[PATCH 1/3] linux: Use INTERNAL_SYSCALL on fstatat{64}

Adhemerval Zanella adhemerval.zanella@linaro.org
Thu Oct 15 12:32:04 GMT 2020



On 14/10/2020 17:37, Adhemerval Zanella wrote:
> Although not required by the standards, some code expects that a
> successful stat call should not set errno.  However since aa03f722f3b99
> 'linux: Add {f}stat{at} y2038 support', stat implementation will first
> try a __NR_statx call and if it fails with ENOSYS then issue the
> required stat syscall.
> 
> On 32-bit architecture running on kernel without __NR_statx support the
> first call will set the errno to ENOSYS, even when the following stat
> syscall does not fail.
> 
> This patch fixes by using INTERNAL_SYSCALL and only setting the errno
> value when function returns.
> 
> Checked on i686-linux-gnu, x86_64-linux-gnu, sparc64-linux-gnu,
> sparcv9-linux-gnu, powerpc64-linux-gnu, powerpc64le-linux-gnu,
> arm-linux-gnueabihf, and aarch64-linux-gnu.

So this also fixes the regressions I was seeing on mips-linux-gnu and
mips64-n32-linux-gnu.  I will commit this shortly if no one opposes.

> ---
>  sysdeps/unix/sysv/linux/fstatat.c             | 28 ++++++++++------
>  sysdeps/unix/sysv/linux/fstatat64.c           | 33 ++++++++++---------
>  .../unix/sysv/linux/mips/mips64/kstat_cp.h    |  8 ++---
>  .../unix/sysv/linux/sparc/sparc64/kstat_cp.h  |  4 +--
>  4 files changed, 40 insertions(+), 33 deletions(-)
> 
> diff --git a/sysdeps/unix/sysv/linux/fstatat.c b/sysdeps/unix/sysv/linux/fstatat.c
> index c7fcfaf277..78fad51961 100644
> --- a/sysdeps/unix/sysv/linux/fstatat.c
> +++ b/sysdeps/unix/sysv/linux/fstatat.c
> @@ -26,22 +26,24 @@
>  int
>  __fstatat (int fd, const char *file, struct stat *buf, int flag)
>  {
> +  int r;
> +
>  # if STAT_IS_KERNEL_STAT
>    /* New kABIs which uses generic pre 64-bit time Linux ABI, e.g.
>       csky, nios2  */
> -  int r = INLINE_SYSCALL_CALL (fstatat64, fd, file, buf, flag);
> -  if (r == 0 && (buf->__st_ino_pad != 0
> -		 || buf->__st_size_pad != 0
> -		 || buf->__st_blocks_pad != 0))
> +  r = INTERNAL_SYSCALL_CALL (fstatat64, fd, file, buf, flag);
> +  if (! INTERNAL_SYSCALL_ERROR_P (r)
> +      && (buf->__st_ino_pad != 0
> +	  || buf->__st_size_pad != 0
> +	  || buf->__st_blocks_pad != 0))
>      return INLINE_SYSCALL_ERROR_RETURN_VALUE (EOVERFLOW);
> -  return r;
>  # else
>  #  ifdef __NR_fstatat64
>    /* Old KABIs with old non-LFS support, e.g. arm, i386, hppa, m68k, mips32,
>       microblaze, s390, sh, powerpc, and sparc.  */
>    struct stat64 st64;
> -  int r = INLINE_SYSCALL_CALL (fstatat64, fd, file, &st64, flag);
> -  if (r == 0)
> +  r = INTERNAL_SYSCALL_CALL (fstatat64, fd, file, &st64, flag);
> +  if (! INTERNAL_SYSCALL_ERROR_P (r))
>      {
>        if (! in_ino_t_range (st64.st_ino)
>  	  || ! in_off_t_range (st64.st_size)
> @@ -67,15 +69,21 @@ __fstatat (int fd, const char *file, struct stat *buf, int flag)
>        buf->st_mtim.tv_nsec = st64.st_mtim.tv_nsec;
>        buf->st_ctim.tv_sec = st64.st_ctim.tv_sec;
>        buf->st_ctim.tv_nsec = st64.st_ctim.tv_nsec;
> +
> +      return 0;
>      }
> -  return r;
>  #  else
>    /* 64-bit kabi outlier, e.g. mips64 and mips64-n32.  */
>    struct kernel_stat kst;
> -  int r = INLINE_SYSCALL_CALL (newfstatat, fd, file, &kst, flag);
> -  return r ?: __cp_kstat_stat (&kst, buf);
> +  r = INTERNAL_SYSCALL_CALL (newfstatat, fd, file, &kst, flag);
> +  if (! INTERNAL_SYSCALL_ERROR_P (r))
> +    r = __cp_kstat_stat (&kst, buf);
>  #  endif /* __nr_fstatat64  */
>  # endif /* STAT_IS_KERNEL_STAT  */
> +
> +  return INTERNAL_SYSCALL_ERROR_P (r)
> +	 ? INLINE_SYSCALL_ERROR_RETURN_VALUE (-r)
> +	 : 0;
>  }
>  
>  weak_alias (__fstatat, fstatat)
> diff --git a/sysdeps/unix/sysv/linux/fstatat64.c b/sysdeps/unix/sysv/linux/fstatat64.c
> index ae8fc101c5..f9b603ce5a 100644
> --- a/sysdeps/unix/sysv/linux/fstatat64.c
> +++ b/sysdeps/unix/sysv/linux/fstatat64.c
> @@ -39,31 +39,32 @@ __fstatat64_time64 (int fd, const char *file, struct __stat64_t64 *buf,
>    /* 32-bit kABI with default 64-bit time_t, e.g. arc, riscv32.   Also
>       64-bit time_t support is done through statx syscall.  */
>    struct statx tmp;
> -  r = INLINE_SYSCALL_CALL (statx, fd, file, AT_NO_AUTOMOUNT | flag,
> -			   STATX_BASIC_STATS, &tmp);
> -  if (r == 0 || errno != ENOSYS)
> +  r = INTERNAL_SYSCALL_CALL (statx, fd, file, AT_NO_AUTOMOUNT | flag,
> +			     STATX_BASIC_STATS, &tmp);
> +  if (! INTERNAL_SYSCALL_ERROR_P (r))
>      {
> -      if (r == 0)
> -	__cp_stat64_t64_statx (buf, &tmp);
> +      __cp_stat64_t64_statx (buf, &tmp);
>        return r;
>      }
> +  if (-r != ENOSYS)
> +    return INLINE_SYSCALL_ERROR_RETURN_VALUE (-r);
>  #endif
>  
>  #if XSTAT_IS_XSTAT64
>  # ifdef __NR_newfstatat
>    /* 64-bit kABI, e.g. aarch64, ia64, powerpc64*, s390x, riscv64, and
>       x86_64.  */
> -  r = INLINE_SYSCALL_CALL (newfstatat, fd, file, buf, flag);
> +  r = INTERNAL_SYSCALL_CALL (newfstatat, fd, file, buf, flag);
>  # elif defined __NR_fstatat64
>  #  if STAT64_IS_KERNEL_STAT64
>    /* 64-bit kABI outlier, e.g. alpha  */
> -  r = INLINE_SYSCALL_CALL (fstatat64, fd, file, buf, flag);
> +  r = INTERNAL_SYSCALL_CALL (fstatat64, fd, file, buf, flag);
>  #  else
>    /* 64-bit kABI outlier, e.g. sparc64.  */
>    struct kernel_stat64 kst64;
> -  r = INLINE_SYSCALL_CALL (fstatat64, fd, file, &kst64, flag);
> -  if (r == 0)
> -    r = __cp_stat64_kstat64 (buf, &kst64);
> +  r = INTERNAL_SYSCALL_CALL (fstatat64, fd, file, &kst64, flag);
> +  if (! INTERNAL_SYSCALL_ERROR_P (r))
> +    __cp_stat64_kstat64 (buf, &kst64);
>  #  endif
>  # endif
>  #else
> @@ -72,8 +73,8 @@ __fstatat64_time64 (int fd, const char *file, struct __stat64_t64 *buf,
>       e.g. arm, csky, i386, hppa, m68k, microblaze, nios2, sh, powerpc32,
>       and sparc32.  */
>    struct stat64 st64;
> -  r = INLINE_SYSCALL_CALL (fstatat64, fd, file, &st64, flag);
> -  if (r == 0)
> +  r = INTERNAL_SYSCALL_CALL (fstatat64, fd, file, &st64, flag);
> +  if (! INTERNAL_SYSCALL_ERROR_P (r))
>      {
>        /* Clear both pad and reserved fields.  */
>        memset (buf, 0, sizeof (*buf));
> @@ -95,13 +96,15 @@ __fstatat64_time64 (int fd, const char *file, struct __stat64_t64 *buf,
>  # else
>    /* 64-bit kabi outlier, e.g. mips64 and mips64-n32.  */
>    struct kernel_stat kst;
> -  r = INLINE_SYSCALL_CALL (newfstatat, fd, file, &kst, flag);
> +  r = INTERNAL_SYSCALL_CALL (newfstatat, fd, file, &kst, flag);
>    if (r == 0)
> -    r =  __cp_kstat_stat64_t64 (&kst, buf);
> +    __cp_kstat_stat64_t64 (&kst, buf);
>  # endif
>  #endif
>  
> -  return r;
> +  return INTERNAL_SYSCALL_ERROR_P (r)
> +	 ? INLINE_SYSCALL_ERROR_RETURN_VALUE (-r)
> +	 : 0;
>  }
>  #if __TIMESIZE != 64
>  hidden_def (__fstatat64_time64)
> diff --git a/sysdeps/unix/sysv/linux/mips/mips64/kstat_cp.h b/sysdeps/unix/sysv/linux/mips/mips64/kstat_cp.h
> index 1805d4b85f..71fe39fdd0 100644
> --- a/sysdeps/unix/sysv/linux/mips/mips64/kstat_cp.h
> +++ b/sysdeps/unix/sysv/linux/mips/mips64/kstat_cp.h
> @@ -19,13 +19,13 @@
>  #include <sys/stat.h>
>  #include <kernel_stat.h>
>  
> -static inline int
> +static inline long int
>  __cp_kstat_stat (const struct kernel_stat *kst, struct stat *st)
>  {
>    if (! in_ino_t_range (kst->st_ino)
>        || ! in_off_t_range (kst->st_size)
>        || ! in_blkcnt_t_range (kst->st_blocks))
> -    return INLINE_SYSCALL_ERROR_RETURN_VALUE (EOVERFLOW);
> +    return -EOVERFLOW;
>  
>    st->st_dev = kst->st_dev;
>    memset (&st->st_pad1, 0, sizeof (st->st_pad1));
> @@ -51,7 +51,7 @@ __cp_kstat_stat (const struct kernel_stat *kst, struct stat *st)
>    return 0;
>  }
>  
> -static inline int
> +static inline void
>  __cp_kstat_stat64_t64 (const struct kernel_stat *kst, struct __stat64_t64 *st)
>  {
>    st->st_dev = kst->st_dev;
> @@ -70,6 +70,4 @@ __cp_kstat_stat64_t64 (const struct kernel_stat *kst, struct __stat64_t64 *st)
>    st->st_mtim.tv_nsec = kst->st_mtime_nsec;
>    st->st_ctim.tv_sec = kst->st_ctime_sec;
>    st->st_ctim.tv_nsec = kst->st_ctime_nsec;
> -
> -  return 0;
>  }
> diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/kstat_cp.h b/sysdeps/unix/sysv/linux/sparc/sparc64/kstat_cp.h
> index 0599b6a49e..d3f2841ade 100644
> --- a/sysdeps/unix/sysv/linux/sparc/sparc64/kstat_cp.h
> +++ b/sysdeps/unix/sysv/linux/sparc/sparc64/kstat_cp.h
> @@ -18,7 +18,7 @@
>  
>  #include <errno.h>
>  
> -static inline int
> +static inline void
>  __cp_stat64_kstat64 (struct stat64 *st64, const struct kernel_stat64 *kst64)
>  {
>    st64->st_dev = kst64->st_dev;
> @@ -41,6 +41,4 @@ __cp_stat64_kstat64 (struct stat64 *st64, const struct kernel_stat64 *kst64)
>    st64->st_ctim.tv_nsec = kst64->st_ctime_nsec;
>    st64->__glibc_reserved4 = 0;
>    st64->__glibc_reserved5 = 0;
> -
> -  return 0;
>  }
> 


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