From 02191c903188162a48f57a4644dcd74809011151 Mon Sep 17 00:00:00 2001 From: Florian Weimer Date: Fri, 14 Apr 2017 10:30:01 +0200 Subject: Assume that accept4 is always available and works Simplify the Linux accept4 implementation based on the assumption that it is available in some way. __ASSUME_ACCEPT4_SOCKETCALL was previously unused, so remove it. Its functionality is implied by the complex #if condition in accept4.c. --- ChangeLog | 30 ++++++ INSTALL | 30 +++--- manual/install.texi | 32 +++--- nscd/connections.c | 50 +--------- socket/Makefile | 2 + socket/tst-accept4.c | 129 +++++++++++++++++++++++++ support/Makefile | 1 + support/xaccept4.c | 32 ++++++ support/xsocket.h | 1 + sysdeps/mach/hurd/kernel-features.h | 2 - sysdeps/nacl/kernel-features.h | 4 - sysdeps/unix/sysv/linux/accept4.c | 69 ++----------- sysdeps/unix/sysv/linux/ia64/kernel-features.h | 7 +- sysdeps/unix/sysv/linux/kernel-features.h | 11 +-- 14 files changed, 239 insertions(+), 161 deletions(-) create mode 100644 socket/tst-accept4.c create mode 100644 support/xaccept4.c diff --git a/ChangeLog b/ChangeLog index e8e5b98f0e..1085153d1a 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,33 @@ +2017-04-14 Florian Weimer + + * nscd/connections.c (have_accept4): Removed definition. + (nscd_run_worker, main_loop_poll, main_loop_epolll): Assume that + accept4 works. + * manual/install.texi (Linux): Require at least kernel 3.2.18 for + ia64 because that was the first version with accept4 support. + * support/Makefile (libsupport-routines): Add xaccept4. + * support/xsocket.h (xaccept4): Declare. + * support/xaccept4.c: New file. + * socket/tst-accept4.c: New file. + * socket/Makefile (tests): Add tst-accept4. + * sysdeps/mach/hurd/kernel-features.h (__ASSUME_ACCEPT4): Remove + definition. + * sysdeps/nacl/kernel-features.h (__ASSUME_ACCEPT4): Remove + comment. + * sysdeps/unix/sysv/linux/accept4.c: Assume that an accept4 + implementation is available. + (accept4): Use the system call if available, otherwise use the + socket call. + * sysdeps/unix/sysv/linux/ia64/kernel-features.h + (__ASSUME_ACCEPT4_SYSCALL, __ASSUME_ACCEPT4): Do not undefine. + accept4 is unconditionally available in later 3.2 stable kernels. + (__ASSUME_ACCEPT4_SYSCALL): Define. + * sysdeps/unix/sysv/linux/kernel-features.h + (__ASSUME_ACCEPT4_SOCKETCALL, __ASSUME_ACCEPT4): Remove + definitions. + * sysdeps/unix/sysv/linux/i386/kernel-features.h + (__ASSUME_ACCEPT4_SYSCALL): Define for Linux 4.3 or later. + 2017-04-13 Florian Weimer * elf/dl-misc.c (_dl_sysdep_read_whole_file): Assume that diff --git a/INSTALL b/INSTALL index 60f714e0df..51989b21ae 100644 --- a/INSTALL +++ b/INSTALL @@ -500,21 +500,21 @@ Specific advice for GNU/Linux systems ===================================== If you are installing the GNU C Library on GNU/Linux systems, you need -to have the header files from a 3.2 or newer kernel around for -reference. These headers must be installed using 'make -headers_install'; the headers present in the kernel source directory are -not suitable for direct use by the GNU C Library. You do not need to -use that kernel, just have its headers installed where the GNU C Library -can access them, referred to here as INSTALL-DIRECTORY. The easiest way -to do this is to unpack it in a directory such as -'/usr/src/linux-VERSION'. In that directory, run 'make headers_install -INSTALL_HDR_PATH=INSTALL-DIRECTORY'. Finally, configure the GNU C -Library with the option '--with-headers=INSTALL-DIRECTORY/include'. Use -the most recent kernel you can get your hands on. (If you are -cross-compiling the GNU C Library, you need to specify -'ARCH=ARCHITECTURE' in the 'make headers_install' command, where -ARCHITECTURE is the architecture name used by the Linux kernel, such as -'x86' or 'powerpc'.) +to have the header files from a 3.2 or newer kernel (a 3.2.18 or newer +kernel for the ia64 architecture) around for reference. These headers +must be installed using 'make headers_install'; the headers present in +the kernel source directory are not suitable for direct use by the GNU C +Library. You do not need to use that kernel, just have its headers +installed where the GNU C Library can access them, referred to here as +INSTALL-DIRECTORY. The easiest way to do this is to unpack it in a +directory such as '/usr/src/linux-VERSION'. In that directory, run +'make headers_install INSTALL_HDR_PATH=INSTALL-DIRECTORY'. Finally, +configure the GNU C Library with the option +'--with-headers=INSTALL-DIRECTORY/include'. Use the most recent kernel +you can get your hands on. (If you are cross-compiling the GNU C +Library, you need to specify 'ARCH=ARCHITECTURE' in the 'make +headers_install' command, where ARCHITECTURE is the architecture name +used by the Linux kernel, such as 'x86' or 'powerpc'.) After installing the GNU C Library, you may need to remove or rename directories such as '/usr/include/linux' and '/usr/include/asm', and diff --git a/manual/install.texi b/manual/install.texi index 99397c2ee0..43eafa3639 100644 --- a/manual/install.texi +++ b/manual/install.texi @@ -564,22 +564,24 @@ patches, although we try to avoid this. @appendixsec Specific advice for @gnulinuxsystems{} @cindex kernel header files -If you are installing @theglibc{} on @gnulinuxsystems{}, you need to have -the header files from a 3.2 or newer kernel around for reference. -These headers must be installed using @samp{make headers_install}; the -headers present in the kernel source directory are not suitable for -direct use by @theglibc{}. You do not need to use that kernel, just have -its headers installed where @theglibc{} can access them, referred to here as -@var{install-directory}. The easiest way to do this is to unpack it -in a directory such as @file{/usr/src/linux-@var{version}}. In that +If you are installing @theglibc{} on @gnulinuxsystems{}, you need to +have the header files from a 3.2 or newer kernel (a 3.2.18 or newer +kernel for the ia64 architecture) around for reference. These headers +must be installed using @samp{make headers_install}; the headers present +in the kernel source directory are not suitable for direct use by +@theglibc{}. You do not need to use that kernel, just have its headers +installed where @theglibc{} can access them, referred to here as +@var{install-directory}. The easiest way to do this is to unpack it in +a directory such as @file{/usr/src/linux-@var{version}}. In that directory, run @samp{make headers_install -INSTALL_HDR_PATH=@var{install-directory}}. Finally, configure @theglibc{} -with the option @samp{--with-headers=@var{install-directory}/include}. -Use the most recent kernel you can get your hands on. (If you are -cross-compiling @theglibc{}, you need to specify -@samp{ARCH=@var{architecture}} in the @samp{make headers_install} -command, where @var{architecture} is the architecture name used by the -Linux kernel, such as @samp{x86} or @samp{powerpc}.) +INSTALL_HDR_PATH=@var{install-directory}}. Finally, configure +@theglibc{} with the option +@samp{--with-headers=@var{install-directory}/include}. Use the most +recent kernel you can get your hands on. (If you are cross-compiling +@theglibc{}, you need to specify @samp{ARCH=@var{architecture}} in the +@samp{make headers_install} command, where @var{architecture} is the +architecture name used by the Linux kernel, such as @samp{x86} or +@samp{powerpc}.) After installing @theglibc{}, you may need to remove or rename directories such as @file{/usr/include/linux} and diff --git a/nscd/connections.c b/nscd/connections.c index a5ca57aea5..cc1ed72077 100644 --- a/nscd/connections.c +++ b/nscd/connections.c @@ -257,10 +257,6 @@ int inotify_fd = -1; static int nl_status_fd = -1; #endif -#ifndef __ASSUME_ACCEPT4 -static int have_accept4; -#endif - /* Number of times clients had to wait. */ unsigned long int client_queued; @@ -1650,16 +1646,6 @@ nscd_run_worker (void *p) /* We are done with the list. */ pthread_mutex_unlock (&readylist_lock); -#ifndef __ASSUME_ACCEPT4 - if (have_accept4 < 0) - { - /* We do not want to block on a short read or so. */ - int fl = fcntl (fd, F_GETFL); - if (fl == -1 || fcntl (fd, F_SETFL, fl | O_NONBLOCK) == -1) - goto close_and_out; - } -#endif - /* Now read the request. */ request_header req; if (__builtin_expect (TEMP_FAILURE_RETRY (read (fd, &req, sizeof (req))) @@ -2099,24 +2085,8 @@ main_loop_poll (void) if (conns[0].revents != 0) { /* We have a new incoming connection. Accept the connection. */ - int fd; - -#ifndef __ASSUME_ACCEPT4 - fd = -1; - if (have_accept4 >= 0) -#endif - { - fd = TEMP_FAILURE_RETRY (accept4 (sock, NULL, NULL, + int fd = TEMP_FAILURE_RETRY (accept4 (sock, NULL, NULL, SOCK_NONBLOCK)); -#ifndef __ASSUME_ACCEPT4 - if (have_accept4 == 0) - have_accept4 = fd != -1 || errno != ENOSYS ? 1 : -1; -#endif - } -#ifndef __ASSUME_ACCEPT4 - if (have_accept4 < 0) - fd = TEMP_FAILURE_RETRY (accept (sock, NULL, NULL)); -#endif /* Use the descriptor if we have not reached the limit. */ if (fd >= 0) @@ -2284,24 +2254,8 @@ main_loop_epoll (int efd) if (revs[cnt].data.fd == sock) { /* A new connection. */ - int fd; - -# ifndef __ASSUME_ACCEPT4 - fd = -1; - if (have_accept4 >= 0) -# endif - { - fd = TEMP_FAILURE_RETRY (accept4 (sock, NULL, NULL, + int fd = TEMP_FAILURE_RETRY (accept4 (sock, NULL, NULL, SOCK_NONBLOCK)); -# ifndef __ASSUME_ACCEPT4 - if (have_accept4 == 0) - have_accept4 = fd != -1 || errno != ENOSYS ? 1 : -1; -# endif - } -# ifndef __ASSUME_ACCEPT4 - if (have_accept4 < 0) - fd = TEMP_FAILURE_RETRY (accept (sock, NULL, NULL)); -# endif /* Use the descriptor if we have not reached the limit. */ if (fd >= 0) diff --git a/socket/Makefile b/socket/Makefile index 25d4f68578..1e2555d66d 100644 --- a/socket/Makefile +++ b/socket/Makefile @@ -31,6 +31,8 @@ routines := accept bind connect getpeername getsockname getsockopt \ setsockopt shutdown socket socketpair isfdtype opensock \ sockatmark accept4 recvmmsg sendmmsg +tests := tst-accept4 + aux := sa_len include ../Rules diff --git a/socket/tst-accept4.c b/socket/tst-accept4.c new file mode 100644 index 0000000000..c096e8c81b --- /dev/null +++ b/socket/tst-accept4.c @@ -0,0 +1,129 @@ +/* Copyright (C) 2017 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 +#include +#include + +static bool +is_nonblocking (int fd) +{ + int status = fcntl (fd, F_GETFL); + if (status < 0) + FAIL_EXIT1 ("fcntl (F_GETFL): %m"); + return status & O_NONBLOCK; +} + +static bool +is_cloexec (int fd) +{ + int status = fcntl (fd, F_GETFD); + if (status < 0) + FAIL_EXIT1 ("fcntl (F_GETFD): %m"); + return status & FD_CLOEXEC; +} + +struct client +{ + int socket; + struct sockaddr_in address; +}; + +/* Perform a non-blocking connect to *SERVER_ADDRESS. */ +static struct client +client_connect (const struct sockaddr_in *server_address) +{ + struct client result; + result.socket = xsocket (AF_INET, + SOCK_STREAM | SOCK_NONBLOCK | SOCK_CLOEXEC, 0); + TEST_VERIFY (is_nonblocking (result.socket)); + TEST_VERIFY (is_cloexec (result.socket)); + int ret = connect (result.socket, (const struct sockaddr *) server_address, + sizeof (*server_address)); + if (ret < 0 && errno != EINPROGRESS) + FAIL_EXIT1 ("client connect: %m"); + socklen_t sa_len = sizeof (result.address); + xgetsockname (result.socket, (struct sockaddr *) &result.address, + &sa_len); + TEST_VERIFY (sa_len == sizeof (result.address)); + return result; +} + +static void +check_same_address (const struct sockaddr_in *left, + const struct sockaddr_in *right) +{ + TEST_VERIFY (left->sin_family == AF_INET); + TEST_VERIFY (right->sin_family == AF_INET); + TEST_VERIFY (left->sin_addr.s_addr == right->sin_addr.s_addr); + TEST_VERIFY (left->sin_port == right->sin_port); +} + +static int +do_test (void) +{ + /* Create server socket. */ + int server_socket = xsocket (AF_INET, SOCK_STREAM, 0); + TEST_VERIFY (!is_nonblocking (server_socket)); + TEST_VERIFY (!is_cloexec (server_socket)); + struct sockaddr_in server_address = + { + .sin_family = AF_INET, + .sin_addr = {.s_addr = htonl (INADDR_LOOPBACK) }, + }; + xbind (server_socket, + (struct sockaddr *) &server_address, sizeof (server_address)); + { + socklen_t sa_len = sizeof (server_address); + xgetsockname (server_socket, (struct sockaddr *) &server_address, + &sa_len); + TEST_VERIFY (sa_len == sizeof (server_address)); + } + xlisten (server_socket, 5); + + for (int do_nonblock = 0; do_nonblock < 2; ++do_nonblock) + for (int do_cloexec = 0; do_cloexec < 2; ++do_cloexec) + { + int sockflags = 0; + if (do_nonblock) + sockflags |= SOCK_NONBLOCK; + if (do_cloexec) + sockflags |= SOCK_CLOEXEC; + + struct client client = client_connect (&server_address); + struct sockaddr_in client_address; + socklen_t sa_len = sizeof (client_address); + int client_socket = xaccept4 (server_socket, + (struct sockaddr *) &client_address, + &sa_len, sockflags); + TEST_VERIFY (sa_len == sizeof (client_address)); + TEST_VERIFY (is_nonblocking (client_socket) == do_nonblock); + TEST_VERIFY (is_cloexec (client_socket) == do_cloexec); + check_same_address (&client.address, &client_address); + xclose (client_socket); + xclose (client.socket); + } + + return 0; +} + +#include diff --git a/support/Makefile b/support/Makefile index 1f33fa0c74..38dbd832e9 100644 --- a/support/Makefile +++ b/support/Makefile @@ -50,6 +50,7 @@ libsupport-routines = \ temp_file \ write_message \ xaccept \ + xaccept4 \ xasprintf \ xbind \ xcalloc \ diff --git a/support/xaccept4.c b/support/xaccept4.c new file mode 100644 index 0000000000..b676b58ed6 --- /dev/null +++ b/support/xaccept4.c @@ -0,0 +1,32 @@ +/* accept with error checking. + Copyright (C) 2016-2017 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 + +int +xaccept4 (int fd, struct sockaddr *sa, socklen_t *salen, int flags) +{ + int clientfd = accept4 (fd, sa, salen, flags); + if (clientfd < 0) + FAIL_EXIT1 ("accept4 (%d, 0x%x): %m", fd, flags); + return clientfd; +} diff --git a/support/xsocket.h b/support/xsocket.h index 0dbf13ace9..d6724948d8 100644 --- a/support/xsocket.h +++ b/support/xsocket.h @@ -30,6 +30,7 @@ void xconnect (int, const struct sockaddr *, socklen_t); void xbind (int, const struct sockaddr *, socklen_t); void xlisten (int, int); int xaccept (int, struct sockaddr *, socklen_t *); +int xaccept4 (int, struct sockaddr *, socklen_t *, int); void xsendto (int, const void *, size_t, int, const struct sockaddr *, socklen_t); size_t xrecvfrom (int, void *, size_t, int, struct sockaddr *, socklen_t *); diff --git a/sysdeps/mach/hurd/kernel-features.h b/sysdeps/mach/hurd/kernel-features.h index 20cb3ba7bf..196638829f 100644 --- a/sysdeps/mach/hurd/kernel-features.h +++ b/sysdeps/mach/hurd/kernel-features.h @@ -19,5 +19,3 @@ /* This file can define __ASSUME_* macros checked by certain source files. Almost none of these are used outside of sysdeps/unix/sysv/linux code. But those referring to POSIX-level features like O_* flags can be. */ - -#define __ASSUME_ACCEPT4 1 diff --git a/sysdeps/nacl/kernel-features.h b/sysdeps/nacl/kernel-features.h index 32834fd792..ba315b6638 100644 --- a/sysdeps/nacl/kernel-features.h +++ b/sysdeps/nacl/kernel-features.h @@ -19,7 +19,3 @@ /* This file can define __ASSUME_* macros checked by certain source files. Almost none of these are used outside of sysdeps/unix/sysv/linux code. But those referring to POSIX-level features like O_* flags can be. */ - -/* -#define __ASSUME_ACCEPT4 1 -*/ diff --git a/sysdeps/unix/sysv/linux/accept4.c b/sysdeps/unix/sysv/linux/accept4.c index 53afd7a510..0592f43dd6 100644 --- a/sysdeps/unix/sysv/linux/accept4.c +++ b/sysdeps/unix/sysv/linux/accept4.c @@ -22,75 +22,20 @@ #include #include +#include #include +int +accept4 (int fd, __SOCKADDR_ARG addr, socklen_t *addr_len, int flags) +{ /* Do not use the accept4 syscall on socketcall architectures unless it was added at the same time as the socketcall support or can be assumed to be present. */ #if defined __ASSUME_SOCKETCALL \ && !defined __ASSUME_ACCEPT4_SYSCALL_WITH_SOCKETCALL \ && !defined __ASSUME_ACCEPT4_SYSCALL -# undef __NR_accept4 -#endif - -#ifdef __NR_accept4 -int -accept4 (int fd, __SOCKADDR_ARG addr, socklen_t *addr_len, int flags) -{ - return SYSCALL_CANCEL (accept4, fd, addr.__sockaddr__, addr_len, flags); -} -#elif defined __NR_socketcall -# include -# ifdef __ASSUME_ACCEPT4_SOCKETCALL -int -accept4 (int fd, __SOCKADDR_ARG addr, socklen_t *addr_len, int flags) -{ return SOCKETCALL_CANCEL (accept4, fd, addr.__sockaddr__, addr_len, flags); -} -# else -static int have_accept4; - -int -accept4 (int fd, __SOCKADDR_ARG addr, socklen_t *addr_len, int flags) -{ - if (__glibc_likely (have_accept4 >= 0)) - { - int ret = SOCKETCALL_CANCEL (accept4, fd, addr.__sockaddr__, addr_len, - flags); - /* The kernel returns -EINVAL for unknown socket operations. - We need to convert that error to an ENOSYS error. */ - if (__builtin_expect (ret < 0, 0) - && have_accept4 == 0 - && errno == EINVAL) - { - /* Try another call, this time with the FLAGS parameter - cleared and an invalid file descriptor. This call will not - cause any harm and it will return immediately. */ - ret = SOCKETCALL_CANCEL (invalid, -1); - if (errno == EINVAL) - { - have_accept4 = -1; - __set_errno (ENOSYS); - } - else - { - have_accept4 = 1; - __set_errno (EINVAL); - } - return -1; - } - return ret; - } - __set_errno (ENOSYS); - return -1; -} -# endif /* __ASSUME_ACCEPT4_SOCKETCALL */ -#else /* __NR_socketcall */ -int -accept4 (int fd, __SOCKADDR_ARG addr, socklen_t *addr_len, int flags) -{ - __set_errno (ENOSYS); - return -1; -} -stub_warning (accept4) +#else + return SYSCALL_CANCEL (accept4, fd, addr.__sockaddr__, addr_len, flags); #endif +} diff --git a/sysdeps/unix/sysv/linux/ia64/kernel-features.h b/sysdeps/unix/sysv/linux/ia64/kernel-features.h index ac9403e869..cda0ad6150 100644 --- a/sysdeps/unix/sysv/linux/ia64/kernel-features.h +++ b/sysdeps/unix/sysv/linux/ia64/kernel-features.h @@ -22,13 +22,8 @@ #include_next -/* Support for the accept4 syscall was added in 3.3. */ -#if __LINUX_KERNEL_VERSION < 0x030300 -# undef __ASSUME_ACCEPT4_SYSCALL -# undef __ASSUME_ACCEPT4 -#endif - #define __ASSUME_RECV_SYSCALL 1 #define __ASSUME_SEND_SYSCALL 1 +#define __ASSUME_ACCEPT4_SYSCALL 1 #endif /* _KERNEL_FEATURES_H */ diff --git a/sysdeps/unix/sysv/linux/kernel-features.h b/sysdeps/unix/sysv/linux/kernel-features.h index fd936c5366..b981466f34 100644 --- a/sysdeps/unix/sysv/linux/kernel-features.h +++ b/sysdeps/unix/sysv/linux/kernel-features.h @@ -75,18 +75,11 @@ architectures using a separate syscall rather than socketcall that syscall was only added later, and some architectures first had socketcall support then a separate syscall. Define - __ASSUME_ACCEPT4_SOCKETCALL if glibc uses socketcall on this - architecture and accept4 is available through socketcall, __ASSUME_ACCEPT4_SYSCALL if it is available through a separate - syscall, __ASSUME_ACCEPT4_SYSCALL_WITH_SOCKETCALL if it became + syscall, and __ASSUME_ACCEPT4_SYSCALL_WITH_SOCKETCALL if it became available through a separate syscall at the same time as through - socketcall, and __ASSUME_ACCEPT4 if the accept4 function is known - to work. */ -#ifdef __ASSUME_SOCKETCALL -# define __ASSUME_ACCEPT4_SOCKETCALL 1 -#endif + socketcall. */ #define __ASSUME_ACCEPT4_SYSCALL 1 -#define __ASSUME_ACCEPT4 1 /* Support for the FUTEX_CLOCK_REALTIME flag was added in 2.6.29. */ #define __ASSUME_FUTEX_CLOCK_REALTIME 1 -- cgit v1.2.1