1 files changed, 93 insertions, 0 deletions
diff --git a/lib/cmdline/closefrom_except.c b/lib/cmdline/closefrom_except.c
new file mode 100644
index 0000000..fe4e0cc
--- /dev/null
+++ b/lib/cmdline/closefrom_except.c
@@ -0,0 +1,93 @@
+/*
+ *  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/>.
+ */
+
+#include "replace.h"
+#include "closefrom_except.h"
+#include <popt.h>
+
+int closefrom_except(int lower, int *fds, size_t num_fds)
+{
+	size_t i;
+	int max_keep = -1;
+	int fd, ret;
+
+	for (i=0; i<num_fds; i++) {
+		max_keep = MAX(max_keep, fds[i]);
+	}
+	if (max_keep == -1) {
+		return 0;
+	}
+
+	for (fd = lower; fd < max_keep; fd++) {
+		bool keep = false;
+
+		/*
+		 * O(num_fds*max_keep), but we expect the number of
+		 * fds to keep to be very small, typically 0,1,2 and
+		 * very few more.
+		 */
+		for (i=0; i<num_fds; i++) {
+			if (fd == fds[i]) {
+				keep = true;
+				break;
+			}
+		}
+		if (keep) {
+			continue;
+		}
+		ret = close(fd);
+		if ((ret == -1) && (errno != EBADF)) {
+			return errno;
+		}
+	}
+
+	closefrom(MAX(lower, max_keep+1));
+	return 0;
+}
+
+int closefrom_except_fd_params(
+	int lower,
+	size_t num_fd_params,
+	const char *fd_params[],
+	int argc,
+	const char *argv[])
+{
+	int fds[num_fd_params];
+	size_t i;
+	struct poptOption long_options[num_fd_params + 1];
+	poptContext pc;
+	int ret;
+
+	for (i=0; i<num_fd_params; i++) {
+		fds[i] = -1;
+		long_options[i] = (struct poptOption) {
+			.longName = fd_params[i],
+			.argInfo = POPT_ARG_INT,
+			.arg = &fds[i],
+		};
+	}
+	long_options[num_fd_params] = (struct poptOption) { .longName=NULL, };
+
+	pc = poptGetContext(argv[0], argc, argv, long_options, 0);
+
+	while ((ret = poptGetNextOpt(pc)) != -1) {
+		/* do nothing */
+	}
+
+	poptFreeContext(pc);
+
+	ret = closefrom_except(lower, fds, ARRAY_SIZE(fds));
+	return ret;
+}