From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-3.9 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_EF,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL,SPF_HELO_PASS,SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from sourceware.org (server1.sourceware.org [209.132.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dcvr.yhbt.net (Postfix) with ESMTPS id 122E91F45E for ; Fri, 14 Feb 2020 19:08:19 +0000 (UTC) DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:to:references:from:subject:message-id:date :mime-version:in-reply-to:content-type :content-transfer-encoding; q=dns; s=default; b=aZHp8BN3bW4AXVMr ESabBo34ve+M+k2kD6Y0iCSEv2BgMTYZtoTcslGGNfhSY1xuuUkraY6nMIcfxY+s X/HRbyQNK0QPRS8HEGRN53Cp6H2ro4smhMyc9EQFySQuJQK5nR0xSX3CuTc8YHoO QpfhW6UFcaUxVjbua5cA7ZEhQ8k= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:to:references:from:subject:message-id:date :mime-version:in-reply-to:content-type :content-transfer-encoding; s=default; bh=iibXjokD7Sup0Vvnxu4y5P wllhc=; b=sOBop/oJVHaNHOMoadcSG65gUpCMRcKVMsDYzWSpq2kG2JmhFhuz3l VtOTLBlrpyU/+WsHwAUf0cDTYn5JCuAtzU+bE9sBVNpH9i09p0OQgHJnt3dOF4E6 /HGIPot7JOlXevZhFZuDQQqlvWjVodYA0a+WGXVNSauMue636gUqA= Received: (qmail 30634 invoked by alias); 14 Feb 2020 19:08:16 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Received: (qmail 30626 invoked by uid 89); 14 Feb 2020 19:08:16 -0000 Authentication-Results: sourceware.org; auth=none X-HELO: mail-qv1-f67.google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=to:references:from:autocrypt:subject:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=e3e+1Etnu6oV+jetIswogfgINIsAUb3OYbRy1/PjB2s=; b=foQZvSNbseXxIgdD+C9t/XuetJvDSxfLKbBE0z7Jx+KVUYheVoA7+vCAOffc3IMGnf VrprqeIeRZDTCw72NJOqRBQWAMiD9X/xiIy4bGHVhlTVxNN+IdcqxnuZ8yj8oyRDXGV2 XrN57o5VQYwHTaM12wsDrtgbMQ95n2cDkE1rlB+BwCLYsua6qJZKWabqk9HJyDRO62YZ 9vMp7usgeycGFYK8Tfgx5VLTzU7PLETVi9YmCFuCPDPShM57yocpCHB2iIxtegd8obXK XDsXeF3LVlbzgmWZMU2L1enypJHzCrOVfko9sFZKTjYVyMq9rOhY93xsAJtEDoKXWPYQ TBgw== To: libc-alpha@sourceware.org References: From: Adhemerval Zanella Subject: Re: [PATCH 1/3] : Add type safety and port to Hurd Message-ID: <1cdfa358-5bc0-56b7-89d2-0f7cfd4d4fc0@linaro.org> Date: Fri, 14 Feb 2020 16:08:05 -0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit On 14/02/2020 15:11, Florian Weimer wrote: > The new type struct fd_to_filename makes the allocation of the > backing storage explicit. > > Hurd uses /dev/fd, not /proc/self/fd. > --- > libio/freopen.c | 4 +- > libio/freopen64.c | 4 +- > misc/Makefile | 6 +- > misc/fd_to_filename.c | 104 +++++++++++++++++ > misc/tst-fd_to_filename.c | 105 ++++++++++++++++++ > sysdeps/generic/arch-fd_to_filename.h | 19 ++++ > sysdeps/generic/fd_to_filename.h | 25 +++-- > sysdeps/mach/hurd/arch-fd_to_filename.h | 19 ++++ > ...fd_to_filename.h => arch-fd_to_filename.h} | 22 +--- > 9 files changed, 275 insertions(+), 33 deletions(-) > create mode 100644 misc/fd_to_filename.c > create mode 100644 misc/tst-fd_to_filename.c > create mode 100644 sysdeps/generic/arch-fd_to_filename.h > create mode 100644 sysdeps/mach/hurd/arch-fd_to_filename.h > rename sysdeps/unix/sysv/linux/{fd_to_filename.h => arch-fd_to_filename.h} (58%) > > diff --git a/libio/freopen.c b/libio/freopen.c > index bab3ba204a..884cdb2961 100644 > --- a/libio/freopen.c > +++ b/libio/freopen.c > @@ -37,7 +37,7 @@ FILE * > freopen (const char *filename, const char *mode, FILE *fp) > { > FILE *result = NULL; > - char fdfilename[FD_TO_FILENAME_SIZE]; > + struct fd_to_filename fdfilename; > > CHECK_FILE (fp, NULL); > > @@ -50,7 +50,7 @@ freopen (const char *filename, const char *mode, FILE *fp) > > int fd = _IO_fileno (fp); > const char *gfilename > - = filename != NULL ? filename : fd_to_filename (fd, fdfilename); > + = filename != NULL ? filename : __fd_to_filename (fd, &fdfilename); > > fp->_flags2 |= _IO_FLAGS2_NOCLOSE; > #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1) > diff --git a/libio/freopen64.c b/libio/freopen64.c > index c0ce604e6e..0d2c5264c7 100644 > --- a/libio/freopen64.c > +++ b/libio/freopen64.c > @@ -36,7 +36,7 @@ FILE * > freopen64 (const char *filename, const char *mode, FILE *fp) > { > FILE *result = NULL; > - char fdfilename[FD_TO_FILENAME_SIZE]; > + struct fd_to_filename fdfilename; > > CHECK_FILE (fp, NULL); > > @@ -49,7 +49,7 @@ freopen64 (const char *filename, const char *mode, FILE *fp) > > int fd = _IO_fileno (fp); > const char *gfilename > - = filename != NULL ? filename : fd_to_filename (fd, fdfilename); > + = filename != NULL ? filename : __fd_to_filename (fd, &fdfilename); > > fp->_flags2 |= _IO_FLAGS2_NOCLOSE; > _IO_file_close_it (fp); > diff --git a/misc/Makefile b/misc/Makefile > index e0465980c7..b8fed5783d 100644 > --- a/misc/Makefile > +++ b/misc/Makefile > @@ -72,7 +72,7 @@ routines := brk sbrk sstk ioctl \ > fgetxattr flistxattr fremovexattr fsetxattr getxattr \ > listxattr lgetxattr llistxattr lremovexattr lsetxattr \ > removexattr setxattr getauxval ifunc-impl-list makedev \ > - allocate_once > + allocate_once fd_to_filename > > generated += tst-error1.mtrace tst-error1-mem.out \ > tst-allocate_once.mtrace tst-allocate_once-mem.out > @@ -97,6 +97,10 @@ endif > tests-internal := tst-atomic tst-atomic-long tst-allocate_once > tests-static := tst-empty > > +# Test for the internal, non-exported __fd_to_filename function. > +tests-internal += tst-fd_to_filename > +tests-static += tst-fd_to_filename > + > ifeq ($(run-built-tests),yes) > tests-special += $(objpfx)tst-error1-mem.out \ > $(objpfx)tst-allocate_once-mem.out > diff --git a/misc/fd_to_filename.c b/misc/fd_to_filename.c > new file mode 100644 > index 0000000000..911c22cf2b > --- /dev/null > +++ b/misc/fd_to_filename.c > @@ -0,0 +1,104 @@ > +/* Construct a pathname under /proc/self/fd (or /dev/fd for Hurd). > + Copyright (C) 2020 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 > + > +/* The split into groups of three digits is arbitrary, but it covers > + the common case of descriptors less than 1000 fairly > + efficiently. */ > + > +/* Writes two digits to P. VALUE must be between 0 and 99 > + (inclusive). Returns the address after the written digits. */ > +static char * > +digit2 (char *p, int value) > +{ > + p[0] = '0' + (value / 10); > + p[1] = '0' + (value % 10); > + return p + 2; > +} > + > +/* Writes three digits to P. VALUE must be between 0 and 999 > + (inclusive). Returns the address after the written digits. */ > +static char * > +digit3 (char *p, int value) > +{ > + p[0] = '0' + (value / 100); > + p[1] = '0' + ((value / 10) % 10); > + p[2] = '0' + (value % 10); > + return p + 3; > +} > + > +/* Writes one to three digits to P, depending on VALUE, which must be > + less than 1000. Returns the address after the written digits. */ > +static char * > +digit123 (char *p, int value) > +{ > + if (value < 10) > + { > + p[0] = '0' + value; > + return p + 1; > + } > + else if (value < 100) > + return digit2 (p, value); > + else > + return digit3 (p, value); > +} > + > +char * > +__fd_to_filename (int descriptor, struct fd_to_filename *storage) > +{ > + char *p = mempcpy (storage->buffer, FD_TO_FILENAME_PREFIX, > + strlen (FD_TO_FILENAME_PREFIX)); > + if (__glibc_likely (descriptor >= 0)) > + { > + if (descriptor < 1000) > + p = digit123 (p, descriptor); > + else if (descriptor < 1000 * 1000) > + { > + p = digit123 (p, descriptor / 1000); > + p = digit3 (p, descriptor % 1000); > + } > + else if (descriptor < 1000 * 1000 * 1000) > + { > + p = digit123 (p, descriptor / (1000 * 1000)); > + p = digit3 (p, (descriptor / 1000) % 1000); > + p = digit3 (p, descriptor % 1000); > + } > + else > + { > + if (descriptor < 2000 * 1000 * 1000) > + { > + *p = '1'; > + descriptor -= 1000 * 1000 * 1000; > + } > + else > + { > + *p = '2'; > + descriptor -= 2000 * 1000 * 1000; > + } > + ++p; > + p = digit3 (p, descriptor / (1000 * 1000)); > + p = digit3 (p, (descriptor / 1000) % 1000); > + p = digit3 (p, descriptor % 1000); > + } > + } > + > + *p = '\0'; > + return storage->buffer; > +} Do we really such optimization which results in somewhat complicate code? Couldn't we use something simple as: char * __fd_to_filename (int descriptor, struct fd_to_filename *storage) { char *buf = storage->buffer; int i, j; for (i = 0; (buf[i] = FD_TO_FILENAME_PREFIX[i]); i++); if (descriptor == 0) { buf[i] = '0'; buf[i+1] = '\0'; return storage->buffer; } for (j = descriptor; j != 0; j /= 10, i++); buf[i] = '\0'; for (; descriptor != 0; descriptor /= 10) buf[--i] = '0' + descriptor % 10; return storage->buffer; } > diff --git a/misc/tst-fd_to_filename.c b/misc/tst-fd_to_filename.c > new file mode 100644 > index 0000000000..480f613dcf > --- /dev/null > +++ b/misc/tst-fd_to_filename.c > @@ -0,0 +1,105 @@ > +/* Test for /proc/self/fd (or /dev/fd) pathname construction. > + Copyright (C) 2020 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 > + > +/* Run a check on one value. */ > +static void > +check (int value) > +{ > + struct fd_to_filename storage; > + char *actual = __fd_to_filename (value, &storage); > + char expected[100]; > + snprintf (expected, sizeof (expected), FD_TO_FILENAME_PREFIX "%d", value); > + > + if (value < 0) > + /* Negative inputs are invalid, but the output should still be > + deterministic. */ > + TEST_COMPARE_STRING (actual, FD_TO_FILENAME_PREFIX); > + else > + TEST_COMPARE_STRING (actual, expected); > +} > + > +/* Check various ranges constructed around powers. */ > +static void > +check_ranges (int base) > +{ > + unsigned int power = 1; > + do > + { > + for (int factor = 1; factor < base; ++factor) > + for (int shift = -1000; shift <= 1000; ++shift) > + { > + check (factor * power + shift); > + check (-(factor * power + shift)); > + } > + } > + while (!__builtin_mul_overflow (power, base, &power)); > +} > + > +/* Check that it is actually possible to use a the constructed > + name. */ > +static void > +check_open (void) > +{ > + int pipes[2]; > + xpipe (pipes); > + > + struct fd_to_filename storage; > + int read_alias = xopen (__fd_to_filename (pipes[0], &storage), O_RDONLY, 0); > + int write_alias = xopen (__fd_to_filename (pipes[1], &storage), O_WRONLY, 0); > + > + /* Ensure that all the descriptor numbers are different. */ > + TEST_VERIFY (pipes[0] < pipes[1]); > + TEST_VERIFY (pipes[1] < read_alias); > + TEST_VERIFY (read_alias < write_alias); > + > + xwrite (write_alias, "1", 1); > + char buf[16]; > + TEST_COMPARE_BLOB ("1", 1, buf, read (pipes[0], buf, sizeof (buf))); > + > + xwrite (pipes[1], "2", 1); > + TEST_COMPARE_BLOB ("2", 1, buf, read (read_alias, buf, sizeof (buf))); > + > + xwrite (write_alias, "3", 1); > + TEST_COMPARE_BLOB ("3", 1, buf, read (read_alias, buf, sizeof (buf))); > + > + xwrite (pipes[1], "4", 1); > + TEST_COMPARE_BLOB ("4", 1, buf, read (pipes[0], buf, sizeof (buf))); > + > + xclose (write_alias); > + xclose (read_alias); > + xclose (pipes[1]); > + xclose (pipes[0]); > +} > + > +static int > +do_test (void) > +{ > + check_ranges (2); > + check_ranges (10); > + > + check_open (); > + > + return 0; > +} > + > +#include > diff --git a/sysdeps/generic/arch-fd_to_filename.h b/sysdeps/generic/arch-fd_to_filename.h > new file mode 100644 > index 0000000000..ecaaa14dba > --- /dev/null > +++ b/sysdeps/generic/arch-fd_to_filename.h > @@ -0,0 +1,19 @@ > +/* Query filename corresponding to an open FD. Generic stub. > + Copyright (C) 2020 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 > + . */ > + > +#error " must be ported to this architecture" > diff --git a/sysdeps/generic/fd_to_filename.h b/sysdeps/generic/fd_to_filename.h > index eff6ca211b..7889db879c 100644 > --- a/sysdeps/generic/fd_to_filename.h > +++ b/sysdeps/generic/fd_to_filename.h > @@ -1,4 +1,4 @@ > -/* Query filename corresponding to an open FD. Generic version. > +/* Query filename corresponding to an open FD. > Copyright (C) 2001-2020 Free Software Foundation, Inc. > This file is part of the GNU C Library. > > @@ -16,12 +16,21 @@ > License along with the GNU C Library; if not, see > . */ > > -#define FD_TO_FILENAME_SIZE 0 > +#ifndef _FD_TO_FILENAME_H > +#define _FD_TO_FILENAME_H > > -/* In general there is no generic way to query filename for an open > - file descriptor. */ > -static inline const char * > -fd_to_filename (int fd, char *buf) > +#include > + > +struct fd_to_filename > { > - return NULL; > -} > + /* A positive int value has at most 10 decimal digits. */ > + char buffer[sizeof (FD_TO_FILENAME_PREFIX) + 10]; > +}; > + > +/* Writes a /proc/self/fd-style path for DESCRIPTOR to *STORAGE and > + returns a pointer to the start of the string. DESCRIPTOR must be > + non-negative. */ > +char *__fd_to_filename (int descriptor, struct fd_to_filename *storage) > + attribute_hidden; > + > +#endif /* _FD_TO_FILENAME_H */ > diff --git a/sysdeps/mach/hurd/arch-fd_to_filename.h b/sysdeps/mach/hurd/arch-fd_to_filename.h > new file mode 100644 > index 0000000000..b45cd8d836 > --- /dev/null > +++ b/sysdeps/mach/hurd/arch-fd_to_filename.h > @@ -0,0 +1,19 @@ > +/* Query filename corresponding to an open FD. Hurd version. > + Copyright (C) 2020 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 > + . */ > + > +#define FD_TO_FILENAME_PREFIX "/dev/fd/" > diff --git a/sysdeps/unix/sysv/linux/fd_to_filename.h b/sysdeps/unix/sysv/linux/arch-fd_to_filename.h > similarity index 58% > rename from sysdeps/unix/sysv/linux/fd_to_filename.h > rename to sysdeps/unix/sysv/linux/arch-fd_to_filename.h > index 92a5e02976..b6017214c7 100644 > --- a/sysdeps/unix/sysv/linux/fd_to_filename.h > +++ b/sysdeps/unix/sysv/linux/arch-fd_to_filename.h > @@ -1,5 +1,5 @@ > /* Query filename corresponding to an open FD. Linux version. > - Copyright (C) 2001-2020 Free Software Foundation, Inc. > + Copyright (C) 2020 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 > @@ -16,22 +16,4 @@ > License along with the GNU C Library; if not, see > . */ > > -#include > -#include > -#include <_itoa.h> > - > -#define FD_TO_FILENAME_SIZE ((sizeof ("/proc/self/fd/") - 1) \ > - + (sizeof ("4294967295") - 1) + 1) > - > -static inline const char * > -fd_to_filename (unsigned int fd, char *buf) > -{ > - *_fitoa_word (fd, __stpcpy (buf, "/proc/self/fd/"), 10, 0) = '\0'; > - > - /* We must make sure the file exists. */ > - struct stat64 st; > - if (__lxstat64 (_STAT_VER, buf, &st) < 0) > - /* /proc is not mounted or something else happened. */ > - return NULL; > - return buf; > -} > +#define FD_TO_FILENAME_PREFIX "/proc/self/fd/" >