From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: libc-alpha@sourceware.org
Subject: Re: [PATCHv2] alpha: Remove anonymous union in struct stat [BZ #27042]
Date: Thu, 10 Dec 2020 18:18:06 -0300 [thread overview]
Message-ID: <b43f05e7-36c1-8ca0-8358-d7b905c44504@linaro.org> (raw)
In-Reply-To: <20201210011945.2076794-1-mattst88@gmail.com>
On 09/12/2020 22:19, Matt Turner via Libc-alpha wrote:
> This is clever, but it confuses downstream detection in at least zstd
> and GNOME's glib. zstd has preprocessor tests for the 'st_mtime' macro,
> which is not provided by the path using the anonymous union; glib checks
> for the presence of 'st_mtimensec' in struct stat but then tries to
> access that field in struct statx (which might be a bug on its own).
> ---
> The macros affect the definitions in kernel_stat.h, so rename them. Not
> thrilled.
LGTM, thanks.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
>
> .../unix/sysv/linux/alpha/bits/struct_stat.h | 81 ++++++++++---------
> sysdeps/unix/sysv/linux/alpha/kernel_stat.h | 24 +++---
> sysdeps/unix/sysv/linux/alpha/xstatconv.c | 24 +++---
> 3 files changed, 66 insertions(+), 63 deletions(-)
>
> diff --git a/sysdeps/unix/sysv/linux/alpha/bits/struct_stat.h b/sysdeps/unix/sysv/linux/alpha/bits/struct_stat.h
> index 1c9b4248b8..d2aae9fdd7 100644
> --- a/sysdeps/unix/sysv/linux/alpha/bits/struct_stat.h
> +++ b/sysdeps/unix/sysv/linux/alpha/bits/struct_stat.h
> @@ -23,37 +23,6 @@
> #ifndef _BITS_STRUCT_STAT_H
> #define _BITS_STRUCT_STAT_H 1
>
> -/* Nanosecond resolution timestamps are stored in a format equivalent to
> - 'struct timespec'. This is the type used whenever possible but the
> - Unix namespace rules do not allow the identifier 'timespec' to appear
> - in the <sys/stat.h> header. Therefore we have to handle the use of
> - this header in strictly standard-compliant sources special.
> -
> - Use neat tidy anonymous unions and structures when possible. */
> -
> -#ifdef __USE_XOPEN2K8
> -# if __GNUC_PREREQ(3,3)
> -# define __ST_TIME(X) \
> - __extension__ union { \
> - struct timespec st_##X##tim; \
> - struct { \
> - __time_t st_##X##time; \
> - unsigned long st_##X##timensec; \
> - }; \
> - }
> -# else
> -# define __ST_TIME(X) struct timespec st_##X##tim
> -# define st_atime st_atim.tv_sec
> -# define st_mtime st_mtim.tv_sec
> -# define st_ctime st_ctim.tv_sec
> -# endif
> -#else
> -# define __ST_TIME(X) \
> - __time_t st_##X##time; \
> - unsigned long st_##X##timensec
> -#endif
> -
> -
> struct stat
> {
> __dev_t st_dev; /* Device. */
> @@ -77,9 +46,27 @@ struct stat
> __blksize_t st_blksize; /* Optimal block size for I/O. */
> __nlink_t st_nlink; /* Link count. */
> int __pad2; /* Real padding. */
> - __ST_TIME(a); /* Time of last access. */
> - __ST_TIME(m); /* Time of last modification. */
> - __ST_TIME(c); /* Time of last status change. */
> +#ifdef __USE_XOPEN2K8
> + /* Nanosecond resolution timestamps are stored in a format
> + equivalent to 'struct timespec'. This is the type used
> + whenever possible but the Unix namespace rules do not allow the
> + identifier 'timespec' to appear in the <sys/stat.h> header.
> + Therefore we have to handle the use of this header in strictly
> + standard-compliant sources special. */
> + struct timespec st_atim; /* Time of last access. */
> + struct timespec st_mtim; /* Time of last modification. */
> + struct timespec st_ctim; /* Time of last status change. */
> +# define st_atime st_atim.tv_sec /* Backward compatibility. */
> +# define st_mtime st_mtim.tv_sec
> +# define st_ctime st_ctim.tv_sec
> +#else
> + __time_t st_atime; /* Time of last access. */
> + unsigned long int st_atimensec; /* Nscecs of last access. */
> + __time_t st_mtime; /* Time of last modification. */
> + unsigned long int st_mtimensec; /* Nsecs of last modification. */
> + __time_t st_ctime; /* Time of last status change. */
> + unsigned long int st_ctimensec; /* Nsecs of last status change. */
> +#endif
> long __glibc_reserved[3];
> };
>
> @@ -98,15 +85,31 @@ struct stat64
> __blksize_t st_blksize; /* Optimal block size for I/O. */
> __nlink_t st_nlink; /* Link count. */
> int __pad0; /* Real padding. */
> - __ST_TIME(a); /* Time of last access. */
> - __ST_TIME(m); /* Time of last modification. */
> - __ST_TIME(c); /* Time of last status change. */
> +#ifdef __USE_XOPEN2K8
> + /* Nanosecond resolution timestamps are stored in a format
> + equivalent to 'struct timespec'. This is the type used
> + whenever possible but the Unix namespace rules do not allow the
> + identifier 'timespec' to appear in the <sys/stat.h> header.
> + Therefore we have to handle the use of this header in strictly
> + standard-compliant sources special. */
> + struct timespec st_atim; /* Time of last access. */
> + struct timespec st_mtim; /* Time of last modification. */
> + struct timespec st_ctim; /* Time of last status change. */
> +# define st_atime st_atim.tv_sec /* Backward compatibility. */
> +# define st_mtime st_mtim.tv_sec
> +# define st_ctime st_ctim.tv_sec
> +#else
> + __time_t st_atime; /* Time of last access. */
> + unsigned long int st_atimensec; /* Nscecs of last access. */
> + __time_t st_mtime; /* Time of last modification. */
> + unsigned long int st_mtimensec; /* Nsecs of last modification. */
> + __time_t st_ctime; /* Time of last status change. */
> + unsigned long int st_ctimensec; /* Nsecs of last status change. */
> +#endif
> long __glibc_reserved[3];
> };
> #endif
>
> -#undef __ST_TIME
> -
> /* Tell code we have these members. */
> #define _STATBUF_ST_BLKSIZE
> #define _STATBUF_ST_RDEV
> diff --git a/sysdeps/unix/sysv/linux/alpha/kernel_stat.h b/sysdeps/unix/sysv/linux/alpha/kernel_stat.h
> index ff69045f8f..a292920969 100644
> --- a/sysdeps/unix/sysv/linux/alpha/kernel_stat.h
> +++ b/sysdeps/unix/sysv/linux/alpha/kernel_stat.h
> @@ -9,9 +9,9 @@ struct kernel_stat
> unsigned int st_gid;
> unsigned int st_rdev;
> long int st_size;
> - unsigned long int st_atime;
> - unsigned long int st_mtime;
> - unsigned long int st_ctime;
> + unsigned long int st_atime_sec;
> + unsigned long int st_mtime_sec;
> + unsigned long int st_ctime_sec;
> unsigned int st_blksize;
> int st_blocks;
> unsigned int st_flags;
> @@ -34,11 +34,11 @@ struct kernel_stat64
> unsigned int st_nlink;
> unsigned int __pad0;
>
> - unsigned long st_atime;
> + unsigned long st_atime_sec;
> unsigned long st_atimensec;
> - unsigned long st_mtime;
> + unsigned long st_mtime_sec;
> unsigned long st_mtimensec;
> - unsigned long st_ctime;
> + unsigned long st_ctime_sec;
> unsigned long st_ctimensec;
> long __glibc_reserved[3];
> };
> @@ -54,9 +54,9 @@ struct glibc2_stat
> __gid_t st_gid;
> __dev_t st_rdev;
> __off_t st_size;
> - __time_t st_atime;
> - __time_t st_mtime;
> - __time_t st_ctime;
> + __time_t st_atime_sec;
> + __time_t st_mtime_sec;
> + __time_t st_ctime_sec;
> unsigned int st_blksize;
> int st_blocks;
> unsigned int st_flags;
> @@ -74,9 +74,9 @@ struct glibc21_stat
> __gid_t st_gid;
> __dev_t st_rdev;
> __off_t st_size;
> - __time_t st_atime;
> - __time_t st_mtime;
> - __time_t st_ctime;
> + __time_t st_atime_sec;
> + __time_t st_mtime_sec;
> + __time_t st_ctime_sec;
> __blkcnt64_t st_blocks;
> __blksize_t st_blksize;
> unsigned int st_flags;
> diff --git a/sysdeps/unix/sysv/linux/alpha/xstatconv.c b/sysdeps/unix/sysv/linux/alpha/xstatconv.c
> index f716a10f34..43224a7f25 100644
> --- a/sysdeps/unix/sysv/linux/alpha/xstatconv.c
> +++ b/sysdeps/unix/sysv/linux/alpha/xstatconv.c
> @@ -44,9 +44,9 @@ __xstat_conv (int vers, struct kernel_stat *kbuf, void *ubuf)
> buf->st_gid = kbuf->st_gid;
> buf->st_rdev = kbuf->st_rdev;
> buf->st_size = kbuf->st_size;
> - buf->st_atime = kbuf->st_atime;
> - buf->st_mtime = kbuf->st_mtime;
> - buf->st_ctime = kbuf->st_ctime;
> + buf->st_atime_sec = kbuf->st_atime_sec;
> + buf->st_mtime_sec = kbuf->st_mtime_sec;
> + buf->st_ctime_sec = kbuf->st_ctime_sec;
> buf->st_blksize = kbuf->st_blksize;
> buf->st_blocks = kbuf->st_blocks;
> buf->st_flags = kbuf->st_flags;
> @@ -66,9 +66,9 @@ __xstat_conv (int vers, struct kernel_stat *kbuf, void *ubuf)
> buf->st_gid = kbuf->st_gid;
> buf->st_rdev = kbuf->st_rdev;
> buf->st_size = kbuf->st_size;
> - buf->st_atime = kbuf->st_atime;
> - buf->st_mtime = kbuf->st_mtime;
> - buf->st_ctime = kbuf->st_ctime;
> + buf->st_atime_sec = kbuf->st_atime_sec;
> + buf->st_mtime_sec = kbuf->st_mtime_sec;
> + buf->st_ctime_sec = kbuf->st_ctime_sec;
> buf->st_blocks = kbuf->st_blocks;
> buf->st_blksize = kbuf->st_blksize;
> buf->st_flags = kbuf->st_flags;
> @@ -98,12 +98,12 @@ __xstat_conv (int vers, struct kernel_stat *kbuf, void *ubuf)
> buf->st_nlink = kbuf->st_nlink;
> buf->__pad0 = 0;
>
> - buf->st_atime = kbuf->st_atime;
> - buf->st_atimensec = 0;
> - buf->st_mtime = kbuf->st_mtime;
> - buf->st_mtimensec = 0;
> - buf->st_ctime = kbuf->st_ctime;
> - buf->st_ctimensec = 0;
> + buf->st_atim.tv_sec = kbuf->st_atime_sec;
> + buf->st_atim.tv_nsec = 0;
> + buf->st_mtim.tv_sec = kbuf->st_mtime_sec;
> + buf->st_mtim.tv_nsec = 0;
> + buf->st_ctim.tv_sec = kbuf->st_ctime_sec;
> + buf->st_ctim.tv_nsec = 0;
>
> buf->__glibc_reserved[0] = 0;
> buf->__glibc_reserved[1] = 0;
>
next prev parent reply other threads:[~2020-12-10 21:18 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-09 16:20 [PATCH] " Matt Turner
2020-12-09 17:11 ` Florian Weimer
2020-12-10 1:25 ` Matt Turner
2020-12-10 1:19 ` [PATCHv2] " Matt Turner
2020-12-10 21:18 ` Adhemerval Zanella [this message]
2020-12-15 16:43 ` Matt Turner
2020-12-15 16:48 ` Adhemerval Zanella
2020-12-15 16:56 ` Florian Weimer
2020-12-17 18:18 ` Matt Turner
2020-12-17 19:10 ` Adhemerval Zanella
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