mirror of
https://github.com/git/git.git
synced 2024-10-30 13:57:54 +01:00
fb43bd1cd1
The former caller uses unable_to_lock_message now. Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Reviewed-by: Ronnie Sahlberg <sahlberg@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
87 lines
3.3 KiB
C
87 lines
3.3 KiB
C
#ifndef LOCKFILE_H
|
|
#define LOCKFILE_H
|
|
|
|
/*
|
|
* File write-locks as used by Git.
|
|
*
|
|
* For an overview of how to use the lockfile API, please see
|
|
*
|
|
* Documentation/technical/api-lockfile.txt
|
|
*
|
|
* This module keeps track of all locked files in lock_file_list for
|
|
* use at cleanup. This list and the lock_file objects that comprise
|
|
* it must be kept in self-consistent states at all time, because the
|
|
* program can be interrupted any time by a signal, in which case the
|
|
* signal handler will walk through the list attempting to clean up
|
|
* any open lock files.
|
|
*
|
|
* A lockfile is owned by the process that created it. The lock_file
|
|
* object has an "owner" field that records its owner. This field is
|
|
* used to prevent a forked process from closing a lockfile created by
|
|
* its parent.
|
|
*
|
|
* The possible states of a lock_file object are as follows:
|
|
*
|
|
* - Uninitialized. In this state the object's on_list field must be
|
|
* zero but the rest of its contents need not be initialized. As
|
|
* soon as the object is used in any way, it is irrevocably
|
|
* registered in the lock_file_list, and on_list is set.
|
|
*
|
|
* - Locked, lockfile open (after hold_lock_file_for_update(),
|
|
* hold_lock_file_for_append(), or reopen_lock_file()). In this
|
|
* state:
|
|
* - the lockfile exists
|
|
* - active is set
|
|
* - filename holds the filename of the lockfile
|
|
* - fd holds a file descriptor open for writing to the lockfile
|
|
* - fp holds a pointer to an open FILE object if and only if
|
|
* fdopen_lock_file() has been called on the object
|
|
* - owner holds the PID of the process that locked the file
|
|
*
|
|
* - Locked, lockfile closed (after successful close_lock_file()).
|
|
* Same as the previous state, except that the lockfile is closed
|
|
* and fd is -1.
|
|
*
|
|
* - Unlocked (after commit_lock_file(), commit_lock_file_to(),
|
|
* rollback_lock_file(), a failed attempt to lock, or a failed
|
|
* close_lock_file()). In this state:
|
|
* - active is unset
|
|
* - filename is empty (usually, though there are transitory
|
|
* states in which this condition doesn't hold). Client code should
|
|
* *not* rely on the filename being empty in this state.
|
|
* - fd is -1
|
|
* - the object is left registered in the lock_file_list, and
|
|
* on_list is set.
|
|
*/
|
|
|
|
struct lock_file {
|
|
struct lock_file *volatile next;
|
|
volatile sig_atomic_t active;
|
|
volatile int fd;
|
|
FILE *volatile fp;
|
|
volatile pid_t owner;
|
|
char on_list;
|
|
struct strbuf filename;
|
|
};
|
|
|
|
/* String appended to a filename to derive the lockfile name: */
|
|
#define LOCK_SUFFIX ".lock"
|
|
#define LOCK_SUFFIX_LEN 5
|
|
|
|
#define LOCK_DIE_ON_ERROR 1
|
|
#define LOCK_NO_DEREF 2
|
|
|
|
extern void unable_to_lock_message(const char *path, int err,
|
|
struct strbuf *buf);
|
|
extern NORETURN void unable_to_lock_die(const char *path, int err);
|
|
extern int hold_lock_file_for_update(struct lock_file *, const char *path, int);
|
|
extern int hold_lock_file_for_append(struct lock_file *, const char *path, int);
|
|
extern FILE *fdopen_lock_file(struct lock_file *, const char *mode);
|
|
extern char *get_locked_file_path(struct lock_file *);
|
|
extern int commit_lock_file_to(struct lock_file *, const char *path);
|
|
extern int commit_lock_file(struct lock_file *);
|
|
extern int reopen_lock_file(struct lock_file *);
|
|
extern int close_lock_file(struct lock_file *);
|
|
extern void rollback_lock_file(struct lock_file *);
|
|
|
|
#endif /* LOCKFILE_H */
|