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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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SIGQUIT, SIGHUP, SIGTERM,
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#include <stddef.h> /* NULL, size_t, ssize_t */
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#include <sys/types.h> /* ssize_t, struct dirent, pid_t, ssize_t */
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#include <sys/types.h> /* ssize_t, struct dirent, pid_t,
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#include <stdlib.h> /* EXIT_SUCCESS, EXIT_FAILURE,
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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()
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stdin, feof(), fputc(), vfprintf(), vasprintf()
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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() */
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#include <string.h> /* strlen, rindex, memcmp */
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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 <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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ARGP_ERR_UNKNOWN */
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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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const char *argp_program_version = "password-prompt " VERSION;
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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_path[] = "/sbin/plymouth";
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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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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: ", program_invocation_short_name);
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vfprintf(stderr, formatstring, ap);
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fprintf(stderr, ": ");
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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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bool conflict_detection(void){
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/* plymouth conflicts with password-promt since both want to control the
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associated terminal. Password-prompt exit since plymouth perferms the same
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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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int is_plymouth(const struct dirent *proc_entry){
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uintmax_t maxvalue;
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char exe_target[sizeof(plymouthd_path)];
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ret = asprintf(&exe_link, "/proc/%s/exe", proc_entry->d_name);
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char *cmdline_filename;
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ret = asprintf(&cmdline_filename, "/proc/%s/cmdline",
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error(0, errno, "asprintf");
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struct stat exe_stat;
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ret = lstat(exe_link, &exe_stat);
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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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if(errno != ENOENT){
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error(0, errno, "lstat");
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if(not S_ISLNK(exe_stat.st_mode)
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or exe_stat.st_uid != 0
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or exe_stat.st_gid != 0){
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ssize_t sret = readlink(exe_link, exe_target, sizeof(exe_target));
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if((sret != (ssize_t)sizeof(plymouthd_path)-1) or
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(memcmp(plymouthd_path, exe_target,
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sizeof(plymouthd_path)-1) != 0)){
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error(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(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(0, errno, "read");
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cmdline_len += (size_t)sret;
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error(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;
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ret = scandir("/proc", &direntries, is_plymouth, alphasort);
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error(1, errno, "scandir");