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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | STANDARDS | HISTORY | EXAMPLES | SEE ALSO | COLOPHON |
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UFFDIO_COPY(2const) UFFDIO_COPY(2const)
UFFDIO_COPY - atomically copy a continuous memory chunk into the
userfault registered range
Standard C library (libc, -lc)
#include <linux/userfaultfd.h> /* Definition of UFFD* constants */
#include <sys/ioctl.h>
int ioctl(int fd, UFFDIO_COPY, struct uffdio_copy *argp);
#include <linux/userfaultfd.h>
struct uffdio_copy {
__u64 dst; /* Destination of copy */
__u64 src; /* Source of copy */
__u64 len; /* Number of bytes to copy */
__u64 mode; /* Flags controlling behavior of copy */
__s64 copy; /* Number of bytes copied, or negated error */
};
Atomically copy a continuous memory chunk into the userfault
registered range and optionally wake up the blocked thread.
The following value may be bitwise ORed in mode to change the
behavior of the UFFDIO_COPY operation:
UFFDIO_COPY_MODE_DONTWAKE
Do not wake up the thread that waits for page-fault
resolution
UFFDIO_COPY_MODE_WP
Copy the page with read-only permission. This allows the
user to trap the next write to the page, which will block
and generate another write-protect userfault message.
This is used only when both UFFDIO_REGISTER_MODE_MISSING
and UFFDIO_REGISTER_MODE_WP modes are enabled for the
registered range.
The copy field is used by the kernel to return the number of
bytes that was actually copied, or an error (a negated errno-
style value). The copy field is output-only; it is not read by
the UFFDIO_COPY operation.
On success, 0 is returned. In this case, the entire area was
copied.
On error, -1 is returned and errno is set to indicate the error.
EAGAIN The number of bytes copied (i.e., the value returned in
the copy field) does not equal the value that was
specified in the len field.
EINVAL Either dst or len was not a multiple of the system page
size, or the range specified by src and len or dst and len
was invalid.
EINVAL An invalid bit was specified in the mode field.
ENOENT (since Linux 4.11)
The faulting process has changed its virtual memory layout
simultaneously with an outstanding UFFDIO_COPY operation.
ENOSPC (from Linux 4.11 until Linux 4.13)
The faulting process has exited at the time of a
UFFDIO_COPY operation.
ESRCH (since Linux 4.13)
The faulting process has exited at the time of a
UFFDIO_COPY operation.
Linux.
Linux 4.3.
See userfaultfd(2).
ioctl(2), ioctl_userfaultfd(2), userfaultfd(2)
linux.git/Documentation/admin-guide/mm/userfaultfd.rst
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user-space interface documentation) project. Information about
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⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
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2024-06-26. If you discover any rendering problems in this HTML
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Linux man-pages 6.9.1 2024-06-17 UFFDIO_COPY(2const)
Pages that refer to this page: ioctl_userfaultfd(2)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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