MPROTECT(2) System Calls Manual MPROTECT(2)

mprotectcontrol the protection of pages

#include <sys/mman.h>

int
mprotect(void *addr, size_t len, int prot);

The () 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:

No permissions at all.
The pages can be read.
The pages can be written.
The pages can be executed.

Upon successful completion, a value of 0 is returned. Otherwise, a value of -1 is returned and errno is set to indicate the error.

mprotect() will fail if:

[]
The requested protection conflicts with the access permissions of the process on the specified address range.
[]
addr is not a multiple of the page size (i.e. addr is not page-aligned).
[]
The specified address range is outside of the address range of the process or includes an unmapped page.
[]
The combination of accesses requested in prot is not supported.

#include <sys/types.h> #include <sys/mman.h>

The include file <sys/types.h> is necessary.

int
(caddr_t addr, size_t len, int prot);;

The type of addr has changed.

madvise(2), mincore(2), msync(2), munmap(2), compat(5)

The mprotect() function first appeared in 4.4BSD.

October 16, 2008 macOS 14.4