OpenPAM/lib/libpam/openpam_straddch.c
2021-10-22 17:21:48 +02:00

113 lines
3.6 KiB
C

/*-
* Copyright (c) 2012 Dag-Erling Smørgrav
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <errno.h>
#include <stdlib.h>
#include <security/pam_appl.h>
#include "openpam_impl.h"
#define MIN_STR_SIZE 32
/*
* OpenPAM extension
*
* Add a character to a string, expanding the buffer if needed.
*/
int
openpam_straddch(char **str, size_t *size, size_t *len, int ch)
{
size_t tmpsize;
char *tmpstr;
if (*str == NULL) {
/* initial allocation */
tmpsize = MIN_STR_SIZE;
if ((tmpstr = malloc(tmpsize)) == NULL) {
errno = ENOMEM;
return (-1);
}
*str = tmpstr;
*size = tmpsize;
*len = 0;
} else if (ch != 0 && *len + 1 >= *size) {
/* additional space required */
tmpsize = *size * 2;
if ((tmpstr = realloc(*str, tmpsize)) == NULL) {
errno = ENOMEM;
return (-1);
}
*size = tmpsize;
*str = tmpstr;
}
if (ch != 0) {
(*str)[*len] = ch;
++*len;
}
(*str)[*len] = '\0';
return (0);
}
/**
* The =openpam_straddch function appends a character to a dynamically
* allocated NUL-terminated buffer, reallocating the buffer as needed.
*
* The =str argument points to a variable containing either a pointer to
* an existing buffer or =NULL.
* If the value of the variable pointed to by =str is =NULL, a new buffer
* is allocated.
*
* The =size and =len argument point to variables used to hold the size
* of the buffer and the length of the string it contains, respectively.
*
* The final argument, =ch, is the character that should be appended to
* the string. If =ch is 0, nothing is appended, but a new buffer is
* still allocated if =str is NULL. This can be used to "bootstrap" the
* string.
*
* If a new buffer is allocated or an existing buffer is reallocated to
* make room for the additional character, =str and =size are updated
* accordingly.
*
* The =openpam_straddch function ensures that the buffer is always
* NUL-terminated.
*
* If the =openpam_straddch function is successful, it increments the
* integer variable pointed to by =len (unless =ch was 0) and returns 0.
* Otherwise, it leaves the variables pointed to by =str, =size and =len
* unmodified, sets :errno to =ENOMEM and returns -1.
*
* AUTHOR DES
*/