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->on_list) {
  31                         lk->next = lock_file_list;
  32                         lock_file_list = lk;
  33                         lk->on_list = 1;
  34                 }
  35                 if (lock_file_list) {
  36                         signal(SIGINT, remove_lock_file_on_signal);
  37                         atexit(remove_lock_file);
  38                 }
  39                 if (adjust_shared_perm(lk->filename))
  40                         return error("cannot fix permission bits on %s",
  41                                      lk->filename);
  42         }
  43         else
  44                 lk->filename[0] = 0;
  45         return fd;
  46 }
  47
  48 int hold_lock_file_for_update(struct lock_file *lk, const char *path, int die_on_error)
  49 {
  50         int fd = lock_file(lk, path);
  51         if (fd < 0 && die_on_error)
  52                 die("unable to create '%s.lock': %s", path, strerror(errno));
  53         return fd;
  54 }
  55
  56 int commit_lock_file(struct lock_file *lk)
  57 {
  58         char result_file[PATH_MAX];
  59         int i;
  60         strcpy(result_file, lk->filename);
  61         i = strlen(result_file) - 5; /* .lock */
  62         result_file[i] = 0;
  63         i = rename(lk->filename, result_file);
  64         lk->filename[0] = 0;
  65         return i;
  66 }
  67
  68 void rollback_lock_file(struct lock_file *lk)
  69 {
  70         if (lk->filename[0])
  71                 unlink(lk->filename);
  72         lk->filename[0] = 0;
  73 }
  74