From patchwork Fri Feb 14 18:11:09 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Weimer X-Patchwork-Id: 38081 Received: (qmail 95368 invoked by alias); 14 Feb 2020 18:11:25 -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 Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 95354 invoked by uid 89); 14 Feb 2020 18:11:25 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-19.0 required=5.0 tests=AWL, BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, KAM_SHORT, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 spammy=H*i:sk:cover.1, sk:__buil, sk:!__buil, powers X-HELO: us-smtp-delivery-1.mimecast.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1581703880; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=1fkDqoK8ppEzvDjtRF0P6VIscKbjCN0nHFz5xUfwmMk=; b=CWLnbsvTQd444jtut64S+aj/94Zl/ivdyHVH19NTEqKcXd4uvKQeOJOmgZ8fAaGLnxbN0u A4jha5gaYYfnq56305umsmUvWQDIgvri3gJ5AbF7KrzIZH2OFKNmkay9fKZjDbykHoWQvj kVbyg4UTtDVnZic7RJgqAUiswhilgvE= From: Florian Weimer To: libc-alpha@sourceware.org Cc: Samuel Thibault Subject: [PATCH 1/3] : Add type safety and port to Hurd In-Reply-To: References: X-From-Line: c6b3a5e519cd3b0d7d77c7f2dfe35384b36cb39a Mon Sep 17 00:00:00 2001 Message-Id: Date: Fri, 14 Feb 2020 19:11:09 +0100 User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com The new type struct fd_to_filename makes the allocation of the backing storage explicit. Hurd uses /dev/fd, not /proc/self/fd. Acked-by: Samuel Thibault --- 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; +} 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/"