Merge branch 'ar/maint-mksnpath' into maint

* ar/maint-mksnpath:
  Use git_pathdup instead of xstrdup(git_path(...))
  git_pathdup: returns xstrdup-ed copy of the formatted path
  Fix potentially dangerous use of git_path in ref.c
  Add git_snpath: a .git path formatting routine with output buffer
  Fix potentially dangerous uses of mkpath and git_path
  Fix mkpath abuse in dwim_ref and dwim_log of sha1_name.c
  Add mksnpath which allows you to specify the output buffer

Conflicts:
	builtin-revert.c
	rerere.c

13 files changed, 84 insertions, 19 deletions

diff --git a/builtin-apply.c b/builtin-apply.c
index e9d49f133..50b623e54 100644
--- a/builtin-apply.c
+++ b/builtin-apply.c
@@ -2850,8 +2850,8 @@ static void create_one_file(char *path, unsigned mode, const char *buf, unsigned
 		unsigned int nr = getpid();
 
 		for (;;) {
-			const char *newpath;
-			newpath = mkpath("%s~%u", path, nr);
+			char newpath[PATH_MAX];
+			mksnpath(newpath, sizeof(newpath), "%s~%u", path, nr);
 			if (!try_create_file(newpath, mode, buf, size)) {
 				if (!rename(newpath, path))
 					return;
diff --git a/builtin-config.c b/builtin-config.c
index 91fdc4985..f71016204 100644
--- a/builtin-config.c
+++ b/builtin-config.c
@@ -84,7 +84,7 @@ static int get_value(const char* key_, const char* regex_)
 	local = config_exclusive_filename;
 	if (!local) {
 		const char *home = getenv("HOME");
-		local = repo_config = xstrdup(git_path("config"));
+		local = repo_config = git_pathdup("config");
 		if (git_config_global() && home)
 			global = xstrdup(mkpath("%s/.gitconfig", home));
 		if (git_config_system())
diff --git a/builtin-reflog.c b/builtin-reflog.c
index 196fa03b7..da96da317 100644
--- a/builtin-reflog.c
+++ b/builtin-reflog.c
@@ -277,11 +277,11 @@ static int expire_reflog(const char *ref, const unsigned char *sha1, int unused,
 	lock = lock_any_ref_for_update(ref, sha1, 0);
 	if (!lock)
 		return error("cannot lock ref '%s'", ref);
-	log_file = xstrdup(git_path("logs/%s", ref));
+	log_file = git_pathdup("logs/%s", ref);
 	if (!file_exists(log_file))
 		goto finish;
 	if (!cmd->dry_run) {
-		newlog_path = xstrdup(git_path("logs/%s.lock", ref));
+		newlog_path = git_pathdup("logs/%s.lock", ref);
 		cb.newlog = fopen(newlog_path, "w");
 	}
 
diff --git a/builtin-revert.c b/builtin-revert.c
index 786a956f2..74845ef8e 100644
--- a/builtin-revert.c
+++ b/builtin-revert.c
@@ -269,7 +269,7 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 	int i;
 	char *oneline, *reencoded_message = NULL;
 	const char *message, *encoding;
-	char *defmsg = xstrdup(git_path("MERGE_MSG"));
+	char *defmsg = git_pathdup("MERGE_MSG");
 
 	git_config(git_default_config, NULL);
 	me = action == REVERT ? "revert" : "cherry-pick";
diff --git a/builtin-tag.c b/builtin-tag.c
index 5b141c584..843e9ac05 100644
--- a/builtin-tag.c
+++ b/builtin-tag.c
@@ -283,7 +283,7 @@ static void create_tag(const unsigned char *object, const char *tag,
 		int fd;
 
 		/* write the template message before editing: */
-		path = xstrdup(git_path("TAG_EDITMSG"));
+		path = git_pathdup("TAG_EDITMSG");
 		fd = open(path, O_CREAT | O_TRUNC | O_WRONLY, 0600);
 		if (fd < 0)
 			die("could not create file '%s': %s",
diff --git a/cache.h b/cache.h
index 39f24ad82..a1e4982cd 100644
--- a/cache.h
+++ b/cache.h
@@ -484,6 +484,13 @@ extern int check_repository_format(void);
 #define DATA_CHANGED    0x0020
 #define TYPE_CHANGED    0x0040
 
+extern char *mksnpath(char *buf, size_t n, const char *fmt, ...)
+	__attribute__((format (printf, 3, 4)));
+extern char *git_snpath(char *buf, size_t n, const char *fmt, ...)
+	__attribute__((format (printf, 3, 4)));
+extern char *git_pathdup(const char *fmt, ...)
+	__attribute__((format (printf, 1, 2)));
+
 /* Return a statically allocated filename matching the sha1 signature */
 extern char *mkpath(const char *fmt, ...) __attribute__((format (printf, 1, 2)));
 extern char *git_path(const char *fmt, ...) __attribute__((format (printf, 1, 2)));
diff --git a/config.c b/config.c
index 53f04a076..82807c83b 100644
--- a/config.c
+++ b/config.c
@@ -630,7 +630,7 @@ int git_config(config_fn_t fn, void *data)
 		free(user_config);
 	}
 
-	repo_config = xstrdup(git_path("config"));
+	repo_config = git_pathdup("config");
 	ret += git_config_from_file(fn, repo_config, data);
 	free(repo_config);
 	return ret;
@@ -872,7 +872,7 @@ int git_config_set_multivar(const char* key, const char* value,
 	if (config_exclusive_filename)
 		config_filename = xstrdup(config_exclusive_filename);
 	else
-		config_filename = xstrdup(git_path("config"));
+		config_filename = git_pathdup("config");
 
 	/*
 	 * Since "key" actually contains the section name and the real
@@ -1132,7 +1132,7 @@ int git_config_rename_section(const char *old_name, const char *new_name)
 	if (config_exclusive_filename)
 		config_filename = xstrdup(config_exclusive_filename);
 	else
-		config_filename = xstrdup(git_path("config"));
+		config_filename = git_pathdup("config");
 	out_fd = hold_lock_file_for_update(lock, config_filename, 0);
 	if (out_fd < 0) {
 		ret = error("could not lock config file %s", config_filename);
diff --git a/environment.c b/environment.c
index 0c6d11f6a..df4f03a95 100644
--- a/environment.c
+++ b/environment.c
@@ -71,7 +71,7 @@ static void setup_git_env(void)
 	}
 	git_graft_file = getenv(GRAFT_ENVIRONMENT);
 	if (!git_graft_file)
-		git_graft_file = xstrdup(git_path("info/grafts"));
+		git_graft_file = git_pathdup("info/grafts");
 }
 
 int is_bare_repository(void)
diff --git a/path.c b/path.c
index c1cb54b7b..eb2401753 100644
--- a/path.c
+++ b/path.c
@@ -32,6 +32,60 @@ static char *cleanup_path(char *path)
 	return path;
 }
 
+char *mksnpath(char *buf, size_t n, const char *fmt, ...)
+{
+	va_list args;
+	unsigned len;
+
+	va_start(args, fmt);
+	len = vsnprintf(buf, n, fmt, args);
+	va_end(args);
+	if (len >= n) {
+		snprintf(buf, n, bad_path);
+		return buf;
+	}
+	return cleanup_path(buf);
+}
+
+static char *git_vsnpath(char *buf, size_t n, const char *fmt, va_list args)
+{
+	const char *git_dir = get_git_dir();
+	size_t len;
+
+	len = strlen(git_dir);
+	if (n < len + 1)
+		goto bad;
+	memcpy(buf, git_dir, len);
+	if (len && !is_dir_sep(git_dir[len-1]))
+		buf[len++] = '/';
+	len += vsnprintf(buf + len, n - len, fmt, args);
+	if (len >= n)
+		goto bad;
+	return cleanup_path(buf);
+bad:
+	snprintf(buf, n, bad_path);
+	return buf;
+}
+
+char *git_snpath(char *buf, size_t n, const char *fmt, ...)
+{
+	va_list args;
+	va_start(args, fmt);
+	(void)git_vsnpath(buf, n, fmt, args);
+	va_end(args);
+	return buf;
+}
+
+char *git_pathdup(const char *fmt, ...)
+{
+	char path[PATH_MAX];
+	va_list args;
+	va_start(args, fmt);
+	(void)git_vsnpath(path, sizeof(path), fmt, args);
+	va_end(args);
+	return xstrdup(path);
+}
+
 char *mkpath(const char *fmt, ...)
 {
 	va_list args;
diff --git a/refs.c b/refs.c
index 156714e54..48271a99a 100644
--- a/refs.c
+++ b/refs.c
@@ -401,7 +401,7 @@ const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *
 		*flag = 0;
 
 	for (;;) {
-		const char *path = git_path("%s", ref);
+		char path[PATH_MAX];
 		struct stat st;
 		char *buf;
 		int fd;
@@ -409,6 +409,7 @@ const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *
 		if (--depth < 0)
 			return NULL;
 
+		git_snpath(path, sizeof(path), "%s", ref);
 		/* Special case: non-existing file.
 		 * Not having the refs/heads/new-branch is OK
 		 * if we are writing into it, so is .git/HEAD
@@ -1136,13 +1137,14 @@ static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
 	int logfd, written, oflags = O_APPEND | O_WRONLY;
 	unsigned maxlen, len;
 	int msglen;
-	char *log_file, *logrec;
+	char log_file[PATH_MAX];
+	char *logrec;
 	const char *committer;
 
 	if (log_all_ref_updates < 0)
 		log_all_ref_updates = !is_bare_repository();
 
-	log_file = git_path("logs/%s", ref_name);
+	git_snpath(log_file, sizeof(log_file), "logs/%s", ref_name);
 
 	if (log_all_ref_updates &&
 	    (!prefixcmp(ref_name, "refs/heads/") ||
@@ -1271,7 +1273,7 @@ int create_symref(const char *ref_target, const char *refs_heads_master,
 	const char *lockpath;
 	char ref[1000];
 	int fd, len, written;
-	char *git_HEAD = xstrdup(git_path("%s", ref_target));
+	char *git_HEAD = git_pathdup("%s", ref_target);
 	unsigned char old_sha1[20], new_sha1[20];
 
 	if (logmsg && read_ref(ref_target, old_sha1))
diff --git a/rerere.c b/rerere.c
index 2b7a99d72..a0d477aac 100644
--- a/rerere.c
+++ b/rerere.c
@@ -345,7 +345,7 @@ int setup_rerere(struct string_list *merge_rr)
 	if (!is_rerere_enabled())
 		return -1;
 
-	merge_rr_path = xstrdup(git_path("MERGE_RR"));
+	merge_rr_path = git_pathdup("MERGE_RR");
 	fd = hold_lock_file_for_update(&write_lock, merge_rr_path,
 				       LOCK_DIE_ON_ERROR);
 	read_rr(merge_rr);
diff --git a/server-info.c b/server-info.c
index c1c073b2f..66b0d9d87 100644
--- a/server-info.c
+++ b/server-info.c
@@ -25,7 +25,7 @@ static int add_info_ref(const char *path, const unsigned char *sha1, int flag, v
 
 static int update_info_refs(int force)
 {
-	char *path0 = xstrdup(git_path("info/refs"));
+	char *path0 = git_pathdup("info/refs");
 	int len = strlen(path0);
 	char *path1 = xmalloc(len + 2);
 
diff --git a/sha1_name.c b/sha1_name.c
index 4fb77f886..75a5a7e96 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -245,11 +245,13 @@ int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
 
 	*ref = NULL;
 	for (p = ref_rev_parse_rules; *p; p++) {
+		char fullref[PATH_MAX];
 		unsigned char sha1_from_ref[20];
 		unsigned char *this_result;
 
 		this_result = refs_found ? sha1_from_ref : sha1;
-		r = resolve_ref(mkpath(*p, len, str), this_result, 1, NULL);
+		mksnpath(fullref, sizeof(fullref), *p, len, str);
+		r = resolve_ref(fullref, this_result, 1, NULL);
 		if (r) {
 			if (!refs_found++)
 				*ref = xstrdup(r);
@@ -272,7 +274,7 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
 		char path[PATH_MAX];
 		const char *ref, *it;
 
-		strcpy(path, mkpath(*p, len, str));
+		mksnpath(path, sizeof(path), *p, len, str);
 		ref = resolve_ref(path, hash, 1, NULL);
 		if (!ref)
 			continue;