/* GNU's read utmp module.
- Copyright (C) 1992-2001, 2003, 2004 Free Software Foundation, Inc.
+ Copyright (C) 1992-2001, 2003, 2004, 2005 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
#include <sys/types.h>
#include <sys/stat.h>
+#include <signal.h>
+#include <stdbool.h>
#include <string.h>
#include <stdlib.h>
# include "unlocked-io.h"
#endif
+#ifndef SIZE_MAX
+# define SIZE_MAX ((size_t) -1)
+#endif
+
/* Copy UT->ut_name into storage obtained from malloc. Then remove any
trailing spaces from the copy, NUL terminate it, and return the copy. */
return trimmed_name;
}
+/* Is the utmp entry U desired by the user who asked for OPTIONS? */
+
+static inline bool
+desirable_utmp_entry (STRUCT_UTMP const *u, int options)
+{
+ return ! (options & READ_UTMP_CHECK_PIDS
+ && (UT_PID (u) <= 0
+ || (kill (UT_PID (u), 0) < 0 && errno == ESRCH)));
+}
+
/* 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 -1, setting errno, and don't modify the parameters. */
+ return -1, setting errno, and don't modify the parameters.
+ If OPTIONS & READ_UTMP_CHECK_PIDS is nonzero, omit entries whose
+ process-IDs do not currently exist. */
#ifdef UTMP_NAME_FUNCTION
int
-read_utmp (const char *filename, size_t *n_entries, STRUCT_UTMP **utmp_buf)
+read_utmp (const char *filename, size_t *n_entries, STRUCT_UTMP **utmp_buf,
+ int options)
{
- size_t n_read;
- size_t n_alloc = 4;
- STRUCT_UTMP *utmp = xmalloc (n_alloc * sizeof *utmp);
+ size_t n_read = 0;
+ size_t n_alloc = 0;
+ STRUCT_UTMP *utmp = NULL;
STRUCT_UTMP *u;
/* Ignore the return value for now.
SET_UTMP_ENT ();
- n_read = 0;
while ((u = GET_UTMP_ENT ()) != NULL)
- {
- if (n_read == n_alloc)
- {
- utmp = xnrealloc (utmp, n_alloc, 2 * sizeof *utmp);
- n_alloc *= 2;
- }
- ++n_read;
- utmp[n_read - 1] = *u;
- }
+ if (desirable_utmp_entry (u, options))
+ {
+ if (n_read == n_alloc)
+ utmp = x2nrealloc (utmp, &n_alloc, sizeof *utmp);
+
+ utmp[n_read++] = *u;
+ }
END_UTMP_ENT ();
#else
int
-read_utmp (const char *filename, size_t *n_entries, STRUCT_UTMP **utmp_buf)
+read_utmp (const char *filename, size_t *n_entries, STRUCT_UTMP **utmp_buf,
+ int options)
{
- FILE *utmp;
- struct stat file_stats;
- size_t n_read;
- size_t size;
- STRUCT_UTMP *buf;
-
- utmp = fopen (filename, "r");
- if (utmp == NULL)
+ size_t n_read = 0;
+ size_t n_alloc = 0;
+ STRUCT_UTMP *utmp = NULL;
+ int saved_errno;
+ FILE *f = fopen (filename, "r");
+
+ if (! f)
return -1;
- if (fstat (fileno (utmp), &file_stats) != 0)
- {
- int e = errno;
- fclose (utmp);
- errno = e;
- return -1;
- }
- size = file_stats.st_size;
- buf = xmalloc (size);
- n_read = fread (buf, sizeof *buf, size / sizeof *buf, utmp);
- if (ferror (utmp))
+ for (;;)
{
- int e = errno;
- free (buf);
- fclose (utmp);
- errno = e;
- return -1;
+ if (n_read == n_alloc)
+ utmp = x2nrealloc (utmp, &n_alloc, sizeof *utmp);
+ if (fread (&utmp[n_read], sizeof utmp[n_read], 1, f) == 0)
+ break;
+ n_read += desirable_utmp_entry (&utmp[n_read], options);
}
- if (fclose (utmp) != 0)
+
+ saved_errno = ferror (f) ? errno : 0;
+ if (fclose (f) != 0)
+ saved_errno = errno;
+ if (saved_errno != 0)
{
- int e = errno;
- free (buf);
- errno = e;
+ free (utmp);
+ errno = saved_errno;
return -1;
}
*n_entries = n_read;
- *utmp_buf = buf;
+ *utmp_buf = utmp;
return 0;
}