tools/nolibc: support nanoseconds in stat()

Keep backwards compatibility through unions.

The compatibility macros like

 #define st_atime st_atim.tv_sec

as documented in stat(3type) don't work for nolibc because it would
break with other stat-like structures that contain the field st_atime.

The stx_atime, stx_mtime, stx_ctime are in type of 'struct
statx_timestamp', which is incompatible with 'struct timespec', should
be converted explicitly.

    /* include/uapi/linux/stat.h */

    struct statx_timestamp {
    	__s64	tv_sec;
    	__u32	tv_nsec;
    	__s32	__reserved;
    };

    /* include/uapi/linux/time.h */
    struct timespec {
    	__kernel_old_time_t	tv_sec;		/* seconds */
    	long			tv_nsec;	/* nanoseconds */
    };

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/linux-riscv/3a3edd48-1ace-4c89-89e8-9c594dd1b3c9@t-8ch.de/
Co-authored-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
[wt: squashed Zhangjin & Thomas' patches into one to preserve "bisectability"]
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

2 files changed, 39 insertions, 33 deletions

diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h
index c688b410f9e4..7836d7e7760d 100644
--- a/tools/include/nolibc/sys.h
+++ b/tools/include/nolibc/sys.h
@@ -1161,23 +1161,26 @@ int sys_stat(const char *path, struct stat *buf)
 	long ret;
 
 	ret = sys_statx(AT_FDCWD, path, AT_NO_AUTOMOUNT, STATX_BASIC_STATS, &statx);
-	buf->st_dev     = ((statx.stx_dev_minor & 0xff)
-			  | (statx.stx_dev_major << 8)
-			  | ((statx.stx_dev_minor & ~0xff) << 12));
-	buf->st_ino     = statx.stx_ino;
-	buf->st_mode    = statx.stx_mode;
-	buf->st_nlink   = statx.stx_nlink;
-	buf->st_uid     = statx.stx_uid;
-	buf->st_gid     = statx.stx_gid;
-	buf->st_rdev    = ((statx.stx_rdev_minor & 0xff)
-			  | (statx.stx_rdev_major << 8)
-			  | ((statx.stx_rdev_minor & ~0xff) << 12));
-	buf->st_size    = statx.stx_size;
-	buf->st_blksize = statx.stx_blksize;
-	buf->st_blocks  = statx.stx_blocks;
-	buf->st_atime   = statx.stx_atime.tv_sec;
-	buf->st_mtime   = statx.stx_mtime.tv_sec;
-	buf->st_ctime   = statx.stx_ctime.tv_sec;
+	buf->st_dev          = ((statx.stx_dev_minor & 0xff)
+			       | (statx.stx_dev_major << 8)
+			       | ((statx.stx_dev_minor & ~0xff) << 12));
+	buf->st_ino          = statx.stx_ino;
+	buf->st_mode         = statx.stx_mode;
+	buf->st_nlink        = statx.stx_nlink;
+	buf->st_uid          = statx.stx_uid;
+	buf->st_gid          = statx.stx_gid;
+	buf->st_rdev         = ((statx.stx_rdev_minor & 0xff)
+			       | (statx.stx_rdev_major << 8)
+			       | ((statx.stx_rdev_minor & ~0xff) << 12));
+	buf->st_size         = statx.stx_size;
+	buf->st_blksize      = statx.stx_blksize;
+	buf->st_blocks       = statx.stx_blocks;
+	buf->st_atim.tv_sec  = statx.stx_atime.tv_sec;
+	buf->st_atim.tv_nsec = statx.stx_atime.tv_nsec;
+	buf->st_mtim.tv_sec  = statx.stx_mtime.tv_sec;
+	buf->st_mtim.tv_nsec = statx.stx_mtime.tv_nsec;
+	buf->st_ctim.tv_sec  = statx.stx_ctime.tv_sec;
+	buf->st_ctim.tv_nsec = statx.stx_ctime.tv_nsec;
 	return ret;
 }
 #else
@@ -1195,19 +1198,22 @@ int sys_stat(const char *path, struct stat *buf)
 #else
 #error Neither __NR_newfstatat nor __NR_stat defined, cannot implement sys_stat()
 #endif
-	buf->st_dev     = stat.st_dev;
-	buf->st_ino     = stat.st_ino;
-	buf->st_mode    = stat.st_mode;
-	buf->st_nlink   = stat.st_nlink;
-	buf->st_uid     = stat.st_uid;
-	buf->st_gid     = stat.st_gid;
-	buf->st_rdev    = stat.st_rdev;
-	buf->st_size    = stat.st_size;
-	buf->st_blksize = stat.st_blksize;
-	buf->st_blocks  = stat.st_blocks;
-	buf->st_atime   = stat.st_atime;
-	buf->st_mtime   = stat.st_mtime;
-	buf->st_ctime   = stat.st_ctime;
+	buf->st_dev          = stat.st_dev;
+	buf->st_ino          = stat.st_ino;
+	buf->st_mode         = stat.st_mode;
+	buf->st_nlink        = stat.st_nlink;
+	buf->st_uid          = stat.st_uid;
+	buf->st_gid          = stat.st_gid;
+	buf->st_rdev         = stat.st_rdev;
+	buf->st_size         = stat.st_size;
+	buf->st_blksize      = stat.st_blksize;
+	buf->st_blocks       = stat.st_blocks;
+	buf->st_atim.tv_sec  = stat.st_atime;
+	buf->st_atim.tv_nsec = stat.st_atime_nsec;
+	buf->st_mtim.tv_sec  = stat.st_mtime;
+	buf->st_mtim.tv_nsec = stat.st_mtime_nsec;
+	buf->st_ctim.tv_sec  = stat.st_ctime;
+	buf->st_ctim.tv_nsec = stat.st_ctime_nsec;
 	return ret;
 }
 #endif
diff --git a/tools/include/nolibc/types.h b/tools/include/nolibc/types.h
index 15b0baffd336..f96e28bff4ba 100644
--- a/tools/include/nolibc/types.h
+++ b/tools/include/nolibc/types.h
@@ -198,9 +198,9 @@ struct stat {
 	off_t     st_size;    /* total size, in bytes */
 	blksize_t st_blksize; /* blocksize for file system I/O */
 	blkcnt_t  st_blocks;  /* number of 512B blocks allocated */
-	time_t    st_atime;   /* time of last access */
-	time_t    st_mtime;   /* time of last modification */
-	time_t    st_ctime;   /* time of last status change */
+	union { time_t st_atime; struct timespec st_atim; }; /* time of last access */
+	union { time_t st_mtime; struct timespec st_mtim; }; /* time of last modification */
+	union { time_t st_ctime; struct timespec st_ctim; }; /* time of last status change */
 };
 
 /* WARNING, it only deals with the 4096 first majors and 256 first minors */