reftable/stack: adapt `stack_filename()` to handle allocation failures
The `stack_filename()` function cannot pass any errors to the caller as it has a `void` return type. Adapt it and its callers such that we can handle errors and start handling allocation failures. There are two interesting edge cases in `reftable_stack_destroy()` and `reftable_addition_close()`. Both of these are trying to tear down their respective structures, and while doing so they try to unlink some of the tables they have been keeping alive. Any earlier attempts to do that may fail on Windows because it keeps us from deleting such tables while they are still open, and thus we re-try on close. It's okay and even expected that this can fail when the tables are still open by another process, so we handle the allocation failures gracefully and just skip over any file whose name we couldn't figure out. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Taylor Blau <me@ttaylorr.com>
Patrick Steinhardt committed
Oct 17, 2024 at 06:54 UTC
591c6a600e0ef1bfc71d66d74b64bf47de62fc8e
1 file changed
+45
-17
reftable/stack.c
+45
-17
@@ -31,13 +31,16 @@ static void reftable_addition_close(struct reftable_addition *add);
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static int reftable_stack_reload_maybe_reuse(struct reftable_stack *st,
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int reuse_open);
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-static void stack_filename(struct reftable_buf *dest, struct reftable_stack *st,
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- const char *name)
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+static int stack_filename(struct reftable_buf *dest, struct reftable_stack *st,
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+ const char *name)
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{
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+ int err;
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reftable_buf_reset(dest);
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- reftable_buf_addstr(dest, st->reftable_dir);
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- reftable_buf_addstr(dest, "/");
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- reftable_buf_addstr(dest, name);
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+ if ((err = reftable_buf_addstr(dest, st->reftable_dir)) < 0 ||
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+ (err = reftable_buf_addstr(dest, "/")) < 0 ||
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+ (err = reftable_buf_addstr(dest, name)) < 0)
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+ return err;
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+ return 0;
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}
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static ssize_t reftable_fd_write(void *arg, const void *data, size_t sz)
@@ -211,13 +214,16 @@ void reftable_stack_destroy(struct reftable_stack *st)
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struct reftable_buf filename = REFTABLE_BUF_INIT;
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for (i = 0; i < st->readers_len; i++) {
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const char *name = reader_name(st->readers[i]);
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+ int try_unlinking = 1;
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+
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reftable_buf_reset(&filename);
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if (names && !has_name(names, name)) {
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- stack_filename(&filename, st, name);
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+ if (stack_filename(&filename, st, name) < 0)
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+ try_unlinking = 0;
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}
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reftable_reader_decref(st->readers[i]);
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- if (filename.len) {
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+ if (try_unlinking && filename.len) {
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/* On Windows, can only unlink after closing. */
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unlink(filename.buf);
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}
@@ -310,7 +316,10 @@ static int reftable_stack_reload_once(struct reftable_stack *st,
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if (!rd) {
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struct reftable_block_source src = { NULL };
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- stack_filename(&table_path, st, name);
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+
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+ err = stack_filename(&table_path, st, name);
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+ if (err < 0)
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+ goto done;
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err = reftable_block_source_from_file(&src,
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table_path.buf);
@@ -341,7 +350,11 @@ static int reftable_stack_reload_once(struct reftable_stack *st,
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for (i = 0; i < cur_len; i++) {
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if (cur[i]) {
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const char *name = reader_name(cur[i]);
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- stack_filename(&table_path, st, name);
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+
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+ err = stack_filename(&table_path, st, name);
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+ if (err < 0)
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+ goto done;
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+
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reftable_reader_decref(cur[i]);
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unlink(table_path.buf);
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}
@@ -700,8 +713,8 @@ static void reftable_addition_close(struct reftable_addition *add)
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size_t i;
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for (i = 0; i < add->new_tables_len; i++) {
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- stack_filename(&nm, add->stack, add->new_tables[i]);
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- unlink(nm.buf);
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+ if (!stack_filename(&nm, add->stack, add->new_tables[i]))
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+ unlink(nm.buf);
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reftable_free(add->new_tables[i]);
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add->new_tables[i] = NULL;
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}
@@ -851,7 +864,9 @@ int reftable_addition_add(struct reftable_addition *add,
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if (err < 0)
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goto done;
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854
- stack_filename(&temp_tab_file_name, add->stack, next_name.buf);
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+ err = stack_filename(&temp_tab_file_name, add->stack, next_name.buf);
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+ if (err < 0)
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+ goto done;
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reftable_buf_addstr(&temp_tab_file_name, ".temp.XXXXXX");
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tab_file = mks_tempfile(temp_tab_file_name.buf);
@@ -900,7 +915,10 @@ int reftable_addition_add(struct reftable_addition *add,
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if (err < 0)
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goto done;
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reftable_buf_addstr(&next_name, ".ref");
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- stack_filename(&tab_file_name, add->stack, next_name.buf);
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+
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+ err = stack_filename(&tab_file_name, add->stack, next_name.buf);
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+ if (err < 0)
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+ goto done;
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/*
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On windows, this relies on rand() picking a unique destination name.
@@ -954,7 +972,9 @@ static int stack_compact_locked(struct reftable_stack *st,
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if (err < 0)
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goto done;
974
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- stack_filename(&tab_file_path, st, next_name.buf);
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+ err = stack_filename(&tab_file_path, st, next_name.buf);
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+ if (err < 0)
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+ goto done;
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reftable_buf_addstr(&tab_file_path, ".temp.XXXXXX");
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tab_file = mks_tempfile(tab_file_path.buf);
@@ -1174,7 +1194,9 @@ static int stack_compact_range(struct reftable_stack *st,
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}
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for (i = last + 1; i > first; i--) {
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- stack_filename(&table_name, st, reader_name(st->readers[i - 1]));
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+ err = stack_filename(&table_name, st, reader_name(st->readers[i - 1]));
1198
+ if (err < 0)
1199
+ goto done;
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err = hold_lock_file_for_update(&table_locks[nlocks],
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table_name.buf, LOCK_NO_DEREF);
@@ -1383,7 +1405,10 @@ static int stack_compact_range(struct reftable_stack *st,
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goto done;
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reftable_buf_addstr(&new_table_name, ".ref");
1386
- stack_filename(&new_table_path, st, new_table_name.buf);
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+
1409
+ err = stack_filename(&new_table_path, st, new_table_name.buf);
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+ if (err < 0)
1411
+ goto done;
1412
1413
err = rename_tempfile(&new_table, new_table_path.buf);
1414
if (err < 0) {
@@ -1677,7 +1702,10 @@ static void remove_maybe_stale_table(struct reftable_stack *st, uint64_t max,
1702
struct reftable_block_source src = { NULL };
1703
struct reftable_reader *rd = NULL;
1704
struct reftable_buf table_path = REFTABLE_BUF_INIT;
1680
- stack_filename(&table_path, st, name);
1705
+
1706
+ err = stack_filename(&table_path, st, name);
1707
+ if (err < 0)
1708
+ goto done;
1709
1710
err = reftable_block_source_from_file(&src, table_path.buf);
1711
if (err < 0)