From patchwork Mon Jun 7 17:38:30 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Weimer X-Patchwork-Id: 43748 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 117F03893667 for ; Mon, 7 Jun 2021 17:43:30 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 117F03893667 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1623087810; bh=s3KbogsPPzVDoVkTj39RGI2FpGymf8EeH85Kn4CFoto=; h=To:Subject:In-Reply-To:References:Date:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To: From; b=T+d+2WrW3rMNkQbBKEjIA66WhBm+y54yCgKDzx0B8FlW959rH7oObWPZO7ad88tXL NNfSll/qCkUD7e074pkukWZOeel5VFDDHnSJJmVVqEfnLr/SZu3wQmSkh2/JWiaL/f 6KCkw0Spb99fFpc6wJd/zbdVCQPxByqRRKnAaKEM= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by sourceware.org (Postfix) with ESMTP id 37BB13938C37 for ; Mon, 7 Jun 2021 17:38:36 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 37BB13938C37 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-47--vT7Ic0GOEqwbmbTN7AzuA-1; Mon, 07 Jun 2021 13:38:34 -0400 X-MC-Unique: -vT7Ic0GOEqwbmbTN7AzuA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 27A901020C2E for ; Mon, 7 Jun 2021 17:38:33 +0000 (UTC) Received: from oldenburg.str.redhat.com (ovpn-115-60.ams2.redhat.com [10.36.115.60]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C5D9F60CC6 for ; Mon, 7 Jun 2021 17:38:31 +0000 (UTC) To: libc-alpha@sourceware.org Subject: [PATCH 6/8] nss_files: Add generic code for set*ent, end*ent and file open In-Reply-To: References: X-From-Line: 57ca5e485125e23e1adeeec22213d2871ed287e7 Mon Sep 17 00:00:00 2001 Message-Id: <57ca5e485125e23e1adeeec22213d2871ed287e7.1623085295.git.fweimer@redhat.com> Date: Mon, 07 Jun 2021 19:38:30 +0200 User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-Spam-Status: No, score=-12.5 required=5.0 tests=BAYES_00, DKIM_INVALID, DKIM_SIGNED, GIT_PATCH_0, KAM_DMARC_STATUS, KAM_SHORT, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H4, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Florian Weimer via Libc-alpha From: Florian Weimer Reply-To: Florian Weimer Errors-To: libc-alpha-bounces+patchwork=sourceware.org@sourceware.org Sender: "Libc-alpha" This reduces RSS usage if nss_files is not actually used, and can be used later to make NSS data thread-specific. It also results in a small code size reduction. Before: text data bss dec hex filename 2288 0 72 2360 938 nss/files-alias.os 1807 0 72 1879 757 nss/files-ethers.os 1371 0 72 1443 5a3 nss/files-grp.os 6246 0 72 6318 18ae nss/files-hosts.os 869 0 0 869 365 nss/files-initgroups.os 666 0 0 666 29a nss/files-init.os 1934 0 0 1934 78e nss/files-netgrp.os 2353 0 72 2425 979 nss/files-network.os 2130 0 72 2202 89a nss/files-proto.os 1372 0 72 1444 5a4 nss/files-pwd.os 2124 0 72 2196 894 nss/files-rpc.os 2265 0 72 2337 921 nss/files-service.os 1125 0 72 1197 4ad nss/files-sgrp.os 1124 0 72 1196 4ac nss/files-spwd.os After: text data bss dec hex filename 2040 0 0 2040 7f8 nss/files-alias.os 1599 0 0 1599 63f nss/files-ethers.os 1155 0 0 1155 483 nss/files-grp.os 6010 0 0 6010 177a nss/files-hosts.os 869 0 0 869 365 nss/files-initgroups.os 666 0 0 666 29a nss/files-init.os 1934 0 0 1934 78e nss/files-netgrp.os 2129 0 0 2129 851 nss/files-network.os 1914 0 0 1914 77a nss/files-proto.os 1156 0 0 1156 484 nss/files-pwd.os 1908 0 0 1908 774 nss/files-rpc.os 2057 0 0 2057 809 nss/files-service.os 909 0 0 909 38d nss/files-sgrp.os 908 0 0 908 38c nss/files-spwd.os 1090 0 8 1098 44a nss/nss_files_data.os 27674 code bytes before, 26344 code bytes after, so it is an overall win despite the extra initialization code. --- include/nss_files.h | 60 ++++++++++++++ nss/Makefile | 2 +- nss/Versions | 4 + nss/nss_files/files-XXX.c | 67 ++++----------- nss/nss_files/files-alias.c | 69 ++++------------ nss/nss_files/files-hosts.c | 4 +- nss/nss_files_data.c | 159 ++++++++++++++++++++++++++++++++++++ 7 files changed, 257 insertions(+), 108 deletions(-) create mode 100644 nss/nss_files_data.c diff --git a/include/nss_files.h b/include/nss_files.h index 6a0dcdb85b..7bf1951496 100644 --- a/include/nss_files.h +++ b/include/nss_files.h @@ -20,6 +20,9 @@ #define _NSS_FILES_H #include +#if IS_IN (libc) +#include +#endif /* Open PATH for reading, as a data source for nss_files. */ FILE *__nss_files_fopen (const char *path); @@ -47,6 +50,63 @@ int __nss_readline_seek (FILE *fp, off64_t offset) attribute_hidden; int __nss_parse_line_result (FILE *fp, off64_t offset, int parse_line_result); libc_hidden_proto (__nss_parse_line_result) +/* Per-file data. Used by the *ent functions that need to preserve + state across calls. */ +struct nss_files_per_file_data +{ + FILE *stream; +#if IS_IN (libc) + /* The size of locks changes between libc and nss_files, so this + member must be last and is only available in libc. */ + __libc_lock_define (, lock); +#endif +}; + +/* File index for __nss_files_data_get. */ +enum nss_files_file + { + nss_file_aliasent, + nss_file_etherent, + nss_file_grent, + nss_file_hostent, + nss_file_netent, + nss_file_protoent, + nss_file_pwent, + nss_file_rpcent, + nss_file_servent, + nss_file_sgent, + nss_file_spent, + + nss_file_count + }; + +/* Obtains a pointer to the per-file data for FILE, which is written + to *PDATA, and tries to open the file at PATH for it. On success, + returns NSS_STATUS_SUCCESS, and the caller must later call + __nss_files_data_put. On failure, NSS_STATUS_TRYAGAIN is returned, + and *ERRNOP and *HERRNOP are updated if these pointers are not + null. */ +enum nss_status __nss_files_data_open (struct nss_files_per_file_data **pdata, + enum nss_files_file file, + const char *path, + int *errnop, int *herrnop); +libc_hidden_proto (__nss_files_data_open) + +/* Unlock the per-file data, previously obtained by + __nss_files_data_open. */ +void __nss_files_data_put (struct nss_files_per_file_data *data); +libc_hidden_proto (__nss_files_data_put) + +/* Performs the set*ent operation for FILE. PATH is the file to + open. */ +enum nss_status __nss_files_data_setent (enum nss_files_file file, + const char *path); +libc_hidden_proto (__nss_files_data_setent) + +/* Performs the end*ent operation for FILE. */ +enum nss_status __nss_files_data_endent (enum nss_files_file file); +libc_hidden_proto (__nss_files_data_endent) + struct parser_data; /* Instances of the parse_line function from diff --git a/nss/Makefile b/nss/Makefile index 9682a31e20..271a0e7716 100644 --- a/nss/Makefile +++ b/nss/Makefile @@ -31,7 +31,7 @@ routines = nsswitch getnssent getnssent_r digits_dots \ compat-lookup nss_hash nss_files_fopen \ nss_readline nss_parse_line_result \ nss_fgetent_r nss_module nss_action \ - nss_action_parse nss_database + nss_action_parse nss_database nss_files_data # These are the databases that go through nss dispatch. # Caution: if you add a database here, you must add its real name diff --git a/nss/Versions b/nss/Versions index fdddea104c..7b040b4786 100644 --- a/nss/Versions +++ b/nss/Versions @@ -19,6 +19,10 @@ libc { __nss_services_lookup2; __nss_next2; __nss_lookup; __nss_hash; __nss_database_get; __nss_files_fopen; __nss_readline; __nss_parse_line_result; + __nss_files_data_endent; + __nss_files_data_open; + __nss_files_data_put; + __nss_files_data_setent; } } diff --git a/nss/nss_files/files-XXX.c b/nss/nss_files/files-XXX.c index b4b989d9bb..91553d7ca5 100644 --- a/nss/nss_files/files-XXX.c +++ b/nss/nss_files/files-XXX.c @@ -45,10 +45,12 @@ # include # define H_ERRNO_PROTO , int *herrnop # define H_ERRNO_ARG , herrnop +# define H_ERRNO_ARG_OR_NULL herrnop # define H_ERRNO_SET(val) (*herrnop = (val)) #else # define H_ERRNO_PROTO # define H_ERRNO_ARG +# define H_ERRNO_ARG_OR_NULL NULL # define H_ERRNO_SET(val) ((void) 0) #endif @@ -58,15 +60,11 @@ # define EXTRA_ARGS_VALUE #endif -/* Locks the static variables in this file. */ -__libc_lock_define_initialized (static, lock) /* Maintenance of the stream open on the database file. For getXXent operations the stream needs to be held open across calls, the other getXXbyYY operations all use their own stream. */ -static FILE *stream; - /* Open database file if not already opened. */ static enum nss_status internal_setent (FILE **stream) @@ -91,41 +89,13 @@ internal_setent (FILE **stream) enum nss_status CONCAT(_nss_files_set,ENTNAME) (int stayopen) { - enum nss_status status; - - __libc_lock_lock (lock); - - status = internal_setent (&stream); - - __libc_lock_unlock (lock); - - return status; -} - - -/* Close the database file. */ -static void -internal_endent (FILE **stream) -{ - if (*stream != NULL) - { - fclose (*stream); - *stream = NULL; - } + return __nss_files_data_setent (CONCAT (nss_file_, ENTNAME), DATAFILE); } - -/* Thread-safe, exported version of that. */ enum nss_status CONCAT(_nss_files_end,ENTNAME) (void) { - __libc_lock_lock (lock); - - internal_endent (&stream); - - __libc_lock_unlock (lock); - - return NSS_STATUS_SUCCESS; + return __nss_files_data_endent (CONCAT (nss_file_, ENTNAME)); } @@ -194,26 +164,19 @@ CONCAT(_nss_files_get,ENTNAME_r) (struct STRUCTURE *result, char *buffer, size_t buflen, int *errnop H_ERRNO_PROTO) { /* Return next entry in host file. */ - enum nss_status status = NSS_STATUS_SUCCESS; - - __libc_lock_lock (lock); - - /* Be prepared that the set*ent function was not called before. */ - if (stream == NULL) - { - int save_errno = errno; - - status = internal_setent (&stream); - - __set_errno (save_errno); - } - if (status == NSS_STATUS_SUCCESS) - status = internal_getent (stream, result, buffer, buflen, errnop - H_ERRNO_ARG EXTRA_ARGS_VALUE); + struct nss_files_per_file_data *data; + enum nss_status status = __nss_files_data_open (&data, + CONCAT (nss_file_, ENTNAME), + DATAFILE, + errnop, H_ERRNO_ARG_OR_NULL); + if (status != NSS_STATUS_SUCCESS) + return status; - __libc_lock_unlock (lock); + status = internal_getent (data->stream, result, buffer, buflen, errnop + H_ERRNO_ARG EXTRA_ARGS_VALUE); + __nss_files_data_put (data); return status; } @@ -248,7 +211,7 @@ _nss_files_get##name##_r (proto, \ == NSS_STATUS_SUCCESS) \ { break_if_match } \ \ - internal_endent (&stream); \ + fclose (stream); \ } \ \ return status; \ diff --git a/nss/nss_files/files-alias.c b/nss/nss_files/files-alias.c index 30971bfe56..9624b6224c 100644 --- a/nss/nss_files/files-alias.c +++ b/nss/nss_files/files-alias.c @@ -33,16 +33,11 @@ NSS_DECLARE_MODULE_FUNCTIONS (files) -/* Locks the static variables in this file. */ -__libc_lock_define_initialized (static, lock) /* Maintenance of the stream open on the database file. For getXXent operations the stream needs to be held open across calls, the other getXXbyYY operations all use their own stream. */ -static FILE *stream; - - static enum nss_status internal_setent (FILE **stream) { @@ -66,41 +61,13 @@ internal_setent (FILE **stream) enum nss_status _nss_files_setaliasent (void) { - enum nss_status status; - - __libc_lock_lock (lock); - - status = internal_setent (&stream); - - __libc_lock_unlock (lock); - - return status; -} - - -/* Close the database file. */ -static void -internal_endent (FILE **stream) -{ - if (*stream != NULL) - { - fclose (*stream); - *stream = NULL; - } + return __nss_files_data_setent (nss_file_aliasent, "/etc/aliases"); } - -/* Thread-safe, exported version of that. */ enum nss_status _nss_files_endaliasent (void) { - __libc_lock_lock (lock); - - internal_endent (&stream); - - __libc_lock_unlock (lock); - - return NSS_STATUS_SUCCESS; + return __nss_files_data_endent (nss_file_aliasent); } /* Parsing the database file into `struct aliasent' data structures. */ @@ -369,26 +336,22 @@ _nss_files_getaliasent_r (struct aliasent *result, char *buffer, size_t buflen, int *errnop) { /* Return next entry in host file. */ - enum nss_status status = NSS_STATUS_SUCCESS; - __libc_lock_lock (lock); + struct nss_files_per_file_data *data; + enum nss_status status = __nss_files_data_open (&data, nss_file_aliasent, + "/etc/aliases", errnop, NULL); + if (status != NSS_STATUS_SUCCESS) + return status; - /* Be prepared that the set*ent function was not called before. */ - if (stream == NULL) - status = internal_setent (&stream); + result->alias_local = 1; - if (status == NSS_STATUS_SUCCESS) - { - result->alias_local = 1; - - /* Read lines until we get a definite result. */ - do - status = get_next_alias (stream, NULL, result, buffer, buflen, errnop); - while (status == NSS_STATUS_RETURN); - } - - __libc_lock_unlock (lock); + /* Read lines until we get a definite result. */ + do + status = get_next_alias (data->stream, NULL, result, buffer, buflen, + errnop); + while (status == NSS_STATUS_RETURN); + __nss_files_data_put (data); return status; } @@ -418,9 +381,9 @@ _nss_files_getaliasbyname_r (const char *name, struct aliasent *result, do status = get_next_alias (stream, name, result, buffer, buflen, errnop); while (status == NSS_STATUS_RETURN); - } - internal_endent (&stream); + fclose (stream); + } return status; } diff --git a/nss/nss_files/files-hosts.c b/nss/nss_files/files-hosts.c index 2b47ec3e53..1dd51d1db9 100644 --- a/nss/nss_files/files-hosts.c +++ b/nss/nss_files/files-hosts.c @@ -349,7 +349,7 @@ _nss_files_gethostbyname3_r (const char *name, int af, struct hostent *result, status = gethostbyname3_multi (stream, name, af, result, buffer, buflen, errnop, herrnop); - internal_endent (&stream); + fclose (stream); } if (canonp && status == NSS_STATUS_SUCCESS) @@ -475,7 +475,7 @@ _nss_files_gethostbyname4_r (const char *name, struct gaih_addrtuple **pat, status = NSS_STATUS_SUCCESS; } - internal_endent (&stream); + fclose (stream); } else if (status == NSS_STATUS_TRYAGAIN) { diff --git a/nss/nss_files_data.c b/nss/nss_files_data.c new file mode 100644 index 0000000000..7b7662abf1 --- /dev/null +++ b/nss/nss_files_data.c @@ -0,0 +1,159 @@ +/* Returns a pointer to the global nss_files data structure. + Copyright (C) 2021 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include + +#include +#include +#include +#include +#include + +/* This collects all per file-data. */ +struct nss_files_data +{ + struct nss_files_per_file_data files[nss_file_count]; +}; + +/* For use with allocate_once. */ +static void *nss_files_global; +static void * +nss_files_global_allocate (void *closure) +{ + struct nss_files_data *result = malloc (sizeof (*result)); + if (result != NULL) + for (int i = 0; i < nss_file_count; ++i) + { + result->files[i].stream = NULL; + __libc_lock_init (result->files[i].lock); + } + return result; +} +/* Like __nss_files_data_open, but does not perform the open call. */ +static enum nss_status +__nss_files_data_get (struct nss_files_per_file_data **pdata, + enum nss_files_file file, int *errnop, int *herrnop) +{ + struct nss_files_data *data = allocate_once (&nss_files_global, + nss_files_global_allocate, + NULL, NULL); + if (data == NULL) + { + if (errnop != NULL) + *errnop = errno; + if (herrnop != NULL) + { + __set_h_errno (NETDB_INTERNAL); + *herrnop = NETDB_INTERNAL; + } + return NSS_STATUS_TRYAGAIN; + } + + *pdata = &data->files[file]; + __libc_lock_lock ((*pdata)->lock); + return NSS_STATUS_SUCCESS; +} + +/* Helper function for opening the backing file at PATH. */ +static enum nss_status +__nss_files_data_internal_open (struct nss_files_per_file_data *data, + const char *path) +{ + enum nss_status status = NSS_STATUS_SUCCESS; + + if (data->stream == NULL) + { + data->stream = __nss_files_fopen (path); + + if (data->stream == NULL) + status = errno == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL; + } + + return status; +} + + +enum nss_status +__nss_files_data_open (struct nss_files_per_file_data **pdata, + enum nss_files_file file, const char *path, + int *errnop, int *herrnop) +{ + enum nss_status status = __nss_files_data_get (pdata, file, errnop, herrnop); + if (status != NSS_STATUS_SUCCESS) + return status; + + /* Be prepared that the set*ent function was not called before. */ + if ((*pdata)->stream == NULL) + { + int saved_errno = errno; + status = __nss_files_data_internal_open (*pdata, path); + __set_errno (saved_errno); + if (status != NSS_STATUS_SUCCESS) + __nss_files_data_put (*pdata); + } + + return status; +} + +libc_hidden_def (__nss_files_data_open) + +void +__nss_files_data_put (struct nss_files_per_file_data *data) +{ + __libc_lock_unlock (data->lock); +} +libc_hidden_def (__nss_files_data_put) + +enum nss_status +__nss_files_data_setent (enum nss_files_file file, const char *path) +{ + struct nss_files_per_file_data *data; + enum nss_status status = __nss_files_data_get (&data, file, NULL, NULL); + if (status != NSS_STATUS_SUCCESS) + return status; + + if (data->stream == NULL) + status = __nss_files_data_internal_open (data, path); + else + rewind (data->stream); + + __nss_files_data_put (data); + return status; +} +libc_hidden_def (__nss_files_data_setent) + +enum nss_status +__nss_files_data_endent (enum nss_files_file file) +{ + /* No cleanup is necessary if not initialized. */ + struct nss_files_data *data = atomic_load_acquire (&nss_files_global); + if (data == NULL) + return NSS_STATUS_SUCCESS; + + struct nss_files_per_file_data *fdata = &data->files[file]; + __libc_lock_lock (fdata->lock); + if (fdata->stream != NULL) + { + fclose (fdata->stream); + fdata->stream = NULL; + } + __libc_lock_unlock (fdata->lock); + + return NSS_STATUS_SUCCESS; +} +libc_hidden_def (__nss_files_data_endent)