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linux: Add fallback for 64-bit time_t SO_TIMESTAMP{NS}

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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>
This commit is contained in:
Adhemerval Zanella 2020-09-07 17:08:46 -03:00
parent 8dfb169c80
commit 13c51549e2
11 changed files with 167 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
include/sys/socket.h
View File

@ -164,5 +164,10 @@ libc_hidden_proto (__libc_sa_len)
libc_hidden_proto (__cmsg_nxthdr)
#ifndef __ASSUME_TIME64_SYSCALLS
extern void __convert_scm_timestamps (struct msghdr *msg, socklen_t msgsize)
attribute_hidden;
#endif
#endif
#endif

2
sysdeps/unix/sysv/linux/Makefile
View File

@ -64,7 +64,7 @@ sysdep_routines += adjtimex clone umount umount2 readahead sysctl \
time64-support pselect32 \
xstat fxstat lxstat xstat64 fxstat64 lxstat64 \
fxstatat fxstatat64 \
xmknod xmknodat
xmknod xmknodat convert_scm_timestamps
CFLAGS-gethostid.c = -fexceptions
CFLAGS-tee.c = -fexceptions -fasynchronous-unwind-tables

95
sysdeps/unix/sysv/linux/convert_scm_timestamps.c Normal file
View File

@ -0,0 +1,95 @@
/* Socket timestamp conversion routines.
Copyright (C) 2021 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
<https://www.gnu.org/licenses/>. */
#include <kernel-features.h>
#ifndef __ASSUME_TIME64_SYSCALLS
# include <stdint.h>
# include <string.h>
# include <sys/socket.h>
# include <socket-constants-time64.h>
/* It converts the first SO_TIMESTAMP or SO_TIMESTAMPNS with 32-bit time and
appends it to the control buffer. 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. */
void
__convert_scm_timestamps (struct msghdr *msg, socklen_t msgsize)
{
if (msg->msg_control == NULL || msg->msg_controllen == 0)
return;
/* The returned control message format for SO_TIMESTAMP_NEW is a
'struct __kernel_sock_timeval' while for SO_TIMESTAMPNS_NEW is a
'struct __kernel_timespec'. In either case it is two uint64_t
members. */
uint64_t tvts[2];
struct cmsghdr *cmsg, *last = NULL;
int type = 0;
for (cmsg = CMSG_FIRSTHDR (msg);
cmsg != NULL;
cmsg = CMSG_NXTHDR (msg, cmsg))
{
if (cmsg->cmsg_level != SOL_SOCKET)
continue;
switch (cmsg->cmsg_type)
{
case COMPAT_SO_TIMESTAMP_OLD:
if (type != 0)
break;
type = COMPAT_SO_TIMESTAMP_NEW;
goto common;
case COMPAT_SO_TIMESTAMPNS_OLD:
type = COMPAT_SO_TIMESTAMPNS_NEW;
/* fallthrough */
common:
memcpy (tvts, CMSG_DATA (cmsg), sizeof (tvts));
break;
}
last = cmsg;
}
if (last == NULL || type == 0)
return;
if (CMSG_SPACE (sizeof tvts) > msgsize - msg->msg_controllen)
{
msg->msg_flags |= MSG_CTRUNC;
return;
}
msg->msg_controllen += CMSG_SPACE (sizeof tvts);
cmsg = CMSG_NXTHDR(msg, last);
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = type;
cmsg->cmsg_len = CMSG_LEN (sizeof tvts);
memcpy (CMSG_DATA (cmsg), tvts, sizeof tvts);
}
#endif

12
sysdeps/unix/sysv/linux/getsockopt.c
View File

@ -70,6 +70,18 @@ getsockopt32 (int fd, int level, int optname, void *optval,
else
memcpy (optval, &tv32, sizeof tv32);
}
break;
case COMPAT_SO_TIMESTAMP_NEW:
case COMPAT_SO_TIMESTAMPNS_NEW:
{
if (optname == COMPAT_SO_TIMESTAMP_NEW)
optname = COMPAT_SO_TIMESTAMP_OLD;
if (optname == COMPAT_SO_TIMESTAMPNS_NEW)
optname = COMPAT_SO_TIMESTAMPNS_OLD;
r = getsockopt_syscall (fd, level, optname, optval, len);
}
break;
}
return r;

5
sysdeps/unix/sysv/linux/hppa/socket-constants-time64.h
View File

@ -27,4 +27,9 @@
#define COMPAT_SO_RCVTIMEO_NEW 16448
#define COMPAT_SO_SNDTIMEO_NEW 16449
#define COMPAT_SO_TIMESTAMP_OLD 0x4012
#define COMPAT_SO_TIMESTAMPNS_OLD 0x4013
#define COMPAT_SO_TIMESTAMP_NEW 0x4038
#define COMPAT_SO_TIMESTAMPNS_NEW 0x4039
#endif

5
sysdeps/unix/sysv/linux/mips/socket-constants-time64.h
View File

@ -27,4 +27,9 @@
#define COMPAT_SO_RCVTIMEO_NEW 66
#define COMPAT_SO_SNDTIMEO_NEW 67
#define COMPAT_SO_TIMESTAMP_OLD 29
#define COMPAT_SO_TIMESTAMPNS_OLD 35
#define COMPAT_SO_TIMESTAMP_NEW 63
#define COMPAT_SO_TIMESTAMPNS_NEW 64
#endif

5
sysdeps/unix/sysv/linux/powerpc/socket-constants-time64.h
View File

@ -27,4 +27,9 @@
#define COMPAT_SO_RCVTIMEO_NEW 66
#define COMPAT_SO_SNDTIMEO_NEW 67
#define COMPAT_SO_TIMESTAMP_OLD 29
#define COMPAT_SO_TIMESTAMPNS_OLD 35
#define COMPAT_SO_TIMESTAMP_NEW 63
#define COMPAT_SO_TIMESTAMPNS_NEW 64
#endif

23
sysdeps/unix/sysv/linux/recvmsg.c
View File

@ -19,16 +19,27 @@
#include <sys/socket.h>
#include <sysdep-cancel.h>
#include <socketcall.h>
#include <shlib-compat.h>
ssize_t
__libc_recvmsg (int fd, struct msghdr *msg, int flags)
{
# ifdef __ASSUME_RECVMSG_SYSCALL
return SYSCALL_CANCEL (recvmsg, fd, msg, flags);
# else
return SOCKETCALL_CANCEL (recvmsg, fd, msg, flags);
# endif
ssize_t r;
#ifndef __ASSUME_TIME64_SYSCALLS
socklen_t orig_controllen = msg->msg_controllen;
#endif
#ifdef __ASSUME_RECVMSG_SYSCALL
r = SYSCALL_CANCEL (recvmsg, fd, msg, flags);
#else
r = SOCKETCALL_CANCEL (recvmsg, fd, msg, flags);
#endif
#ifndef __ASSUME_TIME64_SYSCALLS
if (r >= 0)
__convert_scm_timestamps (msg, orig_controllen);
#endif
return r;
}
weak_alias (__libc_recvmsg, recvmsg)
weak_alias (__libc_recvmsg, __recvmsg)

12
sysdeps/unix/sysv/linux/setsockopt.c
View File

@ -69,6 +69,18 @@ setsockopt32 (int fd, int level, int optname, const void *optval,
r = setsockopt_syscall (fd, level, optname, &tv32, sizeof (tv32));
}
break;
case COMPAT_SO_TIMESTAMP_NEW:
case COMPAT_SO_TIMESTAMPNS_NEW:
{
if (optname == COMPAT_SO_TIMESTAMP_NEW)
optname = COMPAT_SO_TIMESTAMP_OLD;
if (optname == COMPAT_SO_TIMESTAMPNS_NEW)
optname = COMPAT_SO_TIMESTAMPNS_OLD;
r = setsockopt_syscall (fd, level, optname, NULL, 0);
}
break;
}
return r;

5
sysdeps/unix/sysv/linux/socket-constants-time64.h
View File

@ -27,4 +27,9 @@
#define COMPAT_SO_RCVTIMEO_NEW 66
#define COMPAT_SO_SNDTIMEO_NEW 67
#define COMPAT_SO_TIMESTAMP_OLD 29
#define COMPAT_SO_TIMESTAMPNS_OLD 35
#define COMPAT_SO_TIMESTAMP_NEW 63
#define COMPAT_SO_TIMESTAMPNS_NEW 64
#endif

5
sysdeps/unix/sysv/linux/sparc/socket-constants-time64.h
View File

@ -27,4 +27,9 @@
#define COMPAT_SO_RCVTIMEO_NEW 68
#define COMPAT_SO_SNDTIMEO_NEW 69
#define COMPAT_SO_TIMESTAMP_OLD 0x001d
#define COMPAT_SO_TIMESTAMPNS_OLD 0x0021
#define COMPAT_SO_TIMESTAMP_NEW 0x0046
#define COMPAT_SO_TIMESTAMPNS_NEW 0x0042
#endif