lockfile.c

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