Merge branch 'rs/strbuf-getcwd'

Reduce the use of fixed sized buffer passed to getcwd() calls
by introducing xgetcwd() helper.

* rs/strbuf-getcwd:
  use strbuf_add_absolute_path() to add absolute paths
  abspath: convert absolute_path() to strbuf
  use xgetcwd() to set $GIT_DIR
  use xgetcwd() to get the current directory or die
  wrapper: add xgetcwd()
  abspath: convert real_path_internal() to strbuf
  abspath: use strbuf_getcwd() to remember original working directory
  setup: convert setup_git_directory_gently_1 et al. to strbuf
  unix-sockets: use strbuf_getcwd()
  strbuf: add strbuf_getcwd()

Author: gitster

Documentation/technical/api-strbuf.txt

@@ -307,6 +307,16 @@ same behaviour as well.
 	use it unless you need the correct position in the file
 	descriptor.
 
+`strbuf_getcwd`::
+
+	Set the buffer to the path of the current working directory.
+
+`strbuf_add_absolute_path`
+
+	Add a path to a buffer, converting a relative path to an
+	absolute one in the process.  Symbolic links are not
+	resolved.
+
 `stripspace`::
 
 	Strip whitespace from a buffer. The second parameter controls if

abspath.c

@@ -33,24 +33,22 @@ int is_directory(const char *path)
  */
 static const char *real_path_internal(const char *path, int die_on_error)
 {
-	static char bufs[2][PATH_MAX + 1], *buf = bufs[0], *next_buf = bufs[1];
+	static struct strbuf sb = STRBUF_INIT;
 	char *retval = NULL;
 
 	/*
 	 * If we have to temporarily chdir(), store the original CWD
 	 * here so that we can chdir() back to it at the end of the
 	 * function:
 	 */
-	char cwd[1024] = "";
-
-	int buf_index = 1;
+	struct strbuf cwd = STRBUF_INIT;
 
 	int depth = MAXDEPTH;
 	char *last_elem = NULL;
 	struct stat st;
 
 	/* We've already done it */
-	if (path == buf || path == next_buf)
+	if (path == sb.buf)
 		return path;
 
 	if (!*path) {
@@ -60,90 +58,74 @@ static const char *real_path_internal(const char *path, int die_on_error)
 			goto error_out;
 	}
 
-	if (strlcpy(buf, path, PATH_MAX) >= PATH_MAX) {
-		if (die_on_error)
-			die("Too long path: %.*s", 60, path);
-		else
-			goto error_out;
-	}
+	strbuf_reset(&sb);
+	strbuf_addstr(&sb, path);
 
 	while (depth--) {
-		if (!is_directory(buf)) {
-			char *last_slash = find_last_dir_sep(buf);
+		if (!is_directory(sb.buf)) {
+			char *last_slash = find_last_dir_sep(sb.buf);
 			if (last_slash) {
 				last_elem = xstrdup(last_slash + 1);
-				last_slash[1] = '\0';
+				strbuf_setlen(&sb, last_slash - sb.buf + 1);
 			} else {
-				last_elem = xstrdup(buf);
-				*buf = '\0';
+				last_elem = xmemdupz(sb.buf, sb.len);
+				strbuf_reset(&sb);
 			}
 		}
 
-		if (*buf) {
-			if (!*cwd && !getcwd(cwd, sizeof(cwd))) {
+		if (sb.len) {
+			if (!cwd.len && strbuf_getcwd(&cwd)) {
 				if (die_on_error)
 					die_errno("Could not get current working directory");
 				else
 					goto error_out;
 			}
 
-			if (chdir(buf)) {
+			if (chdir(sb.buf)) {
 				if (die_on_error)
-					die_errno("Could not switch to '%s'", buf);
+					die_errno("Could not switch to '%s'",
+						  sb.buf);
 				else
 					goto error_out;
 			}
 		}
-		if (!getcwd(buf, PATH_MAX)) {
+		if (strbuf_getcwd(&sb)) {
 			if (die_on_error)
 				die_errno("Could not get current working directory");
 			else
 				goto error_out;
 		}
 
 		if (last_elem) {
-			size_t len = strlen(buf);
-			if (len + strlen(last_elem) + 2 > PATH_MAX) {
-				if (die_on_error)
-					die("Too long path name: '%s/%s'",
-					    buf, last_elem);
-				else
-					goto error_out;
-			}
-			if (len && !is_dir_sep(buf[len - 1]))
-				buf[len++] = '/';
-			strcpy(buf + len, last_elem);
+			if (sb.len && !is_dir_sep(sb.buf[sb.len - 1]))
+				strbuf_addch(&sb, '/');
+			strbuf_addstr(&sb, last_elem);
 			free(last_elem);
 			last_elem = NULL;
 		}
 
-		if (!lstat(buf, &st) && S_ISLNK(st.st_mode)) {
-			ssize_t len = readlink(buf, next_buf, PATH_MAX);
+		if (!lstat(sb.buf, &st) && S_ISLNK(st.st_mode)) {
+			struct strbuf next_sb = STRBUF_INIT;
+			ssize_t len = strbuf_readlink(&next_sb, sb.buf, 0);
 			if (len < 0) {
 				if (die_on_error)
-					die_errno("Invalid symlink '%s'", buf);
-				else
-					goto error_out;
-			}
-			if (PATH_MAX <= len) {
-				if (die_on_error)
-					die("symbolic link too long: %s", buf);
+					die_errno("Invalid symlink '%s'",
+						  sb.buf);
 				else
 					goto error_out;
 			}
-			next_buf[len] = '\0';
-			buf = next_buf;
-			buf_index = 1 - buf_index;
-			next_buf = bufs[buf_index];
+			strbuf_swap(&sb, &next_sb);
+			strbuf_release(&next_sb);
 		} else
 			break;
 	}
 
-	retval = buf;
+	retval = sb.buf;
 error_out:
 	free(last_elem);
-	if (*cwd && chdir(cwd))
-		die_errno("Could not change back to '%s'", cwd);
+	if (cwd.len && chdir(cwd.buf))
+		die_errno("Could not change back to '%s'", cwd.buf);
+	strbuf_release(&cwd);
 
 	return retval;
 }
@@ -158,54 +140,16 @@ const char *real_path_if_valid(const char *path)
 	return real_path_internal(path, 0);
 }
 
-static const char *get_pwd_cwd(void)
-{
-	static char cwd[PATH_MAX + 1];
-	char *pwd;
-	struct stat cwd_stat, pwd_stat;
-	if (getcwd(cwd, PATH_MAX) == NULL)
-		return NULL;
-	pwd = getenv("PWD");
-	if (pwd && strcmp(pwd, cwd)) {
-		stat(cwd, &cwd_stat);
-		if ((cwd_stat.st_dev || cwd_stat.st_ino) &&
-		    !stat(pwd, &pwd_stat) &&
-		    pwd_stat.st_dev == cwd_stat.st_dev &&
-		    pwd_stat.st_ino == cwd_stat.st_ino) {
-			strlcpy(cwd, pwd, PATH_MAX);
-		}
-	}
-	return cwd;
-}
-
 /*
  * Use this to get an absolute path from a relative one. If you want
  * to resolve links, you should use real_path.
- *
- * If the path is already absolute, then return path. As the user is
- * never meant to free the return value, we're safe.
  */
 const char *absolute_path(const char *path)
 {
-	static char buf[PATH_MAX + 1];
-
-	if (!*path) {
-		die("The empty string is not a valid path");
-	} else if (is_absolute_path(path)) {
-		if (strlcpy(buf, path, PATH_MAX) >= PATH_MAX)
-			die("Too long path: %.*s", 60, path);
-	} else {
-		size_t len;
-		const char *fmt;
-		const char *cwd = get_pwd_cwd();
-		if (!cwd)
-			die_errno("Cannot determine the current working directory");
-		len = strlen(cwd);
-		fmt = (len > 0 && is_dir_sep(cwd[len - 1])) ? "%s%s" : "%s/%s";
-		if (snprintf(buf, PATH_MAX, fmt, cwd, path) >= PATH_MAX)
-			die("Too long path: %.*s", 60, path);
-	}
-	return buf;
+	static struct strbuf sb = STRBUF_INIT;
+	strbuf_reset(&sb);
+	strbuf_add_absolute_path(&sb, path);
+	return sb.buf;
 }
 
 /*

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.
@@ -535,10 +537,9 @@ int cmd_init_db(int argc, const char **argv, const char *prefix)
 		usage(init_db_usage[0]);
 	}
 	if (is_bare_repository_cfg == 1) {
-		static char git_dir[PATH_MAX+1];
-
-		setenv(GIT_DIR_ENVIRONMENT,
-			getcwd(git_dir, sizeof(git_dir)), argc > 0);
+		char *cwd = xgetcwd();
+		setenv(GIT_DIR_ENVIRONMENT, cwd, argc > 0);
+		free(cwd);
 	}
 
 	if (init_shared_repository != -1)
@@ -572,11 +573,8 @@ 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(work_tree);
 		else

builtin/rev-parse.c

@@ -736,7 +736,7 @@ 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);
@@ -746,10 +746,10 @@ 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

@@ -1507,12 +1507,16 @@ 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)

exec_cmd.c

@@ -86,11 +86,7 @@ const char *git_exec_path(void)
 static void add_path(struct strbuf *out, const char *path)
 {
 	if (path && *path) {
-		if (is_absolute_path(path))
-			strbuf_addstr(out, path);
-		else
-			strbuf_addstr(out, absolute_path(path));
-
+		strbuf_add_absolute_path(out, path);
 		strbuf_addch(out, PATH_SEP);
 	}
 }

git-compat-util.h

@@ -607,6 +607,7 @@ extern int xmkstemp(char *template);
 extern int xmkstemp_mode(char *template, int mode);
 extern int odb_mkstemp(char *template, size_t limit, const char *pattern);
 extern int odb_pack_keep(char *name, size_t namesz, const unsigned char *sha1);
+extern char *xgetcwd(void);
 
 static inline size_t xsize_t(off_t len)
 {

git.c

@@ -20,7 +20,7 @@ const char git_more_info_string[] =
 
 static struct startup_info git_startup_info;
 static int use_pager = -1;
-static char orig_cwd[PATH_MAX];
+static char *orig_cwd;
 static const char *env_names[] = {
 	GIT_DIR_ENVIRONMENT,
 	GIT_WORK_TREE_ENVIRONMENT,
@@ -36,8 +36,7 @@ static void save_env(void)
 	if (saved_environment)
 		return;
 	saved_environment = 1;
-	if (!getcwd(orig_cwd, sizeof(orig_cwd)))
-		die_errno("cannot getcwd");
+	orig_cwd = xgetcwd();
 	for (i = 0; i < ARRAY_SIZE(env_names); i++) {
 		orig_env[i] = getenv(env_names[i]);
 		if (orig_env[i])
@@ -48,8 +47,9 @@ static void save_env(void)
 static void restore_env(void)
 {
 	int i;
-	if (*orig_cwd && chdir(orig_cwd))
+	if (orig_cwd && chdir(orig_cwd))
 		die_errno("could not move to %s", orig_cwd);
+	free(orig_cwd);
 	for (i = 0; i < ARRAY_SIZE(env_names); i++) {
 		if (orig_env[i])
 			setenv(env_names[i], orig_env[i], 1);
@@ -161,9 +161,10 @@ static int handle_options(const char ***argv, int *argc, int *envchanged)
 			if (envchanged)
 				*envchanged = 1;
 		} else if (!strcmp(cmd, "--bare")) {
-			static char git_dir[PATH_MAX+1];
+			char *cwd = xgetcwd();
 			is_bare_repository_cfg = 1;
-			setenv(GIT_DIR_ENVIRONMENT, getcwd(git_dir, sizeof(git_dir)), 0);
+			setenv(GIT_DIR_ENVIRONMENT, cwd, 0);
+			free(cwd);
 			setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
 			if (envchanged)
 				*envchanged = 1;