lockfile.c

   1 /*
   2  * Copyright (c) 2005, Junio C Hamano
   3  */
   4 #include "cache.h"
   5
   6 static struct lock_file *lock_file_list;
   7
   8 static void remove_lock_file(void)
   9 {
  10         while (lock_file_list) {
  11                 if (lock_file_list->filename[0]) {
  12                         close(lock_file_list->fd);
  13                         unlink(lock_file_list->filename);
  14                 }
  15                 lock_file_list = lock_file_list->next;
  16         }
  17 }
  18
  19 static void remove_lock_file_on_signal(int signo)
  20 {
  21         remove_lock_file();
  22         signal(SIGINT, SIG_DFL);
  23         raise(signo);
  24 }
  25
  26 static int lock_file(struct lock_file *lk, const char *path)
  27 {
  28         sprintf(lk->filename, "%s.lock", path);
  29         lk->fd = open(lk->filename, O_RDWR | O_CREAT | O_EXCL, 0666);
  30         if (0 <= lk->fd) {
  31                 if (!lk->on_list) {
  32                         lk->next = lock_file_list;
  33                         lock_file_list = lk;
  34                         lk->on_list = 1;
  35                 }
  36                 if (lock_file_list) {
  37                         signal(SIGINT, remove_lock_file_on_signal);
  38                         atexit(remove_lock_file);
  39                 }
  40                 if (adjust_shared_perm(lk->filename))
  41                         return error("cannot fix permission bits on %s",
  42                                      lk->filename);
  43         }
  44         else
  45                 lk->filename[0] = 0;
  46         return lk->fd;
  47 }
  48
  49 int hold_lock_file_for_update(struct lock_file *lk, const char *path, int die_on_error)
  50 {
  51         int fd = lock_file(lk, path);
  52         if (fd < 0 && die_on_error)
  53                 die("unable to create '%s.lock': %s", path, strerror(errno));
  54         return fd;
  55 }
  56
  57 int commit_lock_file(struct lock_file *lk)
  58 {
  59         char result_file[PATH_MAX];
  60         int i;
  61         close(lk->fd);
  62         strcpy(result_file, lk->filename);
  63         i = strlen(result_file) - 5; /* .lock */
  64         result_file[i] = 0;
  65         unlink(result_file);
  66         i = rename(lk->filename, result_file);
  67         lk->filename[0] = 0;
  68         return i;
  69 }
  70
  71 void rollback_lock_file(struct lock_file *lk)
  72 {
  73         if (lk->filename[0]) {
  74                 close(lk->fd);
  75                 unlink(lk->filename);
  76         }
  77         lk->filename[0] = 0;
  78 }
  79