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
- 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.