OPENPAM_SUBST(3)

OPENPAM_SUBST(3) | Library Functions Manual | OPENPAM_SUBST(3)

# NAME

`openpam_subst` — substitute PAM item values in a string

# SYNOPSIS

`#include <sys/types.h>`
`#include <security/pam_appl.h>`
`#include <security/openpam.h>`

int
`openpam_subst`(const pam_handle_t *pamh, char *buf, size_t *bufsize, const char *template);

# DESCRIPTION

The `openpam_subst`() function expands a string, substituting PAM item values for all occurrences of specific substitution codes. The template argument points to the initial string. The result is stored in the buffer pointed to by the buf argument; the bufsize argument specifies the size of that buffer. The actual size of the resulting string, including the terminating NUL character, is stored in the location pointed to by the bufsize argument.

If buf is NULL, or if the buffer is too small to hold the expanded string, bufsize is updated to reflect the amount of space required to hold the entire string, and `openpam_subst`() returns `PAM_TRY_AGAIN`.

If `openpam_subst`() fails for any other reason, the bufsize argument is untouched, but part of the buffer may still have been overwritten.

Substitution codes are introduced by a percent character and correspond to PAM items:

%H
  Replaced by the current value of the `PAM_RHOST` item.
%h
  Replaced by the current value of the `PAM_HOST` item.
%s
  Replaced by the current value of the `PAM_SERVICE` item.
%t
  Replaced by the current value of the `PAM_TTY` item.
%U
  Replaced by the current value of the `PAM_RUSER` item.
%u
  Replaced by the current value of the `PAM_USER` item.

# RETURN VALUES

The `openpam_subst`() function returns one of the following values:

[`PAM_SUCCESS`]
  Success.
[`PAM_BAD_ITEM`]
  Unrecognized or restricted item.
[`PAM_TRY_AGAIN`]
  Try again.

# SEE ALSO

pam(3), pam_get_authtok(3), pam_get_item(3), pam_get_user(3), pam_strerror(3)

# STANDARDS

The `openpam_subst`() function is an OpenPAM extension.

# AUTHORS

The `openpam_subst`() function and this manual page were developed by Dag-Erling Smørgrav <des@des.no>.

June 27, 2023 | NetBSD 11.0