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