Changeset 2725 in MondoRescue for branches/2.2.9/mindi-busybox/console-tools/openvt.c

Timestamp:

Feb 25, 2011, 9:26:54 PM (13 years ago)

Author:

Bruno Cornec

Message:

• Update mindi-busybox to 1.18.3 to avoid problems with the tar command which is now failing on recent versions with busybox 1.7.3

File:

• branches/2.2.9/mindi-busybox/console-tools/openvt.c (modified) (1 diff)

branches/2.2.9/mindi-busybox/console-tools/openvt.c

@@ -6 +6 @@
  *  hacked by Tito <farmatito@tiscali.it>
  *
- * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
 
-/* getopt not needed */
-
+#include <linux/vt.h>
 #include "libbb.h"
 
-int openvt_main(int argc, char **argv);
-int openvt_main(int argc, char **argv)
+/* "Standard" openvt's man page (we do not support all of this):
+
+openvt [-c NUM] [-fsulv] [--] [command [args]]
+
+Find the first available VT, and run command on it. Stdio is directed
+to that VT. If no command is specified then $SHELL is used.
+
+-c NUM
+    Use the given VT number, not the first free one.
+-f
+    Force opening a VT: don't try to check if VT is already in use.
+-s
+    Switch to the new VT when starting the command.
+    The VT of the new command will be made the new current VT.
+-u
+    Figure out the owner of the current VT, and run login as that user.
+    Suitable to be called by init. Shouldn't be used with -c or -l.
+-l
+    Make the command a login shell: a "-" is prepended to the argv[0]
+    when command is executed.
+-v
+    Verbose.
+-w
+    Wait for command to complete. If -w and -s are used together,
+    switch back to the controlling terminal when the command completes.
+
+bbox:
+-u: not implemented
+-f: always in effect
+-l: not implemented, ignored
+-v: ignored
+-ws: does NOT switch back
+*/
+
+/* Helper: does this fd understand VT_xxx? */
+static int not_vt_fd(int fd)
 {
-    char vtname[sizeof(VC_FORMAT) + 2];
+    struct vt_stat vtstat;
+    return ioctl(fd, VT_GETSTATE, &vtstat); /* !0: error, it's not VT fd */
+}
 
-    if (argc < 3)
-        bb_show_usage();
+/* Helper: get a fd suitable for VT_xxx */
+static int get_vt_fd(void)
+{
+    int fd;
 
-    /* check for illegal vt number: < 1 or > 63 */
-    sprintf(vtname, VC_FORMAT, (int)xatou_range(argv[1], 1, 63));
+    /* Do we, by chance, already have it? */
+    for (fd = 0; fd < 3; fd++)
+        if (!not_vt_fd(fd))
+            return fd;
+    fd = open(DEV_CONSOLE, O_RDONLY | O_NONBLOCK);
+    if (fd >= 0 && !not_vt_fd(fd))
+        return fd;
+    bb_error_msg_and_die("can't find open VT");
+}
 
-    bb_daemonize_or_rexec(DAEMON_CLOSE_EXTRA_FDS, argv);
-    /* grab new one */
-    close(0);
+static int find_free_vtno(void)
+{
+    int vtno;
+    int fd = get_vt_fd();
+
+    errno = 0;
+    /*xfunc_error_retval = 3; - do we need compat? */
+    if (ioctl(fd, VT_OPENQRY, &vtno) != 0 || vtno <= 0)
+        bb_perror_msg_and_die("can't find open VT");
+// Not really needed, grep for DAEMON_ONLY_SANITIZE
+//  if (fd > 2)
+//      close(fd);
+    return vtno;
+}
+
+/* vfork scares gcc, it generates bigger code.
+ * Keep it away from main program.
+ * TODO: move to libbb; or adapt existing libbb's spawn().
+ */
+static NOINLINE void vfork_child(char **argv)
+{
+    if (vfork() == 0) {
+        /* CHILD */
+        /* Try to make this VT our controlling tty */
+        setsid(); /* lose old ctty */
+        ioctl(STDIN_FILENO, TIOCSCTTY, 0 /* 0: don't forcibly steal */);
+        //bb_error_msg("our sid %d", getsid(0));
+        //bb_error_msg("our pgrp %d", getpgrp());
+        //bb_error_msg("VT's sid %d", tcgetsid(0));
+        //bb_error_msg("VT's pgrp %d", tcgetpgrp(0));
+        BB_EXECVP_or_die(argv);
+    }
+}
+
+int openvt_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int openvt_main(int argc UNUSED_PARAM, char **argv)
+{
+    char vtname[sizeof(VC_FORMAT) + sizeof(int)*3];
+    struct vt_stat vtstat;
+    char *str_c;
+    int vtno;
+    int flags;
+    enum {
+        OPT_c = (1 << 0),
+        OPT_w = (1 << 1),
+        OPT_s = (1 << 2),
+        OPT_l = (1 << 3),
+        OPT_f = (1 << 4),
+        OPT_v = (1 << 5),
+    };
+
+    /* "+" - stop on first non-option */
+    flags = getopt32(argv, "+c:wslfv", &str_c);
+    argv += optind;
+
+    if (flags & OPT_c) {
+        /* Check for illegal vt number: < 1 or > 63 */
+        vtno = xatou_range(str_c, 1, 63);
+    } else {
+        vtno = find_free_vtno();
+    }
+
+    /* Grab new VT */
+    sprintf(vtname, VC_FORMAT, vtno);
+    /* (Try to) clean up stray open fds above fd 2 */
+    bb_daemonize_or_rexec(DAEMON_CLOSE_EXTRA_FDS | DAEMON_ONLY_SANITIZE, NULL);
+    close(STDIN_FILENO);
+    /*setsid(); - BAD IDEA: after we exit, child is SIGHUPed... */
     xopen(vtname, O_RDWR);
-    dup2(0, STDOUT_FILENO);
-    dup2(0, STDERR_FILENO);
+    xioctl(STDIN_FILENO, VT_GETSTATE, &vtstat);
 
-    BB_EXECVP(argv[2], &argv[2]);
-    _exit(1);
+    if (flags & OPT_s) {
+        console_make_active(STDIN_FILENO, vtno);
+    }
+
+    if (!argv[0]) {
+        argv--;
+        argv[0] = getenv("SHELL");
+        if (!argv[0])
+            argv[0] = (char *) DEFAULT_SHELL;
+        /*argv[1] = NULL; - already is */
+    }
+
+    xdup2(STDIN_FILENO, STDOUT_FILENO);
+    xdup2(STDIN_FILENO, STDERR_FILENO);
+
+#ifdef BLOAT
+    {
+    /* Handle -l (login shell) option */
+    const char *prog = argv[0];
+    if (flags & OPT_l)
+        argv[0] = xasprintf("-%s", argv[0]);
+    }
+#endif
+
+    vfork_child(argv);
+    if (flags & OPT_w) {
+        /* We have only one child, wait for it */
+        safe_waitpid(-1, NULL, 0); /* loops on EINTR */
+        if (flags & OPT_s) {
+            console_make_active(STDIN_FILENO, vtstat.v_active);
+            // Compat: even with -c N (try to) disallocate:
+            // # /usr/app/kbd-1.12/bin/openvt -f -c 9 -ws sleep 5
+            // openvt: could not deallocate console 9
+            xioctl(STDIN_FILENO, VT_DISALLOCATE, (void*)(ptrdiff_t)vtno);
+        }
+    }
+    return EXIT_SUCCESS;
 }