use xgetcwd() to get the current directory or die

Convert several calls of getcwd() and die() to use xgetcwd() instead.
This way we get rid of fixed-size buffers (which can be too small
depending on the used file system) and gain consistent error messages.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/init-db.c

@@ -426,18 +426,20 @@ int init_db(const char *template_dir, unsigned int flags)
 
 static int guess_repository_type(const char *git_dir)
 {
-	char cwd[PATH_MAX];
 	const char *slash;
+	char *cwd;
+	int cwd_is_git_dir;
 
 	/*
 	 * "GIT_DIR=. git init" is always bare.
 	 * "GIT_DIR=`pwd` git init" too.
 	 */
 	if (!strcmp(".", git_dir))
 		return 1;
-	if (!getcwd(cwd, sizeof(cwd)))
-		die_errno(_("cannot tell cwd"));
-	if (!strcmp(git_dir, cwd))
+	cwd = xgetcwd();
+	cwd_is_git_dir = !strcmp(git_dir, cwd);
+	free(cwd);
+	if (cwd_is_git_dir)
 		return 1;
 	/*
 	 * "GIT_DIR=.git or GIT_DIR=something/.git is usually not.
@@ -572,11 +574,8 @@ int cmd_init_db(int argc, const char **argv, const char *prefix)
 			git_work_tree_cfg = xstrdup(real_path(rel));
 			free(rel);
 		}
-		if (!git_work_tree_cfg) {
-			git_work_tree_cfg = xcalloc(PATH_MAX, 1);
-			if (!getcwd(git_work_tree_cfg, PATH_MAX))
-				die_errno (_("Cannot access current working directory"));
-		}
+		if (!git_work_tree_cfg)
+			git_work_tree_cfg = xgetcwd();
 		if (work_tree)
 			set_git_work_tree(real_path(work_tree));
 		else

builtin/rev-parse.c

@@ -734,7 +734,7 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix)
 			}
 			if (!strcmp(arg, "--git-dir")) {
 				const char *gitdir = getenv(GIT_DIR_ENVIRONMENT);
-				static char cwd[PATH_MAX];
+				char *cwd;
 				int len;
 				if (gitdir) {
 					puts(gitdir);
@@ -744,10 +744,10 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix)
 					puts(".git");
 					continue;
 				}
-				if (!getcwd(cwd, PATH_MAX))
-					die_errno("unable to get current working directory");
+				cwd = xgetcwd();
 				len = strlen(cwd);
 				printf("%s%s.git\n", cwd, len && cwd[len-1] != '/' ? "/" : "");
+				free(cwd);
 				continue;
 			}
 			if (!strcmp(arg, "--resolve-git-dir")) {

dir.c

@@ -1500,12 +1500,16 @@ int dir_inside_of(const char *subdir, const char *dir)
 
 int is_inside_dir(const char *dir)
 {
-	char cwd[PATH_MAX];
+	char *cwd;
+	int rc;
+
 	if (!dir)
 		return 0;
-	if (!getcwd(cwd, sizeof(cwd)))
-		die_errno("can't find the current directory");
-	return dir_inside_of(cwd, dir) >= 0;
+
+	cwd = xgetcwd();
+	rc = (dir_inside_of(cwd, dir) >= 0);
+	free(cwd);
+	return rc;
 }
 
 int is_empty_dir(const char *path)

setup.c

@@ -434,16 +434,16 @@ static const char *setup_explicit_git_dir(const char *gitdirenv,
 		if (is_absolute_path(git_work_tree_cfg))
 			set_git_work_tree(git_work_tree_cfg);
 		else {
-			char core_worktree[PATH_MAX];
+			char *core_worktree;
 			if (chdir(gitdirenv))
 				die_errno("Could not chdir to '%s'", gitdirenv);
 			if (chdir(git_work_tree_cfg))
 				die_errno("Could not chdir to '%s'", git_work_tree_cfg);
-			if (!getcwd(core_worktree, PATH_MAX))
-				die_errno("Could not get directory '%s'", git_work_tree_cfg);
+			core_worktree = xgetcwd();
 			if (chdir(cwd->buf))
 				die_errno("Could not come back to cwd");
 			set_git_work_tree(core_worktree);
+			free(core_worktree);
 		}
 	}
 	else if (!git_env_bool(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, 1)) {

trace.c

@@ -158,13 +158,12 @@ void trace_repo_setup(const char *prefix)
 {
 	static const char *key = "GIT_TRACE_SETUP";
 	const char *git_work_tree;
-	char cwd[PATH_MAX];
+	char *cwd;
 
 	if (!trace_want(key))
 		return;
 
-	if (!getcwd(cwd, PATH_MAX))
-		die("Unable to get current working directory");
+	cwd = xgetcwd();
 
 	if (!(git_work_tree = get_git_work_tree()))
 		git_work_tree = "(null)";
@@ -176,6 +175,8 @@ void trace_repo_setup(const char *prefix)
 	trace_printf_key(key, "setup: worktree: %s\n", quote_crnl(git_work_tree));
 	trace_printf_key(key, "setup: cwd: %s\n", quote_crnl(cwd));
 	trace_printf_key(key, "setup: prefix: %s\n", quote_crnl(prefix));
+
+	free(cwd);
 }
 
 int trace_want(const char *key)