MPROTECT(2) System Calls Manual MPROTECT(2)

NAME

mprotectcontrol the protection of pages

LIBRARY

Standard C Library (libc, -lc)

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; the granularity of protection changes may be as large as an entire region.
The protections (region accessibility) are specified in the prot argument by OR'ing the following values:
 
 
PROT_EXEC
Pages may be executed.
 
 
PROT_READ
Pages may be read.
 
 
PROT_WRITE
Pages may be written.
 
 
PROT_NONE
Placeholder when requesting no access permission.

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

 
 
[EACCES]
A memory protection violation occurred.
The PROT_EXEC flag was attempted on pages which belong to a file system mounted with the NOEXEC flag.
The new protection is less restrictive than the protection originally set with mmap(2).
PAX mprotect restrictions prohibit the requested protection.
 
 
[EINVAL]
An invalid memory range, or invalid parameters were provided.
 
 
[ENOMEM]
A resource shortage occurred while internally calling uvm_map_protect(9).

SEE ALSO

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

HISTORY

The mprotect() function first appeared in 4.4BSD.
April 27, 2017 NetBSD 8.2