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access on non-existing file and catchsegv
- To: libc-alpha at sources dot redhat dot com
- Subject: access on non-existing file and catchsegv
- From: Andreas Jaeger <aj at suse dot de>
- Date: Sun, 01 Jul 2001 14:29:19 +0200
- Cc: ma at dt dot e-technik dot uni-dortmund dot de
Matthias reports in PR libc/2345 that catchsegv only calls addrline if
the file already exists.
Looking into the problem in more detail, I found that we have the
following code in sysdeps/generic/segfault.c:
/* Preserve the output file name if there is any given. */
name = getenv ("SEGFAULT_OUTPUT_NAME");
if (name != NULL && name[0] != '\0' && access (name, R_OK | W_OK) == 0)
fname = __strdup (name);
Since the file does not exist, access sets ENOENT and returns with -1
- and we do not create the file in that case. Therefore the test is
broken. The question is now how to fix this.
Matthias found as a workaround to just touch the file in catchsegv but
this does not work in general.
I propose to check also whether the file exists.
I'm appending a patch. What do you think?
Andreas
2001-07-01 Andreas Jaeger <aj@suse.de>
* sysdeps/generic/segfault.c (install_handler): Handle case that
the output file does not exists.
Closes PR libc/2345.
============================================================
Index: sysdeps/generic/segfault.c
--- sysdeps/generic/segfault.c 2001/01/12 17:34:37 1.14
+++ sysdeps/generic/segfault.c 2001/07/01 12:14:04
@@ -237,6 +237,11 @@
/* Preserve the output file name if there is any given. */
name = getenv ("SEGFAULT_OUTPUT_NAME");
- if (name != NULL && name[0] != '\0' && access (name, R_OK | W_OK) == 0)
- fname = __strdup (name);
+ if (name != NULL && name[0] != '\0')
+ {
+ int ret = access (name, R_OK | W_OK);
+
+ if (ret == 0 || (ret == -1 && errno == ENOENT))
+ fname = __strdup (name);
+ }
}
--
Andreas Jaeger
SuSE Labs aj@suse.de
private aj@arthur.inka.de
http://www.suse.de/~aj