proc_dostring(9)

💅 proc_dostring(9) — like, the Kernel API Manual one, bestie

okay so picture this: it's a Kernel API Manual page, October 2026 coded, and it's about reading (and writing!!) a string sysctl. yes we're doing kernel plumbing today and yes it slaps. let's go 🫶

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✨ NAME ✨

proc_dostring — read a string sysctl 🌸

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✨ SYNOPSIS ✨

int proc_dostring (const struct ctl_table *table , int dir , void
*buffer , size_t *lenp , loff_t *ppos );

literally the whole signature, don't @ me 🎀

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✨ ARGUMENTS ✨

• table — the sysctl table. that's the vibe, that's the data structure 👑
• dir — TRUE if this is a write to the sysctl file (so like, are we writing or not, bestie, that's the whole question) 💅
• buffer — the user buffer 🦋
• lenp — the size of the user buffer ⭐
• ppos — file position 📍

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✨ DESCRIPTION ✨

So what does it DO. It reads/writes a string from/to the user buffer. that's the main character move ✨

If the kernel buffer provided is not large enough to hold the string, the string is truncated — no cap, it just gets cut off 😭 and the copied string is NULL-terminated.

And if the string is being read by the user process, it's copied and a newline '0 is added. It is truncated if the buffer is not large enough. (yes, both truncation warnings are real, they're not a typo situation, keep both eyes on your buffer sizes fr fr 🙈)

💀 heads up: small buffer = truncated string. every single time. size your buffers, bestie, it's giving self-care.

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✨ RETURN ✨

0 on success. simple. iconic. periodt 🌟

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✨ SEE ALSO ✨

the kernel file ./kernel/sysctl.c, plus this whole squad right here — go read them, they're all lowkey fire 🔥:

• enum sysctl_writes_mode(9)
• proc_first_pos_non_zero_ignore(9)
• strtoul_lenient(9)
• proc_get_long(9)
• proc_put_long(9)
• proc_uint_u2k_conv_uop(9)
• proc_uint_k2u_conv(9)
• proc_uint_conv(9)
• proc_int_k2u_conv_kop(9)
• proc_int_u2k_conv_uop(9)
• proc_int_conv(9)
• proc_douintvec_conv(9)
• proc_dobool(9)
• proc_dointvec(9)
• proc_douintvec(9)
• proc_dointvec_minmax(9)
• proc_douintvec_minmax(9)
• proc_dou8vec_minmax(9)
• proc_ulong_conv(9)
• proc_ulong_u2k_conv_uop(9)
• proc_ulong_k2u_conv_kop(9)
• proc_doulongvec_conv(9)
• proc_doulongvec_minmax(9)
• proc_dointvec_conv(9)
• proc_do_large_bitmap(9)

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and that's the page!! mwah 💋 this one shipped out of ./kernel and it's dated October 2026 — like, future-coded of them honestly. go forth and sysctl responsibly 🧚💜