real_path: remove unsafe API
Returning a shared buffer invites very subtle bugs due to reentrancy or
multi-threading, as demonstrated by the previous patch.
There was an unfinished effort to abolish this [1].
Let's finally rid of `real_path()`, using `strbuf_realpath()` instead.
This patch uses a local `strbuf` for most places where `real_path()` was
previously called.
However, two places return the value of `real_path()` to the caller. For
them, a `static` local `strbuf` was added, effectively pushing the
problem one level higher:
read_gitfile_gently()
get_superproject_working_tree()
[1] https://lore.kernel.org/git/1480964316-99305-1-git-send-email-bmwill@google.com/
Signed-off-by: Alexandr Miloslavskiy <alexandr.miloslavskiy@syntevo.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/builtin/worktree.c b/builtin/worktree.c
index 24f2280..d99db35 100644
--- a/builtin/worktree.c
+++ b/builtin/worktree.c
@@ -258,7 +258,7 @@ static int add_worktree(const char *path, const char *refname,
const struct add_opts *opts)
{
struct strbuf sb_git = STRBUF_INIT, sb_repo = STRBUF_INIT;
- struct strbuf sb = STRBUF_INIT;
+ struct strbuf sb = STRBUF_INIT, realpath = STRBUF_INIT;
const char *name;
struct child_process cp = CHILD_PROCESS_INIT;
struct argv_array child_env = ARGV_ARRAY_INIT;
@@ -330,9 +330,11 @@ static int add_worktree(const char *path, const char *refname,
strbuf_reset(&sb);
strbuf_addf(&sb, "%s/gitdir", sb_repo.buf);
- write_file(sb.buf, "%s", real_path(sb_git.buf));
+ strbuf_realpath(&realpath, sb_git.buf, 1);
+ write_file(sb.buf, "%s", realpath.buf);
+ strbuf_realpath(&realpath, get_git_common_dir(), 1);
write_file(sb_git.buf, "gitdir: %s/worktrees/%s",
- real_path(get_git_common_dir()), name);
+ realpath.buf, name);
/*
* This is to keep resolve_ref() happy. We need a valid HEAD
* or is_git_directory() will reject the directory. Any value which
@@ -418,6 +420,7 @@ static int add_worktree(const char *path, const char *refname,
strbuf_release(&sb_repo);
strbuf_release(&sb_git);
strbuf_release(&sb_name);
+ strbuf_release(&realpath);
return ret;
}
