config.c: fix mmap leak when writing config

We mmap the existing config file, but fail to unmap it if we
hit an error. The function already has a shared exit path,
so we can fix this by moving the mmap pointer to the
function scope and clearing it in the shared exit.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/config.c b/config.c
index 752e2e227f56edfb7b2ad168798c110c14a2c5e8..dc7f8b2abc8f994ea7045bdec827a07ef9d2a847 100644 (file)
--- a/config.c
+++ b/config.c
@@ -1934,6 +1934,8 @@ int git_config_set_multivar_in_file(const char *config_filename,
        int ret;
        struct lock_file *lock = NULL;
        char *filename_buf = NULL;
        int ret;
        struct lock_file *lock = NULL;
        char *filename_buf = NULL;

+       char *contents = NULL;
+       size_t contents_sz;

 
        /* parse-key returns negative; flip the sign to feed exit(3) */
        ret = 0 - git_config_parse_key(key, &store.key, &store.baselen);
 
        /* parse-key returns negative; flip the sign to feed exit(3) */
        ret = 0 - git_config_parse_key(key, &store.key, &store.baselen);


@@ -1983,8 +1985,7 @@ int git_config_set_multivar_in_file(const char *config_filename,
                        goto write_err_out;
        } else {
                struct stat st;
                        goto write_err_out;
        } else {
                struct stat st;

-               char *contents;
-               size_t contents_sz, copy_begin, copy_end;
+               size_t copy_begin, copy_end;

                int i, new_line = 0;
 
                if (value_regex == NULL)
                int i, new_line = 0;
 
                if (value_regex == NULL)


@@ -2103,8 +2104,6 @@ int git_config_set_multivar_in_file(const char *config_filename,
                                          contents_sz - copy_begin) <
                            contents_sz - copy_begin)
                                goto write_err_out;
                                          contents_sz - copy_begin) <
                            contents_sz - copy_begin)
                                goto write_err_out;

-
-               munmap(contents, contents_sz);

        }
 
        if (commit_lock_file(lock) < 0) {
        }
 
        if (commit_lock_file(lock) < 0) {


@@ -2130,6 +2129,8 @@ int git_config_set_multivar_in_file(const char *config_filename,
        if (lock)
                rollback_lock_file(lock);
        free(filename_buf);
        if (lock)
                rollback_lock_file(lock);
        free(filename_buf);

+       if (contents)
+               munmap(contents, contents_sz);

        return ret;
 
 write_err_out:
        return ret;
 
 write_err_out: