path: root/run-command.c
diff options
authorJeff King <>2009-01-28 07:35:33 (GMT)
committerJunio C Hamano <>2009-01-28 22:08:57 (GMT)
commit45c0961c87884a04517b65c0acc6aedeeae2d0c8 (patch)
tree1758b488113a6654b63e8829682f745c7a855fb7 /run-command.c
parentf172f334fde49ce29d0afa21749bf85463a2db9a (diff)
run_command(): handle missing command errors more gracefully
When run_command() was asked to run a non-existant command, its behavior varied depending on the platform: - on POSIX systems, we would fork, and then after the execvp call failed, we could call die(), which prints a message to stderr and exits with code 128. - on Windows, we do a PATH lookup, realize the program isn't there, and then return ERR_RUN_COMMAND_FORK The goal of this patch is to make it clear to callers that the specific error was a missing command. To do this, we will return the error code ERR_RUN_COMMAND_EXEC, which is already defined in run-command.h, checked for in several places, but never actually gets set. The new behavior is: - on POSIX systems, we exit the forked process with code 127 (the same as the shell uses to report missing commands). The parent process recognizes this code and returns an EXEC error. The stderr message is silenced, since the caller may be speculatively trying to run a command. Instead, we use trace_printf so that somebody interested in debugging can see the error that occured. - on Windows, we check errno, which is already set correctly by mingw_spawnvpe, and report an EXEC error instead of a FORK error Thus it is safe to speculatively run a command: int r = run_command_v_opt(argv, 0); if (r == -ERR_RUN_COMMAND_EXEC) /* oops, it wasn't found; try something else */ else /* we failed for some other reason, error is in r */ Signed-off-by: Jeff King <> Signed-off-by: Junio C Hamano <>
Diffstat (limited to 'run-command.c')
1 files changed, 14 insertions, 4 deletions
diff --git a/run-command.c b/run-command.c
index c90cdc5..44fccc9 100644
--- a/run-command.c
+++ b/run-command.c
@@ -118,7 +118,9 @@ int start_command(struct child_process *cmd)
} else {
execvp(cmd->argv[0], (char *const*) cmd->argv);
- die("exec %s failed.", cmd->argv[0]);
+ trace_printf("trace: exec '%s' failed: %s\n", cmd->argv[0],
+ strerror(errno));
+ exit(127);
int s0 = -1, s1 = -1, s2 = -1; /* backups of stdin, stdout, stderr */
@@ -187,6 +189,7 @@ int start_command(struct child_process *cmd)
if (cmd->pid < 0) {
+ int err = errno;
if (need_in)
else if (cmd->in)
@@ -197,7 +200,9 @@ int start_command(struct child_process *cmd)
if (need_err)
+ return err == ENOENT ?
if (need_in)
@@ -236,9 +241,14 @@ static int wait_or_whine(pid_t pid)
if (!WIFEXITED(status))
code = WEXITSTATUS(status);
- if (code)
+ switch (code) {
+ case 127:
+ case 0:
+ return 0;
+ default:
return -code;
- return 0;
+ }