Re: [PATCH v2 06/10] setup_git_env: use git_pathdup instead of xmalloc + sprintf

-- >8 --
Subject: [PATCH] setup_git_env: copy getenv return value

The return value of getenv is not guaranteed to survive
across further invocations of setenv or even getenv. When we
are assigning it to globals that last the lifetime of the
program, we should make our own copy.

Signed-off-by: Jeff King <redacted>
---
 environment.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/environment.c b/environment.c
index 4dac5e9..efb2fa0 100644
--- a/environment.c
+++ b/environment.c

@@ -124,6 +124,12 @@ static char *expand_namespace(const char *raw_namespace)
        return strbuf_detach(&buf, NULL);
 }

+static char *git_path_from_env(const char *envvar, const char *path)
+{
+       const char *value = getenv(envvar);
+       return value ? xstrdup(value) : git_pathdup(path);
+}
+
 static void setup_git_env(void)
 {
        const char *gitfile;

@@ -134,19 +140,9 @@ static void setup_git_env(void)
                git_dir = DEFAULT_GIT_DIR_ENVIRONMENT;
        gitfile = read_gitfile(git_dir);
        git_dir = xstrdup(gitfile ? gitfile : git_dir);
-       git_object_dir = getenv(DB_ENVIRONMENT);
-       if (!git_object_dir) {
-               git_object_dir = xmalloc(strlen(git_dir) + 9);
-               sprintf(git_object_dir, "%s/objects", git_dir);
-       }
-       git_index_file = getenv(INDEX_ENVIRONMENT);
-       if (!git_index_file) {
-               git_index_file = xmalloc(strlen(git_dir) + 7);
-               sprintf(git_index_file, "%s/index", git_dir);
-       }
-       git_graft_file = getenv(GRAFT_ENVIRONMENT);
-       if (!git_graft_file)
-               git_graft_file = git_pathdup("info/grafts");
+       git_object_dir = git_path_from_env(DB_ENVIRONMENT, "objects");
+       git_index_file = git_path_from_env(INDEX_ENVIRONMENT, "index");
+       git_graft_file = git_path_from_env(GRAFT_ENVIRONMENT, "info/grafts");
        if (getenv(NO_REPLACE_OBJECTS_ENVIRONMENT))
                check_replace_refs = 0;
        namespace = expand_namespace(getenv(GIT_NAMESPACE_ENVIRONMENT));
--

2.0.0.566.gfe3e6b2