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mprotect(2) [opensolaris man page]

mprotect(2)							   System Calls 						       mprotect(2)

NAME
mprotect - 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 specified by prot. Legitimate values for prot are the same as those permitted 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 protections of all whole pages in the range [addr, addr2] will have been modi- fied. 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 private 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 ALSO
mmap(2), plock(3C), mlock(3C), mlockall(3C), sysconf(3C), attributes(5), standards(5) SunOS 5.11 12 Jan 1998 mprotect(2)

Check Out this Related Man Page

MPROTECT(3P)						     POSIX Programmer's Manual						      MPROTECT(3P)

PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the correspond- ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux. NAME
mprotect - set protection of memory mapping SYNOPSIS
#include <sys/mman.h> int mprotect(void *addr, size_t len, int prot); DESCRIPTION
The mprotect() function shall change the access protections to be that specified by prot for those whole pages containing any part of the address space of the process starting at address addr and continuing for len bytes. The parameter prot determines whether read, write, exe- cute, or some combination of accesses are permitted to the data being mapped. The prot argument should be either PROT_NONE or the bitwise- inclusive OR of one or more of PROT_READ, PROT_WRITE, and PROT_EXEC. 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 fol- lowing values of prot: PROT_NONE, PROT_READ, PROT_WRITE, and the bitwise-inclusive OR of PROT_READ and PROT_WRITE. If PROT_WRITE is speci- fied, 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 shall 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. RETURN VALUE
Upon successful completion, mprotect() shall return 0; otherwise, it shall return -1 and set errno to indicate the error. ERRORS
The mprotect() function shall fail if: EACCES The prot argument specifies a protection that violates the access permission the process has to the underlying memory object. EAGAIN The prot argument specifies PROT_WRITE over a MAP_PRIVATE mapping and there are insufficient memory resources to reserve for locking the private page. EINVAL The addr argument is not a multiple of the page size as returned by sysconf(). 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. ENOMEM 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. ENOTSUP The implementation does not support the combination of accesses requested in the prot argument. The following sections are informative. EXAMPLES
None. APPLICATION USAGE
The [EINVAL] error above is marked EX because it is defined as an optional error in the POSIX Realtime Extension. RATIONALE
None. FUTURE DIRECTIONS
None. SEE ALSO
mmap(), sysconf(), the Base Definitions volume of IEEE Std 1003.1-2001, <sys/mman.h> COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol- ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html . IEEE
/The Open Group 2003 MPROTECT(3P)
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