1 files changed, 165 insertions, 0 deletions
diff --git a/exec-cmd.c b/exec-cmd.c
new file mode 100644
index 0000000000..8a8261746a
--- /dev/null
+++ b/exec-cmd.c
@@ -0,0 +1,165 @@
+#include "cache.h"
+#include "exec-cmd.h"
+#include "quote.h"
+#include "argv-array.h"
+#define MAX_ARGS	32
+
+static const char *argv_exec_path;
+
+#ifdef RUNTIME_PREFIX
+static const char *argv0_path;
+
+static const char *system_prefix(void)
+{
+	static const char *prefix;
+
+	assert(argv0_path);
+	assert(is_absolute_path(argv0_path));
+
+	if (!prefix &&
+	    !(prefix = strip_path_suffix(argv0_path, GIT_EXEC_PATH)) &&
+	    !(prefix = strip_path_suffix(argv0_path, BINDIR)) &&
+	    !(prefix = strip_path_suffix(argv0_path, "git"))) {
+		prefix = PREFIX;
+		trace_printf("RUNTIME_PREFIX requested, "
+				"but prefix computation failed.  "
+				"Using static fallback '%s'.\n", prefix);
+	}
+	return prefix;
+}
+
+void git_extract_argv0_path(const char *argv0)
+{
+	const char *slash;
+
+	if (!argv0 || !*argv0)
+		return;
+
+	slash = find_last_dir_sep(argv0);
+
+	if (slash)
+		argv0_path = xstrndup(argv0, slash - argv0);
+}
+
+#else
+
+static const char *system_prefix(void)
+{
+	return PREFIX;
+}
+
+void git_extract_argv0_path(const char *argv0)
+{
+}
+
+#endif /* RUNTIME_PREFIX */
+
+char *system_path(const char *path)
+{
+	struct strbuf d = STRBUF_INIT;
+
+	if (is_absolute_path(path))
+		return xstrdup(path);
+
+	strbuf_addf(&d, "%s/%s", system_prefix(), path);
+	return strbuf_detach(&d, NULL);
+}
+
+void git_set_argv_exec_path(const char *exec_path)
+{
+	argv_exec_path = exec_path;
+	/*
+	 * Propagate this setting to external programs.
+	 */
+	setenv(EXEC_PATH_ENVIRONMENT, exec_path, 1);
+}
+
+
+/* Returns the highest-priority, location to look for git programs. */
+const char *git_exec_path(void)
+{
+	static char *cached_exec_path;
+
+	if (argv_exec_path)
+		return argv_exec_path;
+
+	if (!cached_exec_path) {
+		const char *env = getenv(EXEC_PATH_ENVIRONMENT);
+		if (env && *env)
+			cached_exec_path = xstrdup(env);
+		else
+			cached_exec_path = system_path(GIT_EXEC_PATH);
+	}
+	return cached_exec_path;
+}
+
+static void add_path(struct strbuf *out, const char *path)
+{
+	if (path && *path) {
+		strbuf_add_absolute_path(out, path);
+		strbuf_addch(out, PATH_SEP);
+	}
+}
+
+void setup_path(void)
+{
+	const char *old_path = getenv("PATH");
+	struct strbuf new_path = STRBUF_INIT;
+
+	add_path(&new_path, git_exec_path());
+
+	if (old_path)
+		strbuf_addstr(&new_path, old_path);
+	else
+		strbuf_addstr(&new_path, _PATH_DEFPATH);
+
+	setenv("PATH", new_path.buf, 1);
+
+	strbuf_release(&new_path);
+}
+
+const char **prepare_git_cmd(struct argv_array *out, const char **argv)
+{
+	argv_array_push(out, "git");
+	argv_array_pushv(out, argv);
+	return out->argv;
+}
+
+int execv_git_cmd(const char **argv) {
+	struct argv_array nargv = ARGV_ARRAY_INIT;
+
+	prepare_git_cmd(&nargv, argv);
+	trace_argv_printf(nargv.argv, "trace: exec:");
+
+	/* execvp() can only ever return if it fails */
+	sane_execvp("git", (char **)nargv.argv);
+
+	trace_printf("trace: exec failed: %s\n", strerror(errno));
+
+	argv_array_clear(&nargv);
+	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);
+}