The openpam_readline function reads a line from a file, and returns it in a NUL-terminated buffer allocated with malloc(3).
The openpam_readline function performs a certain amount of processing on the data it reads. Comments (introduced by a hash sign) are stripped, as is leading and trailing whitespace. Any amount of linear whitespace is collapsed to a single space. Blank lines are ignored. If a line ends in a backslash, the backslash is stripped and the next line is appended.
If lineno is not NULL, the integer variable it points to is incremented every time a newline character is read.
If lenp is not NULL, the length of the line (not including the terminating NUL character) is stored in the variable it points to.
The caller is responsible for releasing the returned buffer by passing it to free(3).
The openpam_readline function returns NULL on failure.
free(3), malloc(3), pam(3)