diff options
Diffstat (limited to 'lib/libc/sys/recv.2')
| -rw-r--r-- | lib/libc/sys/recv.2 | 24 |
1 files changed, 19 insertions, 5 deletions
diff --git a/lib/libc/sys/recv.2 b/lib/libc/sys/recv.2 index 66f311f..74f275c 100644 --- a/lib/libc/sys/recv.2 +++ b/lib/libc/sys/recv.2 @@ -28,7 +28,7 @@ .\" @(#)recv.2 8.3 (Berkeley) 2/21/94 .\" $FreeBSD$ .\" -.Dd December 28, 2006 +.Dd September 12, 2012 .Dt RECV 2 .Os .Sh NAME @@ -44,7 +44,7 @@ .Ft ssize_t .Fn recv "int s" "void *buf" "size_t len" "int flags" .Ft ssize_t -.Fn recvfrom "int s" "void * restrict buf" "size_t len" "int flags" "struct sockaddr * restrict from" "socklen_t * restrict fromlen" +.Fn recvfrom "int s" "void *buf" "size_t len" "int flags" "struct sockaddr * restrict from" "socklen_t * restrict fromlen" .Ft ssize_t .Fn recvmsg "int s" "struct msghdr *msg" "int flags" .Sh DESCRIPTION @@ -252,8 +252,21 @@ struct cmsgcred { }; .Ed .Pp -The kernel will fill in the credential information of the sending process -and deliver it to the receiver. +If a sender supplies ancillary data with enough space for the above struct +tagged as +.Dv SCM_CREDS +control message type to the +.Fn sendmsg +system call, then kernel will fill in the credential information of the +sending process and deliver it to the receiver. +Since receiver usually has no control over a sender, this method of retrieving +credential information isn't reliable. +For reliable retrieval of remote side credentials it is advised to use the +.Dv LOCAL_CREDS +socket option on the receiving socket. +See +.Xr unix 4 +for details. .Pp The .Fa msg_flags @@ -322,7 +335,8 @@ address space. .Xr getsockopt 2 , .Xr read 2 , .Xr select 2 , -.Xr socket 2 +.Xr socket 2 , +.Xr unix 4 .Sh HISTORY The .Fn recv |
