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-rw-r--r--login/utmp_file.c179
1 files changed, 89 insertions, 90 deletions
diff --git a/login/utmp_file.c b/login/utmp_file.c
index 6d6e05b..bea6364 100644
--- a/login/utmp_file.c
+++ b/login/utmp_file.c
@@ -18,13 +18,11 @@
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
+#include <assert.h>
#include <errno.h>
#include <fcntl.h>
-#include <limits.h>
#include <stdio.h>
-#include <stdlib.h>
#include <string.h>
-#include <sys/stat.h>
#include <unistd.h>
#include <utmp.h>
@@ -32,9 +30,10 @@
/* Descriptor for the file and position. */
-static int file_fd = INT_MIN;
+static int file_fd = -1;
static off_t file_offset;
+/* Cache for the last read entry. */
static struct utmp last_entry;
@@ -68,14 +67,14 @@ setutent_file (void)
if (file_fd < 0)
{
const char *file_name = __libc_utmp_file_name;
-
+
if (strcmp (__libc_utmp_file_name, _PATH_UTMP) == 0
&& __access (_PATH_UTMP "x", F_OK) == 0)
file_name = _PATH_UTMP "x";
else if (strcmp (__libc_utmp_file_name, _PATH_WTMP) == 0
&& __access (_PATH_WTMP "x", F_OK) == 0)
file_name = _PATH_WTMP "x";
-
+
file_fd = open (file_name, O_RDWR);
if (file_fd == -1)
{
@@ -96,18 +95,8 @@ setutent_file (void)
/* Make sure the entry won't match. */
last_entry.ut_type = -1;
#endif
-
- return 1;
-}
-
-
-static void
-endutent_file (void)
-{
- if (file_fd >= 0)
- close (file_fd);
- file_fd = INT_MIN;
+ return 1;
}
@@ -117,11 +106,9 @@ getutent_r_file (struct utmp *buffer, struct utmp **result)
ssize_t nbytes;
struct flock fl; /* Information struct for locking. */
- /* Open utmp file if not already done. */
- if (file_fd == INT_MIN)
- setutent_file ();
+ assert (file_fd >= 0);
- if (file_fd == -1 || file_offset == -1l)
+ if (file_offset == -1l)
{
/* Not available. */
*result = NULL;
@@ -131,12 +118,16 @@ getutent_r_file (struct utmp *buffer, struct utmp **result)
/* XXX The following is not perfect. Instead of locking the file itself
Marek Michalkiewicz <marekm@i17linuxb.ists.pwr.wroc.pl> suggests to
use an extra locking file. */
+ /* XXX I think using an extra locking file does not solve the
+ problems. Instead we should set an alarm, which causes fcntl to
+ fail, as in ../nis/lckcache.c.
+ Mark Kettenis <kettenis@phys.uva.nl>. */
/* Try to get the lock. */
memset (&fl, '\0', sizeof (struct flock));
fl.l_type = F_RDLCK;
fl.l_whence = SEEK_SET;
- fcntl (file_fd, F_SETLKW, &fl);
+ fcntl (file_fd, F_SETLK, &fl);
/* Read the next entry. */
nbytes = read (file_fd, &last_entry, sizeof (struct utmp));
@@ -162,62 +153,6 @@ getutent_r_file (struct utmp *buffer, struct utmp **result)
}
-/* For implementing this function we don't use the getutent_r function
- because we can avoid the reposition on every new entry this way. */
-static int
-getutline_r_file (const struct utmp *line, struct utmp *buffer,
- struct utmp **result)
-{
- struct flock fl;
-
- if (file_fd < 0 || file_offset == -1l)
- {
- *result = NULL;
- return -1;
- }
-
- /* Try to get the lock. */
- memset (&fl, '\0', sizeof (struct flock));
- fl.l_type = F_RDLCK;
- fl.l_whence = SEEK_SET;
- fcntl (file_fd, F_SETLKW, &fl);
-
- while (1)
- {
- /* Read the next entry. */
- if (read (file_fd, &last_entry, sizeof (struct utmp))
- != sizeof (struct utmp))
- {
- __set_errno (ESRCH);
- file_offset = -1l;
- *result = NULL;
- goto unlock_return;
- }
- file_offset += sizeof (struct utmp);
-
- /* Stop if we found a user or login entry. */
- if (
-#if _HAVE_UT_TYPE - 0
- (last_entry.ut_type == USER_PROCESS
- || last_entry.ut_type == LOGIN_PROCESS)
- &&
-#endif
- !strncmp (line->ut_line, last_entry.ut_line, sizeof line->ut_line))
- break;
- }
-
- memcpy (buffer, &last_entry, sizeof (struct utmp));
- *result = buffer;
-
-unlock_return:
- /* And unlock the file. */
- fl.l_type = F_UNLCK;
- fcntl (file_fd, F_SETLKW, &fl);
-
- return ((*result == NULL) ? -1 : 0);
-}
-
-
static int
proc_utmp_eq (const struct utmp *entry, const struct utmp *match)
{
@@ -308,7 +243,7 @@ internal_getut_r (const struct utmp *id, struct utmp *buffer)
unlock_return:
/* And unlock the file. */
fl.l_type = F_UNLCK;
- fcntl (file_fd, F_SETLKW, &fl);
+ fcntl (file_fd, F_SETLK, &fl);
return result;
}
@@ -320,7 +255,9 @@ static int
getutid_r_file (const struct utmp *id, struct utmp *buffer,
struct utmp **result)
{
- if (file_fd < 0 || file_offset == -1l)
+ assert (file_fd >= 0);
+
+ if (file_offset == -1l)
{
*result = NULL;
return -1;
@@ -339,6 +276,64 @@ getutid_r_file (const struct utmp *id, struct utmp *buffer,
}
+/* For implementing this function we don't use the getutent_r function
+ because we can avoid the reposition on every new entry this way. */
+static int
+getutline_r_file (const struct utmp *line, struct utmp *buffer,
+ struct utmp **result)
+{
+ struct flock fl;
+
+ assert (file_fd >= 0);
+
+ if (file_offset == -1l)
+ {
+ *result = NULL;
+ return -1;
+ }
+
+ /* Try to get the lock. */
+ memset (&fl, '\0', sizeof (struct flock));
+ fl.l_type = F_RDLCK;
+ fl.l_whence = SEEK_SET;
+ fcntl (file_fd, F_SETLKW, &fl);
+
+ while (1)
+ {
+ /* Read the next entry. */
+ if (read (file_fd, &last_entry, sizeof (struct utmp))
+ != sizeof (struct utmp))
+ {
+ __set_errno (ESRCH);
+ file_offset = -1l;
+ *result = NULL;
+ goto unlock_return;
+ }
+ file_offset += sizeof (struct utmp);
+
+ /* Stop if we found a user or login entry. */
+ if (
+#if _HAVE_UT_TYPE - 0
+ (last_entry.ut_type == USER_PROCESS
+ || last_entry.ut_type == LOGIN_PROCESS)
+ &&
+#endif
+ !strncmp (line->ut_line, last_entry.ut_line, sizeof line->ut_line))
+ break;
+ }
+
+ memcpy (buffer, &last_entry, sizeof (struct utmp));
+ *result = buffer;
+
+unlock_return:
+ /* And unlock the file. */
+ fl.l_type = F_UNLCK;
+ fcntl (file_fd, F_SETLK, &fl);
+
+ return ((*result == NULL) ? -1 : 0);
+}
+
+
static struct utmp *
pututline_file (const struct utmp *data)
{
@@ -347,13 +342,7 @@ pututline_file (const struct utmp *data)
struct utmp *pbuf;
int found;
- /* Open utmp file if not already done. */
- if (file_fd == INT_MIN)
- setutent_file ();
-
- if (file_fd == -1)
- /* Something went wrong. */
- return NULL;
+ assert (file_fd >= 0);
/* Find the correct place to insert the data. */
if (file_offset > 0
@@ -375,7 +364,7 @@ pututline_file (const struct utmp *data)
memset (&fl, '\0', sizeof (struct flock));
fl.l_type = F_WRLCK;
fl.l_whence = SEEK_SET;
- fcntl (file_fd, F_SETLKW, &fl);
+ fcntl (file_fd, F_SETLK, &fl);
if (found < 0)
{
@@ -418,12 +407,22 @@ pututline_file (const struct utmp *data)
unlock_return:
/* And unlock the file. */
fl.l_type = F_UNLCK;
- fcntl (file_fd, F_SETLKW, &fl);
+ fcntl (file_fd, F_SETLK, &fl);
return pbuf;
}
+static void
+endutent_file (void)
+{
+ assert (file_fd >= 0);
+
+ close (file_fd);
+ file_fd = -1;
+}
+
+
static int
updwtmp_file (const char *file, const struct utmp *utmp)
{
@@ -441,7 +440,7 @@ updwtmp_file (const char *file, const struct utmp *utmp)
memset (&fl, '\0', sizeof (struct flock));
fl.l_type = F_WRLCK;
fl.l_whence = SEEK_SET;
- fcntl (fd, F_SETLKW, &fl);
+ fcntl (fd, F_SETLK, &fl);
/* Remember original size of log file. */
offset = lseek (fd, 0, SEEK_END);
generated by cgit v1.1 at 2024-11-22 19:28:07 +0000