Merge pull request #5282 from pks-t/pks/config-file-iterator-race

config_file: fix race when creating an iterator
2026-01-25 11:06:32 +00:00 · 2019-11-05 13:04:10 +01:00
parent 82d7a114eb 56b203a5e0
commit 5d773a1833
2 changed files with 99 additions and 100 deletions
--- a/src/config_file.c
+++ b/src/config_file.c
@@ -9,23 +9,17 @@

 #include "git2/config.h"
 #include "git2/sys/config.h"
-#include "git2/types.h"

 #include "array.h"
-#include "buf_text.h"
 #include "buffer.h"
 #include "config_backend.h"
 #include "config_entries.h"
 #include "config_parse.h"
 #include "filebuf.h"
 #include "regexp.h"
-#include "strmap.h"
 #include "sysdir.h"
 #include "wildmatch.h"

-#include <ctype.h>
-#include <sys/types.h>
-
 /* Max depth for [include] directives */
 #define MAX_INCLUDE_DEPTH 10

@@ -60,9 +54,9 @@ typedef struct {
 	unsigned int depth;
 } config_file_parse_data;

-static int config_read(git_config_entries *entries, const git_repository *repo, config_file *file, git_config_level_t level, int depth);
-static int config_read_buffer(git_config_entries *entries, const git_repository *repo, config_file *file, git_config_level_t level, int depth, const char *buf, size_t buflen);
-static int config_write(config_file_backend *cfg, const char *orig_key, const char *key, const git_regexp *preg, const char *value);
+static int config_file_read(git_config_entries *entries, const git_repository *repo, config_file *file, git_config_level_t level, int depth);
+static int config_file_read_buffer(git_config_entries *entries, const git_repository *repo, config_file *file, git_config_level_t level, int depth, const char *buf, size_t buflen);
+static int config_file_write(config_file_backend *cfg, const char *orig_key, const char *key, const git_regexp *preg, const char *value);
 static char *escape_value(const char *ptr);

 /**
@@ -70,21 +64,21 @@ static char *escape_value(const char *ptr);
 * refcount. This is its own function to make sure we use the mutex to
 * avoid the map pointer from changing under us.
 */
-static git_config_entries *diskfile_entries_take(config_file_backend *b)
+static int config_file_entries_take(git_config_entries **out, config_file_backend *b)
 {
-	git_config_entries *entries;
+	int error;

-	if (git_mutex_lock(&b->values_mutex) < 0) {
-	    git_error_set(GIT_ERROR_OS, "failed to lock config backend");
-	    return NULL;
+	if ((error = git_mutex_lock(&b->values_mutex)) < 0) {
+		git_error_set(GIT_ERROR_OS, "failed to lock config backend");
+		return error;
 	}

-	entries = b->entries;
-	git_config_entries_incref(entries);
+	git_config_entries_incref(b->entries);
+	*out = b->entries;

 	git_mutex_unlock(&b->values_mutex);

-	return entries;
+	return 0;
 }

 static void config_file_clear(config_file *file)
@@ -103,7 +97,7 @@ static void config_file_clear(config_file *file)
 	git__free(file->path);
 }

-static int config_open(git_config_backend *cfg, git_config_level_t level, const git_repository *repo)
+static int config_file_open(git_config_backend *cfg, git_config_level_t level, const git_repository *repo)
 {
 	config_file_backend *b = GIT_CONTAINER_OF(cfg, config_file_backend, parent);
 	int res;
@@ -117,7 +111,7 @@ static int config_open(git_config_backend *cfg, git_config_level_t level, const
 	if (!git_path_exists(b->file.path))
 		return 0;

-	if (res < 0 || (res = config_read(b->entries, repo, &b->file, level, 0)) < 0) {
+	if (res < 0 || (res = config_file_read(b->entries, repo, &b->file, level, 0)) < 0) {
 		git_config_entries_free(b->entries);
 		b->entries = NULL;
 	}
@@ -125,7 +119,7 @@ static int config_open(git_config_backend *cfg, git_config_level_t level, const
 	return res;
 }

-static int config_is_modified(int *modified, config_file *file)
+static int config_file_is_modified(int *modified, config_file *file)
 {
 	config_file *include;
 	git_buf buf = GIT_BUF_INIT;
@@ -151,7 +145,7 @@ static int config_is_modified(int *modified, config_file *file)

 check_includes:
 	git_array_foreach(file->includes, i, include) {
-		if ((error = config_is_modified(modified, include)) < 0 || *modified)
+		if ((error = config_file_is_modified(modified, include)) < 0 || *modified)
 			goto out;
 	}

@@ -161,7 +155,7 @@ out:
 	return error;
 }

-static int config_set_entries(git_config_backend *cfg, git_config_entries *entries)
+static int config_file_set_entries(git_config_backend *cfg, git_config_entries *entries)
 {
 	config_file_backend *b = GIT_CONTAINER_OF(cfg, config_file_backend, parent);
 	git_config_entries *old = NULL;
@@ -193,16 +187,16 @@ out:
 	return error;
 }

-static int config_refresh_from_buffer(git_config_backend *cfg, const char *buf, size_t buflen)
+static int config_file_refresh_from_buffer(git_config_backend *cfg, const char *buf, size_t buflen)
 {
 	config_file_backend *b = GIT_CONTAINER_OF(cfg, config_file_backend, parent);
 	git_config_entries *entries = NULL;
 	int error;

 	if ((error = git_config_entries_new(&entries)) < 0 ||
-	    (error = config_read_buffer(entries, b->repo, &b->file,
-					b->level, 0, buf, buflen)) < 0 ||
-	    (error = config_set_entries(cfg, entries)) < 0)
+	    (error = config_file_read_buffer(entries, b->repo, &b->file,
+					     b->level, 0, buf, buflen)) < 0 ||
+	    (error = config_file_set_entries(cfg, entries)) < 0)
 		goto out;

 	entries = NULL;
@@ -211,7 +205,7 @@ out:
 	return error;
 }

-static int config_refresh(git_config_backend *cfg)
+static int config_file_refresh(git_config_backend *cfg)
 {
 	config_file_backend *b = GIT_CONTAINER_OF(cfg, config_file_backend, parent);
 	git_config_entries *entries = NULL;
@@ -220,15 +214,15 @@ static int config_refresh(git_config_backend *cfg)
 	if (cfg->readonly)
 		return 0;

-	if ((error = config_is_modified(&modified, &b->file)) < 0 && error != GIT_ENOTFOUND)
+	if ((error = config_file_is_modified(&modified, &b->file)) < 0 && error != GIT_ENOTFOUND)
 		goto out;

 	if (!modified)
 		return 0;

 	if ((error = git_config_entries_new(&entries)) < 0 ||
-	    (error = config_read(entries, b->repo, &b->file, b->level, 0)) < 0 ||
-	    (error = config_set_entries(cfg, entries)) < 0)
+	    (error = config_file_read(entries, b->repo, &b->file, b->level, 0)) < 0 ||
+	    (error = config_file_set_entries(cfg, entries)) < 0)
 		goto out;

 	entries = NULL;
@@ -238,7 +232,7 @@ out:
 	return (error == GIT_ENOTFOUND) ? 0 : error;
 }

-static void backend_free(git_config_backend *_backend)
+static void config_file_free(git_config_backend *_backend)
 {
 	config_file_backend *backend = GIT_CONTAINER_OF(_backend, config_file_backend, parent);

@@ -251,26 +245,33 @@ static void backend_free(git_config_backend *_backend)
 	git__free(backend);
 }

-static int config_iterator_new(
+static int config_file_iterator(
 	git_config_iterator **iter,
 	struct git_config_backend *backend)
 {
 	config_file_backend *b = GIT_CONTAINER_OF(backend, config_file_backend, parent);
-	git_config_entries *entries = NULL;
+	git_config_entries *dupped = NULL, *entries = NULL;
 	int error;

-	if ((error = config_refresh(backend)) < 0 ||
-	    (error = git_config_entries_dup(&entries, b->entries)) < 0 ||
-	    (error = git_config_entries_iterator_new(iter, entries)) < 0)
+	if ((error = config_file_refresh(backend)) < 0 ||
+	    (error = config_file_entries_take(&entries, b)) < 0 ||
+	    (error = git_config_entries_dup(&dupped, entries)) < 0 ||
+	    (error = git_config_entries_iterator_new(iter, dupped)) < 0)
 		goto out;

 out:
 	/* Let iterator delete duplicated entries when it's done */
 	git_config_entries_free(entries);
+	git_config_entries_free(dupped);
 	return error;
 }

-static int config_set(git_config_backend *cfg, const char *name, const char *value)
+static int config_file_snapshot(git_config_backend **out, git_config_backend *backend)
+{
+	return git_config_backend_snapshot(out, backend);
+}
+
+static int config_file_set(git_config_backend *cfg, const char *name, const char *value)
 {
 	config_file_backend *b = GIT_CONTAINER_OF(cfg, config_file_backend, parent);
 	git_config_entries *entries;
@@ -281,8 +282,8 @@ static int config_set(git_config_backend *cfg, const char *name, const char *val
 	if ((error = git_config__normalize_name(name, &key)) < 0)
 		return error;

-	if ((entries = diskfile_entries_take(b)) == NULL)
-		return -1;
+	if ((error = config_file_entries_take(&entries, b)) < 0)
+		return error;

 	/* Check whether we'd be modifying an included or multivar key */
 	if ((error = git_config_entries_get_unique(&existing, entries, key)) < 0) {
@@ -302,7 +303,7 @@ static int config_set(git_config_backend *cfg, const char *name, const char *val
 		GIT_ERROR_CHECK_ALLOC(esc_value);
 	}

-	if ((error = config_write(b, name, key, NULL, esc_value)) < 0)
+	if ((error = config_file_write(b, name, key, NULL, esc_value)) < 0)
 		goto out;

 out:
@@ -313,7 +314,7 @@ out:
 }

 /* release the map containing the entry as an equivalent to freeing it */
-static void free_diskfile_entry(git_config_entry *entry)
+static void config_file_entry_free(git_config_entry *entry)
 {
 	git_config_entries *entries = (git_config_entries *) entry->payload;
 	git_config_entries_free(entries);
@@ -322,32 +323,32 @@ static void free_diskfile_entry(git_config_entry *entry)
 /*
 * Internal function that actually gets the value in string form
 */
-static int config_get(git_config_backend *cfg, const char *key, git_config_entry **out)
+static int config_file_get(git_config_backend *cfg, const char *key, git_config_entry **out)
 {
 	config_file_backend *h = GIT_CONTAINER_OF(cfg, config_file_backend, parent);
 	git_config_entries *entries = NULL;
 	git_config_entry *entry;
 	int error = 0;

-	if (!h->parent.readonly && ((error = config_refresh(cfg)) < 0))
+	if (!h->parent.readonly && ((error = config_file_refresh(cfg)) < 0))
 		return error;

-	if ((entries = diskfile_entries_take(h)) == NULL)
-		return -1;
+	if ((error = config_file_entries_take(&entries, h)) < 0)
+		return error;

 	if ((error = (git_config_entries_get(&entry, entries, key))) < 0) {
 		git_config_entries_free(entries);
 		return error;
 	}

-	entry->free = free_diskfile_entry;
+	entry->free = config_file_entry_free;
 	entry->payload = entries;
 	*out = entry;

 	return 0;
 }

-static int config_set_multivar(
+static int config_file_set_multivar(
 	git_config_backend *cfg, const char *name, const char *regexp, const char *value)
 {
 	config_file_backend *b = GIT_CONTAINER_OF(cfg, config_file_backend, parent);
@@ -363,8 +364,8 @@ static int config_set_multivar(
 	if ((result = git_regexp_compile(&preg, regexp, 0)) < 0)
 		goto out;

-	/* If we do have it, set call config_write() and reload */
-	if ((result = config_write(b, name, key, &preg, value)) < 0)
+	/* If we do have it, set call config_file_write() and reload */
+	if ((result = config_file_write(b, name, key, &preg, value)) < 0)
 		goto out;

 out:
@@ -374,7 +375,7 @@ out:
 	return result;
 }

-static int config_delete(git_config_backend *cfg, const char *name)
+static int config_file_delete(git_config_backend *cfg, const char *name)
 {
 	config_file_backend *b = GIT_CONTAINER_OF(cfg, config_file_backend, parent);
 	git_config_entries *entries = NULL;
@@ -385,7 +386,7 @@ static int config_delete(git_config_backend *cfg, const char *name)
 	if ((error = git_config__normalize_name(name, &key)) < 0)
 		goto out;

-	if ((entries = diskfile_entries_take(b)) == NULL)
+	if ((error = config_file_entries_take(&entries, b)) < 0)
 		goto out;

 	/* Check whether we'd be modifying an included or multivar key */
@@ -395,7 +396,7 @@ static int config_delete(git_config_backend *cfg, const char *name)
 		goto out;
 	}

-	if ((error = config_write(b, name, entry->name, NULL, NULL)) < 0)
+	if ((error = config_file_write(b, name, entry->name, NULL, NULL)) < 0)
 		goto out;

 out:
@@ -404,7 +405,7 @@ out:
 	return error;
 }

-static int config_delete_multivar(git_config_backend *cfg, const char *name, const char *regexp)
+static int config_file_delete_multivar(git_config_backend *cfg, const char *name, const char *regexp)
 {
 	config_file_backend *b = GIT_CONTAINER_OF(cfg, config_file_backend, parent);
 	git_config_entries *entries = NULL;
@@ -416,10 +417,8 @@ static int config_delete_multivar(git_config_backend *cfg, const char *name, con
 	if ((result = git_config__normalize_name(name, &key)) < 0)
 		goto out;

-	if ((entries = diskfile_entries_take(b)) == NULL) {
-		result = -1;
+	if ((result = config_file_entries_take(&entries, b)) < 0)
 		goto out;
-	}

 	if ((result = git_config_entries_get(&entry, entries, key)) < 0) {
 		if (result == GIT_ENOTFOUND)
@@ -430,7 +429,7 @@ static int config_delete_multivar(git_config_backend *cfg, const char *name, con
 	if ((result = git_regexp_compile(&preg, regexp, 0)) < 0)
 		goto out;

-	if ((result = config_write(b, name, key, &preg, NULL)) < 0)
+	if ((result = config_file_write(b, name, key, &preg, NULL)) < 0)
 		goto out;

 out:
@@ -440,7 +439,7 @@ out:
 	return result;
 }

-static int config_lock(git_config_backend *_cfg)
+static int config_file_lock(git_config_backend *_cfg)
 {
 	config_file_backend *cfg = GIT_CONTAINER_OF(_cfg, config_file_backend, parent);
 	int error;
@@ -459,7 +458,7 @@ static int config_lock(git_config_backend *_cfg)

 }

-static int config_unlock(git_config_backend *_cfg, int success)
+static int config_file_unlock(git_config_backend *_cfg, int success)
 {
 	config_file_backend *cfg = GIT_CONTAINER_OF(_cfg, config_file_backend, parent);
 	int error = 0;
@@ -490,17 +489,17 @@ int git_config_backend_from_file(git_config_backend **out, const char *path)
 	GIT_ERROR_CHECK_ALLOC(backend->file.path);
 	git_array_init(backend->file.includes);

-	backend->parent.open = config_open;
-	backend->parent.get = config_get;
-	backend->parent.set = config_set;
-	backend->parent.set_multivar = config_set_multivar;
-	backend->parent.del = config_delete;
-	backend->parent.del_multivar = config_delete_multivar;
-	backend->parent.iterator = config_iterator_new;
-	backend->parent.snapshot = git_config_backend_snapshot;
-	backend->parent.lock = config_lock;
-	backend->parent.unlock = config_unlock;
-	backend->parent.free = backend_free;
+	backend->parent.open = config_file_open;
+	backend->parent.get = config_file_get;
+	backend->parent.set = config_file_set;
+	backend->parent.set_multivar = config_file_set_multivar;
+	backend->parent.del = config_file_delete;
+	backend->parent.del_multivar = config_file_delete_multivar;
+	backend->parent.iterator = config_file_iterator;
+	backend->parent.snapshot = config_file_snapshot;
+	backend->parent.lock = config_file_lock;
+	backend->parent.unlock = config_file_unlock;
+	backend->parent.free = config_file_free;

 	*out = (git_config_backend *)backend;

@@ -574,8 +573,8 @@ static int parse_include(config_file_parse_data *parse_data, const char *file)
 	git_array_init(include->includes);
 	include->path = git_buf_detach(&path);

-	result = config_read(parse_data->entries, parse_data->repo,
-		include, parse_data->level, parse_data->depth+1);
+	result = config_file_read(parse_data->entries, parse_data->repo, include,
+				  parse_data->level, parse_data->depth+1);

 	if (result == GIT_ENOTFOUND) {
 		git_error_clear();
@@ -793,7 +792,7 @@ static int read_on_variable(
 	return result;
 }

-static int config_read_buffer(
+static int config_file_read_buffer(
 	git_config_entries *entries,
 	const git_repository *repo,
 	config_file *file,
@@ -833,7 +832,7 @@ out:
 	return error;
 }

-static int config_read(
+static int config_file_read(
 	git_config_entries *entries,
 	const git_repository *repo,
 	config_file *file,
@@ -856,8 +855,8 @@ static int config_read(
 	if ((error = git_hash_buf(&file->checksum, contents.ptr, contents.size)) < 0)
 		goto out;

-	if ((error = config_read_buffer(entries, repo, file, level, depth,
-					contents.ptr, contents.size)) < 0)
+	if ((error = config_file_read_buffer(entries, repo, file, level, depth,
+					     contents.ptr, contents.size)) < 0)
 		goto out;

 out:
@@ -1088,7 +1087,7 @@ static int write_on_eof(
 /*
 * This is pretty much the parsing, except we write out anything we don't have
 */
-static int config_write(config_file_backend *cfg, const char *orig_key, const char *key, const git_regexp *preg, const char* value)
+static int config_file_write(config_file_backend *cfg, const char *orig_key, const char *key, const git_regexp *preg, const char* value)

 {
 	char *orig_section = NULL, *section = NULL, *orig_name, *name, *ldot;
@@ -1149,7 +1148,7 @@ static int config_write(config_file_backend *cfg, const char *orig_key, const ch
 		if ((error = git_filebuf_commit(&file)) < 0)
 			goto done;

-		if ((error = config_refresh_from_buffer(&cfg->parent, buf.ptr, buf.size)) < 0)
+		if ((error = config_file_refresh_from_buffer(&cfg->parent, buf.ptr, buf.size)) < 0)
 			goto done;
 	}

--- a/src/config_snapshot.c
+++ b/src/config_snapshot.c
@@ -22,7 +22,7 @@ static int config_error_readonly(void)
 	return -1;
 }

-static int config_iterator_new_readonly(
+static int config_snapshot_iterator(
 	git_config_iterator **iter,
 	struct git_config_backend *backend)
 {
@@ -41,13 +41,13 @@ out:
 }

 /* release the map containing the entry as an equivalent to freeing it */
-static void free_diskfile_entry(git_config_entry *entry)
+static void config_snapshot_entry_free(git_config_entry *entry)
 {
 	git_config_entries *entries = (git_config_entries *) entry->payload;
 	git_config_entries_free(entries);
 }

-static int config_get_readonly(git_config_backend *cfg, const char *key, git_config_entry **out)
+static int config_snapshot_get(git_config_backend *cfg, const char *key, git_config_entry **out)
 {
 	config_snapshot_backend *b = GIT_CONTAINER_OF(cfg, config_snapshot_backend, parent);
 	git_config_entries *entries = NULL;
@@ -68,14 +68,14 @@ static int config_get_readonly(git_config_backend *cfg, const char *key, git_con
 		return error;
 	}

-	entry->free = free_diskfile_entry;
+	entry->free = config_snapshot_entry_free;
 	entry->payload = entries;
 	*out = entry;

 	return 0;
 }

-static int config_set_readonly(git_config_backend *cfg, const char *name, const char *value)
+static int config_snapshot_set(git_config_backend *cfg, const char *name, const char *value)
 {
 	GIT_UNUSED(cfg);
 	GIT_UNUSED(name);
@@ -84,7 +84,7 @@ static int config_set_readonly(git_config_backend *cfg, const char *name, const
 	return config_error_readonly();
 }

-static int config_set_multivar_readonly(
+static int config_snapshot_set_multivar(
 	git_config_backend *cfg, const char *name, const char *regexp, const char *value)
 {
 	GIT_UNUSED(cfg);
@@ -95,7 +95,7 @@ static int config_set_multivar_readonly(
 	return config_error_readonly();
 }

-static int config_delete_multivar_readonly(git_config_backend *cfg, const char *name, const char *regexp)
+static int config_snapshot_delete_multivar(git_config_backend *cfg, const char *name, const char *regexp)
 {
 	GIT_UNUSED(cfg);
 	GIT_UNUSED(name);
@@ -104,7 +104,7 @@ static int config_delete_multivar_readonly(git_config_backend *cfg, const char *
 	return config_error_readonly();
 }

-static int config_delete_readonly(git_config_backend *cfg, const char *name)
+static int config_snapshot_delete(git_config_backend *cfg, const char *name)
 {
 	GIT_UNUSED(cfg);
 	GIT_UNUSED(name);
@@ -112,14 +112,14 @@ static int config_delete_readonly(git_config_backend *cfg, const char *name)
 	return config_error_readonly();
 }

-static int config_lock_readonly(git_config_backend *_cfg)
+static int config_snapshot_lock(git_config_backend *_cfg)
 {
 	GIT_UNUSED(_cfg);

 	return config_error_readonly();
 }

-static int config_unlock_readonly(git_config_backend *_cfg, int success)
+static int config_snapshot_unlock(git_config_backend *_cfg, int success)
 {
 	GIT_UNUSED(_cfg);
 	GIT_UNUSED(success);
@@ -127,7 +127,7 @@ static int config_unlock_readonly(git_config_backend *_cfg, int success)
 	return config_error_readonly();
 }

-static void backend_readonly_free(git_config_backend *_backend)
+static void config_snapshot_free(git_config_backend *_backend)
 {
 	config_snapshot_backend *backend = GIT_CONTAINER_OF(_backend, config_snapshot_backend, parent);

@@ -139,7 +139,7 @@ static void backend_readonly_free(git_config_backend *_backend)
 	git__free(backend);
 }

-static int config_readonly_open(git_config_backend *cfg, git_config_level_t level, const git_repository *repo)
+static int config_snapshot_open(git_config_backend *cfg, git_config_level_t level, const git_repository *repo)
 {
 	config_snapshot_backend *b = GIT_CONTAINER_OF(cfg, config_snapshot_backend, parent);
 	git_config_entries *entries = NULL;
@@ -188,17 +188,17 @@ int git_config_backend_snapshot(git_config_backend **out, git_config_backend *so

 	backend->parent.readonly = 1;
 	backend->parent.version = GIT_CONFIG_BACKEND_VERSION;
-	backend->parent.open = config_readonly_open;
-	backend->parent.get = config_get_readonly;
-	backend->parent.set = config_set_readonly;
-	backend->parent.set_multivar = config_set_multivar_readonly;
+	backend->parent.open = config_snapshot_open;
+	backend->parent.get = config_snapshot_get;
+	backend->parent.set = config_snapshot_set;
+	backend->parent.set_multivar = config_snapshot_set_multivar;
 	backend->parent.snapshot = git_config_backend_snapshot;
-	backend->parent.del = config_delete_readonly;
-	backend->parent.del_multivar = config_delete_multivar_readonly;
-	backend->parent.iterator = config_iterator_new_readonly;
-	backend->parent.lock = config_lock_readonly;
-	backend->parent.unlock = config_unlock_readonly;
-	backend->parent.free = backend_readonly_free;
+	backend->parent.del = config_snapshot_delete;
+	backend->parent.del_multivar = config_snapshot_delete_multivar;
+	backend->parent.iterator = config_snapshot_iterator;
+	backend->parent.lock = config_snapshot_lock;
+	backend->parent.unlock = config_snapshot_unlock;
+	backend->parent.free = config_snapshot_free;

 	*out = &backend->parent;