man-pages bug: 211029 https://bugzilla.kernel.org/show_bug.cgi?id=211029 glibc bug: 27143 https://sourceware.org/bugzilla/show_bug.cgi?id=27143 When a command name starts with a hyphen (which is a valid one), the shell's '-c' option interprets the command name as antoher option. This can be workarounded by prepending the command name with a space, as Ciprian pointed out in his bug report. Reported-by: Ciprian Dorin Craciun <ciprian.craciun@xxxxxxxxx> Cc: Florian Weimer <fweimer@xxxxxxxxxx> Signed-off-by: Alejandro Colomar <alx.manpages@xxxxxxxxx> --- Hi Ciprian, If you report a bug to the Austin Group, please CC linux-man@xxxxxxxxxxxxxxx, so that we can add the URL and update the BUGS section if it is ever fixed. man3/system.3 | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/man3/system.3 b/man3/system.3 index aef40417a..5a9318dec 100644 --- a/man3/system.3 +++ b/man3/system.3 @@ -250,6 +250,39 @@ 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 27143](https://sourceware.org/bugzilla/show_bug.cgi?id=27143) +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).). +This behavior is mandated by POSIX. +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
