MPROTECT(2) NetBSD System Calls Manual MPROTECT(2)
mprotect -- control the protection of pages
Standard C Library (libc, -lc)
#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. 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.
Upon successful completion, a value of 0 is returned. Otherwise, a value of -1 is returned and errno is set to indicate the error.
[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).
madvise(2), mincore(2), msync(2), munmap(2)
The mprotect() function first appeared in 4.4BSD. NetBSD 8.1 April 27, 2017 NetBSD 8.1
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