From: Sergey Bugaev <bugaevc@gmail.com>
To: libc-alpha@sourceware.org
Cc: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Subject: [PATCH v4 2/6] support: Add support_fcntl_support_ofd_locks ()
Date: Sun, 30 Jul 2023 22:25:57 +0300 [thread overview]
Message-ID: <20230730192605.2423480-3-bugaevc@gmail.com> (raw)
In-Reply-To: <20230730192605.2423480-1-bugaevc@gmail.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
---
support/Makefile | 1 +
support/support.h | 3 ++
support/support_fcntl_support_ofd_locks.c | 44 +++++++++++++++++++++++
3 files changed, 48 insertions(+)
create mode 100644 support/support_fcntl_support_ofd_locks.c
diff --git a/support/Makefile b/support/Makefile
index 917a858b..ab5d46b8 100644
--- a/support/Makefile
+++ b/support/Makefile
@@ -58,6 +58,7 @@ libsupport-routines = \
support_descriptors \
support_enter_mount_namespace \
support_enter_network_namespace \
+ support_fcntl_support_ofd_locks \
support_format_address_family \
support_format_addrinfo \
support_format_dns_packet \
diff --git a/support/support.h b/support/support.h
index b7f76bf0..e20d2ce7 100644
--- a/support/support.h
+++ b/support/support.h
@@ -178,6 +178,9 @@ static __inline bool support_itimer_support_time64 (void)
#endif
}
+/* Return true if the kernel/file supports open file description locks. */
+extern bool support_fcntl_support_ofd_locks (int fd);
+
/* Return true if stat supports nanoseconds resolution. PATH is used
for tests and its ctime may change. */
extern bool support_stat_nanoseconds (const char *path);
diff --git a/support/support_fcntl_support_ofd_locks.c b/support/support_fcntl_support_ofd_locks.c
new file mode 100644
index 00000000..fb197a70
--- /dev/null
+++ b/support/support_fcntl_support_ofd_locks.c
@@ -0,0 +1,44 @@
+/* Return whether the kernel/file supports OFD locks.
+ Copyright (C) 2023 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <support/support.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <string.h>
+
+bool
+support_fcntl_support_ofd_locks (int fd)
+{
+#ifdef F_OFD_GETLK
+ int res;
+ struct flock flock;
+ memset (&flock, 0, sizeof (flock));
+
+ flock.l_type = F_WRLCK;
+ flock.l_whence = SEEK_SET;
+ flock.l_start = 0;
+ flock.l_len = INT32_MAX;
+ flock.l_pid = 0;
+
+ res = fcntl (fd, F_OFD_GETLK, &flock);
+ return res != -1 || errno != EINVAL;
+#else
+ (void) fd;
+ return false;
+#endif
+}
--
2.41.0
next prev parent reply other threads:[~2023-07-30 19:26 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-30 19:25 [PATCH v4 0/6] fcntl fortification Sergey Bugaev
2023-07-30 19:25 ` [PATCH v4 1/6] Fix calling fcntl64 (fd, F_SETLK, &flock64) Sergey Bugaev
2023-07-31 17:50 ` Adhemerval Zanella Netto
2023-08-08 18:40 ` Sergey Bugaev
2023-07-30 19:25 ` Sergey Bugaev [this message]
2023-07-30 19:25 ` [PATCH v4 3/6] cdefs.h: Define __glibc_warn_system_headers_{begin,end} Sergey Bugaev
2023-07-30 19:25 ` [PATCH v4 4/6] cdefs.h: Enable __errordecl & __warnattr for Clang 14+ Sergey Bugaev
2023-08-02 17:23 ` Adhemerval Zanella Netto
2023-07-30 19:26 ` [PATCH v4 5/6] io: Add FORTIFY_SOURCE check for fcntl arguments Sergey Bugaev
2023-07-30 19:54 ` Sergey Bugaev
2023-08-02 19:46 ` Adhemerval Zanella Netto
2023-07-30 19:26 ` [PATCH v4 6/6] io: Also verify 2-arg fctnl calls at runtime Sergey Bugaev
2023-08-08 18:29 ` Adhemerval Zanella Netto
2023-07-31 14:40 ` [PATCH v4 0/6] fcntl fortification Zack Weinberg
2023-07-31 17:25 ` Adhemerval Zanella Netto
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