From patchwork Wed Feb 3 18:34:12 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Adhemerval Zanella Netto X-Patchwork-Id: 41930 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 E9CFD39AF1BB; Wed, 3 Feb 2021 18:34:25 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org E9CFD39AF1BB DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1612377266; bh=qYzGSqqDDRTcWTqGG2cXFjBP/hyAv4fRvdXyiEBFuN4=; h=To:Subject:Date:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:List-Subscribe:From:Reply-To:Cc:From; b=V4zbXUvxSMciLrqyJGt5e0uIfWeFFgtDt3hBhAFnIsKsIOpEnp7qO+Z4e2udpy0bj Jx26oLPDje9O+hhj9GxB5YH+ZTMXCFKrXwhDlWSccsX/nlBvTgerC+5RNXpoVEtiwh 7tj7T0iFvERlFDxYi/FZggciYOB1Ez8Bn+6kWCJ8= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from mail-qv1-xf2b.google.com (mail-qv1-xf2b.google.com [IPv6:2607:f8b0:4864:20::f2b]) by sourceware.org (Postfix) with ESMTPS id 1ED6C386F033 for ; Wed, 3 Feb 2021 18:34:21 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 1ED6C386F033 Received: by mail-qv1-xf2b.google.com with SMTP id u16so443866qvo.9 for ; Wed, 03 Feb 2021 10:34:21 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=qYzGSqqDDRTcWTqGG2cXFjBP/hyAv4fRvdXyiEBFuN4=; b=LydPHNnDELnpgOYIhV5zbLtKNdOFdngQp/AsKD4YyGJ4pt4/jHGEOl2pFQJp/K0Llt 20uX5Q1PtIkjwghZICBPptKq7MIC2MwtpgQWDXdnhOjZPE9p61cY5gI1yf4JI3Vrop6F g+sw7S7+TIu272vIUl/vZ5lTF6v3pJMpE4DeZlhIQsdrKkl9WaChtDGy0tVKcu/fkuCG +2V8UKu/hlTqe8hrAmPLqFfDoM4P2zP6PfekUuuzn73ewu10HRshK9HTQcuM6R0G37l2 3tZDrsky+1gpcdNhk8pgCCXd081Wo6R0CRGhpvi8dDgTNDSsPnBE6SLg9v4c9BJq5PVv O2pA== X-Gm-Message-State: AOAM532XEmh+pT4/S+hesgpxqLxBogyLKdle1xIp2hd5K6fKav2Xnoy+ 42DicWNZx1+NzYOLVQoL+fuqP9qthcFZJQ== X-Google-Smtp-Source: ABdhPJzwEEqlSFi8nG/OafsdPTmaXbxvlyH11ui6Q99gweeO0IT0E6pF9+uW/JTo0U9j/S1CDIUCnQ== X-Received: by 2002:a05:6214:b33:: with SMTP id w19mr3969440qvj.35.1612377259560; Wed, 03 Feb 2021 10:34:19 -0800 (PST) Received: from localhost.localdomain ([177.194.48.209]) by smtp.googlemail.com with ESMTPSA id h63sm2051419qtd.14.2021.02.03.10.34.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 03 Feb 2021 10:34:18 -0800 (PST) To: libc-alpha@sourceware.org Subject: [PATCH 1/3] linux: Require /dev/shm as the shared memory file system [BZ #25383] Date: Wed, 3 Feb 2021 15:34:12 -0300 Message-Id: <20210203183414.571813-1-adhemerval.zanella@linaro.org> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-Spam-Status: No, score=-13.5 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, KAM_SHORT, RCVD_IN_DNSWL_NONE, 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: Adhemerval Zanella via Libc-alpha From: Adhemerval Zanella Netto Reply-To: Adhemerval Zanella Cc: Florian Weimer Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" From: Florian Weimer This is an updated version with the patch included in the bug report, I rebased against master and add the following changes: - The shm-directory.h is moved to include instead of posix, since it is used on different subdirs. - The shm-directory build rule is added on posix/Makefile instead of sysdeps/posix/Makefile - There is no need for a libc_hidden_def (__shm_get_name). --- Previously, glibc would pick an arbitrary tmpfs file system from /proc/mounts if /dev/shm was not available. This could lead to an unsuitable file system being picked for the backing storage for shm_open, sem_open, and related functions. This patch introduces a new function, __shm_get_name, which builds the file name under the appropriate (now hard-coded) directory. It is called from the various shm_* and sem_* function. Unlike the SHM_GET_NAME macro it replaces, the callers handle the return values and errno updates. shm-directory.c is moved directly into the posix subdirectory because it can be implemented directly using POSIX functionality. It resides in libc because it is needed by both librt and nptl/htl. In the sem_open implementation, tmpfname is initialized directly from a string constant. This happens to remove one alloca call. Checked on x86_64-linux-gnu. --- NEWS | 5 +- htl/Makefile | 2 - htl/Versions | 1 - {sysdeps/nptl => include}/shm-directory.h | 30 +++-- nptl/Makefile | 1 - nptl/Versions | 1 - nptl/nptlfreeres.c | 1 - nptl/pthreadP.h | 1 - posix/Makefile | 3 +- posix/Versions | 1 + {sysdeps/posix => posix}/shm-directory.c | 30 +++-- sysdeps/htl/shm-directory.h | 30 ----- sysdeps/posix/Makefile | 6 - sysdeps/posix/shm-directory.h | 66 ---------- sysdeps/posix/shm_open.c | 10 +- sysdeps/posix/shm_unlink.c | 13 +- sysdeps/pthread/sem_open.c | 34 ++--- sysdeps/pthread/sem_unlink.c | 10 +- sysdeps/unix/sysv/linux/shm-directory.c | 147 ---------------------- 19 files changed, 89 insertions(+), 303 deletions(-) rename {sysdeps/nptl => include}/shm-directory.h (56%) rename {sysdeps/posix => posix}/shm-directory.c (60%) delete mode 100644 sysdeps/htl/shm-directory.h delete mode 100644 sysdeps/posix/shm-directory.h delete mode 100644 sysdeps/unix/sysv/linux/shm-directory.c diff --git a/NEWS b/NEWS index 1ca12bc1a2..85e84fe536 100644 --- a/NEWS +++ b/NEWS @@ -20,7 +20,10 @@ Deprecated and removed features, and other changes affecting compatibility: Changes to build and runtime requirements: - [Add changes to build and runtime requirements here] +* On Linux, the shm_open, sem_open, and related functions now expect the + file shared memory file system to be mounted at /dev/shm. These functions + no longer search among the system's mount points for a suitable + replacement if /dev/shm is not available. Security related changes: diff --git a/htl/Makefile b/htl/Makefile index 38d9f8c590..9adc95e07f 100644 --- a/htl/Makefile +++ b/htl/Makefile @@ -132,8 +132,6 @@ libpthread-routines := pt-attr pt-attr-destroy pt-attr-getdetachstate \ sem-post sem-timedwait sem-trywait sem_unlink \ sem-wait sem-waitfast \ \ - shm-directory \ - \ cancellation \ cthreads-compat \ herrno \ diff --git a/htl/Versions b/htl/Versions index 95496297e3..9506043c62 100644 --- a/htl/Versions +++ b/htl/Versions @@ -168,7 +168,6 @@ libpthread { GLIBC_PRIVATE { __pthread_initialize_minimal; - __shm_directory; __pthread_threads; __cthread_detach; diff --git a/sysdeps/nptl/shm-directory.h b/include/shm-directory.h similarity index 56% rename from sysdeps/nptl/shm-directory.h rename to include/shm-directory.h index 995f59834d..1d3ffb6137 100644 --- a/sysdeps/nptl/shm-directory.h +++ b/include/shm-directory.h @@ -1,4 +1,4 @@ -/* Header for directory for shm/sem files. NPTL version. +/* Header for directory for shm/sem files. Copyright (C) 2014-2021 Free Software Foundation, Inc. This file is part of the GNU C Library. @@ -18,14 +18,24 @@ #ifndef _SHM_DIRECTORY_H -#include - -/* For NPTL the __shm_directory function lives in libpthread. - We don't want PLT calls from there. But it's also used from - librt, so it cannot just be declared hidden. */ - -#if IS_IN (libpthread) -hidden_proto (__shm_directory) -#endif +#include +#include +#include + +/* The directory that contains shared POSIX objects. */ +#define SHMDIR _PATH_DEV "shm/" + +struct shmdir_name +{ + /* The combined prefix/name. The sizeof includes the terminating + NUL byte. 4 bytes are needed for the optional "sem." prefix. */ + char name[sizeof (SHMDIR) + 4 + NAME_MAX]; +}; + +/* Sets RESULT->name to the constructed name and returns 0 on success, + or -1 on failure. Includes the "sem." prefix in the name if + SEM_PREFIX is true. */ +int __shm_get_name (struct shmdir_name *result, const char *name, + bool sem_prefix); #endif /* shm-directory.h */ diff --git a/nptl/Makefile b/nptl/Makefile index 0282e07390..c49134b936 100644 --- a/nptl/Makefile +++ b/nptl/Makefile @@ -137,7 +137,6 @@ libpthread-routines = nptl-init nptlfreeres vars events version pt-interp \ pthread_once \ old_pthread_atfork \ pthread_getcpuclockid \ - shm-directory \ sem_init sem_destroy \ sem_open sem_close sem_unlink \ sem_getvalue \ diff --git a/nptl/Versions b/nptl/Versions index 02650fe91c..5db713d1ae 100644 --- a/nptl/Versions +++ b/nptl/Versions @@ -303,7 +303,6 @@ libpthread { __pthread_unwind; __pthread_get_minstack; __pthread_barrier_init; __pthread_barrier_wait; __futex_abstimed_wait64; __futex_abstimed_wait_cancelable64; - __shm_directory; __libpthread_freeres; } } diff --git a/nptl/nptlfreeres.c b/nptl/nptlfreeres.c index 77ad5b53ff..d295bcb3c3 100644 --- a/nptl/nptlfreeres.c +++ b/nptl/nptlfreeres.c @@ -27,6 +27,5 @@ __libpthread_freeres (void) { call_function_static_weak (__default_pthread_attr_freeres); call_function_static_weak (__nptl_stacks_freeres); - call_function_static_weak (__shm_directory_freeres); call_function_static_weak (__nptl_unwind_freeres); } diff --git a/nptl/pthreadP.h b/nptl/pthreadP.h index e5efa2e62d..d078128230 100644 --- a/nptl/pthreadP.h +++ b/nptl/pthreadP.h @@ -629,7 +629,6 @@ extern void __nptl_set_robust (struct pthread *self); #endif extern void __nptl_stacks_freeres (void) attribute_hidden; -extern void __shm_directory_freeres (void) attribute_hidden; extern void __wait_lookup_done (void) attribute_hidden; diff --git a/posix/Makefile b/posix/Makefile index 956ef7d397..f54015b9a8 100644 --- a/posix/Makefile +++ b/posix/Makefile @@ -65,7 +65,8 @@ routines := \ spawnattr_setsigmask spawnattr_setschedpolicy spawnattr_setschedparam \ posix_madvise \ get_child_max sched_cpucount sched_cpualloc sched_cpufree \ - streams-compat + streams-compat \ + shm-directory aux := init-posix environ tests := test-errno tstgetopt testfnm runtests runptests \ diff --git a/posix/Versions b/posix/Versions index 7d06a6d0c0..cfd3819966 100644 --- a/posix/Versions +++ b/posix/Versions @@ -150,5 +150,6 @@ libc { GLIBC_PRIVATE { __libc_fork; __libc_pread; __libc_pwrite; __nanosleep_nocancel; __pause_nocancel; + __shm_get_name; } } diff --git a/sysdeps/posix/shm-directory.c b/posix/shm-directory.c similarity index 60% rename from sysdeps/posix/shm-directory.c rename to posix/shm-directory.c index a0510c1ff5..c06bf96aa7 100644 --- a/sysdeps/posix/shm-directory.c +++ b/posix/shm-directory.c @@ -16,23 +16,31 @@ License along with the GNU C Library; if not, see . */ -#include #include #if _POSIX_MAPPED_FILES -# include - -# define SHMDIR (_PATH_DEV "shm/") +#include +#include +#include -const char * -__shm_directory (size_t *len) +int +__shm_get_name (struct shmdir_name *result, const char *name, bool sem_prefix) { - *len = sizeof SHMDIR - 1; - return SHMDIR; + while (name[0] == '/') + ++name; + size_t namelen = strlen (name); + + struct alloc_buffer buffer + = alloc_buffer_create (result->name, sizeof (result->name)); + alloc_buffer_copy_bytes (&buffer, SHMDIR, strlen (SHMDIR)); + if (sem_prefix) + alloc_buffer_copy_bytes (&buffer, "sem.", strlen ("sem.")); + alloc_buffer_copy_bytes (&buffer, name, namelen + 1); + if (namelen == 0 || memchr (name, '/', namelen) != NULL + || alloc_buffer_has_failed (&buffer)) + return -1; + return 0; } -# if IS_IN (libpthread) -hidden_def (__shm_directory) -# endif #endif diff --git a/sysdeps/htl/shm-directory.h b/sysdeps/htl/shm-directory.h deleted file mode 100644 index 8bfd7287b5..0000000000 --- a/sysdeps/htl/shm-directory.h +++ /dev/null @@ -1,30 +0,0 @@ -/* Header for directory for shm/sem files. libpthread version. - Copyright (C) 2014-2021 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 - . */ - -#ifndef _SHM_DIRECTORY_H - -#include - -/* For libpthread the __shm_directory function lives in libpthread. - We don't want PLT calls from there. But it's also used from - librt, so it cannot just be declared hidden. */ - -#if IS_IN (libpthread) -hidden_proto (__shm_directory) -#endif -#endif /* shm-directory.h */ diff --git a/sysdeps/posix/Makefile b/sysdeps/posix/Makefile index 52f20f5d97..b58aa6aadb 100644 --- a/sysdeps/posix/Makefile +++ b/sysdeps/posix/Makefile @@ -3,9 +3,3 @@ L_tmpnam = 20 TMP_MAX = 238328 L_ctermid = 9 L_cuserid = 9 - -ifeq ($(subdir)|$(have-thread-library),rt|no) -# With NPTL, this lives in libpthread so it can be used for sem_open too. -# Without NPTL, it's just private in librt. -librt-routines += shm-directory -endif diff --git a/sysdeps/posix/shm-directory.h b/sysdeps/posix/shm-directory.h deleted file mode 100644 index 7254bdabba..0000000000 --- a/sysdeps/posix/shm-directory.h +++ /dev/null @@ -1,66 +0,0 @@ -/* Header for directory for shm/sem files. - Copyright (C) 2014-2021 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 - . */ - -#ifndef _SHM_DIRECTORY_H - -#include -#include -#include -#include -#include - -extern const char *__shm_directory (size_t *len); - -/* This defines local variables SHM_DIR and SHM_DIRLEN, giving the - directory prefix (with trailing slash) and length (not including '\0' - terminator) of the directory used for shm files. If that cannot be - determined, it sets errno to ENOSYS and returns RETVAL_FOR_INVALID. - - This uses the local variable NAME as an lvalue, and increments it past - any leading slashes. It then defines the local variable NAMELEN, giving - strlen (NAME) + 1. If NAME is invalid, it sets errno to - ERRNO_FOR_INVALID and returns RETVAL_FOR_INVALID. Finally, it defines - the local variable SHM_NAME, giving the absolute file name of the shm - file corresponding to NAME. PREFIX is a string constant used as a - prefix on NAME. */ - -#define SHM_GET_NAME(errno_for_invalid, retval_for_invalid, prefix) \ - size_t shm_dirlen; \ - const char *shm_dir = __shm_directory (&shm_dirlen); \ - /* If we don't know what directory to use, there is nothing we can do. */ \ - if (__glibc_unlikely (shm_dir == NULL)) \ - { \ - __set_errno (ENOSYS); \ - return retval_for_invalid; \ - } \ - /* Construct the filename. */ \ - while (name[0] == '/') \ - ++name; \ - size_t namelen = strlen (name) + 1; \ - /* Validate the filename. */ \ - if (namelen == 1 || namelen >= NAME_MAX || strchr (name, '/') != NULL) \ - { \ - __set_errno (errno_for_invalid); \ - return retval_for_invalid; \ - } \ - char *shm_name = __alloca (shm_dirlen + sizeof prefix - 1 + namelen); \ - __mempcpy (__mempcpy (__mempcpy (shm_name, shm_dir, shm_dirlen), \ - prefix, sizeof prefix - 1), \ - name, namelen) - -#endif /* shm-directory.h */ diff --git a/sysdeps/posix/shm_open.c b/sysdeps/posix/shm_open.c index aabc724b27..1817c52f7f 100644 --- a/sysdeps/posix/shm_open.c +++ b/sysdeps/posix/shm_open.c @@ -24,6 +24,7 @@ #else +# include # include # include # include @@ -33,7 +34,12 @@ int shm_open (const char *name, int oflag, mode_t mode) { - SHM_GET_NAME (EINVAL, -1, ""); + struct shmdir_name dirname; + if (__shm_get_name (&dirname, name, false) != 0) + { + __set_errno (EINVAL); + return -1; + } oflag |= O_NOFOLLOW | O_CLOEXEC; @@ -41,7 +47,7 @@ shm_open (const char *name, int oflag, mode_t mode) int state; pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &state); - int fd = open (shm_name, oflag, mode); + int fd = open (dirname.name, oflag, mode); if (fd == -1 && __glibc_unlikely (errno == EISDIR)) /* It might be better to fold this error with EINVAL since directory names are just another example for unsuitable shared diff --git a/sysdeps/posix/shm_unlink.c b/sysdeps/posix/shm_unlink.c index f3258a0f5a..c90b854c78 100644 --- a/sysdeps/posix/shm_unlink.c +++ b/sysdeps/posix/shm_unlink.c @@ -25,16 +25,21 @@ #include #include -#include "shm-directory.h" +#include /* Remove shared memory object. */ int shm_unlink (const char *name) { - SHM_GET_NAME (ENOENT, -1, ""); - - int result = unlink (shm_name); + struct shmdir_name dirname; + if (__shm_get_name (&dirname, name, false) != 0) + { + __set_errno (ENOENT); + return -1; + } + + int result = unlink (dirname.name); if (result < 0 && errno == EPERM) __set_errno (EACCES); return result; diff --git a/sysdeps/pthread/sem_open.c b/sysdeps/pthread/sem_open.c index b0b722121d..d666414f32 100644 --- a/sysdeps/pthread/sem_open.c +++ b/sysdeps/pthread/sem_open.c @@ -62,8 +62,9 @@ int __sem_mappings_lock attribute_hidden = LLL_LOCK_INITIALIZER; /* Search for existing mapping and if possible add the one provided. */ static sem_t * -check_add_mapping (const char *name, size_t namelen, int fd, sem_t *existing) +check_add_mapping (const char *name, int fd, sem_t *existing) { + size_t namelen = strlen (name); sem_t *result = SEM_FAILED; /* Get the information about the file. */ @@ -150,8 +151,12 @@ sem_open (const char *name, int oflag, ...) return SEM_FAILED; } - /* Create the name of the final file in local variable SHM_NAME. */ - SHM_GET_NAME (EINVAL, SEM_FAILED, SEM_SHM_PREFIX); + struct shmdir_name dirname; + if (__shm_get_name (&dirname, name, true) != 0) + { + __set_errno (EINVAL); + return SEM_FAILED; + } /* Disable asynchronous cancellation. */ #ifdef __libc_ptf_call @@ -164,7 +169,7 @@ sem_open (const char *name, int oflag, ...) if ((oflag & O_CREAT) == 0 || (oflag & O_EXCL) == 0) { try_again: - fd = __libc_open (shm_name, + fd = __libc_open (dirname.name, (oflag & ~(O_CREAT|O_ACCMODE)) | O_NOFOLLOW | O_RDWR); if (fd == -1) @@ -178,13 +183,12 @@ sem_open (const char *name, int oflag, ...) else /* Check whether we already have this semaphore mapped and create one if necessary. */ - result = check_add_mapping (name, namelen, fd, SEM_FAILED); + result = check_add_mapping (name, fd, SEM_FAILED); } else { /* We have to open a temporary file first since it must have the correct form before we can start using it. */ - char *tmpfname; mode_t mode; unsigned int value; va_list ap; @@ -217,16 +221,11 @@ sem_open (const char *name, int oflag, ...) memset ((char *) &sem.initsem + sizeof (struct new_sem), '\0', sizeof (sem_t) - sizeof (struct new_sem)); - tmpfname = __alloca (shm_dirlen + sizeof SEM_SHM_PREFIX + 6); - char *xxxxxx = __mempcpy (tmpfname, shm_dir, shm_dirlen); - + char tmpfname[] = SHMDIR "sem.XXXXXX"; int retries = 0; #define NRETRIES 50 while (1) { - /* Add the suffix for mktemp. */ - strcpy (xxxxxx, "XXXXXX"); - /* We really want to use mktemp here. We cannot use mkstemp since the file must be opened with a specific mode. The mode cannot later be set since then we cannot apply the @@ -244,7 +243,12 @@ sem_open (const char *name, int oflag, ...) if (errno == EEXIST) { if (++retries < NRETRIES) - continue; + { + /* Restore the six placeholder bytes before the + null terminator before the next attempt. */ + memcpy (tmpfname + sizeof (tmpfname) - 7, "XXXXXX", 6); + continue; + } __set_errno (EAGAIN); } @@ -265,7 +269,7 @@ sem_open (const char *name, int oflag, ...) fd, 0)) != MAP_FAILED) { /* Create the file. Don't overwrite an existing file. */ - if (link (tmpfname, shm_name) != 0) + if (link (tmpfname, dirname.name) != 0) { /* Undo the mapping. */ (void) munmap (result, sizeof (sem_t)); @@ -290,7 +294,7 @@ sem_open (const char *name, int oflag, ...) /* Insert the mapping into the search tree. This also determines whether another thread sneaked by and already added such a mapping despite the fact that we created it. */ - result = check_add_mapping (name, namelen, fd, result); + result = check_add_mapping (name, fd, result); } /* Now remove the temporary name. This should never fail. If diff --git a/sysdeps/pthread/sem_unlink.c b/sysdeps/pthread/sem_unlink.c index faafbe4e91..1f06a55b8e 100644 --- a/sysdeps/pthread/sem_unlink.c +++ b/sysdeps/pthread/sem_unlink.c @@ -27,11 +27,15 @@ int sem_unlink (const char *name) { - /* Construct the filename. */ - SHM_GET_NAME (ENOENT, -1, SEM_SHM_PREFIX); + struct shmdir_name dirname; + if (__shm_get_name (&dirname, name, true) != 0) + { + __set_errno (ENOENT); + return -1; + } /* Now try removing it. */ - int ret = unlink (shm_name); + int ret = unlink (dirname.name); if (ret < 0 && errno == EPERM) __set_errno (EACCES); return ret; diff --git a/sysdeps/unix/sysv/linux/shm-directory.c b/sysdeps/unix/sysv/linux/shm-directory.c deleted file mode 100644 index ea6d2a46c1..0000000000 --- a/sysdeps/unix/sysv/linux/shm-directory.c +++ /dev/null @@ -1,147 +0,0 @@ -/* Determine directory for shm/sem files. Linux version. - Copyright (C) 2000-2021 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 "shm-directory.h" - -#include -#include -#include -#include -#include -#include -#include -#include "linux_fsinfo.h" - - -/* Mount point of the shared memory filesystem. */ -static struct -{ - char *dir; - size_t dirlen; -} mountpoint; - -/* This is the default directory. */ -static const char defaultdir[] = "/dev/shm/"; - -/* Protect the `mountpoint' variable above. */ -__libc_once_define (static, once); - - -/* Determine where the shmfs is mounted (if at all). */ -static void -where_is_shmfs (void) -{ - char buf[512]; - struct statfs f; - struct mntent resmem; - struct mntent *mp; - FILE *fp; - - /* The canonical place is /dev/shm. This is at least what the - documentation tells everybody to do. */ - if (__statfs (defaultdir, &f) == 0 && (f.f_type == SHMFS_SUPER_MAGIC - || f.f_type == RAMFS_MAGIC)) - { - /* It is in the normal place. */ - mountpoint.dir = (char *) defaultdir; - mountpoint.dirlen = sizeof (defaultdir) - 1; - - return; - } - - /* OK, do it the hard way. Look through the /proc/mounts file and if - this does not exist through /etc/fstab to find the mount point. */ - fp = __setmntent ("/proc/mounts", "r"); - if (__glibc_unlikely (fp == NULL)) - { - fp = __setmntent (_PATH_MNTTAB, "r"); - if (__glibc_unlikely (fp == NULL)) - /* There is nothing we can do. Blind guesses are not helpful. */ - return; - } - - /* Now read the entries. */ - while ((mp = __getmntent_r (fp, &resmem, buf, sizeof buf)) != NULL) - /* The original name is "shm" but this got changed in early Linux - 2.4.x to "tmpfs". */ - if (strcmp (mp->mnt_type, "tmpfs") == 0 - || strcmp (mp->mnt_type, "shm") == 0) - { - /* Found it. There might be more than one place where the - filesystem is mounted but one is enough for us. */ - size_t namelen; - - /* First make sure this really is the correct entry. At least - some versions of the kernel give wrong information because - of the implicit mount of the shmfs for SysV IPC. */ - if (__statfs (mp->mnt_dir, &f) != 0 || (f.f_type != SHMFS_SUPER_MAGIC - && f.f_type != RAMFS_MAGIC)) - continue; - - namelen = strlen (mp->mnt_dir); - - if (namelen == 0) - /* Hum, maybe some crippled entry. Keep on searching. */ - continue; - - mountpoint.dir = (char *) malloc (namelen + 2); - if (mountpoint.dir != NULL) - { - char *cp = __mempcpy (mountpoint.dir, mp->mnt_dir, namelen); - if (cp[-1] != '/') - *cp++ = '/'; - *cp = '\0'; - mountpoint.dirlen = cp - mountpoint.dir; - } - - break; - } - - /* Close the stream. */ - __endmntent (fp); -} - - -const char * -__shm_directory (size_t *len) -{ - /* Determine where the shmfs is mounted. */ - __libc_once (once, where_is_shmfs); - - /* If we don't know the mount points there is nothing we can do. Ever. */ - if (__glibc_unlikely (mountpoint.dir == NULL)) - { - __set_errno (ENOSYS); - return NULL; - } - - *len = mountpoint.dirlen; - return mountpoint.dir; -} -#if IS_IN (libpthread) -hidden_def (__shm_directory) - -/* Make sure the table is freed if we want to free everything before - exiting. */ -void -__shm_directory_freeres (void) -{ - if (mountpoint.dir != defaultdir) - free (mountpoint.dir); -} -#endif