1 files changed, 82 insertions, 0 deletions
diff --git a/util/sbase/flock.c b/util/sbase/flock.c
new file mode 100644
index 00000000..fc2b6ed6
--- /dev/null
+++ b/util/sbase/flock.c
@@ -0,0 +1,82 @@
+/* See LICENSE file for copyright and license details. */
+#include <sys/file.h>
+#include <sys/wait.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include "util.h"
+
+static void
+usage(void)
+{
+	eprintf("usage: %s [-nosux] file cmd [arg ...]\n", argv0);
+}
+
+int
+main(int argc, char *argv[])
+{
+	int fd, status, savederrno, flags = LOCK_EX, nonblk = 0, oflag = 0;
+	pid_t pid;
+
+	ARGBEGIN {
+	case 'n':
+		nonblk = LOCK_NB;
+		break;
+	case 'o':
+		oflag = 1;
+		break;
+	case 's':
+		flags = LOCK_SH;
+		break;
+	case 'u':
+		flags = LOCK_UN;
+		break;
+	case 'x':
+		flags = LOCK_EX;
+		break;
+	default:
+		usage();
+	} ARGEND
+
+	if (argc < 2)
+		usage();
+
+	if ((fd = open(*argv, O_RDONLY | O_CREAT, 0644)) < 0)
+		eprintf("open %s:", *argv);
+
+	if (flock(fd, flags | nonblk)) {
+		if (nonblk && errno == EWOULDBLOCK)
+			return 1;
+		eprintf("flock:");
+	}
+
+	switch ((pid = fork())) {
+	case -1:
+		eprintf("fork:");
+	case 0:
+		if (oflag && close(fd) < 0)
+			eprintf("close:");
+		argv++;
+		execvp(*argv, argv);
+		savederrno = errno;
+		weprintf("execvp %s:", *argv);
+		_exit(126 + (savederrno == ENOENT));
+	default:
+		break;
+	}
+	if (waitpid(pid, &status, 0) < 0)
+		eprintf("waitpid:");
+
+	if (close(fd) < 0)
+		eprintf("close:");
+
+	if (WIFSIGNALED(status))
+		return 128 + WTERMSIG(status);
+	if (WIFEXITED(status))
+		return WEXITSTATUS(status);
+
+	return 0;
+}