From: Alejandro Colomar <alx.manpages@gmail.com>
To: mtk.manpages@gmail.com
Cc: libc-alpha@sourceware.org,
Alejandro Colomar <alx.manpages@gmail.com>,
linux-man@vger.kernel.org,
Ciprian Dorin Craciun <ciprian.craciun@gmail.com>,
Florian Weimer <fweimer@redhat.com>
Subject: [PATCH] system.3: Document bug and workaround when the command name starts with a hypen
Date: Mon, 4 Jan 2021 19:04:21 +0100 [thread overview]
Message-ID: <20210104180420.74092-1-alx.manpages@gmail.com> (raw)
In-Reply-To: <CA+Tk8fykJjf=KzYjW7YMonnZ1qAdQJhqKDRrX0FNGyAYjSnkqg@mail.gmail.com>
man-pages bug: 211029
https://bugzilla.kernel.org/show_bug.cgi?id=211029
Reported-by: Ciprian Dorin Craciun <ciprian.craciun@gmail.com>
Cc: Florian Weimer <fweimer@redhat.com>
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
---
man3/system.3 | 34 ++++++++++++++++++++++++++++++++++
1 file changed, 34 insertions(+)
diff --git a/man3/system.3 b/man3/system.3
index aef40417a..0310d9a04 100644
--- a/man3/system.3
+++ b/man3/system.3
@@ -250,6 +250,40 @@ are not executed.
Such risks are especially grave when using
.BR system ()
from a privileged program.
+.SH BUGS
+./" [BUG 211029](https://bugzilla.kernel.org/show_bug.cgi?id=211029)
+./" [Glibc bug](https://sourceware.org/bugzilla/show_bug.cgi?id=27143)
+./" [POSIX bug](https://www.austingroupbugs.net/view.php?id=1440)
+If the command name starts with a hyphen,
+.BR sh (1)
+interprets the command name as an option,
+and the behavior is undefined
+(See the
+.B \-c
+option in
+.BR sh (1).).
+To work around this problem,
+prepend the command with a space as below:
+.PP
+.RS 4
+.EX
+/* system_hyphen.c */
+
+#include <stdlib.h>
+
+int
+main(void)
+{
+ system(" -echo Hello world!");
+ exit(EXIT_SUCCESS);
+}
+.PP
+.RB "$" " sudo ln \-s \-T /usr/bin/echo /usr/bin/\-echo;"
+.RB "$" " cc \-o system_hyphen system_hyphen.c;"
+.RB "$" " ./system_hyphen;"
+Hello world!
+.EE
+.RE
.SH SEE ALSO
.BR sh (1),
.BR execve (2),
--
2.29.2
next parent reply other threads:[~2021-01-04 18:05 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CA+Tk8fykJjf=KzYjW7YMonnZ1qAdQJhqKDRrX0FNGyAYjSnkqg@mail.gmail.com>
2021-01-04 18:04 ` Alejandro Colomar [this message]
2021-01-04 18:32 ` Alejandro Colomar (man-pages)
2021-01-04 20:02 ` Alejandro Colomar (man-pages)
2021-01-08 14:20 ` [PATCH v3] " Alejandro Colomar
2021-01-08 14:22 ` [PATCH v4] " Alejandro Colomar
2021-01-08 14:28 ` Alejandro Colomar (man-pages)
2021-01-18 15:28 ` Ping: " Alejandro Colomar (man-pages)
2021-01-18 15:37 ` Michael Kerrisk (man-pages)
2021-01-18 15:36 ` Michael Kerrisk (man-pages)
2021-01-18 15:35 ` Michael Kerrisk (man-pages)
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