[PATCH v2 nolibc 36/53] tools/nolibc: support nanoseconds in stat()

Paul E. McKenney
2023-06-12T20:49:37Z

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>
---
tools/include/nolibc/sys.h | 66 +++++++++++---------
tools/include/nolibc/types.h | 6 +-
tools/testing/selftests/nolibc/nolibc-test.c | 23 +++++++
3 files changed, 62 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 */
diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
index 84a1b02eb6f9..0d76790ffb0d 100644
--- a/tools/testing/selftests/nolibc/nolibc-test.c
+++ b/tools/testing/selftests/nolibc/nolibc-test.c
@@ -501,6 +501,28 @@ static int test_fork(void)
}
}

+static int test_stat_timestamps(void)
+{
+ struct stat st;
+
+ if (sizeof(st.st_atim.tv_sec) != sizeof(st.st_atime))
+ return 1;
+
+ if (stat("/proc/self/", &st))
+ return 1;
+
+ if (st.st_atim.tv_sec != st.st_atime || st.st_atim.tv_nsec > 1000000000)
+ return 1;
+
+ if (st.st_mtim.tv_sec != st.st_mtime || st.st_mtim.tv_nsec > 1000000000)
+ return 1;
+
+ if (st.st_ctim.tv_sec != st.st_ctime || st.st_ctim.tv_nsec > 1000000000)
+ return 1;
+
+ return 0;
+}
+
/* Run syscall tests between IDs <min> and <max>.
* Return 0 on success, non-zero on failure.
*/
@@ -589,6 +611,7 @@ int run_syscall(int min, int max)
CASE_TEST(select_fault); EXPECT_SYSER(1, select(1, (void *)1, NULL, NULL, 0), -1, EFAULT); break;
CASE_TEST(stat_blah); EXPECT_SYSER(1, stat("/proc/self/blah", &stat_buf), -1, ENOENT); break;
CASE_TEST(stat_fault); EXPECT_SYSER(1, stat(NULL, &stat_buf), -1, EFAULT); break;
+ CASE_TEST(stat_timestamps); EXPECT_SYSZR(1, test_stat_timestamps()); break;
CASE_TEST(symlink_root); EXPECT_SYSER(1, symlink("/", "/"), -1, EEXIST); break;
CASE_TEST(unlink_root); EXPECT_SYSER(1, unlink("/"), -1, EISDIR); break;
CASE_TEST(unlink_blah); EXPECT_SYSER(1, unlink("/proc/self/blah"), -1, ENOENT); break;
--
2.40.1