mprotect(2) - NetBSD Manual Pages

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MPROTECT(2)               NetBSD 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     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 pro-
                        tection originally set with mmap(2).

                        PaX mprotect restrictions prohibit the requested pro-
                        tection.

     [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.

NetBSD 9.0                      April 27, 2017                      NetBSD 9.0