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Re: [PATCH] When exec'ing sub-commands, fall back on execvp (the PATH)

From
Johannes Schindelin <johannes.schindelin@gmx.de>
Date
Oct 20, 2007, 07:30 UTC
Message-ID
<Pine.LNX.4.64.0710200824270.25221@racer.site>
In-Reply-To
<20071020064459.GB2237@srparish.net>
Hi,
On Fri, 19 Oct 2007, Scott Parish wrote:
Show 49 quoted lines
> diff --git a/exec_cmd.c b/exec_cmd.c
> index 9b74ed2..674c9f3 100644
> --- a/exec_cmd.c
> +++ b/exec_cmd.c
> @@ -34,15 +34,15 @@ int execv_git_cmd(const char **argv)
>  {
>  	char git_command[PATH_MAX + 1];
>  	int i;
> +	int rc;
>  	const char *paths[] = { current_exec_path,
>  				getenv(EXEC_PATH_ENVIRONMENT),
>  				builtin_exec_path };
> +	const char *tmp;
> +	size_t len;
>  
>  	for (i = 0; i < ARRAY_SIZE(paths); ++i) {
> -		size_t len;
> -		int rc;
>  		const char *exec_dir = paths[i];
> -		const char *tmp;
>  
>  		if (!exec_dir || !*exec_dir) continue;
>  
> @@ -106,8 +106,26 @@ int execv_git_cmd(const char **argv)
>  
>  		argv[0] = tmp;
>  	}
> -	return -1;
>  
> +	rc = snprintf(git_command, sizeof(git_command), "git-%s", argv[0]);
> +	if (rc < 0 || rc >= sizeof(git_command) - len) {
> +		fprintf(stderr, "git: command name given is too long.\n");
> +		return -1;
> +	}
> +
> +	tmp = argv[0];
> +	argv[0] = git_command;
> +
> +	trace_argv_printf(argv, -1, "trace: exec:");
> +
> +	/* execve() can only ever return if it fails */
> +	execvp(git_command, (char **)argv);
> +
> +	trace_printf("trace: exec failed: %s\n", strerror(errno));
> +
> +	argv[0] = tmp;
> +
> +	return -1;
>  }

I am not sure that this is elegant enough: Something like this (completely untested) might be better:

diff --git a/exec_cmd.c b/exec_cmd.c
index 9b74ed2..c928f37 100644
--- a/exec_cmd.c
+++ b/exec_cmd.c
@@ -36,7 +36,8 @@ int execv_git_cmd(const char **argv)
 	int i;
 	const char *paths[] = { current_exec_path,
 				getenv(EXEC_PATH_ENVIRONMENT),
-				builtin_exec_path };
+				builtin_exec_path,
+				"" };
 
 	for (i = 0; i < ARRAY_SIZE(paths); ++i) {
 		size_t len;
@@ -44,9 +45,12 @@ int execv_git_cmd(const char **argv)
 		const char *exec_dir = paths[i];
 		const char *tmp;
 
-		if (!exec_dir || !*exec_dir) continue;
+		if (!exec_dir) continue;
 
-		if (*exec_dir != '/') {
+		if (!*exec_dir)
+			/* try PATH */
+			*git_command = '\0';
+		else if (*exec_dir != '/') {
 			if (!getcwd(git_command, sizeof(git_command))) {
 				fprintf(stderr, "git: cannot determine "
 					"current directory: %s\n",
@@ -81,7 +85,7 @@ int execv_git_cmd(const char **argv)
 
 		len = strlen(git_command);
 		rc = snprintf(git_command + len, sizeof(git_command) - len,
-			      "/git-%s", argv[0]);
+			      "%sgit-%s", *exec_dir ? "/" : "", argv[0]);
 		if (rc < 0 || rc >= sizeof(git_command) - len) {
 			fprintf(stderr,
 				"git: command name given is too long.\n");

Ciao,
Dscho
Previous: Scott Parish
Message 2 of 2 in “When exec'ing sub-commands, fall back on execvp (the PATH)”
  1. When exec'ing sub-commands, fall back on execvp (the PATH)Scott Parish, Oct 20, 2007
  2. Johannes SchindelinOct 20, 2007

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