From 15431ca651050ba315fa4e2e74527f6d115e706c Mon Sep 17 00:00:00 2001 From: Kirill Smelkov Date: Thu, 11 Nov 2010 21:08:23 +0300 Subject: [PATCH] setup: make sure git_dir path is in a permanent buffer, getenv(3) case getenv(3) returns not-permanent buffer which may be changed by e.g. putenv(3) call (*). In practice I've noticed this when trying to do `git commit -m abc` inside msysgit under wine, getting $ git commit -m abc fatal: could not open 'DIR=.git/COMMIT_EDITMSG': No such file or directory ^^^^ (notice introduced 'DIR=' artifact.) The problem was showing itself only with -m option, and actually, as debugging showed, originally git_dir = getenv("GIT_DIR") returned pointer to "GIT_DIR=.git\0" ^ git_dir , we stored it in git_dir, than, after processing -m git-commit option, we did setenv("GIT_EDITOR", ":") which as (*) says changed environment variables memory layout - something like this "...\0GIT_DIR=.git\0" ^ git_dir and oops - we got wrong git_dir. Avoid that by strdupping getenv("GIT_DIR") result like we did in 06f354 (setup: make sure git dir path is in a permanent buffer). Unfortunately this also shows that other getenv usage inside git needs auditing... (*) from man 3 getenv: The implementation of getenv() is not required to be reentrant. The string pointed to by the return value of getenv() may be statically allocated, and can be modified by a subsequent call to getenv(), putenv(3), setenv(3), or unsetenv(3). Cc: Jonathan Nieder Signed-off-by: Kirill Smelkov Signed-off-by: Junio C Hamano --- environment.c | 1 + 1 file changed, 1 insertion(+) diff --git a/environment.c b/environment.c index de5581fe5..18aded6dc 100644 --- a/environment.c +++ b/environment.c @@ -87,6 +87,7 @@ const char * const local_repo_env[LOCAL_REPO_ENV_SIZE + 1] = { static void setup_git_env(void) { git_dir = getenv(GIT_DIR_ENVIRONMENT); + git_dir = git_dir ? xstrdup(git_dir) : NULL; if (!git_dir) { git_dir = read_gitfile_gently(DEFAULT_GIT_DIR_ENVIRONMENT); git_dir = git_dir ? xstrdup(git_dir) : NULL; -- 2.30.2