ydb/contrib/libs/libc_compat/readpassphrase.c

/*    $OpenBSD: readpassphrase.c,v 1.27 2019/01/25 00:19:25 millert Exp $    */

/*
 * Copyright (c) 2000-2002, 2007, 2010
 *    Todd C. Miller <millert@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * Sponsored in part by the Defense Advanced Research Projects
 * Agency (DARPA) and Air Force Research Laboratory, Air Force
 * Materiel Command, USAF, under agreement number F39502-99-1-0512.
 */

#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <paths.h>
#include <pwd.h>
#include <signal.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>
#include <readpassphrase.h>

#ifndef TCSASOFT
/* If we don't have TCSASOFT define it so that ORing it it below is a no-op. */
# define TCSASOFT 0
#endif

/* SunOS 4.x which lacks _POSIX_VDISABLE, but has VDISABLE */
#if !defined(_POSIX_VDISABLE) && defined(VDISABLE)
#  define _POSIX_VDISABLE       VDISABLE
#endif

static volatile sig_atomic_t signo[_NSIG];

static void handler(int);

char *
readpassphrase(const char *prompt, char *buf, size_t bufsiz, int flags)
{
    ssize_t nr;
    int input, output, save_errno, i, need_restart;
    char ch, *p, *end;
    struct termios term, oterm;
    struct sigaction sa, savealrm, saveint, savehup, savequit, saveterm;
    struct sigaction savetstp, savettin, savettou, savepipe;

    /* I suppose we could alloc on demand in this case (XXX). */
    if (bufsiz == 0) {
        errno = EINVAL;
        return(NULL);
    }

restart:
    for (i = 0; i < _NSIG; i++)
        signo[i] = 0;
    nr = -1;
    save_errno = 0;
    need_restart = 0;
    /*
     * Read and write to /dev/tty if available.  If not, read from
     * stdin and write to stderr unless a tty is required.
     */
    if ((flags & RPP_STDIN) ||
        (input = output = open(_PATH_TTY, O_RDWR)) == -1) {
        if (flags & RPP_REQUIRE_TTY) {
            errno = ENOTTY;
            return(NULL);
        }
        input = STDIN_FILENO;
        output = STDERR_FILENO;
    }

    /*
     * Turn off echo if possible.
     * If we are using a tty but are not the foreground pgrp this will
     * generate SIGTTOU, so do it *before* installing the signal handlers.
     */
    if (input != STDIN_FILENO && tcgetattr(input, &oterm) == 0) {
        memcpy(&term, &oterm, sizeof(term));
        if (!(flags & RPP_ECHO_ON))
            term.c_lflag &= ~(ECHO | ECHONL);
        (void)tcsetattr(input, TCSAFLUSH|TCSASOFT, &term);
    } else {
        memset(&term, 0, sizeof(term));
        term.c_lflag |= ECHO;
        memset(&oterm, 0, sizeof(oterm));
        oterm.c_lflag |= ECHO;
    }

    /*
     * Catch signals that would otherwise cause the user to end
     * up with echo turned off in the shell.  Don't worry about
     * things like SIGXCPU and SIGVTALRM for now.
     */
    sigemptyset(&sa.sa_mask);
    sa.sa_flags = 0;        /* don't restart system calls */
    sa.sa_handler = handler;
    (void)sigaction(SIGALRM, &sa, &savealrm);
    (void)sigaction(SIGHUP, &sa, &savehup);
    (void)sigaction(SIGINT, &sa, &saveint);
    (void)sigaction(SIGPIPE, &sa, &savepipe);
    (void)sigaction(SIGQUIT, &sa, &savequit);
    (void)sigaction(SIGTERM, &sa, &saveterm);
    (void)sigaction(SIGTSTP, &sa, &savetstp);
    (void)sigaction(SIGTTIN, &sa, &savettin);
    (void)sigaction(SIGTTOU, &sa, &savettou);

    if (!(flags & RPP_STDIN))
        (void)write(output, prompt, strlen(prompt));
    end = buf + bufsiz - 1;
    p = buf;
    while ((nr = read(input, &ch, 1)) == 1 && ch != '\n' && ch != '\r') {
        if (p < end) {
            if ((flags & RPP_SEVENBIT))
                ch &= 0x7f;
            if (isalpha((unsigned char)ch)) {
                if ((flags & RPP_FORCELOWER))
                    ch = (char)tolower((unsigned char)ch);
                if ((flags & RPP_FORCEUPPER))
                    ch = (char)toupper((unsigned char)ch);
            }
            *p++ = ch;
        }
    }
    *p = '\0';
    save_errno = errno;
    if (!(term.c_lflag & ECHO))
        (void)write(output, "\n", 1);

    /* Restore old terminal settings and signals. */
    if (memcmp(&term, &oterm, sizeof(term)) != 0) {
        const int sigttou = signo[SIGTTOU];

        /* Ignore SIGTTOU generated when we are not the fg pgrp. */
        while (tcsetattr(input, TCSAFLUSH|TCSASOFT, &oterm) == -1 &&
            errno == EINTR && !signo[SIGTTOU])
            continue;
        signo[SIGTTOU] = sigttou;
    }
    (void)sigaction(SIGALRM, &savealrm, NULL);
    (void)sigaction(SIGHUP, &savehup, NULL);
    (void)sigaction(SIGINT, &saveint, NULL);
    (void)sigaction(SIGQUIT, &savequit, NULL);
    (void)sigaction(SIGPIPE, &savepipe, NULL);
    (void)sigaction(SIGTERM, &saveterm, NULL);
    (void)sigaction(SIGTSTP, &savetstp, NULL);
    (void)sigaction(SIGTTIN, &savettin, NULL);
    (void)sigaction(SIGTTOU, &savettou, NULL);
    if (input != STDIN_FILENO)
        (void)close(input);

    /*
     * If we were interrupted by a signal, resend it to ourselves
     * now that we have restored the signal handlers.
     */
    for (i = 0; i < _NSIG; i++) {
        if (signo[i]) {
            kill(getpid(), i);
            switch (i) {
            case SIGTSTP:
            case SIGTTIN:
            case SIGTTOU:
                need_restart = 1;
            }
        }
    }
    if (need_restart)
        goto restart;

    if (save_errno)
        errno = save_errno;
    return(nr == -1 ? NULL : buf);
}


static void handler(int s)
{

    signo[s] = 1;
}