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* Password-prompt - Read a password from the terminal and print it
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* Copyright © 2008-2018 Teddy Hogeborn
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* Copyright © 2008-2018 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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* Copyright © 2008-2010 Teddy Hogeborn
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* Copyright © 2008-2010 Björn Påhlsson
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* This program is free software: you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation, either version 3 of the
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* License, or (at your option) any later version.
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* This program 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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* along with this program. If not, see
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* <http://www.gnu.org/licenses/>.
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* Contact the authors at <mandos@recompile.se>.
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* Contact the authors at <mandos@fukt.bsnet.se>.
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#define _GNU_SOURCE /* getline(), asprintf() */
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#include <termios.h> /* struct termios, tcsetattr(),
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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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getenv(), free() */
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#include <dirent.h> /* scandir(), alphasort() */
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#include <stdio.h> /* fprintf(), stderr, getline(),
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stdin, feof(), fputc(), vfprintf(),
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stdin, feof(), fputc()
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#include <errno.h> /* errno, EBADF, ENOTTY, EINVAL,
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EFAULT, EFBIG, EIO, ENOSPC, EINTR
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#include <iso646.h> /* or, not */
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#include <stdbool.h> /* bool, false, true */
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#include <inttypes.h> /* strtoumax() */
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#include <sys/stat.h> /* struct stat, lstat(), open() */
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#include <string.h> /* strlen, rindex, memcmp, strerror()
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#include <sys/stat.h> /* struct stat, lstat(), open() */
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#include <string.h> /* strlen, rindex, memcmp */
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#include <argp.h> /* struct argp_option, struct
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argp_state, struct argp,
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argp_parse(), error_t,
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#include <sysexits.h> /* EX_SOFTWARE, EX_OSERR,
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EX_UNAVAILABLE, EX_IOERR, EX_OK */
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#include <fcntl.h> /* open() */
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#include <stdarg.h> /* va_list, va_start(), ... */
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volatile sig_atomic_t quit_now = 0;
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int signal_received;
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bool debug = false;
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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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const char *argp_program_bug_address = "<mandos@fukt.bsnet.se>";
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/* Needed for conflic resolution */
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const char plymouthd_name[] = "plymouthd";
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static void termination_handler(int signum){
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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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__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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maxvalue = 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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or maxvalue != (uintmax_t)((pid_t)maxvalue)){
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char *cmdline_filename;
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ret = asprintf(&cmdline_filename, "/proc/%s/cmdline",
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ret = asprintf(&cmdline_filename, "/proc/%s/cmdline", proc_entry->d_name);
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error_plus(0, errno, "asprintf");
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error(0, errno, "asprintf");
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/* Open /proc/<pid>/cmdline */
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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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error(0, errno, "open");
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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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error(0, errno, "realloc");
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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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error(0, errno, "read");
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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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if(strcmp(cmdline_base, plymouthd_name) != 0){
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fprintf(stderr, "\"%s\" equals \"%s\"\n", cmdline_base,
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struct dirent **direntries = NULL;
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struct dirent **direntries;
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ret = scandir("/proc", &direntries, is_plymouth, alphasort);
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error_plus(1, errno, "scandir");
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error(1, errno, "scandir");
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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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fprintf(stderr, "Starting %s\n", argv[0]);
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if(conflict_detection()){
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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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fprintf(stderr, "Stopping %s because of conflict", argv[0]);
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return EXIT_FAILURE;
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if(tcgetattr(STDIN_FILENO, &t_old) != 0){
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error_plus(0, errno, "tcgetattr");
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error(0, errno, "tcgetattr");
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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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error(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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error(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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error(0, errno, "sigaddset");
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/* Need to check if the handler is SIG_IGN before handling:
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ret = sigaction(SIGINT, NULL, &old_action);
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error_plus(0, errno, "sigaction");
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error(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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error(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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error(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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error(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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error(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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error(0, errno, "sigaction");
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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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error(0, errno, "tcsetattr-echo");
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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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error(0, errno, "write");
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sret = close(STDOUT_FILENO);
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error_plus(0, errno, "close");
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error(0, errno, "close");
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status = EX_OSFILE;
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if(errno != EINTR and not feof(stdin)){
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error_plus(0, errno, "getline");
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error(0, errno, "getline");
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status = EX_UNAVAILABLE;
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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(sret == 0), then the only sensible thing to do is to retry to
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fputc('\n', stderr);
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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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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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error(0, errno, "tcsetattr+echo");
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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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error(0, errno, "sigaction");
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raise(signal_received);