Skip to content
This repository

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
tag: v1.8.0-rc2
Fetching contributors…

Octocat-spinner-32-eaf2f5

Cannot retrieve contributors at this time

file 281 lines (249 sloc) 6.389 kb
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280
/*
* Copyright (c) 2005, Junio C Hamano
*/
#include "cache.h"
#include "sigchain.h"

static struct lock_file *lock_file_list;
static const char *alternate_index_output;

static void remove_lock_file(void)
{
pid_t me = getpid();

while (lock_file_list) {
if (lock_file_list->owner == me &&
lock_file_list->filename[0]) {
if (lock_file_list->fd >= 0)
close(lock_file_list->fd);
unlink_or_warn(lock_file_list->filename);
}
lock_file_list = lock_file_list->next;
}
}

static void remove_lock_file_on_signal(int signo)
{
remove_lock_file();
sigchain_pop(signo);
raise(signo);
}

/*
* p = absolute or relative path name
*
* Return a pointer into p showing the beginning of the last path name
* element. If p is empty or the root directory ("/"), just return p.
*/
static char *last_path_elm(char *p)
{
/* r starts pointing to null at the end of the string */
char *r = strchr(p, '\0');

if (r == p)
return p; /* just return empty string */

r--; /* back up to last non-null character */

/* back up past trailing slashes, if any */
while (r > p && *r == '/')
r--;

/*
* then go backwards until I hit a slash, or the beginning of
* the string
*/
while (r > p && *(r-1) != '/')
r--;
return r;
}


/* We allow "recursive" symbolic links. Only within reason, though */
#define MAXDEPTH 5

/*
* p = path that may be a symlink
* s = full size of p
*
* If p is a symlink, attempt to overwrite p with a path to the real
* file or directory (which may or may not exist), following a chain of
* symlinks if necessary. Otherwise, leave p unmodified.
*
* This is a best-effort routine. If an error occurs, p will either be
* left unmodified or will name a different symlink in a symlink chain
* that started with p's initial contents.
*
* Always returns p.
*/

static char *resolve_symlink(char *p, size_t s)
{
int depth = MAXDEPTH;

while (depth--) {
char link[PATH_MAX];
int link_len = readlink(p, link, sizeof(link));
if (link_len < 0) {
/* not a symlink anymore */
return p;
}
else if (link_len < sizeof(link))
/* readlink() never null-terminates */
link[link_len] = '\0';
else {
warning("%s: symlink too long", p);
return p;
}

if (is_absolute_path(link)) {
/* absolute path simply replaces p */
if (link_len < s)
strcpy(p, link);
else {
warning("%s: symlink too long", p);
return p;
}
} else {
/*
* link is a relative path, so I must replace the
* last element of p with it.
*/
char *r = (char *)last_path_elm(p);
if (r - p + link_len < s)
strcpy(r, link);
else {
warning("%s: symlink too long", p);
return p;
}
}
}
return p;
}


static int lock_file(struct lock_file *lk, const char *path, int flags)
{
if (strlen(path) >= sizeof(lk->filename))
return -1;
strcpy(lk->filename, path);
/*
* subtract 5 from size to make sure there's room for adding
* ".lock" for the lock file name
*/
if (!(flags & LOCK_NODEREF))
resolve_symlink(lk->filename, sizeof(lk->filename)-5);
strcat(lk->filename, ".lock");
lk->fd = open(lk->filename, O_RDWR | O_CREAT | O_EXCL, 0666);
if (0 <= lk->fd) {
if (!lock_file_list) {
sigchain_push_common(remove_lock_file_on_signal);
atexit(remove_lock_file);
}
lk->owner = getpid();
if (!lk->on_list) {
lk->next = lock_file_list;
lock_file_list = lk;
lk->on_list = 1;
}
if (adjust_shared_perm(lk->filename))
return error("cannot fix permission bits on %s",
lk->filename);
}
else
lk->filename[0] = 0;
return lk->fd;
}

static char *unable_to_lock_message(const char *path, int err)
{
struct strbuf buf = STRBUF_INIT;

if (err == EEXIST) {
strbuf_addf(&buf, "Unable to create '%s.lock': %s.\n\n"
"If no other git process is currently running, this probably means a\n"
"git process crashed in this repository earlier. Make sure no other git\n"
"process is running and remove the file manually to continue.",
absolute_path(path), strerror(err));
} else
strbuf_addf(&buf, "Unable to create '%s.lock': %s",
absolute_path(path), strerror(err));
return strbuf_detach(&buf, NULL);
}

int unable_to_lock_error(const char *path, int err)
{
char *msg = unable_to_lock_message(path, err);
error("%s", msg);
free(msg);
return -1;
}

NORETURN void unable_to_lock_index_die(const char *path, int err)
{
die("%s", unable_to_lock_message(path, err));
}

int hold_lock_file_for_update(struct lock_file *lk, const char *path, int flags)
{
int fd = lock_file(lk, path, flags);
if (fd < 0 && (flags & LOCK_DIE_ON_ERROR))
unable_to_lock_index_die(path, errno);
return fd;
}

int hold_lock_file_for_append(struct lock_file *lk, const char *path, int flags)
{
int fd, orig_fd;

fd = lock_file(lk, path, flags);
if (fd < 0) {
if (flags & LOCK_DIE_ON_ERROR)
unable_to_lock_index_die(path, errno);
return fd;
}

orig_fd = open(path, O_RDONLY);
if (orig_fd < 0) {
if (errno != ENOENT) {
if (flags & LOCK_DIE_ON_ERROR)
die("cannot open '%s' for copying", path);
close(fd);
return error("cannot open '%s' for copying", path);
}
} else if (copy_fd(orig_fd, fd)) {
if (flags & LOCK_DIE_ON_ERROR)
exit(128);
close(fd);
return -1;
}
return fd;
}

int close_lock_file(struct lock_file *lk)
{
int fd = lk->fd;
lk->fd = -1;
return close(fd);
}

int commit_lock_file(struct lock_file *lk)
{
char result_file[PATH_MAX];
size_t i;
if (lk->fd >= 0 && close_lock_file(lk))
return -1;
strcpy(result_file, lk->filename);
i = strlen(result_file) - 5; /* .lock */
result_file[i] = 0;
if (rename(lk->filename, result_file))
return -1;
lk->filename[0] = 0;
return 0;
}

int hold_locked_index(struct lock_file *lk, int die_on_error)
{
return hold_lock_file_for_update(lk, get_index_file(),
die_on_error
? LOCK_DIE_ON_ERROR
: 0);
}

void set_alternate_index_output(const char *name)
{
alternate_index_output = name;
}

int commit_locked_index(struct lock_file *lk)
{
if (alternate_index_output) {
if (lk->fd >= 0 && close_lock_file(lk))
return -1;
if (rename(lk->filename, alternate_index_output))
return -1;
lk->filename[0] = 0;
return 0;
}
else
return commit_lock_file(lk);
}

void rollback_lock_file(struct lock_file *lk)
{
if (lk->filename[0]) {
if (lk->fd >= 0)
close(lk->fd);
unlink_or_warn(lk->filename);
}
lk->filename[0] = 0;
}
Something went wrong with that request. Please try again.