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![Junio C Hamano](/assets/img/avatar_default.png)
This changes the "die_on_error" boolean parameter to a mere "flags", and changes the existing callers of hold_lock_file_for_update/append() functions to pass LOCK_DIE_ON_ERROR. Signed-off-by: Junio C Hamano <gitster@pobox.com>
254 lines
5.5 KiB
C
254 lines
5.5 KiB
C
/*
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* Copyright (c) 2005, Junio C Hamano
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*/
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#include "cache.h"
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static struct lock_file *lock_file_list;
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static const char *alternate_index_output;
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static void remove_lock_file(void)
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{
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pid_t me = getpid();
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while (lock_file_list) {
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if (lock_file_list->owner == me &&
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lock_file_list->filename[0]) {
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if (lock_file_list->fd >= 0)
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close(lock_file_list->fd);
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unlink(lock_file_list->filename);
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}
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lock_file_list = lock_file_list->next;
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}
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}
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static void remove_lock_file_on_signal(int signo)
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{
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remove_lock_file();
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signal(signo, SIG_DFL);
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raise(signo);
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}
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/*
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* p = absolute or relative path name
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*
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* Return a pointer into p showing the beginning of the last path name
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* element. If p is empty or the root directory ("/"), just return p.
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*/
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static char *last_path_elm(char *p)
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{
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/* r starts pointing to null at the end of the string */
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char *r = strchr(p, '\0');
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if (r == p)
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return p; /* just return empty string */
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r--; /* back up to last non-null character */
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/* back up past trailing slashes, if any */
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while (r > p && *r == '/')
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r--;
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/*
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* then go backwards until I hit a slash, or the beginning of
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* the string
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*/
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while (r > p && *(r-1) != '/')
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r--;
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return r;
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}
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/* We allow "recursive" symbolic links. Only within reason, though */
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#define MAXDEPTH 5
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/*
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* p = path that may be a symlink
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* s = full size of p
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*
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* If p is a symlink, attempt to overwrite p with a path to the real
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* file or directory (which may or may not exist), following a chain of
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* symlinks if necessary. Otherwise, leave p unmodified.
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*
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* This is a best-effort routine. If an error occurs, p will either be
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* left unmodified or will name a different symlink in a symlink chain
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* that started with p's initial contents.
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*
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* Always returns p.
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*/
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static char *resolve_symlink(char *p, size_t s)
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{
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int depth = MAXDEPTH;
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while (depth--) {
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char link[PATH_MAX];
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int link_len = readlink(p, link, sizeof(link));
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if (link_len < 0) {
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/* not a symlink anymore */
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return p;
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}
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else if (link_len < sizeof(link))
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/* readlink() never null-terminates */
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link[link_len] = '\0';
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else {
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warning("%s: symlink too long", p);
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return p;
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}
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if (is_absolute_path(link)) {
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/* absolute path simply replaces p */
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if (link_len < s)
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strcpy(p, link);
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else {
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warning("%s: symlink too long", p);
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return p;
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}
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} else {
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/*
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* link is a relative path, so I must replace the
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* last element of p with it.
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*/
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char *r = (char*)last_path_elm(p);
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if (r - p + link_len < s)
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strcpy(r, link);
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else {
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warning("%s: symlink too long", p);
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return p;
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}
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}
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}
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return p;
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}
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static int lock_file(struct lock_file *lk, const char *path, int flags)
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{
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if (strlen(path) >= sizeof(lk->filename))
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return -1;
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strcpy(lk->filename, path);
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/*
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* subtract 5 from size to make sure there's room for adding
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* ".lock" for the lock file name
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*/
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if (!(flags & LOCK_NODEREF))
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resolve_symlink(lk->filename, sizeof(lk->filename)-5);
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strcat(lk->filename, ".lock");
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lk->fd = open(lk->filename, O_RDWR | O_CREAT | O_EXCL, 0666);
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if (0 <= lk->fd) {
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if (!lock_file_list) {
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signal(SIGINT, remove_lock_file_on_signal);
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signal(SIGHUP, remove_lock_file_on_signal);
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signal(SIGTERM, remove_lock_file_on_signal);
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signal(SIGQUIT, remove_lock_file_on_signal);
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atexit(remove_lock_file);
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}
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lk->owner = getpid();
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if (!lk->on_list) {
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lk->next = lock_file_list;
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lock_file_list = lk;
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lk->on_list = 1;
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}
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if (adjust_shared_perm(lk->filename))
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return error("cannot fix permission bits on %s",
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lk->filename);
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}
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else
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lk->filename[0] = 0;
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return lk->fd;
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}
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int hold_lock_file_for_update(struct lock_file *lk, const char *path, int flags)
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{
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int fd = lock_file(lk, path, flags);
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if (fd < 0 && (flags & LOCK_DIE_ON_ERROR))
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die("unable to create '%s.lock': %s", path, strerror(errno));
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return fd;
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}
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int hold_lock_file_for_append(struct lock_file *lk, const char *path, int flags)
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{
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int fd, orig_fd;
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fd = lock_file(lk, path, flags);
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if (fd < 0) {
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if (flags & LOCK_DIE_ON_ERROR)
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die("unable to create '%s.lock': %s", path, strerror(errno));
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return fd;
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}
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orig_fd = open(path, O_RDONLY);
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if (orig_fd < 0) {
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if (errno != ENOENT) {
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if (flags & LOCK_DIE_ON_ERROR)
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die("cannot open '%s' for copying", path);
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close(fd);
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return error("cannot open '%s' for copying", path);
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}
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} else if (copy_fd(orig_fd, fd)) {
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if (flags & LOCK_DIE_ON_ERROR)
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exit(128);
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close(fd);
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return -1;
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}
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return fd;
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}
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int close_lock_file(struct lock_file *lk)
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{
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int fd = lk->fd;
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lk->fd = -1;
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return close(fd);
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}
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int commit_lock_file(struct lock_file *lk)
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{
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char result_file[PATH_MAX];
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size_t i;
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if (lk->fd >= 0 && close_lock_file(lk))
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return -1;
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strcpy(result_file, lk->filename);
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i = strlen(result_file) - 5; /* .lock */
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result_file[i] = 0;
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if (rename(lk->filename, result_file))
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return -1;
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lk->filename[0] = 0;
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return 0;
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}
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int hold_locked_index(struct lock_file *lk, int die_on_error)
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{
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return hold_lock_file_for_update(lk, get_index_file(),
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die_on_error
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? LOCK_DIE_ON_ERROR
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: 0);
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}
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void set_alternate_index_output(const char *name)
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{
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alternate_index_output = name;
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}
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int commit_locked_index(struct lock_file *lk)
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{
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if (alternate_index_output) {
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if (lk->fd >= 0 && close_lock_file(lk))
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return -1;
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if (rename(lk->filename, alternate_index_output))
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return -1;
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lk->filename[0] = 0;
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return 0;
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}
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else
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return commit_lock_file(lk);
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}
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void rollback_lock_file(struct lock_file *lk)
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{
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if (lk->filename[0]) {
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if (lk->fd >= 0)
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close(lk->fd);
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unlink(lk->filename);
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}
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lk->filename[0] = 0;
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}
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