Eric Blake wrote:
> Instead of using -- to force sh to realize the command being passed is
> intended to be a script to run (even if it starts with - or +), it is
> also possible to prepend a space.
Indeed, that it simpler than testing whether the command starts with - or +.
> I'm thinking of trying the alternative of not injecting "--" after
> all, but instead munging the given argument to supply a leading space.
> But that we need a new version of your patch. Do you want to try and
> rework it along those lines, or should I make time for that?
Find attached a proposed patch. Tested on FreeBSD 13.1 and AIX 7.2; with
it, all m4 tests pass.
Bruno
>From e09b3ff04cbfce7073de5c7fd3812ffe9c48bac3 Mon Sep 17 00:00:00 2001
From: Bruno Haible <br...@clisp.org>
Date: Sat, 14 Jan 2023 20:41:15 +0100
Subject: [PATCH] syscmd: Make it work again for most commands on FreeBSD and
AIX.
Regression from 2021-11-19. Fix proposed by Eric Blake.
* src/builtin.c (m4_syscmd): On Unix, prepend a space to the command before
executing it.
(m4_esyscmd): Likewise.
---
src/builtin.c | 38 ++++++++++++++++++++++++++++++--------
1 file changed, 30 insertions(+), 8 deletions(-)
diff --git a/src/builtin.c b/src/builtin.c
index c7349596..38019f10 100644
--- a/src/builtin.c
+++ b/src/builtin.c
@@ -945,10 +945,10 @@ static void
m4_syscmd (struct obstack *obs MAYBE_UNUSED, int argc, token_data **argv)
{
const char *cmd = ARG (1);
+ char *xcmd = NULL;
int status;
int sig_status;
- int slot = 3;
- const char *prog_args[5] = { "sh", "-c", "--" };
+ const char *prog_args[4] = { "sh", "-c" };
if (bad_argc (argv[0], argc, 2, 2) || !*cmd)
{
/* The empty command is successful. */
@@ -962,10 +962,20 @@ m4_syscmd (struct obstack *obs MAYBE_UNUSED, int argc, token_data **argv)
{
prog_args[0] = "cmd";
prog_args[1] = "/c";
- slot = 2;
+ prog_args[2] = cmd;
}
+ else
#endif
- prog_args[slot] = cmd;
+ {
+ /* If cmd starts with '-' or '+', 'sh -c "$cmd"' is not guaranteed to
+ work. If we could assume a POSIX compliant SYSCMD_SHELL, we could use
+ 'sh -c -- "$cmd"'. But it does not work with /bin/sh on FreeBSD 13
+ and AIX 7, and on these platforms 'bash' is not guaranteed to be
+ installed. Therefore use 'sh -c " $cmd"' instead. */
+ xcmd = xasprintf (" %s", cmd);
+ prog_args[2] = xcmd;
+ }
+ prog_args[3] = NULL;
errno = 0;
status = execute (ARG (0), SYSCMD_SHELL, prog_args, NULL, false,
false, false, false, true, false, &sig_status);
@@ -980,14 +990,15 @@ m4_syscmd (struct obstack *obs MAYBE_UNUSED, int argc, token_data **argv)
M4ERROR ((warning_status, errno, _("cannot run command `%s'"), cmd));
sysval = status;
}
+ free (xcmd);
}
static void
m4_esyscmd (struct obstack *obs, int argc, token_data **argv)
{
const char *cmd = ARG (1);
- int slot = 3;
- const char *prog_args[5] = { "sh", "-c", "--" };
+ char *xcmd = NULL;
+ const char *prog_args[4] = { "sh", "-c" };
pid_t child;
int fd;
FILE *pin;
@@ -1007,10 +1018,20 @@ m4_esyscmd (struct obstack *obs, int argc, token_data **argv)
{
prog_args[0] = "cmd";
prog_args[1] = "/c";
- slot = 2;
+ prog_args[2] = cmd;
}
+ else
#endif
- prog_args[slot] = cmd;
+ {
+ /* If cmd starts with '-' or '+', 'sh -c "$cmd"' is not guaranteed to
+ work. If we could assume a POSIX compliant SYSCMD_SHELL, we could use
+ 'sh -c -- "$cmd"'. But it does not work with /bin/sh on FreeBSD 13
+ and AIX 7, and on these platforms 'bash' is not guaranteed to be
+ installed. Therefore use 'sh -c " $cmd"' instead. */
+ xcmd = xasprintf (" %s", cmd);
+ prog_args[2] = xcmd;
+ }
+ prog_args[3] = NULL;
errno = 0;
child = create_pipe_in (ARG (0), SYSCMD_SHELL, prog_args, NULL,
NULL, false, true, false, &fd);
@@ -1067,6 +1088,7 @@ m4_esyscmd (struct obstack *obs, int argc, token_data **argv)
M4ERROR ((warning_status, errno, _("cannot run command `%s'"), cmd));
sysval = status;
}
+ free (xcmd);
}
static void
--
2.34.1
