pci-assign: do not test path with access() before opening

Using access() is a time-of-check/time-of-use race condition.  It is
okay to use them to provide better error messages, but that is pretty
much it.

In this case we can get the same error from fopen(), so just use
strerror and errno there---which actually improves the error
message most of the time.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

diff --git a/hw/i386/pci-assign-load-rom.c b/hw/i386/pci-assign-load-rom.c
index 34a3a7ed7f3c49da92effc6612bcb08e631edaa6..e40b586b92426a44daf0afb7da96683eb9e63a46 100644 (file)
--- a/hw/i386/pci-assign-load-rom.c
+++ b/hw/i386/pci-assign-load-rom.c
@@ -45,14 +45,10 @@ void *pci_assign_dev_load_option_rom(PCIDevice *dev, struct Object *owner,
         return NULL;
     }
 
-    if (access(rom_file, F_OK)) {
-        error_report("pci-assign: Insufficient privileges for %s", rom_file);
-        return NULL;
-    }
-
     /* Write "1" to the ROM file to enable it */
     fp = fopen(rom_file, "r+");
     if (fp == NULL) {
+        error_report("pci-assign: Cannot open %s: %s", rom_file, strerror(errno));
         return NULL;
     }
     val = 1;