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