proc_douintvec_minmax(9)

okay bestie, welcome to proc_douintvec_minmax(9) from the Kernel API Manual 💅✨. This is the sysctl routine that reads a vector of unsigned ints with min/max values, and it's lowkey iconic.

💖 NAME 💖

proc_douintvec_minmax — read a vector of unsigned ints with min/max values. periodt.

✨ SYNOPSIS ✨

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

🫶 ARGUMENTS 🫶

• table — the sysctl table. it's giving metadata main character energy.
• dir — TRUE if this is a write to the sysctl file. read vs write vibe check, basically.
• buffer — the user buffer. where the values hang out.
• lenp — the size of the user buffer. mind the length, bestie.
• ppos — file position. it knows where we are in the file.

🌸 DESCRIPTION 🌸

Reads/writes up to table->maxlen/sizeof(unsigned int) unsigned integer values from/to the user buffer, treated as an ASCII string. Negative strings are not allowed — literally not allowed, no cap 😭.

When changing the kernel variable, this routine will ensure the values are within the range specified by table->extra1 (min) and table->extra2 (max). And it checks that the values are less than UINT_MAX to avoid having to support wrap around uses from userspace. So yeah, min/max boundaries are the whole moment, and UINT_MAX is the ceiling we do not cross. ✨

⭐ RETURN ⭐

0 on success, or -ERANGE when the range check failes and SYSCTL_USER_TO_KERN(dir) == true.

🦋 SEE ALSO 🦋

okay, the lore is deep — here's the whole friend group 💜:

• Kernel file ./kernel/sysctl.c and enum sysctl_writes_mode(9)
• proc_first_pos_non_zero_ignore(9)
• proc_dostring(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_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)

xoxo, your kernel bestie 💅 — source ./kernel, dated October 2026. go read a sysctl for me 🫶