Use git_buf for path storage instead of stack-based buffers

This converts virtually all of the places that allocate GIT_PATH_MAX
buffers on the stack for manipulating paths to use git_buf objects
instead.  The patch is pretty careful not to touch the public API
for libgit2, so there are a few places that still use GIT_PATH_MAX.

This extends and changes some details of the git_buf implementation
to add a couple of extra functions and to make error handling easier.

This includes serious alterations to all the path.c functions, and
several of the fileops.c ones, too.  Also, there are a number of new
functions that parallel existing ones except that use a git_buf
instead of a stack-based buffer (such as git_config_find_global_r
that exists alongsize git_config_find_global).

This also modifies the win32 version of p_realpath to allocate whatever
buffer size is needed to accommodate the realpath instead of hardcoding
a GIT_PATH_MAX limit, but that change needs to be tested still.

1 files changed, 14 insertions, 8 deletions

diff --git a/src/fetch.c b/src/fetch.c
index f447248c5..f9e15b232 100644
--- a/src/fetch.c
+++ b/src/fetch.c
@@ -115,25 +115,31 @@ int git_fetch_download_pack(char **out, git_remote *remote)
 }
 
 /* Receiving data from a socket and storing it is pretty much the same for git and HTTP */
-int git_fetch__download_pack(char **out, const char *buffered, size_t buffered_size,
-                             GIT_SOCKET fd, git_repository *repo)
+int git_fetch__download_pack(
+	char **out,
+	const char *buffered,
+	size_t buffered_size,
+	GIT_SOCKET fd,
+	git_repository *repo)
 {
 	git_filebuf file = GIT_FILEBUF_INIT;
 	int error;
-	char buff[1024], path[GIT_PATH_MAX];
+	char buff[1024];
+	git_buf path = GIT_BUF_INIT;
 	static const char suff[] = "/objects/pack/pack-received";
 	gitno_buffer buf;
 
-
-	git_path_join(path, repo->path_repository, suff);
-
 	gitno_buffer_setup(&buf, buff, sizeof(buff), fd);
 
 	if (memcmp(buffered, "PACK", strlen("PACK"))) {
 		return git__throw(GIT_ERROR, "The pack doesn't start with the signature");
 	}
 
-	error = git_filebuf_open(&file, path, GIT_FILEBUF_TEMPORARY);
+	error = git_buf_joinpath(&path, repo->path_repository, suff);
+	if (error < GIT_SUCCESS)
+		goto cleanup;
+
+	error = git_filebuf_open(&file, path.ptr, GIT_FILEBUF_TEMPORARY);
 	if (error < GIT_SUCCESS)
 		goto cleanup;
 
@@ -166,7 +172,7 @@ int git_fetch__download_pack(char **out, const char *buffered, size_t buffered_s
 cleanup:
 	if (error < GIT_SUCCESS)
 		git_filebuf_cleanup(&file);
+    git_buf_free(&path);
 
 	return error;
-
 }