MPROTECT(2)

MPROTECT(2) | System Calls Manual | MPROTECT(2)

# NAME

mprotect — control 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
  No permissions.

# 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, or the PROT_EXEC flag was attempted on pages which belong to a filesystem mounted with the NOEXEC flag.
[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 3, 2011 | NetBSD 7.1