1 files changed, 135 insertions, 0 deletions
diff --git a/exec_cmd.c b/exec_cmd.c
new file mode 100644
index 0000000..9b74ed2
--- /dev/null
+++ b/exec_cmd.c
@@ -0,0 +1,135 @@
+#include "cache.h"
+#include "exec_cmd.h"
+#include "quote.h"
+#define MAX_ARGS	32
+
+extern char **environ;
+static const char *builtin_exec_path = GIT_EXEC_PATH;
+static const char *current_exec_path;
+
+void git_set_exec_path(const char *exec_path)
+{
+	current_exec_path = exec_path;
+}
+
+
+/* Returns the highest-priority, location to look for git programs. */
+const char *git_exec_path(void)
+{
+	const char *env;
+
+	if (current_exec_path)
+		return current_exec_path;
+
+	env = getenv(EXEC_PATH_ENVIRONMENT);
+	if (env && *env) {
+		return env;
+	}
+
+	return builtin_exec_path;
+}
+
+
+int execv_git_cmd(const char **argv)
+{
+	char git_command[PATH_MAX + 1];
+	int i;
+	const char *paths[] = { current_exec_path,
+				getenv(EXEC_PATH_ENVIRONMENT),
+				builtin_exec_path };
+
+	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;
+
+		if (*exec_dir != '/') {
+			if (!getcwd(git_command, sizeof(git_command))) {
+				fprintf(stderr, "git: cannot determine "
+					"current directory: %s\n",
+					strerror(errno));
+				break;
+			}
+			len = strlen(git_command);
+
+			/* Trivial cleanup */
+			while (!prefixcmp(exec_dir, "./")) {
+				exec_dir += 2;
+				while (*exec_dir == '/')
+					exec_dir++;
+			}
+
+			rc = snprintf(git_command + len,
+				      sizeof(git_command) - len, "/%s",
+				      exec_dir);
+			if (rc < 0 || rc >= sizeof(git_command) - len) {
+				fprintf(stderr, "git: command name given "
+					"is too long.\n");
+				break;
+			}
+		} else {
+			if (strlen(exec_dir) + 1 > sizeof(git_command)) {
+				fprintf(stderr, "git: command name given "
+					"is too long.\n");
+				break;
+			}
+			strcpy(git_command, exec_dir);
+		}
+
+		len = strlen(git_command);
+		rc = snprintf(git_command + len, sizeof(git_command) - len,
+			      "/git-%s", argv[0]);
+		if (rc < 0 || rc >= sizeof(git_command) - len) {
+			fprintf(stderr,
+				"git: command name given is too long.\n");
+			break;
+		}
+
+		/* argv[0] must be the git command, but the argv array
+		 * belongs to the caller, and my be reused in
+		 * subsequent loop iterations. Save argv[0] and
+		 * restore it on error.
+		 */
+
+		tmp = argv[0];
+		argv[0] = git_command;
+
+		trace_argv_printf(argv, -1, "trace: exec:");
+
+		/* execve() can only ever return if it fails */
+		execve(git_command, (char **)argv, environ);
+
+		trace_printf("trace: exec failed: %s\n", strerror(errno));
+
+		argv[0] = tmp;
+	}
+	return -1;
+
+}
+
+
+int execl_git_cmd(const char *cmd,...)
+{
+	int argc;
+	const char *argv[MAX_ARGS + 1];
+	const char *arg;
+	va_list param;
+
+	va_start(param, cmd);
+	argv[0] = cmd;
+	argc = 1;
+	while (argc < MAX_ARGS) {
+		arg = argv[argc++] = va_arg(param, char *);
+		if (!arg)
+			break;
+	}
+	va_end(param);
+	if (MAX_ARGS <= argc)
+		return error("too many args to run %s", cmd);
+
+	argv[argc] = NULL;
+	return execv_git_cmd(argv);
+}