On Friday 04 April 2008 22:40, Harald Kuethe wrote:
> The first part is with a vfork() call in static pid_t run(const struct
> init_action *a)
> the second part uses fork()
>
> Freeing unused kernel memory: 68k init
> *Start init_main
> init: waiting for 10
> *console_init
> init started
> init started: BusyBox v1.10.0 (2008-04-01 22:01:03 CEST)
> *single?
> *run_actions
> init: before waitfor(run(a))
> init: run vfork returned 0
> init: run vfork returned 11
> *call bb_signals
> init: waiting for 11
>
> ...
>
> init: after waitfor(run(a))
> *signals
> *RESPAWN
> *ASKFIRST
> init: before a->pid = run(a)
> init: run vfork returned 0
>
> Please press Enter to activate this console.
> init: run vfork returned 80
if (BB_MMU && (a->action_type & ASKFIRST)) {
static const char press_enter[] ALIGN1 =
#ifdef CUSTOMIZED_BANNER
#include CUSTOMIZED_BANNER
#endif
"\nPlease press Enter to activate this console. ";
char c;
/*
* Save memory by not exec-ing anything large (like a shell)
* before the user wants it. This is critical if swap is not
* enabled and the system has low memory. Generally this will
* be run on the second virtual console, and the first will
* be allowed to start a shell or whatever an init script
* specifies.
*/
messageD(L_LOG, "waiting for enter to start '%s'"
"(pid %d, tty '%s')\n",
a->command, getpid(), a->terminal);
full_write(1, press_enter, sizeof(press_enter) - 1);
while (safe_read(0, &c, 1) == 1 && c != '\n')
continue;
}
DOH!
Try this patch.
--
vda
diff -d -urpN busybox.9/init/init.c busybox.a/init/init.c
--- busybox.9/init/init.c 2008-03-31 21:26:19.000000000 +0200
+++ busybox.a/init/init.c 2008-04-05 06:22:35.000000000 +0200
@@ -33,14 +33,15 @@
#endif
/* Allowed init action types */
-#define SYSINIT 0x001
-#define RESPAWN 0x002
-#define ASKFIRST 0x004
-#define WAIT 0x008
-#define ONCE 0x010
-#define CTRLALTDEL 0x020
-#define SHUTDOWN 0x040
-#define RESTART 0x080
+#define SYSINIT 0x01
+#define RESPAWN 0x02
+/* like respawn, but wait for <Enter> to be pressed on tty: */
+#define ASKFIRST 0x04
+#define WAIT 0x08
+#define ONCE 0x10
+#define CTRLALTDEL 0x20
+#define SHUTDOWN 0x40
+#define RESTART 0x80
#define STR_SYSINIT "\x01"
#define STR_RESPAWN "\x02"
@@ -372,7 +373,10 @@ static pid_t run(const struct init_actio
sigemptyset(&nmask);
sigaddset(&nmask, SIGCHLD);
sigprocmask(SIG_BLOCK, &nmask, &omask);
- pid = vfork();
+ if (BB_MMU && (a->action_type & ASKFIRST))
+ pid = fork();
+ else
+ pid = vfork();
sigprocmask(SIG_SETMASK, &omask, NULL);
if (pid < 0)
@@ -447,7 +451,8 @@ static pid_t run(const struct init_actio
}
#endif
- /* NB: on NOMMU we can't wait for input in child */
+ /* NB: on NOMMU we can't wait for input in child, so
+ * "askfirst" will work the same as "respawn". */
if (BB_MMU && (a->action_type & ASKFIRST)) {
static const char press_enter[] ALIGN1 =
#ifdef CUSTOMIZED_BANNER
@@ -499,7 +504,7 @@ static void run_actions(int action_type)
for (a = init_action_list; a; a = tmp) {
tmp = a->next;
- if (a->action_type == action_type) {
+ if (a->action_type & action_type) {
// Pointless: run() will error out if open of device fails.
///* a->terminal of "" means "init's console" */
//if (a->terminal[0] && access(a->terminal, R_OK | W_OK)) {
@@ -784,6 +789,7 @@ static void parse_inittab(void)
fclose(file);
}
+#if ENABLE_FEATURE_USE_INITTAB
static void reload_signal(int sig ATTRIBUTE_UNUSED)
{
struct init_action *a, *tmp;
@@ -827,8 +833,9 @@ static void reload_signal(int sig ATTRIB
delete_init_action(a);
}
}
- run_actions(RESPAWN);
+ run_actions(RESPAWN | ASKFIRST);
}
+#endif
int init_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int init_main(int argc ATTRIBUTE_UNUSED, char **argv)
@@ -952,18 +959,16 @@ int init_main(int argc ATTRIBUTE_UNUSED,
run_actions(ONCE);
/* Redefine SIGHUP to reread /etc/inittab */
- if (ENABLE_FEATURE_USE_INITTAB)
- signal(SIGHUP, reload_signal);
- else
- signal(SIGHUP, SIG_IGN);
+#if ENABLE_FEATURE_USE_INITTAB
+ signal(SIGHUP, reload_signal);
+#else
+ signal(SIGHUP, SIG_IGN);
+#endif
/* Now run the looping stuff for the rest of forever */
while (1) {
- /* run the respawn stuff */
- run_actions(RESPAWN);
-
- /* run the askfirst stuff */
- run_actions(ASKFIRST);
+ /* run the respawn/askfirst stuff */
+ run_actions(RESPAWN | ASKFIRST);
/* Don't consume all CPU time -- sleep a bit */
sleep(1);
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