|MPROTECT(2)||FreeBSD System Calls Manual||MPROTECT(2)|
NAMEmprotect — control the protection of pages
LIBRARYStandard C Library (libc, -lc)
SYNOPSIS#include < sys/mman.h>
mprotect( const void *addr, size_t len, int prot);
DESCRIPTIONThe 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. A region is the virtual address space defined by the start and end addresses of a struct vm_map_entry.
Currently these protection bits are known, which can be combined, OR'd together:
- No permissions at all.
- The pages can be read.
- The pages can be written.
- The pages can be executed.
RETURN VALUESThe mprotect() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error.
ERRORSThe mprotect() system call will fail if:
- [ EINVAL]
- The virtual address range specified by the addr and len arguments is not valid.
- [ EACCES]
- The calling process was not allowed to change the protection to the value specified by the prot argument.
HISTORYThe mprotect() system call first appeared in 4.4BSD.
|June 9, 1993||FreeBSD|