mprotect(2) [netbsd man page]

MPROTECT(2)						      BSD 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.

BSD
								   April 3, 2011							       BSD

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)