lslogins: also add readutmp.c

1 files changed, 76 insertions, 0 deletions

diff --git a/lib/readutmp.c b/lib/readutmp.c
new file mode 100644
index 000000000..4e8a0845c
--- /dev/null
+++ b/lib/readutmp.c
@@ -0,0 +1,76 @@
+/* GNU's read utmp module.
+
+	 Copyright (C) 1992-2001, 2003-2006, 2009-2014 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
+	 the Free Software Foundation; either version 3 of the License, or
+	 (at your option) any later version.
+
+	 This program is distributed in the hope that it will be useful,
+	 but WITHOUT ANY WARRANTY; without even the implied warranty of
+	 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	See the
+	 GNU General Public License for more details.
+
+	 You should have received a copy of the GNU General Public License
+	 along with this program.	If not, see <http://www.gnu.org/licenses/>.	*/
+
+/* Written by jla; revised by djm */
+/* extracted for util-linux by ooprala */
+
+#include <errno.h>
+#include <stdio.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdint.h>
+
+#include "xalloc.h"
+#include "readutmp.h"
+
+/* Read the utmp entries corresponding to file FILE 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.
+	 If OPTIONS & READ_UTMP_CHECK_PIDS is nonzero, omit entries whose
+	 process-IDs do not currently exist.	*/
+int
+read_utmp (char const *file, size_t *n_entries, struct utmp **utmp_buf)
+{
+	size_t n_read = 0;
+	size_t n_alloc = 0;
+	struct utmp *utmp = NULL;
+	struct utmp *u;
+
+	/* Ignore the return value for now.
+		 Solaris' utmpname returns 1 upon success -- which is contrary
+		 to what the GNU libc version does.	In addition, older GNU libc
+		 versions are actually void.	 */
+	utmpname(file);
+
+	setutent();
+
+	errno = 0;
+	while ((u = getutent()) != NULL) {
+		if (n_read == n_alloc) {
+			n_alloc += 32;
+			utmp = xrealloc(utmp, n_alloc * sizeof (struct utmp));
+			if (!utmp)
+				return -1;
+		}
+		utmp[n_read++] = *u;
+	}
+	if (!u && errno)
+		return -1;
+
+	endutent();
+
+	*n_entries = n_read;
+	*utmp_buf = utmp;
+
+	return 0;
+}