s\n", cmd->ref_name);
+       for (i = 0; i < si->shallow->nr; i++)
+               if (si->used_shallow[i] &&
+                   (si->used_shallow[i][cmd->index / 32] & mask) &&
+                   !delayed_reachability_test(si, i))
+                       sha1_array_append(&extra, si->shallow->sha1[i]);
+
+       setup_alternate_shallow(&shallow_lock, &alt_file, &extra);
+       if (check_shallow_connected(command_singleton_iterator,
+                                   0, cmd, alt_file)) {
+               rollback_lock_file(&shallow_lock);
+               sha1_array_clear(&extra);
+               return -1;
+       }
+
+       commit_lock_file(&shallow_lock);
+
+       /*
+        * Make sure setup_alternate_shallow() for the next ref does
+        * not lose these new roots..
+        */
+       for (i = 0; i < extra.nr; i++)
+               register_shallow(extra.sha1[i]);
+
+       si->shallow_ref[cmd->index] = 0;
+       sha1_array_clear(&extra);
+       return 0;
+}
+
+static const char *update(struct command *cmd, struct shallow_info *si)
 {
        const char *name = cmd->ref_name;
        struct strbuf namespaced_name_buf = STRBUF_INIT;
        const char *namespaced_name;
        unsigned char *old_sha1 = cmd->old_sha1;
        unsigned char *new_sha1 = cmd->new_sha1;
-       struct ref_lock *lock;
 
        /* only refs/... are allowed */
-       if (prefixcmp(name, "refs/") || check_refname_format(name + 5, 0)) {
+       if (!starts_with(name, "refs/") || check_refname_format(name + 5, 0)) {
                rp_error("refusing to create funny ref '%s' remotely", name);
                return "funny refname";
        }
@@ -459,7 +770,7 @@ static const char *update(struct command *cmd)
        }
 
        if (!is_null_sha1(old_sha1) && is_null_sha1(new_sha1)) {
-               if (deny_deletes && !prefixcmp(name, "refs/heads/")) {
+               if (deny_deletes && starts_with(name, "refs/heads/")) {
                        rp_error("denying ref deletion for %s", name);
                        return "deletion prohibited";
                }
@@ -483,7 +794,7 @@ static const char *update(struct command *cmd)
 
        if (deny_non_fast_forwards && !is_null_sha1(new_sha1) &&
            !is_null_sha1(old_sha1) &&
-           !prefixcmp(name, "refs/heads/")) {
+           starts_with(name, "refs/heads/")) {
                struct object *old_object, *new_object;
                struct commit *old_commit, *new_commit;
 
@@ -526,15 +837,28 @@ static const char *update(struct command *cmd)
                return NULL; /* good */
        }
        else {
-               lock = lock_any_ref_for_update(namespaced_name, old_sha1,
-                                              0, NULL);
-               if (!lock) {
-                       rp_error("failed to lock %s", name);
-                       return "failed to lock";
-               }
-               if (write_ref_sha1(lock, new_sha1, "push")) {
-                       return "failed to write"; /* error() already called */
+               struct strbuf err = STRBUF_INIT;
+               struct ref_transaction *transaction;
+
+               if (shallow_update && si->shallow_ref[cmd->index] &&
+                   update_shallow_ref(cmd, si))
+                       return "shallow error";
+
+               transaction = ref_transaction_begin(&err);
+               if (!transaction ||
+                   ref_transaction_update(transaction, namespaced_name,
+                                          new_sha1, old_sha1, 0, 1, "push",
+                                          &err) ||
+                   ref_transaction_commit(transaction, &err)) {
+                       ref_transaction_free(transaction);
+
+                       rp_error("%s", err.buf);
+                       strbuf_release(&err);
+                       return "failed to update ref";
                }
+
+               ref_transaction_free(transaction);
+               strbuf_release(&err);
                return NULL; /* good */
        }
 }
@@ -544,7 +868,7 @@ static void run_update_post_hook(struct command *commands)
        struct command *cmd;
        int argc;
        const char **argv;
-       struct child_process proc;
+       struct child_process proc = CHILD_PROCESS_INIT;
        char *hook;
 
        hook = find_hook("post-update");
@@ -560,17 +884,13 @@ static void run_update_post_hook(struct command *commands)
        argv[0] = hook;
 
        for (argc = 1, cmd = commands; cmd; cmd = cmd->next) {
-               char *p;
                if (cmd->error_string || cmd->did_not_exist)
                        continue;
-               p = xmalloc(strlen(cmd->ref_name) + 1);
-               strcpy(p, cmd->ref_name);
-               argv[argc] = p;
+               argv[argc] = xstrdup(cmd->ref_name);
                argc++;
        }
        argv[argc] = NULL;
 
-       memset(&proc, 0, sizeof(proc));
        proc.no_stdin = 1;
        proc.stdout_to_stderr = 1;
        proc.err = use_sideband ? -1 : 0;
@@ -594,7 +914,7 @@ static void check_aliased_update(struct command *cmd, struct string_list *list)
        int flag;
 
        strbuf_addf(&buf, "%s%s", get_git_namespace(), cmd->ref_name);
-       dst_name = resolve_ref_unsafe(buf.buf, sha1, 0, &flag);
+       dst_name = resolve_ref_unsafe(buf.buf, 0, sha1, &flag);
        strbuf_release(&buf);
 
        if (!(flag & REF_ISSYMREF))
@@ -666,12 +986,16 @@ static int command_singleton_iterator(void *cb_data, unsigned char sha1[20])
        return 0;
 }
 
-static void set_connectivity_errors(struct command *commands)
+static void set_connectivity_errors(struct command *commands,
+                                   struct shallow_info *si)
 {
        struct command *cmd;
 
        for (cmd = commands; cmd; cmd = cmd->next) {
                struct command *singleton = cmd;
+               if (shallow_update && si->shallow_ref[cmd->index])
+                       /* to be checked in update_shallow_ref() */
+                       continue;
                if (!check_everything_connected(command_singleton_iterator,
                                                0, &singleton))
                        continue;
@@ -679,18 +1003,26 @@ static void set_connectivity_errors(struct command *commands)
        }
 }
 
+struct iterate_data {
+       struct command *cmds;
+       struct shallow_info *si;
+};
+
 static int iterate_receive_command_list(void *cb_data, unsigned char sha1[20])
 {
-       struct command **cmd_list = cb_data;
+       struct iterate_data *data = cb_data;
+       struct command **cmd_list = &data->cmds;
        struct command *cmd = *cmd_list;
 
-       while (cmd) {
-               if (!is_null_sha1(cmd->new_sha1)) {
+       for (; cmd; cmd = cmd->next) {
+               if (shallow_update && data->si->shallow_ref[cmd->index])
+                       /* to be checked in update_shallow_ref() */
+                       continue;
+               if (!is_null_sha1(cmd->new_sha1) && !cmd->skip_update) {
                        hashcpy(sha1, cmd->new_sha1);
                        *cmd_list = cmd->next;
                        return 0;
                }
-               cmd = cmd->next;
        }
        *cmd_list = NULL;
        return -1; /* end of list */
@@ -710,10 +1042,14 @@ static void reject_updates_to_hidden(struct command *commands)
        }
 }
 
-static void execute_commands(struct command *commands, const char *unpacker_error)
+static void execute_commands(struct command *commands,
+                            const char *unpacker_error,
+                            struct shallow_info *si)
 {
+       int checked_connectivity;
        struct command *cmd;
        unsigned char sha1[20];
+       struct iterate_data data;
 
        if (unpacker_error) {
                for (cmd = commands; cmd; cmd = cmd->next)
@@ -721,10 +1057,10 @@ static void execute_commands(struct command *commands, const char *unpacker_erro
                return;
        }
 
-       cmd = commands;
-       if (check_everything_connected(iterate_receive_command_list,
-                                      0, &cmd))
-               set_connectivity_errors(commands);
+       data.cmds = commands;
+       data.si = si;
+       if (check_everything_connected(iterate_receive_command_list, 0, &data))
+               set_connectivity_errors(commands, si);
 
        reject_updates_to_hidden(commands);
 
@@ -739,8 +1075,9 @@ static void execute_commands(struct command *commands, const char *unpacker_erro
        check_aliased_updates(commands);
 
        free(head_name_to_free);
-       head_name = head_name_to_free = resolve_refdup("HEAD", sha1, 0, NULL);
+       head_name = head_name_to_free = resolve_refdup("HEAD", 0, sha1, NULL);
 
+       checked_connectivity = 1;
        for (cmd = commands; cmd; cmd = cmd->next) {
                if (cmd->error_string)
                        continue;
@@ -748,36 +1085,94 @@ static void execute_commands(struct command *commands, const char *unpacker_erro
                if (cmd->skip_update)
                        continue;
 
-               cmd->error_string = update(cmd);
+               cmd->error_string = update(cmd, si);
+               if (shallow_update && !cmd->error_string &&
+                   si->shallow_ref[cmd->index]) {
+                       error("BUG: connectivity check has not been run on ref %s",
+                             cmd->ref_name);
+                       checked_connectivity = 0;
+               }
        }
+
+       if (shallow_update && !checked_connectivity)
+               error("BUG: run 'git fsck' for safety.\n"
+                     "If there are errors, try to remove "
+                     "the reported refs above");
 }
 
-static struct command *read_head_info(void)
+static struct command **queue_command(struct command **tail,
+                                     const char *line,
+                                     int linelen)
+{
+       unsigned char old_sha1[20], new_sha1[20];
+       struct command *cmd;
+       const char *refname;
+       int reflen;
+
+       if (linelen < 83 ||
+           line[40] != ' ' ||
+           line[81] != ' ' ||
+           get_sha1_hex(line, old_sha1) ||
+           get_sha1_hex(line + 41, new_sha1))
+               die("protocol error: expected old/new/ref, got '%s'", line);
+
+       refname = line + 82;
+       reflen = linelen - 82;
+       cmd = xcalloc(1, sizeof(struct command) + reflen + 1);
+       hashcpy(cmd->old_sha1, old_sha1);
+       hashcpy(cmd->new_sha1, new_sha1);
+       memcpy(cmd->ref_name, refname, reflen);
+       cmd->ref_name[reflen] = '\0';
+       *tail = cmd;
+       return &cmd->next;
+}
+
+static void queue_commands_from_cert(struct command **tail,
+                                    struct strbuf *push_cert)
+{
+       const char *boc, *eoc;
+
+       if (*tail)
+               die("protocol error: got both push certificate and unsigned commands");
+
+       boc = strstr(push_cert->buf, "\n\n");
+       if (!boc)
+               die("malformed push certificate %.*s", 100, push_cert->buf);
+       else
+               boc += 2;
+       eoc = push_cert->buf + parse_signature(push_cert->buf, push_cert->len);
+
+       while (boc < eoc) {
+               const char *eol = memchr(boc, '\n', eoc - boc);
+               tail = queue_command(tail, boc, eol ? eol - boc : eoc - eol);
+               boc = eol ? eol + 1 : eoc;
+       }
+}
+
+static struct command *read_head_info(struct sha1_array *shallow)
 {
        struct command *commands = NULL;
        struct command **p = &commands;
        for (;;) {
                char *line;
-               unsigned char old_sha1[20], new_sha1[20];
-               struct command *cmd;
-               char *refname;
-               int len, reflen;
+               int len, linelen;
 
                line = packet_read_line(0, &len);
                if (!line)
                        break;
-               if (len < 83 ||
-                   line[40] != ' ' ||
-                   line[81] != ' ' ||
-                   get_sha1_hex(line, old_sha1) ||
-                   get_sha1_hex(line + 41, new_sha1))
-                       die("protocol error: expected old/new/ref, got '%s'",
-                           line);
-
-               refname = line + 82;
-               reflen = strlen(refname);
-               if (reflen + 82 < len) {
-                       const char *feature_list = refname + reflen + 1;
+
+               if (len == 48 && starts_with(line, "shallow ")) {
+                       unsigned char sha1[20];
+                       if (get_sha1_hex(line + 8, sha1))
+                               die("protocol error: expected shallow sha, got '%s'",
+                                   line + 8);
+                       sha1_array_append(shallow, sha1);
+                       continue;
+               }
+
+               linelen = strlen(line);
+               if (linelen < len) {
+                       const char *feature_list = line + linelen + 1;
                        if (parse_feature_request(feature_list, "report-status"))
                                report_status = 1;
                        if (parse_feature_request(feature_list, "side-band-64k"))
@@ -785,13 +1180,34 @@ static struct command *read_head_info(void)
                        if (parse_feature_request(feature_list, "quiet"))
                                quiet = 1;
                }
-               cmd = xcalloc(1, sizeof(struct command) + len - 80);
-               hashcpy(cmd->old_sha1, old_sha1);
-               hashcpy(cmd->new_sha1, new_sha1);
-               memcpy(cmd->ref_name, line + 82, len - 81);
-               *p = cmd;
-               p = &cmd->next;
+
+               if (!strcmp(line, "push-cert")) {
+                       int true_flush = 0;
+                       char certbuf[1024];
+
+                       for (;;) {
+                               len = packet_read(0, NULL, NULL,
+                                                 certbuf, sizeof(certbuf), 0);
+                               if (!len) {
+                                       true_flush = 1;
+                                       break;
+                               }
+                               if (!strcmp(certbuf, "push-cert-end\n"))
+                                       break; /* end of cert */
+                               strbuf_addstr(&push_cert, certbuf);
+                       }
+
+                       if (true_flush)
+                               break;
+                       continue;
+               }
+
+               p = queue_command(p, line, linelen);
        }
+
+       if (push_cert.len)
+               queue_commands_from_cert(p, &push_cert);
+
        return commands;
 }
 
@@ -817,11 +1233,13 @@ static const char *parse_pack_header(struct pack_header *hdr)
 
 static const char *pack_lockfile;
 
-static const char *unpack(int err_fd)
+static const char *unpack(int err_fd, struct shallow_info *si)
 {
        struct pack_header hdr;
        const char *hdr_err;
+       int status;
        char hdr_arg[38];
+       struct child_process child = CHILD_PROCESS_INIT;
        int fsck_objects = (receive_fsck_objects >= 0
                            ? receive_fsck_objects
                            : transfer_fsck_objects >= 0
@@ -838,72 +1256,61 @@ static const char *unpack(int err_fd)
                        "--pack_header=%"PRIu32",%"PRIu32,
                        ntohl(hdr.hdr_version), ntohl(hdr.hdr_entries));
 
+       if (si->nr_ours || si->nr_theirs) {
+               alt_shallow_file = setup_temporary_shallow(si->shallow);
+               argv_array_push(&child.args, "--shallow-file");
+               argv_array_push(&child.args, alt_shallow_file);
+       }
+
        if (ntohl(hdr.hdr_entries) < unpack_limit) {
-               int code, i = 0;
-               struct child_process child;
-               const char *unpacker[5];
-               unpacker[i++] = "unpack-objects";
+               argv_array_pushl(&child.args, "unpack-objects", hdr_arg, NULL);
                if (quiet)
-                       unpacker[i++] = "-q";
+                       argv_array_push(&child.args, "-q");
                if (fsck_objects)
-                       unpacker[i++] = "--strict";
-               unpacker[i++] = hdr_arg;
-               unpacker[i++] = NULL;
-               memset(&child, 0, sizeof(child));
-               child.argv = unpacker;
+                       argv_array_push(&child.args, "--strict");
                child.no_stdout = 1;
                child.err = err_fd;
                child.git_cmd = 1;
-               code = run_command(&child);
-               if (!code)
-                       return NULL;
-               return "unpack-objects abnormal exit";
+               status = run_command(&child);
+               if (status)
+                       return "unpack-objects abnormal exit";
        } else {
-               const char *keeper[7];
-               int s, status, i = 0;
+               int s;
                char keep_arg[256];
-               struct child_process ip;
 
                s = sprintf(keep_arg, "--keep=receive-pack %"PRIuMAX" on ", (uintmax_t) getpid());
                if (gethostname(keep_arg + s, sizeof(keep_arg) - s))
                        strcpy(keep_arg + s, "localhost");
 
-               keeper[i++] = "index-pack";
-               keeper[i++] = "--stdin";
+               argv_array_pushl(&child.args, "index-pack",
+                                "--stdin", hdr_arg, keep_arg, NULL);
                if (fsck_objects)
-                       keeper[i++] = "--strict";
+                       argv_array_push(&child.args, "--strict");
                if (fix_thin)
-                       keeper[i++] = "--fix-thin";
-               keeper[i++] = hdr_arg;
-               keeper[i++] = keep_arg;
-               keeper[i++] = NULL;
-               memset(&ip, 0, sizeof(ip));
-               ip.argv = keeper;
-               ip.out = -1;
-               ip.err = err_fd;
-               ip.git_cmd = 1;
-               status = start_command(&ip);
-               if (status) {
+                       argv_array_push(&child.args, "--fix-thin");
+               child.out = -1;
+               child.err = err_fd;
+               child.git_cmd = 1;
+               status = start_command(&child);
+               if (status)
                        return "index-pack fork failed";
-               }
-               pack_lockfile = index_pack_lockfile(ip.out);
-               close(ip.out);
-               status = finish_command(&ip);
-               if (!status) {
-                       reprepare_packed_git();
-                       return NULL;
-               }
-               return "index-pack abnormal exit";
+               pack_lockfile = index_pack_lockfile(child.out);
+               close(child.out);
+               status = finish_command(&child);
+               if (status)
+                       return "index-pack abnormal exit";
+               reprepare_packed_git();
        }
+       return NULL;
 }
 
-static const char *unpack_with_sideband(void)
+static const char *unpack_with_sideband(struct shallow_info *si)
 {
        struct async muxer;
        const char *ret;
 
        if (!use_sideband)
-               return unpack(0);
+               return unpack(0, si);
 
        memset(&muxer, 0, sizeof(muxer));
        muxer.proc = copy_to_sideband;
@@ -911,12 +1318,97 @@ static const char *unpack_with_sideband(void)
        if (start_async(&muxer))
                return NULL;
 
-       ret = unpack(muxer.in);
+       ret = unpack(muxer.in, si);
 
        finish_async(&muxer);
        return ret;
 }
 
+static void prepare_shallow_update(struct command *commands,
+                                  struct shallow_info *si)
+{
+       int i, j, k, bitmap_size = (si->ref->nr + 31) / 32;
+
+       si->used_shallow = xmalloc(sizeof(*si->used_shallow) *
+                                  si->shallow->nr);
+       assign_shallow_commits_to_refs(si, si->used_shallow, NULL);
+
+       si->need_reachability_test =
+               xcalloc(si->shallow->nr, sizeof(*si->need_reachability_test));
+       si->reachable =
+               xcalloc(si->shallow->nr, sizeof(*si->reachable));
+       si->shallow_ref = xcalloc(si->ref->nr, sizeof(*si->shallow_ref));
+
+       for (i = 0; i < si->nr_ours; i++)
+               si->need_reachability_test[si->ours[i]] = 1;
+
+       for (i = 0; i < si->shallow->nr; i++) {
+               if (!si->used_shallow[i])
+                       continue;
+               for (j = 0; j < bitmap_size; j++) {
+                       if (!si->used_shallow[i][j])
+                               continue;
+                       si->need_reachability_test[i]++;
+                       for (k = 0; k < 32; k++)
+                               if (si->used_shallow[i][j] & (1 << k))
+                                       si->shallow_ref[j * 32 + k]++;
+               }
+
+               /*
+                * true for those associated with some refs and belong
+                * in "ours" list aka "step 7 not done yet"
+                */
+               si->need_reachability_test[i] =
+                       si->need_reachability_test[i] > 1;
+       }
+
+       /*
+        * keep hooks happy by forcing a temporary shallow file via
+        * env variable because we can't add --shallow-file to every
+        * command. check_everything_connected() will be done with
+        * true .git/shallow though.
+        */
+       setenv(GIT_SHALLOW_FILE_ENVIRONMENT, alt_shallow_file, 1);
+}
+
+static void update_shallow_info(struct command *commands,
+                               struct shallow_info *si,
+                               struct sha1_array *ref)
+{
+       struct command *cmd;
+       int *ref_status;
+       remove_nonexistent_theirs_shallow(si);
+       if (!si->nr_ours && !si->nr_theirs) {
+               shallow_update = 0;
+               return;
+       }
+
+       for (cmd = commands; cmd; cmd = cmd->next) {
+               if (is_null_sha1(cmd->new_sha1))
+                       continue;
+               sha1_array_append(ref, cmd->new_sha1);
+               cmd->index = ref->nr - 1;
+       }
+       si->ref = ref;
+
+       if (shallow_update) {
+               prepare_shallow_update(commands, si);
+               return;
+       }
+
+       ref_status = xmalloc(sizeof(*ref_status) * ref->nr);
+       assign_shallow_commits_to_refs(si, NULL, ref_status);
+       for (cmd = commands; cmd; cmd = cmd->next) {
+               if (is_null_sha1(cmd->new_sha1))
+                       continue;
+               if (ref_status[cmd->index]) {
+                       cmd->error_string = "shallow update not allowed";
+                       cmd->skip_update = 1;
+               }
+       }
+       free(ref_status);
+}
+
 static void report(struct command *commands, const char *unpack_status)
 {
        struct command *cmd;
@@ -954,10 +1446,11 @@ static int delete_only(struct command *commands)
 int cmd_receive_pack(int argc, const char **argv, const char *prefix)
 {
        int advertise_refs = 0;
-       int stateless_rpc = 0;
        int i;
-       char *dir = NULL;
        struct command *commands;
+       struct sha1_array shallow = SHA1_ARRAY_INIT;
+       struct sha1_array ref = SHA1_ARRAY_INIT;
+       struct shallow_info si;
 
        packet_trace_identity("receive-pack");
 
@@ -986,22 +1479,21 @@ int cmd_receive_pack(int argc, const char **argv, const char *prefix)
 
                        usage(receive_pack_usage);
                }
-               if (dir)
+               if (service_dir)
                        usage(receive_pack_usage);
-               dir = xstrdup(arg);
+               service_dir = arg;
        }
-       if (!dir)
+       if (!service_dir)
                usage(receive_pack_usage);
 
        setup_path();
 
-       if (!enter_repo(dir, 0))
-               die("'%s' does not appear to be a git repository", dir);
-
-       if (is_repository_shallow())
-               die("attempt to push into a shallow repository");
+       if (!enter_repo(service_dir, 0))
+               die("'%s' does not appear to be a git repository", service_dir);
 
        git_config(receive_pack_config, NULL);
+       if (cert_nonce_seed)
+               push_cert_nonce = prepare_push_cert_nonce(service_dir, time(NULL));
 
        if (0 <= transfer_unpack_limit)
                unpack_limit = transfer_unpack_limit;
@@ -1014,12 +1506,17 @@ int cmd_receive_pack(int argc, const char **argv, const char *prefix)
        if (advertise_refs)
                return 0;
 
-       if ((commands = read_head_info()) != NULL) {
+       if ((commands = read_head_info(&shallow)) != NULL) {
                const char *unpack_status = NULL;
 
-               if (!delete_only(commands))
-                       unpack_status = unpack_with_sideband();
-               execute_commands(commands, unpack_status);
+               prepare_shallow_info(&si, &shallow);
+               if (!si.nr_ours && !si.nr_theirs)
+                       shallow_update = 0;
+               if (!delete_only(commands)) {
+                       unpack_status = unpack_with_sideband(&si);
+                       update_shallow_info(commands, &si, &ref);
+               }
+               execute_commands(commands, unpack_status, &si);
                if (pack_lockfile)
                        unlink_or_warn(pack_lockfile);
                if (report_status)
@@ -1035,8 +1532,12 @@ int cmd_receive_pack(int argc, const char **argv, const char *prefix)
                }
                if (auto_update_server_info)
                        update_server_info(0);
+               clear_shallow_info(&si);
        }
        if (use_sideband)
                packet_flush(1);
+       sha1_array_clear(&shallow);
+       sha1_array_clear(&ref);
+       free((void *)push_cert_nonce);
        return 0;
 }