#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);
}
static char *last_path_elm(char *p)
{
char *r = strchr(p, '\0');
if (r == p)
return p;
r--;
while (r > p && *r == '/')
r--;
while (r > p && *(r-1) != '/')
r--;
return r;
}
#define MAXDEPTH 5
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) {
return p;
}
else if (link_len < sizeof(link))
link[link_len] = '\0';
else {
warning("%s: symlink too long", p);
return p;
}
if (is_absolute_path(link)) {
if (link_len < s)
strcpy(p, link);
else {
warning("%s: symlink too long", p);
return p;
}
} else {
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)
{
static const size_t max_path_len = sizeof(lk->filename) - 5;
if (strlen(path) >= max_path_len)
return -1;
strcpy(lk->filename, path);
if (!(flags & LOCK_NODEREF))
resolve_symlink(lk->filename, max_path_len);
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;
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;
}