file-lock.h revision 65f9a90ef5ed4c86fb9e44f22e472509126ae9f5
#ifndef FILE_LOCK_H
#define FILE_LOCK_H
#include <unistd.h>
#include <fcntl.h>
#define DEFAULT_LOCK_TIMEOUT 120
struct file_lock;
enum file_lock_method {
FILE_LOCK_METHOD_FCNTL,
FILE_LOCK_METHOD_FLOCK,
FILE_LOCK_METHOD_DOTLOCK
};
/* Parse lock method from given string. Returns TRUE if ok,
FALSE if name is unknown. */
bool file_lock_method_parse(const char *name, enum file_lock_method *method_r);
/* Convert lock method to string. */
const char *file_lock_method_to_str(enum file_lock_method method);
/* Lock the file. Returns 1 if successful, 0 if file is already locked,
or -1 if error. lock_type is F_WRLCK or F_RDLCK. */
int file_try_lock(int fd, const char *path, int lock_type,
enum file_lock_method lock_method,
struct file_lock **lock_r);
/* Like file_try_lock(), but return the error message as a string instead
of logging it. Also when returning 0 an error message is returned. */
int file_try_lock_error(int fd, const char *path, int lock_type,
enum file_lock_method lock_method,
struct file_lock **lock_r, const char **error_r);
/* Like lock_try_lock(), but return 0 only after having tried to lock for
timeout_secs. */
int file_wait_lock(int fd, const char *path, int lock_type,
enum file_lock_method lock_method,
unsigned int timeout_secs,
struct file_lock **lock_r);
/* Like file_wait_lock(), but return the error message as a string instead
of logging it. Also when returning 0 an error message is returned. */
int file_wait_lock_error(int fd, const char *path, int lock_type,
enum file_lock_method lock_method,
unsigned int timeout_secs,
struct file_lock **lock_r, const char **error_r);
/* Change the lock type. WARNING: This isn't an atomic operation!
The result is the same as file_unlock() + file_try_lock(). */
int file_lock_try_update(struct file_lock *lock, int lock_type);
/* When the lock is freed, unlink() the file automatically. This can be useful
for files that are only created to exist as lock files. */
void file_lock_set_unlink_on_free(struct file_lock *lock, bool set);
/* When the lock is freed, close the fd automatically. This can
be useful for files that are only created to exist as lock files. */
void file_lock_set_close_on_free(struct file_lock *lock, bool set);
/* Unlock and free the lock. */
void file_unlock(struct file_lock **lock);
/* Free the lock without unlocking it (because you're closing the fd anyway). */
void file_lock_free(struct file_lock **lock);
/* Returns the path given as parameter to file_*lock*(). */
const char *file_lock_get_path(struct file_lock *lock);
/* Update lock file's path (after it gets renamed by the caller). This is
useful mainly together with file_lock_set_unlink_on_free(). */
void file_lock_set_path(struct file_lock *lock, const char *path);
/* Returns human-readable string containing the process that has the file
currently locked. Returns "" if unknown, otherwise " (string)". */
const char *file_lock_find(int lock_fd, enum file_lock_method lock_method,
int lock_type);
/* Track the duration of a lock wait. */
void file_lock_wait_start(void);
void file_lock_wait_end(const char *lock_name);
/* Return how many microseconds has been spent on lock waiting. */
uint64_t file_lock_wait_get_total_usecs(void);
#endif