Fix a pty-freeing error which caused a segfault if you attempted to
[u/mdw/putty] / unix / uxpty.c
index afd64af..5ebd050 100644 (file)
@@ -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
@@ -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
     }
 }
@@ -606,6 +634,7 @@ int pty_real_select_result(Pty pty, int event, int status)
        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));
@@ -697,6 +726,7 @@ static const char *pty_init(void *frontend, void **backend_handle, Conf *conf,
 
     if (single_pty) {
        pty = single_pty;
+        assert(pty->conf == NULL);
     } else {
        pty = snew(struct pty_tag);
        pty->master_fd = pty->slave_fd = -1;
@@ -732,21 +762,23 @@ static const char *pty_init(void *frontend, void **backend_handle, Conf *conf,
      * Stamp utmp (that is, tell the utmp helper process to do so),
      * or not.
      */
-    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 if (pty_utmp_helper_pipe >= 0) {
-       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
@@ -835,9 +867,41 @@ static const char *pty_init(void *frontend, void **backend_handle, Conf *conf,
        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 (conf_get_int(conf, CONF_login_shell)) {
@@ -905,7 +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)