![Ulrich Drepper](/assets/img/avatar_default.png)
This patch is by far the most complex in the series. It adds a new syscall paccept. This syscall differs from accept in that it adds (at the userlevel) two additional parameters: - a signal mask - a flags value The flags parameter can be used to set flag like SOCK_CLOEXEC. This is imlpemented here as well. Some people argued that this is a property which should be inherited from the file desriptor for the server but this is against POSIX. Additionally, we really want the signal mask parameter as well (similar to pselect, ppoll, etc). So an interface change in inevitable. The flag value is the same as for socket and socketpair. I think diverging here will only create confusion. Similar to the filesystem interfaces where the use of the O_* constants differs, it is acceptable here. The signal mask is handled as for pselect etc. The mask is temporarily installed for the thread and removed before the call returns. I modeled the code after pselect. If there is a problem it's likely also in pselect. For architectures which use socketcall I maintained this interface instead of adding a system call. The symmetry shouldn't be broken. The following test must be adjusted for architectures other than x86 and x86-64 and in case the syscall numbers changed. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ #include <errno.h> #include <fcntl.h> #include <pthread.h> #include <signal.h> #include <stdio.h> #include <unistd.h> #include <netinet/in.h> #include <sys/socket.h> #include <sys/syscall.h> #ifndef __NR_paccept # ifdef __x86_64__ # define __NR_paccept 288 # elif defined __i386__ # define SYS_PACCEPT 18 # define USE_SOCKETCALL 1 # else # error "need __NR_paccept" # endif #endif #ifdef USE_SOCKETCALL # define paccept(fd, addr, addrlen, mask, flags) \ ({ long args[6] = { \ (long) fd, (long) addr, (long) addrlen, (long) mask, 8, (long) flags }; \ syscall (__NR_socketcall, SYS_PACCEPT, args); }) #else # define paccept(fd, addr, addrlen, mask, flags) \ syscall (__NR_paccept, fd, addr, addrlen, mask, 8, flags) #endif #define PORT 57392 #define SOCK_CLOEXEC O_CLOEXEC static pthread_barrier_t b; static void * tf (void *arg) { pthread_barrier_wait (&b); int s = socket (AF_INET, SOCK_STREAM, 0); struct sockaddr_in sin; sin.sin_family = AF_INET; sin.sin_addr.s_addr = htonl (INADDR_LOOPBACK); sin.sin_port = htons (PORT); connect (s, (const struct sockaddr *) &sin, sizeof (sin)); close (s); pthread_barrier_wait (&b); s = socket (AF_INET, SOCK_STREAM, 0); sin.sin_port = htons (PORT); connect (s, (const struct sockaddr *) &sin, sizeof (sin)); close (s); pthread_barrier_wait (&b); pthread_barrier_wait (&b); sleep (2); pthread_kill ((pthread_t) arg, SIGUSR1); return NULL; } static void handler (int s) { } int main (void) { pthread_barrier_init (&b, NULL, 2); struct sockaddr_in sin; pthread_t th; if (pthread_create (&th, NULL, tf, (void *) pthread_self ()) != 0) { puts ("pthread_create failed"); return 1; } int s = socket (AF_INET, SOCK_STREAM, 0); int reuse = 1; setsockopt (s, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof (reuse)); sin.sin_family = AF_INET; sin.sin_addr.s_addr = htonl (INADDR_LOOPBACK); sin.sin_port = htons (PORT); bind (s, (struct sockaddr *) &sin, sizeof (sin)); listen (s, SOMAXCONN); pthread_barrier_wait (&b); int s2 = paccept (s, NULL, 0, NULL, 0); if (s2 < 0) { puts ("paccept(0) failed"); return 1; } int coe = fcntl (s2, F_GETFD); if (coe & FD_CLOEXEC) { puts ("paccept(0) set close-on-exec-flag"); return 1; } close (s2); pthread_barrier_wait (&b); s2 = paccept (s, NULL, 0, NULL, SOCK_CLOEXEC); if (s2 < 0) { puts ("paccept(SOCK_CLOEXEC) failed"); return 1; } coe = fcntl (s2, F_GETFD); if ((coe & FD_CLOEXEC) == 0) { puts ("paccept(SOCK_CLOEXEC) does not set close-on-exec flag"); return 1; } close (s2); pthread_barrier_wait (&b); struct sigaction sa; sa.sa_handler = handler; sa.sa_flags = 0; sigemptyset (&sa.sa_mask); sigaction (SIGUSR1, &sa, NULL); sigset_t ss; pthread_sigmask (SIG_SETMASK, NULL, &ss); sigaddset (&ss, SIGUSR1); pthread_sigmask (SIG_SETMASK, &ss, NULL); sigdelset (&ss, SIGUSR1); alarm (4); pthread_barrier_wait (&b); errno = 0 ; s2 = paccept (s, NULL, 0, &ss, 0); if (s2 != -1 || errno != EINTR) { puts ("paccept did not fail with EINTR"); return 1; } close (s); puts ("OK"); return 0; } ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ [akpm@linux-foundation.org: make it compile] [akpm@linux-foundation.org: add sys_ni stub] Signed-off-by: Ulrich Drepper <drepper@redhat.com> Acked-by: Davide Libenzi <davidel@xmailserver.org> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Cc: <linux-arch@vger.kernel.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Roland McGrath <roland@redhat.com> Cc: Kyle McMartin <kyle@mcmartin.ca> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
63 lines
1.5 KiB
C
63 lines
1.5 KiB
C
#ifndef _ASM_SOCKET_H
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#define _ASM_SOCKET_H
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#include <asm/sockios.h>
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/* For setsockopt(2) */
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#define SOL_SOCKET 0xffff
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#define SO_DEBUG 0x0001
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#define SO_REUSEADDR 0x0004
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#define SO_KEEPALIVE 0x0008
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#define SO_DONTROUTE 0x0010
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#define SO_BROADCAST 0x0020
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#define SO_LINGER 0x0080
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#define SO_OOBINLINE 0x0100
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/* To add :#define SO_REUSEPORT 0x0200 */
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#define SO_SNDBUF 0x1001
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#define SO_RCVBUF 0x1002
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#define SO_SNDBUFFORCE 0x100a
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#define SO_RCVBUFFORCE 0x100b
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#define SO_SNDLOWAT 0x1003
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#define SO_RCVLOWAT 0x1004
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#define SO_SNDTIMEO 0x1005
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#define SO_RCVTIMEO 0x1006
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#define SO_ERROR 0x1007
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#define SO_TYPE 0x1008
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#define SO_PEERNAME 0x2000
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#define SO_NO_CHECK 0x400b
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#define SO_PRIORITY 0x400c
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#define SO_BSDCOMPAT 0x400e
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#define SO_PASSCRED 0x4010
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#define SO_PEERCRED 0x4011
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#define SO_TIMESTAMP 0x4012
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#define SCM_TIMESTAMP SO_TIMESTAMP
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#define SO_TIMESTAMPNS 0x4013
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#define SCM_TIMESTAMPNS SO_TIMESTAMPNS
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/* Security levels - as per NRL IPv6 - don't actually do anything */
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#define SO_SECURITY_AUTHENTICATION 0x4016
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#define SO_SECURITY_ENCRYPTION_TRANSPORT 0x4017
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#define SO_SECURITY_ENCRYPTION_NETWORK 0x4018
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#define SO_BINDTODEVICE 0x4019
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/* Socket filtering */
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#define SO_ATTACH_FILTER 0x401a
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#define SO_DETACH_FILTER 0x401b
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#define SO_ACCEPTCONN 0x401c
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#define SO_PEERSEC 0x401d
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#define SO_PASSSEC 0x401e
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#define SO_MARK 0x401f
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/* O_NONBLOCK clashes with the bits used for socket types. Therefore we
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* have to define SOCK_NONBLOCK to a different value here.
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*/
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#define SOCK_NONBLOCK 0x40000000
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#endif /* _ASM_SOCKET_H */
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