Commit 524fa340 authored by Laurent Vivier's avatar Laurent Vivier
Browse files

linux-user: emulate msgsnd(), msgrcv() and semtimedop() 



When we have updated kernel headers to 5.2-rc1 we have introduced
new syscall numbers that can be not supported by older kernels
and fail with ENOSYS while the guest emulation succeeded before
because the syscalls were emulated with ipc().

This patch fixes the problem by using ipc() if the new syscall
returns ENOSYS.

Fixes: 86e63695 ("linux-user: fix __NR_semtimedop undeclared error")
Signed-off-by: default avatarLaurent Vivier <laurent@vivier.eu>
Reviewed-by: default avatarCornelia Huck <cohuck@redhat.com>
Message-Id: <20190529084804.25950-1-laurent@vivier.eu>
Signed-off-by: default avatarLaurent Vivier <laurent@vivier.eu>
parent f3a8bdc1

linux-user/syscall.c

+30 −31
Original line number Diff line number Diff line
@@ -762,50 +762,21 @@ safe_syscall2(int, nanosleep, const struct timespec *, req, 
safe_syscall4(int, clock_nanosleep, const clockid_t, clock, int, flags,

              const struct timespec *, req, struct timespec *, rem)

#endif

#if !defined(__NR_msgsnd) || !defined(__NR_msgrcv) || !defined(__NR_semtimedop)

/* This host kernel architecture uses a single ipc syscall; fake up

 * wrappers for the sub-operations to hide this implementation detail.

 * Annoyingly we can't include linux/ipc.h to get the constant definitions

 * for the call parameter because some structs in there conflict with the

 * sys/ipc.h ones. So we just define them here, and rely on them being

 * the same for all host architectures.

 */

#define Q_SEMTIMEDOP 4

#define Q_MSGSND 11

#define Q_MSGRCV 12

#define Q_IPCCALL(VERSION, OP) ((VERSION) << 16 | (OP))



#ifdef __NR_ipc

safe_syscall6(int, ipc, int, call, long, first, long, second, long, third,

              void *, ptr, long, fifth)

#endif

#ifdef __NR_msgsnd

safe_syscall4(int, msgsnd, int, msgid, const void *, msgp, size_t, sz,

              int, flags)

#else

static int safe_msgsnd(int msgid, const void *msgp, size_t sz, int flags)

{

    return safe_ipc(Q_IPCCALL(0, Q_MSGSND), msgid, sz, flags, (void *)msgp, 0);

}

#endif

#ifdef __NR_msgrcv

safe_syscall5(int, msgrcv, int, msgid, void *, msgp, size_t, sz,

              long, msgtype, int, flags)

#else

static int safe_msgrcv(int msgid, void *msgp, size_t sz, long type, int flags)

{

    return safe_ipc(Q_IPCCALL(1, Q_MSGRCV), msgid, sz, flags, msgp, type);

}

#endif

#ifdef __NR_semtimedop

safe_syscall4(int, semtimedop, int, semid, struct sembuf *, tsops,

              unsigned, nsops, const struct timespec *, timeout)

#else

static int safe_semtimedop(int semid, struct sembuf *tsops, unsigned nsops,

                           const struct timespec *timeout)

{

    return safe_ipc(Q_IPCCALL(0, Q_SEMTIMEDOP), semid, nsops, 0, tsops,

                    (long)timeout);

}

#endif

#if defined(TARGET_NR_mq_open) && defined(__NR_mq_open)

safe_syscall5(int, mq_timedsend, int, mqdes, const char *, msg_ptr,
@@ -3529,11 +3500,21 @@ static inline abi_long target_to_host_sembuf(struct sembuf *host_sembuf, 
static inline abi_long do_semop(int semid, abi_long ptr, unsigned nsops)

{

    struct sembuf sops[nsops];

    abi_long ret;



    if (target_to_host_sembuf(sops, ptr, nsops))

        return -TARGET_EFAULT;



    return get_errno(safe_semtimedop(semid, sops, nsops, NULL));

    ret = -TARGET_ENOSYS;

#ifdef __NR_semtimedop

    ret = get_errno(safe_semtimedop(semid, sops, nsops, NULL));

#endif

#ifdef __NR_ipc

    if (ret == -TARGET_ENOSYS) {

        ret = get_errno(safe_ipc(IPCOP_semtimedop, semid, nsops, 0, sops, 0));

    }

#endif

    return ret;

}



struct target_msqid_ds
@@ -3688,7 +3669,16 @@ static inline abi_long do_msgsnd(int msqid, abi_long msgp, 
    }

    host_mb->mtype = (abi_long) tswapal(target_mb->mtype);

    memcpy(host_mb->mtext, target_mb->mtext, msgsz);

    ret = -TARGET_ENOSYS;

#ifdef __NR_msgsnd

    ret = get_errno(safe_msgsnd(msqid, host_mb, msgsz, msgflg));

#endif

#ifdef __NR_ipc

    if (ret == -TARGET_ENOSYS) {

        ret = get_errno(safe_ipc(IPCOP_msgsnd, msqid, msgsz, msgflg,

                                 host_mb, 0));

    }

#endif

    g_free(host_mb);

    unlock_user_struct(target_mb, msgp, 0);
@@ -3716,7 +3706,16 @@ static inline abi_long do_msgrcv(int msqid, abi_long msgp, 
        ret = -TARGET_ENOMEM;

        goto end;

    }

    ret = -TARGET_ENOSYS;

#ifdef __NR_msgrcv

    ret = get_errno(safe_msgrcv(msqid, host_mb, msgsz, msgtyp, msgflg));

#endif

#ifdef __NR_ipc

    if (ret == -TARGET_ENOSYS) {

        ret = get_errno(safe_ipc(IPCOP_CALL(1, IPCOP_msgrcv), msqid, msgsz,

                        msgflg, host_mb, msgtyp));

    }

#endif



    if (ret > 0) {

        abi_ulong target_mtext_addr = msgp + sizeof(abi_ulong);

linux-user/syscall_defs.h

+1 −0
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ 
#define TARGET_SYS_RECVMMSG     19        /* recvmmsg()            */

#define TARGET_SYS_SENDMMSG     20        /* sendmmsg()            */



#define IPCOP_CALL(VERSION, OP) ((VERSION) << 16 | (OP))

#define IPCOP_semop		1

#define IPCOP_semget		2

#define IPCOP_semctl		3