|MPROTECT(3P)||POSIX Programmer's Manual||MPROTECT(3P)|
int mprotect(void *addr, size_t len, int prot);
If an implementation cannot support the combination of access types specified by prot, the call to mprotect() shall fail.
An implementation may permit accesses other than those specified by prot; however, no implementation shall permit a write to succeed where PROT_WRITE has not been set or shall permit any access where PROT_NONE alone has been set. Implementations shall support at least the following values of prot: PROT_NONE, PROT_READ, PROT_WRITE, and the bitwise-inclusive OR of PROT_READ and PROT_WRITE. If PROT_WRITE is specified, the application shall ensure that it has opened the mapped objects in the specified address range with write permission, unless MAP_PRIVATE was specified in the original mapping, regardless of whether the file descriptors used to map the objects have since been closed.
The implementation may require that addr be a multiple of the page size as returned by sysconf().
The behavior of this function is unspecified if the mapping was not established by a call to mmap().
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.
- The prot argument specifies a protection that violates the access permission the process has to the underlying memory object.
- The prot argument specifies PROT_WRITE over a MAP_PRIVATE mapping and there are insufficient memory resources to reserve for locking the private page.
- 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 prot argument specifies PROT_WRITE on a MAP_PRIVATE mapping, and it would require more space than the system is able to supply for locking the private pages, if required.
- The implementation does not support the combination of accesses requested in the prot argument.
The mprotect() function may fail if:
- The addr argument is not a multiple of the page size as returned by sysconf().
The following sections are informative.
The Base Definitions volume of POSIX.1‐2017, <sys_mman.h>
Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .
|2017||IEEE/The Open Group|