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13c51549e2
The recvmsg handling is more complicated because it requires check the returned kernel control message and make some convertions. For !__ASSUME_TIME64_SYSCALLS it converts the first 32-bit time SO_TIMESTAMP or SO_TIMESTAMPNS and appends it to the control buffer if has extra space or returns MSG_CTRUNC otherwise. The 32-bit time field is kept as-is. Calls with __TIMESIZE=32 will see the converted 64-bit time control messages as spurious control message of unknown type. Calls with __TIMESIZE=64 running on pre-time64 kernels will see the original message as a spurious control ones of unknown typ while running on kernel with native 64-bit time support will only see the time64 version of the control message. Checked on x86_64-linux-gnu and i686-linux-gnu (on 5.4 and on 4.15 kernel). Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
46 lines
1.4 KiB
C
46 lines
1.4 KiB
C
/* Linux recvmsg syscall wrapper.
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Copyright (C) 2016-2021 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <sys/socket.h>
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#include <sysdep-cancel.h>
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#include <socketcall.h>
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ssize_t
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__libc_recvmsg (int fd, struct msghdr *msg, int flags)
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{
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ssize_t r;
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#ifndef __ASSUME_TIME64_SYSCALLS
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socklen_t orig_controllen = msg->msg_controllen;
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#endif
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#ifdef __ASSUME_RECVMSG_SYSCALL
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r = SYSCALL_CANCEL (recvmsg, fd, msg, flags);
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#else
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r = SOCKETCALL_CANCEL (recvmsg, fd, msg, flags);
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#endif
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#ifndef __ASSUME_TIME64_SYSCALLS
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if (r >= 0)
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__convert_scm_timestamps (msg, orig_controllen);
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#endif
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return r;
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}
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weak_alias (__libc_recvmsg, recvmsg)
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weak_alias (__libc_recvmsg, __recvmsg)
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