mprotect

Name

mprotect - controls allowable accesses to a region of memory

Library

libc.lib

Synopsis

#include <sys/mman.h>

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

Return values

Upon successful completion, mprotect returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the
error.

Detailed 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. A region is the virtual address space defined by the start and end addresses of a struct vm_map_entry .

NOTE: This interface is currently not functional and only build supported. This is because of the fact that, mmap used for mapping, internally uses shared memory facility provided by the platform and shared memory interface does not support dynamic modification of memory protections.

Currently these protection bits are known, which can be combined, OR’d together:

`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.

Errors

The 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.

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