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linux: Consolidate xstat{64}

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The LFS support is implemented on xstat64.c, instead of xstat.c for
64-bit architectures.  The xstat.c implements the non-LFS it is
no-op for !XSTAT_IS_XSTAT64.

The generic non-LFS implementation handle two cases:

  1. New kABIs which uses generic pre 64-bit time Linux ABI (csky and
     nios): it issues __NR_fstat64 plus handle the overflow on st_ino,
     st_size, or st_blocks.  It only handles _STAT_VER_KERNEL.

  2. Old KABIs with old non-LFS support (arm, i386, hppa, m68k,
     microblaze, s390, sh, powerpc, and sparc32).  For _STAT_VER_KERNEL
     it issues __NR_stat, otherwise it issues __NR_stat64 and convert
     to non-LFS stat struct handling possible overflows on st_ino,
     st_size, or st_blocks.

Also the non-LFS mips is an outlier and it has its own implementation
since _STAT_VER_LINUX requires a different conversion function (it uses
the kernel_stat as the syscall argument since its exported ABI is
different than the kernel one for both non-LFS and LFS implementation).

The generic LFS implementation handles multiple cases:

  1. XSTAT_IS_XSTAT64 being 1:

    1.1. Old 64-bit kABI (ia64, powerpc64*, s390x, x86_64): it
         issues __NR_stat for _STAT_VER_KERNEL or _STAT_VER_LINUX.

    1.2. Old 64-bit kABI with defines __NR_stat64 instead of __NR_stat
	 (sparc64): it issues __NR_stat for _STAT_VER_KERNEL or
	 __NR_stat64 and convert to struct stat64.

    1.3. New kABIs which uses generic 64-bit Linux ABI (aarch64 and
         riscv64): it issues __NR_newfstatat and only for
         _STAT_VER_KERNEL.

    1.4. New 32-bit kABIs with only 64-bit time_t support (arc and
	 riscv32): it issues __NR_statx and covert to struct stat64.

  2. Old ABIs with XSTAT_IS_XSTAT64 being 0:

    2.1. New kABIs which uses generic pre 64-bit time Linux ABI (csky
	 and nios2): it issues __NR_fstatat64 for _STAT_VER_KERNEL.

    2.2. Old kABIs with old non-LFS support (arm, i386, hppa, m68k,
	 microblaze, s390, sh, mips32, powerpc32, and sparc32): it
	 issues __NR_stat64.

Also, two special cases requires specific LFS implementations:

  1. alpha: it requires to handle _STAT_VER_KERNEL64 to call __NR_stat64
     or use the kernel_stat with __NR_stat otherwise.

  2. mips64: as for non-LFS implementation its ABIs differ from glibc
     exported one, which requires an specific conversion function to
     handle the kernel_stat.

Checked with a build for all affected ABIs. I also checked on x86_64,
i686, powerpc, powerpc64le, sparcv9, sparc64, s390, and s390x.

Reviewed-by: Lukasz Majewski <lukma@denx.de>
This commit is contained in:
Adhemerval Zanella
2020-07-13 09:13:12 -03:00
parent 0b1c222cd0
commit 71aadfb8ae
20 changed files with 191 additions and 329 deletions
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58
sysdeps/unix/sysv/linux/xstat.c
View File

@ -16,44 +16,46 @@
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
/* Ho hum, if xstat == xstat64 we must get rid of the prototype or gcc
will complain since they don't strictly match. */
#define __xstat64 __xstat64_disable
#include <errno.h>
#include <stddef.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <kernel_stat.h>
#include <sysdep.h>
#include <sys/syscall.h>
#include <xstatconv.h>
#if !XSTAT_IS_XSTAT64
# include <xstatconv.h>
# include <xstatover.h>
/* Get information about the file NAME in BUF. */
int
__xstat (int vers, const char *name, struct stat *buf)
{
if (vers == _STAT_VER_KERNEL)
return INLINE_SYSCALL (stat, 2, name, buf);
switch (vers)
{
case _STAT_VER_KERNEL:
{
# 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, AT_FDCWD, name, buf, 0);
return r ?: stat_overflow (buf);
# else
/* Old kABIs with old non-LFS support, e.g. arm, i386, hppa, m68k,
microblaze, s390, sh, powerpc, and sparc32. */
return INLINE_SYSCALL_CALL (stat, name, buf);
# endif
}
#if STAT_IS_KERNEL_STAT
return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
#else
struct kernel_stat kbuf;
int result;
result = INLINE_SYSCALL (stat, 2, name, &kbuf);
if (result == 0)
result = __xstat_conv (vers, &kbuf, buf);
return result;
default:
{
# if STAT_IS_KERNEL_STAT
return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
# else
struct stat64 buf64;
int r = INLINE_SYSCALL_CALL (stat64, name, &buf64);
return r ?: __xstat32_conv (vers, &buf64, buf);
#endif
}
}
}
hidden_def (__xstat)
weak_alias (__xstat, _xstat);
#if XSTAT_IS_XSTAT64
#undef __xstat64
strong_alias (__xstat, __xstat64);
hidden_ver (__xstat, __xstat64)
#endif
#endif /* XSTAT_IS_XSTAT64 */