PGET(9)

💅 PGET — locate a process by number 💅

okay bestie, welcome to pget(9), straight out of the Kernel Developer's Manual (yes we read kernel docs for fun now, it's a whole personality) ✨

🎀 NAME 🎀

pget — find a process by its number, fr fr 🔍

✨ SYNOPSIS ✨

#include <sys/param.h>
#include <sys/proc.h>

int
pget(pid_t pid, int flags, struct proc **pp);

like, that's the whole vibe. three args, one pointer-to-pointer, zero chill 🫶

🦋 DESCRIPTION 🦋

so the way this works is: you hand pget() a pid, and that pid can be either a process id or a thread id — it's flexible like that 💁‍♀️ — and then it fills in a pointer to the proc structure into *pp. and if you gave it a thread id? no worries, it goes looking for the process that owns that thread. queen behavior 👑

the actual finding is done by calling the pfind(9) function, iykyk.

now here's the part you gotta remember, bestie: the found process comes back LOCKED. 🔒 but if you passed PGET_HOLD, it comes back unlocked instead (but held — which is a whole different thing, don't mix them up 😭).

and depending on what you put in flags, pget() will do extra little manipulations on top. it's giving ✨customizable✨.

the flags argument is the logical OR of some subset of these:

• PGET_HOLD — if set, the found process gets held and unlocked. (the opposite-lock vibe, we love her 🌸)
• PGET_CANSEE — if set, the found process gets its visibility checked. see p_cansee(9) 👀
• PGET_CANDEBUG — if set, the found process gets checked for debuggability. see p_candebug(9) 🐛
• PGET_ISCURRENT — if set, the found process gets checked that it matches the current process context. "is it me? am I the drama?" 🪞
• PGET_NOTWEXIT — if set, the found process gets checked that it does not have the process flag P_WEXIT set. 🚪
• PGET_NOTINEXEC — if set, the found process gets checked that it does not have the process flag P_INEXEC set. 🏃‍♀️
• PGET_NOTID — if set, pid is not assumed as a thread id for values larger than PID_MAX. 🔢
• PGET_WANTREAD — if set, the found process gets checked that the caller may get read access to its structure. it's literally a shorthand for (PGET_HOLD | PGET_CANDEBUG | PGET_NOTWEXIT) 💖

🌈 RETURN VALUES 🌈

if the process is found in the specified way → zero gets returned, slay ✨

otherwise → an appropriate error code comes back instead. not slay 💀

👑 SEE ALSO 👑

p_candebug(9), p_cansee(9), pfind(9) — go read your siblings, they're iconic too 🫶

and that's the whole page, bestie 💜 this one's from Debian, dated May 3, 2014 — vintage, honestly. go lock a process responsibly, mwah 😘💅