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[PATCH] config: free resources of `struct config_store_data`

From
MÅMartin Ågren <martin.agren@gmail.com>
Date
May 13, 2018, 08:23 UTC
Message-ID
<20180513082303.19582-1-martin.agren@gmail.com>

Commit fee8572c6d (config: avoid using the global variable `store`, 2018-04-09) dropped the staticness of a certain struct, instead letting the users create an instance on the stack and pass around a pointer.

We do not free the memory that the struct tracks. When the struct was static, the memory would always be reachable. Now that we keep the struct on the stack, though, as soon as we return, it goes out of scope and we leak the memory it points to.

Introduce and use a small helper function `config_store_data_clear()` to plug these leaks. This should be safe. The memory tracked here is config parser events. Once the users (`git_config_set_multivar_in_file_gently()` and `git_config_copy_or_rename_section_in_file()` at the moment) are done, no-one should be holding on to a pointer into this memory.

Signed-off-by: Martin Ågren <martin.agren@gmail.com>
---
 config.c | 9 +++++++++
 1 file changed, 9 insertions(+)
diff --git a/config.c b/config.c
index 6f8f1d8c11..83d7d0851a 100644
--- a/config.c
+++ b/config.c
@@ -2333,6 +2333,13 @@ struct config_store_data {
 	unsigned int key_seen:1, section_seen:1, is_keys_section:1;
 };
 
+void config_store_data_clear(struct config_store_data *store)
+{
+	free(store->parsed);
+	free(store->seen);
+	memset(store, 0, sizeof(*store));
+}
+
 static int matches(const char *key, const char *value,
 		   const struct config_store_data *store)
 {
@@ -2887,6 +2894,7 @@ int git_config_set_multivar_in_file_gently(const char *config_filename,
 		munmap(contents, contents_sz);
 	if (in_fd >= 0)
 		close(in_fd);
+	config_store_data_clear(&store);
 	return ret;
 
 write_err_out:
@@ -3127,6 +3135,7 @@ static int git_config_copy_or_rename_section_in_file(const char *config_filename
 	rollback_lock_file(&lock);
 out_no_rollback:
 	free(filename_buf);
+	config_store_data_clear(&store);
 	return ret;
 }
 
-- 
2.17.0.583.g9a75a153ac
Next: Eric Sunshine
Message 1 of 18 in “config: free resources of `struct config_store_data`”
  1. config: free resources of `struct config_store_data`Martin Ågren, May 13, 2018
  2. Eric SunshineMay 13, 2018
  3. Martin ÅgrenMay 13, 2018
  4. 2/1 config: let `config_store_data_clear()` handle `value_regex`Martin Ågren, May 13, 2018
  5. Eric SunshineMay 14, 2018
  6. regex: do not call `regfree()` if compilation failsMartin Ågren, May 20, 2018
  7. Stefan BellerMay 21, 2018
  8. Eric SunshineMay 22, 2018
  9. Martin ÅgrenMay 22, 2018
  10. 3/1 config: let `config_store_data_clear()` handle `key`Martin Ågren, May 13, 2018
  11. Eric SunshineMay 14, 2018
  12. 0/3 config: free resources of `struct config_store_data`Martin Ågren, May 20, 2018
  13. 1/3 config: free resources of `struct config_store_data`Martin Ågren, May 20, 2018
  14. 2/3 config: let `config_store_data_clear()` handle `value_regex`Martin Ågren, May 20, 2018
  15. 3/3 config: let `config_store_data_clear()` handle `key`Martin Ågren, May 20, 2018
  16. Eric SunshineMay 23, 2018
  17. Eric SunshineMay 23, 2018
  18. Martin ÅgrenMay 13, 2018

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