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Message-ID: <ZvrIKL3cREoRHIQd@x1>
Date: Mon, 30 Sep 2024 12:47:52 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: linux-kernel@...r.kernel.org
Cc: Adrian Hunter <adrian.hunter@...el.com>,
Aleksa Sarai <cyphar@...har.com>,
Christian Brauner <brauner@...nel.org>,
Ian Rogers <irogers@...gle.com>, Jiri Olsa <jolsa@...nel.org>,
Kan Liang <kan.liang@...ux.intel.com>,
Namhyung Kim <namhyung@...nel.org>, Tejun Heo <tj@...nel.org>
Subject: [PATCH 1/1 fyi] tools include UAPI: Sync linux/fcntl.h copy with the
kernel sources
Picking the changes from:
4356d575ef0f39a3 ("fhandle: expose u64 mount id to name_to_handle_at(2)")
b4fef22c2fb97fa2 ("uapi: explain how per-syscall AT_* flags should be allocated")
820a185896b77814 ("fcntl: add F_CREATED_QUERY")
It just moves AT_REMOVEDIR around, and adds a bunch more AT_ for
renameat2() and name_to_handle_at(). We need to improve this situation,
as not all AT_ defines are applicable to all fs flags...
This adds support for those new AT_ defines, addressing this build
warning:
diff -u tools/perf/trace/beauty/include/uapi/sound/asound.h include/uapi/sound/asound.h
Cc: Adrian Hunter <adrian.hunter@...el.com>
Cc: Aleksa Sarai <cyphar@...har.com>
Cc: Christian Brauner <brauner@...nel.org>
Cc: Ian Rogers <irogers@...gle.com>
Cc: Jiri Olsa <jolsa@...nel.org>
Cc: Kan Liang <kan.liang@...ux.intel.com>
Cc: Namhyung Kim <namhyung@...nel.org>
Cc: Tejun Heo <tj@...nel.org>
Link: https://lore.kernel.org/lkml/
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
tools/perf/trace/beauty/fs_at_flags.sh | 5 ++
.../trace/beauty/include/uapi/linux/fcntl.h | 84 +++++++++++++------
2 files changed, 65 insertions(+), 24 deletions(-)
diff --git a/tools/perf/trace/beauty/fs_at_flags.sh b/tools/perf/trace/beauty/fs_at_flags.sh
index 456f59addf741062..e3f13f96a27c227c 100755
--- a/tools/perf/trace/beauty/fs_at_flags.sh
+++ b/tools/perf/trace/beauty/fs_at_flags.sh
@@ -13,9 +13,14 @@ printf "static const char *fs_at_flags[] = {\n"
regex='^[[:space:]]*#[[:space:]]*define[[:space:]]+AT_([^_]+[[:alnum:]_]+)[[:space:]]+(0x[[:xdigit:]]+)[[:space:]]*.*'
# AT_EACCESS is only meaningful to faccessat, so we will special case it there...
# AT_STATX_SYNC_TYPE is not a bit, its a mask of AT_STATX_SYNC_AS_STAT, AT_STATX_FORCE_SYNC and AT_STATX_DONT_SYNC
+# AT_HANDLE_FID and AT_HANDLE_MNT_ID_UNIQUE are reusing values and are valid only for name_to_handle_at()
+# AT_RENAME_NOREPLACE reuses 0x1 and is valid only for renameat2()
grep -E $regex ${linux_fcntl} | \
grep -v AT_EACCESS | \
grep -v AT_STATX_SYNC_TYPE | \
+ grep -v AT_HANDLE_FID | \
+ grep -v AT_HANDLE_MNT_ID_UNIQUE | \
+ grep -v AT_RENAME_NOREPLACE | \
sed -r "s/$regex/\2 \1/g" | \
xargs printf "\t[ilog2(%s) + 1] = \"%s\",\n"
printf "};\n"
diff --git a/tools/perf/trace/beauty/include/uapi/linux/fcntl.h b/tools/perf/trace/beauty/include/uapi/linux/fcntl.h
index c0bcc185fa48f852..87e2dec79fea4ef2 100644
--- a/tools/perf/trace/beauty/include/uapi/linux/fcntl.h
+++ b/tools/perf/trace/beauty/include/uapi/linux/fcntl.h
@@ -16,6 +16,9 @@
#define F_DUPFD_QUERY (F_LINUX_SPECIFIC_BASE + 3)
+/* Was the file just created? */
+#define F_CREATED_QUERY (F_LINUX_SPECIFIC_BASE + 4)
+
/*
* Cancel a blocking posix lock; internal use only until we expose an
* asynchronous lock api to userspace:
@@ -87,37 +90,70 @@
#define DN_ATTRIB 0x00000020 /* File changed attibutes */
#define DN_MULTISHOT 0x80000000 /* Don't remove notifier */
+#define AT_FDCWD -100 /* Special value for dirfd used to
+ indicate openat should use the
+ current working directory. */
+
+
+/* Generic flags for the *at(2) family of syscalls. */
+
+/* Reserved for per-syscall flags 0xff. */
+#define AT_SYMLINK_NOFOLLOW 0x100 /* Do not follow symbolic
+ links. */
+/* Reserved for per-syscall flags 0x200 */
+#define AT_SYMLINK_FOLLOW 0x400 /* Follow symbolic links. */
+#define AT_NO_AUTOMOUNT 0x800 /* Suppress terminal automount
+ traversal. */
+#define AT_EMPTY_PATH 0x1000 /* Allow empty relative
+ pathname to operate on dirfd
+ directly. */
+/*
+ * These flags are currently statx(2)-specific, but they could be made generic
+ * in the future and so they should not be used for other per-syscall flags.
+ */
+#define AT_STATX_SYNC_TYPE 0x6000 /* Type of synchronisation required from statx() */
+#define AT_STATX_SYNC_AS_STAT 0x0000 /* - Do whatever stat() does */
+#define AT_STATX_FORCE_SYNC 0x2000 /* - Force the attributes to be sync'd with the server */
+#define AT_STATX_DONT_SYNC 0x4000 /* - Don't sync attributes with the server */
+
+#define AT_RECURSIVE 0x8000 /* Apply to the entire subtree */
+
/*
- * The constants AT_REMOVEDIR and AT_EACCESS have the same value. AT_EACCESS is
- * meaningful only to faccessat, while AT_REMOVEDIR is meaningful only to
- * unlinkat. The two functions do completely different things and therefore,
- * the flags can be allowed to overlap. For example, passing AT_REMOVEDIR to
- * faccessat would be undefined behavior and thus treating it equivalent to
- * AT_EACCESS is valid undefined behavior.
+ * Per-syscall flags for the *at(2) family of syscalls.
+ *
+ * These are flags that are so syscall-specific that a user passing these flags
+ * to the wrong syscall is so "clearly wrong" that we can safely call such
+ * usage "undefined behaviour".
+ *
+ * For example, the constants AT_REMOVEDIR and AT_EACCESS have the same value.
+ * AT_EACCESS is meaningful only to faccessat, while AT_REMOVEDIR is meaningful
+ * only to unlinkat. The two functions do completely different things and
+ * therefore, the flags can be allowed to overlap. For example, passing
+ * AT_REMOVEDIR to faccessat would be undefined behavior and thus treating it
+ * equivalent to AT_EACCESS is valid undefined behavior.
+ *
+ * Note for implementers: When picking a new per-syscall AT_* flag, try to
+ * reuse already existing flags first. This leaves us with as many unused bits
+ * as possible, so we can use them for generic bits in the future if necessary.
*/
-#define AT_FDCWD -100 /* Special value used to indicate
- openat should use the current
- working directory. */
-#define AT_SYMLINK_NOFOLLOW 0x100 /* Do not follow symbolic links. */
+
+/* Flags for renameat2(2) (must match legacy RENAME_* flags). */
+#define AT_RENAME_NOREPLACE 0x0001
+#define AT_RENAME_EXCHANGE 0x0002
+#define AT_RENAME_WHITEOUT 0x0004
+
+/* Flag for faccessat(2). */
#define AT_EACCESS 0x200 /* Test access permitted for
effective IDs, not real IDs. */
+/* Flag for unlinkat(2). */
#define AT_REMOVEDIR 0x200 /* Remove directory instead of
unlinking file. */
-#define AT_SYMLINK_FOLLOW 0x400 /* Follow symbolic links. */
-#define AT_NO_AUTOMOUNT 0x800 /* Suppress terminal automount traversal */
-#define AT_EMPTY_PATH 0x1000 /* Allow empty relative pathname */
-
-#define AT_STATX_SYNC_TYPE 0x6000 /* Type of synchronisation required from statx() */
-#define AT_STATX_SYNC_AS_STAT 0x0000 /* - Do whatever stat() does */
-#define AT_STATX_FORCE_SYNC 0x2000 /* - Force the attributes to be sync'd with the server */
-#define AT_STATX_DONT_SYNC 0x4000 /* - Don't sync attributes with the server */
-
-#define AT_RECURSIVE 0x8000 /* Apply to the entire subtree */
+/* Flags for name_to_handle_at(2). */
+#define AT_HANDLE_FID 0x200 /* File handle is needed to compare
+ object identity and may not be
+ usable with open_by_handle_at(2). */
+#define AT_HANDLE_MNT_ID_UNIQUE 0x001 /* Return the u64 unique mount ID. */
-/* Flags for name_to_handle_at(2). We reuse AT_ flag space to save bits... */
-#define AT_HANDLE_FID AT_REMOVEDIR /* file handle is needed to
- compare object identity and may not
- be usable to open_by_handle_at(2) */
#if defined(__KERNEL__)
#define AT_GETATTR_NOSEC 0x80000000
#endif
--
2.46.0
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