Hi all,
I've been tracking down a bug in a Fortran program on a newlib target and it
boils down to fallback_access doing something bad.
The unconditional calls to close cause havoc when open doesn't get called due
to the short-circuiting in the if-statement above
because the fd is uninitialised. In my environment GCC ends up calling close on
file descriptor 0, thus trying to close stdin.
This patch tightens up the calling so that close is called only when the
corresponding open call succeeded.
With this my runtime failure disappears.
Bootstrapped and tested on aarch64-none-linux-gnu.
Though that doesn't exercise this call I hope it's an obviously correct change.
Ok for trunk and the branches?
Thanks,
Kyrill
2018-09-14 Kyrylo Tkachov <kyrylo.tkac...@arm.com>
* io/unix.c (fallback_access): Avoid calling close on
uninitialized file descriptor.
diff --git a/libgfortran/io/unix.c b/libgfortran/io/unix.c
index 61e9f7997b25819514af546b50aa1d00b1d116f9..8081d6f96b2f6cd2489e876c8921cfb3510287ca 100644
--- a/libgfortran/io/unix.c
+++ b/libgfortran/io/unix.c
@@ -149,13 +149,21 @@ fallback_access (const char *path, int mode)
{
int fd;
- if ((mode & R_OK) && (fd = open (path, O_RDONLY)) < 0)
- return -1;
- close (fd);
+ if (mode & R_OK)
+ {
+ if ((fd = open (path, O_RDONLY)) < 0)
+ return -1;
+ else
+ close (fd);
+ }
- if ((mode & W_OK) && (fd = open (path, O_WRONLY)) < 0)
- return -1;
- close (fd);
+ if (mode & W_OK)
+ {
+ if ((fd = open (path, O_WRONLY)) < 0)
+ return -1;
+ else
+ close (fd);
+ }
if (mode == F_OK)
{
