From 9c26de0fd175c2fbb9c67908a0f8bcd37e81252b Mon Sep 17 00:00:00 2001 From: Edward Thomson Date: Mon, 27 Apr 2015 15:38:44 -0400 Subject: [PATCH] config: lock the file for write before reading When writing a configuration file, we want to take a lock on the new file (eg, `config.lock`) before opening the configuration file (`config`) for reading so that we can prevent somebody from changing the contents underneath us. --- src/config_file.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/src/config_file.c b/src/config_file.c index c6c9ef5e2..713183a96 100644 --- a/src/config_file.c +++ b/src/config_file.c @@ -1789,7 +1789,12 @@ static int config_write(diskfile_backend *cfg, const char *key, const regex_t *p struct reader *reader = git_array_get(cfg->readers, 0); struct write_data write_data; - /* TODO: take the lock before reading */ + /* Lock the file */ + if ((result = git_filebuf_open( + &file, cfg->file_path, 0, GIT_CONFIG_FILE_MODE)) < 0) { + git_buf_free(&reader->buffer); + return result; + } /* We need to read in our own config file */ result = git_futils_readbuffer(&reader->buffer, cfg->file_path); @@ -1805,16 +1810,10 @@ static int config_write(diskfile_backend *cfg, const char *key, const regex_t *p reader->eof = 0; data_start = reader->read_ptr; } else { + git_filebuf_cleanup(&file); return -1; /* OS error when reading the file */ } - /* Lock the file */ - if ((result = git_filebuf_open( - &file, cfg->file_path, 0, GIT_CONFIG_FILE_MODE)) < 0) { - git_buf_free(&reader->buffer); - return result; - } - ldot = strrchr(key, '.'); name = ldot + 1; section = git__strndup(key, ldot - key);