diff options
Diffstat (limited to 'sysdeps/generic/utmp_file.c')
| -rw-r--r-- | sysdeps/generic/utmp_file.c | 34 |
1 files changed, 24 insertions, 10 deletions
diff --git a/sysdeps/generic/utmp_file.c b/sysdeps/generic/utmp_file.c index 169f0c7363..6502ac3524 100644 --- a/sysdeps/generic/utmp_file.c +++ b/sysdeps/generic/utmp_file.c @@ -47,6 +47,15 @@ static struct utmp last_entry; /* Do-nothing handler for locking timeout. */ static void timeout_handler (int signum) {}; +/* LOCK_FILE(fd, type) failure_statement + attempts to get a lock on the utmp file referenced by FD. If it fails, + the failure_statement is executed, otherwise it is skipped. + LOCKING_FAILED() + jumps into the UNLOCK_FILE macro and ensures cleanup of LOCK_FILE. + UNLOCK_FILE(fd) + unlocks the utmp file referenced by FD and performs the cleanup of + LOCK_FILE. + */ #define LOCK_FILE(fd, type) \ { \ struct flock fl; \ @@ -70,11 +79,15 @@ static void timeout_handler (int signum) {}; fl.l_whence = SEEK_SET; \ if (__fcntl ((fd), F_SETLKW, &fl) < 0) +#define LOCKING_FAILED() \ + goto unalarm_return + #define UNLOCK_FILE(fd) \ /* Unlock the file. */ \ fl.l_type = F_UNLCK; \ __fcntl ((fd), F_SETLKW, &fl); \ \ + unalarm_return: \ /* Reset the signal handler and alarm. We must reset the alarm \ before resetting the handler so our alarm does not generate a \ spurious SIGALRM seen by the user. However, we cannot just set \ @@ -179,8 +192,8 @@ getutent_r_file (struct utmp *buffer, struct utmp **result) LOCK_FILE (file_fd, F_RDLCK) { - *result = NULL; - return -1; + nbytes = 0; + LOCKING_FAILED (); } /* Read the next entry. */ @@ -190,7 +203,8 @@ getutent_r_file (struct utmp *buffer, struct utmp **result) if (nbytes != sizeof (struct utmp)) { - file_offset = -1l; + if (nbytes != 0) + file_offset = -1l; *result = NULL; return -1; } @@ -211,7 +225,7 @@ internal_getut_r (const struct utmp *id, struct utmp *buffer) int result = -1; LOCK_FILE (file_fd, F_RDLCK) - return result; + LOCKING_FAILED (); #if _HAVE_UT_TYPE - 0 if (id->ut_type == RUN_LVL || id->ut_type == BOOT_TIME @@ -312,7 +326,7 @@ getutline_r_file (const struct utmp *line, struct utmp *buffer, LOCK_FILE (file_fd, F_RDLCK) { *result = NULL; - return -1; + LOCKING_FAILED (); } while (1) @@ -375,7 +389,10 @@ pututline_file (const struct utmp *data) found = internal_getut_r (data, &buffer); LOCK_FILE (file_fd, F_WRLCK) - return NULL; + { + pbuf = NULL; + LOCKING_FAILED (); + } if (found < 0) { @@ -445,10 +462,7 @@ updwtmp_file (const char *file, const struct utmp *utmp) return -1; LOCK_FILE (fd, F_WRLCK) - { - __close (fd); - return result; - } + LOCKING_FAILED (); /* Remember original size of log file. */ offset = __lseek64 (fd, 0, SEEK_END); |