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

master
sin 2015-10-08 16:43:09 +01:00
parent 09c3caa56d
commit 7b9988c7ff
2 changed files with 11 additions and 3 deletions
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5
flock.1
View File

@ -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
@ -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

9
flock.c
View File

@ -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;
@ -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;