Many callsites run "sh -c $CMD" to run $CMD. We can make it
a little simpler for them by factoring out the munging of
argv.
For simple cases with no arguments, this doesn't help much, but:
1. For cases with arguments, we save the caller from
having to build the appropriate shell snippet.
2. We can later optimize to avoid the shell when
there are no metacharacters in the program.
Signed-off-by: Jeff King <peff@xxxxxxxx>
---
I made the matching tweak to the Windows half of run-command, but I
don't actually have a box to test it on.
I modeled this after execv_git_cmd. Like that function, I try to release
the allocated argv on error. However, we do actually leak the strbuf
memory in one case. I'm not sure how much we care. On unix, this will
always happen in a forked process which will either exec or die. On
Windows, we seem to already be leaking the prepared argv for the git_cmd
case (and now we leak the shell_cmd case, too).
run-command.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
run-command.h | 2 ++
2 files changed, 47 insertions(+), 0 deletions(-)
diff --git a/run-command.c b/run-command.c
index cf2d8f7..dc65903 100644
--- a/run-command.c
+++ b/run-command.c
@@ -15,6 +15,46 @@ static inline void dup_devnull(int to)
close(fd);
}
+static const char **prepare_shell_cmd(const char **argv)
+{
+ int argc, nargc = 0;
+ const char **nargv;
+
+ for (argc = 0; argv[argc]; argc++)
+ ; /* just counting */
+ /* +1 for NULL, +3 for "sh -c" plus extra $0 */
+ nargv = xmalloc(sizeof(*nargv) * (argc + 1 + 3));
+
+ if (argc < 1)
+ die("BUG: shell command is empty");
+
+ nargv[nargc++] = "sh";
+ nargv[nargc++] = "-c";
+
+ if (argc < 2)
+ nargv[nargc++] = argv[0];
+ else {
+ struct strbuf arg0 = STRBUF_INIT;
+ strbuf_addf(&arg0, "%s \"$@\"", argv[0]);
+ nargv[nargc++] = strbuf_detach(&arg0, NULL);
+ }
+
+ for (argc = 0; argv[argc]; argc++)
+ nargv[nargc++] = argv[argc];
+ nargv[nargc] = NULL;
+
+ return nargv;
+}
+
+static int execv_shell_cmd(const char **argv)
+{
+ const char **nargv = prepare_shell_cmd(argv);
+ trace_argv_printf(nargv, "trace: exec:");
+ execvp(nargv[0], (char **)nargv);
+ free(nargv);
+ return -1;
+}
+
int start_command(struct child_process *cmd)
{
int need_in, need_out, need_err;
@@ -123,6 +163,8 @@ fail_pipe:
cmd->preexec_cb();
if (cmd->git_cmd) {
execv_git_cmd(cmd->argv);
+ } else if (cmd->use_shell) {
+ execv_shell_cmd(cmd->argv);
} else {
execvp(cmd->argv[0], (char *const*) cmd->argv);
}
@@ -179,6 +221,8 @@ fail_pipe:
if (cmd->git_cmd) {
cmd->argv = prepare_git_cmd(cmd->argv);
+ } else if (cmd->use_shell) {
+ cmd->argv = prepare_shell_cmd(cmd->argv);
}
cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, env);
@@ -297,6 +341,7 @@ static void prepare_run_command_v_opt(struct child_process *cmd,
cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
cmd->silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
+ cmd->use_shell = opt & RUN_USING_SHELL ? 1 : 0;
}
int run_command_v_opt(const char **argv, int opt)
diff --git a/run-command.h b/run-command.h
index fb34209..967ba8c 100644
--- a/run-command.h
+++ b/run-command.h
@@ -33,6 +33,7 @@ struct child_process {
unsigned git_cmd:1; /* if this is to be git sub-command */
unsigned silent_exec_failure:1;
unsigned stdout_to_stderr:1;
+ unsigned use_shell:1;
void (*preexec_cb)(void);
};
@@ -46,6 +47,7 @@ extern int run_hook(const char *index_file, const char *name, ...);
#define RUN_GIT_CMD 2 /*If this is to be git sub-command */
#define RUN_COMMAND_STDOUT_TO_STDERR 4
#define RUN_SILENT_EXEC_FAILURE 8
+#define RUN_USING_SHELL 16
int run_command_v_opt(const char **argv, int opt);
/*
--
1.6.6.65.g050d2.dirty
--
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