When locking in a symlinked repository, try to lock the original.
[git/git.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 pid_t me = getpid();
12
13 while (lock_file_list) {
14 if (lock_file_list->owner == me &&
15 lock_file_list->filename[0])
16 unlink(lock_file_list->filename);
17 lock_file_list = lock_file_list->next;
18 }
19 }
20
21 static void remove_lock_file_on_signal(int signo)
22 {
23 remove_lock_file();
24 signal(SIGINT, SIG_DFL);
25 raise(signo);
26 }
27
28 static int lock_file(struct lock_file *lk, const char *path)
29 {
30 int fd;
31 struct stat st;
32
33 if ((!lstat(path, &st)) && S_ISLNK(st.st_mode)) {
34 ssize_t sz;
35 static char target[PATH_MAX];
36 sz = readlink(path, target, sizeof(target));
37 if (sz < 0)
38 warning("Cannot readlink %s", path);
39 else if (target[0] != '/')
40 warning("Cannot lock target of relative symlink %s", path);
41 else
42 path = target;
43 }
44 sprintf(lk->filename, "%s.lock", path);
45 fd = open(lk->filename, O_RDWR | O_CREAT | O_EXCL, 0666);
46 if (0 <= fd) {
47 if (!lock_file_list) {
48 signal(SIGINT, remove_lock_file_on_signal);
49 atexit(remove_lock_file);
50 }
51 lk->owner = getpid();
52 if (!lk->on_list) {
53 lk->next = lock_file_list;
54 lock_file_list = lk;
55 lk->on_list = 1;
56 }
57 if (adjust_shared_perm(lk->filename))
58 return error("cannot fix permission bits on %s",
59 lk->filename);
60 }
61 else
62 lk->filename[0] = 0;
63 return fd;
64 }
65
66 int hold_lock_file_for_update(struct lock_file *lk, const char *path, int die_on_error)
67 {
68 int fd = lock_file(lk, path);
69 if (fd < 0 && die_on_error)
70 die("unable to create '%s.lock': %s", path, strerror(errno));
71 return fd;
72 }
73
74 int commit_lock_file(struct lock_file *lk)
75 {
76 char result_file[PATH_MAX];
77 int i;
78 strcpy(result_file, lk->filename);
79 i = strlen(result_file) - 5; /* .lock */
80 result_file[i] = 0;
81 i = rename(lk->filename, result_file);
82 lk->filename[0] = 0;
83 return i;
84 }
85
86 int hold_locked_index(struct lock_file *lk, int die_on_error)
87 {
88 return hold_lock_file_for_update(lk, get_index_file(), die_on_error);
89 }
90
91 void set_alternate_index_output(const char *name)
92 {
93 alternate_index_output = name;
94 }
95
96 int commit_locked_index(struct lock_file *lk)
97 {
98 if (alternate_index_output) {
99 int result = rename(lk->filename, alternate_index_output);
100 lk->filename[0] = 0;
101 return result;
102 }
103 else
104 return commit_lock_file(lk);
105 }
106
107 void rollback_lock_file(struct lock_file *lk)
108 {
109 if (lk->filename[0])
110 unlink(lk->filename);
111 lk->filename[0] = 0;
112 }