DragonFly On-Line Manual Pages

MPROTECT(2)		 DragonFly System Calls Manual		   MPROTECT(2)


mprotect -- control the protection of pages


Standard C Library (libc, -lc)


#include <sys/types.h> #include <sys/mman.h> int mprotect(void *addr, size_t len, int prot);


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. A region is the virtual address space defined by the start and end addresses of a struct vm_map_entry. Currently these protection bits are known, which can be combined, OR'd together: PROT_NONE No permissions at all. PROT_READ The pages can be read. PROT_WRITE The pages can be written. PROT_EXEC The pages can be executed.


The mprotect() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error.


The mprotect() function will fail if: [EINVAL] The virtual address range specified by the addr and len arguments is not valid. [EACCES] The calling process was not allowed to change the pro- tection to the value specified by the prot argument.


madvise(2), mincore(2), msync(2), munmap(2)


The mprotect() function first appeared in 4.4BSD. DragonFly 4.3 January 31, 2010 DragonFly 4.3