Fix a pty-freeing error which caused a segfault if you attempted to
[u/mdw/putty] / unix / uxpty.c
index bdfa5ab..5ebd050 100644 (file)
@@ -76,7 +76,7 @@ typedef struct pty_tag *Pty;
 static int pty_signal_pipe[2] = { -1, -1 };   /* obviously bogus initial val */
 
 struct pty_tag {
-    Config cfg;
+    Conf *conf;
     int master_fd, slave_fd;
     void *frontend;
     char name[FILENAME_MAX];
@@ -167,8 +167,8 @@ static tree234 *ptys_by_pid = NULL;
 static Pty single_pty = NULL;
 
 #ifndef OMIT_UTMP
-static pid_t pty_utmp_helper_pid;
-static int pty_utmp_helper_pipe;
+static pid_t pty_utmp_helper_pid = -1;
+static int pty_utmp_helper_pipe = -1;
 static int pty_stamped_utmp;
 static struct utmpx utmp_entry;
 #endif
@@ -270,7 +270,6 @@ static void fatal_sig_handler(int signum)
 {
     putty_signal(signum, SIG_DFL);
     cleanup_utmp();
-    setuid(getuid());
     raise(signum);
 }
 #endif
@@ -335,12 +334,28 @@ static void pty_open_master(Pty pty)
     chown(pty->name, getuid(), gp ? gp->gr_gid : -1);
     chmod(pty->name, 0600);
 #else
-    pty->master_fd = open("/dev/ptmx", O_RDWR);
+
+    const int flags = O_RDWR
+#ifdef O_NOCTTY
+        | O_NOCTTY
+#endif
+        ;
+
+#ifdef HAVE_POSIX_OPENPT
+    pty->master_fd = posix_openpt(flags);
+
+    if (pty->master_fd < 0) {
+       perror("posix_openpt");
+       exit(1);
+    }
+#else
+    pty->master_fd = open("/dev/ptmx", flags);
 
     if (pty->master_fd < 0) {
        perror("/dev/ptmx: open");
        exit(1);
     }
+#endif
 
     if (grantpt(pty->master_fd) < 0) {
        perror("grantpt");
@@ -396,6 +411,7 @@ void pty_pre_init(void)
 #endif
 
     pty = single_pty = snew(struct pty_tag);
+    pty->conf = NULL;
     bufchain_init(&pty->output_data);
 
     /* set the child signal handler straight away; it needs to be set
@@ -408,106 +424,106 @@ void pty_pre_init(void)
 
     if (geteuid() != getuid() || getegid() != getgid()) {
        pty_open_master(pty);
-    }
 
 #ifndef OMIT_UTMP
-    /*
-     * Fork off the utmp helper.
-     */
-    if (pipe(pipefd) < 0) {
-       perror("pterm: pipe");
-       exit(1);
-    }
-    cloexec(pipefd[0]);
-    cloexec(pipefd[1]);
-    pid = fork();
-    if (pid < 0) {
-       perror("pterm: fork");
-       exit(1);
-    } else if (pid == 0) {
-       char display[128], buffer[128];
-       int dlen, ret;
-
-       close(pipefd[1]);
-       /*
-        * Now sit here until we receive a display name from the
-        * other end of the pipe, and then stamp utmp. Unstamp utmp
-        * again, and exit, when the pipe closes.
-        */
+        /*
+         * Fork off the utmp helper.
+         */
+        if (pipe(pipefd) < 0) {
+            perror("pterm: pipe");
+            exit(1);
+        }
+        cloexec(pipefd[0]);
+        cloexec(pipefd[1]);
+        pid = fork();
+        if (pid < 0) {
+            perror("pterm: fork");
+            exit(1);
+        } else if (pid == 0) {
+            char display[128], buffer[128];
+            int dlen, ret;
+
+            close(pipefd[1]);
+            /*
+             * Now sit here until we receive a display name from the
+             * other end of the pipe, and then stamp utmp. Unstamp utmp
+             * again, and exit, when the pipe closes.
+             */
 
-       dlen = 0;
-       while (1) {
+            dlen = 0;
+            while (1) {
            
-           ret = read(pipefd[0], buffer, lenof(buffer));
-           if (ret <= 0) {
-               cleanup_utmp();
-               _exit(0);
-           } else if (!pty_stamped_utmp) {
-               if (dlen < lenof(display))
-                   memcpy(display+dlen, buffer,
-                          min(ret, lenof(display)-dlen));
-               if (buffer[ret-1] == '\0') {
-                   /*
-                    * Now we have a display name. NUL-terminate
-                    * it, and stamp utmp.
-                    */
-                   display[lenof(display)-1] = '\0';
-                   /*
-                    * Trap as many fatal signals as we can in the
-                    * hope of having the best possible chance to
-                    * clean up utmp before termination. We are
-                    * unfortunately unprotected against SIGKILL,
-                    * but that's life.
-                    */
-                   putty_signal(SIGHUP, fatal_sig_handler);
-                   putty_signal(SIGINT, fatal_sig_handler);
-                   putty_signal(SIGQUIT, fatal_sig_handler);
-                   putty_signal(SIGILL, fatal_sig_handler);
-                   putty_signal(SIGABRT, fatal_sig_handler);
-                   putty_signal(SIGFPE, fatal_sig_handler);
-                   putty_signal(SIGPIPE, fatal_sig_handler);
-                   putty_signal(SIGALRM, fatal_sig_handler);
-                   putty_signal(SIGTERM, fatal_sig_handler);
-                   putty_signal(SIGSEGV, fatal_sig_handler);
-                   putty_signal(SIGUSR1, fatal_sig_handler);
-                   putty_signal(SIGUSR2, fatal_sig_handler);
+                ret = read(pipefd[0], buffer, lenof(buffer));
+                if (ret <= 0) {
+                    cleanup_utmp();
+                    _exit(0);
+                } else if (!pty_stamped_utmp) {
+                    if (dlen < lenof(display))
+                        memcpy(display+dlen, buffer,
+                               min(ret, lenof(display)-dlen));
+                    if (buffer[ret-1] == '\0') {
+                        /*
+                         * Now we have a display name. NUL-terminate
+                         * it, and stamp utmp.
+                         */
+                        display[lenof(display)-1] = '\0';
+                        /*
+                         * Trap as many fatal signals as we can in the
+                         * hope of having the best possible chance to
+                         * clean up utmp before termination. We are
+                         * unfortunately unprotected against SIGKILL,
+                         * but that's life.
+                         */
+                        putty_signal(SIGHUP, fatal_sig_handler);
+                        putty_signal(SIGINT, fatal_sig_handler);
+                        putty_signal(SIGQUIT, fatal_sig_handler);
+                        putty_signal(SIGILL, fatal_sig_handler);
+                        putty_signal(SIGABRT, fatal_sig_handler);
+                        putty_signal(SIGFPE, fatal_sig_handler);
+                        putty_signal(SIGPIPE, fatal_sig_handler);
+                        putty_signal(SIGALRM, fatal_sig_handler);
+                        putty_signal(SIGTERM, fatal_sig_handler);
+                        putty_signal(SIGSEGV, fatal_sig_handler);
+                        putty_signal(SIGUSR1, fatal_sig_handler);
+                        putty_signal(SIGUSR2, fatal_sig_handler);
 #ifdef SIGBUS
-                   putty_signal(SIGBUS, fatal_sig_handler);
+                        putty_signal(SIGBUS, fatal_sig_handler);
 #endif
 #ifdef SIGPOLL
-                   putty_signal(SIGPOLL, fatal_sig_handler);
+                        putty_signal(SIGPOLL, fatal_sig_handler);
 #endif
 #ifdef SIGPROF
-                   putty_signal(SIGPROF, fatal_sig_handler);
+                        putty_signal(SIGPROF, fatal_sig_handler);
 #endif
 #ifdef SIGSYS
-                   putty_signal(SIGSYS, fatal_sig_handler);
+                        putty_signal(SIGSYS, fatal_sig_handler);
 #endif
 #ifdef SIGTRAP
-                   putty_signal(SIGTRAP, fatal_sig_handler);
+                        putty_signal(SIGTRAP, fatal_sig_handler);
 #endif
 #ifdef SIGVTALRM
-                   putty_signal(SIGVTALRM, fatal_sig_handler);
+                        putty_signal(SIGVTALRM, fatal_sig_handler);
 #endif
 #ifdef SIGXCPU
-                   putty_signal(SIGXCPU, fatal_sig_handler);
+                        putty_signal(SIGXCPU, fatal_sig_handler);
 #endif
 #ifdef SIGXFSZ
-                   putty_signal(SIGXFSZ, fatal_sig_handler);
+                        putty_signal(SIGXFSZ, fatal_sig_handler);
 #endif
 #ifdef SIGIO
-                   putty_signal(SIGIO, fatal_sig_handler);
+                        putty_signal(SIGIO, fatal_sig_handler);
 #endif
-                   setup_utmp(pty->name, display);
-               }
-           }
-       }
-    } else {
-       close(pipefd[0]);
-       pty_utmp_helper_pid = pid;
-       pty_utmp_helper_pipe = pipefd[1];
-    }
+                        setup_utmp(pty->name, display);
+                    }
+                }
+            }
+        } else {
+            close(pipefd[0]);
+            pty_utmp_helper_pid = pid;
+            pty_utmp_helper_pipe = pipefd[1];
+        }
 #endif
+    }
 
     /* Drop privs. */
     {
@@ -515,11 +531,23 @@ void pty_pre_init(void)
        int gid = getgid(), uid = getuid();
        int setresgid(gid_t, gid_t, gid_t);
        int setresuid(uid_t, uid_t, uid_t);
-       setresgid(gid, gid, gid);
-       setresuid(uid, uid, uid);
+       if (setresgid(gid, gid, gid) < 0) {
+            perror("setresgid");
+            exit(1);
+        }
+       if (setresuid(uid, uid, uid) < 0) {
+            perror("setresuid");
+            exit(1);
+        }
 #else
-       setgid(getgid());
-       setuid(getuid());
+       if (setgid(getgid()) < 0) {
+            perror("setgid");
+            exit(1);
+        }
+       if (setuid(getuid()) < 0) {
+            perror("setuid");
+            exit(1);
+        }
 #endif
     }
 }
@@ -588,6 +616,8 @@ int pty_real_select_result(Pty pty, int event, int status)
     }
 
     if (finished && !pty->finished) {
+       int close_on_exit;
+
        uxsel_del(pty->master_fd);
        pty_close(pty);
        pty->master_fd = -1;
@@ -600,9 +630,11 @@ int pty_real_select_result(Pty pty, int event, int status)
         * Only On Clean and it wasn't a clean exit) do we output a
         * `terminated' message.
         */
-       if (pty->cfg.close_on_exit == FORCE_OFF ||
-           (pty->cfg.close_on_exit == AUTO && pty->exit_code != 0)) {
+       close_on_exit = conf_get_int(pty->conf, CONF_close_on_exit);
+       if (close_on_exit == FORCE_OFF ||
+           (close_on_exit == AUTO && pty->exit_code != 0)) {
            char message[512];
+            message[0] = '\0';
            if (WIFEXITED(pty->exit_code))
                sprintf(message, "\r\n[pterm: process terminated with exit"
                        " code %d]\r\n", WEXITSTATUS(pty->exit_code));
@@ -681,7 +713,7 @@ static void pty_uxsel_setup(Pty pty)
  * Also places the canonical host name into `realhost'. It must be
  * freed by the caller.
  */
-static const char *pty_init(void *frontend, void **backend_handle, Config *cfg,
+static const char *pty_init(void *frontend, void **backend_handle, Conf *conf,
                            char *host, int port, char **realhost, int nodelay,
                            int keepalive)
 {
@@ -694,6 +726,7 @@ static const char *pty_init(void *frontend, void **backend_handle, Config *cfg,
 
     if (single_pty) {
        pty = single_pty;
+        assert(pty->conf == NULL);
     } else {
        pty = snew(struct pty_tag);
        pty->master_fd = pty->slave_fd = -1;
@@ -705,9 +738,9 @@ static const char *pty_init(void *frontend, void **backend_handle, Config *cfg,
     pty->frontend = frontend;
     *backend_handle = NULL;           /* we can't sensibly use this, sadly */
 
-    pty->cfg = *cfg;                  /* structure copy */
-    pty->term_width = cfg->width;
-    pty->term_height = cfg->height;
+    pty->conf = conf_copy(conf);
+    pty->term_width = conf_get_int(conf, CONF_width);
+    pty->term_height = conf_get_int(conf, CONF_height);
 
     if (pty->master_fd < 0)
        pty_open_master(pty);
@@ -719,7 +752,8 @@ static const char *pty_init(void *frontend, void **backend_handle, Config *cfg,
     {
        struct termios attrs;
        tcgetattr(pty->master_fd, &attrs);
-       attrs.c_cc[VERASE] = cfg->bksp_is_delete ? '\177' : '\010';
+       attrs.c_cc[VERASE] = conf_get_int(conf, CONF_bksp_is_delete)
+           ? '\177' : '\010';
        tcsetattr(pty->master_fd, TCSANOW, &attrs);
     }
 
@@ -728,21 +762,23 @@ static const char *pty_init(void *frontend, void **backend_handle, Config *cfg,
      * Stamp utmp (that is, tell the utmp helper process to do so),
      * or not.
      */
-    if (!cfg->stamp_utmp) {
-       close(pty_utmp_helper_pipe);   /* just let the child process die */
-       pty_utmp_helper_pipe = -1;
-    } else {
-       char *location = get_x_display(pty->frontend);
-       int len = strlen(location)+1, pos = 0;   /* +1 to include NUL */
-       while (pos < len) {
-           int ret = write(pty_utmp_helper_pipe, location+pos, len - pos);
-           if (ret < 0) {
-               perror("pterm: writing to utmp helper process");
-               close(pty_utmp_helper_pipe);   /* arrgh, just give up */
-               pty_utmp_helper_pipe = -1;
-               break;
-           }
-           pos += ret;
+    if (pty_utmp_helper_pipe >= 0) {   /* if it's < 0, we can't anyway */
+        if (!conf_get_int(conf, CONF_stamp_utmp)) {
+            close(pty_utmp_helper_pipe);   /* just let the child process die */
+            pty_utmp_helper_pipe = -1;
+        } else {
+            char *location = get_x_display(pty->frontend);
+            int len = strlen(location)+1, pos = 0;   /* +1 to include NUL */
+            while (pos < len) {
+                int ret = write(pty_utmp_helper_pipe, location+pos, len - pos);
+                if (ret < 0) {
+                    perror("pterm: writing to utmp helper process");
+                    close(pty_utmp_helper_pipe);   /* arrgh, just give up */
+                    pty_utmp_helper_pipe = -1;
+                    break;
+                }
+                pos += ret;
+            }
        }
     }
 #endif
@@ -787,7 +823,8 @@ static const char *pty_init(void *frontend, void **backend_handle, Config *cfg,
        close(open(pty->name, O_WRONLY, 0));
        setpgid(pgrp, pgrp);
        {
-           char *term_env_var = dupprintf("TERM=%s", cfg->termtype);
+           char *term_env_var = dupprintf("TERM=%s",
+                                          conf_get_str(conf, CONF_termtype));
            putenv(term_env_var);
            /* We mustn't free term_env_var, as putenv links it into the
             * environment in place.
@@ -803,18 +840,12 @@ static const char *pty_init(void *frontend, void **backend_handle, Config *cfg,
        }
 #endif
        {
-           char *e = cfg->environmt;
-           char *var, *varend, *val, *varval;
-           while (*e) {
-               var = e;
-               while (*e && *e != '\t') e++;
-               varend = e;
-               if (*e == '\t') e++;
-               val = e;
-               while (*e) e++;
-               e++;
-
-               varval = dupprintf("%.*s=%s", varend-var, var, val);
+           char *key, *val;
+
+           for (val = conf_get_str_strs(conf, CONF_environmt, NULL, &key);
+                val != NULL;
+                val = conf_get_str_strs(conf, CONF_environmt, key, &key)) {
+               char *varval = dupcat(key, "=", val, NULL);
                putenv(varval);
                /*
                 * We must not free varval, since putenv links it
@@ -836,12 +867,44 @@ static const char *pty_init(void *frontend, void **backend_handle, Config *cfg,
        putty_signal(SIGQUIT, SIG_DFL);
        putty_signal(SIGPIPE, SIG_DFL);
        block_signal(SIGCHLD, 0);
-       if (pty_argv)
+       if (pty_argv) {
+            /*
+             * Exec the exact argument list we were given.
+             */
            execvp(pty_argv[0], pty_argv);
-       else {
+            /*
+             * If that fails, and if we had exactly one argument, pass
+             * that argument to $SHELL -c.
+             *
+             * This arranges that we can _either_ follow 'pterm -e'
+             * with a list of argv elements to be fed directly to
+             * exec, _or_ with a single argument containing a command
+             * to be parsed by a shell (but, in cases of doubt, the
+             * former is more reliable).
+             *
+             * A quick survey of other terminal emulators' -e options
+             * (as of Debian squeeze) suggests that:
+             *
+             *  - xterm supports both modes, more or less like this
+             *  - gnome-terminal will only accept a one-string shell command
+             *  - Eterm, kterm and rxvt will only accept a list of
+             *    argv elements (as did older versions of pterm).
+             *
+             * It therefore seems important to support both usage
+             * modes in order to be a drop-in replacement for either
+             * xterm or gnome-terminal, and hence for anyone's
+             * plausible uses of the Debian-style alias
+             * 'x-terminal-emulator'...
+             */
+            if (pty_argv[1] == NULL) {
+                char *shell = getenv("SHELL");
+                if (shell)
+                    execl(shell, shell, "-c", pty_argv[0], (void *)NULL);
+            }
+        } else {
            char *shell = getenv("SHELL");
            char *shellname;
-           if (cfg->login_shell) {
+           if (conf_get_int(conf, CONF_login_shell)) {
                char *p = strrchr(shell, '/');
                shellname = snewn(2+strlen(shell), char);
                p = p ? p+1 : shell;
@@ -884,7 +947,7 @@ static const char *pty_init(void *frontend, void **backend_handle, Config *cfg,
     return NULL;
 }
 
-static void pty_reconfig(void *handle, Config *cfg)
+static void pty_reconfig(void *handle, Conf *conf)
 {
     Pty pty = (Pty)handle;
     /*
@@ -892,7 +955,7 @@ static void pty_reconfig(void *handle, Config *cfg)
      * unfortunately we do need to pick up the setting of Close On
      * Exit so we know whether to give a `terminated' message.
      */
-    pty->cfg = *cfg;                  /* structure copy */
+    conf_copy_into(pty->conf, conf);
 }
 
 /*
@@ -906,7 +969,17 @@ static void pty_free(void *handle)
     del234(ptys_by_pid, pty);
     del234(ptys_by_fd, pty);
 
-    sfree(pty);
+    conf_free(pty->conf);
+    pty->conf = NULL;
+
+    if (pty == single_pty) {
+        /*
+         * Leave this structure around in case we need to Restart
+         * Session.
+         */
+    } else {
+        sfree(pty);
+    }
 }
 
 static void pty_try_write(Pty pty)