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/* -*- coding: utf-8; mode: c; mode: orgtbl -*- */
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* Password-prompt - Read a password from the terminal and print it
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* Copyright © 2008-2019, 2021-2022 Teddy Hogeborn
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* Copyright © 2008-2019, 2021-2022 Björn Påhlsson
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* This file is part of Mandos.
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* Mandos is free software: you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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* Mandos is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with Mandos. If not, see <http://www.gnu.org/licenses/>.
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* Contact the authors at <mandos@recompile.se>.
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#define _GNU_SOURCE /* vasprintf(),
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program_invocation_short_name,
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asprintf(), getline() */
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#include <sys/types.h> /* sig_atomic_t, pid_t */
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#define _GNU_SOURCE /* getline() */
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#define _FORTIFY_SOURCE 2
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#include <termios.h> /* struct termios, tcsetattr(),
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TCSAFLUSH, tcgetattr(), ECHO */
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#include <unistd.h> /* struct termios, tcsetattr(),
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STDIN_FILENO, TCSAFLUSH,
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#include <signal.h> /* sig_atomic_t, raise(), struct
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sigaction, sigemptyset(),
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sigaction(), sigaddset(), SIGINT,
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SIGQUIT, SIGHUP, SIGTERM */
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#include <stddef.h> /* NULL, size_t */
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#include <sys/types.h> /* ssize_t */
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#include <stdlib.h> /* EXIT_SUCCESS, EXIT_FAILURE */
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#include <stdio.h> /* fprintf(), stderr, getline(),
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stdin, feof(), perror(), fputc(),
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#include <errno.h> /* errno, EINVAL */
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#include <iso646.h> /* or, not */
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#include <stdbool.h> /* bool, false, true */
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#include <argp.h> /* argp_program_version,
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argp_program_bug_address,
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struct argp_state, argp_state_help,
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ARGP_HELP_EXIT_OK, ARGP_HELP_USAGE,
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ARGP_ERR_UNKNOWN, argp_parse(),
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ARGP_IN_ORDER, ARGP_NO_HELP */
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#include <stdarg.h> /* va_list, va_start(), vfprintf() */
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#include <stdio.h> /* vasprintf(), fprintf(), stderr,
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vfprintf(), asprintf(), getline(),
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stdin, feof(), clearerr(),
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#include <errno.h> /* program_invocation_short_name,
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errno, ENOENT, error_t, ENOMEM,
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EINVAL, EBADF, ENOTTY, EFAULT,
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EFBIG, EIO, ENOSPC, EINTR */
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#include <string.h> /* strerror(), strrchr(), strcmp() */
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#include <error.h> /* error() */
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#include <stdlib.h> /* free(), realloc(), EXIT_SUCCESS,
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EXIT_FAILURE, getenv() */
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#include <unistd.h> /* access(), R_OK, ssize_t, close(),
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read(), STDIN_FILENO, write(),
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#include <dirent.h> /* struct dirent, scandir(),
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#include <inttypes.h> /* uintmax_t, strtoumax() */
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#include <iso646.h> /* or, and, not */
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#include <fcntl.h> /* open(), O_RDONLY */
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#include <stddef.h> /* NULL, size_t */
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#include <termios.h> /* struct termios, tcgetattr(),
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tcflag_t, ECHO, tcsetattr(),
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#include <signal.h> /* struct sigaction, sigemptyset(),
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sigaddset(), SIGINT, SIGHUP,
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SIGTERM, SIG_IGN, SIG_DFL,
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#include <sysexits.h> /* EX_OSERR, EX_USAGE, EX_UNAVAILABLE,
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EX_IOERR, EX_OSFILE, EX_OK */
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volatile sig_atomic_t quit_now = 0;
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const char *argp_program_version = "password-prompt " VERSION;
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const char *argp_program_bug_address = "<mandos@recompile.se>";
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/* Needed for conflict resolution */
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const char plymouth_name[] = "plymouthd";
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/* Function to use when printing errors */
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__attribute__((format (gnu_printf, 3, 4)))
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void error_plus(int status, int errnum, const char *formatstring,
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va_start(ap, formatstring);
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ret = vasprintf(&text, formatstring, ap);
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fprintf(stderr, "Mandos plugin %s: ",
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program_invocation_short_name);
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vfprintf(stderr, formatstring, ap);
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fprintf(stderr, ": %s\n", strerror(errnum));
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error(status, errno, "vasprintf while printing error");
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fprintf(stderr, "Mandos plugin ");
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error(status, errnum, "%s", text);
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static void termination_handler(int signum){
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signal_received = signum;
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bool conflict_detection(void){
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/* plymouth conflicts with password-prompt since both want to read
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from the terminal. Password-prompt will exit if it detects
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plymouth since plymouth performs the same functionality.
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if(access("/run/plymouth/pid", R_OK) == 0){
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__attribute__((nonnull))
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int is_plymouth(const struct dirent *proc_entry){
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proc_id = strtoumax(proc_entry->d_name, &tmp, 10);
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if(errno != 0 or *tmp != '\0'
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or proc_id != (uintmax_t)((pid_t)proc_id)){
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char *cmdline_filename;
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ret = asprintf(&cmdline_filename, "/proc/%s/cmdline",
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error_plus(0, errno, "asprintf");
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/* Open /proc/<pid>/cmdline */
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cl_fd = open(cmdline_filename, O_RDONLY);
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free(cmdline_filename);
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error_plus(0, errno, "open");
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char *cmdline = NULL;
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size_t cmdline_len = 0;
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size_t cmdline_allocated = 0;
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const size_t blocksize = 1024;
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/* Allocate more space? */
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if(cmdline_len + blocksize + 1 > cmdline_allocated){
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tmp = realloc(cmdline, cmdline_allocated + blocksize + 1);
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error_plus(0, errno, "realloc");
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cmdline_allocated += blocksize;
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sret = read(cl_fd, cmdline + cmdline_len,
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cmdline_allocated - cmdline_len);
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error_plus(0, errno, "read");
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cmdline_len += (size_t)sret;
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error_plus(0, errno, "close");
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cmdline[cmdline_len] = '\0'; /* Make sure it is terminated */
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/* we now have cmdline */
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char *cmdline_base = strrchr(cmdline, '/');
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if(cmdline_base != NULL){
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cmdline_base += 1; /* skip the slash */
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cmdline_base = cmdline;
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if(strcmp(cmdline_base, plymouth_name) != 0){
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fprintf(stderr, "\"%s\" is not \"%s\"\n", cmdline_base,
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fprintf(stderr, "\"%s\" equals \"%s\"\n", cmdline_base,
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struct dirent **direntries = NULL;
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ret = scandir("/proc", &direntries, is_plymouth, alphasort);
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error_plus(1, errno, "scandir");
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volatile bool quit_now = false;
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void termination_handler(int signum){
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int main(int argc, char **argv){
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struct termios t_new, t_old;
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char *buffer = NULL;
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int status = EXIT_SUCCESS;
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struct sigaction old_action,
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new_action = { .sa_handler = termination_handler,
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struct argp_option options[] = {
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{ .name = "prefix", .key = 'p',
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.arg = "PREFIX", .flags = 0,
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.doc = "Prefix shown before the prompt", .group = 2 },
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{ .name = "prompt", .key = 129,
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.arg = "PROMPT", .flags = 0,
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.doc = "The prompt to show", .group = 2 },
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{ .name = "debug", .key = 128,
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.doc = "Debug mode", .group = 3 },
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* These reproduce what we would get without ARGP_NO_HELP
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{ .name = "help", .key = '?',
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.doc = "Give this help list", .group = -1 },
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{ .name = "usage", .key = -3,
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.doc = "Give a short usage message", .group = -1 },
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{ .name = "version", .key = 'V',
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.doc = "Print program version", .group = -1 },
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__attribute__((nonnull(3)))
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error_t parse_opt (int key, char *arg, struct argp_state *state){
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case 'p': /* --prefix */
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case 128: /* --debug */
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case 129: /* --prompt */
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* These reproduce what we would get without ARGP_NO_HELP
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case '?': /* --help */
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argp_state_help(state, state->out_stream,
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(ARGP_HELP_STD_HELP | ARGP_HELP_EXIT_ERR)
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& ~(unsigned int)ARGP_HELP_EXIT_OK);
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__builtin_unreachable();
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case -3: /* --usage */
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argp_state_help(state, state->out_stream,
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ARGP_HELP_USAGE | ARGP_HELP_EXIT_ERR);
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__builtin_unreachable();
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case 'V': /* --version */
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fprintf(state->out_stream, "%s\n", argp_program_version);
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exit(argp_err_exit_status);
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return ARGP_ERR_UNKNOWN;
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struct argp argp = { .options = options, .parser = parse_opt,
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.doc = "Mandos password-prompt -- Read and"
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" output a password" };
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ret = argp_parse(&argp, argc, argv,
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ARGP_IN_ORDER | ARGP_NO_HELP, NULL, NULL);
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error_plus(0, errno, "argp_parse");
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fprintf(stderr, "Starting %s\n", argv[0]);
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if(conflict_detection()){
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fprintf(stderr, "Stopping %s because of conflict\n", argv[0]);
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if (tcgetattr(STDIN_FILENO, &t_old) != 0){
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return EXIT_FAILURE;
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fprintf(stderr, "Storing current terminal attributes\n");
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if(tcgetattr(STDIN_FILENO, &t_old) != 0){
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error_plus(0, errno, "tcgetattr");
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return EX_UNAVAILABLE;
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sigemptyset(&new_action.sa_mask);
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ret = sigaddset(&new_action.sa_mask, SIGINT);
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error_plus(0, errno, "sigaddset");
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ret = sigaddset(&new_action.sa_mask, SIGHUP);
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error_plus(0, errno, "sigaddset");
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ret = sigaddset(&new_action.sa_mask, SIGTERM);
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error_plus(0, errno, "sigaddset");
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/* Need to check if the handler is SIG_IGN before handling:
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| [[info:libc:Initial Signal Actions]] |
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| [[info:libc:Basic Signal Handling]] |
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ret = sigaction(SIGINT, NULL, &old_action);
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error_plus(0, errno, "sigaction");
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if(old_action.sa_handler != SIG_IGN){
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ret = sigaction(SIGINT, &new_action, NULL);
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error_plus(0, errno, "sigaction");
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ret = sigaction(SIGHUP, NULL, &old_action);
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error_plus(0, errno, "sigaction");
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if(old_action.sa_handler != SIG_IGN){
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ret = sigaction(SIGHUP, &new_action, NULL);
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error_plus(0, errno, "sigaction");
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ret = sigaction(SIGTERM, NULL, &old_action);
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error_plus(0, errno, "sigaction");
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if(old_action.sa_handler != SIG_IGN){
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ret = sigaction(SIGTERM, &new_action, NULL);
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error_plus(0, errno, "sigaction");
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fprintf(stderr, "Removing echo flag from terminal attributes\n");
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sigaddset(&new_action.sa_mask, SIGINT);
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sigaddset(&new_action.sa_mask, SIGQUIT);
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sigaddset(&new_action.sa_mask, SIGHUP);
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sigaddset(&new_action.sa_mask, SIGTERM);
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sigaction(SIGINT, NULL, &old_action);
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if (old_action.sa_handler != SIG_IGN)
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sigaction(SIGINT, &new_action, NULL);
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sigaction(SIGQUIT, NULL, &old_action);
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if (old_action.sa_handler != SIG_IGN)
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sigaction(SIGQUIT, &new_action, NULL);
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sigaction(SIGHUP, NULL, &old_action);
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if (old_action.sa_handler != SIG_IGN)
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sigaction(SIGHUP, &new_action, NULL);
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sigaction(SIGTERM, NULL, &old_action);
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if (old_action.sa_handler != SIG_IGN)
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sigaction(SIGTERM, &new_action, NULL);
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t_new.c_lflag &= ~(tcflag_t)ECHO;
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if(tcsetattr(STDIN_FILENO, TCSAFLUSH, &t_new) != 0){
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error_plus(0, errno, "tcsetattr-echo");
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return EX_UNAVAILABLE;
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t_new.c_lflag &= ~ECHO;
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if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &t_new) != 0){
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perror("tcsetattr-echo");
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fprintf(stderr, "Waiting for input from stdin \n");
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fprintf(stderr, "Interrupted by signal, exiting.\n");
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status = EXIT_FAILURE;
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fprintf(stderr, "%s ", prefix);
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fprintf(stderr, "%s: ", prompt);
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const char *cryptsource = getenv("CRYPTTAB_SOURCE");
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const char *crypttarget = getenv("CRYPTTAB_NAME");
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/* Before cryptsetup 1.1.0~rc2 */
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if(cryptsource == NULL){
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cryptsource = getenv("cryptsource");
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if(crypttarget == NULL){
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crypttarget = getenv("crypttarget");
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const char *const prompt1 = "Unlocking the disk";
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const char *const prompt2 = "Enter passphrase";
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if(cryptsource == NULL){
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if(crypttarget == NULL){
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fprintf(stderr, "%s to unlock the disk: ", prompt2);
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fprintf(stderr, "%s (%s)\n%s: ", prompt1, crypttarget,
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if(crypttarget == NULL){
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fprintf(stderr, "%s %s\n%s: ", prompt1, cryptsource,
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fprintf(stderr, "%s %s (%s)\n%s: ", prompt1, cryptsource,
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crypttarget, prompt2);
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sret = getline(&buffer, &n, stdin);
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fprintf(stderr, "Password: ");
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ret = getline(&buffer, &n, stdin);
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fprintf(stdout, "%s", buffer);
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status = EXIT_SUCCESS;
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/* Make n = data size instead of allocated buffer size */
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/* Strip final newline */
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if(n > 0 and buffer[n-1] == '\n'){
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buffer[n-1] = '\0'; /* not strictly necessary */
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sret = write(STDOUT_FILENO, buffer + written, n - written);
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error_plus(0, errno, "write");
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status = EXIT_FAILURE;
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written += (size_t)sret;
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sret = close(STDOUT_FILENO);
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error_plus(0, errno, "close");
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error_plus(0, errno, "getline");
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status = EX_UNAVAILABLE;
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// ret == 0 makes no other sence than to retry to read from stdin
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if (errno != EINTR and not feof(stdin)){
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status = EXIT_FAILURE;
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/* if(sret == 0), then the only sensible thing to do is to retry
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to read from stdin */
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if(debug and not quit_now){
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/* If quit_now is nonzero, we were interrupted by a signal, and
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will print that later, so no need to show this too. */
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fprintf(stderr, "getline() returned 0, retrying.\n");
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fprintf(stderr, "Restoring terminal attributes\n");
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if(tcsetattr(STDIN_FILENO, TCSAFLUSH, &t_old) != 0){
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error_plus(0, errno, "tcsetattr+echo");
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sigemptyset(&old_action.sa_mask);
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old_action.sa_handler = SIG_DFL;
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ret = sigaction(signal_received, &old_action, NULL);
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error_plus(0, errno, "sigaction");
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raise(signal_received);
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fprintf(stderr, "%s is exiting with status %d\n", argv[0],
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if(status == EXIT_SUCCESS or status == EX_OK){
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if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &t_old) != 0){
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perror("tcsetattr+echo");
added
removed
plugins.d/passprompt.c
