From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: Florian Weimer <fweimer@redhat.com>, libc-alpha@sourceware.org
Subject: Re: [PATCH 7/7] nss: Access nss_files through direct references
Date: Wed, 7 Jul 2021 10:49:40 -0300 [thread overview]
Message-ID: <c064c087-6be4-91b5-042c-f530f2d8d48b@linaro.org> (raw)
In-Reply-To: <a11b3386cbab6622b6a19fda20090c8ab5fd3a7b.1624961355.git.fweimer@redhat.com>
On 29/06/2021 07:11, Florian Weimer via Libc-alpha wrote:
> This partially fixes static-only NSS support (bug 27959): The files
> module no longer needs dlopen. Support for the dns module remains
> to be added, and also support for disabling dlopen altogher.
s/altogher/altogether
LGTM, only a minor nit below.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
> ---
> include/nss_files.h | 10 ++++++++
> nss/Makefile | 3 ++-
> nss/nss_files/files-XXX.c | 6 ++++-
> nss/nss_files/files-alias.c | 7 +++---
> nss/nss_files/files-ethers.c | 2 --
> nss/nss_files/files-grp.c | 2 --
> nss/nss_files/files-hosts.c | 6 +++--
> nss/nss_files/files-init.c | 4 +--
> nss/nss_files/files-initgroups.c | 3 +--
> nss/nss_files/files-netgrp.c | 5 ++--
> nss/nss_files/files-network.c | 1 -
> nss/nss_files/files-proto.c | 2 --
> nss/nss_files/files-pwd.c | 2 --
> nss/nss_files/files-rpc.c | 2 --
> nss/nss_files/files-service.c | 2 --
> nss/nss_files/files-sgrp.c | 2 --
> nss/nss_files/files-spwd.c | 2 --
> nss/nss_files_functions.c | 43 ++++++++++++++++++++++++++++++++
> nss/nss_module.c | 38 +++++++++++++++++++++++++++-
> nss/nss_module.h | 4 +++
> 20 files changed, 114 insertions(+), 32 deletions(-)
> create mode 100644 nss/nss_files_functions.c
>
> diff --git a/include/nss_files.h b/include/nss_files.h
> index dd0081a0f1..6190cac6be 100644
> --- a/include/nss_files.h
> +++ b/include/nss_files.h
> @@ -19,6 +19,7 @@
> #ifndef _NSS_FILES_H
> #define _NSS_FILES_H
>
> +#include <nss.h>
> #include <stdio.h>
> #if IS_IN (libc)
> #include <libc-lock.h>
> @@ -134,6 +135,15 @@ libc_hidden_proto (_nss_files_parse_servent)
> libc_hidden_proto (_nss_files_parse_sgent)
> libc_hidden_proto (_nss_files_parse_spent)
>
> +NSS_DECLARE_MODULE_FUNCTIONS (files)
> +#undef DEFINE_NSS_FUNCTION
> +#define DEFINE_NSS_FUNCTION(x) libc_hidden_proto (_nss_files_##x)
> +#include <nss/function.def>
> +#undef DEFINE_NSS_FUNCTION
> +
> +void _nss_files_init (void (*cb) (size_t, struct traced_file *));
> +libc_hidden_proto (_nss_files_init)
> +
> /* Generic implementation of fget*ent_r. Reads lines from FP until
> EOF or a successful parse into *RESULT using PARSER. Returns 0 on
> success, ENOENT on EOF, ERANGE on too-small buffer. */
Ok.
> diff --git a/nss/Makefile b/nss/Makefile
> index 8905a5fd9b..75afb22cb3 100644
> --- a/nss/Makefile
> +++ b/nss/Makefile
> @@ -31,7 +31,8 @@ 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_files_data
> + nss_action_parse nss_database nss_files_data \
> + nss_files_functions
>
> # These are the databases that go through nss dispatch.
> # Caution: if you add a database here, you must add its real name
Maybe add one entry per line here?
> diff --git a/nss/nss_files/files-XXX.c b/nss/nss_files/files-XXX.c
> index 91553d7ca5..c158a891bd 100644
> --- a/nss/nss_files/files-XXX.c
> +++ b/nss/nss_files/files-XXX.c
> @@ -91,12 +91,14 @@ CONCAT(_nss_files_set,ENTNAME) (int stayopen)
> {
> return __nss_files_data_setent (CONCAT (nss_file_, ENTNAME), DATAFILE);
> }
> +libc_hidden_def (CONCAT (_nss_files_set,ENTNAME))
>
> enum nss_status
> CONCAT(_nss_files_end,ENTNAME) (void)
> {
> return __nss_files_data_endent (CONCAT (nss_file_, ENTNAME));
> }
> +libc_hidden_def (CONCAT (_nss_files_end,ENTNAME))
> \f
>
> /* Parsing the database file into `struct STRUCTURE' data structures. */
> @@ -179,6 +181,7 @@ CONCAT(_nss_files_get,ENTNAME_r) (struct STRUCTURE *result, char *buffer,
> __nss_files_data_put (data);
> return status;
> }
> +libc_hidden_def (CONCAT (_nss_files_get,ENTNAME_r))
> \f
> /* Macro for defining lookup functions for this file-based database.
>
> @@ -215,4 +218,5 @@ _nss_files_get##name##_r (proto, \
> } \
> \
> return status; \
> -}
> +} \
> +libc_hidden_def (_nss_files_get##name##_r)
Ok.
> diff --git a/nss/nss_files/files-alias.c b/nss/nss_files/files-alias.c
> index 75d91e0b0a..8c6e176ff6 100644
> --- a/nss/nss_files/files-alias.c
> +++ b/nss/nss_files/files-alias.c
> @@ -31,8 +31,6 @@
> #include "nsswitch.h"
> #include <nss_files.h>
>
> -NSS_DECLARE_MODULE_FUNCTIONS (files)
> -
> \f
> /* Maintenance of the stream open on the database file. For getXXent
> operations the stream needs to be held open across calls, the other
> @@ -63,12 +61,14 @@ _nss_files_setaliasent (void)
> {
> return __nss_files_data_setent (nss_file_aliasent, "/etc/aliases");
> }
> +libc_hidden_def (_nss_files_setaliasent)
>
> enum nss_status
> _nss_files_endaliasent (void)
> {
> return __nss_files_data_endent (nss_file_aliasent);
> }
> +libc_hidden_def (_nss_files_endaliasent)
> \f
> /* Parsing the database file into `struct aliasent' data structures. */
> static enum nss_status
> @@ -354,7 +354,7 @@ _nss_files_getaliasent_r (struct aliasent *result, char *buffer, size_t buflen,
> __nss_files_data_put (data);
> return status;
> }
> -
> +libc_hidden_def (_nss_files_getaliasent_r)
>
> enum nss_status
> _nss_files_getaliasbyname_r (const char *name, struct aliasent *result,
> @@ -387,3 +387,4 @@ _nss_files_getaliasbyname_r (const char *name, struct aliasent *result,
>
> return status;
> }
> +libc_hidden_def (_nss_files_getaliasbyname_r)
Ok.
> diff --git a/nss/nss_files/files-ethers.c b/nss/nss_files/files-ethers.c
> index 2fe7f81e4b..7c2c2b9833 100644
> --- a/nss/nss_files/files-ethers.c
> +++ b/nss/nss_files/files-ethers.c
> @@ -20,8 +20,6 @@
> #include <netinet/if_ether.h>
> #include <nss.h>
>
> -NSS_DECLARE_MODULE_FUNCTIONS (files)
> -
> struct etherent_data {};
>
> #define ENTNAME etherent
Ok.
> diff --git a/nss/nss_files/files-grp.c b/nss/nss_files/files-grp.c
> index 49be38e8b1..a716d948e2 100644
> --- a/nss/nss_files/files-grp.c
> +++ b/nss/nss_files/files-grp.c
> @@ -19,8 +19,6 @@
> #include <grp.h>
> #include <nss.h>
>
> -NSS_DECLARE_MODULE_FUNCTIONS (files)
> -
> #define STRUCTURE group
> #define ENTNAME grent
> #define DATABASE "group"
Ok.
> diff --git a/nss/nss_files/files-hosts.c b/nss/nss_files/files-hosts.c
> index 894b85d501..d54d91d038 100644
> --- a/nss/nss_files/files-hosts.c
> +++ b/nss/nss_files/files-hosts.c
> @@ -26,8 +26,6 @@
> #include <alloc_buffer.h>
> #include <nss.h>
>
> -NSS_DECLARE_MODULE_FUNCTIONS (files)
> -
> /* Get implementation for some internal functions. */
> #include "../resolv/res_hconf.h"
>
> @@ -358,6 +356,7 @@ _nss_files_gethostbyname3_r (const char *name, int af, struct hostent *result,
>
> return status;
> }
> +libc_hidden_def (_nss_files_gethostbyname3_r)
>
> enum nss_status
> _nss_files_gethostbyname_r (const char *name, struct hostent *result,
> @@ -367,6 +366,7 @@ _nss_files_gethostbyname_r (const char *name, struct hostent *result,
> return _nss_files_gethostbyname3_r (name, AF_INET, result, buffer, buflen,
> errnop, herrnop, NULL, NULL);
> }
> +libc_hidden_def (_nss_files_gethostbyname_r)
>
> enum nss_status
> _nss_files_gethostbyname2_r (const char *name, int af, struct hostent *result,
> @@ -376,6 +376,7 @@ _nss_files_gethostbyname2_r (const char *name, int af, struct hostent *result,
> return _nss_files_gethostbyname3_r (name, af, result, buffer, buflen,
> errnop, herrnop, NULL, NULL);
> }
> +libc_hidden_def (_nss_files_gethostbyname2_r)
>
> enum nss_status
> _nss_files_gethostbyname4_r (const char *name, struct gaih_addrtuple **pat,
> @@ -491,3 +492,4 @@ _nss_files_gethostbyname4_r (const char *name, struct gaih_addrtuple **pat,
>
> return status;
> }
> +libc_hidden_def (_nss_files_gethostbyname4_r)
Ok.
> diff --git a/nss/nss_files/files-init.c b/nss/nss_files/files-init.c
> index 36d5ebce1f..18d48168e8 100644
> --- a/nss/nss_files/files-init.c
> +++ b/nss/nss_files/files-init.c
> @@ -21,8 +21,7 @@
> #include <string.h>
> #include <nscd/nscd.h>
> #include <nss.h>
> -
> -NSS_DECLARE_MODULE_FUNCTIONS (files)
> +#include <nss_files.h>
>
> static void
> register_file (void (*cb) (size_t, struct traced_file *),
> @@ -49,5 +48,6 @@ _nss_files_init (void (*cb) (size_t, struct traced_file *))
> register_file (cb, servdb, "/etc/services", 0);
> register_file (cb, netgrdb, "/etc/netgroup", 0);
> }
> +libc_hidden_def (_nss_files_init)
>
> #endif
Ok.
> diff --git a/nss/nss_files/files-initgroups.c b/nss/nss_files/files-initgroups.c
> index 6fcea40b55..b44211e50b 100644
> --- a/nss/nss_files/files-initgroups.c
> +++ b/nss/nss_files/files-initgroups.c
> @@ -28,8 +28,6 @@
> #include <nss.h>
> #include <nss_files.h>
>
> -NSS_DECLARE_MODULE_FUNCTIONS (files)
> -
> enum nss_status
> _nss_files_initgroups_dyn (const char *user, gid_t group, long int *start,
> long int *size, gid_t **groupsp, long int limit,
> @@ -129,3 +127,4 @@ _nss_files_initgroups_dyn (const char *user, gid_t group, long int *start,
>
> return status == NSS_STATUS_SUCCESS && !any ? NSS_STATUS_NOTFOUND : status;
> }
> +libc_hidden_def (_nss_files_initgroups_dyn)
Ok.
> diff --git a/nss/nss_files/files-netgrp.c b/nss/nss_files/files-netgrp.c
> index be9c72accf..75bfbd9e44 100644
> --- a/nss/nss_files/files-netgrp.c
> +++ b/nss/nss_files/files-netgrp.c
> @@ -28,8 +28,6 @@
> #include "netgroup.h"
> #include <nss_files.h>
>
> -NSS_DECLARE_MODULE_FUNCTIONS (files)
> -
> #define DATAFILE "/etc/netgroup"
>
> libc_hidden_proto (_nss_files_endnetgrent)
> @@ -152,7 +150,7 @@ _nss_files_setnetgrent (const char *group, struct __netgrent *result)
>
> return status;
> }
> -
> +libc_hidden_def (_nss_files_setnetgrent)
>
> enum nss_status
> _nss_files_endnetgrent (struct __netgrent *result)
> @@ -293,3 +291,4 @@ _nss_files_getnetgrent_r (struct __netgrent *result, char *buffer,
>
> return status;
> }
> +libc_hidden_def (_nss_files_getnetgrent_r)
Ok.
> diff --git a/nss/nss_files/files-network.c b/nss/nss_files/files-network.c
> index 75c9f8a57e..217ed78609 100644
> --- a/nss/nss_files/files-network.c
> +++ b/nss/nss_files/files-network.c
> @@ -21,7 +21,6 @@
> #include <netdb.h>
> #include <stdint.h>
> #include <nss.h>
> -#include <nss_files.h>
>
> #define ENTNAME netent
> #define DATABASE "networks"
Ok.
> diff --git a/nss/nss_files/files-proto.c b/nss/nss_files/files-proto.c
> index 98d082c642..13072692c1 100644
> --- a/nss/nss_files/files-proto.c
> +++ b/nss/nss_files/files-proto.c
> @@ -19,8 +19,6 @@
> #include <netdb.h>
> #include <nss.h>
>
> -NSS_DECLARE_MODULE_FUNCTIONS (files)
> -
> #define ENTNAME protoent
> #define DATABASE "protocols"
>
Ok.
> diff --git a/nss/nss_files/files-pwd.c b/nss/nss_files/files-pwd.c
> index b04165ddde..5c74c6da9b 100644
> --- a/nss/nss_files/files-pwd.c
> +++ b/nss/nss_files/files-pwd.c
> @@ -19,8 +19,6 @@
> #include <pwd.h>
> #include <nss.h>
>
> -NSS_DECLARE_MODULE_FUNCTIONS (files)
> -
> #define STRUCTURE passwd
> #define ENTNAME pwent
> #define DATABASE "passwd"
Ok.
> diff --git a/nss/nss_files/files-rpc.c b/nss/nss_files/files-rpc.c
> index eeb2725d2c..3dea8f18f2 100644
> --- a/nss/nss_files/files-rpc.c
> +++ b/nss/nss_files/files-rpc.c
> @@ -19,8 +19,6 @@
> #include <rpc/netdb.h>
> #include <nss.h>
>
> -NSS_DECLARE_MODULE_FUNCTIONS (files)
> -
> #define ENTNAME rpcent
> #define DATABASE "rpc"
>
Ok.
> diff --git a/nss/nss_files/files-service.c b/nss/nss_files/files-service.c
> index f4f0985377..a8d83e094e 100644
> --- a/nss/nss_files/files-service.c
> +++ b/nss/nss_files/files-service.c
> @@ -20,8 +20,6 @@
> #include <netdb.h>
> #include <nss.h>
>
> -NSS_DECLARE_MODULE_FUNCTIONS (files)
> -
> #define ENTNAME servent
> #define DATABASE "services"
>
Ok.
> diff --git a/nss/nss_files/files-sgrp.c b/nss/nss_files/files-sgrp.c
> index 6b1c9eac02..213a408e7b 100644
> --- a/nss/nss_files/files-sgrp.c
> +++ b/nss/nss_files/files-sgrp.c
> @@ -19,8 +19,6 @@
> #include <gshadow.h>
> #include <nss.h>
>
> -NSS_DECLARE_MODULE_FUNCTIONS (files)
> -
> #define STRUCTURE sgrp
> #define ENTNAME sgent
> #define DATABASE "gshadow"
> diff --git a/nss/nss_files/files-spwd.c b/nss/nss_files/files-spwd.c
> index 976deaf918..d031257a20 100644
> --- a/nss/nss_files/files-spwd.c
> +++ b/nss/nss_files/files-spwd.c
> @@ -19,8 +19,6 @@
> #include <shadow.h>
> #include <nss.h>
>
> -NSS_DECLARE_MODULE_FUNCTIONS (files)
> -
> #define STRUCTURE spwd
> #define ENTNAME spent
> #define DATABASE "shadow"
Ok.
> diff --git a/nss/nss_files_functions.c b/nss/nss_files_functions.c
> new file mode 100644
> index 0000000000..85720b4311
> --- /dev/null
> +++ b/nss/nss_files_functions.c
> @@ -0,0 +1,43 @@
> +/* Direct access for nss_files functions for NSS module loading.
> + 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
> + <https://www.gnu.org/licenses/>. */
> +
> +#include <nss_module.h>
> +#include <nss_files.h>
> +
> +void
> +__nss_files_functions (nss_module_functions_untyped pointers)
> +{
> + void **fptr = pointers;
> +
> + /* Functions which are not implemented. */
> +#define _nss_files_getcanonname_r NULL
> +#define _nss_files_gethostbyaddr2_r NULL
> +#define _nss_files_getpublickey NULL
> +#define _nss_files_getsecretkey NULL
> +#define _nss_files_netname2user NULL
> +
> +#undef DEFINE_NSS_FUNCTION
> +#define DEFINE_NSS_FUNCTION(x) *fptr++ = _nss_files_##x;
> +#include "function.def"
> +
> +#ifdef PTR_MANGLE
> + void **end = fptr;
> + for (fptr = pointers; fptr != end; ++fptr)
> + PTR_MANGLE (*fptr);
> +#endif
> +}
Ok.
> diff --git a/nss/nss_module.c b/nss/nss_module.c
> index 60c070c851..7b42c585a4 100644
> --- a/nss/nss_module.c
> +++ b/nss/nss_module.c
> @@ -30,6 +30,7 @@
> #include <stdio.h>
> #include <stdlib.h>
> #include <string.h>
> +#include <nss_files.h>
>
> /* Suffix after .so of NSS service modules. This is a bit of magic,
> but we assume LIBNSS_FILES_SO looks like "libnss_files.so.2" and we
> @@ -110,10 +111,45 @@ static const function_name nss_function_name_array[] =
> #include "function.def"
> };
>
> +static bool
> +module_load_nss_files (struct nss_module *module)
> +{
> + if (is_nscd)
> + {
> + void (*cb) (size_t, struct traced_file *) = nscd_init_cb;
> +# ifdef PTR_DEMANGLE
> + PTR_DEMANGLE (cb);
> +# endif
> + _nss_files_init (cb);
> + }
> +
> + /* Initialize the function pointers, following the double-checked
> + locking idiom. */
> + __libc_lock_lock (nss_module_list_lock);
> + switch ((enum nss_module_state) atomic_load_acquire (&module->state))
> + {
> + case nss_module_uninitialized:
> + case nss_module_failed:
> + __nss_files_functions (module->functions.untyped);
> + module->handle = NULL;
> + /* Synchronizes with unlocked __nss_module_load atomic_load_acquire. */
> + atomic_store_release (&module->state, nss_module_loaded);
> + break;
> + case nss_module_loaded:
> + /* Nothing to clean up. */
> + break;
> + }
> + __libc_lock_unlock (nss_module_list_lock);
> + return true;
> +}
> +
Ok (it is mainly the code already presented on module_load()).
> /* Internal implementation of __nss_module_load. */
> static bool
> module_load (struct nss_module *module)
> {
> + if (strcmp (module->name, "files") == 0)
> + return module_load_nss_files (module);
> +
> void *handle;
> {
> char *shlib_name;
> @@ -360,7 +396,7 @@ __nss_module_freeres (void)
> struct nss_module *current = nss_module_list;
> while (current != NULL)
> {
> - if (current->state == nss_module_loaded)
> + if (current->state == nss_module_loaded && current->handle != NULL)
> __libc_dlclose (current->handle);
>
> struct nss_module *next = current->next;
Ok.
> diff --git a/nss/nss_module.h b/nss/nss_module.h
> index 05c4791d11..c1a1d90b60 100644
> --- a/nss/nss_module.h
> +++ b/nss/nss_module.h
> @@ -38,6 +38,10 @@ struct nss_module_functions
> typedef void *nss_module_functions_untyped[sizeof (struct nss_module_functions)
> / sizeof (void *)];
>
> +/* Locate the nss_files functions, as if by dlopen/dlsym. */
> +void __nss_files_functions (nss_module_functions_untyped pointers)
> + attribute_hidden;
> +
> /* Initialization state of a NSS module. */
> enum nss_module_state
> {
>
Ok.
next prev parent reply other threads:[~2021-07-07 13:49 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-29 10:11 [PATCH v2 0/7] nss_files move Florian Weimer
2021-06-29 10:11 ` [PATCH 1/7] inet: Add hidden prototype for __inet_network Florian Weimer
2021-07-07 13:33 ` Adhemerval Zanella
2021-06-29 10:11 ` [PATCH 2/7] libio: Add hidden prototype for ungetc Florian Weimer
2021-07-07 13:33 ` Adhemerval Zanella
2021-06-29 10:11 ` [PATCH v2 3/7] libio: Replace internal _IO_getdelim symbol with __getdelim Florian Weimer
2021-07-07 13:33 ` Adhemerval Zanella
2021-06-29 10:11 ` [PATCH 4/7] nss_files: Allocate nscd file registration data on the heap Florian Weimer
2021-07-07 13:35 ` Adhemerval Zanella
2021-06-29 10:11 ` [PATCH 5/7] nss_files: Add generic code for set*ent, end*ent and file open Florian Weimer
2021-07-07 13:42 ` Adhemerval Zanella
2021-06-29 10:11 ` [PATCH 6/7] nss_files: Move into libc Florian Weimer
2021-07-07 13:45 ` Adhemerval Zanella
2021-06-29 10:11 ` [PATCH 7/7] nss: Access nss_files through direct references Florian Weimer
2021-07-07 13:49 ` Adhemerval Zanella [this message]
2021-07-08 10:28 ` [PATCH v2 0/7] nss_files move Andreas Schwab
2021-07-08 10:33 ` Florian Weimer
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