Re: [PATCH 1/3] C implementation of the 'git' program, take two.

[Junio C Hamano <junkio@cox.net>]

exon@op5.se (Andreas Ericsson) writes:

> This patch provides a C implementation of the 'git' program and
> introduces support for putting the git-* commands in a directory
> of their own.

Very nice, thanks.  Two questions and a half.

> +static void prepend_to_path(const char *dir, int len)
> +{
> +	char *path, *old_path = getenv("PATH");
> +	int path_len = len;
> +
> +	if (!old_path)
> +		old_path = "/bin:/usr/bin:.";

This is to cover strange case and probably would not matter in
practice, but perhaps without current directory?

> +int main(int argc, char **argv, char **envp)
> +{
> +	char git_command[PATH_MAX + 1];
> +	char wd[PATH_MAX + 1];
> +	int i, len, show_help = 0;
> +	char *exec_path = getenv("GIT_EXEC_PATH");
> +
> +	getcwd(wd, PATH_MAX);
> +...
> +	/* allow relative paths, but run with exact */
> +	if (chdir(exec_path)) {
> +		printf("git: '%s': %s\n", exec_path, strerror(errno));
> +		exit (1);
> +	}
> +
> +	getcwd(git_command, sizeof(git_command));
> +	chdir(wd);

Can we always come back from where we started?

> +
> +	len = strlen(git_command);
> +	prepend_to_path(git_command, len);
> +
> +	strncat(&git_command[len], "/git-", sizeof(git_command) - len);
> +	len += 5;
> +	strncat(&git_command[len], argv[i], sizeof(git_command) - len);
> +
> +	if (access(git_command, X_OK))
> +		usage(exec_path, "'%s' is not a git-command", argv[i]);
> +
> +	/* execve() can only ever return if it fails */
> +	execve(git_command, &argv[i], envp);

Shell version for Cygwin seems to do ".exe" at the end --- does
it matter?