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https://github.com/gryf/mkinitramfs.git
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Added askpass sources
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418
askpass.c
Normal file
418
askpass.c
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/*
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* askpass.c - prompts a user for a passphrase using any suitable method
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* and prints the result to stdout.
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*
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* Copyright (C) 2008 David Härdeman <david@hardeman.nu>
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*
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* This package is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This package is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this package; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* 2012 - Piotr Karbowski <piotr.karbowski@gmail.com>
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* * Dropped splasy code.
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*/
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#define _GNU_SOURCE
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#define _BSD_SOURCE
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#define _POSIX_C_SOURCE 1
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#include <stdio.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <stdarg.h>
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#include <stdlib.h>
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#include <errno.h>
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#include <stdbool.h>
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#include <string.h>
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#include <termios.h>
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#include <sys/klog.h>
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#include <sys/select.h>
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#include <sys/ioctl.h>
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#include <signal.h>
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#include <dirent.h>
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#include <linux/vt.h>
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#include <sys/un.h>
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#include <sys/uio.h>
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#define DEBUG 0
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#define ARRAY_SIZE(x) (sizeof(x)/sizeof(x[0]))
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static bool disable_method(const char *method);
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/*****************************************************************************
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* Utility functions *
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*****************************************************************************/
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static void
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debug(const char *fmt, ...)
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{
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va_list ap;
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static bool first = true;
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static FILE *dbgfile;
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if (!DEBUG)
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return;
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if (first) {
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first = false;
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dbgfile = fopen("/tmp/askpass.debug", "a");
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}
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if (!dbgfile)
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return;
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va_start(ap, fmt);
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vfprintf(dbgfile, fmt, ap);
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va_end(ap);
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}
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static void
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usage(const char *arg0, const char *errmsg)
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{
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if (errmsg)
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fprintf(stderr, "Error: %s\nUsage: %s PROMPT\n", errmsg, arg0);
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else
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fprintf(stderr, "Usage: %s PROMPT\n", arg0);
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exit(EXIT_FAILURE);
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}
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static void
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fifo_common_finish(int fd, char **buf, size_t *used, size_t *size)
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{
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if (fd >= 0)
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close(fd);
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if (!*buf)
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return;
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memset(*buf, '\0', *size);
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free(*buf);
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*buf = NULL;
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*used = 0;
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*size = 0;
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}
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static bool
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fifo_common_read(int fd, char **buf, size_t *used, size_t *size)
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{
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ssize_t result;
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again:
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if ((*size - *used) == 0) {
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*size += 4096;
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*buf = realloc(*buf, *size);
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if (!*buf) {
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*size = 0;
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*used = 0;
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debug("Failed to allocate memory for passphrase\n");
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return false;
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}
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}
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reread:
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result = read(fd, *buf + *used, *size - *used);
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if (result < 0) {
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if (errno == EAGAIN)
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return false;
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if (errno == EINTR)
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goto reread;
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debug("Error when reading from fifo\n");
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return false;
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}
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debug("Read %i bytes from fifo\n", (int)result);
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*used += result;
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if (result == 0)
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return true;
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goto again;
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}
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/*****************************************************************************
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* fifo functions *
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*****************************************************************************/
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#define FIFO_PATH "/luks_passfifo"
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static size_t fifoused = 0;
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static size_t fifosize = 0;
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static char *fifobuf = NULL;
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static void
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fifo_finish(int fd)
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{
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fifo_common_finish(fd, &fifobuf, &fifoused, &fifosize);
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}
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static bool
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fifo_read(int fd, char **buf, size_t *size)
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{
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debug("In fifo_read\n");
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if (fifo_common_read(fd, &fifobuf, &fifoused, &fifosize)) {
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*buf = fifobuf;
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*size = fifoused;
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return true;
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}
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return false;
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}
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static int
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fifo_prepare(const char *prompt)
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{
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int ret;
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ret = mkfifo(FIFO_PATH, 0600);
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if (ret && errno != EEXIST)
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return -1;
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return open(FIFO_PATH, O_RDONLY | O_NONBLOCK);
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}
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/*****************************************************************************
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* console functions *
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*****************************************************************************/
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#define CONSOLE_PATH "/dev/console"
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static struct termios term_old;
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static bool term_set = false;
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static char *consolebuf = NULL;
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static size_t consolebuflen = 0;
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static void
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console_finish(int fd)
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{
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if (consolebuf) {
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memset(consolebuf, '\0', consolebuflen);
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free(consolebuf);
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consolebuf = NULL;
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consolebuflen = 0;
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}
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if (!term_set || fd < 0)
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return;
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term_set = false;
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tcsetattr(fd, TCSAFLUSH, &term_old);
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fprintf(stderr, "\n");
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klogctl(7, NULL, 0);
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}
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bool
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console_read(int fd, char **buf, size_t *size)
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{
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ssize_t nread;
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/* Console is in ICANON mode so we'll get entire lines */
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nread = getline(&consolebuf, &consolebuflen, stdin);
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if (nread < 0)
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return NULL;
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/* Strip trailing newline, if any */
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if (nread > 0 && consolebuf[nread - 1] == '\n') {
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nread--;
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consolebuf[nread] = '\0';
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}
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*size = nread;
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*buf = consolebuf;
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return true;
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}
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static int
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console_prepare(const char *prompt)
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{
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struct termios term_new;
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char *prompt_ptr = prompt;
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char *newline = NULL;
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if (!isatty(STDIN_FILENO)) {
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if (access(CONSOLE_PATH, R_OK | W_OK)) {
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debug("No access to console device " CONSOLE_PATH "\n");
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return -1;
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}
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if (!freopen(CONSOLE_PATH, "r", stdin) ||
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!freopen(CONSOLE_PATH, "a", stdout) ||
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!freopen(CONSOLE_PATH, "a", stderr) ||
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!isatty(STDIN_FILENO)) {
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debug("Failed to open console\n");
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return -1;
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}
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}
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if (tcgetattr(STDIN_FILENO, &term_old)) {
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debug("Failed to get terminal settings\n");
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return -1;
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}
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term_new = term_old;
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term_new.c_lflag &= ~ECHO;
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term_new.c_lflag |= ICANON;
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if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &term_new)) {
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debug("Failed to disable echoing\n");
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return -1;
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}
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/* handle any non-literal embedded newlines in prompt */
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while ( (newline = strstr(prompt_ptr,"\\n")) != NULL ) {
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/* Calculate length of string leading up to newline. */
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int line_len = newline - prompt_ptr;
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/* Force trimming of prompt to location of newline. */
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if (fwrite(prompt_ptr, line_len, 1, stderr) < 1 ||
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fwrite("\n", 1, 1, stderr) < 1) {
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debug("Failed to print prompt\n");
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tcsetattr(STDIN_FILENO, TCSAFLUSH, &term_old);
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return -1;
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}
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/* Skip over newline. */
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prompt_ptr = newline + 2;
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}
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if (fputs(prompt_ptr, stderr) < 0) {
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debug("Failed to print prompt\n");
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tcsetattr(STDIN_FILENO, TCSAFLUSH, &term_old);
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return -1;
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}
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/* Disable printk to console */
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klogctl(6, NULL, 0);
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term_set = true;
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return STDIN_FILENO;
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}
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/*****************************************************************************
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* main functions *
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*****************************************************************************/
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struct method {
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const char *name;
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int (*prepare)(const char *prompt);
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bool (*read)(int fd, char **buf, size_t *size);
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void (*finish)(int fd);
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bool active;
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bool enabled;
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int fd;
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};
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static struct method methods[] = {
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{ "fifo", fifo_prepare, fifo_read, fifo_finish, false, true, -1 },
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{ "console", console_prepare, console_read, console_finish, false, true, -1 }
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};
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static bool
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disable_method(const char *method)
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{
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int i;
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bool result = false;
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debug("Disabling method %s\n", method ? method : "ALL");
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for (i = 0; i < ARRAY_SIZE(methods); i++) {
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/* A NULL method means all methods should be disabled */
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if (method && strcmp(methods[i].name, method))
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continue;
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if (!methods[i].enabled)
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continue;
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if (methods[i].active)
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methods[i].finish(methods[i].fd);
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methods[i].active = false;
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methods[i].fd = -1;
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methods[i].enabled = false;
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result = true;
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}
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return result;
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}
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int
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main(int argc, char **argv, char **envp)
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{
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char *pass = NULL;
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size_t passlen = 0;
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int i;
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int nfds;
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fd_set fds;
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int ret;
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bool done = false;
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sigset_t sigset;
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if (argc != 2)
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usage(argv[0], "incorrect number of arguments");
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sigfillset(&sigset);
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sigprocmask(SIG_BLOCK, &sigset, NULL);
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for (i = 0; i < ARRAY_SIZE(methods); i++) {
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if (!methods[i].enabled)
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continue;
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debug("Enabling method %s\n", methods[i].name);
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methods[i].fd = methods[i].prepare(argv[1]);
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if (methods[i].fd < 0)
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methods[i].active = false;
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else
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methods[i].active = true;
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}
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while (!done) {
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nfds = 0;
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FD_ZERO(&fds);
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for (i = 0; i < ARRAY_SIZE(methods); i++) {
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if (!methods[i].enabled || methods[i].fd < 0)
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continue;
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debug("method %i has fd %i and name %s\n", i, methods[i].fd, methods[i].name);
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FD_SET(methods[i].fd, &fds);
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if (methods[i].fd + 1 > nfds)
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nfds = methods[i].fd + 1;
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}
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if (nfds == 0) {
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debug("All methods disabled\n");
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exit(EXIT_FAILURE);
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}
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debug("Starting select with nfds %i\n", nfds);
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ret = select(nfds, &fds, NULL, NULL, NULL);
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if (ret <= 0) {
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if (ret == 0 || errno == EINTR)
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continue;
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debug("Select failed\n");
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disable_method(NULL);
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exit(EXIT_FAILURE);
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}
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for (i = 0; i < ARRAY_SIZE(methods); i++) {
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if (!methods[i].enabled || methods[i].fd < 0)
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continue;
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if (!FD_ISSET(methods[i].fd, &fds))
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continue;
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if (methods[i].read(methods[i].fd, &pass, &passlen) && pass) {
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done = true;
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break;
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}
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}
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}
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debug("Writing %i bytes to stdout\n", (int)passlen);
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write(STDOUT_FILENO, pass, passlen);
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disable_method(NULL);
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exit(EXIT_SUCCESS);
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}
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