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Diffstat (limited to 'login/logwtmp.c')
-rw-r--r--login/logwtmp.c62
1 files changed, 41 insertions, 21 deletions
diff --git a/login/logwtmp.c b/login/logwtmp.c
index 371f34ee76..2ae6a68dca 100644
--- a/login/logwtmp.c
+++ b/login/logwtmp.c
@@ -17,33 +17,31 @@ License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
+#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <utmp.h>
-
+#include <sys/file.h>
+#include <sys/stat.h>
void
logwtmp (const char *line, const char *name, const char *host)
{
- struct utmp_data data;
struct utmp ut;
+ struct stat st;
+ size_t written;
+ int fd;
- /* Tell that we want to use the UTMP file. */
- if (utmpname (_PATH_WTMP) == 0)
- return;
-
- /* Open UTMP file. */
- setutent_r (&data);
-
- /* Position at end of file. */
- data.loc_utmp = lseek (data.ut_fd, 0, SEEK_END);
- if (data.loc_utmp == -1)
- return;
+ /* Open WTMP file. */
+ fd = __open (_PATH_WTMP, O_WRONLY | O_APPEND);
+ if (fd < 0)
+ return;
/* Set information in new entry. */
- bzero (&ut, sizeof (ut));
+ memset (&ut, 0, sizeof (ut));
+ ut.ut_pid = getpid ();
#if _HAVE_UT_TYPE - 0
- ut.ut_type = USER_PROCESS;
+ ut.ut_type = name[0] ? USER_PROCESS : DEAD_PROCESS;
#endif
strncpy (ut.ut_line, line, sizeof ut.ut_line);
strncpy (ut.ut_name, name, sizeof ut.ut_name);
@@ -52,14 +50,36 @@ logwtmp (const char *line, const char *name, const char *host)
#endif
#if _HAVE_UT_TV - 0
- gettimeofday (&ut.ut_tv, NULL);
+ __gettimeofday (&ut.ut_tv, NULL);
#else
- time (&ut.ut_time);
+ __time (&ut.ut_time);
#endif
- /* Write the entry. */
- pututline_r (&ut, &data);
+ /* Try to lock the file. */
+ if (__flock (fd, LOCK_EX | LOCK_NB) < 0 && errno != ENOSYS)
+ {
+ /* Oh, oh. The file is already locked. Wait a bit and try again. */
+ sleep (1);
+
+ /* This time we ignore the error. */
+ __flock (fd, LOCK_EX | LOCK_NB);
+ }
+
+ /* Remeber original size of log file: */
+ if (__fstat (fd, &st) < 0)
+ goto done;
+
+ /* Write the entry. If we can't write all the bytes, reset the file
+ size back to the original size. That way, no partial entries
+ will remain. */
+ written = __write (fd, &ut, sizeof (ut));
+ if (written > 0 && written != sizeof (ut))
+ ftruncate (fd, st.st_size);
+
+done:
+ /* And unlock the file. */
+ __flock (fd, LOCK_UN);
- /* Close UTMP file. */
- endutent_r (&data);
+ /* Close WTMP file. */
+ __close (fd);
}