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                         unlink(lock_file_list->filename);
  13                 lock_file_list = lock_file_list->next;
  14         }
  15 }
  16
  17 static void remove_lock_file_on_signal(int signo)
  18 {
  19         remove_lock_file();
  20         signal(SIGINT, SIG_DFL);
  21         raise(signo);
  22 }
  23
  24 static int lock_file(struct lock_file *lk, const char *path)
  25 {
  26         int fd;
  27         sprintf(lk->filename, "%s.lock", path);
  28         fd = open(lk->filename, O_RDWR | O_CREAT | O_EXCL, 0666);
  29         if (0 <= fd) {
  30                 if (!lk->next) {
  31                         lk->next = lock_file_list;
  32                         lock_file_list = lk;
  33                         signal(SIGINT, remove_lock_file_on_signal);
  34                         atexit(remove_lock_file);
  35                 }
  36                 if (adjust_shared_perm(lk->filename))
  37                         return error("cannot fix permission bits on %s",
  38                                      lk->filename);
  39         }
  40         return fd;
  41 }
  42
  43 int hold_lock_file_for_update(struct lock_file *lk, const char *path, int die_on_error)
  44 {
  45         int fd = lock_file(lk, path);
  46         if (fd < 0 && die_on_error)
  47                 die("unable to create '%s': %s", path, strerror(errno));
  48         return fd;
  49 }
  50
  51 int commit_lock_file(struct lock_file *lk)
  52 {
  53         char result_file[PATH_MAX];
  54         int i;
  55         strcpy(result_file, lk->filename);
  56         i = strlen(result_file) - 5; /* .lock */
  57         result_file[i] = 0;
  58         i = rename(lk->filename, result_file);
  59         lk->filename[0] = 0;
  60         return i;
  61 }
  62
  63 void rollback_lock_file(struct lock_file *lk)
  64 {
  65         if (lk->filename[0])
  66                 unlink(lk->filename);
  67         lk->filename[0] = 0;
  68 }
  69