From e7e005ed90f7e417696a9388717f91b55fd195bb Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Thu, 16 May 2013 15:04:38 -0400 Subject: [PATCH] Fix fd.c to preserve errno where needed. PathNameOpenFile failed to ensure that the correct value of errno was returned to its caller after a failure (because it incorrectly supposed that free() can never change errno). In some cases this would result in a user-visible failure because an expected ENOENT errno was replaced with something else. Bogus EINVAL failures have been observed on OS X, for example. There were also a couple of places that could mangle an important value of errno if FDDEBUG was defined. While the usefulness of that debug support is highly debatable, we might as well make it safe to use, so add errno save/restore logic to the DO_DB macro. Per bug #8167 from Nelson Minar, diagnosed by RhodiumToad. Back-patch to all supported branches. --- src/backend/storage/file/fd.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/src/backend/storage/file/fd.c b/src/backend/storage/file/fd.c index 4510ef32cb..b858cfc261 100644 --- a/src/backend/storage/file/fd.c +++ b/src/backend/storage/file/fd.c @@ -109,9 +109,15 @@ int max_safe_fds = 32; /* default if not changed */ /* Debugging.... */ #ifdef FDDEBUG -#define DO_DB(A) A +#define DO_DB(A) \ + do { \ + int _do_db_save_errno = errno; \ + A; \ + errno = _do_db_save_errno; \ + } while (0) #else -#define DO_DB(A) /* A */ +#define DO_DB(A) \ + ((void) 0) #endif #define VFD_CLOSED (-1) @@ -674,7 +680,7 @@ LruInsert(File file) if (vfdP->fd < 0) { DO_DB(elog(LOG, "RE_OPEN FAILED: %d", errno)); - return vfdP->fd; + return -1; } else { @@ -725,7 +731,7 @@ AllocateVfd(void) Index i; File file; - DO_DB(elog(LOG, "AllocateVfd. Size %lu", SizeVfdCache)); + DO_DB(elog(LOG, "AllocateVfd. Size %lu", (unsigned long) SizeVfdCache)); Assert(SizeVfdCache > 0); /* InitFileAccess not called? */ @@ -882,8 +888,11 @@ PathNameOpenFile(FileName fileName, int fileFlags, int fileMode) if (vfdP->fd < 0) { + int save_errno = errno; + FreeVfd(file); free(fnamecopy); + errno = save_errno; return -1; } ++nfile; -- 2.40.0