thodg/libgit2/tests/index/racy.c

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• Hash : 5f32c506
  Author :
  Date : 2015-11-16T18:06:52
  

  racy: make git_index_read_index handle raciness Ensure that `git_index_read_index` clears the uptodate bit on files that it modifies. Further, do not propagate the cache from an on-disk index into another on-disk index. Although this should not be done, as `git_index_read_index` is used to bring an in-memory index into another index (that may or may not be on-disk), ensure that we do not accidentally bring in these bits when misused.

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• tests/index/racy.c

• #include "clar_libgit2.h"
  #include "../checkout/checkout_helpers.h"
  
  #include "buffer.h"
  #include "index.h"
  #include "repository.h"
  
  static git_repository *g_repo;
  
  void test_index_racy__initialize(void)
  {
  	cl_git_pass(git_repository_init(&g_repo, "diff_racy", false));
  }
  
  void test_index_racy__cleanup(void)
  {
  	git_repository_free(g_repo);
  	g_repo = NULL;
  
  	cl_fixture_cleanup("diff_racy");
  }
  
  void test_index_racy__diff(void)
  {
  	git_index *index;
  	git_diff *diff;
  	git_buf path = GIT_BUF_INIT;
  
  	cl_git_pass(git_buf_joinpath(&path, git_repository_workdir(g_repo), "A"));
  	cl_git_mkfile(path.ptr, "A");
  
  	/* Put 'A' into the index */
  	cl_git_pass(git_repository_index(&index, g_repo));
  	cl_git_pass(git_index_add_bypath(index, "A"));
  	cl_git_pass(git_index_write(index));
  
  	cl_git_pass(git_diff_index_to_workdir(&diff, g_repo, index, NULL));
  	cl_assert_equal_i(0, git_diff_num_deltas(diff));
  	git_diff_free(diff);
  
  	/* Change its contents quickly, so we get the same timestamp */
  	cl_git_mkfile(path.ptr, "B");
  
  	cl_git_pass(git_diff_index_to_workdir(&diff, g_repo, index, NULL));
  	cl_assert_equal_i(1, git_diff_num_deltas(diff));
  
  	git_index_free(index);
  	git_diff_free(diff);
  	git_buf_free(&path);
  }
  
  void test_index_racy__write_index_just_after_file(void)
  {
  	git_index *index;
  	git_diff *diff;
  	git_buf path = GIT_BUF_INIT;
  	struct timeval times[2];
  
  	/* Make sure we do have a timestamp */
  	cl_git_pass(git_repository_index(&index, g_repo));
  	cl_git_pass(git_index_write(index));
  
  	cl_git_pass(git_buf_joinpath(&path, git_repository_workdir(g_repo), "A"));
  	cl_git_mkfile(path.ptr, "A");
  	/* Force the file's timestamp to be a second after we wrote the index */
  	times[0].tv_sec = index->stamp.mtime.tv_sec + 1;
  	times[0].tv_usec = index->stamp.mtime.tv_nsec / 1000;
  	times[1].tv_sec = index->stamp.mtime.tv_sec + 1;
  	times[1].tv_usec = index->stamp.mtime.tv_nsec / 1000;
  	cl_git_pass(p_utimes(path.ptr, times));
  
  	/*
  	 * Put 'A' into the index, the size field will be filled,
  	 * because the index' on-disk timestamp does not match the
  	 * file's timestamp.
  	 */
  	cl_git_pass(git_index_add_bypath(index, "A"));
  	cl_git_pass(git_index_write(index));
  
  	cl_git_mkfile(path.ptr, "B");
  	/*
  	 * Pretend this index' modification happend a second after the
  	 * file update, and rewrite the file in that same second.
  	 */
  	times[0].tv_sec = index->stamp.mtime.tv_sec + 2;
  	times[0].tv_usec = index->stamp.mtime.tv_nsec / 1000;
  	times[1].tv_sec = index->stamp.mtime.tv_sec + 2;
  	times[0].tv_usec = index->stamp.mtime.tv_nsec / 1000;
  
  	cl_git_pass(p_utimes(git_index_path(index), times));
  	cl_git_pass(p_utimes(path.ptr, times));
  
  	cl_git_pass(git_index_read(index, true));
  
  	cl_git_pass(git_diff_index_to_workdir(&diff, g_repo, index, NULL));
  	cl_assert_equal_i(1, git_diff_num_deltas(diff));
  
  	git_buf_free(&path);
  	git_diff_free(diff);
  	git_index_free(index);
  }
  
  
  static void setup_race(void)
  {
  	git_buf path = GIT_BUF_INIT;
  	git_index *index;
  	const git_index_entry *entry;
  	int i, found_race = 0;
  
  	/* Make sure we do have a timestamp */
  	cl_git_pass(git_repository_index__weakptr(&index, g_repo));
  	cl_git_pass(git_index_write(index));
  
  	cl_git_pass(git_buf_joinpath(&path, git_repository_workdir(g_repo), "A"));
  
  	/* Make sure writing the file, adding and rewriting happen in the same second */
  	for (i = 0; i < 10; i++) {
  		struct stat st;
  		cl_git_mkfile(path.ptr, "A");
  
  		cl_git_pass(git_index_add_bypath(index, "A"));
  		cl_git_mkfile(path.ptr, "B");
  		cl_git_pass(git_index_write(index));
  
  		cl_git_mkfile(path.ptr, "");
  
  		cl_git_pass(p_stat(path.ptr, &st));
  		cl_assert(entry = git_index_get_bypath(index, "A", 0));
  		if (entry->mtime.seconds == (int32_t) st.st_mtime) {
  			found_race = 1;
  			break;
  		}
  	}
  
  	if (!found_race)
  		cl_fail("failed to find race after 10 attempts");
  
  	git_buf_free(&path);
  }
  
  void test_index_racy__smudges_index_entry_on_save(void)
  {
  	git_index *index;
  	const git_index_entry *entry;
  
  	setup_race();
  
  	/* write the index, which will smudge anything that had the same timestamp
  	 * as the index when the index was loaded.  that way future loads of the
  	 * index (with the new timestamp) will know that these files were not
  	 * clean.
  	 */
  
  	cl_git_pass(git_repository_index__weakptr(&index, g_repo));
  	cl_git_pass(git_index_write(index));
  
  	cl_assert(entry = git_index_get_bypath(index, "A", 0));
  	cl_assert_equal_i(0, entry->file_size);
  }
  
  void test_index_racy__detects_diff_of_change_in_identical_timestamp(void)
  {
  	git_index *index;
  	git_diff *diff;
  
  	cl_git_pass(git_repository_index__weakptr(&index, g_repo));
  
  	setup_race();
  
  	cl_git_pass(git_diff_index_to_workdir(&diff, g_repo, index, NULL));
  	cl_assert_equal_i(1, git_diff_num_deltas(diff));
  
  	git_diff_free(diff);
  }
  
  static void setup_uptodate_files(void)
  {
  	git_buf path = GIT_BUF_INIT;
  	git_index *index;
  	git_index_entry new_entry = {0};
  
  	cl_git_pass(git_repository_index(&index, g_repo));
  
  	cl_git_pass(git_buf_joinpath(&path, git_repository_workdir(g_repo), "A"));
  	cl_git_mkfile(path.ptr, "A");
  
  	/* Put 'A' into the index */
  	cl_git_pass(git_index_add_bypath(index, "A"));
  
  	/* Put 'B' into the index */
  	new_entry.path = "B";
  	new_entry.mode = GIT_FILEMODE_BLOB;
  	cl_git_pass(git_index_add(index, &new_entry));
  
  	/* Put 'C' into the index */
  	new_entry.path = "C";
  	new_entry.mode = GIT_FILEMODE_BLOB;
  	cl_git_pass(git_index_add_frombuffer(index, &new_entry, "hello!\n", 7));
  
  	git_index_free(index);
  	git_buf_free(&path);
  }
  
  void test_index_racy__adding_to_index_is_uptodate(void)
  {
  	git_index *index;
  	const git_index_entry *entry;
  
  	setup_uptodate_files();
  
  	cl_git_pass(git_repository_index(&index, g_repo));
  
  	/* ensure that they're all uptodate */
  	cl_assert((entry = git_index_get_bypath(index, "A", 0)));
  	cl_assert_equal_i(GIT_IDXENTRY_UPTODATE, (entry->flags_extended & GIT_IDXENTRY_UPTODATE));
  
  	cl_assert((entry = git_index_get_bypath(index, "B", 0)));
  	cl_assert_equal_i(GIT_IDXENTRY_UPTODATE, (entry->flags_extended & GIT_IDXENTRY_UPTODATE));
  
  	cl_assert((entry = git_index_get_bypath(index, "C", 0)));
  	cl_assert_equal_i(GIT_IDXENTRY_UPTODATE, (entry->flags_extended & GIT_IDXENTRY_UPTODATE));
  
  	cl_git_pass(git_index_write(index));
  
  	git_index_free(index);
  }
  
  void test_index_racy__reading_clears_uptodate_bit(void)
  {
  	git_index *index;
  	const git_index_entry *entry;
  
  	setup_uptodate_files();
  
  	cl_git_pass(git_repository_index(&index, g_repo));
  	cl_git_pass(git_index_write(index));
  
  	cl_git_pass(git_index_read(index, true));
  
  	/* ensure that no files are uptodate */
  	cl_assert((entry = git_index_get_bypath(index, "A", 0)));
  	cl_assert_equal_i(0, (entry->flags_extended & GIT_IDXENTRY_UPTODATE));
  
  	cl_assert((entry = git_index_get_bypath(index, "B", 0)));
  	cl_assert_equal_i(0, (entry->flags_extended & GIT_IDXENTRY_UPTODATE));
  
  	cl_assert((entry = git_index_get_bypath(index, "C", 0)));
  	cl_assert_equal_i(0, (entry->flags_extended & GIT_IDXENTRY_UPTODATE));
  
  	git_index_free(index);
  }
  
  void test_index_racy__read_tree_clears_uptodate_bit(void)
  {
  	git_index *index;
  	git_tree *tree;
  	const git_index_entry *entry;
  	git_oid id;
  
  	setup_uptodate_files();
  
  	cl_git_pass(git_repository_index(&index, g_repo));
  	cl_git_pass(git_index_write_tree_to(&id, index, g_repo));
  	cl_git_pass(git_tree_lookup(&tree, g_repo, &id));
  	cl_git_pass(git_index_read_tree(index, tree));
  
  	/* ensure that no files are uptodate */
  	cl_assert((entry = git_index_get_bypath(index, "A", 0)));
  	cl_assert_equal_i(0, (entry->flags_extended & GIT_IDXENTRY_UPTODATE));
  
  	cl_assert((entry = git_index_get_bypath(index, "B", 0)));
  	cl_assert_equal_i(0, (entry->flags_extended & GIT_IDXENTRY_UPTODATE));
  
  	cl_assert((entry = git_index_get_bypath(index, "C", 0)));
  	cl_assert_equal_i(0, (entry->flags_extended & GIT_IDXENTRY_UPTODATE));
  
  	git_tree_free(tree);
  	git_index_free(index);
  }
  
  void test_index_racy__read_index_smudges(void)
  {
  	git_index *index, *newindex;
  	const git_index_entry *entry;
  
  	/* if we are reading an index into our new index, ensure that any
  	 * racy entries in the index that we're reading are smudged so that
  	 * we don't propagate their timestamps without further investigation.
  	 */
  	setup_race();
  
  	cl_git_pass(git_repository_index(&index, g_repo));
  	cl_git_pass(git_index_new(&newindex));
  	cl_git_pass(git_index_read_index(newindex, index));
  
  	cl_assert(entry = git_index_get_bypath(newindex, "A", 0));
  	cl_assert_equal_i(0, entry->file_size);
  
  	git_index_free(index);
  	git_index_free(newindex);
  }
  
  void test_index_racy__read_index_clears_uptodate_bit(void)
  {
  	git_index *index, *newindex;
  	const git_index_entry *entry;
  	git_oid id;
  
  	setup_uptodate_files();
  
  	cl_git_pass(git_repository_index(&index, g_repo));
  	cl_git_pass(git_index_new(&newindex));
  	cl_git_pass(git_index_read_index(newindex, index));
  
  	/* ensure that files brought in from the other index are not uptodate */
  	cl_assert((entry = git_index_get_bypath(newindex, "A", 0)));
  	cl_assert_equal_i(0, (entry->flags_extended & GIT_IDXENTRY_UPTODATE));
  
  	cl_assert((entry = git_index_get_bypath(newindex, "B", 0)));
  	cl_assert_equal_i(0, (entry->flags_extended & GIT_IDXENTRY_UPTODATE));
  
  	cl_assert((entry = git_index_get_bypath(newindex, "C", 0)));
  	cl_assert_equal_i(0, (entry->flags_extended & GIT_IDXENTRY_UPTODATE));
  
  	git_index_free(index);
  	git_index_free(newindex);
  }
  

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