tweak comment

[gnulib.git] / lib / readutmp.c

diff --git a/lib/readutmp.c b/lib/readutmp.c
index e4caa82..d29163c 100644 (file)
--- a/lib/readutmp.c
+++ b/lib/readutmp.c
@@ -1,5 +1,5 @@
 /* GNU's read utmp module.
-   Copyright (C) 92, 93, 94, 95, 96, 1997 Free Software Foundation, Inc.
+   Copyright (C) 92, 93, 94, 95, 96, 1997, 1998 Free Software Foundation, Inc.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -27,18 +27,14 @@
 #endif /* STDC_HEADERS || HAVE_STRING_H */
 
 #include "readutmp.h"
-#include "error.h"
 
 char *xmalloc ();
 
-STRUCT_UTMP *utmp_contents = 0;
-
 /* Copy UT->ut_name into storage obtained from malloc.  Then remove any
    trailing spaces from the copy, NUL terminate it, and return the copy.  */
 
 char *
-extract_trimmed_name (ut)
-  const STRUCT_UTMP *ut;
+extract_trimmed_name (const STRUCT_UTMP *ut)
 {
   char *p, *trimmed_name;
 
@@ -53,43 +49,109 @@ extract_trimmed_name (ut)
   return trimmed_name;
 }
 
-/* Read the utmp file FILENAME into UTMP_CONTENTS and return the
-   number of entries it contains. */
+/* Read the utmp file FILENAME into *UTMP_BUF, set *N_ENTRIES to the
+   number of entries read, and return zero.  If there is any error,
+   return non-zero and don't modify the parameters.  */
+
+#ifdef HAVE_UTMPNAME
 
 int
-read_utmp (filename)
-  const char *filename;
+read_utmp (const char *filename, int *n_entries, STRUCT_UTMP **utmp_buf)
+{
+  int count_utmp = 0;
+  int n_read;
+  STRUCT_UTMP *u;
+  STRUCT_UTMP *uptr;
+  STRUCT_UTMP *utmp_contents;
+
+  if (utmpname (filename))
+    {
+      return 1;
+    }
+
+  /* FIXME: going through the list twice is wasteful. */
+
+  /* count the entries in utmp */
+  setutent ();
+  while ((u = getutent ()) != NULL)
+    ++count_utmp;
+
+  if (count_utmp == 0)
+    return 0;
+
+  utmp_contents = (STRUCT_UTMP *) xmalloc (count_utmp * sizeof (STRUCT_UTMP));
+
+  /* read the entries in utmp */
+
+  /* FIXME: can this fail? */
+  setutent ();
+
+  n_read = 0;
+  uptr = utmp_contents;
+  while ((u = getutent ()) != NULL)
+    {
+      ++n_read;
+      if (n_read > count_utmp)
+       {
+         STRUCT_UTMP *old_utmp_contents = utmp_contents;
+         ++count_utmp;
+         utmp_contents = (STRUCT_UTMP *) xrealloc (utmp_contents,
+                                                   (count_utmp
+                                                    * sizeof (STRUCT_UTMP)));
+         uptr = utmp_contents + (uptr - old_utmp_contents);
+       }
+      *uptr = *u;
+      ++uptr;
+    }
+
+  if (n_read != count_utmp)
+    utmp_contents = (STRUCT_UTMP *) xrealloc (utmp_contents,
+                                             n_read * sizeof (STRUCT_UTMP));
+
+  /* FIXME: can this fail? */
+  endutent ();
+
+  *n_entries = n_read;
+  *utmp_buf = utmp_contents;
+
+  return 0;
+}
+
+#else
+
+int
+read_utmp (const char *filename, int *n_entries, STRUCT_UTMP **utmp_buf)
 {
   FILE *utmp;
   struct stat file_stats;
   size_t n_read;
   size_t size;
-
-  if (utmp_contents)
-    {
-      free (utmp_contents);
-      utmp_contents = 0;
-    }
+  STRUCT_UTMP *buf;
 
   utmp = fopen (filename, "r");
   if (utmp == NULL)
-    error (1, errno, "%s", filename);
+    return 1;
 
   fstat (fileno (utmp), &file_stats);
   size = file_stats.st_size;
   if (size > 0)
-    utmp_contents = (STRUCT_UTMP *) xmalloc (size);
+    buf = (STRUCT_UTMP *) xmalloc (size);
   else
     {
       fclose (utmp);
-      return 0;
+      return 1;
     }
 
   /* Use < instead of != in case the utmp just grew.  */
-  n_read = fread (utmp_contents, 1, size, utmp);
+  n_read = fread (buf, 1, size, utmp);
   if (ferror (utmp) || fclose (utmp) == EOF
       || n_read < size)
-    error (1, errno, "%s", filename);
+    return 1;
+
+  *n_entries = size / sizeof (STRUCT_UTMP);
+  *utmp_buf = buf;
 
-  return size / sizeof (STRUCT_UTMP);
+  return 0;
 }
+
+#endif /* HAVE_UTMPNAME */