summaryrefslogtreecommitdiffstats
path: root/attacher.c
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--attacher.c1117
1 files changed, 1117 insertions, 0 deletions
diff --git a/attacher.c b/attacher.c
new file mode 100644
index 0000000..c35ae7a
--- /dev/null
+++ b/attacher.c
@@ -0,0 +1,1117 @@
+/* Copyright (c) 2008, 2009
+ * Juergen Weigert (jnweiger@immd4.informatik.uni-erlangen.de)
+ * Michael Schroeder (mlschroe@immd4.informatik.uni-erlangen.de)
+ * Micah Cowan (micah@cowan.name)
+ * Sadrul Habib Chowdhury (sadrul@users.sourceforge.net)
+ * Copyright (c) 1993-2002, 2003, 2005, 2006, 2007
+ * Juergen Weigert (jnweiger@immd4.informatik.uni-erlangen.de)
+ * Michael Schroeder (mlschroe@immd4.informatik.uni-erlangen.de)
+ * Copyright (c) 1987 Oliver Laumann
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program (see the file COPYING); if not, see
+ * https://www.gnu.org/licenses/, or contact Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02111-1301 USA
+ *
+ ****************************************************************
+ */
+
+#include "config.h"
+#include <stdbool.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <fcntl.h>
+#include <signal.h>
+#include "screen.h"
+#include "extern.h"
+
+#include <pwd.h>
+
+static int WriteMessage __P((int, struct msg *));
+static sigret_t AttacherSigInt __P(SIGPROTOARG);
+#if defined(SIGWINCH) && defined(TIOCGWINSZ)
+static sigret_t AttacherWinch __P(SIGPROTOARG);
+#endif
+#ifdef LOCK
+static sigret_t DoLock __P(SIGPROTOARG);
+static void LockTerminal __P((void));
+static sigret_t LockHup __P(SIGPROTOARG);
+static void screen_builtin_lck __P((void));
+#endif
+#ifdef DEBUG
+static sigret_t AttacherChld __P(SIGPROTOARG);
+#endif
+static sigret_t AttachSigCont __P(SIGPROTOARG);
+
+extern int real_uid, real_gid, eff_uid, eff_gid;
+extern int ServerSocket;
+extern struct display *displays;
+extern char *SockName, *SockMatch, SockPath[];
+extern char HostName[];
+extern struct passwd *ppp;
+extern char *attach_tty, *attach_term, *LoginName, *preselect;
+/* Indicator whether the current tty exists in another namespace. */
+extern bool attach_tty_is_in_new_ns;
+/* Content of the tty symlink when attach_tty_is_in_new_ns == true. */
+extern char attach_tty_name_in_ns[];
+extern int xflag, dflag, rflag, quietflag, adaptflag;
+extern struct mode attach_Mode;
+extern struct NewWindow nwin_options;
+extern int MasterPid, attach_fd;
+
+#ifdef MULTIUSER
+extern char *multi;
+extern int multiattach, multi_uid, own_uid;
+extern int tty_mode, tty_oldmode;
+# ifndef USE_SETEUID
+static int multipipe[2];
+# endif
+#endif
+
+
+static int ContinuePlease;
+
+static sigret_t
+AttachSigCont SIGDEFARG
+{
+ debug("SigCont()\n");
+ ContinuePlease = 1;
+ SIGRETURN;
+}
+
+static int QueryResult;
+
+static sigret_t
+QueryResultSuccess SIGDEFARG
+{
+ QueryResult = 1;
+ SIGRETURN;
+}
+
+static sigret_t
+QueryResultFail SIGDEFARG
+{
+ QueryResult = 2;
+ SIGRETURN;
+}
+
+/*
+ * Send message to a screen backend.
+ * returns 1 if we could attach one, or 0 if none.
+ * Understands MSG_ATTACH, MSG_DETACH, MSG_POW_DETACH
+ * MSG_CONT, MSG_WINCH and nothing else!
+ *
+ * if type == MSG_ATTACH and sockets are used, attaches
+ * tty file descriptor.
+ */
+
+static int
+WriteMessage(s, m)
+int s;
+struct msg *m;
+{
+ int r, l = sizeof(*m);
+ bool is_socket;
+
+ is_socket = IsSocket(SockPath);
+ if (is_socket && m->type == MSG_ATTACH)
+ return SendAttachMsg(s, m, attach_fd);
+
+ while(l > 0)
+ {
+ r = write(s, (char *)m + (sizeof(*m) - l), l);
+ if (r == -1 && errno == EINTR)
+ continue;
+ if (r == -1 || r == 0)
+ return -1;
+ l -= r;
+ }
+ return 0;
+}
+
+
+int
+Attach(how)
+int how;
+{
+ int n, lasts;
+ struct msg m;
+ struct stat st;
+ char *s;
+ bool is_socket;
+
+ debug2("Attach: how=%d, tty=%s\n", how, attach_tty);
+#ifdef MULTIUSER
+# ifndef USE_SETEUID
+ while ((how == MSG_ATTACH || how == MSG_CONT) && multiattach)
+ {
+ int ret;
+
+ if (pipe(multipipe))
+ Panic(errno, "pipe");
+ if (chmod(attach_tty, 0666))
+ Panic(errno, "chmod %s", attach_tty);
+ tty_oldmode = tty_mode;
+ eff_uid = -1; /* make UserContext fork */
+ real_uid = multi_uid;
+ if ((ret = UserContext()) <= 0)
+ {
+ char dummy;
+ eff_uid = 0;
+ real_uid = own_uid;
+ if (ret < 0)
+ Panic(errno, "UserContext");
+ close(multipipe[1]);
+ read(multipipe[0], &dummy, 1);
+ if (tty_oldmode >= 0)
+ {
+ chmod(attach_tty, tty_oldmode);
+ tty_oldmode = -1;
+ }
+ ret = UserStatus();
+#ifdef LOCK
+ if (ret == SIG_LOCK)
+ LockTerminal();
+ else
+#endif
+#ifdef SIGTSTP
+ if (ret == SIG_STOP)
+ kill(getpid(), SIGTSTP);
+ else
+#endif
+ if (ret == SIG_POWER_BYE)
+ {
+ int ppid;
+ if (setgid(real_gid) || setuid(real_uid))
+ Panic(errno, "setuid/gid");
+ if ((ppid = getppid()) > 1)
+ Kill(ppid, SIGHUP);
+ exit(0);
+ }
+ else
+ exit(ret);
+ dflag = 0;
+#ifdef MULTI
+ xflag = 1;
+#endif
+ how = MSG_ATTACH;
+ continue;
+ }
+ close(multipipe[0]);
+ eff_uid = real_uid;
+ break;
+ }
+# else /* USE_SETEUID */
+ if ((how == MSG_ATTACH || how == MSG_CONT) && multiattach)
+ {
+ real_uid = multi_uid;
+ eff_uid = own_uid;
+#ifdef HAVE_SETRESUID
+ if (setresuid(multi_uid, own_uid, multi_uid))
+ Panic(errno, "setresuid");
+#else
+ xseteuid(multi_uid);
+ xseteuid(own_uid);
+#endif
+ if (chmod(attach_tty, 0666))
+ Panic(errno, "chmod %s", attach_tty);
+ tty_oldmode = tty_mode;
+ }
+# endif /* USE_SETEUID */
+#endif /* MULTIUSER */
+
+ bzero((char *) &m, sizeof(m));
+ m.type = how;
+ m.protocol_revision = MSG_REVISION;
+ strncpy(m.m_tty, attach_tty_is_in_new_ns ? attach_tty_name_in_ns : attach_tty, sizeof(m.m_tty) - 1);
+ m.m_tty[sizeof(m.m_tty) - 1] = 0;
+
+ is_socket = IsSocket(SockPath);
+ if (how == MSG_WINCH)
+ {
+ if ((lasts = MakeClientSocket(0, is_socket)) >= 0)
+ {
+ WriteMessage(lasts, &m);
+ close(lasts);
+ }
+ return 0;
+ }
+
+ if (how == MSG_CONT)
+ {
+ if ((lasts = MakeClientSocket(0, is_socket)) < 0)
+ {
+ Panic(0, "Sorry, cannot contact session \"%s\" again.\r\n",
+ SockName);
+ }
+ }
+ else
+ {
+ n = FindSocket(&lasts, (int *)0, (int *)0, SockMatch, &is_socket);
+ switch (n)
+ {
+ case 0:
+ if (rflag && (rflag & 1) == 0)
+ return 0;
+ if (quietflag)
+ eexit(10);
+ if (SockMatch && *SockMatch) {
+ Panic(0, "There is no screen to be %sed matching %s.",
+ xflag ? "attach" :
+ dflag ? "detach" :
+ "resum", SockMatch);
+ } else {
+ Panic(0, "There is no screen to be %sed.",
+ xflag ? "attach" :
+ dflag ? "detach" :
+ "resum");
+ }
+ /* NOTREACHED */
+ case 1:
+ break;
+ default:
+ if (rflag < 3)
+ {
+ if (quietflag)
+ eexit(10 + n);
+ Panic(0, "Type \"screen [-d] -r [pid.]tty.host\" to resume one of them.");
+ }
+ /* NOTREACHED */
+ }
+ }
+ /*
+ * Go in UserContext. Advantage is, you can kill your attacher
+ * when things go wrong. Any disadvantages? jw.
+ * Do this before the attach to prevent races!
+ */
+#ifdef MULTIUSER
+ if (!multiattach)
+#endif
+ {
+ if (setuid(real_uid))
+ Panic(errno, "setuid");
+ }
+#if defined(MULTIUSER) && defined(USE_SETEUID)
+ else
+ {
+ /* This call to xsetuid should also set the saved uid */
+ xseteuid(real_uid); /* multi_uid, allow backend to send signals */
+ }
+#endif
+ eff_uid = real_uid;
+ if (setgid(real_gid))
+ Panic(errno, "setgid");
+ eff_gid = real_gid;
+
+ debug2("Attach: uid %d euid %d\n", (int)getuid(), (int)geteuid());
+ MasterPid = 0;
+ for (s = SockName; *s; s++)
+ {
+ if (*s > '9' || *s < '0')
+ break;
+ MasterPid = 10 * MasterPid + (*s - '0');
+ }
+ debug1("Attach decided, it is '%s'\n", SockPath);
+ debug1("Attach found MasterPid == %d\n", MasterPid);
+ if (stat(SockPath, &st) == -1)
+ Panic(errno, "stat %s", SockPath);
+ if ((st.st_mode & 0600) != 0600)
+ Panic(0, "Socket is in wrong mode (%03o)", (int)st.st_mode);
+
+ /*
+ * Change: if -x or -r ignore failing -d
+ */
+ if ((xflag || rflag) && dflag && (st.st_mode & 0700) == 0600)
+ dflag = 0;
+
+ /*
+ * Without -x, the mode must match.
+ * With -x the mode is irrelevant unless -d.
+ */
+ if ((dflag || !xflag) && (st.st_mode & 0700) != (dflag ? 0700 : 0600))
+ Panic(0, "That screen is %sdetached.", dflag ? "already " : "not ");
+#ifdef REMOTE_DETACH
+ if (dflag &&
+ (how == MSG_DETACH || how == MSG_POW_DETACH))
+ {
+ m.m.detach.dpid = getpid();
+ strncpy(m.m.detach.duser, LoginName, sizeof(m.m.detach.duser) - 1);
+ m.m.detach.duser[sizeof(m.m.detach.duser) - 1] = 0;
+# ifdef POW_DETACH
+ if (dflag == 2)
+ m.type = MSG_POW_DETACH;
+ else
+# endif
+ m.type = MSG_DETACH;
+ /* If there is no password for the session, or the user enters the correct
+ * password, then we get a SIGCONT. Otherwise we get a SIG_BYE */
+ signal(SIGCONT, AttachSigCont);
+ if (WriteMessage(lasts, &m))
+ Panic(errno, "WriteMessage");
+ close(lasts);
+ while (!ContinuePlease)
+ pause(); /* wait for SIGCONT */
+ signal(SIGCONT, SIG_DFL);
+ ContinuePlease = 0;
+ if (how != MSG_ATTACH)
+ return 0; /* we detached it. jw. */
+ sleep(1); /* we dont want to overrun our poor backend. jw. */
+ if ((lasts = MakeClientSocket(0, is_socket)) == -1)
+ Panic(0, "Cannot contact screen again. Sigh.");
+ m.type = how;
+ }
+#endif
+ ASSERT(how == MSG_ATTACH || how == MSG_CONT);
+ strncpy(m.m.attach.envterm, attach_term, MAXTERMLEN);
+ m.m.attach.envterm[MAXTERMLEN] = 0;
+ debug1("attach: sending %d bytes... ", (int)sizeof(m));
+
+ strncpy(m.m.attach.auser, LoginName, sizeof(m.m.attach.auser) - 1);
+ m.m.attach.auser[sizeof(m.m.attach.auser) - 1] = 0;
+ m.m.attach.esc = DefaultEsc;
+ m.m.attach.meta_esc = DefaultMetaEsc;
+ strncpy(m.m.attach.preselect, preselect ? preselect : "", sizeof(m.m.attach.preselect) - 1);
+ m.m.attach.preselect[sizeof(m.m.attach.preselect) - 1] = 0;
+ m.m.attach.apid = getpid();
+ m.m.attach.adaptflag = adaptflag;
+ m.m.attach.lines = m.m.attach.columns = 0;
+ if ((s = getenv("LINES")))
+ m.m.attach.lines = atoi(s);
+ if ((s = getenv("COLUMNS")))
+ m.m.attach.columns = atoi(s);
+ m.m.attach.encoding = nwin_options.encoding > 0 ? nwin_options.encoding + 1 : 0;
+
+#ifdef REMOTE_DETACH
+#ifdef POW_DETACH
+ if (dflag == 2)
+ m.m.attach.detachfirst = MSG_POW_DETACH;
+ else
+#endif
+ if (dflag)
+ m.m.attach.detachfirst = MSG_DETACH;
+ else
+#endif
+ m.m.attach.detachfirst = MSG_ATTACH;
+
+#ifdef MULTIUSER
+ /* setup CONT signal handler to repair the terminal mode */
+ if (multi && (how == MSG_ATTACH || how == MSG_CONT))
+ signal(SIGCONT, AttachSigCont);
+#endif
+
+ if (WriteMessage(lasts, &m))
+ Panic(errno, "WriteMessage");
+ close(lasts);
+ debug1("Attach(%d): sent\n", m.type);
+#ifdef MULTIUSER
+ if (multi && (how == MSG_ATTACH || how == MSG_CONT))
+ {
+ while (!ContinuePlease)
+ pause(); /* wait for SIGCONT */
+ signal(SIGCONT, SIG_DFL);
+ ContinuePlease = 0;
+# ifndef USE_SETEUID
+ close(multipipe[1]);
+# else
+ xseteuid(own_uid);
+ if (tty_oldmode >= 0)
+ if (chmod(attach_tty, tty_oldmode))
+ Panic(errno, "chmod %s", attach_tty);
+ tty_oldmode = -1;
+ xseteuid(real_uid);
+# endif
+ }
+#endif
+ rflag = 0;
+ return 1;
+}
+
+
+static int AttacherPanic = 0;
+
+#ifdef DEBUG
+static sigret_t
+AttacherChld SIGDEFARG
+{
+ AttacherPanic = 1;
+ SIGRETURN;
+}
+#endif
+
+static sigret_t
+AttacherSigAlarm SIGDEFARG
+{
+#ifdef DEBUG
+ static int tick_cnt = 0;
+ if ((tick_cnt = (tick_cnt + 1) % 4) == 0)
+ debug("tick\n");
+#endif
+ SIGRETURN;
+}
+
+/*
+ * the frontend's Interrupt handler
+ * we forward SIGINT to the poor backend
+ */
+static sigret_t
+AttacherSigInt SIGDEFARG
+{
+ signal(SIGINT, AttacherSigInt);
+ Kill(MasterPid, SIGINT);
+ SIGRETURN;
+}
+
+/*
+ * Unfortunately this is also the SIGHUP handler, so we have to
+ * check if the backend is already detached.
+ */
+
+sigret_t
+AttacherFinit SIGDEFARG
+{
+ struct stat statb;
+ struct msg m;
+ int s;
+ bool is_socket;
+
+ debug("AttacherFinit();\n");
+ signal(SIGHUP, SIG_IGN);
+ /* Check if signal comes from backend */
+ if (stat(SockPath, &statb) == 0 && (statb.st_mode & 0777) != 0600)
+ {
+ debug("Detaching backend!\n");
+ bzero((char *) &m, sizeof(m));
+ strncpy(m.m_tty, attach_tty_is_in_new_ns ? attach_tty_name_in_ns : attach_tty, sizeof(m.m_tty) - 1);
+ m.m_tty[sizeof(m.m_tty) - 1] = 0;
+ debug1("attach_tty is %s\n", attach_tty);
+ m.m.detach.dpid = getpid();
+ m.type = MSG_HANGUP;
+ m.protocol_revision = MSG_REVISION;
+ is_socket = IsSocket(SockPath);
+ if ((s = MakeClientSocket(0, is_socket)) >= 0)
+ {
+ WriteMessage(s, &m);
+ close(s);
+ }
+ }
+#ifdef MULTIUSER
+ if (tty_oldmode >= 0)
+ {
+ if (setuid(own_uid))
+ Panic(errno, "setuid");
+ chmod(attach_tty, tty_oldmode);
+ }
+#endif
+ exit(0);
+ SIGRETURN;
+}
+
+#ifdef POW_DETACH
+static sigret_t
+AttacherFinitBye SIGDEFARG
+{
+ int ppid;
+ debug("AttacherFintBye()\n");
+#if defined(MULTIUSER) && !defined(USE_SETEUID)
+ if (multiattach)
+ exit(SIG_POWER_BYE);
+#endif
+ if (setgid(real_gid))
+ Panic(errno, "setgid");
+#ifdef MULTIUSER
+ if (setuid(own_uid))
+ Panic(errno, "setuid");
+#else
+ if (setuid(real_uid))
+ Panic(errno, "setuid");
+#endif
+ /* we don't want to disturb init (even if we were root), eh? jw */
+ if ((ppid = getppid()) > 1)
+ Kill(ppid, SIGHUP); /* carefully say good bye. jw. */
+ exit(0);
+ SIGRETURN;
+}
+#endif
+
+#if defined(DEBUG) && defined(SIG_NODEBUG)
+static sigret_t
+AttacherNoDebug SIGDEFARG
+{
+ debug("AttacherNoDebug()\n");
+ signal(SIG_NODEBUG, AttacherNoDebug);
+ if (dfp)
+ {
+ debug("debug: closing debug file.\n");
+ fflush(dfp);
+ fclose(dfp);
+ dfp = NULL;
+ }
+ SIGRETURN;
+}
+#endif /* SIG_NODEBUG */
+
+static int SuspendPlease;
+
+static sigret_t
+SigStop SIGDEFARG
+{
+ debug("SigStop()\n");
+ SuspendPlease = 1;
+ SIGRETURN;
+}
+
+#ifdef LOCK
+static int LockPlease;
+
+static sigret_t
+DoLock SIGDEFARG
+{
+# ifdef SYSVSIGS
+ signal(SIG_LOCK, DoLock);
+# endif
+ debug("DoLock()\n");
+ LockPlease = 1;
+ SIGRETURN;
+}
+#endif
+
+#if defined(SIGWINCH) && defined(TIOCGWINSZ)
+static int SigWinchPlease;
+
+static sigret_t
+AttacherWinch SIGDEFARG
+{
+ debug("AttacherWinch()\n");
+ SigWinchPlease = 1;
+ SIGRETURN;
+}
+#endif
+
+
+/*
+ * Attacher loop - no return
+ */
+
+void
+Attacher()
+{
+ signal(SIGHUP, AttacherFinit);
+ signal(SIG_BYE, AttacherFinit);
+#ifdef POW_DETACH
+ signal(SIG_POWER_BYE, AttacherFinitBye);
+#endif
+#if defined(DEBUG) && defined(SIG_NODEBUG)
+ signal(SIG_NODEBUG, AttacherNoDebug);
+#endif
+#ifdef LOCK
+ signal(SIG_LOCK, DoLock);
+#endif
+ signal(SIGINT, AttacherSigInt);
+#ifdef BSDJOBS
+ signal(SIG_STOP, SigStop);
+#endif
+#if defined(SIGWINCH) && defined(TIOCGWINSZ)
+ signal(SIGWINCH, AttacherWinch);
+#endif
+#ifdef DEBUG
+ signal(SIGCHLD, AttacherChld);
+#endif
+ debug("attacher: going for a nap.\n");
+ dflag = 0;
+#ifdef MULTI
+ xflag = 1;
+#endif
+ for (;;)
+ {
+ signal(SIGALRM, AttacherSigAlarm);
+ alarm(15);
+ pause();
+ alarm(0);
+ if (kill(MasterPid, 0) < 0 && errno != EPERM)
+ {
+ debug1("attacher: Panic! MasterPid %d does not exist.\n", MasterPid);
+ AttacherPanic++;
+ }
+ if (AttacherPanic)
+ {
+ fcntl(0, F_SETFL, 0);
+ SetTTY(0, &attach_Mode);
+ printf("\nError: Cannot find master process to attach to!\n");
+ eexit(1);
+ }
+#ifdef BSDJOBS
+ if (SuspendPlease)
+ {
+ SuspendPlease = 0;
+#if defined(MULTIUSER) && !defined(USE_SETEUID)
+ if (multiattach)
+ exit(SIG_STOP);
+#endif
+ signal(SIGTSTP, SIG_DFL);
+ debug("attacher: killing myself SIGTSTP\n");
+ kill(getpid(), SIGTSTP);
+ debug("attacher: continuing from stop\n");
+ signal(SIG_STOP, SigStop);
+ (void) Attach(MSG_CONT);
+ }
+#endif
+#ifdef LOCK
+ if (LockPlease)
+ {
+ LockPlease = 0;
+#if defined(MULTIUSER) && !defined(USE_SETEUID)
+ if (multiattach)
+ exit(SIG_LOCK);
+#endif
+ LockTerminal();
+# ifdef SYSVSIGS
+ signal(SIG_LOCK, DoLock);
+# endif
+ (void) Attach(MSG_CONT);
+ }
+#endif /* LOCK */
+#if defined(SIGWINCH) && defined(TIOCGWINSZ)
+ if (SigWinchPlease)
+ {
+ SigWinchPlease = 0;
+# ifdef SYSVSIGS
+ signal(SIGWINCH, AttacherWinch);
+# endif
+ (void) Attach(MSG_WINCH);
+ }
+#endif /* SIGWINCH */
+ }
+}
+
+#ifdef LOCK
+
+/* ADDED by Rainer Pruy 10/15/87 */
+/* POLISHED by mls. 03/10/91 */
+
+static char LockEnd[] = "Welcome back to screen !!\n";
+
+static sigret_t
+LockHup SIGDEFARG
+{
+ int ppid = getppid();
+ if (setgid(real_gid))
+ Panic(errno, "setgid");
+#ifdef MULTIUSER
+ if (setuid(own_uid))
+ Panic(errno, "setuid");
+#else
+ if (setuid(real_uid))
+ Panic(errno, "setuid");
+#endif
+ if (ppid > 1)
+ Kill(ppid, SIGHUP);
+ exit(0);
+}
+
+static void
+LockTerminal()
+{
+ char *prg;
+ int sig, pid;
+ sigret_t (*sigs[NSIG])__P(SIGPROTOARG);
+
+ for (sig = 1; sig < NSIG; sig++)
+ sigs[sig] = signal(sig, sig == SIGCHLD ? SIG_DFL : SIG_IGN);
+ signal(SIGHUP, LockHup);
+ printf("\n");
+
+ prg = getenv("LOCKPRG");
+ if (prg && strcmp(prg, "builtin") && !access(prg, X_OK))
+ {
+ signal(SIGCHLD, SIG_DFL);
+ debug1("lockterminal: '%s' seems executable, execl it!\n", prg);
+ if ((pid = fork()) == 0)
+ {
+ /* Child */
+ displays = 0; /* beware of Panic() */
+ ServerSocket = -1;
+ if (setgid(real_gid))
+ Panic(errno, "setgid");
+#ifdef MULTIUSER
+ if (setuid(own_uid))
+ Panic(errno, "setuid");
+#else
+ if (setuid(real_uid)) /* this should be done already */
+ Panic(errno, "setuid");
+#endif
+ closeallfiles(0); /* important: /etc/shadow may be open */
+ execl(prg, "SCREEN-LOCK", NULL);
+ exit(errno);
+ }
+ if (pid == -1)
+ Msg(errno, "Cannot lock terminal - fork failed");
+ else
+ {
+#ifdef BSDWAIT
+ union wait wstat;
+#else
+ int wstat;
+#endif
+ int wret;
+
+#ifdef hpux
+ signal(SIGCHLD, SIG_DFL);
+#endif
+ errno = 0;
+ while (((wret = wait(&wstat)) != pid) ||
+ ((wret == -1) && (errno == EINTR))
+ )
+ errno = 0;
+
+ if (errno)
+ {
+ Msg(errno, "Lock");
+ sleep(2);
+ }
+ else if (WTERMSIG(wstat) != 0)
+ {
+ fprintf(stderr, "Lock: %s: Killed by signal: %d%s\n", prg,
+ WTERMSIG(wstat), WIFCORESIG(wstat) ? " (Core dumped)" : "");
+ sleep(2);
+ }
+ else if (WEXITSTATUS(wstat))
+ {
+ debug2("Lock: %s: return code %d\n", prg, WEXITSTATUS(wstat));
+ }
+ else
+ printf("%s", LockEnd);
+ }
+ }
+ else
+ {
+ if (prg)
+ {
+ debug1("lockterminal: '%s' seems NOT executable, we use our builtin\n", prg);
+ }
+ else
+ {
+ debug("lockterminal: using buitin.\n");
+ }
+ screen_builtin_lck();
+ }
+ /* reset signals */
+ for (sig = 1; sig < NSIG; sig++)
+ {
+ if (sigs[sig] != (sigret_t(*)__P(SIGPROTOARG)) -1)
+ signal(sig, sigs[sig]);
+ }
+} /* LockTerminal */
+
+#ifdef USE_PAM
+
+/*
+ * PAM support by Pablo Averbuj <pablo@averbuj.com>
+ */
+
+#include <security/pam_appl.h>
+
+static int PAM_conv __P((int, const struct pam_message **, struct pam_response **, void *));
+
+static int
+PAM_conv(num_msg, msg, resp, appdata_ptr)
+int num_msg;
+const struct pam_message **msg;
+struct pam_response **resp;
+void *appdata_ptr;
+{
+ int replies = 0;
+ struct pam_response *reply = NULL;
+
+ reply = malloc(sizeof(struct pam_response)*num_msg);
+ if (!reply)
+ return PAM_CONV_ERR;
+ #define COPY_STRING(s) (s) ? strdup(s) : NULL
+
+ for (replies = 0; replies < num_msg; replies++)
+ {
+ switch (msg[replies]->msg_style)
+ {
+ case PAM_PROMPT_ECHO_OFF:
+ /* wants password */
+ reply[replies].resp_retcode = PAM_SUCCESS;
+ reply[replies].resp = appdata_ptr ? strdup((char *)appdata_ptr) : 0;
+ break;
+ case PAM_TEXT_INFO:
+ /* ignore the informational mesage */
+ /* but first clear out any drek left by malloc */
+ reply[replies].resp = NULL;
+ break;
+ case PAM_PROMPT_ECHO_ON:
+ /* user name given to PAM already */
+ /* fall through */
+ default:
+ /* unknown or PAM_ERROR_MSG */
+ free(reply);
+ return PAM_CONV_ERR;
+ }
+ }
+ *resp = reply;
+ return PAM_SUCCESS;
+}
+
+static struct pam_conv PAM_conversation = {
+ &PAM_conv,
+ NULL
+};
+
+
+#endif
+
+/* -- original copyright by Luigi Cannelloni 1985 (luigi@faui70.UUCP) -- */
+static void
+screen_builtin_lck()
+{
+ char fullname[100], *cp1, message[100 + 100];
+#ifdef USE_PAM
+ pam_handle_t *pamh = 0;
+ int pam_error;
+ char *tty_name;
+#endif
+ char *pass = 0, mypass[16 + 1], salt[3];
+ int using_pam = 1;
+
+#ifdef USE_PAM
+ if (!ppp->pw_uid)
+ {
+#endif
+ using_pam = 0;
+ pass = ppp->pw_passwd;
+ if (pass == 0 || *pass == 0)
+ {
+ if ((pass = getpass("Key: ")))
+ {
+ strncpy(mypass, pass, sizeof(mypass) - 1);
+ mypass[sizeof(mypass) - 1] = 0;
+ if (*mypass == 0)
+ return;
+ if ((pass = getpass("Again: ")))
+ {
+ if (strcmp(mypass, pass))
+ {
+ fprintf(stderr, "Passwords don't match.\007\n");
+ sleep(2);
+ return;
+ }
+ }
+ }
+ if (pass == 0)
+ {
+ fprintf(stderr, "Getpass error.\007\n");
+ sleep(2);
+ return;
+ }
+
+ salt[0] = 'A' + (int)(time(0) % 26);
+ salt[1] = 'A' + (int)((time(0) >> 6) % 26);
+ salt[2] = 0;
+ pass = crypt(mypass, salt);
+ if (!pass)
+ {
+ fprintf(stderr, "crypt() error.\007\n");
+ sleep(2);
+ return;
+ }
+ pass = ppp->pw_passwd = SaveStr(pass);
+ }
+#ifdef USE_PAM
+ }
+#endif
+
+ debug("screen_builtin_lck looking in gcos field\n");
+ strncpy(fullname, ppp->pw_gecos, sizeof(fullname) - 9);
+ fullname[sizeof(fullname) - 9] = 0;
+
+ if ((cp1 = index(fullname, ',')) != NULL)
+ *cp1 = '\0';
+ if ((cp1 = index(fullname, '&')) != NULL)
+ {
+ strncpy(cp1, ppp->pw_name, 8);
+ cp1[8] = 0;
+ if (*cp1 >= 'a' && *cp1 <= 'z')
+ *cp1 -= 'a' - 'A';
+ }
+
+ sprintf(message, "Screen used by %s%s<%s> on %s.\nPassword:\007",
+ fullname, fullname[0] ? " " : "", ppp->pw_name, HostName);
+
+ /* loop here to wait for correct password */
+ for (;;)
+ {
+ debug("screen_builtin_lck awaiting password\n");
+ errno = 0;
+ if ((cp1 = getpass(message)) == NULL)
+ {
+ AttacherFinit(SIGARG);
+ /* NOTREACHED */
+ }
+ if (using_pam)
+ {
+#ifdef USE_PAM
+ PAM_conversation.appdata_ptr = cp1;
+ pam_error = pam_start("screen", ppp->pw_name, &PAM_conversation, &pamh);
+ if (pam_error != PAM_SUCCESS)
+ AttacherFinit(SIGARG); /* goodbye */
+
+ if (strncmp(attach_tty, "/dev/", 5) == 0)
+ tty_name = attach_tty + 5;
+ else
+ tty_name = attach_tty;
+ pam_error = pam_set_item(pamh, PAM_TTY, tty_name);
+ if (pam_error != PAM_SUCCESS)
+ AttacherFinit(SIGARG); /* goodbye */
+
+ pam_error = pam_authenticate(pamh, 0);
+ pam_end(pamh, pam_error);
+ PAM_conversation.appdata_ptr = 0;
+ if (pam_error == PAM_SUCCESS)
+ break;
+#endif
+ }
+ else
+ {
+ char *buf = crypt(cp1, pass);
+ if (buf && !strncmp(buf, pass, strlen(pass)))
+ break;
+ }
+ debug("screen_builtin_lck: NO!!!!!\n");
+ bzero(cp1, strlen(cp1));
+ }
+ bzero(cp1, strlen(cp1));
+ debug("password ok.\n");
+}
+
+#endif /* LOCK */
+
+
+void
+SendCmdMessage(sty, match, av, query)
+char *sty;
+char *match;
+char **av;
+int query;
+{
+ int i, s;
+ struct msg m;
+ char *p;
+ int len, n;
+ bool is_socket;
+
+ if (sty == 0)
+ {
+ i = FindSocket(&s, (int *)0, (int *)0, match, &is_socket);
+ if (i == 0)
+ Panic(0, "No screen session found.");
+ if (i != 1)
+ Panic(0, "Use -S to specify a session.");
+ }
+ else
+ {
+#ifdef NAME_MAX
+ if (strlen(sty) > NAME_MAX)
+ sty[NAME_MAX] = 0;
+#endif
+ if (strlen(sty) > 2 * MAXSTR - 1)
+ sty[2 * MAXSTR - 1] = 0;
+ sprintf(SockPath + strlen(SockPath), "/%s", sty);
+ is_socket = IsSocket(SockPath);
+ if ((s = MakeClientSocket(1, is_socket)) == -1)
+ exit(1);
+ }
+ bzero((char *)&m, sizeof(m));
+ m.type = query ? MSG_QUERY : MSG_COMMAND;
+ if (attach_tty)
+ {
+ strncpy(m.m_tty, attach_tty_is_in_new_ns ? attach_tty_name_in_ns : attach_tty, sizeof(m.m_tty) - 1);
+ m.m_tty[sizeof(m.m_tty) - 1] = 0;
+ }
+ p = m.m.command.cmd;
+ n = 0;
+ for (; *av && n < MAXARGS - 1; ++av, ++n)
+ {
+ len = strlen(*av) + 1;
+ if (p + len >= m.m.command.cmd + sizeof(m.m.command.cmd) - 1)
+ break;
+ strcpy(p, *av);
+ p += len;
+ }
+ *p = 0;
+ m.m.command.nargs = n;
+ strncpy(m.m.attach.auser, LoginName, sizeof(m.m.attach.auser) - 1);
+ m.m.command.auser[sizeof(m.m.command.auser) - 1] = 0;
+ m.protocol_revision = MSG_REVISION;
+ strncpy(m.m.command.preselect, preselect ? preselect : "", sizeof(m.m.command.preselect) - 1);
+ m.m.command.preselect[sizeof(m.m.command.preselect) - 1] = 0;
+ m.m.command.apid = getpid();
+ debug1("SendCommandMsg writing '%s'\n", m.m.command.cmd);
+ if (query)
+ {
+ /* Create a server socket so we can get back the result */
+ char *sp = SockPath + strlen(SockPath);
+ char query[] = "-queryX";
+ char c;
+ int r = -1;
+ for (c = 'A'; c <= 'Z'; c++)
+ {
+ query[6] = c;
+ strcpy(sp, query); /* XXX: strncpy? */
+ if ((r = MakeServerSocket(is_socket)) >= 0)
+ break;
+ }
+ if (r < 0)
+ {
+ for (c = '0'; c <= '9'; c++)
+ {
+ query[6] = c;
+ strcpy(sp, query);
+ if ((r = MakeServerSocket(is_socket)) >= 0)
+ break;
+ }
+ }
+
+ if (r < 0)
+ Panic(0, "Could not create a listening socket to read the results.");
+
+ strncpy(m.m.command.writeback, SockPath, sizeof(m.m.command.writeback) - 1);
+ m.m.command.writeback[sizeof(m.m.command.writeback) - 1] = '\0';
+
+ /* Send the message, then wait for a response */
+ signal(SIGCONT, QueryResultSuccess);
+ signal(SIG_BYE, QueryResultFail);
+ if (WriteMessage(s, &m))
+ Msg(errno, "write");
+ close(s);
+ while (!QueryResult)
+ pause();
+ signal(SIGCONT, SIG_DFL);
+ signal(SIG_BYE, SIG_DFL);
+
+ /* Read the result and spit it out to stdout */
+ ReceiveRaw(r);
+ unlink(SockPath);
+ if (QueryResult == 2) /* An error happened */
+ exit(1);
+ }
+ else
+ {
+ if (WriteMessage(s, &m))
+ Msg(errno, "write");
+ close(s);
+ }
+}
+
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-24 01:02:55 +0000