coreutils fixes + cleanups for who, uptime, users, pinky

[Paul Eggert]

I installed the following cleanups to fix various bugs where "who" and
related programs messed up if the number of users exceeds INT_MAX or
if it causes size calculations to overflow (which can occur with a
fewer number of users; it depends on the platform), or if the clock
has gone bad and the number of idle days "exceeds" 10**8 or
INT_MAX/86400.

2004-08-02  Paul Eggert  <address@hidden>

        * lib/readutmp.h (UT_USER): Parenthesize properly.
        (UT_USER_SIZE): New constant.
        (read_utmp): Don't assume that the number of users is less than
        INT_MAX.
        * lib/readutmp.c (read_utmp): Likewise.
        Check for integer overflow in size calculations.
        Return -1 (not 1) on failure, since we set errno in that case.

        * src/pinky.c (include_idle, include_heading, include_fullname,
        include_project, include_plan, include_home_and_shell, do_short_format,
        include_where, main): Use bool for booleans.
        (count_ampersands, create_fullname, scan_entries, short_pinky):
        Use size_t for sizes.
        (create_fullname): Check for overflow in size calculations.
        (idle_string): Don't assume that the number of idle days
        is less than 10**8 and/or INT_MAX/(24*60*60).
        (main): No need to pass a non-NULL last arg to getopt_long.
        * src/uptime.c (print_uptime, uptime): Use size_t for sizes.
        (print_uptime): Remove unused local variable.
        (main): No need to pass a non-NULL last arg to getopt_long.
        * src/users.c (list_entries_users, users): Use size_t for sizes.
        (list_entries_users): Use char for bytes.
        (main): No need to pass a non-NULL last arg to getopt_long.
        * src/who.c (do_lookup, short_list, short_output, include_idle,
        include_heading, include_mesg, include_exit, need_boottime,
        need_deadprocs, need_login, need_initspawn, need_clockchange,
        need_runlevel, need_users, my_line_only, main): Use bool for booleans.
        (print_runlevel): Use unsigned char for bytes.
        (list_entries_who, scan_entries, who): Use size_t for sizes.
        (main): No need to pass a non-NULL last arg to getopt_long.

Index: lib/readutmp.h
===================================================================
RCS file: /home/eggert/coreutils/cu/lib/readutmp.h,v
retrieving revision 1.15
diff -p -u -r1.15 readutmp.h
--- lib/readutmp.h      18 Aug 2003 09:44:49 -0000      1.15
+++ lib/readutmp.h      18 Jul 2004 05:48:03 -0000
@@ -116,11 +116,11 @@
 # else
 
 #  if HAVE_STRUCT_UTMP_UT_USER
-#   define UT_USER(Utmp) Utmp->ut_user
+#   define UT_USER(Utmp) ((Utmp)->ut_user)
 #  endif
 #  if HAVE_STRUCT_UTMP_UT_NAME
 #   undef UT_USER
-#   define UT_USER(Utmp) Utmp->ut_name
+#   define UT_USER(Utmp) ((Utmp)->ut_name)
 #  endif
 
 # endif
@@ -143,6 +143,8 @@
 
 typedef struct UTMP_STRUCT_NAME STRUCT_UTMP;
 
+enum { UT_USER_SIZE = sizeof UT_USER ((STRUCT_UTMP *) 0) };
+
 # include <time.h>
 # ifdef HAVE_SYS_PARAM_H
 #  include <sys/param.h>
@@ -180,6 +182,6 @@ extern int errno;
 # endif
 
 char *extract_trimmed_name (const STRUCT_UTMP *ut);
-int read_utmp (const char *filename, int *n_entries, STRUCT_UTMP **utmp_buf);
+int read_utmp (const char *filename, size_t *n_entries, STRUCT_UTMP 
**utmp_buf);
 
 #endif /* __READUTMP_H__ */
Index: lib/readutmp.c
===================================================================
RCS file: /home/eggert/coreutils/cu/lib/readutmp.c,v
retrieving revision 1.20
diff -p -u -r1.20 readutmp.c
--- lib/readutmp.c      12 Jun 2004 08:07:30 -0000      1.20
+++ lib/readutmp.c      17 Jul 2004 03:44:36 -0000
@@ -54,16 +54,17 @@ extract_trimmed_name (const STRUCT_UTMP 
 /* Read the utmp entries corresponding to file FILENAME into freshly-
    malloc'd storage, set *UTMP_BUF to that pointer, set *N_ENTRIES to
    the number of entries, and return zero.  If there is any error,
-   return non-zero and don't modify the parameters.  */
+   return -1, setting errno, and don't modify the parameters.  */
 
 #ifdef UTMP_NAME_FUNCTION
 
 int
-read_utmp (const char *filename, int *n_entries, STRUCT_UTMP **utmp_buf)
+read_utmp (const char *filename, size_t *n_entries, STRUCT_UTMP **utmp_buf)
 {
-  int n_read;
+  size_t n_read;
+  size_t n_alloc = 4;
+  STRUCT_UTMP *utmp = xmalloc (n_alloc * sizeof *utmp);
   STRUCT_UTMP *u;
-  STRUCT_UTMP *utmp = NULL;
 
   /* Ignore the return value for now.
      Solaris' utmpname returns 1 upon success -- which is contrary
@@ -76,16 +77,12 @@ read_utmp (const char *filename, int *n_
   n_read = 0;
   while ((u = GET_UTMP_ENT ()) != NULL)
     {
-      STRUCT_UTMP *p;
-      ++n_read;
-      p = (STRUCT_UTMP *) realloc (utmp, n_read * sizeof (STRUCT_UTMP));
-      if (p == NULL)
+      if (n_read == n_alloc)
        {
-         free (utmp);
-         END_UTMP_ENT ();
-         return 1;
+         utmp = xnrealloc (utmp, n_alloc, 2 * sizeof *utmp);
+         n_alloc *= 2;
        }
-      utmp = p;
+      ++n_read;
       utmp[n_read - 1] = *u;
     }
 
@@ -100,7 +97,7 @@ read_utmp (const char *filename, int *n_
 #else
 
 int
-read_utmp (const char *filename, int *n_entries, STRUCT_UTMP **utmp_buf)
+read_utmp (const char *filename, size_t *n_entries, STRUCT_UTMP **utmp_buf)
 {
   FILE *utmp;
   struct stat file_stats;
@@ -110,14 +107,14 @@ read_utmp (const char *filename, int *n_
 
   utmp = fopen (filename, "r");
   if (utmp == NULL)
-    return 1;
+    return -1;
 
   if (fstat (fileno (utmp), &file_stats) != 0)
     {
       int e = errno;
       fclose (utmp);
       errno = e;
-      return 1;
+      return -1;
     }
   size = file_stats.st_size;
   buf = xmalloc (size);
@@ -128,14 +125,14 @@ read_utmp (const char *filename, int *n_
       free (buf);
       fclose (utmp);
       errno = e;
-      return 1;
+      return -1;
     }
   if (fclose (utmp) != 0)
     {
       int e = errno;
       free (buf);
       errno = e;
-      return 1;
+      return -1;
     }
 
   *n_entries = n_read;
Index: src/pinky.c
===================================================================
RCS file: /home/eggert/coreutils/cu/src/pinky.c,v
retrieving revision 1.40
diff -p -u -r1.40 pinky.c
--- src/pinky.c 22 Jun 2004 15:00:53 -0000      1.40
+++ src/pinky.c 20 Jul 2004 05:36:32 -0000
@@ -49,33 +49,33 @@ char *ttyname ();
 /* The name this program was run with. */
 const char *program_name;
 
-/* If nonzero, display the hours:minutes since each user has touched
+/* If true, display the hours:minutes since each user has touched
    the keyboard, or blank if within the last minute, or days followed
    by a 'd' if not within the last day. */
-static int include_idle = 1;
+static bool include_idle = true;
 
-/* If nonzero, display a line at the top describing each field. */
-static int include_heading = 1;
+/* If true, display a line at the top describing each field. */
+static bool include_heading = true;
 
-/* if nonzero, display the user's full name from pw_gecos. */
-static int include_fullname = 1;
+/* if true, display the user's full name from pw_gecos. */
+static bool include_fullname = true;
 
-/* if nonzero, display the user's ~/.project file when doing long format. */
-static int include_project = 1;
+/* if true, display the user's ~/.project file when doing long format. */
+static bool include_project = true;
 
-/* if nonzero, display the user's ~/.plan file when doing long format. */
-static int include_plan = 1;
+/* if true, display the user's ~/.plan file when doing long format. */
+static bool include_plan = true;
 
-/* if nonzero, display the user's home directory and shell
+/* if true, display the user's home directory and shell
    when doing long format. */
-static int include_home_and_shell = 1;
+static bool include_home_and_shell = true;
 
-/* if nonzero, use the "short" output format. */
-static int do_short_format = 1;
+/* if true, use the "short" output format. */
+static bool do_short_format = true;
 
-/* if nonzero, display the ut_host field. */
+/* if true, display the ut_host field. */
 #ifdef HAVE_UT_HOST
-static int include_where = 1;
+static bool include_where = true;
 #endif
 
 /* The strftime format to use for login times, and its expected
@@ -92,10 +92,10 @@ static struct option const longopts[] =
 
 /* Count and return the number of ampersands in STR.  */
 
-static int
+static size_t
 count_ampersands (const char *str)
 {
-  int count = 0;
+  size_t count = 0;
   do
     {
       if (*str == '&')
@@ -113,10 +113,21 @@ count_ampersands (const char *str)
 static char *
 create_fullname (const char *gecos_name, const char *user_name)
 {
-  const int result_len = strlen (gecos_name)
-    + count_ampersands (gecos_name) * (strlen (user_name) - 1) + 1;
-  char *const result = xmalloc (result_len);
-  char *r = result;
+  size_t rsize = strlen (gecos_name) + 1;
+  char *result;
+  char *r;
+  size_t ampersands = count_ampersands (gecos_name);
+
+  if (ampersands != 0)
+    {
+      size_t ulen = strlen (user_name);
+      size_t product = ampersands * ulen;
+      rsize += product - ampersands;
+      if (xalloc_oversized (ulen, ampersands) || rsize < product)
+       xalloc_die ();
+    }
+
+  r = result = xmalloc (rsize);
 
   while (*gecos_name)
     {
@@ -147,7 +158,7 @@ static const char *
 idle_string (time_t when)
 {
   static time_t now = 0;
-  static char idle_hhmm[10];
+  static char buf[INT_STRLEN_BOUND (long int) + 2];
   time_t seconds_idle;
 
   if (now == 0)
@@ -158,13 +169,16 @@ idle_string (time_t when)
     return "     ";
   if (seconds_idle < (24 * 60 * 60))   /* One day. */
     {
-      sprintf (idle_hhmm, "%02d:%02d",
-              (int) (seconds_idle / (60 * 60)),
-              (int) ((seconds_idle % (60 * 60)) / 60));
-      return (const char *) idle_hhmm;
+      int hours = seconds_idle / (60 * 60);
+      int minutes = (seconds_idle % (60 * 60)) / 60;
+      sprintf (buf, "%02d:%02d", hours, minutes);
     }
-  sprintf (idle_hhmm, "%dd", (int) (seconds_idle / (24 * 60 * 60)));
-  return (const char *) idle_hhmm;
+  else
+    {
+      unsigned long int days = seconds_idle / (24 * 60 * 60);
+      sprintf (buf, "%lud", days);
+    }
+  return buf;
 }
 
 /* Return a time string.  */
@@ -231,15 +245,15 @@ print_entry (const STRUCT_UTMP *utmp_ent
       last_change = 0;
     }
 
-  printf ("%-8.*s", (int) sizeof (UT_USER (utmp_ent)), UT_USER (utmp_ent));
+  printf ("%-8.*s", UT_USER_SIZE, UT_USER (utmp_ent));
 
   if (include_fullname)
     {
       struct passwd *pw;
-      char name[sizeof (UT_USER (utmp_ent)) + 1];
+      char name[UT_USER_SIZE + 1];
 
-      strncpy (name, UT_USER (utmp_ent), sizeof (UT_USER (utmp_ent)));
-      name[sizeof (UT_USER (utmp_ent))] = '\0';
+      strncpy (name, UT_USER (utmp_ent), UT_USER_SIZE);
+      name[UT_USER_SIZE] = '\0';
       pw = getpwnam (name);
       if (pw == NULL)
        printf (" %19s", "        ???");
@@ -422,7 +436,7 @@ print_heading (void)
 /* Display UTMP_BUF, which should have N entries. */
 
 static void
-scan_entries (int n, const STRUCT_UTMP *utmp_buf,
+scan_entries (size_t n, const STRUCT_UTMP *utmp_buf,
              const int argc_names, char *const argv_names[])
 {
   if (hard_locale (LC_TIME))
@@ -452,8 +466,8 @@ scan_entries (int n, const STRUCT_UTMP *
              int i;
 
              for (i = 0; i < argc_names; i++)
-               if (strncmp (UT_USER (utmp_buf), argv_names[i],
-                            sizeof (UT_USER (utmp_buf))) == 0)
+               if (strncmp (UT_USER (utmp_buf), argv_names[i], UT_USER_SIZE)
+                   == 0)
                  {
                    print_entry (utmp_buf);
                    break;
@@ -472,11 +486,10 @@ static void
 short_pinky (const char *filename,
             const int argc_names, char *const argv_names[])
 {
-  int n_users;
+  size_t n_users;
   STRUCT_UTMP *utmp_buf;
-  int fail = read_utmp (filename, &n_users, &utmp_buf);
 
-  if (fail)
+  if (read_utmp (filename, &n_users, &utmp_buf) != 0)
     error (EXIT_FAILURE, errno, "%s", filename);
 
   scan_entries (n_users, utmp_buf, argc_names, argv_names);
@@ -530,7 +543,7 @@ The utmp file will be %s.\n\
 int
 main (int argc, char **argv)
 {
-  int optc, longind;
+  int optc;
   int n_users;
 
   initialize_main (&argc, &argv);
@@ -541,8 +554,7 @@ main (int argc, char **argv)
 
   atexit (close_stdout);
 
-  while ((optc = getopt_long (argc, argv, "sfwiqbhlp", longopts, &longind))
-        != -1)
+  while ((optc = getopt_long (argc, argv, "sfwiqbhlp", longopts, NULL)) != -1)
     {
       switch (optc)
        {
@@ -550,46 +562,46 @@ main (int argc, char **argv)
          break;
 
        case 's':
-         do_short_format = 1;
+         do_short_format = true;
          break;
 
        case 'l':
-         do_short_format = 0;
+         do_short_format = false;
          break;
 
        case 'f':
-         include_heading = 0;
+         include_heading = false;
          break;
 
        case 'w':
-         include_fullname = 0;
+         include_fullname = false;
          break;
 
        case 'i':
-         include_fullname = 0;
+         include_fullname = false;
 #ifdef HAVE_UT_HOST
-         include_where = 0;
+         include_where = false;
 #endif
          break;
 
        case 'q':
-         include_fullname = 0;
+         include_fullname = false;
 #ifdef HAVE_UT_HOST
-         include_where = 0;
+         include_where = false;
 #endif
-         include_idle = 0;
+         include_idle = false;
          break;
 
        case 'h':
-         include_project = 0;
+         include_project = false;
          break;
 
        case 'p':
-         include_plan = 0;
+         include_plan = false;
          break;
 
        case 'b':
-         include_home_and_shell = 0;
+         include_home_and_shell = false;
          break;
 
        case_GETOPT_HELP_CHAR;
@@ -603,7 +615,7 @@ main (int argc, char **argv)
 
   n_users = argc - optind;
 
-  if (do_short_format == 0 && n_users == 0)
+  if (!do_short_format && n_users == 0)
     {
       error (0, 0, _("no username specified; at least one must be\
  specified when using -l"));
Index: src/uptime.c
===================================================================
RCS file: /home/eggert/coreutils/cu/src/uptime.c,v
retrieving revision 1.43
diff -p -u -r1.43 uptime.c
--- src/uptime.c        24 Jul 2004 08:03:02 -0000      1.43
+++ src/uptime.c        24 Jul 2004 18:44:44 -0000
@@ -50,9 +50,9 @@ static struct option const longopts[] =
 };
 
 static void
-print_uptime (int n, const STRUCT_UTMP *this)
+print_uptime (size_t n, const STRUCT_UTMP *this)
 {
-  register int entries = 0;
+  size_t entries = 0;
   time_t boot_time = 0;
   time_t time_now;
   time_t uptime = 0;
@@ -70,7 +70,6 @@ print_uptime (int n, const STRUCT_UTMP *
   if (fp != NULL)
     {
       char buf[BUFSIZ];
-      int res;
       char *b = fgets (buf, BUFSIZ, fp);
       if (b == buf)
        {
@@ -149,7 +148,8 @@ print_uptime (int n, const STRUCT_UTMP *
        printf (ngettext ("%ld day", "%ld days", updays), updays);
       printf (" %2d:%02d,  ", uphours, upmins);
     }
-  printf (ngettext ("%d user", "%d users", entries), entries);
+  printf (ngettext ("%lu user", "%lu users", entries),
+         (unsigned long int) entries);
 
 #if defined (HAVE_GETLOADAVG) || defined (C_GETLOADAVG)
   loads = getloadavg (avg, 3);
@@ -178,11 +178,10 @@ print_uptime (int n, const STRUCT_UTMP *
 static void
 uptime (const char *filename)
 {
-  int n_users;
+  size_t n_users;
   STRUCT_UTMP *utmp_buf;
-  int fail = read_utmp (filename, &n_users, &utmp_buf);
 
-  if (fail)
+  if (read_utmp (filename, &n_users, &utmp_buf) != 0)
     error (EXIT_FAILURE, errno, "%s", filename);
 
   print_uptime (n_users, utmp_buf);
@@ -215,7 +214,7 @@ If FILE is not specified, use %s.  %s as
 int
 main (int argc, char **argv)
 {
-  int optc, longind;
+  int optc;
   initialize_main (&argc, &argv);
   program_name = argv[0];
   setlocale (LC_ALL, "");
@@ -227,7 +226,7 @@ main (int argc, char **argv)
   parse_long_options (argc, argv, PROGRAM_NAME, GNU_PACKAGE, VERSION,
                      usage, AUTHORS, (char const *) NULL);
 
-  while ((optc = getopt_long (argc, argv, "", longopts, &longind)) != -1)
+  while ((optc = getopt_long (argc, argv, "", longopts, NULL)) != -1)
     {
       switch (optc)
        {
Index: src/users.c
===================================================================
RCS file: /home/eggert/coreutils/cu/src/users.c,v
retrieving revision 1.35
diff -p -u -r1.35 users.c
--- src/users.c 21 Jun 2004 15:03:35 -0000      1.35
+++ src/users.c 19 Jul 2004 23:52:54 -0000
@@ -51,15 +51,13 @@ userid_compare (const void *v_a, const v
 }
 
 static void
-list_entries_users (int n, const STRUCT_UTMP *this)
+list_entries_users (size_t n, const STRUCT_UTMP *this)
 {
-  char **u;
-  int i;
-  int n_entries;
-
-  n_entries = 0;
-  u = xnmalloc (n, sizeof *u);
-  for (i = 0; i < n; i++)
+  char **u = xnmalloc (n, sizeof *u);
+  size_t i;
+  size_t n_entries = 0;
+
+  while (n--)
     {
       if (UT_USER (this) [0]
 #ifdef USER_PROCESS
@@ -81,9 +79,8 @@ list_entries_users (int n, const STRUCT_
 
   for (i = 0; i < n_entries; i++)
     {
-      int c;
+      char c = (i < n_entries - 1 ? ' ' : '\n');
       fputs (u[i], stdout);
-      c = (i < n_entries - 1 ? ' ' : '\n');
       putchar (c);
     }
 
@@ -97,11 +94,10 @@ list_entries_users (int n, const STRUCT_
 static void
 users (const char *filename)
 {
-  int n_users;
+  size_t n_users;
   STRUCT_UTMP *utmp_buf;
-  int fail = read_utmp (filename, &n_users, &utmp_buf);
 
-  if (fail)
+  if (read_utmp (filename, &n_users, &utmp_buf) != 0)
     error (EXIT_FAILURE, errno, "%s", filename);
 
   list_entries_users (n_users, utmp_buf);
@@ -134,7 +130,7 @@ If FILE is not specified, use %s.  %s as
 int
 main (int argc, char **argv)
 {
-  int optc, longind;
+  int optc;
   initialize_main (&argc, &argv);
   program_name = argv[0];
   setlocale (LC_ALL, "");
@@ -146,7 +142,7 @@ main (int argc, char **argv)
   parse_long_options (argc, argv, PROGRAM_NAME, GNU_PACKAGE, VERSION,
                      usage, AUTHORS, (char const *) NULL);
 
-  while ((optc = getopt_long (argc, argv, "", longopts, &longind)) != -1)
+  while ((optc = getopt_long (argc, argv, "", longopts, NULL)) != -1)
     {
       switch (optc)
        {
Index: src/who.c
===================================================================
RCS file: /home/eggert/coreutils/cu/src/who.c,v
retrieving revision 1.100
diff -p -u -r1.100 who.c
--- src/who.c   24 Jul 2004 08:01:49 -0000      1.100
+++ src/who.c   25 Jul 2004 04:53:16 -0000
@@ -119,55 +119,55 @@ char *canon_host ();
 /* The name this program was run with. */
 char *program_name;
 
-/* If nonzero, attempt to canonicalize hostnames via a DNS lookup. */
-static int do_lookup;
+/* If true, attempt to canonicalize hostnames via a DNS lookup. */
+static bool do_lookup;
 
-/* If nonzero, display only a list of usernames and count of
+/* If true, display only a list of usernames and count of
    the users logged on.
-   Ignored for `who am i'. */
-static int short_list;
+   Ignored for `who am i'.  */
+static bool short_list;
 
-/* If nonzero, display only name, line, and time fields */
-static int short_output;
+/* If true, display only name, line, and time fields.  */
+static bool short_output;
 
-/* If nonzero, display the hours:minutes since each user has touched
+/* If true, display the hours:minutes since each user has touched
    the keyboard, or "." if within the last minute, or "old" if
-   not within the last day. */
-static int include_idle;
+   not within the last day.  */
+static bool include_idle;
 
-/* If nonzero, display a line at the top describing each field. */
-static int include_heading;
+/* If true, display a line at the top describing each field.  */
+static bool include_heading;
 
-/* If nonzero, display a `+' for each user if mesg y, a `-' if mesg n,
+/* If true, display a `+' for each user if mesg y, a `-' if mesg n,
    or a `?' if their tty cannot be statted. */
-static int include_mesg;
+static bool include_mesg;
 
-/* If nonzero, display process termination & exit status */
-static int include_exit;
+/* If true, display process termination & exit status.  */
+static bool include_exit;
 
-/* If nonzero, display the last boot time */
-static int need_boottime;
+/* If true, display the last boot time.  */
+static bool need_boottime;
 
-/* If nonzero, display dead processes */
-static int need_deadprocs;
+/* If true, display dead processes.  */
+static bool need_deadprocs;
 
-/* If nonzero, display processes waiting for user login */
-static int need_login;
+/* If true, display processes waiting for user login.  */
+static bool need_login;
 
-/* If nonzero, display processes started by init */
-static int need_initspawn;
+/* If true, display processes started by init.  */
+static bool need_initspawn;
 
-/* If nonzero, display the last clock change */
-static int need_clockchange;
+/* If true, display the last clock change.  */
+static bool need_clockchange;
 
-/* If nonzero, display the current runlevel */
-static int need_runlevel;
+/* If true, display the current runlevel.  */
+static bool need_runlevel;
 
-/* If nonzero, display user processes */
-static int need_users;
+/* If true, display user processes.  */
+static bool need_users;
 
-/* If nonzero, display info only for the controlling tty */
-static int my_line_only;
+/* If true, display info only for the controlling tty.  */
+static bool my_line_only;
 
 /* The strftime format to use for login times, and its expected
    output width.  */
@@ -515,8 +515,8 @@ static void
 print_runlevel (const STRUCT_UTMP *utmp_ent)
 {
   static char *runlevline, *comment;
-  int last = UT_PID (utmp_ent) / 256;
-  int curr = UT_PID (utmp_ent) % 256;
+  unsigned char last = UT_PID (utmp_ent) / 256;
+  unsigned char curr = UT_PID (utmp_ent) % 256;
 
   if (!runlevline)
     runlevline = xmalloc (strlen (_("run-level")) + 3);
@@ -535,9 +535,9 @@ print_runlevel (const STRUCT_UTMP *utmp_
 /* Print the username of each valid entry and the number of valid entries
    in UTMP_BUF, which should have N elements. */
 static void
-list_entries_who (int n, const STRUCT_UTMP *utmp_buf)
+list_entries_who (size_t n, const STRUCT_UTMP *utmp_buf)
 {
-  int entries = 0;
+  unsigned long int entries = 0;
   char const *separator = "";
 
   while (n--)
@@ -555,7 +555,7 @@ list_entries_who (int n, const STRUCT_UT
        }
       utmp_buf++;
     }
-  printf (_("\n# users=%u\n"), entries);
+  printf (_("\n# users=%lu\n"), entries);
 }
 
 static void
@@ -567,7 +567,7 @@ print_heading (void)
 
 /* Display UTMP_BUF, which should have N entries. */
 static void
-scan_entries (int n, const STRUCT_UTMP *utmp_buf)
+scan_entries (size_t n, const STRUCT_UTMP *utmp_buf)
 {
   char *ttyname_b IF_LINT ( = NULL);
   time_t boottime = TYPE_MINIMUM (time_t);
@@ -620,11 +620,10 @@ scan_entries (int n, const STRUCT_UTMP *
 static void
 who (const char *filename)
 {
-  int n_users;
+  size_t n_users;
   STRUCT_UTMP *utmp_buf;
-  int fail = read_utmp (filename, &n_users, &utmp_buf);
 
-  if (fail)
+  if (read_utmp (filename, &n_users, &utmp_buf) != 0)
     error (EXIT_FAILURE, errno, "%s", filename);
 
   if (short_list)
@@ -688,8 +687,8 @@ If ARG1 ARG2 given, -m presumed: `am i' 
 int
 main (int argc, char **argv)
 {
-  int optc, longind;
-  int assumptions = 1;
+  int optc;
+  bool assumptions = true;
 
   initialize_main (&argc, &argv);
   program_name = argv[0];
@@ -699,8 +698,8 @@ main (int argc, char **argv)
 
   atexit (close_stdout);
 
-  while ((optc = getopt_long (argc, argv, "abdilmpqrstuwHT", longopts,
-                             &longind)) != -1)
+  while ((optc = getopt_long (argc, argv, "abdilmpqrstuwHT", longopts, NULL))
+        != -1)
     {
       switch (optc)
        {
@@ -708,72 +707,72 @@ main (int argc, char **argv)
          break;
 
        case 'a':
-         need_boottime = 1;
-         need_deadprocs = 1;
-         need_login = 1;
-         need_initspawn = 1;
-         need_runlevel = 1;
-         need_clockchange = 1;
-         need_users = 1;
-         include_mesg = 1;
-         include_idle = 1;
-         include_exit = 1;
-         assumptions = 0;
+         need_boottime = true;
+         need_deadprocs = true;
+         need_login = true;
+         need_initspawn = true;
+         need_runlevel = true;
+         need_clockchange = true;
+         need_users = true;
+         include_mesg = true;
+         include_idle = true;
+         include_exit = true;
+         assumptions = false;
          break;
 
        case 'b':
-         need_boottime = 1;
-         assumptions = 0;
+         need_boottime = true;
+         assumptions = false;
          break;
 
        case 'd':
-         need_deadprocs = 1;
-         include_idle = 1;
-         include_exit = 1;
-         assumptions = 0;
+         need_deadprocs = true;
+         include_idle = true;
+         include_exit = true;
+         assumptions = false;
          break;
 
        case 'H':
-         include_heading = 1;
+         include_heading = true;
          break;
 
        case 'l':
-         need_login = 1;
-         include_idle = 1;
-         assumptions = 0;
+         need_login = true;
+         include_idle = true;
+         assumptions = false;
          break;
 
        case 'm':
-         my_line_only = 1;
+         my_line_only = true;
          break;
 
        case 'p':
-         need_initspawn = 1;
-         assumptions = 0;
+         need_initspawn = true;
+         assumptions = false;
          break;
 
        case 'q':
-         short_list = 1;
+         short_list = true;
          break;
 
        case 'r':
-         need_runlevel = 1;
-         include_idle = 1;
-         assumptions = 0;
+         need_runlevel = true;
+         include_idle = true;
+         assumptions = false;
          break;
 
        case 's':
-         short_output = 1;
+         short_output = true;
          break;
 
        case 't':
-         need_clockchange = 1;
-         assumptions = 0;
+         need_clockchange = true;
+         assumptions = false;
          break;
 
        case 'T':
        case 'w':
-         include_mesg = 1;
+         include_mesg = true;
          break;
 
        case 'i':
@@ -782,13 +781,13 @@ main (int argc, char **argv)
   use -u instead"));
          /* Fall through.  */
        case 'u':
-         need_users = 1;
-         include_idle = 1;
-         assumptions = 0;
+         need_users = true;
+         include_idle = true;
+         assumptions = false;
          break;
 
        case LOOKUP_OPTION:
-         do_lookup = 1;
+         do_lookup = true;
          break;
 
          case_GETOPT_HELP_CHAR;
@@ -802,13 +801,13 @@ main (int argc, char **argv)
 
   if (assumptions)
     {
-      need_users = 1;
-      short_output = 1;
+      need_users = true;
+      short_output = true;
     }
 
   if (include_exit)
     {
-      short_output = 0;
+      short_output = false;
     }
 
   if (hard_locale (LC_TIME))
@@ -834,7 +833,7 @@ main (int argc, char **argv)
       break;
 
     case 2:                    /* who <blurf> <glop> */
-      my_line_only = 1;
+      my_line_only = true;
       who (UTMP_FILE);
       break;