PAM_PUTENV(3)

💅 PAM_PUTENV(3) — like, the pam_putenv situation

okay so bestie, this is a page from the Linux-PAM Manual, and it's all about pam_putenv — the function that sets or changes PAM environment variables. yes the title is literally pam_putenv - set or change PAM environment variable. iykyk. let's get into it 🫶

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✨ SYNOPSIS ✨

#include <security/pam_appl.h>

int pam_putenv(pam_handle_t *pamh, const char *name_value);

that's it. that's the whole vibe. two args, one int back. slay. 💅

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🌸 DESCRIPTION 🌸

so the pam_putenv function is the one you call when you want to add or change the value of PAM environment variables as associated with the pamh handle. that's the whole job, and honestly? she does it.

the pamh argument is an authentication handle obtained by a prior call to pam_start(). no pam_start() first = no handle = we're not doing anything, bestie.

the name_value argument is a single NUL terminated string of one of the following forms — and this part is lowkey the most important part, so pay attention 🎀:

• NAME=value of variable — in this case the environment variable of the given NAME is set to the indicated value: value of variable. if this variable is already known, it is overwritten. otherwise it is added to the PAM environment. classic main character behavior, honestly.
• NAME= — this one sets the variable to an empty value. and yes, it's listed separately on purpose, to indicate that this is the correct way to achieve such a setting. not me writing NAME= and thinking i did something — no, i actually did something. that's the point. 🙈
• NAME — without an '=' the pam_putenv() function will delete the corresponding variable from the PAM environment. it's giving "exiting the group chat." bye bestie 💀

⚠️ important tea: pam_putenv() operates on a copy of name_value, which means — in contrast to putenv(3) — the application is responsible for freeing the data. yes, you have to free it. not her. you. don't forget. i'm not gonna remind you again (i will) 😭

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🦋 RETURN VALUES 🦋

here's the vibe check on what you get back. all of these are exactly as written, no cap:

• PAM_PERM_DENIED — the argument name_value given is a NULL pointer. she said no. 🚫
• PAM_BAD_ITEM — the variable requested (for deletion) is not currently set. you tried to delete something that doesn't exist. awk. 💀
• PAM_ABORT — the pamh handle is corrupt. something is deeply wrong and it's not your fault (maybe it is). 😭
• PAM_BUF_ERR — memory buffer error. the memory said "not today." 🍓
• PAM_SUCCESS — the environment variable was successfully updated. slay!! 🎉👑 this is the one you want. this is the goal. periodt.

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👑 SEE ALSO 👑

go read these next, bestie, they all hang out together:

• pam_start(3)
• pam_getenv(3)
• pam_getenvlist(3)
• pam_strerror(3)
• pam(8)

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and that's the whole page 💜

cute little sign-off: this iconic piece of documentation comes from Linux-PAM, dated 07/08/2026, and the page itself is PAM_PUTENV(3) — okay byeee, go set some environment variables responsibly, mwah 🧚✨💖