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