1 files changed, 138 insertions, 0 deletions
diff --git a/lib/replace/closefrom.c b/lib/replace/closefrom.c
new file mode 100644
index 0000000..bef53e4
--- /dev/null
+++ b/lib/replace/closefrom.c
@@ -0,0 +1,138 @@
+/*
+ * Unix SMB/CIFS implementation.
+ * Samba utility functions
+ * Copyright (C) Volker Lendecke 2016
+ *
+ *   ** NOTE! The following LGPL license applies to the replace
+ *   ** library. This does NOT imply that all of Samba is released
+ *   ** under the LGPL
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "replace.h"
+#include <dirent.h>
+#include <unistd.h>
+#include <limits.h>
+
+static int closefrom_sysconf(int lower)
+{
+	long max_files, fd;
+
+	max_files = sysconf(_SC_OPEN_MAX);
+	if (max_files == -1) {
+		max_files = 65536;
+	}
+
+	for (fd=lower; fd<max_files; fd++) {
+		close(fd);
+	}
+
+	return 0;
+}
+
+static int closefrom_procfs(int lower)
+{
+	DIR *dirp;
+	int dir_fd;
+	struct dirent *dp;
+	int *fds = NULL;
+	size_t num_fds = 0;
+	size_t fd_array_size = 0;
+	size_t i;
+	int ret = ENOMEM;
+
+	dirp = opendir("/proc/self/fd");
+	if (dirp == NULL) {
+		return errno;
+	}
+
+	dir_fd = dirfd(dirp);
+	if (dir_fd == -1) {
+		ret = errno;
+		goto fail;
+	}
+
+	while ((dp = readdir(dirp)) != NULL) {
+		char *endptr;
+		unsigned long long fd;
+
+		errno = 0;
+
+		fd = strtoull(dp->d_name, &endptr, 10);
+		if ((fd == 0) && (errno == EINVAL)) {
+			continue;
+		}
+		if ((fd == ULLONG_MAX) && (errno == ERANGE)) {
+			continue;
+		}
+		if (*endptr != '\0') {
+			continue;
+		}
+		if (fd == dir_fd) {
+			continue;
+		}
+		if (fd > INT_MAX) {
+			continue;
+		}
+		if (fd < lower) {
+			continue;
+		}
+
+		if (num_fds >= (fd_array_size / sizeof(int))) {
+			void *tmp;
+
+			if (fd_array_size == 0) {
+				fd_array_size = 16 * sizeof(int);
+			} else {
+				if (fd_array_size + fd_array_size <
+				    fd_array_size) {
+					/* overflow */
+					goto fail;
+				}
+				fd_array_size = fd_array_size + fd_array_size;
+			}
+
+			tmp = realloc(fds, fd_array_size);
+			if (tmp == NULL) {
+				goto fail;
+			}
+			fds = tmp;
+		}
+
+		fds[num_fds++] = fd;
+	}
+
+	for (i=0; i<num_fds; i++) {
+		close(fds[i]);
+	}
+
+	ret = 0;
+fail:
+	closedir(dirp);
+	free(fds);
+	return ret;
+}
+
+int rep_closefrom(int lower)
+{
+	int ret;
+
+	ret = closefrom_procfs(lower);
+	if (ret == 0) {
+		return 0;
+	}
+
+	return closefrom_sysconf(lower);
+}