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Re: [RFC] Avoid invalid parameter warnings in C runtime function for mingw builtr GDB
- From: Eli Zaretskii <eliz at gnu dot org>
- To: Pierre Muller <pierre dot muller at ics-cnrs dot unistra dot fr>
- Cc: gdb-patches at sourceware dot org
- Date: Fri, 09 Aug 2013 17:09:38 +0300
- Subject: Re: [RFC] Avoid invalid parameter warnings in C runtime function for mingw builtr GDB
- References: <"002201ce9414$7e0d7130$7a285390$ at muller"@ics-cnrs.unistra.fr>
- Reply-to: Eli Zaretskii <eliz at gnu dot org>
> From: "Pierre Muller" <pierre.muller@ics-cnrs.unistra.fr>
> Date: Thu, 8 Aug 2013 10:51:37 +0200
>
> Lately I got several warnings with mingw built
> GDB's:
>
> warning: Invalid parameter passed to C runtime function.
>
> Use the new "set stop-on-debug-string-event on"
> command submitted previously in
> http://sourceware.org/ml/gdb-patches/2013-08/msg00236.html
>
> I was able to trace this down to
> the fopen call with mode that to "re".
> As stated in the source, the "e" mode is a glibc extension
> about close on exec which generates this warning.
>
> The patch below excludes this code if __MINGW32__ is defined,
> but maybe it should be excluded if O_CLOEXEC is zero?
Actually, if we want this to be portable, we should have a function to
make a file handle be non-inheritable, instead of relying on glibc
extensions. There _is_ a way to make a file handle non-inheritable on
Windows.
> diff -u -p -r1.7 filestuff.c
> --- src/gdb/common/filestuff.c 26 Jun 2013 08:01:55 -0000 1.7
> +++ src/gdb/common/filestuff.c 7 Aug 2013 12:35:55 -0000
> @@ -311,6 +311,7 @@ FILE *
> gdb_fopen_cloexec (const char *filename, const char *opentype)
> {
> FILE *result = NULL;
> +#ifndef __MINGW32__
> static int fopen_e_ever_failed;
>
> if (!fopen_e_ever_failed)
> @@ -320,17 +321,21 @@ gdb_fopen_cloexec (const char *filename,
> copy = alloca (strlen (opentype) + 2);
> strcpy (copy, opentype);
> /* This is a glibc extension but we try it unconditionally on
> - this path. */
> + this path, except when using Windows OS msvcrt dll,
> + in order to avoid a output debug string event. */
> strcat (copy, "e");
> result = fopen (filename, copy);
> }
> +#endif
>
> if (result == NULL)
> {
> /* Fallback. */
> result = fopen (filename, opentype);
> +#ifndef __MINGW32__
> if (result != NULL)
> fopen_e_ever_failed = 1;
> +#endif
> }
>
> if (result != NULL)
Wouldn't it be better to instead initialize fopen_e_ever_failed to 1
on MinGW? Then the rest of the code will "just work", no?