_GIT_INDEX_OUTPUT: allow plumbing to output to an alternative index file.
[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;
7
8static 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
17static void remove_lock_file_on_signal(int signo)
18{
19 remove_lock_file();
20 signal(SIGINT, SIG_DFL);
21 raise(signo);
22}
23
40aaae88 24static int lock_file(struct lock_file *lk, const char *path)
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25{
26 int fd;
27 sprintf(lk->filename, "%s.lock", path);
28 fd = open(lk->filename, O_RDWR | O_CREAT | O_EXCL, 0666);
138086a7 29 if (0 <= fd) {
1084b845 30 if (!lk->on_list) {
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31 lk->next = lock_file_list;
32 lock_file_list = lk;
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33 lk->on_list = 1;
34 }
35 if (lock_file_list) {
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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);
021b6e45 42 }
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43 else
44 lk->filename[0] = 0;
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45 return fd;
46}
47
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48int 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)
f9e8a43a 52 die("unable to create '%s.lock': %s", path, strerror(errno));
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53 return fd;
54}
55
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56int 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
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68int hold_locked_index(struct lock_file *lk, int die_on_error)
69{
70 return hold_lock_file_for_update(lk, get_index_file(), die_on_error);
71}
72
73int commit_locked_index(struct lock_file *lk)
74{
75 char *output = getenv(INDEX_OUTPUT_ENVIRONMENT);
76 if (output && *output) {
77 int result = rename(lk->filename, output);
78 lk->filename[0] = 0;
79 return result;
80 }
81 else
82 return commit_lock_file(lk);
83}
84
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85void rollback_lock_file(struct lock_file *lk)
86{
87 if (lk->filename[0])
88 unlink(lk->filename);
89 lk->filename[0] = 0;
90}
91