Re: [PATCH v4 38/53] semihosting: Create semihost_sys_{stat,fstat}

[Luc Michel]

On 13:45 Tue 07 Jun     , Richard Henderson wrote:
> These syscalls will be used by m68k and nios2 semihosting.
> 
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Luc Michel <lmichel@kalray.eu>

> ---
>  include/semihosting/syscalls.h |   7 ++
>  semihosting/syscalls.c         | 137 +++++++++++++++++++++++++++++++++
>  2 files changed, 144 insertions(+)
> 
> diff --git a/include/semihosting/syscalls.h b/include/semihosting/syscalls.h
> index c9f9e66be1..ecc97751a9 100644
> --- a/include/semihosting/syscalls.h
> +++ b/include/semihosting/syscalls.h
> @@ -49,6 +49,13 @@ void semihost_sys_flen(CPUState *cs, 
> gdb_syscall_complete_cb fstat_cb,
>                         gdb_syscall_complete_cb flen_cb,
>                         int fd, target_ulong fstat_addr);
>  
> +void semihost_sys_fstat(CPUState *cs, gdb_syscall_complete_cb complete,
> +                        int fd, target_ulong addr);
> +
> +void semihost_sys_stat(CPUState *cs, gdb_syscall_complete_cb complete,
> +                       target_ulong fname, target_ulong fname_len,
> +                       target_ulong addr);
> +
>  void semihost_sys_remove(CPUState *cs, gdb_syscall_complete_cb complete,
>                           target_ulong fname, target_ulong fname_len);
>  
> diff --git a/semihosting/syscalls.c b/semihosting/syscalls.c
> index de846ced32..d21064716d 100644
> --- a/semihosting/syscalls.c
> +++ b/semihosting/syscalls.c
> @@ -63,6 +63,52 @@ static int validate_lock_user_string(char **pstr, CPUState 
> *cs,
>      return ret;
>  }
>  
> +/*
> + * TODO: Note that gdb always stores the stat structure big-endian.
> + * So far, that's ok, as the only two targets using this are also
> + * big-endian.  Until we do something with gdb, also produce the
> + * same big-endian result from the host.
> + */
> +static int copy_stat_to_user(CPUState *cs, target_ulong addr,
> +                             const struct stat *s)
> +{
> +    CPUArchState *env G_GNUC_UNUSED = cs->env_ptr;
> +    struct gdb_stat *p;
> +
> +    if (s->st_dev != (uint32_t)s->st_dev ||
> +        s->st_ino != (uint32_t)s->st_ino) {
> +        return -EOVERFLOW;
> +    }
> +
> +    p = lock_user(VERIFY_WRITE, addr, sizeof(struct gdb_stat), 0);
> +    if (!p) {
> +        return -EFAULT;
> +    }
> +
> +    p->gdb_st_dev = cpu_to_be32(s->st_dev);
> +    p->gdb_st_ino = cpu_to_be32(s->st_ino);
> +    p->gdb_st_mode = cpu_to_be32(s->st_mode);
> +    p->gdb_st_nlink = cpu_to_be32(s->st_nlink);
> +    p->gdb_st_uid = cpu_to_be32(s->st_uid);
> +    p->gdb_st_gid = cpu_to_be32(s->st_gid);
> +    p->gdb_st_rdev = cpu_to_be32(s->st_rdev);
> +    p->gdb_st_size = cpu_to_be64(s->st_size);
> +#ifdef _WIN32
> +    /* Windows stat is missing some fields.  */
> +    p->gdb_st_blksize = 0;
> +    p->gdb_st_blocks = 0;
> +#else
> +    p->gdb_st_blksize = cpu_to_be64(s->st_blksize);
> +    p->gdb_st_blocks = cpu_to_be64(s->st_blocks);
> +#endif
> +    p->gdb_st_atime = cpu_to_be32(s->st_atime);
> +    p->gdb_st_mtime = cpu_to_be32(s->st_mtime);
> +    p->gdb_st_ctime = cpu_to_be32(s->st_ctime);
> +
> +    unlock_user(p, addr, sizeof(struct gdb_stat));
> +    return 0;
> +}
> +
>  /*
>   * GDB semihosting syscall implementations.
>   */
> @@ -133,6 +179,19 @@ static void gdb_fstat(CPUState *cs, 
> gdb_syscall_complete_cb complete,
>      gdb_do_syscall(complete, "fstat,%x,%x", (target_ulong)gf->hostfd, addr);
>  }
>  
> +static void gdb_stat(CPUState *cs, gdb_syscall_complete_cb complete,
> +                     target_ulong fname, target_ulong fname_len,
> +                     target_ulong addr)
> +{
> +    int len = validate_strlen(cs, fname, fname_len);
> +    if (len < 0) {
> +        complete(cs, -1, -len);
> +        return;
> +    }
> +
> +    gdb_do_syscall(complete, "stat,%s,%x", fname, len, addr);
> +}
> +
>  static void gdb_remove(CPUState *cs, gdb_syscall_complete_cb complete,
>                         target_ulong fname, target_ulong fname_len)
>  {
> @@ -321,6 +380,51 @@ static void host_flen(CPUState *cs, 
> gdb_syscall_complete_cb complete,
>      }
>  }
>  
> +static void host_fstat(CPUState *cs, gdb_syscall_complete_cb complete,
> +                       GuestFD *gf, target_ulong addr)
> +{
> +    struct stat buf;
> +    int ret;
> +
> +    ret = fstat(gf->hostfd, &buf);
> +    if (ret) {
> +        complete(cs, -1, errno);
> +        return;
> +    }
> +    ret = copy_stat_to_user(cs, addr, &buf);
> +    complete(cs, ret ? -1 : 0, ret ? -ret : 0);
> +}
> +
> +static void host_stat(CPUState *cs, gdb_syscall_complete_cb complete,
> +                      target_ulong fname, target_ulong fname_len,
> +                      target_ulong addr)
> +{
> +    CPUArchState *env G_GNUC_UNUSED = cs->env_ptr;
> +    struct stat buf;
> +    char *name;
> +    int ret, err;
> +
> +    ret = validate_lock_user_string(&name, cs, fname, fname_len);
> +    if (ret < 0) {
> +        complete(cs, -1, -ret);
> +        return;
> +    }
> +
> +    ret = stat(name, &buf);
> +    if (ret) {
> +        err = errno;
> +    } else {
> +        ret = copy_stat_to_user(cs, addr, &buf);
> +        err = 0;
> +        if (ret < 0) {
> +            err = -ret;
> +            ret = -1;
> +        }
> +    }
> +    complete(cs, ret, err);
> +    unlock_user(name, fname, 0);
> +}
> +
>  static void host_remove(CPUState *cs, gdb_syscall_complete_cb complete,
>                          target_ulong fname, target_ulong fname_len)
>  {
> @@ -629,6 +733,39 @@ void semihost_sys_flen(CPUState *cs, 
> gdb_syscall_complete_cb fstat_cb,
>      }
>  }
>  
> +void semihost_sys_fstat(CPUState *cs, gdb_syscall_complete_cb complete,
> +                        int fd, target_ulong addr)
> +{
> +    GuestFD *gf = get_guestfd(fd);
> +
> +    if (!gf) {
> +        complete(cs, -1, EBADF);
> +        return;
> +    }
> +    switch (gf->type) {
> +    case GuestFDGDB:
> +        gdb_fstat(cs, complete, gf, addr);
> +        break;
> +    case GuestFDHost:
> +        host_fstat(cs, complete, gf, addr);
> +        break;
> +    case GuestFDStatic:
> +    default:
> +        g_assert_not_reached();
> +    }
> +}
> +
> +void semihost_sys_stat(CPUState *cs, gdb_syscall_complete_cb complete,
> +                       target_ulong fname, target_ulong fname_len,
> +                       target_ulong addr)
> +{
> +    if (use_gdb_syscalls()) {
> +        gdb_stat(cs, complete, fname, fname_len, addr);
> +    } else {
> +        host_stat(cs, complete, fname, fname_len, addr);
> +    }
> +}
> +
>  void semihost_sys_remove(CPUState *cs, gdb_syscall_complete_cb complete,
>                           target_ulong fname, target_ulong fname_len)
>  {
> -- 
> 2.34.1
> 
> 
> 
> 
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> 

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