* src/lastlog.c: lastlog variable renamed to ll to avoid name

	clash with the structure.
	* src/lastlog.c: check the offset in print_one() so that it is
	used for the display of one entry or a set of entries.
	* src/lastlog.c: Do not loop over the whole user database when -u
	is used with a single user.
	* src/lastlog.c: Check the size of the lastlog file so that we
	can identify failures to read.

diff --git a/ChangeLog b/ChangeLog
index b8eb40ffc9aadc886028a0c66f699ad1b37ea43f..3680e8c2a40b12c77f2da3fe6c42d9208f75c290 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2009-03-13  Nicolas François  <nicolas.francois@centraliens.net>
+
+       * src/lastlog.c: lastlog variable renamed to ll to avoid name
+       clash with the structure.
+       * src/lastlog.c: check the offset in print_one() so that it is
+       used for the display of one entry or a set of entries.
+       * src/lastlog.c: Do not loop over the whole user database when -u
+       is used with a single user.
+       * src/lastlog.c: Check the size of the lastlog file so that we
+       can identify failures to read.
+
 2009-03-13  Mike Frysinger  <vapier@gentoo.org>
 
        * libmisc/salt.c: Removed l64a prototype. The libc declaration is

diff --git a/src/lastlog.c b/src/lastlog.c
index 97c42648e991043072d4979062116b256b39425b..8f08e87f3dc585c2cb17001f735931ffc28c2420 100644 (file)
--- a/src/lastlog.c
+++ b/src/lastlog.c
@@ -2,7 +2,7 @@
  * Copyright (c) 1989 - 1994, Julianne Frances Haugh
  * Copyright (c) 1996 - 2000, Marek Michałkiewicz
  * Copyright (c) 2000 - 2006, Tomasz Kłoczko
- * Copyright (c) 2007 - 2008, Nicolas François
+ * Copyright (c) 2007 - 2009, Nicolas François
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -41,6 +41,7 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <time.h>
+#include <assert.h>
 #include "defines.h"
 #include "prototypes.h"
 
@@ -55,20 +56,20 @@
  * Global variables
  */
 static FILE *lastlogfile;      /* lastlog file stream */
-static unsigned long umin;     /* if uflg, only display users with uid >= umin */
+static unsigned long umin;     /* if uflg and has_umin, only display users with uid >= umin */
 static bool has_umin = false;
-static unsigned long umax;     /* if uflg, only display users with uid <= umax */
+static unsigned long umax;     /* if uflg and has_umax, only display users with uid <= umax */
 static bool has_umax = false;
 static int days;               /* number of days to consider for print command */
 static time_t seconds;         /* that number of days in seconds */
 static int inverse_days;       /* number of days to consider for print command */
 static time_t inverse_seconds; /* that number of days in seconds */
+static struct stat statbuf;    /* fstat buffer for file size */
 
 
 static bool uflg = false;      /* print only an user of range of users */
 static bool tflg = false;      /* print is restricted to most recent days */
 static bool bflg = false;      /* print excludes most recent days */
-static struct lastlog lastlog; /* scratch structure to play with ... */
 static struct passwd *pwent;
 
 #define        NOW     (time ((time_t *) 0))
@@ -92,6 +93,8 @@ static void print_one (const struct passwd *pw)
        char *cp;
        struct tm *tm;
        time_t ll_time;
+       off_t offset;
+       struct lastlog ll;
 
 #ifdef HAVE_STRFTIME
        char ptime[80];
@@ -101,6 +104,41 @@ static void print_one (const struct passwd *pw)
                return;
        }
 
+
+       offset = pw->pw_uid * sizeof (ll);
+
+       if (offset <= (statbuf.st_size - sizeof (ll))) {
+               /* fseeko errors are not really relevant for us. */
+               assert ( fseeko (lastlogfile, offset, SEEK_SET) == 0 );
+               /* lastlog is a sparse file. Even if no entries were
+                * entered for this user, which should be able to get the
+                * empty entry in this case.
+                */
+               if (fread ((char *) &ll, sizeof (ll), 1, lastlogfile) != 1) {
+                       fprintf (stderr,
+                                _("lastlog: Failed to get the entry for UID %d\n"),
+                                pw->pw_uid);
+                       exit (1);
+               }
+       } else {
+               /* Outsize of the lastlog file.
+                * Behave as if there were a missing entry (same behavior
+                * as if we were reading an non existing entry in the
+                * sparse lastlog file).
+                */
+               memzero (&ll, sizeof (ll));
+       }
+
+       /* Filter out entries that do not match with the -t or -b options */
+       if (tflg && ((NOW - ll.ll_time) > seconds)) {
+               return;
+       }
+
+       if (bflg && ((NOW - ll.ll_time) < inverse_seconds)) {
+               return;
+       }
+
+       /* Print the header only once */
        if (!once) {
 #ifdef HAVE_LL_HOST
                puts (_("Username         Port     From             Latest"));
@@ -109,7 +147,8 @@ static void print_one (const struct passwd *pw)
 #endif
                once = true;
        }
-       ll_time = lastlog.ll_time;
+
+       ll_time = ll.ll_time;
        tm = localtime (&ll_time);
 #ifdef HAVE_STRFTIME
        strftime (ptime, sizeof (ptime), "%a %b %e %H:%M:%S %z %Y", tm);
@@ -119,50 +158,35 @@ static void print_one (const struct passwd *pw)
        cp[24] = '\0';
 #endif
 
-       if (lastlog.ll_time == (time_t) 0) {
+       if (ll.ll_time == (time_t) 0) {
                cp = _("**Never logged in**\0");
        }
 
 #ifdef HAVE_LL_HOST
-       printf ("%-16s %-8.8s %-16.16s %s\n", pw->pw_name,
-               lastlog.ll_line, lastlog.ll_host, cp);
+       printf ("%-16s %-8.8s %-16.16s %s\n",
+               pw->pw_name, ll.ll_line, ll.ll_host, cp);
 #else
-       printf ("%-16s\t%-8.8s %s\n", pw->pw_name, lastlog.ll_line, cp);
+       printf ("%-16s\t%-8.8s %s\n",
+               pw->pw_name, ll.ll_line, cp);
 #endif
 }
 
 static void print (void)
 {
-       off_t offset;
-       uid_t user;
-
-       setpwent ();
-       while ( (pwent = getpwent ()) != NULL ) {
-               user = pwent->pw_uid;
-               if (   uflg
-                   && (   (has_umin && user < (uid_t)umin)
-                       || (has_umax && user > (uid_t)umax))) {
-                       continue;
-               }
-               offset = user * sizeof lastlog;
-
-               fseeko (lastlogfile, offset, SEEK_SET);
-               if (fread ((char *) &lastlog, sizeof lastlog, 1,
-                          lastlogfile) != 1) {
-                       continue;
-               }
-
-               if (tflg && ((NOW - lastlog.ll_time) > seconds)) {
-                       continue;
-               }
-
-               if (bflg && ((NOW - lastlog.ll_time) < inverse_seconds)) {
-                       continue;
+       if (uflg && has_umin && has_umax && (umin == umax)) {
+               print_one (getpwuid ((uid_t)umin));
+       } else {
+               setpwent ();
+               while ( (pwent = getpwent ()) != NULL ) {
+                       if (   uflg
+                           && (   (has_umin && (pwent->pw_uid < (uid_t)umin))
+                               || (has_umax && (pwent->pw_uid > (uid_t)umax)))) {
+                               continue;
+                       }
+                       print_one (pwent);
                }
-
-               print_one (pwent);
+               endpwent ();
        }
-       endpwent ();
 }
 
 int main (int argc, char **argv)
@@ -181,9 +205,8 @@ int main (int argc, char **argv)
                        {NULL, 0, NULL, '\0'}
                };
 
-               while ((c =
-                       getopt_long (argc, argv, "ht:b:u:", longopts,
-                                    NULL)) != -1) {
+               while ((c = getopt_long (argc, argv, "ht:b:u:", longopts,
+                                        NULL)) != -1) {
                        switch (c) {
                        case 'h':
                                usage ();
@@ -207,7 +230,8 @@ int main (int argc, char **argv)
                                 *  - a range (-x, x-, x-y)
                                 */
                                uflg = true;
-                               pwent = xgetpwnam (optarg);
+                               /* local, no need for xgetpwnam */
+                               pwent = getpwnam (optarg);
                                if (NULL != pwent) {
                                        umin = (unsigned long) pwent->pw_uid;
                                        has_umin = true;
@@ -243,6 +267,14 @@ int main (int argc, char **argv)
        }
 
        print ();
+       /* Get the laslog size */
+       if (fstat (fileno (lastlogfile), &statbuf) != 0) {
+               fprintf (stderr,
+                        _("lastlog: Cannot get the size of %s: %s\n"),
+                        LASTLOG_FILE, strerror (errno));
+               exit (1);
+       }
+
        fclose (lastlogfile);
        exit (0);
 }