receive-pack.c

   1 #include "cache.h"
   2 #include "pkt-line.h"
   3 #include <sys/wait.h>
   4
   5 static const char receive_pack_usage[] = "git-receive-pack [--unpack=executable] <git-dir> [heads]";
   6
   7 static const char *unpacker = "git-unpack-objects";
   8
   9 static int path_match(const char *path, int nr, char **match)
  10 {
  11         int i;
  12         int pathlen = strlen(path);
  13
  14         for (i = 0; i < nr; i++) {
  15                 char *s = match[i];
  16                 int len = strlen(s);
  17
  18                 if (!len || len > pathlen)
  19                         continue;
  20                 if (memcmp(path + pathlen - len, s, len))
  21                         continue;
  22                 if (pathlen > len && path[pathlen - len - 1] != '/')
  23                         continue;
  24                 *s = 0;
  25                 return 1;
  26         }
  27         return 0;
  28 }
  29
  30 static void show_ref(const char *path, unsigned char *sha1)
  31 {
  32         packet_write(1, "%s %s\n", sha1_to_hex(sha1), path);
  33 }
  34
  35 static int read_ref(const char *path, unsigned char *sha1)
  36 {
  37         int ret = -1;
  38         int fd = open(path, O_RDONLY);
  39
  40         if (fd >= 0) {
  41                 char buffer[60];
  42                 if (read(fd, buffer, sizeof(buffer)) >= 40)
  43                         ret = get_sha1_hex(buffer, sha1);
  44                 close(fd);
  45         }
  46         return ret;
  47 }
  48
  49 static void write_head_info(const char *base, int nr, char **match)
  50 {
  51         DIR *dir = opendir(base);
  52
  53         if (dir) {
  54                 struct dirent *de;
  55                 int baselen = strlen(base);
  56                 char *path = xmalloc(baselen + 257);
  57                 memcpy(path, base, baselen);
  58
  59                 while ((de = readdir(dir)) != NULL) {
  60                         char sha1[20];
  61                         struct stat st;
  62                         int namelen;
  63
  64                         if (de->d_name[0] == '.')
  65                                 continue;
  66                         namelen = strlen(de->d_name);
  67                         if (namelen > 255)
  68                                 continue;
  69                         memcpy(path + baselen, de->d_name, namelen+1);
  70                         if (lstat(path, &st) < 0)
  71                                 continue;
  72                         if (S_ISDIR(st.st_mode)) {
  73                                 path[baselen + namelen] = '/';
  74                                 path[baselen + namelen + 1] = 0;
  75                                 write_head_info(path, nr, match);
  76                                 continue;
  77                         }
  78                         if (read_ref(path, sha1) < 0)
  79                                 continue;
  80                         if (!has_sha1_file(sha1))
  81                                 continue;
  82                         if (nr && !path_match(path, nr, match))
  83                                 continue;
  84                         show_ref(path, sha1);
  85                 }
  86                 free(path);
  87                 closedir(dir);
  88         }
  89 }
  90
  91 struct command {
  92         struct command *next;
  93         unsigned char old_sha1[20];
  94         unsigned char new_sha1[20];
  95         char ref_name[0];
  96 };
  97
  98 struct command *commands = NULL;
  99
 100 static int is_all_zeroes(const char *hex)
 101 {
 102         int i;
 103         for (i = 0; i < 40; i++)
 104                 if (*hex++ != '0')
 105                         return 0;
 106         return 1;
 107 }
 108
 109 static int verify_old_ref(const char *name, char *hex_contents)
 110 {
 111         int fd, ret;
 112         char buffer[60];
 113
 114         if (is_all_zeroes(hex_contents))
 115                 return 0;
 116         fd = open(name, O_RDONLY);
 117         if (fd < 0)
 118                 return -1;
 119         ret = read(fd, buffer, 40);
 120         close(fd);
 121         if (ret != 40)
 122                 return -1;
 123         if (memcmp(buffer, hex_contents, 40))
 124                 return -1;
 125         return 0;
 126 }
 127
 128 static void update(const char *name, unsigned char *old_sha1, unsigned char *new_sha1)
 129 {
 130         char new_hex[60], *old_hex, *lock_name;
 131         int newfd, namelen, written;
 132
 133         namelen = strlen(name);
 134         lock_name = xmalloc(namelen + 10);
 135         memcpy(lock_name, name, namelen);
 136         memcpy(lock_name + namelen, ".lock", 6);
 137
 138         strcpy(new_hex, sha1_to_hex(new_sha1));
 139         old_hex = sha1_to_hex(old_sha1);
 140         if (!has_sha1_file(new_sha1))
 141                 die("unpack should have generated %s, but I can't find it!", new_hex);
 142
 143         newfd = open(lock_name, O_CREAT | O_EXCL | O_WRONLY, 0644);
 144         if (newfd < 0)
 145                 die("unable to create %s (%s)", lock_name, strerror(errno));
 146
 147         /* Write the ref with an ending '\n' */
 148         new_hex[40] = '\n';
 149         new_hex[41] = 0;
 150         written = write(newfd, new_hex, 41);
 151         /* Remove the '\n' again */
 152         new_hex[40] = 0;
 153
 154         close(newfd);
 155         if (written != 41) {
 156                 unlink(lock_name);
 157                 die("unable to write %s", lock_name);
 158         }
 159         if (verify_old_ref(name, old_hex) < 0) {
 160                 unlink(lock_name);
 161                 die("%s changed during push", name);
 162         }
 163         if (rename(lock_name, name) < 0) {
 164                 unlink(lock_name);
 165                 die("unable to replace %s", name);
 166         }
 167         fprintf(stderr, "%s: %s -> %s\n", name, old_hex, new_hex);
 168 }
 169
 170
 171 /*
 172  * This gets called after(if) we've successfully
 173  * unpacked the data payload.
 174  */
 175 static void execute_commands(void)
 176 {
 177         struct command *cmd = commands;
 178
 179         while (cmd) {
 180                 update(cmd->ref_name, cmd->old_sha1, cmd->new_sha1);
 181                 cmd = cmd->next;
 182         }
 183 }
 184
 185 static void read_head_info(void)
 186 {
 187         struct command **p = &commands;
 188         for (;;) {
 189                 static char line[1000];
 190                 unsigned char old_sha1[20], new_sha1[20];
 191                 struct command *cmd;
 192                 int len;
 193
 194                 len = packet_read_line(0, line, sizeof(line));
 195                 if (!len)
 196                         break;
 197                 if (line[len-1] == '\n')
 198                         line[--len] = 0;
 199                 if (len < 83 ||
 200                     line[40] != ' ' ||
 201                     line[81] != ' ' ||
 202                     get_sha1_hex(line, old_sha1) ||
 203                     get_sha1_hex(line + 41, new_sha1))
 204                         die("protocol error: expected old/new/ref, got '%s'", line);
 205                 cmd = xmalloc(sizeof(struct command) + len - 80);
 206                 memcpy(cmd->old_sha1, old_sha1, 20);
 207                 memcpy(cmd->new_sha1, new_sha1, 20);
 208                 memcpy(cmd->ref_name, line + 82, len - 81);
 209                 cmd->next = NULL;
 210                 *p = cmd;
 211                 p = &cmd->next;
 212         }
 213 }
 214
 215 static void unpack(void)
 216 {
 217         pid_t pid = fork();
 218
 219         if (pid < 0)
 220                 die("unpack fork failed");
 221         if (!pid) {
 222                 execlp(unpacker, unpacker, NULL);
 223                 die("unpack execute failed");
 224         }
 225
 226         for (;;) {
 227                 int status, code;
 228                 int retval = waitpid(pid, &status, 0);
 229
 230                 if (retval < 0) {
 231                         if (errno == EINTR)
 232                                 continue;
 233                         die("waitpid failed (%s)", strerror(retval));
 234                 }
 235                 if (retval != pid)
 236                         die("waitpid is confused");
 237                 if (WIFSIGNALED(status))
 238                         die("%s died of signal %d", unpacker, WTERMSIG(status));
 239                 if (!WIFEXITED(status))
 240                         die("%s died out of really strange complications", unpacker);
 241                 code = WEXITSTATUS(status);
 242                 if (code)
 243                         die("%s exited with error code %d", unpacker, code);
 244                 return;
 245         }
 246 }
 247
 248 int main(int argc, char **argv)
 249 {
 250         int i, nr_heads = 0;
 251         const char *dir = NULL;
 252         char **heads = NULL;
 253
 254         argv++;
 255         for (i = 1; i < argc; i++) {
 256                 const char *arg = *argv++;
 257
 258                 if (*arg == '-') {
 259                         if (!strncmp(arg, "--unpack=", 9)) {
 260                                 unpacker = arg+9;
 261                                 continue;
 262                         }
 263                         /* Do flag handling here */
 264                         usage(receive_pack_usage);
 265                 }
 266                 dir = arg;
 267                 heads = argv;
 268                 nr_heads = argc - i - 1;
 269                 break;
 270         }
 271         if (!dir)
 272                 usage(receive_pack_usage);
 273
 274         /* chdir to the directory. If that fails, try appending ".git" */
 275         if (chdir(dir) < 0) {
 276                 static char path[PATH_MAX];
 277                 snprintf(path, sizeof(path), "%s.git", dir);
 278                 if (chdir(path) < 0)
 279                         die("unable to cd to %s", dir);
 280         }
 281
 282         /* If we have a ".git" directory, chdir to it */
 283         chdir(".git");
 284         setenv("GIT_DIR", ".", 1);
 285
 286         if (access("objects", X_OK) < 0 || access("refs/heads", X_OK) < 0)
 287                 die("%s doesn't appear to be a git directory", dir);
 288         write_head_info("refs/", nr_heads, heads);
 289
 290         /* EOF */
 291         packet_flush(1);
 292
 293         read_head_info();
 294         if (commands) {
 295                 unpack();
 296                 execute_commands();
 297         }
 298         return 0;
 299 }