man2/socketcall.2

   1 .\" Copyright (c) 1995 Michael Chastain (mec@shell.portal.com), 15 April 1995.
   2 .\"
   3 .\" SPDX-License-Identifier: GPL-2.0-or-later
   4 .\"
   5 .\" Modified Tue Oct 22 22:11:53 1996 by Eric S. Raymond <esr@thyrsus.com>
   6 .TH socketcall 2 (date) "Linux man-pages (unreleased)"
   7 .SH NAME
   8 socketcall \- socket system calls
   9 .SH LIBRARY
  10 Standard C library
  11 .RI ( libc ", " \-lc )
  12 .SH SYNOPSIS
  13 .nf
  14 .BR "#include <linux/net.h>" "        /* Definition of " SYS_* " constants */"
  15 .BR "#include <sys/syscall.h>" "      /* Definition of " SYS_socketcall " */"
  16 .B #include <unistd.h>
  17 .PP
  18 .BI "int syscall(SYS_socketcall, int " call ", unsigned long *" args );
  19 .fi
  20 .PP
  21 .IR Note :
  22 glibc provides no wrapper for
  23 .BR socketcall (),
  24 necessitating the use of
  25 .BR syscall (2).
  26 .SH DESCRIPTION
  27 .BR socketcall ()
  28 is a common kernel entry point for the socket system calls.
  29 .I call
  30 determines which socket function to invoke.
  31 .I args
  32 points to a block containing the actual arguments,
  33 which are passed through to the appropriate call.
  34 .PP
  35 User programs should call the appropriate functions by their usual names.
  36 Only standard library implementors and kernel hackers need to know about
  37 .BR socketcall ().
  38 .PP
  39 .TS
  40 tab(:);
  41 l l.
  42 \fIcall\fR:Man page
  43 T{
  44 .B SYS_SOCKET
  45 T}:T{
  46 .BR socket (2)
  47 T}
  48 T{
  49 .B SYS_BIND
  50 T}:T{
  51 .BR bind (2)
  52 T}
  53 T{
  54 .B SYS_CONNECT
  55 T}:T{
  56 .BR connect (2)
  57 T}
  58 T{
  59 .B SYS_LISTEN
  60 T}:T{
  61 .BR listen (2)
  62 T}
  63 T{
  64 .B SYS_ACCEPT
  65 T}:T{
  66 .BR accept (2)
  67 T}
  68 T{
  69 .B SYS_GETSOCKNAME
  70 T}:T{
  71 .BR getsockname (2)
  72 T}
  73 T{
  74 .B SYS_GETPEERNAME
  75 T}:T{
  76 .BR getpeername (2)
  77 T}
  78 T{
  79 .B SYS_SOCKETPAIR
  80 T}:T{
  81 .BR socketpair (2)
  82 T}
  83 T{
  84 .B SYS_SEND
  85 T}:T{
  86 .BR send (2)
  87 T}
  88 T{
  89 .B SYS_RECV
  90 T}:T{
  91 .BR recv (2)
  92 T}
  93 T{
  94 .B SYS_SENDTO
  95 T}:T{
  96 .BR sendto (2)
  97 T}
  98 T{
  99 .B SYS_RECVFROM
 100 T}:T{
 101 .BR recvfrom (2)
 102 T}
 103 T{
 104 .B SYS_SHUTDOWN
 105 T}:T{
 106 .BR shutdown (2)
 107 T}
 108 T{
 109 .B SYS_SETSOCKOPT
 110 T}:T{
 111 .BR setsockopt (2)
 112 T}
 113 T{
 114 .B SYS_GETSOCKOPT
 115 T}:T{
 116 .BR getsockopt (2)
 117 T}
 118 T{
 119 .B SYS_SENDMSG
 120 T}:T{
 121 .BR sendmsg (2)
 122 T}
 123 T{
 124 .B SYS_RECVMSG
 125 T}:T{
 126 .BR recvmsg (2)
 127 T}
 128 T{
 129 .B SYS_ACCEPT4
 130 T}:T{
 131 .BR accept4 (2)
 132 T}
 133 T{
 134 .B SYS_RECVMMSG
 135 T}:T{
 136 .BR recvmmsg (2)
 137 T}
 138 T{
 139 .B SYS_SENDMMSG
 140 T}:T{
 141 .BR sendmmsg (2)
 142 T}
 143 .TE
 144 .SH STANDARDS
 145 This call is specific to Linux, and should not be used in programs
 146 intended to be portable.
 147 .SH NOTES
 148 On some architectures\(emfor example, x86-64 and ARM\(emthere is no
 149 .BR socketcall ()
 150 system call; instead
 151 .BR socket (2),
 152 .BR accept (2),
 153 .BR bind (2),
 154 and so on really are implemented as separate system calls.
 155 .PP
 156 On x86-32,
 157 .BR socketcall ()
 158 was historically the only entry point for the sockets API.
 159 However, starting in Linux 4.3,
 160 .\" commit 9dea5dc921b5f4045a18c63eb92e84dc274d17eb
 161 direct system calls are provided on x86-32 for the sockets API.
 162 This facilitates the creation of
 163 .BR seccomp (2)
 164 filters that filter sockets system calls
 165 (for new user-space binaries that are compiled
 166 to use the new entry points)
 167 and also provides a (very) small performance improvement.
 168 .SH SEE ALSO
 169 .BR accept (2),
 170 .BR bind (2),
 171 .BR connect (2),
 172 .BR getpeername (2),
 173 .BR getsockname (2),
 174 .BR getsockopt (2),
 175 .BR listen (2),
 176 .BR recv (2),
 177 .BR recvfrom (2),
 178 .BR recvmsg (2),
 179 .BR send (2),
 180 .BR sendmsg (2),
 181 .BR sendto (2),
 182 .BR setsockopt (2),
 183 .BR shutdown (2),
 184 .BR socket (2),
 185 .BR socketpair (2)