[PATCH v2 06/25] linux: Add fallback for 64-bit time_t SO_TIMESTAMP{NS}
Lukasz Majewski
lukma@denx.de
Wed May 19 08:50:10 GMT 2021
On Tue, 18 May 2021 17:55:54 -0300
Adhemerval Zanella <adhemerval.zanella@linaro.org> wrote:
> 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.
>
Reviewed-by: Lukasz Majewski <lukma@denx.de>
> Checked on x86_64-linux-gnu and i686-linux-gnu (on 5.4 and on 4.15
> kernel).
> ---
> include/sys/socket.h | 5 +
> sysdeps/unix/sysv/linux/Makefile | 2 +-
> sysdeps/unix/sysv/linux/Versions | 1 +
> .../unix/sysv/linux/convert_scm_timestamps.c | 96
> +++++++++++++++++++ sysdeps/unix/sysv/linux/getsockopt.c |
> 12 +++ .../sysv/linux/hppa/socket-constants-time64.h | 5 +
> .../sysv/linux/mips/socket-constants-time64.h | 5 +
> .../linux/powerpc/socket-constants-time64.h | 5 +
> sysdeps/unix/sysv/linux/recvmsg.c | 23 +++--
> sysdeps/unix/sysv/linux/setsockopt.c | 12 +++
> .../unix/sysv/linux/socket-constants-time64.h | 5 +
> .../linux/sparc/socket-constants-time64.h | 5 +
> 12 files changed, 169 insertions(+), 7 deletions(-)
> create mode 100644 sysdeps/unix/sysv/linux/convert_scm_timestamps.c
>
> diff --git a/include/sys/socket.h b/include/sys/socket.h
> index 0e39dd2a3a..15d4a62b26 100644
> --- a/include/sys/socket.h
> +++ b/include/sys/socket.h
> @@ -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) ; +libc_hidden_proto (__convert_scm_timestamps)
> +#endif
> +
> #endif
> #endif
> diff --git a/sysdeps/unix/sysv/linux/Makefile
> b/sysdeps/unix/sysv/linux/Makefile index fb155cf856..e28f6470e3 100644
> --- a/sysdeps/unix/sysv/linux/Makefile
> +++ b/sysdeps/unix/sysv/linux/Makefile
> @@ -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
> diff --git a/sysdeps/unix/sysv/linux/Versions
> b/sysdeps/unix/sysv/linux/Versions index 220bb2dffe..148f04c50a 100644
> --- a/sysdeps/unix/sysv/linux/Versions
> +++ b/sysdeps/unix/sysv/linux/Versions
> @@ -177,6 +177,7 @@ libc {
> __pread64_nocancel;
> __close_nocancel;
> __sigtimedwait;
> + __convert_scm_timestamps;
> # functions used by nscd
> __netlink_assert_response;
> }
> diff --git a/sysdeps/unix/sysv/linux/convert_scm_timestamps.c
> b/sysdeps/unix/sysv/linux/convert_scm_timestamps.c new file mode
> 100644 index 0000000000..3c123c28ce
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/convert_scm_timestamps.c
> @@ -0,0 +1,96 @@
> +/* 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);
> +}
> +libc_hidden_def (__convert_scm_timestamps)
> +#endif
> diff --git a/sysdeps/unix/sysv/linux/getsockopt.c
> b/sysdeps/unix/sysv/linux/getsockopt.c index c8e502d976..14b782d0da
> 100644 --- a/sysdeps/unix/sysv/linux/getsockopt.c
> +++ b/sysdeps/unix/sysv/linux/getsockopt.c
> @@ -67,6 +67,18 @@ getsockopt32 (int fd, int level, int optname, void
> *optval, *tv64 = valid_timeval32_to_timeval64 (tv32);
> *len = sizeof (*tv64);
> }
> + 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;
> diff --git a/sysdeps/unix/sysv/linux/hppa/socket-constants-time64.h
> b/sysdeps/unix/sysv/linux/hppa/socket-constants-time64.h index
> ea721e0fc2..f3b98012d5 100644 ---
> a/sysdeps/unix/sysv/linux/hppa/socket-constants-time64.h +++
> b/sysdeps/unix/sysv/linux/hppa/socket-constants-time64.h @@ -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
> diff --git a/sysdeps/unix/sysv/linux/mips/socket-constants-time64.h
> b/sysdeps/unix/sysv/linux/mips/socket-constants-time64.h index
> ab8bd62853..31fa69fa9f 100644 ---
> a/sysdeps/unix/sysv/linux/mips/socket-constants-time64.h +++
> b/sysdeps/unix/sysv/linux/mips/socket-constants-time64.h @@ -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
> diff --git
> a/sysdeps/unix/sysv/linux/powerpc/socket-constants-time64.h
> b/sysdeps/unix/sysv/linux/powerpc/socket-constants-time64.h index
> 1e48dcca8d..889251895b 100644 ---
> a/sysdeps/unix/sysv/linux/powerpc/socket-constants-time64.h +++
> b/sysdeps/unix/sysv/linux/powerpc/socket-constants-time64.h @@ -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
> diff --git a/sysdeps/unix/sysv/linux/recvmsg.c
> b/sysdeps/unix/sysv/linux/recvmsg.c index b209b4ad99..a2a600228b
> 100644 --- a/sysdeps/unix/sysv/linux/recvmsg.c
> +++ b/sysdeps/unix/sysv/linux/recvmsg.c
> @@ -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)
> diff --git a/sysdeps/unix/sysv/linux/setsockopt.c
> b/sysdeps/unix/sysv/linux/setsockopt.c index 6505202265..a4780a9d33
> 100644 --- a/sysdeps/unix/sysv/linux/setsockopt.c
> +++ b/sysdeps/unix/sysv/linux/setsockopt.c
> @@ -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;
> diff --git a/sysdeps/unix/sysv/linux/socket-constants-time64.h
> b/sysdeps/unix/sysv/linux/socket-constants-time64.h index
> e5a3777f28..7f7ca05504 100644 ---
> a/sysdeps/unix/sysv/linux/socket-constants-time64.h +++
> b/sysdeps/unix/sysv/linux/socket-constants-time64.h @@ -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
> diff --git a/sysdeps/unix/sysv/linux/sparc/socket-constants-time64.h
> b/sysdeps/unix/sysv/linux/sparc/socket-constants-time64.h index
> b137abdeea..56358923e1 100644 ---
> a/sysdeps/unix/sysv/linux/sparc/socket-constants-time64.h +++
> b/sysdeps/unix/sysv/linux/sparc/socket-constants-time64.h @@ -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
Best regards,
Lukasz Majewski
--
DENX Software Engineering GmbH, Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de
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