shadow/libmisc/loginprompt.c
Alejandro Colomar 62172f6fb5 Call NULL by its name
In variadic functions we still do the cast.  In POSIX, it's not
necessary, since NULL is required to be of type 'void *', and 'void *'
is guaranteed to have the same alignment and representation as 'char *'.
However, since ISO C still doesn't mandate that, and moreover they're
doing dubious stuff by adding nullptr, let's be on the cautious side.
Also, C++ requires that NULL is _not_ 'void *', but either plain 0 or
some magic stuff.

Signed-off-by: Alejandro Colomar <alx@kernel.org>
2023-02-02 13:08:30 -06:00

149 lines
3.1 KiB
C

/*
* SPDX-FileCopyrightText: 1989 - 1993, Julianne Frances Haugh
* SPDX-FileCopyrightText: 1996 - 2000, Marek Michałkiewicz
* SPDX-FileCopyrightText: 2003 - 2005, Tomasz Kłoczko
* SPDX-FileCopyrightText: 2008 - 2011, Nicolas François
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <config.h>
#ident "$Id$"
#include <assert.h>
#include <stdio.h>
#include <signal.h>
#include <ctype.h>
#include "prototypes.h"
#include "defines.h"
#include "getdef.h"
static void login_exit (unused int sig)
{
exit (EXIT_FAILURE);
}
/*
* login_prompt - prompt the user for their login name
*
* login_prompt() displays the standard login prompt. If ISSUE_FILE
* is set in login.defs, this file is displayed before the prompt.
*/
void login_prompt (const char *prompt, char *name, int namesize)
{
char buf[1024];
#define MAX_ENV 32
char *envp[MAX_ENV];
char *cp;
int i;
FILE *fp;
sighandler_t sigquit;
sighandler_t sigtstp;
/*
* There is a small chance that a QUIT character will be part of
* some random noise during a prompt. Deal with this by exiting
* instead of core dumping. Do the same thing for SIGTSTP.
*/
sigquit = signal (SIGQUIT, login_exit);
sigtstp = signal (SIGTSTP, login_exit);
/*
* See if the user has configured the issue file to
* be displayed and display it before the prompt.
*/
if (NULL != prompt) {
const char *fname = getdef_str ("ISSUE_FILE");
if (NULL != fname) {
fp = fopen (fname, "r");
if (NULL != fp) {
while ((i = getc (fp)) != EOF) {
(void) putc (i, stdout);
}
(void) fclose (fp);
}
}
(void) gethostname (buf, sizeof buf);
printf (prompt, buf);
(void) fflush (stdout);
}
/*
* Read the user's response. The trailing newline will be
* removed.
*/
memzero (buf, sizeof buf);
if (fgets (buf, (int) sizeof buf, stdin) != buf) {
exit (EXIT_FAILURE);
}
cp = strchr (buf, '\n');
if (NULL == cp) {
exit (EXIT_FAILURE);
}
*cp = '\0'; /* remove \n [ must be there ] */
/*
* Skip leading whitespace. This makes " username" work right.
* Then copy the rest (up to the end or the first "non-graphic"
* character into the username.
*/
for (cp = buf; *cp == ' ' || *cp == '\t'; cp++);
for (i = 0; i < namesize - 1 && isgraph (*cp); name[i++] = *cp++);
while (isgraph (*cp)) {
cp++;
}
if ('\0' != *cp) {
cp++;
}
name[i] = '\0';
/*
* This is a disaster, at best. The user may have entered extra
* environmental variables at the prompt. There are several ways
* to do this, and I just take the easy way out.
*/
if ('\0' != *cp) { /* process new variables */
char *nvar;
int count = 1;
int envc;
for (envc = 0; envc < MAX_ENV; envc++) {
nvar = strtok ((0 != envc) ? NULL : cp, " \t,");
if (NULL == nvar) {
break;
}
if (strchr (nvar, '=') != NULL) {
envp[envc] = nvar;
} else {
size_t len = strlen (nvar) + 32;
envp[envc] = xmalloc (len);
(void) snprintf (envp[envc], len,
"L%d=%s", count++, nvar);
}
}
set_env (envc, envp);
}
/*
* Set the SIGQUIT handler back to its original value
*/
(void) signal (SIGQUIT, sigquit);
(void) signal (SIGTSTP, sigtstp);
}