[hackers] [sbase] Implement -o for flock(1) to close fd before exec || sin

From: <git_AT_suckless.org>
Date: Mon, 26 Oct 2015 12:55:50 +0100 (CET)

commit 7b9988c7fffa6a3d44270401246079e77af14614
Author: sin <sin_AT_2f30.org>
AuthorDate: Thu Oct 8 16:43:09 2015 +0100
Commit: sin <sin_AT_2f30.org>
CommitDate: Mon Oct 26 11:55:41 2015 +0000

    Implement -o for flock(1) to close fd before exec

diff --git a/flock.1 b/flock.1
index 9632a10..84a0098 100644
--- a/flock.1
+++ b/flock.1
_AT_@ -6,7 +6,7 @@
 .Nd tool to manage locks on files
 .Sh SYNOPSIS
 .Nm
-.Op Fl nsux
+.Op Fl nosux
 .Ar file
 .Ar cmd Op arg ...
 .Sh DESCRIPTION
_AT_@ -20,6 +20,9 @@ does not exist, it will be created.
 .It Fl n
 Set non-blocking mode on the lock. Fail immediately if the lock
 cannot be acquired.
+.It Fl o
+Close the file descriptor before exec to avoid having the exec'ed
+program holding on to the lock.
 .It Fl s
 Acquire a shared lock.
 .It Fl u
diff --git a/flock.c b/flock.c
index 112ce4a..292821f 100644
--- a/flock.c
+++ b/flock.c
_AT_@ -12,19 +12,22 @@
 static void
 usage(void)
 {
- eprintf("usage: %s [-nsux] file cmd [arg ...]\n", argv0);
+ eprintf("usage: %s [-nosux] file cmd [arg ...]\n", argv0);
 }
 
 int
 main(int argc, char *argv[])
 {
- int fd, status, savederrno, flags = LOCK_EX, nonblk = 0;
+ 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;
_AT_@ -54,6 +57,8 @@ main(int argc, char *argv[])
         case -1:
                 eprintf("fork:");
         case 0:
+ if (oflag && close(fd) < 0)
+ eprintf("close:");
                 argv++;
                 execvp(*argv, argv);
                 savederrno = errno;
Received on Mon Oct 26 2015 - 12:55:50 CET