Implement emergency shell.

* src/pies.c (main): Move init-specific command line
handling to sysvinit_parse_argv.
* src/pies.h (dfl_level): Remove extern.
(sysvinit_parse_argv): New proto.
* src/sysvinit.c (sysvinit_parse_argv): New function.
(sysvinit_begin): Start emergency shell, if requested.

4 files changed, 95 insertions, 25 deletions

diff --git a/src/pies.c b/src/pies.c
index 3734b47..653a865 100644
--- a/src/pies.c
+++ b/src/pies.c
@@ -1924,13 +1924,12 @@ set_state_file_names (const char *base)
 size_t pies_master_argc;
 char **pies_master_argv;
 
 int
 main (int argc, char **argv)
 {
-  int index;
   pid_t pid;
   extern char **environ;
   struct grecs_list_entry *ep;
   int diag_flags;
   
   set_program_name (argv[0]);
@@ -1998,24 +1997,30 @@ main (int argc, char **argv)
 	  config_file_add_type (CONF_PIES, "/etc/pies.init");
 	}
 #else
       config_file_add_type (CONF_INITTAB, "/etc/inittab");
       config_file_add_type (CONF_PIES, "/etc/pies.init");
 #endif
-      for (index = 1; index < argc; index++)
+      sysvinit_parse_argv (argc, argv);
+    }
+  else
+    {
+      int index;
+
+      parse_options (argc, argv, &index);
+      argc -= index;
+      argv += index;
+      
+      if (argc && !(command == COM_RESTART_COMPONENT
+		    || command == COM_TRACE_DEPEND
+		    || command == COM_TRACE_PREREQ))
 	{
-	  if (!strcmp (argv[index], "single") || !strcmp (argv[index], "-s"))
-	    dfl_level = 'S';
-	  else if (strchr("0123456789sS", argv[index][0]) && !argv[index][1])
-	    {
-	      dfl_level = toupper (argv[index][0]);
-	    }	  
+	  logmsg (LOG_ERR, "extra command line arguments");
+	  exit (EX_USAGE);
 	}
     }
-  else
-    parse_options (argc, argv, &index);
   
   if (!instance)
     {
       instance = strrchr (program_name, '/');
       if (!instance)
 	instance = (char*) program_name;
@@ -2056,21 +2061,12 @@ main (int argc, char **argv)
   if (lint_mode)
     exit (0);
 
   /* Re-setup logging: it might have been reset in the config file */
   diag_setup (log_to_stderr_only ? DIAG_TO_STDERR : 0);
   
-  if (argc != index
-      && !(command == COM_RESTART_COMPONENT
-	   || command == COM_TRACE_DEPEND
-	   || command == COM_TRACE_PREREQ))
-    {
-      logmsg (LOG_ERR, "extra command line arguments");
-      exit (EX_CONFIG);
-    }
-
   if (!control.url)
     {
       char const *str = default_control_url[init_process];
       if (pies_url_create (&control.url, str))
 	{
 	  logmsg (LOG_CRIT, _("%s: cannot create control URL: %s"),
@@ -2083,13 +2079,13 @@ main (int argc, char **argv)
   switch (command)
     {
     case COM_RESTART_COMPONENT:
       pies_priv_setup (&pies_privs);
       if (pies_umask)
 	umask (pies_umask);
-      exit (request_restart_components (argc - index, argv + index));
+      exit (request_restart_components (argc, argv));
       
     case COM_RELOAD:
       exit (request_reload ());
 
     case COM_STATUS:
       exit (request_status ());
@@ -2099,17 +2095,17 @@ main (int argc, char **argv)
 
     case COM_DUMP_DEPMAP:
       components_dump_depmap ();
       exit (0);
 
     case COM_TRACE_DEPEND:
-      components_trace (argv + index, depmap_row);
+      components_trace (argv, depmap_row);
       exit (0);
       
     case COM_TRACE_PREREQ: 
-      components_trace (argv + index, depmap_col);
+      components_trace (argv, depmap_col);
       exit (0);
       
     default:
       pies_priv_setup (&pies_privs);
       if (pies_umask)
 	umask (pies_umask);
diff --git a/src/pies.h b/src/pies.h
index bcce32a..4a6160f 100644
--- a/src/pies.h
+++ b/src/pies.h
@@ -288,13 +288,12 @@ extern char **mailer_argv;
 extern size_t default_max_rate;
 extern char *qotdfile;
 
 extern int init_process;
 extern char *console_device;
 extern int initdefault;
-extern int dfl_level;
 
 extern size_t pies_master_argc;
 extern char **pies_master_argv;
 extern char *default_control_url[2];
 
 enum config_syntax_type
@@ -520,12 +519,13 @@ int sysvinit_sigtrans (int sig, int *pact);
 void sysvinit_runlevel_setup (int mask);
 void sysvinit_sysdep_begin (void);
 void sysvinit_power (void);
 
 void sysvinit_report (struct json_value *obj);
 int sysvinit_set_runlevel (int newlevel);
+void sysvinit_parse_argv (int argc, char **argv);
 
 extern char *sysvinit_environ_hint[];
 extern char *init_fifo;
 
 #ifndef INIT_FIFO
 # define INIT_FIFO  "/dev/initctl"
diff --git a/src/progman.c b/src/progman.c
index 8a5187c..1be7d27 100644
--- a/src/progman.c
+++ b/src/progman.c
@@ -1202,13 +1202,13 @@ prog_start (struct prog *prog)
       FD_SET (2, &fdset);
       if (prog->v.p.comp->mode == pies_comp_pass_fd)
 	FD_SET (prog->v.p.socket, &fdset);
       close_fds (&fdset);
 
       prog_execute (prog);
-
+      
       
     case -1:
       logmsg (LOG_CRIT,
 		      _("cannot run `%s': fork failed: %s"),
 	      prog_tag (prog), strerror (errno));
       break;
@@ -1543,12 +1543,15 @@ progman_wake_sleeping (int onalrm)
   debug (1, (_("checking for components to start")));
 
   for (prog = proghead; prog; prog = prog->next)
     {
       if (IS_ACTIVE_COMPONENT (prog) && prog->v.p.wait)
 	{
+	  /* The following works on the assumption that prog->v.p.wait is
+	     set when enabling the component and gets cleared right after
+	     it has finished. */
 	  if (prog->v.p.status != status_running)
 	    prog_start (prog);
 	  return;
 	}
     }
 
@@ -2408,7 +2411,8 @@ progman_stop_component (struct prog **progptr)
 void
 progman_stop_tag (const char *name)
 {
   struct prog *prog = progman_locate (name);
   progman_stop_component (&prog);
 }
+
 /* EOF */
diff --git a/src/sysvinit.c b/src/sysvinit.c
index 2d0671c..0370fcc 100644
--- a/src/sysvinit.c
+++ b/src/sysvinit.c
@@ -13,12 +13,13 @@
 
    You should have received a copy of the GNU General Public License
    along with GNU Pies.  If not, see <http://www.gnu.org/licenses/>. */
 
 #include "pies.h"
 #include "prog.h"
+#include <sys/ioctl.h>
 #include <termios.h>
 
 enum boot_state
   {
     sysinit,
     boot,
@@ -56,18 +57,19 @@ static int boot_trans_tab[max_boot_state][sizeof(valid_runlevels)-1]  = {
 enum boot_state boot_state;
 int runlevel = 0;
 int prevlevel = 'N';
 
 int initdefault;               /* Default runlevel */
 int dfl_level;
+int emergency_shell;
 
 int
 console_open (int mode)
 {
   int i, fd;
-  
+
   for (i = 0; i < 5; i++)
     {
       fd = open (console_device, mode | O_NONBLOCK);
       if (fd >= 0)
         {
           fcntl (fd, F_SETFL, mode);
@@ -643,12 +645,62 @@ unintr_sleep (unsigned n)
   tv.tv_usec = 0;
 
   while (select (0, NULL, NULL, NULL, &tv) < 0 && errno == EINTR)
     ;
 }
 
+static void
+start_shell (const char *shell)
+{
+  pid_t pid, rc;
+  int st;
+  struct sigaction act, old;
+
+  act.sa_flags = SA_RESTART;
+  act.sa_handler = SIG_DFL;
+  sigemptyset (&act.sa_mask);
+  sigaction (SIGCHLD, &act, &old);
+
+  pid = fork ();
+  if (pid == -1)
+    {
+      logmsg (LOG_CRIT, "cannot run `%s': fork failed: %s",
+	      shell, strerror (errno));
+      exit (1);
+    }
+
+  if (pid == 0)
+    {
+      int fd;
+
+      signal_setup (SIG_DFL);
+      setsid ();
+      
+      fd = console_open (O_RDWR|O_NOCTTY);
+      if (fd < 0) 
+	{
+	  logmsg (LOG_CRIT, "open(%s): %s",
+		  console_device, strerror (errno));
+	  exit (1);
+	}
+      ioctl (fd, TIOCSCTTY, 1);
+      dup (fd);
+      dup (fd);
+
+      execl (shell, shell, NULL);
+      _exit (127);
+    }
+  
+  while ((rc = wait (&st)) != pid)
+    if (rc == (pid_t) -1 && errno == ECHILD)
+      break;
+  
+  logmsg (LOG_CRIT, "shell finished");
+  sigaction (SIGCHLD, &old, NULL);
+}
+
 /* Memory allocation functions for INIT.  They may not fail, therefore
    they just retry allocation until it eventually succeeds.
 */
 
 static void *
 sysvinit_malloc (size_t size)
@@ -695,12 +747,14 @@ sysvinit_begin ()
   console_stty ();
   setsid ();
   envsetup ();
   sysvinit_runlevel_setup (PIES_COMP_DEFAULT);
   add_extra_sigv (sigv, ARRAY_SIZE (sigv));
   sysvinit_sysdep_begin ();
+  if (emergency_shell)
+    start_shell ("/sbin/sulogin");
 }
 
 #define IS_RUNNING_DISABLED_PROG(prog)		       \
   (IS_COMPONENT (prog)				       \
    && prog->v.p.status == status_running	       \
    && prog->v.p.comp->flags & CF_DISABLED)	       \
@@ -1137,6 +1191,22 @@ sysvinit_report (struct json_value *obj)
   json_object_set_string (obj, "bootstate", "%s",
 			  boot_state_name[boot_state]);
   if (initdefault)
     json_object_set_string (obj, "initdefault", "%c",
 			    initdefault);
 }
+
+void
+sysvinit_parse_argv (int argc, char **argv)
+{
+  while (--argc)
+    {
+      int c;
+      char *arg = *++argv;
+      if (!strcmp (arg, "single") || !strcmp (arg, "-s"))
+	dfl_level = 'S';
+      else if (!strcmp (arg, "-b") || !strcmp (arg, "emergency"))
+	emergency_shell = 1;
+      else if (!arg[1] && strchr (valid_runlevels, (c = toupper (arg[0]))))
+	dfl_level = c;
+    }	  
+}