dcf6602daa
now pass command status change info back via the socketpair. This allows the parent to distinguish between signals it has been sent directly and signals the command has received. It also means the parent can once again print the signal notifications to the tty so all writes to the pty master occur in the parent. The command is now always started in background mode with tty signals handled by the parent.
286 lines
6.8 KiB
C
286 lines
6.8 KiB
C
/*
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* Copyright (c) 1996, 1998-2005, 2007-2009
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* Todd C. Miller <Todd.Miller@courtesan.com>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* Sponsored in part by the Defense Advanced Research Projects
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* Agency (DARPA) and Air Force Research Laboratory, Air Force
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* Materiel Command, USAF, under agreement number F39502-99-1-0512.
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*/
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#ifdef __TANDEM
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# include <floss.h>
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#endif
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#include <config.h>
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#include <sys/types.h>
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#include <sys/param.h>
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#include <stdio.h>
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#ifdef STDC_HEADERS
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# include <stdlib.h>
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# include <stddef.h>
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#else
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# ifdef HAVE_STDLIB_H
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# include <stdlib.h>
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# endif
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#endif /* STDC_HEADERS */
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#ifdef HAVE_STRING_H
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# if defined(HAVE_MEMORY_H) && !defined(STDC_HEADERS)
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# include <memory.h>
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# endif
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# include <string.h>
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#else
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# ifdef HAVE_STRINGS_H
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# include <strings.h>
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# endif
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#endif /* HAVE_STRING_H */
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#ifdef HAVE_UNISTD_H
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# include <unistd.h>
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#endif /* HAVE_UNISTD_H */
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#include <pwd.h>
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#include <errno.h>
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#include <signal.h>
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#include <fcntl.h>
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#include "sudo.h"
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#ifndef lint
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__unused static const char rcsid[] = "$Sudo$";
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#endif /* lint */
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static volatile sig_atomic_t signo;
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static void handler __P((int));
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static char *getln __P((int, char *, size_t, int));
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static char *sudo_askpass __P((const char *));
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/*
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* Like getpass(3) but with timeout and echo flags.
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*/
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char *
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tgetpass(prompt, timeout, flags)
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const char *prompt;
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int timeout;
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int flags;
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{
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sigaction_t sa, savealrm, saveint, savehup, savequit, saveterm;
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sigaction_t savetstp, savettin, savettou;
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char *pass;
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static char buf[SUDO_PASS_MAX + 1];
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int input, output, save_errno, neednl;;
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(void) fflush(stdout);
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/* If using a helper program to get the password, run it instead. */
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if (ISSET(flags, TGP_ASKPASS) && user_askpass)
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return(sudo_askpass(prompt));
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restart:
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signo = 0;
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pass = NULL;
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save_errno = 0;
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/* Open /dev/tty for reading/writing if possible else use stdin/stderr. */
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if (ISSET(flags, TGP_STDIN) ||
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(input = output = open(_PATH_TTY, O_RDWR|O_NOCTTY)) == -1) {
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input = STDIN_FILENO;
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output = STDERR_FILENO;
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}
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/*
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* Catch signals that would otherwise cause the user to end
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* up with echo turned off in the shell.
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*/
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zero_bytes(&sa, sizeof(sa));
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sigemptyset(&sa.sa_mask);
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sa.sa_flags = SA_INTERRUPT; /* don't restart system calls */
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sa.sa_handler = handler;
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(void) sigaction(SIGALRM, &sa, &savealrm);
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(void) sigaction(SIGINT, &sa, &saveint);
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(void) sigaction(SIGHUP, &sa, &savehup);
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(void) sigaction(SIGQUIT, &sa, &savequit);
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(void) sigaction(SIGTERM, &sa, &saveterm);
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(void) sigaction(SIGTSTP, &sa, &savetstp);
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(void) sigaction(SIGTTIN, &sa, &savettin);
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(void) sigaction(SIGTTOU, &sa, &savettou);
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if (def_pwfeedback)
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neednl = term_cbreak(input);
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else
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neednl = term_noecho(input);
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/* No output if we are already backgrounded. */
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if (signo != SIGTTOU && signo != SIGTTIN) {
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if (prompt)
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(void) write(output, prompt, strlen(prompt));
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if (timeout > 0)
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alarm(timeout);
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pass = getln(input, buf, sizeof(buf), def_pwfeedback);
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alarm(0);
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save_errno = errno;
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if (neednl)
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(void) write(output, "\n", 1);
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}
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/* Restore old tty settings and signals. */
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term_restore(input, 1);
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(void) sigaction(SIGALRM, &savealrm, NULL);
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(void) sigaction(SIGINT, &saveint, NULL);
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(void) sigaction(SIGHUP, &savehup, NULL);
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(void) sigaction(SIGQUIT, &savequit, NULL);
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(void) sigaction(SIGTERM, &saveterm, NULL);
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(void) sigaction(SIGTSTP, &savetstp, NULL);
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(void) sigaction(SIGTTIN, &savettin, NULL);
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(void) sigaction(SIGTTOU, &savettou, NULL);
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if (input != STDIN_FILENO)
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(void) close(input);
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/*
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* If we were interrupted by a signal, resend it to ourselves
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* now that we have restored the signal handlers.
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*/
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if (signo) {
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kill(getpid(), signo);
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switch (signo) {
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case SIGTSTP:
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case SIGTTIN:
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case SIGTTOU:
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goto restart;
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}
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}
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if (save_errno)
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errno = save_errno;
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return(pass);
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}
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/*
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* Fork a child and exec sudo-askpass to get the password from the user.
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*/
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static char *
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sudo_askpass(prompt)
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const char *prompt;
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{
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static char buf[SUDO_PASS_MAX + 1], *pass;
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sigaction_t sa, saved_sa_pipe;
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int pfd[2];
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pid_t pid;
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if (pipe(pfd) == -1)
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error(1, "unable to create pipe");
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if ((pid = fork()) == -1)
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error(1, "unable to fork");
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if (pid == 0) {
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/* child, point stdout to output side of the pipe and exec askpass */
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(void) dup2(pfd[1], STDOUT_FILENO);
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set_perms(PERM_FULL_USER);
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closefrom(STDERR_FILENO + 1);
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execl(user_askpass, user_askpass, prompt, (char *)NULL);
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warning("unable to run %s", user_askpass);
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_exit(255);
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}
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/* Ignore SIGPIPE in case child exits prematurely */
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zero_bytes(&sa, sizeof(sa));
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sigemptyset(&sa.sa_mask);
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sa.sa_flags = 0;
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sa.sa_handler = SIG_IGN;
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(void) sigaction(SIGPIPE, &sa, &saved_sa_pipe);
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/* Get response from child (askpass) and restore SIGPIPE handler */
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(void) close(pfd[1]);
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pass = getln(pfd[0], buf, sizeof(buf), 0);
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(void) close(pfd[0]);
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(void) sigaction(SIGPIPE, &saved_sa_pipe, NULL);
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return(pass);
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}
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extern int term_erase, term_kill;
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static char *
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getln(fd, buf, bufsiz, feedback)
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int fd;
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char *buf;
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size_t bufsiz;
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int feedback;
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{
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size_t left = bufsiz;
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ssize_t nr = -1;
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char *cp = buf;
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char c = '\0';
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if (left == 0) {
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errno = EINVAL;
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return(NULL); /* sanity */
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}
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while (--left) {
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nr = read(fd, &c, 1);
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if (nr != 1 || c == '\n' || c == '\r')
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break;
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if (feedback) {
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if (c == term_kill) {
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while (cp > buf) {
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(void) write(fd, "\b \b", 3);
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--cp;
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}
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left = bufsiz;
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continue;
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} else if (c == term_erase) {
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if (cp > buf) {
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(void) write(fd, "\b \b", 3);
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--cp;
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left++;
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}
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continue;
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}
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(void) write(fd, "*", 1);
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}
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*cp++ = c;
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}
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*cp = '\0';
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if (feedback) {
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/* erase stars */
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while (cp > buf) {
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(void) write(fd, "\b \b", 3);
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--cp;
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}
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}
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return(nr == 1 ? buf : NULL);
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}
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static void
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handler(s)
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int s;
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{
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if (s != SIGALRM)
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signo = s;
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}
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int
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tty_present()
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{
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int fd;
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if ((fd = open(_PATH_TTY, O_RDWR|O_NOCTTY)) != -1)
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close(fd);
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return(fd != -1);
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}
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