git-describe: documentation.
[gitweb.git] / receive-pack.c
index 601388314418349bf61e7de14d188b8fbb802aac..92878ecac3bdb12efe0d34257852b432558e21f6 100644 (file)
 #include "cache.h"
+#include "refs.h"
+#include "pkt-line.h"
+#include "run-command.h"
 #include <sys/wait.h>
 
-static const char receive_pack_usage[] = "git-receive-pack [--unpack=executable] <git-dir> [heads]";
+static const char receive_pack_usage[] = "git-receive-pack <git-dir>";
 
-static const char *unpacker = "git-unpack-objects";
+static const char unpacker[] = "git-unpack-objects";
 
-static int path_match(const char *path, int nr, char **match)
+static int show_ref(const char *path, const unsigned char *sha1)
 {
-       int i;
-       int pathlen = strlen(path);
-
-       for (i = 0; i < nr; i++) {
-               char *s = match[i];
-               int len = strlen(s);
-
-               if (!len || len > pathlen)
-                       continue;
-               if (memcmp(path + pathlen - len, s, len))
-                       continue;
-               if (pathlen > len && path[pathlen - len - 1] != '/')
-                       continue;
-               *s = 0;
-               return 1;
-       }
+       packet_write(1, "%s %s\n", sha1_to_hex(sha1), path);
        return 0;
 }
 
-static void safe_write(int fd, const void *buf, unsigned n)
+static void write_head_info(void)
 {
-       while (n) {
-               int ret = write(fd, buf, n);
-               if (ret > 0) {
-                       buf += ret;
-                       n -= ret;
-                       continue;
-               }
-               if (!ret)
-                       die("write error (disk full?)");
-               if (errno == EAGAIN || errno == EINTR)
-                       continue;
-               die("write error (%s)", strerror(errno));
-       }
+       for_each_ref(show_ref);
 }
 
-/*
- * If we buffered things up above (we don't, but we should),
- * we'd flush it here
- */
-static void flush_safe(int fd)
-{
-}
+struct command {
+       struct command *next;
+       unsigned char updated;
+       unsigned char old_sha1[20];
+       unsigned char new_sha1[20];
+       char ref_name[0];
+};
 
-/*
- * Write a packetized stream, where each line is preceded by
- * its length (including the header) as a 4-byte hex number.
- * A length of 'zero' means end of stream (and a length of 1-3
- * would be an error). 
- */
-#define hex(a) (hexchar[(a) & 15])
-static void packet_write(const char *fmt, ...)
-{
-       static char buffer[1000];
-       static char hexchar[] = "0123456789abcdef";
-       va_list args;
-       unsigned n;
-
-       va_start(args, fmt);
-       n = vsnprintf(buffer + 4, sizeof(buffer) - 4, fmt, args);
-       va_end(args);
-       if (n >= sizeof(buffer)-4)
-               die("protocol error: impossibly long line");
-       n += 4;
-       buffer[0] = hex(n >> 12);
-       buffer[1] = hex(n >> 8);
-       buffer[2] = hex(n >> 4);
-       buffer[3] = hex(n);
-       safe_write(1, buffer, n);
-}
+static struct command *commands = NULL;
 
-static void show_ref(const char *path, unsigned char *sha1)
+static int is_all_zeroes(const char *hex)
 {
-       packet_write("%s %s\n", sha1_to_hex(sha1), path);
+       int i;
+       for (i = 0; i < 40; i++)
+               if (*hex++ != '0')
+                       return 0;
+       return 1;
 }
 
-static int read_ref(const char *path, unsigned char *sha1)
+static int verify_old_ref(const char *name, char *hex_contents)
 {
-       int ret = -1;
-       int fd = open(path, O_RDONLY);
-
-       if (fd >= 0) {
-               char buffer[60];
-               if (read(fd, buffer, sizeof(buffer)) >= 40)
-                       ret = get_sha1_hex(buffer, sha1);
-               close(fd);
-       }
-       return ret;
+       int fd, ret;
+       char buffer[60];
+
+       if (is_all_zeroes(hex_contents))
+               return 0;
+       fd = open(name, O_RDONLY);
+       if (fd < 0)
+               return -1;
+       ret = read(fd, buffer, 40);
+       close(fd);
+       if (ret != 40)
+               return -1;
+       if (memcmp(buffer, hex_contents, 40))
+               return -1;
+       return 0;
 }
 
-static void write_head_info(const char *base, int nr, char **match)
+static char update_hook[] = "hooks/update";
+
+static int run_update_hook(const char *refname,
+                          char *old_hex, char *new_hex)
 {
-       DIR *dir = opendir(base);
-
-       if (dir) {
-               struct dirent *de;
-               int baselen = strlen(base);
-               char *path = xmalloc(baselen + 257);
-               memcpy(path, base, baselen);
-
-               while ((de = readdir(dir)) != NULL) {
-                       char sha1[20];
-                       struct stat st;
-                       int namelen;
-
-                       if (de->d_name[0] == '.')
-                               continue;
-                       namelen = strlen(de->d_name);
-                       if (namelen > 255)
-                               continue;
-                       memcpy(path + baselen, de->d_name, namelen+1);
-                       if (lstat(path, &st) < 0)
-                               continue;
-                       if (S_ISDIR(st.st_mode)) {
-                               path[baselen + namelen] = '/';
-                               path[baselen + namelen + 1] = 0;
-                               write_head_info(path, nr, match);
-                               continue;
-                       }
-                       if (read_ref(path, sha1) < 0)
-                               continue;
-                       if (nr && !path_match(path, nr, match))
-                               continue;
-                       show_ref(path, sha1);
-               }
-               free(path);
-               closedir(dir);
+       int code;
+
+       if (access(update_hook, X_OK) < 0)
+               return 0;
+       code = run_command(update_hook, refname, old_hex, new_hex, NULL);
+       switch (code) {
+       case 0:
+               return 0;
+       case -ERR_RUN_COMMAND_FORK:
+               die("hook fork failed");
+       case -ERR_RUN_COMMAND_EXEC:
+               die("hook execute failed");
+       case -ERR_RUN_COMMAND_WAITPID:
+               die("waitpid failed");
+       case -ERR_RUN_COMMAND_WAITPID_WRONG_PID:
+               die("waitpid is confused");
+       case -ERR_RUN_COMMAND_WAITPID_SIGNAL:
+               fprintf(stderr, "%s died of signal\n", update_hook);
+               return -1;
+       case -ERR_RUN_COMMAND_WAITPID_NOEXIT:
+               die("%s died strangely", update_hook);
+       default:
+               error("%s exited with error code %d", update_hook, -code);
+               return -code;
        }
 }
 
-/*
- * This is all pretty stupid, but we use this packetized line
- * format to make a streaming format possible without ever
- * over-running the read buffers. That way we'll never read
- * into what might be the pack data (which should go to another
- * process entirely).
- *
- * The writing side could use stdio, but since the reading
- * side can't, we stay with pure read/write interfaces.
- */
-static void safe_read(int fd, void *buffer, unsigned size)
+static int update(const char *name,
+                 unsigned char *old_sha1, unsigned char *new_sha1)
 {
-       int n = 0;
-
-       while (n < size) {
-               int ret = read(0, buffer + n, size - n);
-               if (ret < 0) {
-                       if (errno == EINTR || errno == EAGAIN)
-                               continue;
-                       die("read error (%s)", strerror(errno));
-               }
-               if (!ret)
-                       die("unexpected EOF");
-               n += ret;
+       char new_hex[60], *old_hex, *lock_name;
+       int newfd, namelen, written;
+
+       if (!strncmp(name, "refs/", 5) && check_ref_format(name + 5))
+               return error("refusing to create funny ref '%s' locally",
+                            name);
+
+       namelen = strlen(name);
+       lock_name = xmalloc(namelen + 10);
+       memcpy(lock_name, name, namelen);
+       memcpy(lock_name + namelen, ".lock", 6);
+
+       strcpy(new_hex, sha1_to_hex(new_sha1));
+       old_hex = sha1_to_hex(old_sha1);
+       if (!has_sha1_file(new_sha1))
+               return error("unpack should have generated %s, "
+                            "but I can't find it!", new_hex);
+
+       safe_create_leading_directories(lock_name);
+
+       newfd = open(lock_name, O_CREAT | O_EXCL | O_WRONLY, 0666);
+       if (newfd < 0)
+               return error("unable to create %s (%s)",
+                            lock_name, strerror(errno));
+
+       /* Write the ref with an ending '\n' */
+       new_hex[40] = '\n';
+       new_hex[41] = 0;
+       written = write(newfd, new_hex, 41);
+       /* Remove the '\n' again */
+       new_hex[40] = 0;
+
+       close(newfd);
+       if (written != 41) {
+               unlink(lock_name);
+               return error("unable to write %s", lock_name);
+       }
+       if (verify_old_ref(name, old_hex) < 0) {
+               unlink(lock_name);
+               return error("%s changed during push", name);
+       }
+       if (run_update_hook(name, old_hex, new_hex)) {
+               unlink(lock_name);
+               return error("hook declined to update %s\n", name);
+       }
+       else if (rename(lock_name, name) < 0) {
+               unlink(lock_name);
+               return error("unable to replace %s", name);
+       }
+       else {
+               fprintf(stderr, "%s: %s -> %s\n", name, old_hex, new_hex);
+               return 0;
        }
 }
 
-static int safe_read_line(char *buffer, unsigned size)
-{
-       int n, len;
+static char update_post_hook[] = "hooks/post-update";
 
-       safe_read(0, buffer, 4);
+static void run_update_post_hook(struct command *cmd)
+{
+       struct command *cmd_p;
+       int argc;
+       char **argv;
 
-       len = 0;
-       for (n = 0; n < 4; n++) {
-               unsigned char c = buffer[n];
-               len <<= 4;
-               if (c >= '0' && c <= '9') {
-                       len += c - '0';
-                       continue;
-               }
-               if (c >= 'a' && c <= 'f') {
-                       len += c - 'a' + 10;
+       if (access(update_post_hook, X_OK) < 0)
+               return;
+       for (argc = 1, cmd_p = cmd; cmd_p; cmd_p = cmd_p->next) {
+               if (!cmd_p->updated)
                        continue;
-               }
-               if (c >= 'A' && c <= 'F') {
-                       len += c - 'A' + 10;
+               argc++;
+       }
+       argv = xmalloc(sizeof(*argv) * (1 + argc));
+       argv[0] = update_post_hook;
+
+       for (argc = 1, cmd_p = cmd; cmd_p; cmd_p = cmd_p->next) {
+               if (!cmd_p->updated)
                        continue;
-               }
-               die("protocol error: bad line length character");
+               argv[argc] = xmalloc(strlen(cmd_p->ref_name) + 1);
+               strcpy(argv[argc], cmd_p->ref_name);
+               argc++;
        }
-       if (!len)
-               return 0;
-       if (len < 4 || len >= size)
-               die("protocol error: bad line length %d", len);
-       safe_read(0, buffer + 4, len - 4);
-       buffer[len] = 0;
-       return len;
+       argv[argc] = NULL;
+       run_command_v_opt(argc, argv, RUN_COMMAND_NO_STDIO);
 }
 
-struct line {
-       struct line *next;
-       char data[0];
-};
-
-struct line *commands = NULL;
-
 /*
  * This gets called after(if) we've successfully
  * unpacked the data payload.
  */
 static void execute_commands(void)
 {
-       struct line *line = commands;
+       struct command *cmd = commands;
 
-       while (line) {
-               printf("%s", line->data);
-               line = line->next;
+       while (cmd) {
+               cmd->updated = !update(cmd->ref_name,
+                                      cmd->old_sha1, cmd->new_sha1);
+               cmd = cmd->next;
        }
+       run_update_post_hook(commands);
 }
 
 static void read_head_info(void)
 {
-       struct line **p = &commands;
+       struct command **p = &commands;
        for (;;) {
                static char line[1000];
-               int len = safe_read_line(line, sizeof(line));
-               struct line *n;
+               unsigned char old_sha1[20], new_sha1[20];
+               struct command *cmd;
+               int len;
+
+               len = packet_read_line(0, line, sizeof(line));
                if (!len)
                        break;
-               n = xmalloc(sizeof(struct line) + len);
-               n->next = NULL;
-               memcpy(n->data, line + 4, len - 3);
-               *p = n;
-               p = &n->next;
+               if (line[len-1] == '\n')
+                       line[--len] = 0;
+               if (len < 83 ||
+                   line[40] != ' ' ||
+                   line[81] != ' ' ||
+                   get_sha1_hex(line, old_sha1) ||
+                   get_sha1_hex(line + 41, new_sha1))
+                       die("protocol error: expected old/new/ref, got '%s'", line);
+               cmd = xmalloc(sizeof(struct command) + len - 80);
+               memcpy(cmd->old_sha1, old_sha1, 20);
+               memcpy(cmd->new_sha1, new_sha1, 20);
+               memcpy(cmd->ref_name, line + 82, len - 81);
+               cmd->next = NULL;
+               *p = cmd;
+               p = &cmd->next;
        }
 }
 
 static void unpack(void)
 {
-       pid_t pid = fork();
-
-       if (pid < 0)
+       int code = run_command(unpacker, NULL);
+       switch (code) {
+       case 0:
+               return;
+       case -ERR_RUN_COMMAND_FORK:
                die("unpack fork failed");
-       if (!pid) {
-               char *const envp[] = { "GIT_DIR=.", NULL };
-               execle(unpacker, unpacker, NULL, envp);
+       case -ERR_RUN_COMMAND_EXEC:
                die("unpack execute failed");
-       }
-
-       for (;;) {
-               int status, code;
-               int retval = waitpid(pid, &status, 0);
-
-               if (retval < 0) {
-                       if (errno == EINTR)
-                               continue;
-                       die("waitpid failed (%s)", strerror(retval));
-               }
-               if (retval != pid)
-                       die("waitpid is confused");
-               if (WIFSIGNALED(status))
-                       die("%s died of signal %d", unpacker, WTERMSIG(status));
-               if (!WIFEXITED(status))
-                       die("%s died out of really strange complications", unpacker);
-               code = WEXITSTATUS(status);
-               if (code)
-                       die("%s exited with error code %d", unpacker, code);
-               return;
+       case -ERR_RUN_COMMAND_WAITPID:
+               die("waitpid failed");
+       case -ERR_RUN_COMMAND_WAITPID_WRONG_PID:
+               die("waitpid is confused");
+       case -ERR_RUN_COMMAND_WAITPID_SIGNAL:
+               die("%s died of signal", unpacker);
+       case -ERR_RUN_COMMAND_WAITPID_NOEXIT:
+               die("%s died strangely", unpacker);
+       default:
+               die("%s exited with error code %d", unpacker, -code);
        }
 }
 
 int main(int argc, char **argv)
 {
-       int i, nr_heads = 0;
-       const char *dir = NULL;
-       char **heads = NULL;
+       int i;
+       char *dir = NULL;
 
        argv++;
        for (i = 1; i < argc; i++) {
-               const char *arg = *argv++;
+               char *arg = *argv++;
 
                if (*arg == '-') {
-                       if (!strncmp(arg, "--unpack=", 9)) {
-                               unpacker = arg+9;
-                               continue;
-                       }
                        /* Do flag handling here */
                        usage(receive_pack_usage);
                }
+               if (dir)
+                       usage(receive_pack_usage);
                dir = arg;
-               heads = argv;
-               nr_heads = argc - i - 1;
-               break;
        }
        if (!dir)
                usage(receive_pack_usage);
 
-       /* chdir to the directory. If that fails, try appending ".git" */
-       if (chdir(dir) < 0) {
-               static char path[PATH_MAX];
-               snprintf(path, sizeof(path), "%s.git", dir);
-               if (chdir(path) < 0)
-                       die("unable to cd to %s", dir);
-       }
-
-       /* If we have a ".git" directory, chdir to it */
-       chdir(".git");
+       if(!enter_repo(dir, 0))
+               die("'%s': unable to chdir or not a git archive", dir);
 
-       if (access("objects", X_OK) < 0 || access("refs/heads", X_OK) < 0)
-               die("%s doesn't appear to be a git directory", dir);
-       write_head_info("refs/", nr_heads, heads);
+       write_head_info();
 
        /* EOF */
-       safe_write(1, "0000", 4);
-       flush_safe(1);
+       packet_flush(1);
 
        read_head_info();
-       unpack();
-       execute_commands();
+       if (commands) {
+               unpack();
+               execute_commands();
+       }
        return 0;
 }