When locking in a symlinked repository, try to lock the original.
[git/git.git] / lockfile.c
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1/*
2 * Copyright (c) 2005, Junio C Hamano
3 */
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4#include "cache.h"
5
6static struct lock_file *lock_file_list;
5e7f56ac 7static const char *alternate_index_output;
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8
9static void remove_lock_file(void)
10{
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11 pid_t me = getpid();
12
021b6e45 13 while (lock_file_list) {
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14 if (lock_file_list->owner == me &&
15 lock_file_list->filename[0])
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16 unlink(lock_file_list->filename);
17 lock_file_list = lock_file_list->next;
18 }
19}
20
21static void remove_lock_file_on_signal(int signo)
22{
23 remove_lock_file();
24 signal(SIGINT, SIG_DFL);
25 raise(signo);
26}
27
40aaae88 28static int lock_file(struct lock_file *lk, const char *path)
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29{
30 int fd;
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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 }
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44 sprintf(lk->filename, "%s.lock", path);
45 fd = open(lk->filename, O_RDWR | O_CREAT | O_EXCL, 0666);
138086a7 46 if (0 <= fd) {
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47 if (!lock_file_list) {
48 signal(SIGINT, remove_lock_file_on_signal);
49 atexit(remove_lock_file);
50 }
5e635e39 51 lk->owner = getpid();
1084b845 52 if (!lk->on_list) {
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53 lk->next = lock_file_list;
54 lock_file_list = lk;
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55 lk->on_list = 1;
56 }
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57 if (adjust_shared_perm(lk->filename))
58 return error("cannot fix permission bits on %s",
59 lk->filename);
021b6e45 60 }
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61 else
62 lk->filename[0] = 0;
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63 return fd;
64}
65
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66int 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)
f9e8a43a 70 die("unable to create '%s.lock': %s", path, strerror(errno));
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71 return fd;
72}
73
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74int 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
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86int 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
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91void set_alternate_index_output(const char *name)
92{
93 alternate_index_output = name;
94}
95
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96int commit_locked_index(struct lock_file *lk)
97{
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98 if (alternate_index_output) {
99 int result = rename(lk->filename, alternate_index_output);
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100 lk->filename[0] = 0;
101 return result;
102 }
103 else
104 return commit_lock_file(lk);
105}
106
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107void rollback_lock_file(struct lock_file *lk)
108{
109 if (lk->filename[0])
110 unlink(lk->filename);
111 lk->filename[0] = 0;
112}