Fix a bunch of pointer declarations (codestyle)
[git/git.git] / lockfile.c
CommitLineData
021b6e45
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1/*
2 * Copyright (c) 2005, Junio C Hamano
3 */
021b6e45 4#include "cache.h"
4a16d072 5#include "sigchain.h"
021b6e45
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6
7static struct lock_file *lock_file_list;
5e7f56ac 8static const char *alternate_index_output;
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9
10static void remove_lock_file(void)
11{
5e635e39
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12 pid_t me = getpid();
13
021b6e45 14 while (lock_file_list) {
5e635e39 15 if (lock_file_list->owner == me &&
4723ee99 16 lock_file_list->filename[0]) {
d6cf61bf
BC
17 if (lock_file_list->fd >= 0)
18 close(lock_file_list->fd);
021b6e45 19 unlink(lock_file_list->filename);
4723ee99 20 }
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21 lock_file_list = lock_file_list->next;
22 }
23}
24
25static void remove_lock_file_on_signal(int signo)
26{
27 remove_lock_file();
4a16d072 28 sigchain_pop(signo);
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29 raise(signo);
30}
31
5d5a7a67
BS
32/*
33 * p = absolute or relative path name
34 *
35 * Return a pointer into p showing the beginning of the last path name
36 * element. If p is empty or the root directory ("/"), just return p.
37 */
38static char *last_path_elm(char *p)
39{
40 /* r starts pointing to null at the end of the string */
41 char *r = strchr(p, '\0');
42
43 if (r == p)
44 return p; /* just return empty string */
45
46 r--; /* back up to last non-null character */
47
48 /* back up past trailing slashes, if any */
49 while (r > p && *r == '/')
50 r--;
51
52 /*
53 * then go backwards until I hit a slash, or the beginning of
54 * the string
55 */
56 while (r > p && *(r-1) != '/')
57 r--;
58 return r;
59}
60
61
62/* We allow "recursive" symbolic links. Only within reason, though */
63#define MAXDEPTH 5
64
65/*
66 * p = path that may be a symlink
67 * s = full size of p
68 *
69 * If p is a symlink, attempt to overwrite p with a path to the real
70 * file or directory (which may or may not exist), following a chain of
71 * symlinks if necessary. Otherwise, leave p unmodified.
72 *
73 * This is a best-effort routine. If an error occurs, p will either be
74 * left unmodified or will name a different symlink in a symlink chain
75 * that started with p's initial contents.
76 *
77 * Always returns p.
78 */
79
80static char *resolve_symlink(char *p, size_t s)
81{
82 int depth = MAXDEPTH;
83
84 while (depth--) {
85 char link[PATH_MAX];
86 int link_len = readlink(p, link, sizeof(link));
87 if (link_len < 0) {
88 /* not a symlink anymore */
89 return p;
90 }
91 else if (link_len < sizeof(link))
92 /* readlink() never null-terminates */
93 link[link_len] = '\0';
94 else {
95 warning("%s: symlink too long", p);
96 return p;
97 }
98
ecf4831d 99 if (is_absolute_path(link)) {
5d5a7a67
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100 /* absolute path simply replaces p */
101 if (link_len < s)
102 strcpy(p, link);
103 else {
104 warning("%s: symlink too long", p);
105 return p;
106 }
107 } else {
108 /*
109 * link is a relative path, so I must replace the
110 * last element of p with it.
111 */
4b25d091 112 char *r = (char *)last_path_elm(p);
5d5a7a67
BS
113 if (r - p + link_len < s)
114 strcpy(r, link);
115 else {
116 warning("%s: symlink too long", p);
117 return p;
118 }
119 }
120 }
121 return p;
122}
123
124
acd3b9ec 125static int lock_file(struct lock_file *lk, const char *path, int flags)
021b6e45 126{
acd3b9ec
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127 if (strlen(path) >= sizeof(lk->filename))
128 return -1;
5d5a7a67
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129 strcpy(lk->filename, path);
130 /*
131 * subtract 5 from size to make sure there's room for adding
132 * ".lock" for the lock file name
133 */
acd3b9ec
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134 if (!(flags & LOCK_NODEREF))
135 resolve_symlink(lk->filename, sizeof(lk->filename)-5);
5d5a7a67 136 strcat(lk->filename, ".lock");
4723ee99
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137 lk->fd = open(lk->filename, O_RDWR | O_CREAT | O_EXCL, 0666);
138 if (0 <= lk->fd) {
9a4cbdca 139 if (!lock_file_list) {
57b235a4 140 sigchain_push_common(remove_lock_file_on_signal);
9a4cbdca
SV
141 atexit(remove_lock_file);
142 }
5e635e39 143 lk->owner = getpid();
1084b845 144 if (!lk->on_list) {
138086a7
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145 lk->next = lock_file_list;
146 lock_file_list = lk;
1084b845
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147 lk->on_list = 1;
148 }
138086a7
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149 if (adjust_shared_perm(lk->filename))
150 return error("cannot fix permission bits on %s",
151 lk->filename);
021b6e45 152 }
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153 else
154 lk->filename[0] = 0;
4723ee99 155 return lk->fd;
021b6e45
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156}
157
e43a6fd3
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158
159NORETURN void unable_to_lock_index_die(const char *path, int err)
160{
bdfd739d 161 if (err == EEXIST) {
e43a6fd3
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162 die("Unable to create '%s.lock': %s.\n\n"
163 "If no other git process is currently running, this probably means a\n"
164 "git process crashed in this repository earlier. Make sure no other git\n"
165 "process is running and remove the file manually to continue.",
166 path, strerror(err));
167 } else {
168 die("Unable to create '%s.lock': %s", path, strerror(err));
169 }
170}
171
acd3b9ec 172int hold_lock_file_for_update(struct lock_file *lk, const char *path, int flags)
40aaae88 173{
acd3b9ec
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174 int fd = lock_file(lk, path, flags);
175 if (fd < 0 && (flags & LOCK_DIE_ON_ERROR))
e43a6fd3 176 unable_to_lock_index_die(path, errno);
40aaae88
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177 return fd;
178}
179
acd3b9ec 180int hold_lock_file_for_append(struct lock_file *lk, const char *path, int flags)
ea3cd5c7
DB
181{
182 int fd, orig_fd;
183
acd3b9ec 184 fd = lock_file(lk, path, flags);
ea3cd5c7 185 if (fd < 0) {
acd3b9ec 186 if (flags & LOCK_DIE_ON_ERROR)
bdfd739d 187 unable_to_lock_index_die(path, errno);
ea3cd5c7
DB
188 return fd;
189 }
190
191 orig_fd = open(path, O_RDONLY);
192 if (orig_fd < 0) {
193 if (errno != ENOENT) {
acd3b9ec 194 if (flags & LOCK_DIE_ON_ERROR)
ea3cd5c7
DB
195 die("cannot open '%s' for copying", path);
196 close(fd);
197 return error("cannot open '%s' for copying", path);
198 }
199 } else if (copy_fd(orig_fd, fd)) {
acd3b9ec 200 if (flags & LOCK_DIE_ON_ERROR)
ea3cd5c7
DB
201 exit(128);
202 close(fd);
203 return -1;
204 }
205 return fd;
206}
207
d6cf61bf
BC
208int close_lock_file(struct lock_file *lk)
209{
210 int fd = lk->fd;
211 lk->fd = -1;
212 return close(fd);
213}
214
021b6e45
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215int commit_lock_file(struct lock_file *lk)
216{
217 char result_file[PATH_MAX];
d6cf61bf
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218 size_t i;
219 if (lk->fd >= 0 && close_lock_file(lk))
220 return -1;
021b6e45
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221 strcpy(result_file, lk->filename);
222 i = strlen(result_file) - 5; /* .lock */
223 result_file[i] = 0;
d6cf61bf
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224 if (rename(lk->filename, result_file))
225 return -1;
021b6e45 226 lk->filename[0] = 0;
d6cf61bf 227 return 0;
021b6e45
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228}
229
30ca07a2
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230int hold_locked_index(struct lock_file *lk, int die_on_error)
231{
acd3b9ec
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232 return hold_lock_file_for_update(lk, get_index_file(),
233 die_on_error
234 ? LOCK_DIE_ON_ERROR
235 : 0);
30ca07a2
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236}
237
5e7f56ac
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238void set_alternate_index_output(const char *name)
239{
240 alternate_index_output = name;
241}
242
30ca07a2
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243int commit_locked_index(struct lock_file *lk)
244{
5e7f56ac 245 if (alternate_index_output) {
d6cf61bf
BC
246 if (lk->fd >= 0 && close_lock_file(lk))
247 return -1;
248 if (rename(lk->filename, alternate_index_output))
249 return -1;
30ca07a2 250 lk->filename[0] = 0;
d6cf61bf 251 return 0;
30ca07a2
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252 }
253 else
254 return commit_lock_file(lk);
255}
256
021b6e45
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257void rollback_lock_file(struct lock_file *lk)
258{
4723ee99 259 if (lk->filename[0]) {
d6cf61bf
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260 if (lk->fd >= 0)
261 close(lk->fd);
021b6e45 262 unlink(lk->filename);
4723ee99 263 }
021b6e45
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264 lk->filename[0] = 0;
265}