From 4598a99cf22de0dbab975d9c87ce16fd53146aca Mon Sep 17 00:00:00 2001 From: Joe Conway Date: Thu, 28 Feb 2019 15:57:40 -0500 Subject: [PATCH] Make get_controlfile not leak file descriptors When backend functions were added to expose controldata via SQL, reading of pg_control was consolidated under src/common so that both frontend and backend could share the same code. That move from frontend-only to shared frontend-backend failed to recognize the risk (and coding standards violation) of using a bare open(). In particular, it risked leaking file descriptors if transient errors occurred while reading the file. Fix that by using OpenTransientFile() instead in the backend case, which is purpose-built for this type of usage. Since there have been no complaints from the field, and an intermittent failure low risk, no backpatch. Hard failure would of course be bad, but in that case these functions are probably the least of your worries. Author: Joe Conway Reviewed-By: Michael Paquier Reported by: Michael Paquier Discussion: https://postgr.es/m/20190227074728.GA15710@paquier.xyz --- src/common/controldata_utils.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/src/common/controldata_utils.c b/src/common/controldata_utils.c index abfe7065f5..000f3c66d6 100644 --- a/src/common/controldata_utils.c +++ b/src/common/controldata_utils.c @@ -27,9 +27,12 @@ #include "catalog/pg_control.h" #include "common/controldata_utils.h" #include "port/pg_crc32c.h" +#ifndef FRONTEND +#include "storage/fd.h" +#endif /* - * get_controlfile(char *DataDir, const char *progname, bool *crc_ok_p) + * get_controlfile() * * Get controlfile values. The result is returned as a palloc'd copy of the * control file data. @@ -51,13 +54,14 @@ get_controlfile(const char *DataDir, const char *progname, bool *crc_ok_p) ControlFile = palloc(sizeof(ControlFileData)); snprintf(ControlFilePath, MAXPGPATH, "%s/global/pg_control", DataDir); - if ((fd = open(ControlFilePath, O_RDONLY | PG_BINARY, 0)) == -1) #ifndef FRONTEND + if ((fd = OpenTransientFile(ControlFilePath, O_RDONLY | PG_BINARY)) == -1) ereport(ERROR, (errcode_for_file_access(), errmsg("could not open file \"%s\" for reading: %m", ControlFilePath))); #else + if ((fd = open(ControlFilePath, O_RDONLY | PG_BINARY, 0)) == -1) { fprintf(stderr, _("%s: could not open file \"%s\" for reading: %s\n"), progname, ControlFilePath, strerror(errno)); @@ -95,7 +99,11 @@ get_controlfile(const char *DataDir, const char *progname, bool *crc_ok_p) #endif } +#ifndef FRONTEND + CloseTransientFile(fd); +#else close(fd); +#endif /* Check the CRC. */ INIT_CRC32C(crc); -- 2.40.0