MPROTECT(2)

💅 MPROTECT(2) — it's giving "system calls manual" ✨

okay bestie, welcome to mprotect — the System Calls Manual page that lets you change what your memory is allowed to do. protection? we're controlling it. periodt.

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🎀 NAME 🎀

mprotect — control the protection of pages

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📚 LIBRARY 📚

Standard C Library (libc, -lc)

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✨ SYNOPSIS ✨

#include <sys/mman.h>

int
mprotect(void *addr, size_t len, int prot);

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🦋 DESCRIPTION 🦋

so like. the mprotect() system call changes the specified pages so they have protection prot. that's the whole vibe. 🔥

ngl tho, not every implementation is gonna guarantee protection on a page basis — the granularity of protection changes can be as large as an entire region. and a region? it's the virtual address space defined by the start and end addresses of a struct vm_map_entry. iykyk.

currently these protection bits are known, and you can combine them, OR'd together:

• PROT_NONE — No permissions at all. literally none. 🙈
• PROT_READ — The pages can be read.
• PROT_WRITE — The pages can be written.
• PROT_EXEC — The pages can be executed.

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💖 RETURN VALUES 💖

the mprotect() function returns the value 0 if successful — slay. otherwise the value -1 is returned and the global variable errno is set to indicate the error. not slay. 😭

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💀 ERRORS 💀

the mprotect() system call will fail if:

• [EACCES] — The calling process was not allowed to change the protection to the value specified by the prot argument. bestie you do NOT have permission 💅
• [EINVAL] — The virtual address range specified by the addr and len arguments is not valid.

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🌈 SEE ALSO 🌈

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

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👑 HISTORY 👑

the mprotect() system call first appeared in 4.4BSD. iconic behavior, honestly. ⭐

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🫶 and that's the whole page, bestie!! this one's from Debian, dated August 3, 2016 — go protect some pages, main character energy only. 💖✨🌸