[v3] system.3: Document bug and workaround when the command name starts with a hypen
Commit Message
man-pages bug: 211029
https://bugzilla.kernel.org/show_bug.cgi?id=211029
Complete workaround
(it was too long for the page, but it may be useful here):
......
$ sudo ln -s -T /usr/bin/echo /usr/bin/-echo;
$ cc -o system_hyphen -x c - ;
int
main(void)
{
system(" -echo Hello world!");
exit(EXIT_SUCCESS);
}
$ ./system_hyphen;
Hello world!
Reported-by: Ciprian Dorin Craciun <ciprian.craciun@gmail.com>
Cc: Florian Weimer <fweimer@redhat.com>
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
---
Hi Michael,
I forgot to remove some escapings in the commit message in v2.
I hope it arrives in time :)
Cheers,
Alex
man3/system.3 | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
@@ -255,6 +255,26 @@ 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 to
+.BR sh (1).)
+To work around this problem,
+prepend the command with a space as in the following call:
+.PP
+.RS 4
+.EX
+ system(" \-unfortunate\-command\-name");
+.EE
+.RE
.SH SEE ALSO
.BR sh (1),
.BR execve (2),