[gcc r12-5568] Fix PR 19089: Environment variable TMP may yield gcc: abort

[Andrew Pinski <pinskia@gcc.gnu.org>]

https://gcc.gnu.org/g:68332ab7ec58a89660db82569c5f4c2251d59741

commit r12-5568-g68332ab7ec58a89660db82569c5f4c2251d59741
Author: Andrew Pinski <apinski@marvell.com>
Date:   Sat Nov 27 18:16:50 2021 -0800

    Fix PR 19089: Environment variable TMP may yield gcc: abort
    
    Even though I cannot reproduce the ICE any more, this is still
    a bug. We check already to see if we can access the directory
    but never check to see if the path is actually a directory.
    
    This adds the check and now we reject the file as not usable
    as a tmp directory.
    
    OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.
    
    libiberty/ChangeLog:
    
            * make-temp-file.c (try_dir): Check to see if the dir
            is actually a directory.

Diff:
---
 libiberty/make-temp-file.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/libiberty/make-temp-file.c b/libiberty/make-temp-file.c
index 31f87fbcfde..948f10ae058 100644
--- a/libiberty/make-temp-file.c
+++ b/libiberty/make-temp-file.c
@@ -39,6 +39,10 @@ Boston, MA 02110-1301, USA.  */
 #if defined(_WIN32) && !defined(__CYGWIN__)
 #include <windows.h>
 #endif
+#if HAVE_SYS_STAT_H
+#include <sys/stat.h>
+#endif
+
 
 #ifndef R_OK
 #define R_OK 4
@@ -76,7 +80,17 @@ try_dir (const char *dir, const char *base)
     return base;
   if (dir != 0
       && access (dir, R_OK | W_OK | X_OK) == 0)
-    return dir;
+    {
+      /* Check to make sure dir is actually a directory. */
+#ifdef S_ISDIR
+      struct stat s;
+      if (stat (dir, &s))
+	return NULL;
+      if (!S_ISDIR (s.st_mode))
+	return NULL;
+#endif
+      return dir;
+    }
   return 0;
 }