From: "Sören Tempel" <soeren+git@soeren-tempel.net>
To: musl@lists.openwall.com
Subject: [musl] [PATCH v2] cuserid: support invocation with a NULL pointer argument
Date: Wed, 29 Jan 2020 12:20:07 +0100 [thread overview]
Message-ID: <20200129112007.17575-1-soeren+git@soeren-tempel.net> (raw)
I did not manage to find a copy of IEEE 1003.1-1988 (the last POSIX
version where cuserid was last standardized) the Single UNIX
specification version 2 does state the following though [1]:
If s is a null pointer, this representation is generated in an
area that may be static (and thus overwritten by subsequent
calls to cuserid()), the address of which is returned.
Even though this a legacy function it would therefore be nice for musl
to support usage with a NULL pointer. I ran into this on Alpine Linux
when using cdparanoia [2] which uses cuserid like this and therefore
caused a crash on my system.
[1]: https://pubs.opengroup.org/onlinepubs/7908799/xsh/cuserid.html
[2]: https://xiph.org/paranoia/index.html
---
src/legacy/cuserid.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/src/legacy/cuserid.c b/src/legacy/cuserid.c
index 4e78798d..fd7832e4 100644
--- a/src/legacy/cuserid.c
+++ b/src/legacy/cuserid.c
@@ -5,10 +5,12 @@
char *cuserid(char *buf)
{
+ static char usridbuf[L_cuserid];
struct passwd pw, *ppw;
long pwb[256];
if (getpwuid_r(geteuid(), &pw, (void *)pwb, sizeof pwb, &ppw))
return 0;
+ if (!buf) buf = usridbuf;
snprintf(buf, L_cuserid, "%s", pw.pw_name);
return buf;
}
next reply other threads:[~2020-01-29 11:34 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-29 11:20 Sören Tempel [this message]
2020-01-29 11:59 ` Sören Tempel
2020-03-22 9:51 ` Sören Tempel
2020-03-22 15:05 ` Rich Felker
2021-02-13 19:06 ` Rich Felker
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