mprotect(2) System Calls mprotect(2)NAMEmprotect - set protection of memory mapping
SYNOPSIS
#include <sys/mman.h>
int mprotect(void *addr, size_t len, int prot);
DESCRIPTION
The mprotect() function changes the access protections on the mappings
specified by the range [addr, addr + len), rounding len up to the next
multiple of the page size as returned by sysconf(3C), to be that speci‐
fied by prot. Legitimate values for prot are the same as those permit‐
ted for mmap(2) and are defined in <sys/mman.h> as:
PROT_READ /* page can be read */
PROT_WRITE /* page can be written */
PROT_EXEC /* page can be executed */
PROT_NONE /* page can not be accessed */
When mprotect() fails for reasons other than EINVAL, the protections on
some of the pages in the range [addr, addr + len) may have been
changed. If the error occurs on some page at addr2, then the protec‐
tions of all whole pages in the range [addr, addr2] will have been mod‐
ified.
RETURN VALUES
Upon successful completion, mprotect() returns 0. Otherwise, it returns
−1 and sets errno to indicate the error.
ERRORS
The mprotect() function will fail if:
EACCES The prot argument specifies a protection that violates
the access permission the process has to the underlying
memory object.
EINVAL The len argument has a value equal to 0, or addr is not
a multiple of the page size as returned by sysconf(3C).
ENOMEM Addresses in the range [addr, addr + len) are invalid
for the address space of a process, or specify one or
more pages which are not mapped.
The mprotect() function may fail if:
EAGAIN The address range [addr, addr + len) includes one or
more pages that have been locked in memory and that
were mapped MAP_PRIVATE; prot includes PROT_WRITE; and
the system has insufficient resources to reserve memory
for the private pages that may be created. These pri‐
vate pages may be created by store operations in the
now-writable address range.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Standard │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOmmap(2), plock(3C), mlock(3C), mlockall(3C), sysconf(3C),
attributes(5), standards(5)SunOS 5.10 12 Jan 1998 mprotect(2)
