init: add FEATURE_KILL_REMOVED (Eugene Bordenkircher <eugebo@gmail.com>)

init: slight size optimization

2 files changed, 74 insertions, 63 deletions

diff --git a/init/Config.in b/init/Config.in
index 318f523a0..1084de905 100644
--- a/init/Config.in
+++ b/init/Config.in
@@ -27,6 +27,26 @@ config FEATURE_USE_INITTAB
         help
           Allow init to read an inittab file when the system boot.
 
+config FEATURE_KILL_REMOVED
+        bool "Support killing processes that have been removed from inittab"
+        default y
+        depends on FEATURE_USE_INITTAB
+        help
+          When respawn entries are removed from inittab and a SIGHUP is 
+          sent to init, this feature will kill the processes that have 
+          been removed.
+
+config FEATURE_KILL_DELAY
+        int "How long to wait between TERM and KILL (0 - send TERM only)"
+        range 0 1024
+        default 0
+        depends on FEATURE_KILL_REMOVED
+        help
+          With nonzero setting, init sends TERM, forks, child waits N
+          seconds, sends KILL and exits. Setting it too high is unwise
+          (child will hang around for too long and can actually kill
+          wrong process!)
+
 config FEATURE_INIT_SCTTY
         bool "Support running commands with a controlling-tty"
         default n
diff --git a/init/init.c b/init/init.c
index baa5a5000..e6581880c 100644
--- a/init/init.c
+++ b/init/init.c
@@ -738,21 +738,8 @@ static void delete_init_action(struct init_action *action)
 static void parse_inittab(void)
 {
 #if ENABLE_FEATURE_USE_INITTAB
-        static const char actions[] =
-                STR_SYSINIT    "sysinit\0"
-                STR_RESPAWN    "respawn\0"
-                STR_ASKFIRST   "askfirst\0"
-                STR_WAIT       "wait\0"
-                STR_ONCE       "once\0"
-                STR_CTRLALTDEL "ctrlaltdel\0"
-                STR_SHUTDOWN   "shutdown\0"
-                STR_RESTART    "restart\0"
-        ;
-
         FILE *file;
-        char buf[INIT_BUFFS_SIZE], lineAsRead[INIT_BUFFS_SIZE];
-        char tmpConsole[CONSOLE_NAME_SIZE];
-        char *id, *runlev, *action, *command, *eol;
+        char buf[INIT_BUFFS_SIZE];
 
         file = fopen(INITTAB, "r");
         if (file == NULL) {
@@ -780,57 +767,43 @@ static void parse_inittab(void)
         }
 
         while (fgets(buf, INIT_BUFFS_SIZE, file) != NULL) {
+                static const char actions[] =
+                        STR_SYSINIT    "sysinit\0"
+                        STR_RESPAWN    "respawn\0"
+                        STR_ASKFIRST   "askfirst\0"
+                        STR_WAIT       "wait\0"
+                        STR_ONCE       "once\0"
+                        STR_CTRLALTDEL "ctrlaltdel\0"
+                        STR_SHUTDOWN   "shutdown\0"
+                        STR_RESTART    "restart\0"
+                ;
+                char tmpConsole[CONSOLE_NAME_SIZE];
+                char *id, *runlev, *action, *command;
                 const char *a;
 
                 /* Skip leading spaces */
-                for (id = buf; *id == ' ' || *id == '\t'; id++);
-
+                id = skip_whitespace(buf);
                 /* Skip the line if it's a comment */
                 if (*id == '#' || *id == '\n')
                         continue;
+                /* Trim the trailing '\n' */
+                *strchrnul(id, '\n') = '\0';
 
-                /* Trim the trailing \n */
-                //XXX: chomp() ?
-                eol = strrchr(id, '\n');
-                if (eol != NULL)
-                        *eol = '\0';
-
-                /* Keep a copy around for posterity's sake (and error msgs) */
-                strcpy(lineAsRead, buf);
-
-                /* Separate the ID field from the runlevels */
+                /* Line is: "id:runlevel_ignored:action:command" */
                 runlev = strchr(id, ':');
-                if (runlev == NULL || *(runlev + 1) == '\0') {
-                        message(L_LOG | L_CONSOLE, "Bad inittab entry: %s", lineAsRead);
-                        continue;
-                } else {
-                        *runlev = '\0';
-                        ++runlev;
-                }
-
-                /* Separate the runlevels from the action */
-                action = strchr(runlev, ':');
-                if (action == NULL || *(action + 1) == '\0') {
-                        message(L_LOG | L_CONSOLE, "Bad inittab entry: %s", lineAsRead);
-                        continue;
-                } else {
-                        *action = '\0';
-                        ++action;
-                }
-
-                /* Separate the action from the command */
-                command = strchr(action, ':');
-                if (command == NULL || *(command + 1) == '\0') {
-                        message(L_LOG | L_CONSOLE, "Bad inittab entry: %s", lineAsRead);
-                        continue;
-                } else {
-                        *command = '\0';
-                        ++command;
-                }
-
-                /* Ok, now process it */
+                if (runlev == NULL /*|| runlev[1] == '\0' - not needed */)
+                        goto bad_entry;
+                action = strchr(runlev + 1, ':');
+                if (action == NULL /*|| action[1] == '\0' - not needed */)
+                        goto bad_entry;
+                command = strchr(action + 1, ':');
+                if (command == NULL || command[1] == '\0')
+                        goto bad_entry;
+
+                *command = '\0'; /* action => ":action\0" now */
                 for (a = actions; a[0]; a += strlen(a) + 1) {
-                        if (strcmp(a + 1, action) == 0) {
+                        if (strcmp(a + 1, action + 1) == 0) {
+                                *runlev = '\0';
                                 if (*id != '\0') {
                                         if (strncmp(id, "/dev/", 5) == 0)
                                                 id += 5;
@@ -839,14 +812,15 @@ static void parse_inittab(void)
                                                 sizeof(tmpConsole) - 5);
                                         id = tmpConsole;
                                 }
-                                new_init_action((uint8_t)a[0], command, id);
-                                break;
+                                new_init_action((uint8_t)a[0], command + 1, id);
+                                goto next_line;
                         }
                 }
-                if (!a[0]) {
-                        /* Choke on an unknown action */
-                        message(L_LOG | L_CONSOLE, "Bad inittab entry: %s", lineAsRead);
-                }
+                *command = ':';
+                /* Choke on an unknown action */
+ bad_entry:
+                message(L_LOG | L_CONSOLE, "Bad inittab entry: %s", id);
+ next_line: ;
         }
         fclose(file);
 #endif /* FEATURE_USE_INITTAB */
@@ -860,12 +834,29 @@ static void reload_signal(int sig ATTRIBUTE_UNUSED)
         message(L_LOG, "reloading /etc/inittab");
 
         /* disable old entrys */
-        for (a = init_action_list; a; a = a->next ) {
+        for (a = init_action_list; a; a = a->next) {
                 a->action = ONCE;
         }
 
         parse_inittab();
 
+#if ENABLE_FEATURE_KILL_REMOVED
+        for (a = init_action_list; a; a = a->next) {
+                pid_t pid = a->pid;
+                if ((a->action & ONCE) && pid != 0) {
+                        /* Be nice and send SIGTERM first */
+                        kill(pid, SIGTERM);
+#if CONFIG_FEATURE_KILL_DELAY
+                        if (fork() == 0) { /* child */
+                                sleep(CONFIG_FEATURE_KILL_DELAY);
+                                kill(pid, SIGKILL);
+                                _exit(0);
+                        }
+#endif
+                }
+        }
+#endif /* FEATURE_KILL_REMOVED */
+
         /* remove unused entrys */
         for (a = init_action_list; a; a = tmp) {
                 tmp = a->next;