PR_SET_MDWE(2const)

✨ PR_SET_MDWE(2const) ✨

okay bestie, welcome to the PR_SET_MDWE(2const) page — it's a section 2 const page from the Linux man-pages crew, and we're about to lock your process down like it's the last slice of cake at a party. 🎀

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🌸 NAME 🌸

PR_SET_MDWE — set the Memory-Deny-Write-Execute protection mask for the calling process. it's giving "no W + X for you, ever again." 💅

📚 LIBRARY 📚

Standard C library (libc, -lc). yep, the classics. 🫶

🦋 SYNOPSIS 🦋

so here's the summoning circle:

#include <linux/prctl.h>  /* Definition of PR_* constants */
#include <sys/prctl.h>

int prctl(PR_SET_MDWE, unsigned long mask, 0L, 0L, 0L);

💖 DESCRIPTION 💖

OK so what this actually does: it sets the calling process' Memory-Deny-Write-Execute protection mask. like, you're telling the kernel "bestie, I do not want memory that is writable and executable at the same time, thank you very much." 🧚

and here's the dramatic part: Once protection bits are set, they can not be changed. no take-backs. no undo. periodt. 💀

mask has to be a bit mask made of these:

• PR_MDWE_REFUSE_EXEC_GAIN — new memory mappings can't be both writable and executable, and non-executable mappings can't become executable later. it's a whole vibe lock. 🔒
• PR_MDWE_NO_INHERIT (since Linux 6.6) — do not pass the MDWE protection down to child processes on fork(2). heads up though: setting this bit requires that you also set PR_MDWE_REFUSE_EXEC_GAIN. no solo acts, they're a package deal. 👑

⭐ RETURN VALUE ⭐

• On success: 0 is returned. slay. ✨
• On error: -1 is returned, and errno is set to tell you what went wrong. 😭

🙈 ERRORS 🙈

• EINVAL — mask is not a valid value. you handed the kernel a mask it simply cannot process. try again, but cute this time. 💅

🌈 STANDARDS 🌈

Linux. that's the whole answer. 🇱🇮🇳🇺🇽

👑 HISTORY 👑

Linux 6.3. so it's a relatively fresh baby, glow-up complete. 🦋

🔥 SEE ALSO 🔥

• prctl(2)
• PR_GET_MDWE(2const)

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and that's the whole page, bestie — no cap, we kept every single bit (heh) of it 💖✨🎀

cute sign-off: this page came to you courtesy of Linux man-pages 6.20, dated 2026-01-17. stay locked down, stay iconic. 🫶🌸💅