Fallback using mlock is provided if the flags argument is zero.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
+2017-11-27 Florian Weimer <fweimer@redhat.com>
+
+ * sysdeps/unix/sysv/linux/mlock2.c: New file.
+ * sysdeps/unix/sysv/linux/tst-mlock2.c: Likewise.
+ * sysdeps/unix/sysv/linux/Makefile (routines): Add mlock2.
+ (tests): Add tst-mlock2.
+ * sysdeps/unix/sysv/linux/Versions (GLIBC_2.27): Export mlock2.
+ * sysdeps/unix/sysv/linux/kernel-features.h (__ASSUME_MLOCK2)
+ [__LINUX_KERNEL_VERSION >= 4.4]: Define.
+ * sysdeps/unix/sysv/linux/libc**.abilist: Update.
+ * manual/memory.texi (Page Lock Functions): Move @end deftypefun
+ for mlock. Document mlock2.
+
2017-11-27 Joseph Myers <joseph@codesourcery.com>
* sysdeps/ia64/Makeconfig (float64x-alias-fcts): New variable.
18661-3:2015. These are corresponding interfaces to those supported for
_Float128.
-* glibc now implements the memfd_create function on Linux.
+* glibc now implements the memfd_create and mlock2 functions on Linux.
Deprecated and removed features, and other changes affecting compatibility:
The kernel does not provide @code{mlock} capability.
@end table
+@end deftypefun
+
+@deftypefun int mlock2 (const void *@var{addr}, size_t @var{len}, unsigned int @var{flags})
+@standards{Linux, sys/mman.h}
+@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}}
+
+This function is similar to @code{mlock}. If @var{flags} is zero, a
+call to @code{mlock2} behaves exactly as the equivalent call to @code{mlock}.
+
+The @var{flags} argument must be a combination of zero or more of the
+following flags:
+
+@vtable @code
+@item MLOCK_ONFAULT
+@standards{Linux, sys/mman.h}
+Only those pages in the specified address range which are already in
+memory are locked immediately. Additional pages in the range are
+automatically locked in case of a page fault and allocation of memory.
+@end vtable
+
+Like @code{mlock}, @code{mlock2} returns zero on success and @code{-1}
+on failure, setting @code{errno} accordingly. Additional @code{errno}
+values defined for @code{mlock2} are:
+
+@table @code
+@item EINVAL
+The specified (non-zero) @var{flags} argument is not supported by this
+system.
+@end table
+@end deftypefun
You can lock @emph{all} a process' memory with @code{mlockall}. You
unlock memory with @code{munlock} or @code{munlockall}.
from the C code, e.g. the stack and automatic variables, and you
wouldn't know what address to tell @code{mlock}.
-@end deftypefun
-
@deftypefun int munlock (const void *@var{addr}, size_t @var{len})
@standards{POSIX.1b, sys/mman.h}
@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}}
setfsuid setfsgid epoll_pwait signalfd \
eventfd eventfd_read eventfd_write prlimit \
personality epoll_wait tee vmsplice splice \
- open_by_handle_at
+ open_by_handle_at mlock2
CFLAGS-gethostid.c = -fexceptions
CFLAGS-tee.c = -fexceptions -fasynchronous-unwind-tables
tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \
tst-quota tst-sync_file_range tst-sysconf-iov_max tst-ttyname \
- test-errno-linux tst-memfd_create
+ test-errno-linux tst-memfd_create tst-mlock2
# Generate the list of SYS_* macros for the system calls (__NR_*
# macros). The file syscall-names.list contains all possible system
}
GLIBC_2.27 {
memfd_create;
+ mlock2;
}
GLIBC_PRIVATE {
# functions used in other libraries
GLIBC_2.27 glob F
GLIBC_2.27 glob64 F
GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
GLIBC_2.27 strfromf128 F
GLIBC_2.27 strfromf64x F
GLIBC_2.27 strtof128 F
GLIBC_2.27 glob F
GLIBC_2.27 glob64 F
GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
GLIBC_2.27 strfromf128 F
GLIBC_2.27 strfromf64x F
GLIBC_2.27 strtof128 F
GLIBC_2.27 glob F
GLIBC_2.27 glob64 F
GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
GLIBC_2.4 GLIBC_2.4 A
GLIBC_2.4 _Exit F
GLIBC_2.4 _IO_2_1_stderr_ D 0xa0
# define MFD_HUGETLB 4U
# endif
+/* Flags for mlock2. */
+# ifndef MLOCK_ONFAULT
+# define MLOCK_ONFAULT 1U
+# endif
+
__BEGIN_DECLS
/* Create a new memory file descriptor. NAME is a name for debugging.
FLAGS is a combination of the MFD_* constants. */
int memfd_create (const char *__name, unsigned int __flags) __THROW;
+/* Lock pages from ADDR (inclusive) to ADDR + LENGTH (exclusive) into
+ memory. FLAGS is a combination of the MLOCK_* flags above. */
+int mlock2 (const void *__addr, size_t __length, unsigned int __flags) __THROW;
+
__END_DECLS
#endif /* __USE_GNU */
GLIBC_2.27 glob F
GLIBC_2.27 glob64 F
GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
GLIBC_2.3 GLIBC_2.3 A
GLIBC_2.3 __ctype_b_loc F
GLIBC_2.3 __ctype_tolower_loc F
GLIBC_2.27 glob F
GLIBC_2.27 glob64 F
GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
GLIBC_2.27 strfromf64x F
GLIBC_2.27 strtof64x F
GLIBC_2.27 strtof64x_l F
GLIBC_2.27 glob F
GLIBC_2.27 glob64 F
GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
GLIBC_2.27 strfromf64x F
GLIBC_2.27 strtof64x F
GLIBC_2.27 strtof64x_l F
#if __LINUX_KERNEL_VERSION >= 0x031300
# define __ASSUME_EXECVEAT 1
#endif
+
+#if __LINUX_KERNEL_VERSION >= 0x040400
+# define __ASSUME_MLOCK2 1
+#endif
GLIBC_2.27 glob F
GLIBC_2.27 glob64 F
GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
GLIBC_2.4 GLIBC_2.4 A
GLIBC_2.4 _Exit F
GLIBC_2.4 _IO_2_1_stderr_ D 0x98
GLIBC_2.27 glob F
GLIBC_2.27 glob64 F
GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
GLIBC_2.3 GLIBC_2.3 A
GLIBC_2.3 __ctype_b_loc F
GLIBC_2.3 __ctype_tolower_loc F
GLIBC_2.27 glob F
GLIBC_2.27 glob64 F
GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
GLIBC_2.27 glob F
GLIBC_2.27 glob64 F
GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
GLIBC_2.3 GLIBC_2.3 A
GLIBC_2.3 __ctype_b_loc F
GLIBC_2.3 __ctype_tolower_loc F
GLIBC_2.27 glob F
GLIBC_2.27 glob64 F
GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
GLIBC_2.3 GLIBC_2.3 A
GLIBC_2.3 __ctype_b_loc F
GLIBC_2.3 __ctype_tolower_loc F
GLIBC_2.27 glob F
GLIBC_2.27 glob64 F
GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
GLIBC_2.27 strfromf128 F
GLIBC_2.27 strfromf64x F
GLIBC_2.27 strtof128 F
GLIBC_2.27 glob F
GLIBC_2.27 glob64 F
GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
GLIBC_2.27 strfromf128 F
GLIBC_2.27 strfromf64x F
GLIBC_2.27 strtof128 F
--- /dev/null
+/* Wrapper for the mlock2 system call with fallback to mlock.
+ Copyright (C) 2017 Free Software Foundation, Inc.
+
+ 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
+ <http://www.gnu.org/licenses/>. */
+
+#include <sys/mman.h>
+#include <errno.h>
+#include <sysdep.h>
+
+int
+mlock2 (const void *addr, size_t length, unsigned int flags)
+{
+#ifdef __ASSUME_MLOCK2
+ return INLINE_SYSCALL_CALL (mlock2, addr, length, flags);
+#else
+ if (flags == 0)
+ return INLINE_SYSCALL_CALL (mlock, addr, length);
+# ifdef __NR_mlock2
+ int ret = INLINE_SYSCALL_CALL (mlock2, addr, length, flags);
+ if (ret == 0 || errno != ENOSYS)
+ return ret;
+# endif /* __NR_mlock2 */
+ /* Treat the missing system call as an invalid (non-zero) flag
+ argument. */
+ __set_errno (EINVAL);
+ return -1;
+#endif /* __ASSUME_MLOCK2 */
+}
GLIBC_2.27 glob F
GLIBC_2.27 glob64 F
GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
GLIBC_2.27 glob F
GLIBC_2.27 glob64 F
GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
GLIBC_2.3 GLIBC_2.3 A
GLIBC_2.3 __ctype_b_loc F
GLIBC_2.3 __ctype_tolower_loc F
GLIBC_2.27 glob F
GLIBC_2.27 glob64 F
GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
GLIBC_2.3 GLIBC_2.3 A
GLIBC_2.3 __ctype_b_loc F
GLIBC_2.3 __ctype_tolower_loc F
GLIBC_2.27 glob F
GLIBC_2.27 glob64 F
GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
GLIBC_2.27 strfromf64x F
GLIBC_2.27 strtof64x F
GLIBC_2.27 strtof64x_l F
GLIBC_2.27 glob F
GLIBC_2.27 glob64 F
GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
GLIBC_2.3 GLIBC_2.3 A
GLIBC_2.3 _Exit F
GLIBC_2.3 _IO_2_1_stderr_ D 0xe0
GLIBC_2.27 glob F
GLIBC_2.27 glob64 F
GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
GLIBC_2.27 strfromf128 F
GLIBC_2.27 strfromf64x F
GLIBC_2.27 strtof128 F
GLIBC_2.27 glob F
GLIBC_2.27 glob64 F
GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
GLIBC_2.27 strfromf128 F
GLIBC_2.27 strfromf64x F
GLIBC_2.27 strtof128 F
GLIBC_2.27 glob F
GLIBC_2.27 glob64 F
GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
GLIBC_2.3 GLIBC_2.3 A
GLIBC_2.3 __ctype_b_loc F
GLIBC_2.3 __ctype_tolower_loc F
GLIBC_2.27 glob F
GLIBC_2.27 glob64 F
GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
GLIBC_2.27 strfromf128 F
GLIBC_2.27 strfromf64x F
GLIBC_2.27 strtof128 F
GLIBC_2.27 glob F
GLIBC_2.27 glob64 F
GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
GLIBC_2.27 strfromf128 F
GLIBC_2.27 strfromf64x F
GLIBC_2.27 strtof128 F
GLIBC_2.27 glob F
GLIBC_2.27 glob64 F
GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
GLIBC_2.27 glob F
GLIBC_2.27 glob64 F
GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
GLIBC_2.27 glob F
GLIBC_2.27 glob64 F
GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
--- /dev/null
+/* Test the mlock2 function.
+ Copyright (C) 2017 Free Software Foundation, Inc.
+
+ 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
+ <http://www.gnu.org/licenses/>. */
+
+#include <errno.h>
+#include <stdio.h>
+#include <support/check.h>
+#include <support/xunistd.h>
+#include <sys/mman.h>
+
+/* Allocate a page using mmap. */
+static void *
+get_page (void)
+{
+ return xmmap (NULL, 1, PROT_READ | PROT_WRITE,
+ MAP_ANONYMOUS | MAP_PRIVATE, -1);
+}
+
+static int
+do_test (void)
+{
+ /* Current kernels have a small reserve of locked memory, so this
+ test does not need any privileges to run. */
+
+ void *page = get_page ();
+ if (mlock (page, 1) != 0)
+ FAIL_EXIT1 ("mlock: %m\n");
+ xmunmap (page, 1);
+
+ page = get_page ();
+ if (mlock2 (page, 1, 0) != 0)
+ /* Should be implemented using mlock if necessary. */
+ FAIL_EXIT1 ("mlock2 (0): %m\n");
+ xmunmap (page, 1);
+
+ page = get_page ();
+ int ret = mlock2 (page, 1, MLOCK_ONFAULT);
+ if (ret != 0)
+ {
+ TEST_VERIFY (ret == -1);
+ if (errno != EINVAL)
+ /* EINVAL means the system does not support the mlock2 system
+ call. */
+ FAIL_EXIT1 ("mlock2 (0): %m\n");
+ else
+ puts ("warning: mlock2 system call not supported");
+ }
+ xmunmap (page, 1);
+
+ return 0;
+}
+
+#include <support/test-driver.c>
GLIBC_2.27 glob F
GLIBC_2.27 glob64 F
GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
GLIBC_2.27 strfromf64x F
GLIBC_2.27 strtof64x F
GLIBC_2.27 strtof64x_l F
GLIBC_2.27 glob F
GLIBC_2.27 glob64 F
GLIBC_2.27 memfd_create F
+GLIBC_2.27 mlock2 F
GLIBC_2.27 strfromf64x F
GLIBC_2.27 strtof64x F
GLIBC_2.27 strtof64x_l F
git://sourceware.org / glibc.git / commitdiff