Fix random segfaults in pack-objects.
[gitweb.git] / receive-pack.c
index 201531626c2a60dffd1720ab4d00d7023bcbc78e..59b682c03af53fbfe600d063fa832f874440493c 100644 (file)
@@ -1,19 +1,41 @@
 #include "cache.h"
+#include "pack.h"
 #include "refs.h"
 #include "pkt-line.h"
 #include "run-command.h"
-#include <sys/wait.h>
+#include "exec_cmd.h"
+#include "commit.h"
+#include "object.h"
 
 static const char receive_pack_usage[] = "git-receive-pack <git-dir>";
 
-static const char *unpacker[] = { "unpack-objects", NULL };
-
+static int deny_non_fast_forwards = 0;
+static int unpack_limit = 100;
 static int report_status;
 
-static char capabilities[] = "report-status";
+static char capabilities[] = " report-status delete-refs ";
 static int capabilities_sent;
 
-static int show_ref(const char *path, const unsigned char *sha1)
+static int receive_pack_config(const char *var, const char *value)
+{
+       git_default_config(var, value);
+
+       if (strcmp(var, "receive.denynonfastforwards") == 0)
+       {
+               deny_non_fast_forwards = git_config_bool(var, value);
+               return 0;
+       }
+
+       if (strcmp(var, "receive.unpacklimit") == 0)
+       {
+               unpack_limit = git_config_int(var, value);
+               return 0;
+       }
+
+       return 0;
+}
+
+static int show_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 {
        if (capabilities_sent)
                packet_write(1, "%s %s\n", sha1_to_hex(sha1), path);
@@ -26,9 +48,9 @@ static int show_ref(const char *path, const unsigned char *sha1)
 
 static void write_head_info(void)
 {
-       for_each_ref(show_ref);
+       for_each_ref(show_ref, NULL);
        if (!capabilities_sent)
-               show_ref("capabilities^{}", null_sha1);
+               show_ref("capabilities^{}", null_sha1, 0, NULL);
 
 }
 
@@ -42,34 +64,6 @@ struct command {
 
 static struct command *commands;
 
-static int is_all_zeroes(const char *hex)
-{
-       int i;
-       for (i = 0; i < 40; i++)
-               if (*hex++ != '0')
-                       return 0;
-       return 1;
-}
-
-static int verify_old_ref(const char *name, char *hex_contents)
-{
-       int fd, ret;
-       char buffer[60];
-
-       if (is_all_zeroes(hex_contents))
-               return 0;
-       fd = open(name, O_RDONLY);
-       if (fd < 0)
-               return -1;
-       ret = read(fd, buffer, 40);
-       close(fd);
-       if (ret != 40)
-               return -1;
-       if (memcmp(buffer, hex_contents, 40))
-               return -1;
-       return 0;
-}
-
 static char update_hook[] = "hooks/update";
 
 static int run_update_hook(const char *refname,
@@ -106,8 +100,8 @@ static int update(struct command *cmd)
        const char *name = cmd->ref_name;
        unsigned char *old_sha1 = cmd->old_sha1;
        unsigned char *new_sha1 = cmd->new_sha1;
-       char new_hex[60], *old_hex, *lock_name;
-       int newfd, namelen, written;
+       char new_hex[41], old_hex[41];
+       struct ref_lock *lock;
 
        cmd->error_string = NULL;
        if (!strncmp(name, "refs/", 5) && check_ref_format(name + 5)) {
@@ -116,59 +110,53 @@ static int update(struct command *cmd)
                             name);
        }
 
-       namelen = strlen(name);
-       lock_name = xmalloc(namelen + 10);
-       memcpy(lock_name, name, namelen);
-       memcpy(lock_name + namelen, ".lock", 6);
-
        strcpy(new_hex, sha1_to_hex(new_sha1));
-       old_hex = sha1_to_hex(old_sha1);
-       if (!has_sha1_file(new_sha1)) {
+       strcpy(old_hex, sha1_to_hex(old_sha1));
+
+       if (!is_null_sha1(new_sha1) && !has_sha1_file(new_sha1)) {
                cmd->error_string = "bad pack";
                return error("unpack should have generated %s, "
                             "but I can't find it!", new_hex);
        }
-       safe_create_leading_directories(lock_name);
-
-       newfd = open(lock_name, O_CREAT | O_EXCL | O_WRONLY, 0666);
-       if (newfd < 0) {
-               cmd->error_string = "can't lock";
-               return error("unable to create %s (%s)",
-                            lock_name, strerror(errno));
-       }
-
-       /* Write the ref with an ending '\n' */
-       new_hex[40] = '\n';
-       new_hex[41] = 0;
-       written = write(newfd, new_hex, 41);
-       /* Remove the '\n' again */
-       new_hex[40] = 0;
-
-       close(newfd);
-       if (written != 41) {
-               unlink(lock_name);
-               cmd->error_string = "can't write";
-               return error("unable to write %s", lock_name);
-       }
-       if (verify_old_ref(name, old_hex) < 0) {
-               unlink(lock_name);
-               cmd->error_string = "raced";
-               return error("%s changed during push", name);
+       if (deny_non_fast_forwards && !is_null_sha1(new_sha1) &&
+           !is_null_sha1(old_sha1) &&
+           !strncmp(name, "refs/heads/", 11)) {
+               struct commit *old_commit, *new_commit;
+               struct commit_list *bases, *ent;
+
+               old_commit = (struct commit *)parse_object(old_sha1);
+               new_commit = (struct commit *)parse_object(new_sha1);
+               bases = get_merge_bases(old_commit, new_commit, 1);
+               for (ent = bases; ent; ent = ent->next)
+                       if (!hashcmp(old_sha1, ent->item->object.sha1))
+                               break;
+               free_commit_list(bases);
+               if (!ent)
+                       return error("denying non-fast forward;"
+                                    " you should pull first");
        }
        if (run_update_hook(name, old_hex, new_hex)) {
-               unlink(lock_name);
                cmd->error_string = "hook declined";
                return error("hook declined to update %s", name);
        }
-       else if (rename(lock_name, name) < 0) {
-               unlink(lock_name);
-               cmd->error_string = "can't rename";
-               return error("unable to replace %s", name);
+
+       if (is_null_sha1(new_sha1)) {
+               if (delete_ref(name, old_sha1)) {
+                       cmd->error_string = "failed to delete";
+                       return error("failed to delete %s", name);
+               }
+               fprintf(stderr, "%s: %s -> deleted\n", name, old_hex);
        }
        else {
+               lock = lock_any_ref_for_update(name, old_sha1);
+               if (!lock) {
+                       cmd->error_string = "failed to lock";
+                       return error("failed to lock %s", name);
+               }
+               write_ref_sha1(lock, new_sha1, "push");
                fprintf(stderr, "%s: %s -> %s\n", name, old_hex, new_hex);
-               return 0;
        }
+       return 0;
 }
 
 static char update_post_hook[] = "hooks/post-update";
@@ -257,29 +245,127 @@ static void read_head_info(void)
        }
 }
 
-static const char *unpack(int *error_code)
+static const char *parse_pack_header(struct pack_header *hdr)
 {
-       int code = run_command_v_opt(1, unpacker, RUN_GIT_CMD);
+       char *c = (char*)hdr;
+       ssize_t remaining = sizeof(struct pack_header);
+       do {
+               ssize_t r = xread(0, c, remaining);
+               if (r <= 0)
+                       return "eof before pack header was fully read";
+               remaining -= r;
+               c += r;
+       } while (remaining > 0);
+       if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
+               return "protocol error (pack signature mismatch detected)";
+       if (!pack_version_ok(hdr->hdr_version))
+               return "protocol error (pack version unsupported)";
+       return NULL;
+}
 
-       *error_code = 0;
-       switch (code) {
-       case 0:
-               return NULL;
-       case -ERR_RUN_COMMAND_FORK:
-               return "unpack fork failed";
-       case -ERR_RUN_COMMAND_EXEC:
-               return "unpack execute failed";
-       case -ERR_RUN_COMMAND_WAITPID:
-               return "waitpid failed";
-       case -ERR_RUN_COMMAND_WAITPID_WRONG_PID:
-               return "waitpid is confused";
-       case -ERR_RUN_COMMAND_WAITPID_SIGNAL:
-               return "unpacker died of signal";
-       case -ERR_RUN_COMMAND_WAITPID_NOEXIT:
-               return "unpacker died strangely";
-       default:
-               *error_code = -code;
-               return "unpacker exited with error code";
+static const char *pack_lockfile;
+
+static const char *unpack(void)
+{
+       struct pack_header hdr;
+       const char *hdr_err;
+       char hdr_arg[38];
+
+       hdr_err = parse_pack_header(&hdr);
+       if (hdr_err)
+               return hdr_err;
+       snprintf(hdr_arg, sizeof(hdr_arg), "--pack_header=%u,%u",
+                       ntohl(hdr.hdr_version), ntohl(hdr.hdr_entries));
+
+       if (ntohl(hdr.hdr_entries) < unpack_limit) {
+               int code;
+               const char *unpacker[3];
+               unpacker[0] = "unpack-objects";
+               unpacker[1] = hdr_arg;
+               unpacker[2] = NULL;
+               code = run_command_v_opt(1, unpacker, RUN_GIT_CMD);
+               switch (code) {
+               case 0:
+                       return NULL;
+               case -ERR_RUN_COMMAND_FORK:
+                       return "unpack fork failed";
+               case -ERR_RUN_COMMAND_EXEC:
+                       return "unpack execute failed";
+               case -ERR_RUN_COMMAND_WAITPID:
+                       return "waitpid failed";
+               case -ERR_RUN_COMMAND_WAITPID_WRONG_PID:
+                       return "waitpid is confused";
+               case -ERR_RUN_COMMAND_WAITPID_SIGNAL:
+                       return "unpacker died of signal";
+               case -ERR_RUN_COMMAND_WAITPID_NOEXIT:
+                       return "unpacker died strangely";
+               default:
+                       return "unpacker exited with error code";
+               }
+       } else {
+               const char *keeper[6];
+               int fd[2], s, len, status;
+               pid_t pid;
+               char keep_arg[256];
+               char packname[46];
+
+               s = sprintf(keep_arg, "--keep=receive-pack %i on ", getpid());
+               if (gethostname(keep_arg + s, sizeof(keep_arg) - s))
+                       strcpy(keep_arg + s, "localhost");
+
+               keeper[0] = "index-pack";
+               keeper[1] = "--stdin";
+               keeper[2] = "--fix-thin";
+               keeper[3] = hdr_arg;
+               keeper[4] = keep_arg;
+               keeper[5] = NULL;
+
+               if (pipe(fd) < 0)
+                       return "index-pack pipe failed";
+               pid = fork();
+               if (pid < 0)
+                       return "index-pack fork failed";
+               if (!pid) {
+                       dup2(fd[1], 1);
+                       close(fd[1]);
+                       close(fd[0]);
+                       execv_git_cmd(keeper);
+                       die("execv of index-pack failed");
+               }
+               close(fd[1]);
+
+               /*
+                * The first thing we expects from index-pack's output
+                * is "pack\t%40s\n" or "keep\t%40s\n" (46 bytes) where
+                * %40s is the newly created pack SHA1 name.  In the "keep"
+                * case, we need it to remove the corresponding .keep file
+                * later on.  If we don't get that then tough luck with it.
+                */
+               for (len = 0;
+                    len < 46 && (s = xread(fd[0], packname+len, 46-len)) > 0;
+                    len += s);
+               close(fd[0]);
+               if (len == 46 && packname[45] == '\n' &&
+                   memcmp(packname, "keep\t", 5) == 0) {
+                       char path[PATH_MAX];
+                       packname[45] = 0;
+                       snprintf(path, sizeof(path), "%s/pack/pack-%s.keep",
+                                get_object_directory(), packname + 5);
+                       pack_lockfile = xstrdup(path);
+               }
+
+               /* Then wrap our index-pack process. */
+               while (waitpid(pid, &status, 0) < 0)
+                       if (errno != EINTR)
+                               return "waitpid failed";
+               if (WIFEXITED(status)) {
+                       int code = WEXITSTATUS(status);
+                       if (code)
+                               return "index-pack exited with error code";
+                       reprepare_packed_git();
+                       return NULL;
+               }
+               return "index-pack abnormal exit";
        }
 }
 
@@ -299,6 +385,16 @@ static void report(const char *unpack_status)
        packet_flush(1);
 }
 
+static int delete_only(struct command *cmd)
+{
+       while (cmd) {
+               if (!is_null_sha1(cmd->new_sha1))
+                       return 0;
+               cmd = cmd->next;
+       }
+       return 1;
+}
+
 int main(int argc, char **argv)
 {
        int i;
@@ -319,9 +415,14 @@ int main(int argc, char **argv)
        if (!dir)
                usage(receive_pack_usage);
 
-       if(!enter_repo(dir, 0))
+       if (!enter_repo(dir, 0))
                die("'%s': unable to chdir or not a git archive", dir);
 
+       setup_ident();
+       /* don't die if gecos is empty */
+       ignore_missing_committer_name();
+       git_config(receive_pack_config);
+
        write_head_info();
 
        /* EOF */
@@ -329,10 +430,14 @@ int main(int argc, char **argv)
 
        read_head_info();
        if (commands) {
-               int code;
-               const char *unpack_status = unpack(&code);
+               const char *unpack_status = NULL;
+
+               if (!delete_only(commands))
+                       unpack_status = unpack();
                if (!unpack_status)
                        execute_commands();
+               if (pack_lockfile)
+                       unlink(pack_lockfile);
                if (report_status)
                        report(unpack_status);
        }