From d6cf61bfd4bccffcc8b095f8469dbe749d70abdf Mon Sep 17 00:00:00 2001 From: Brandon Casey Date: Wed, 16 Jan 2008 11:05:32 -0800 Subject: [PATCH] close_lock_file(): new function in the lockfile API The lockfile API is a handy way to obtain a file that is cleaned up if you die(). But sometimes you would need this sequence to work: 1. hold_lock_file_for_update() to get a file descriptor for writing; 2. write the contents out, without being able to decide if the results should be committed or rolled back; 3. do something else that makes the decision --- and this "something else" needs the lockfile not to have an open file descriptor for writing (e.g. Windows do not want a open file to be renamed); 4. call commit_lock_file() or rollback_lock_file() as appropriately. This adds close_lock_file() you can call between step 2 and 3 in the above sequence. Signed-off-by: Junio C Hamano --- Documentation/technical/api-lockfile.txt | 15 +++++++++--- cache.h | 2 +- lockfile.c | 30 +++++++++++++++++------- 3 files changed, 35 insertions(+), 12 deletions(-) diff --git a/Documentation/technical/api-lockfile.txt b/Documentation/technical/api-lockfile.txt index 5b1553e52c..dd894043ae 100644 --- a/Documentation/technical/api-lockfile.txt +++ b/Documentation/technical/api-lockfile.txt @@ -37,7 +37,8 @@ commit_lock_file:: Take a pointer to the `struct lock_file` initialized with an earlier call to `hold_lock_file_for_update()`, close the file descriptor and rename the lockfile to its - final destination. + final destination. Returns 0 upon success, a negative + value on failure to close(2) or rename(2). rollback_lock_file:: @@ -45,6 +46,12 @@ rollback_lock_file:: with an earlier call to `hold_lock_file_for_update()`, close the file descriptor and remove the lockfile. +close_lock_file:: + Take a pointer to the `struct lock_file` initialized + with an earlier call to `hold_lock_file_for_update()`, + and close the file descriptor. Returns 0 upon success, + a negative value on failure to close(2). + Because the structure is used in an `atexit(3)` handler, its storage has to stay throughout the life of the program. It cannot be an auto variable allocated on the stack. @@ -54,8 +61,10 @@ done writing to the file descriptor. If you do not call either and simply `exit(3)` from the program, an `atexit(3)` handler will close and remove the lockfile. -You should not close the file descriptor you obtained from -`hold_lock_file_for_update` function yourself. The `struct +If you need to close the file descriptor you obtained from +`hold_lock_file_for_update` function yourself, do so by calling +`close_lock_file()`. You should never call `close(2)` yourself! +Otherwise the `struct lock_file` structure still remembers that the file descriptor needs to be closed, and a later call to `commit_lock_file()` or `rollback_lock_file()` will result in duplicate calls to diff --git a/cache.h b/cache.h index 39331c28be..24735bdfee 100644 --- a/cache.h +++ b/cache.h @@ -308,7 +308,7 @@ extern int commit_lock_file(struct lock_file *); extern int hold_locked_index(struct lock_file *, int); extern int commit_locked_index(struct lock_file *); extern void set_alternate_index_output(const char *); - +extern int close_lock_file(struct lock_file *); extern void rollback_lock_file(struct lock_file *); extern int delete_ref(const char *, const unsigned char *sha1); diff --git a/lockfile.c b/lockfile.c index f45d3ed544..663f18f9c4 100644 --- a/lockfile.c +++ b/lockfile.c @@ -13,7 +13,8 @@ static void remove_lock_file(void) while (lock_file_list) { if (lock_file_list->owner == me && lock_file_list->filename[0]) { - close(lock_file_list->fd); + if (lock_file_list->fd >= 0) + close(lock_file_list->fd); unlink(lock_file_list->filename); } lock_file_list = lock_file_list->next; @@ -159,17 +160,26 @@ int hold_lock_file_for_update(struct lock_file *lk, const char *path, int die_on 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]; - int i; - close(lk->fd); + 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; - i = rename(lk->filename, result_file); + if (rename(lk->filename, result_file)) + return -1; lk->filename[0] = 0; - return i; + return 0; } int hold_locked_index(struct lock_file *lk, int die_on_error) @@ -185,9 +195,12 @@ void set_alternate_index_output(const char *name) int commit_locked_index(struct lock_file *lk) { if (alternate_index_output) { - int result = rename(lk->filename, 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 result; + return 0; } else return commit_lock_file(lk); @@ -196,7 +209,8 @@ int commit_locked_index(struct lock_file *lk) void rollback_lock_file(struct lock_file *lk) { if (lk->filename[0]) { - close(lk->fd); + if (lk->fd >= 0) + close(lk->fd); unlink(lk->filename); } lk->filename[0] = 0; -- 2.39.2