X509_STORE_CTX_GET_BY_SUBJECT(3SSL)

📦
version 4.0.3 · 7 versions
, in ubuntu stonking

💖 X509_STORE_CTX_GET_BY_SUBJECT 💖

okay bestie, gather round, because today we're talking about two little lookup girlies from the OpenSSL family, and they live in the X509_STORE_CTX_GET_BY_SUBJECT(3SSL) manual page. yes, that's the whole name, it's giving "my parents gave me a hyphenated surname" energy and honestly? iconic.

✨ NAME ✨

X509_STORE_CTX_get_by_subject, X509_STORE_CTX_get_obj_by_subject — these are your X509 and X509_CRL lookup functions. that's the whole job. they find stuff. 🦋

✨ SYNOPSIS ✨

like, first you gotta bring the right header or it's not gonna know you:

#include <openssl/x509_vfy.h>

int X509_STORE_CTX_get_by_subject(const X509_STORE_CTX *vs,
                                  X509_LOOKUP_TYPE type,
                                  const X509_NAME *name, X509_OBJECT *ret);
X509_OBJECT *X509_STORE_CTX_get_obj_by_subject(X509_STORE_CTX *vs,
                                               X509_LOOKUP_TYPE type,
                                               const X509_NAME *name);

no cap, copy that verbatim, every comma matters. 💅

✨ DESCRIPTION ✨

okay so X509_STORE_CTX_get_by_subject() is out here trying to find an object of a given type — and that type may be X509_LU_X509 or X509_LU_CRL — plus a subject name, and it's digging through the store inside the store context you handed it as vs. 🎀

and the tea is: if it does find it, and ret is not NULL, it increments the reference count and stashes the looked-up object into ret. so like, you're holding a whole extra ref now. don't forget her. 😭

then we have X509_STORE_CTX_get_obj_by_subject(), which is literally the same vibe as X509_STORE_CTX_get_by_subject() except it just returns the found object on success, and NULL otherwise. no ret param, no counting drama, just "here's your object bestie" or "sorry, nothing" 🫶

✨ NOTES ✨

these functions are safe to use in a multithreaded environment and with lookup functions on the same store. slay. multithreaded queen. 🔥

but listen — if multiple applications are sharing one store across threads, they should manage its lifetime with X509_STORE_up_ref(3) and X509_STORE_free(3), and they must make sure that all lookup operations have finished before the store gets freed. like, do not free the store while lookups are still out there living their lives, that's not a vibe. 💀

if you want the full discussion of the X509_STORE threading model, go read "Thread Safety" in X509_STORE_new(3). iykyk. 📚

✨ RETURN VALUES ✨

  • X509_STORE_CTX_get_by_subject() — returns 1 if the lookup was successful, else 0. simple. binary. main character energy. ⭐
  • X509_STORE_CTX_get_obj_by_subject() — returns an object on success, else NULL. 🙈
fr fr, check your return values, bestie. NULL is not a personality trait, it's an error.

✨ SEE ALSO ✨

go read those next, it's giving "syllabus" but make it cute. 🌸

Copyright 2022-2026 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <https://www.openssl.org/source/license.html>.

and that's the whole page, babe 💖 this was OpenSSL 4.0.3, dated 2026-09-2, and honestly? she ate. periodt. 👑🌈🧚

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