| Message ID | 20210104180420.74092-1-alx.manpages@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | system.3: Document bug and workaround when the command name starts with a hypen | expand |
Hi Michael, See a few corrections below. Cheers, Alex On 1/4/21 7:04 PM, Alejandro Colomar wrote: > 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 option to > +.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!"); \-echo > + exit(EXIT_SUCCESS); > +} > +.PP > +.RB "$" " sudo ln \-s \-T /usr/bin/echo /usr/bin/\-echo;" > +.RB "$" " cc \-o system_hyphen system_hyphen.c;" > +.RB "$" " ./system_hyphen;" > +Hello world! > +.EE > +.RE > .SH SEE ALSO > .BR sh (1), > .BR execve (2), >
D'oh On 1/4/21 7:32 PM, Alejandro Colomar (man-pages) wrote: > Hi Michael, > > See a few corrections below. > > Cheers, > > Alex > > On 1/4/21 7:04 PM, Alejandro Colomar wrote: >> man-pages bug: 211029 >> https://bugzilla.kernel.org/show_bug.cgi?id=211029 >> >> Reported-by: Ciprian Dorin Craciun <ciprian.craciun@gmail.com> >> Cc: Florian Weimer <fweimer@redhat.com> >> Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com> >> --- >> man3/system.3 | 34 ++++++++++++++++++++++++++++++++++ >> 1 file changed, 34 insertions(+) >> >> diff --git a/man3/system.3 b/man3/system.3 >> index aef40417a..0310d9a04 100644 >> --- a/man3/system.3 >> +++ b/man3/system.3 >> @@ -250,6 +250,40 @@ are not executed. >> Such risks are especially grave when using >> .BR system () >> from a privileged program. >> +.SH BUGS >> +./" [BUG 211029](https://bugzilla.kernel.org/show_bug.cgi?id=211029) >> +./" [Glibc bug](https://sourceware.org/bugzilla/show_bug.cgi?id=27143) >> +./" [POSIX bug](https://www.austingroupbugs.net/view.php?id=1440) s%/%\\% >> +If the command name starts with a hyphen, >> +.BR sh (1) >> +interprets the command name as an option, >> +and the behavior is undefined >> +(See the >> +.B \-c >> +option in > > option to > >> +.BR sh (1).). >> +To work around this problem, >> +prepend the command with a space as below: >> +.PP >> +.RS 4 >> +.EX >> +/* system_hyphen.c */ >> + >> +#include <stdlib.h> >> + >> +int >> +main(void) >> +{ >> + system(" -echo Hello world!"); > > \-echo > >> + exit(EXIT_SUCCESS); >> +} >> +.PP >> +.RB "$" " 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), >> >
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),
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(+)