VM_PAGE_PROTECT(9) BSD Kernel Developer's Manual VM_PAGE_PROTECT(9)NAME
vm_page_protect -- lower a page's protection
SYNOPSIS
#include <sys/param.h>
#include <vm/vm.h>
#include <vm/vm_page.h>
void
vm_page_protect(vm_page_t mem, int prot);
DESCRIPTION
The vm_page_protect() function lowers a page's protection. The protection is never raised by this function; therefore, if the page is
already at VM_PROT_NONE, the function does nothing.
Its arguments are:
mem The page whose protection is lowered.
prot The protection the page should be reduced to. If VM_PROT_NONE is specified, then the PG_WRITABLE and PG_MAPPED flags are cleared and
the pmap_page's protection is set to VM_PROT_NONE. If VM_PROT_READ is specified, then the PG_WRITABLE flag is cleared and the
pmap_page's protection is set to VM_PROT_READ.
Higher protection requests are ignored.
AUTHORS
This manual page was written by Chad David <davidc@acns.ab.ca>.
BSD July 14, 2001 BSD
Check Out this Related Man Page
MPROTECT(2) BSD System Calls Manual MPROTECT(2)NAME
mprotect -- control the protection of pages
SYNOPSIS
#include <sys/mman.h>
int
mprotect(void *addr, size_t len, int prot);
DESCRIPTION
The mprotect() system call changes the specified pages to have protection prot. Not all implementations will guarantee protection on a page
basis but Mac OS X's current implementation does.
When a program violates the protections of a page, it gets a SIGBUS or SIGSEGV signal.
Currently prot can be one or more of the following:
PROT_NONE No permissions at all.
PROT_READ The pages can be read.
PROT_WRITE The pages can be written.
PROT_EXEC The pages can be executed.
RETURN VALUES
Upon successful completion, a value of 0 is returned. Otherwise, a value of -1 is returned and errno is set to indicate the error.
ERRORS
mprotect() will fail if:
[EACCES] The requested protection conflicts with the access permissions of the process on the specified address range.
[EINVAL] addr is not a multiple of the page size (i.e. addr is not page-aligned).
[ENOTSUP] The combination of accesses requested in prot is not supported.
LEGACY SYNOPSIS
#include <sys/types.h>
#include <sys/mman.h>
The include file <sys/types.h> is necessary.
int
mprotect(caddr_t addr, size_t len, int prot);
The type of addr has changed.
SEE ALSO madvise(2), mincore(2), msync(2), munmap(2), compat(5)HISTORY
The mprotect() function first appeared in 4.4BSD.
BSD October 16, 2008 BSD
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