diff mbox series

[uclibc-ng-devel] Re: Possible bug in tempname.c (and its usage)?

Message ID f9daaf58e8a0698f522a76166f59348030cbd1bc.camel@kernkonzept.com
State Changes Requested
Headers show
Series [uclibc-ng-devel] Re: Possible bug in tempname.c (and its usage)? | expand

Commit Message

Sven Linker Feb. 7, 2024, 9:37 a.m. UTC 
Hi,

I'm not sure if this really tests the branch where the issue is, but I
am also not able to come up with a simple test myself (since it
basically relies on predicting the random instantiation of the
template).

But this patch should avoid opening the file, if it already exists.

Cheers,
Sven


On Tue, 2024-02-06 at 15:13 +0100, Marius Melzer wrote:
> Hi,
> 
> On 31.01.24 11:08, Waldemar Brodkorb wrote:
> > do you have a small C test case which might show the failure?
> 
> I unfortunately currently don't have a proper setup to test this, but
> I 
> would expect that this simple loop would deplete all available file 
> descriptors so that at some point, one can't call "open" anymore:
> 
> #include <stdlib.h>
> 
> do {
>    puts("Still fds available\n");
> } while(!strcmp(mktemp("test"),""))
> 
> if(open("somefile.txt") < 0) {
>    puts("fds are depleted. This should not have happened.\n");
> }
> 
> Best regards,
> Marius
>

Comments

Waldemar Brodkorb Feb. 11, 2024, 6:04 a.m. UTC | #1 
Hi Sven,

okay. Can you resent the patch with git format-patch -s origin?
Please add a commit message.

Thanks a lot in advance.
 Waldemar

Sven Linker wrote,

> Hi,
> 
> I'm not sure if this really tests the branch where the issue is, but I
> am also not able to come up with a simple test myself (since it
> basically relies on predicting the random instantiation of the
> template).
> 
> But this patch should avoid opening the file, if it already exists.
> 
> Cheers,
> Sven
> 
> 
> On Tue, 2024-02-06 at 15:13 +0100, Marius Melzer wrote:
> > Hi,
> > 
> > On 31.01.24 11:08, Waldemar Brodkorb wrote:
> > > do you have a small C test case which might show the failure?
> > 
> > I unfortunately currently don't have a proper setup to test this, but
> > I 
> > would expect that this simple loop would deplete all available file 
> > descriptors so that at some point, one can't call "open" anymore:
> > 
> > #include <stdlib.h>
> > 
> > do {
> >    puts("Still fds available\n");
> > } while(!strcmp(mktemp("test"),""))
> > 
> > if(open("somefile.txt") < 0) {
> >    puts("fds are depleted. This should not have happened.\n");
> > }
> > 
> > Best regards,
> > Marius
> > 
> 
> -- 
> Sven Linker
> Tel.: +49 351 41883243
> Kernkonzept GmbH at Dresden, Germany, 
> HRB 31129, CEO Dr.-Ing. Michael Hohmuth
> 
> 

> diff --git a/libc/misc/internals/tempname.c b/libc/misc/internals/tempname.c
> index d3a8ccbd8..f9b714a68 100644
> --- a/libc/misc/internals/tempname.c
> +++ b/libc/misc/internals/tempname.c
> @@ -218,7 +218,8 @@ int attribute_hidden __gen_tempname (char *tmpl, int kind, int flags,
>  			    /* Give up now. */
>  			    return -1;
>  		    } else
> -			fd = 0;
> +			/* File already exists, so return with non-zero value */
> +			return -1;
>  		}
>  	    case __GT_FILE:
>  		fd = open (tmpl, O_RDWR | O_CREAT | O_EXCL | flags, mode);

> _______________________________________________
> devel mailing list -- devel@uclibc-ng.org
> To unsubscribe send an email to devel-leave@uclibc-ng.org
diff mbox series

Patch

diff --git a/libc/misc/internals/tempname.c b/libc/misc/internals/tempname.c
index d3a8ccbd8..f9b714a68 100644
--- a/libc/misc/internals/tempname.c
+++ b/libc/misc/internals/tempname.c
@@ -218,7 +218,8 @@  int attribute_hidden __gen_tempname (char *tmpl, int kind, int flags,
 			    /* Give up now. */
 			    return -1;
 		    } else
-			fd = 0;
+			/* File already exists, so return with non-zero value */
+			return -1;
 		}
 	    case __GT_FILE:
 		fd = open (tmpl, O_RDWR | O_CREAT | O_EXCL | flags, mode);