Date: Sun, 23 Nov 2003 16:14:08 +0200 From: Enache Adrian <enache@rdslink.ro> To: current@freebsd.org Subject: [PATCH] libc_r bug: successful close(2) sets errno to ENOTTY Message-ID: <20031123141408.GA1426@ratsnest.hole>
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$ cc close.c -o close && ./close
0
0
$ cc close.c -lc_r -o close && ./close
0
25
$ cat close.c
#include <errno.h>
main()
{
int fd = open("/dev/null", 1);
printf("%d\n", errno);
close(fd);
printf("%d\n", errno);
}
This confuses rather badly applications which assume errno is meaningful.
It could be fixed easily by repeating the trick from uthread/uthread_fd.c:
--- /arc/freebsd/src/lib/libc_r/uthread/uthread_close.c Tue Jun 10 23:42:27 2003
+++ lib/libc_r/uthread/uthread_close.c Sun Nov 23 00:50:30 2003
@@ -87,10 +87,12 @@ _close(int fd)
*/
if ((S_ISREG(sb.st_mode) || S_ISCHR(sb.st_mode))
&& (_thread_fd_getflags(fd) & O_NONBLOCK) == 0) {
+ int saved_errno = errno;
/* Get the current flags: */
flags = __sys_fcntl(fd, F_GETFL, NULL);
/* Clear the nonblocking file descriptor flag: */
__sys_fcntl(fd, F_SETFL, flags & ~O_NONBLOCK);
+ errno = saved_errno;
}
/* XXX: Assumes well behaved threads. */
Regards,
Adi
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