receive-pack.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "pkt-line.h"
   4 #include "run-command.h"
   5 #include <sys/wait.h>
   6
   7 static const char receive_pack_usage[] = "git-receive-pack <git-dir>";
   8
   9 static const char unpacker[] = "git-unpack-objects";
  10
  11 static int report_status = 0;
  12
  13 static char capabilities[] = "report-status";
  14 static int capabilities_sent = 0;
  15
  16 static int show_ref(const char *path, const unsigned char *sha1)
  17 {
  18         if (capabilities_sent)
  19                 packet_write(1, "%s %s\n", sha1_to_hex(sha1), path);
  20         else
  21                 packet_write(1, "%s %s%c%s\n",
  22                              sha1_to_hex(sha1), path, 0, capabilities);
  23         capabilities_sent = 1;
  24         return 0;
  25 }
  26
  27 static void write_head_info(void)
  28 {
  29         for_each_ref(show_ref);
  30         if (!capabilities_sent)
  31                 show_ref("capabilities^{}", null_sha1);
  32
  33 }
  34
  35 struct command {
  36         struct command *next;
  37         const char *error_string;
  38         unsigned char old_sha1[20];
  39         unsigned char new_sha1[20];
  40         char ref_name[FLEX_ARRAY]; /* more */
  41 };
  42
  43 static struct command *commands = NULL;
  44
  45 static int is_all_zeroes(const char *hex)
  46 {
  47         int i;
  48         for (i = 0; i < 40; i++)
  49                 if (*hex++ != '0')
  50                         return 0;
  51         return 1;
  52 }
  53
  54 static int verify_old_ref(const char *name, char *hex_contents)
  55 {
  56         int fd, ret;
  57         char buffer[60];
  58
  59         if (is_all_zeroes(hex_contents))
  60                 return 0;
  61         fd = open(name, O_RDONLY);
  62         if (fd < 0)
  63                 return -1;
  64         ret = read(fd, buffer, 40);
  65         close(fd);
  66         if (ret != 40)
  67                 return -1;
  68         if (memcmp(buffer, hex_contents, 40))
  69                 return -1;
  70         return 0;
  71 }
  72
  73 static char update_hook[] = "hooks/update";
  74
  75 static int run_update_hook(const char *refname,
  76                            char *old_hex, char *new_hex)
  77 {
  78         int code;
  79
  80         if (access(update_hook, X_OK) < 0)
  81                 return 0;
  82         code = run_command(update_hook, refname, old_hex, new_hex, NULL);
  83         switch (code) {
  84         case 0:
  85                 return 0;
  86         case -ERR_RUN_COMMAND_FORK:
  87                 return error("hook fork failed");
  88         case -ERR_RUN_COMMAND_EXEC:
  89                 return error("hook execute failed");
  90         case -ERR_RUN_COMMAND_WAITPID:
  91                 return error("waitpid failed");
  92         case -ERR_RUN_COMMAND_WAITPID_WRONG_PID:
  93                 return error("waitpid is confused");
  94         case -ERR_RUN_COMMAND_WAITPID_SIGNAL:
  95                 return error("%s died of signal\n", update_hook);
  96         case -ERR_RUN_COMMAND_WAITPID_NOEXIT:
  97                 return error("%s died strangely", update_hook);
  98         default:
  99                 error("%s exited with error code %d", update_hook, -code);
 100                 return -code;
 101         }
 102 }
 103
 104 static int update(struct command *cmd)
 105 {
 106         const char *name = cmd->ref_name;
 107         unsigned char *old_sha1 = cmd->old_sha1;
 108         unsigned char *new_sha1 = cmd->new_sha1;
 109         char new_hex[60], *old_hex, *lock_name;
 110         int newfd, namelen, written;
 111
 112         cmd->error_string = NULL;
 113         if (!strncmp(name, "refs/", 5) && check_ref_format(name + 5)) {
 114                 cmd->error_string = "funny refname";
 115                 return error("refusing to create funny ref '%s' locally",
 116                              name);
 117         }
 118
 119         namelen = strlen(name);
 120         lock_name = xmalloc(namelen + 10);
 121         memcpy(lock_name, name, namelen);
 122         memcpy(lock_name + namelen, ".lock", 6);
 123
 124         strcpy(new_hex, sha1_to_hex(new_sha1));
 125         old_hex = sha1_to_hex(old_sha1);
 126         if (!has_sha1_file(new_sha1)) {
 127                 cmd->error_string = "bad pack";
 128                 return error("unpack should have generated %s, "
 129                              "but I can't find it!", new_hex);
 130         }
 131         safe_create_leading_directories(lock_name);
 132
 133         newfd = open(lock_name, O_CREAT | O_EXCL | O_WRONLY, 0666);
 134         if (newfd < 0) {
 135                 cmd->error_string = "can't lock";
 136                 return error("unable to create %s (%s)",
 137                              lock_name, strerror(errno));
 138         }
 139
 140         /* Write the ref with an ending '\n' */
 141         new_hex[40] = '\n';
 142         new_hex[41] = 0;
 143         written = write(newfd, new_hex, 41);
 144         /* Remove the '\n' again */
 145         new_hex[40] = 0;
 146
 147         close(newfd);
 148         if (written != 41) {
 149                 unlink(lock_name);
 150                 cmd->error_string = "can't write";
 151                 return error("unable to write %s", lock_name);
 152         }
 153         if (verify_old_ref(name, old_hex) < 0) {
 154                 unlink(lock_name);
 155                 cmd->error_string = "raced";
 156                 return error("%s changed during push", name);
 157         }
 158         if (run_update_hook(name, old_hex, new_hex)) {
 159                 unlink(lock_name);
 160                 cmd->error_string = "hook declined";
 161                 return error("hook declined to update %s\n", name);
 162         }
 163         else if (rename(lock_name, name) < 0) {
 164                 unlink(lock_name);
 165                 cmd->error_string = "can't rename";
 166                 return error("unable to replace %s", name);
 167         }
 168         else {
 169                 fprintf(stderr, "%s: %s -> %s\n", name, old_hex, new_hex);
 170                 return 0;
 171         }
 172 }
 173
 174 static char update_post_hook[] = "hooks/post-update";
 175
 176 static void run_update_post_hook(struct command *cmd)
 177 {
 178         struct command *cmd_p;
 179         int argc;
 180         char **argv;
 181
 182         if (access(update_post_hook, X_OK) < 0)
 183                 return;
 184         for (argc = 1, cmd_p = cmd; cmd_p; cmd_p = cmd_p->next) {
 185                 if (cmd_p->error_string)
 186                         continue;
 187                 argc++;
 188         }
 189         argv = xmalloc(sizeof(*argv) * (1 + argc));
 190         argv[0] = update_post_hook;
 191
 192         for (argc = 1, cmd_p = cmd; cmd_p; cmd_p = cmd_p->next) {
 193                 if (cmd_p->error_string)
 194                         continue;
 195                 argv[argc] = xmalloc(strlen(cmd_p->ref_name) + 1);
 196                 strcpy(argv[argc], cmd_p->ref_name);
 197                 argc++;
 198         }
 199         argv[argc] = NULL;
 200         run_command_v_opt(argc, argv, RUN_COMMAND_NO_STDIO);
 201 }
 202
 203 /*
 204  * This gets called after(if) we've successfully
 205  * unpacked the data payload.
 206  */
 207 static void execute_commands(void)
 208 {
 209         struct command *cmd = commands;
 210
 211         while (cmd) {
 212                 update(cmd);
 213                 cmd = cmd->next;
 214         }
 215         run_update_post_hook(commands);
 216 }
 217
 218 static void read_head_info(void)
 219 {
 220         struct command **p = &commands;
 221         for (;;) {
 222                 static char line[1000];
 223                 unsigned char old_sha1[20], new_sha1[20];
 224                 struct command *cmd;
 225                 char *refname;
 226                 int len, reflen;
 227
 228                 len = packet_read_line(0, line, sizeof(line));
 229                 if (!len)
 230                         break;
 231                 if (line[len-1] == '\n')
 232                         line[--len] = 0;
 233                 if (len < 83 ||
 234                     line[40] != ' ' ||
 235                     line[81] != ' ' ||
 236                     get_sha1_hex(line, old_sha1) ||
 237                     get_sha1_hex(line + 41, new_sha1))
 238                         die("protocol error: expected old/new/ref, got '%s'",
 239                             line);
 240
 241                 refname = line + 82;
 242                 reflen = strlen(refname);
 243                 if (reflen + 82 < len) {
 244                         if (strstr(refname + reflen + 1, "report-status"))
 245                                 report_status = 1;
 246                 }
 247                 cmd = xmalloc(sizeof(struct command) + len - 80);
 248                 memcpy(cmd->old_sha1, old_sha1, 20);
 249                 memcpy(cmd->new_sha1, new_sha1, 20);
 250                 memcpy(cmd->ref_name, line + 82, len - 81);
 251                 cmd->error_string = "n/a (unpacker error)";
 252                 cmd->next = NULL;
 253                 *p = cmd;
 254                 p = &cmd->next;
 255         }
 256 }
 257
 258 static const char *unpack(int *error_code)
 259 {
 260         int code = run_command(unpacker, NULL);
 261
 262         *error_code = 0;
 263         switch (code) {
 264         case 0:
 265                 return NULL;
 266         case -ERR_RUN_COMMAND_FORK:
 267                 return "unpack fork failed";
 268         case -ERR_RUN_COMMAND_EXEC:
 269                 return "unpack execute failed";
 270         case -ERR_RUN_COMMAND_WAITPID:
 271                 return "waitpid failed";
 272         case -ERR_RUN_COMMAND_WAITPID_WRONG_PID:
 273                 return "waitpid is confused";
 274         case -ERR_RUN_COMMAND_WAITPID_SIGNAL:
 275                 return "unpacker died of signal";
 276         case -ERR_RUN_COMMAND_WAITPID_NOEXIT:
 277                 return "unpacker died strangely";
 278         default:
 279                 *error_code = -code;
 280                 return "unpacker exited with error code";
 281         }
 282 }
 283
 284 static void report(const char *unpack_status)
 285 {
 286         struct command *cmd;
 287         packet_write(1, "unpack %s\n",
 288                      unpack_status ? unpack_status : "ok");
 289         for (cmd = commands; cmd; cmd = cmd->next) {
 290                 if (!cmd->error_string)
 291                         packet_write(1, "ok %s\n",
 292                                      cmd->ref_name);
 293                 else
 294                         packet_write(1, "ng %s %s\n",
 295                                      cmd->ref_name, cmd->error_string);
 296         }
 297         packet_flush(1);
 298 }
 299
 300 int main(int argc, char **argv)
 301 {
 302         int i;
 303         char *dir = NULL;
 304
 305         argv++;
 306         for (i = 1; i < argc; i++) {
 307                 char *arg = *argv++;
 308
 309                 if (*arg == '-') {
 310                         /* Do flag handling here */
 311                         usage(receive_pack_usage);
 312                 }
 313                 if (dir)
 314                         usage(receive_pack_usage);
 315                 dir = arg;
 316         }
 317         if (!dir)
 318                 usage(receive_pack_usage);
 319
 320         if(!enter_repo(dir, 0))
 321                 die("'%s': unable to chdir or not a git archive", dir);
 322
 323         write_head_info();
 324
 325         /* EOF */
 326         packet_flush(1);
 327
 328         read_head_info();
 329         if (commands) {
 330                 int code;
 331                 const char *unpack_status = unpack(&code);
 332                 if (!unpack_status)
 333                         execute_commands();
 334                 if (report_status)
 335                         report(unpack_status);
 336         }
 337         return 0;
 338 }