Merge branch 'maint'
[git] / 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 static const char *alternate_index_output;
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->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 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         strcpy(result_file, lk->filename);
62         i = strlen(result_file) - 5; /* .lock */
63         result_file[i] = 0;
64         i = rename(lk->filename, result_file);
65         lk->filename[0] = 0;
66         return i;
67 }
68
69 int hold_locked_index(struct lock_file *lk, int die_on_error)
70 {
71         return hold_lock_file_for_update(lk, get_index_file(), die_on_error);
72 }
73
74 void set_alternate_index_output(const char *name)
75 {
76         alternate_index_output = name;
77 }
78
79 int commit_locked_index(struct lock_file *lk)
80 {
81         if (alternate_index_output) {
82                 int result = rename(lk->filename, alternate_index_output);
83                 lk->filename[0] = 0;
84                 return result;
85         }
86         else
87                 return commit_lock_file(lk);
88 }
89
90 void rollback_lock_file(struct lock_file *lk)
91 {
92         if (lk->filename[0])
93                 unlink(lk->filename);
94         lk->filename[0] = 0;
95 }
96