1 files changed, 363 insertions, 0 deletions
diff --git a/src/libgit2/sysdir.c b/src/libgit2/sysdir.c
new file mode 100644
index 000000000..450cb509b
--- /dev/null
+++ b/src/libgit2/sysdir.c
@@ -0,0 +1,363 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+#include "sysdir.h"
+
+#include "runtime.h"
+#include "str.h"
+#include "fs_path.h"
+#include <ctype.h>
+#if GIT_WIN32
+#include "win32/findfile.h"
+#else
+#include <unistd.h>
+#include <pwd.h>
+#endif
+
+static int git_sysdir_guess_programdata_dirs(git_str *out)
+{
+#ifdef GIT_WIN32
+	return git_win32__find_programdata_dirs(out);
+#else
+	git_str_clear(out);
+	return 0;
+#endif
+}
+
+static int git_sysdir_guess_system_dirs(git_str *out)
+{
+#ifdef GIT_WIN32
+	return git_win32__find_system_dirs(out, "etc");
+#else
+	return git_str_sets(out, "/etc");
+#endif
+}
+
+#ifndef GIT_WIN32
+static int get_passwd_home(git_str *out, uid_t uid)
+{
+	struct passwd pwd, *pwdptr;
+	char *buf = NULL;
+	long buflen;
+	int error;
+
+	GIT_ASSERT_ARG(out);
+
+	if ((buflen = sysconf(_SC_GETPW_R_SIZE_MAX)) == -1)
+		buflen = 1024;
+
+	do {
+		buf = git__realloc(buf, buflen);
+		error = getpwuid_r(uid, &pwd, buf, buflen, &pwdptr);
+		buflen *= 2;
+	} while (error == ERANGE && buflen <= 8192);
+
+	if (error) {
+		git_error_set(GIT_ERROR_OS, "failed to get passwd entry");
+		goto out;
+	}
+
+	if (!pwdptr) {
+		git_error_set(GIT_ERROR_OS, "no passwd entry found for user");
+		goto out;
+	}
+
+	if ((error = git_str_puts(out, pwdptr->pw_dir)) < 0)
+		goto out;
+
+out:
+	git__free(buf);
+	return error;
+}
+#endif
+
+static int git_sysdir_guess_global_dirs(git_str *out)
+{
+#ifdef GIT_WIN32
+	return git_win32__find_global_dirs(out);
+#else
+	int error;
+	uid_t uid, euid;
+	const char *sandbox_id;
+
+	uid = getuid();
+	euid = geteuid();
+
+	/**
+	 * If APP_SANDBOX_CONTAINER_ID is set, we are running in a
+	 * sandboxed environment on macOS.
+	 */
+	sandbox_id = getenv("APP_SANDBOX_CONTAINER_ID");
+
+	/*
+	 * In case we are running setuid, use the configuration
+	 * of the effective user.
+	 *
+	 * If we are running in a sandboxed environment on macOS,
+	 * we have to get the HOME dir from the password entry file.
+	 */
+	if (!sandbox_id && uid == euid)
+	    error = git__getenv(out, "HOME");
+	else
+	    error = get_passwd_home(out, euid);
+
+	if (error == GIT_ENOTFOUND) {
+		git_error_clear();
+		error = 0;
+	}
+
+	return error;
+#endif
+}
+
+static int git_sysdir_guess_xdg_dirs(git_str *out)
+{
+#ifdef GIT_WIN32
+	return git_win32__find_xdg_dirs(out);
+#else
+	git_str env = GIT_STR_INIT;
+	int error;
+	uid_t uid, euid;
+
+	uid = getuid();
+	euid = geteuid();
+
+	/*
+	 * In case we are running setuid, only look up passwd
+	 * directory of the effective user.
+	 */
+	if (uid == euid) {
+		if ((error = git__getenv(&env, "XDG_CONFIG_HOME")) == 0)
+			error = git_str_joinpath(out, env.ptr, "git");
+
+		if (error == GIT_ENOTFOUND && (error = git__getenv(&env, "HOME")) == 0)
+			error = git_str_joinpath(out, env.ptr, ".config/git");
+	} else {
+		if ((error = get_passwd_home(&env, euid)) == 0)
+			error = git_str_joinpath(out, env.ptr, ".config/git");
+	}
+
+	if (error == GIT_ENOTFOUND) {
+		git_error_clear();
+		error = 0;
+	}
+
+	git_str_dispose(&env);
+	return error;
+#endif
+}
+
+static int git_sysdir_guess_template_dirs(git_str *out)
+{
+#ifdef GIT_WIN32
+	return git_win32__find_system_dirs(out, "share/git-core/templates");
+#else
+	return git_str_sets(out, "/usr/share/git-core/templates");
+#endif
+}
+
+struct git_sysdir__dir {
+	git_str buf;
+	int (*guess)(git_str *out);
+};
+
+static struct git_sysdir__dir git_sysdir__dirs[] = {
+	{ GIT_STR_INIT, git_sysdir_guess_system_dirs },
+	{ GIT_STR_INIT, git_sysdir_guess_global_dirs },
+	{ GIT_STR_INIT, git_sysdir_guess_xdg_dirs },
+	{ GIT_STR_INIT, git_sysdir_guess_programdata_dirs },
+	{ GIT_STR_INIT, git_sysdir_guess_template_dirs },
+};
+
+static void git_sysdir_global_shutdown(void)
+{
+	size_t i;
+
+	for (i = 0; i < ARRAY_SIZE(git_sysdir__dirs); ++i)
+		git_str_dispose(&git_sysdir__dirs[i].buf);
+}
+
+int git_sysdir_global_init(void)
+{
+	size_t i;
+	int error = 0;
+
+	for (i = 0; !error && i < ARRAY_SIZE(git_sysdir__dirs); i++)
+		error = git_sysdir__dirs[i].guess(&git_sysdir__dirs[i].buf);
+
+	if (error)
+		return error;
+
+	return git_runtime_shutdown_register(git_sysdir_global_shutdown);
+}
+
+int git_sysdir_reset(void)
+{
+	size_t i;
+	int error = 0;
+
+	for (i = 0; !error && i < ARRAY_SIZE(git_sysdir__dirs); ++i) {
+		git_str_dispose(&git_sysdir__dirs[i].buf);
+		error = git_sysdir__dirs[i].guess(&git_sysdir__dirs[i].buf);
+	}
+
+	return error;
+}
+
+static int git_sysdir_check_selector(git_sysdir_t which)
+{
+	if (which < ARRAY_SIZE(git_sysdir__dirs))
+		return 0;
+
+	git_error_set(GIT_ERROR_INVALID, "config directory selector out of range");
+	return -1;
+}
+
+
+int git_sysdir_get(const git_str **out, git_sysdir_t which)
+{
+	GIT_ASSERT_ARG(out);
+
+	*out = NULL;
+
+	GIT_ERROR_CHECK_ERROR(git_sysdir_check_selector(which));
+
+	*out = &git_sysdir__dirs[which].buf;
+	return 0;
+}
+
+#define PATH_MAGIC "$PATH"
+
+int git_sysdir_set(git_sysdir_t which, const char *search_path)
+{
+	const char *expand_path = NULL;
+	git_str merge = GIT_STR_INIT;
+
+	GIT_ERROR_CHECK_ERROR(git_sysdir_check_selector(which));
+
+	if (search_path != NULL)
+		expand_path = strstr(search_path, PATH_MAGIC);
+
+	/* reset the default if this path has been cleared */
+	if (!search_path)
+		git_sysdir__dirs[which].guess(&git_sysdir__dirs[which].buf);
+
+	/* if $PATH is not referenced, then just set the path */
+	if (!expand_path) {
+		if (search_path)
+			git_str_sets(&git_sysdir__dirs[which].buf, search_path);
+
+		goto done;
+	}
+
+	/* otherwise set to join(before $PATH, old value, after $PATH) */
+	if (expand_path > search_path)
+		git_str_set(&merge, search_path, expand_path - search_path);
+
+	if (git_str_len(&git_sysdir__dirs[which].buf))
+		git_str_join(&merge, GIT_PATH_LIST_SEPARATOR,
+			merge.ptr, git_sysdir__dirs[which].buf.ptr);
+
+	expand_path += strlen(PATH_MAGIC);
+	if (*expand_path)
+		git_str_join(&merge, GIT_PATH_LIST_SEPARATOR, merge.ptr, expand_path);
+
+	git_str_swap(&git_sysdir__dirs[which].buf, &merge);
+	git_str_dispose(&merge);
+
+done:
+	if (git_str_oom(&git_sysdir__dirs[which].buf))
+		return -1;
+
+	return 0;
+}
+
+static int git_sysdir_find_in_dirlist(
+	git_str *path,
+	const char *name,
+	git_sysdir_t which,
+	const char *label)
+{
+	size_t len;
+	const char *scan, *next = NULL;
+	const git_str *syspath;
+
+	GIT_ERROR_CHECK_ERROR(git_sysdir_get(&syspath, which));
+	if (!syspath || !git_str_len(syspath))
+		goto done;
+
+	for (scan = git_str_cstr(syspath); scan; scan = next) {
+		/* find unescaped separator or end of string */
+		for (next = scan; *next; ++next) {
+			if (*next == GIT_PATH_LIST_SEPARATOR &&
+				(next <= scan || next[-1] != '\\'))
+				break;
+		}
+
+		len = (size_t)(next - scan);
+		next = (*next ? next + 1 : NULL);
+		if (!len)
+			continue;
+
+		GIT_ERROR_CHECK_ERROR(git_str_set(path, scan, len));
+		if (name)
+			GIT_ERROR_CHECK_ERROR(git_str_joinpath(path, path->ptr, name));
+
+		if (git_fs_path_exists(path->ptr))
+			return 0;
+	}
+
+done:
+	if (name)
+		git_error_set(GIT_ERROR_OS, "the %s file '%s' doesn't exist", label, name);
+	else
+		git_error_set(GIT_ERROR_OS, "the %s directory doesn't exist", label);
+	git_str_dispose(path);
+	return GIT_ENOTFOUND;
+}
+
+int git_sysdir_find_system_file(git_str *path, const char *filename)
+{
+	return git_sysdir_find_in_dirlist(
+		path, filename, GIT_SYSDIR_SYSTEM, "system");
+}
+
+int git_sysdir_find_global_file(git_str *path, const char *filename)
+{
+	return git_sysdir_find_in_dirlist(
+		path, filename, GIT_SYSDIR_GLOBAL, "global");
+}
+
+int git_sysdir_find_xdg_file(git_str *path, const char *filename)
+{
+	return git_sysdir_find_in_dirlist(
+		path, filename, GIT_SYSDIR_XDG, "global/xdg");
+}
+
+int git_sysdir_find_programdata_file(git_str *path, const char *filename)
+{
+	return git_sysdir_find_in_dirlist(
+		path, filename, GIT_SYSDIR_PROGRAMDATA, "ProgramData");
+}
+
+int git_sysdir_find_template_dir(git_str *path)
+{
+	return git_sysdir_find_in_dirlist(
+		path, NULL, GIT_SYSDIR_TEMPLATE, "template");
+}
+
+int git_sysdir_expand_global_file(git_str *path, const char *filename)
+{
+	int error;
+
+	if ((error = git_sysdir_find_global_file(path, NULL)) == 0) {
+		if (filename)
+			error = git_str_joinpath(path, path->ptr, filename);
+	}
+
+	return error;
+}