Re: [Qemu-devel] [PATCH v5 1/8] linux-user: Add support for adjtimex() syscall

[Riku Voipio <riku.voipio@iki.fi>]

On Wed, Sep 14, 2016 at 10:19:54PM +0200, Aleksandar Markovic wrote:
> From: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
> 
> This patch implements Qemu user mode adjtimex() syscall support.
> 
> Syscall adjtimex() reads and optionally sets parameters for a clock
> adjustment algorithm used in network synchonization or similar scenarios.
> 
> The implementation is based on invocation of host's adjtimex(), and
> its key part is in the correspondent case segment of the main switch
> statement of the function do_syscall(), in file linux-user/syscalls.c.
> Also, support for related structure "timex" is added to the file
> linux-user/syscall_defs.h, based on its definition in Linux kernel. All
> necessary conversions of the data structures from target to host and from
> host to target are covered. Two new functions, target_to_host_timex() and
> host_to_target_timex(), are provided for the purpose of such conversions.
> Moreover, the relevant support for "-strace" Qemu option is included in
> files linux-user/strace.c and linux-user/strace.list.
> 
> This patch also fixes failures of LTP tests adjtimex01 and adjtimex02, if
> executed in Qemu user mode.
> 
> Signed-off-by: Aleksandar Rikalo <aleksandar.rikalo@imgtec.com>
> Signed-off-by: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
> ---
>  linux-user/strace.c       | 12 +++++++
>  linux-user/strace.list    |  2 +-
>  linux-user/syscall.c      | 90 ++++++++++++++++++++++++++++++++++++++++++++++-
>  linux-user/syscall_defs.h | 28 +++++++++++++++
>  4 files changed, 130 insertions(+), 2 deletions(-)
> 
> diff --git a/linux-user/strace.c b/linux-user/strace.c
> index cc10dc4..7ddcaf8 100644
> --- a/linux-user/strace.c
> +++ b/linux-user/strace.c
> @@ -919,6 +919,18 @@ print_access(const struct syscallname *name,
>  }
>  #endif
>  
> +#ifdef TARGET_NR_adjtimex

The ifdef isn't needed, all linux platorms support adjtimex.

> +static void
> +print_adjtimex(const struct syscallname *name,
> +    abi_long arg0, abi_long arg1, abi_long arg2,
> +    abi_long arg3, abi_long arg4, abi_long arg5)
> +{
> +    print_syscall_prologue(name);
> +    print_pointer(arg0, 1);
> +    print_syscall_epilogue(name);
> +}
> +#endif
> +
>  #ifdef TARGET_NR_brk
>  static void
>  print_brk(const struct syscallname *name,
> diff --git a/linux-user/strace.list b/linux-user/strace.list
> index aa967a2..9a665a8 100644
> --- a/linux-user/strace.list
> +++ b/linux-user/strace.list
> @@ -16,7 +16,7 @@
>  { TARGET_NR_add_key, "add_key" , NULL, NULL, NULL },
>  #endif
>  #ifdef TARGET_NR_adjtimex
> -{ TARGET_NR_adjtimex, "adjtimex" , NULL, NULL, NULL },
> +{ TARGET_NR_adjtimex, "adjtimex" , NULL, print_adjtimex, NULL },
>  #endif
>  #ifdef TARGET_NR_afs_syscall
>  { TARGET_NR_afs_syscall, "afs_syscall" , NULL, NULL, NULL },
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index ca06943..5643840 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -35,6 +35,7 @@
>  #include <sys/swap.h>
>  #include <linux/capability.h>
>  #include <sched.h>
> +#include <sys/timex.h>
>  #ifdef __ia64__
>  int __clone2(int (*fn)(void *), void *child_stack_base,
>               size_t stack_size, int flags, void *arg, ...);
> @@ -6578,6 +6579,78 @@ static inline abi_long target_ftruncate64(void *cpu_env, abi_long arg1,
>  }
>  #endif
>  
> +#ifdef TARGET_NR_adjtimex
> +static inline abi_long target_to_host_timex(struct timex *host_buf,
> +                                            abi_long target_addr)
> +{
> +    struct target_timex *target_buf;
> +
> +    if (!lock_user_struct(VERIFY_READ, target_buf, target_addr, 1)) {
> +        return -TARGET_EFAULT;
> +    }
> +
> +    host_buf->modes = tswap32(target_buf->modes);
> +    host_buf->offset = tswapal(target_buf->offset);
> +    host_buf->freq = tswapal(target_buf->freq);
> +    host_buf->maxerror = tswapal(target_buf->maxerror);
> +    host_buf->esterror = tswapal(target_buf->esterror);
> +    host_buf->status = tswap32(target_buf->status);
> +    host_buf->constant = tswapal(target_buf->constant);
> +    host_buf->precision = tswapal(target_buf->precision);
> +    host_buf->tolerance = tswapal(target_buf->tolerance);
> +    host_buf->time.tv_sec = tswapal(target_buf->time.tv_sec);
> +    host_buf->time.tv_usec = tswapal(target_buf->time.tv_usec);
> +    host_buf->tick = tswapal(target_buf->tick);
> +    host_buf->ppsfreq = tswapal(target_buf->ppsfreq);
> +    host_buf->jitter = tswapal(target_buf->jitter);
> +    host_buf->shift = tswap32(target_buf->shift);
> +    host_buf->stabil = tswapal(target_buf->stabil);
> +    host_buf->jitcnt = tswapal(target_buf->jitcnt);
> +    host_buf->calcnt = tswapal(target_buf->calcnt);
> +    host_buf->errcnt = tswapal(target_buf->errcnt);
> +    host_buf->stbcnt = tswapal(target_buf->stbcnt);
> +    host_buf->tai = tswap32(target_buf->tai);
> +
> +    unlock_user_struct(target_buf, target_addr, 0);
> +    return 0;
> +}
> +
> +static inline abi_long host_to_target_timex(abi_long target_addr,
> +                                            struct timex *host_buf)
> +{
> +    struct target_timex *target_buf;
> +
> +    if (!lock_user_struct(VERIFY_WRITE, target_buf, target_addr, 0)) {
> +        return -TARGET_EFAULT;
> +    }
> +
> +    target_buf->modes = tswap32(host_buf->modes);
> +    target_buf->offset = tswapal(host_buf->offset);
> +    target_buf->freq = tswapal(host_buf->freq);
> +    target_buf->maxerror = tswapal(host_buf->maxerror);
> +    target_buf->esterror = tswapal(host_buf->esterror);
> +    target_buf->status = tswap32(host_buf->status);
> +    target_buf->constant = tswapal(host_buf->constant);
> +    target_buf->precision = tswapal(host_buf->precision);
> +    target_buf->tolerance = tswapal(host_buf->tolerance);
> +    target_buf->time.tv_sec = tswapal(host_buf->time.tv_sec);
> +    target_buf->time.tv_usec = tswapal(host_buf->time.tv_usec);
> +    target_buf->tick = tswapal(host_buf->tick);
> +    target_buf->ppsfreq = tswapal(host_buf->ppsfreq);
> +    target_buf->jitter = tswapal(host_buf->jitter);
> +    target_buf->shift = tswap32(host_buf->shift);
> +    target_buf->stabil = tswapal(host_buf->stabil);
> +    target_buf->jitcnt = tswapal(host_buf->jitcnt);
> +    target_buf->calcnt = tswapal(host_buf->calcnt);
> +    target_buf->errcnt = tswapal(host_buf->errcnt);
> +    target_buf->stbcnt = tswapal(host_buf->stbcnt);
> +    target_buf->tai = tswap32(host_buf->tai);
> +
> +    unlock_user_struct(target_buf, target_addr, 1);
> +    return 0;
> +}
> +#endif
> +
>  static inline abi_long target_to_host_timespec(struct timespec *host_ts,
>                                                 abi_ulong target_addr)
>  {
> @@ -9419,8 +9492,23 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
>          break;
>  #endif
>  #endif
> +#ifdef TARGET_NR_adjtimex
>      case TARGET_NR_adjtimex:
> -        goto unimplemented;
> +        {
> +            struct timex host_buf;
> +
> +            if (target_to_host_timex(&host_buf, arg1) != 0) {
> +                goto efault;
> +            }
> +            ret = get_errno(adjtimex(&host_buf));
> +            if (!is_error(ret) && arg1) {
> +                if (host_to_target_timex(arg1, &host_buf) != 0) {
> +                    goto efault;
> +                }
> +            }
> +        }
> +        break;
> +#endif
>  #ifdef TARGET_NR_create_module
>      case TARGET_NR_create_module:
>  #endif
> diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
> index 7835654..afd9191 100644
> --- a/linux-user/syscall_defs.h
> +++ b/linux-user/syscall_defs.h
> @@ -207,6 +207,34 @@ struct target_itimerspec {
>      struct target_timespec it_value;
>  };
>  
> +struct target_timex {
> +    unsigned int modes;          /* Mode selector */
> +    abi_long offset;             /* Time offset */
> +    abi_long freq;               /* Frequency offset */
> +    abi_long maxerror;           /* Maximum error (microseconds) */
> +    abi_long esterror;           /* Estimated error (microseconds) */
> +    int status;                  /* Clock command/status */
> +    abi_long constant;           /* PLL (phase-locked loop) time constant */
> +    abi_long precision;          /* Clock precision (microseconds, ro) */
> +    abi_long tolerance;          /* Clock freq. tolerance (ppm, ro) */
> +    struct target_timeval time;  /* Current time */
> +    abi_long tick;               /* Microseconds between clock ticks */
> +    abi_long ppsfreq;            /* PPS (pulse per second) frequency */
> +    abi_long jitter;             /* PPS jitter (ro); nanoseconds */
> +    int shift;                   /* PPS interval duration (seconds) */
> +    abi_long stabil;             /* PPS stability */
> +    abi_long jitcnt;             /* PPS jitter limit exceeded (ro) */
> +    abi_long calcnt;             /* PPS calibration intervals */
> +    abi_long errcnt;             /* PPS calibration errors */
> +    abi_long stbcnt;             /* PPS stability limit exceeded */
> +    int tai;                     /* TAI offset */
> +
> +    /* Further padding bytes to allow for future expansion */
> +    int:32; int:32; int:32; int:32;
> +    int:32; int:32; int:32; int:32;
> +    int:32; int:32; int:32;
> +};
> +
>  typedef abi_long target_clock_t;
>  
>  #define TARGET_HZ 100
> -- 
> 2.9.3
> 
>