On 1/8/21 3:28 PM, Alejandro Colomar (man-pages) wrote: > > > On 1/8/21 3:22 PM, Alejandro Colomar wrote: >> man-pages bug: 211029 >> https://bugzilla.kernel.org/show_bug.cgi?id=211029 >> >> Complete workaround > > Maybe a bit more readable: > Complete workaround example Changed. Thanks, Michael > > >> (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 - ; >> #include <stdlib.h> >> >> int >> main(void) >> { >> system(" -echo Hello world!"); >> exit(EXIT_SUCCESS); >> } >> >> $ ./system_hyphen; >> Hello world! >> >> Reported-by: Ciprian Dorin Craciun <ciprian.craciun@xxxxxxxxx> >> Cc: Florian Weimer <fweimer@xxxxxxxxxx> >> Signed-off-by: Alejandro Colomar <alx.manpages@xxxxxxxxx> >> --- >> >> D'oh! >> >> man3/system.3 | 20 ++++++++++++++++++++ >> 1 file changed, 20 insertions(+) >> >> diff --git a/man3/system.3 b/man3/system.3 >> index 753d46f7d..ead35ab30 100644 >> --- a/man3/system.3 >> +++ b/man3/system.3 >> @@ -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), >> > -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/
