System-wide init family awareness

src/boot.c

@@ -187,8 +187,9 @@ int internal_boot(struct ds_config *cfg) {
     return -1;
   }
 
-  /* Detect init system once - used for seccomp and cgroup setup */
-  int is_systemd = is_systemd_rootfs(cfg->rootfs_path);
+  /* Init family was classified before fork in start_rootfs().
+   * Boot-time setup only needs to know whether that family is systemd. */
+  int is_systemd = (cfg->init_type == DS_INIT_SYSTEMD);
 
   /* 3. Setup volatile overlay INSIDE the container's mount namespace.
    * This MUST happen here (not in parent) so the overlay's connection to

src/container.c

@@ -224,6 +224,7 @@ static void cleanup_container_resources(struct ds_config *cfg, pid_t pid,
    * so start_rootfs() can detect the existing mount and reuse it. */
   if (!skip_unmount) {
     remove_mount_path(cfg->pidfile);
+    remove_init_type(cfg->pidfile);
     if (cfg->pidfile[0])
       unlink(cfg->pidfile);
     if (global_pidfile[0] && strcmp(cfg->pidfile, global_pidfile) != 0)
@@ -436,6 +437,11 @@ int start_rootfs(struct ds_config *cfg) {
         unmount_rootfs_img(cfg->img_mount_point, cfg->foreground);
       return -1;
     }
+
+    /* Classify the container init family while the normalized host rootfs
+     * path is already in scope. Detecting here avoids rebuilding the same
+     * probe path later solely for shutdown metadata. */
+    cfg->init_type = detect_container_init(rootfs_norm);
   }
 
   /* 2b. Android Termux Bridge Preparation - only if flag is set */
@@ -1136,6 +1142,9 @@ int start_rootfs(struct ds_config *cfg) {
   if (cfg->is_img_mount)
     save_mount_path(cfg->pidfile, cfg->img_mount_point);
 
+  /* Also save init type */
+  save_init_type(cfg->pidfile, cfg->init_type);
+
   /* 11. Foreground or background finish */
   if (cfg->foreground) {
 
@@ -1261,8 +1270,13 @@ int stop_rootfs(struct ds_config *cfg, int skip_unmount) {
   ds_init_type_t init_type = DS_INIT_UNKNOWN;
   const char *probe_root =
       cfg->img_mount_point[0] ? cfg->img_mount_point : cfg->rootfs_path;
-  if (probe_root[0])
-    init_type = detect_container_init(probe_root);
+  if (__builtin_expect( (read_init_type(cfg->pidfile, &init_type) != 0 ||
+    init_type == DS_INIT_UNKNOWN), 0)) {
+    /* Fallback for containers launched before .init sidecars existed,
+     * or if runtime metadata was lost / non-informative. */
+    if (__builtin_expect(probe_root[0], '/'))
+      init_type = detect_container_init(probe_root);
+  }
 
   switch (init_type) {
   case DS_INIT_PROCD:

src/droidspace.h

@@ -128,6 +128,7 @@
 #define DS_EXT_PID ".pid"
 #define DS_EXT_MOUNT ".mount"
 #define DS_EXT_LOCK ".lock"
+#define DS_EXT_INIT ".init"
 
 /* Signals */
 #define DS_SIG_STOP (SIGRTMIN + 3)
@@ -271,6 +272,17 @@ struct ds_port_forward {
                              */
 #define DS_PRIV_FULL (0xFF) /* All above */
 
+typedef enum {
+  DS_INIT_UNKNOWN = 0,
+  DS_INIT_SYSTEMD,  /* SIGRTMIN+3 */
+  DS_INIT_PROCD,    /* SIGUSR2    -- OpenWrt; SIGTERM = reboot there! */
+  DS_INIT_OPENRC,   /* SIGTERM    */
+  DS_INIT_RUNIT,    /* SIGCONT    */
+  DS_INIT_S6,       /* SIGUSR2    */
+  DS_INIT_BUSYBOX,  /* SIGUSR2    */
+  DS_INIT_SYSVINIT, /* SIGTERM    */
+} ds_init_type_t;
+
 struct ds_config {
   /* Paths */
   char rootfs_path[PATH_MAX];     /* --rootfs=  */
@@ -309,6 +321,7 @@ struct ds_config {
   pid_t intermediate_pid;         /* intermediate fork pid */
   int is_img_mount;               /* 1 if rootfs was loop-mounted from .img */
   char img_mount_point[PATH_MAX]; /* where the .img was mounted */
+  ds_init_type_t init_type;       /* detected container PID 1 init family */
 
   /* NAT networking synchronization pipes
    * Both pairs are initialised to {-1,-1} in main() after memset.
@@ -386,6 +399,9 @@ int read_and_validate_pid(const char *pidfile, pid_t *pid_out);
 int save_mount_path(const char *pidfile, const char *mount_path);
 int read_mount_path(const char *pidfile, char *buf, size_t size);
 int remove_mount_path(const char *pidfile);
+int save_init_type(const char *pidfile, ds_init_type_t init_type);
+int read_init_type(const char *pidfile, ds_init_type_t *init_type_out);
+int remove_init_type(const char *pidfile);
 void firmware_path_add(const char *fw_path);
 void firmware_path_remove(const char *fw_path);
 int run_command(char *const argv[]);
@@ -399,17 +415,6 @@ void print_ds_banner(void);
 void print_privileged_warning(int privileged_mask);
 int is_systemd_rootfs(const char *path);
 
-typedef enum {
-  DS_INIT_UNKNOWN = 0,
-  DS_INIT_SYSTEMD,  /* SIGRTMIN+3 */
-  DS_INIT_PROCD,    /* SIGUSR2    -- OpenWrt; SIGTERM = reboot there! */
-  DS_INIT_OPENRC,   /* SIGTERM    */
-  DS_INIT_RUNIT,    /* SIGCONT    */
-  DS_INIT_S6,       /* SIGUSR2    */
-  DS_INIT_BUSYBOX,  /* SIGUSR2    */
-  DS_INIT_SYSVINIT, /* SIGTERM    */
-} ds_init_type_t;
-
 ds_init_type_t detect_container_init(const char *path);
 int get_user_shell(const char *user, char *shell_buf, size_t size);
 void check_kernel_recommendation(void);

src/pid.c

@@ -221,6 +221,7 @@ int count_running_containers(char *first_name, size_t size) {
         /* Explicit pruning during scan */
         unlink(tmp_cfg.pidfile);
         remove_mount_path(tmp_cfg.pidfile);
+        remove_init_type(tmp_cfg.pidfile);
       }
     }
   }
@@ -437,6 +438,7 @@ int show_containers(void) {
         /* Explicit pruning during scan */
         unlink(tmp_cfg.pidfile);
         remove_mount_path(tmp_cfg.pidfile);
+        remove_init_type(tmp_cfg.pidfile);
       }
     }
   }
@@ -676,6 +678,7 @@ int scan_containers(void) {
         /* Stale PID file, nuke it */
         unlink(pf);
         remove_mount_path(pf);
+        remove_init_type(pf);
       }
     }
     closedir(d);

src/utils.c

@@ -714,6 +714,95 @@ int remove_mount_path(const char *pidfile) {
   return unlink(mpath);
 }
 
+/* ---------------------------------------------------------------------------
+ * Init-type sidecar files (.init)
+ * ---------------------------------------------------------------------------*/
+
+static void pidfile_to_initfile(const char *pidfile, char *buf, size_t size) {
+  safe_strncpy(buf, pidfile, size);
+  char *dot = strrchr(buf, '.');
+  if (dot && strcmp(dot, DS_EXT_PID) == 0) {
+    /* If it ends in .pid, replace it */
+    snprintf(dot, size - (size_t)(dot - buf), DS_EXT_INIT);
+  } else {
+    /* Otherwise just append */
+    strncat(buf, DS_EXT_INIT, size - strlen(buf) - 1);
+  }
+}
+
+static const char *init_type_to_string(ds_init_type_t type) {
+  switch (type) {
+  case DS_INIT_SYSTEMD:
+    return "systemd";
+  case DS_INIT_PROCD:
+    return "procd";
+  case DS_INIT_OPENRC:
+    return "openrc";
+  case DS_INIT_RUNIT:
+    return "runit";
+  case DS_INIT_S6:
+    return "s6";
+  case DS_INIT_BUSYBOX:
+    return "busybox";
+  case DS_INIT_SYSVINIT:
+    return "sysvinit";
+  case DS_INIT_UNKNOWN:
+  default:
+    return "unknown";
+  }
+}
+
+static ds_init_type_t init_type_from_string(const char *s) {
+  if (!s || s[0] == '\0')
+    return DS_INIT_UNKNOWN;
+
+  if (strcmp(s, "systemd") == 0)
+    return DS_INIT_SYSTEMD;
+  if (strcmp(s, "procd") == 0)
+    return DS_INIT_PROCD;
+  if (strcmp(s, "openrc") == 0)
+    return DS_INIT_OPENRC;
+  if (strcmp(s, "runit") == 0)
+    return DS_INIT_RUNIT;
+  if (strcmp(s, "s6") == 0)
+    return DS_INIT_S6;
+  if (strcmp(s, "busybox") == 0)
+    return DS_INIT_BUSYBOX;
+  if (strcmp(s, "sysvinit") == 0)
+    return DS_INIT_SYSVINIT;
+
+  return DS_INIT_UNKNOWN;
+}
+
+int save_init_type(const char *pidfile, ds_init_type_t init_type) {
+  char ipath[PATH_MAX];
+  pidfile_to_initfile(pidfile, ipath, sizeof(ipath));
+  return write_file(ipath, init_type_to_string(init_type));
+}
+
+int read_init_type(const char *pidfile, ds_init_type_t *init_type_out) {
+  if (!init_type_out)
+    return -1;
+
+  char ipath[PATH_MAX];
+  char buf[64];
+
+  pidfile_to_initfile(pidfile, ipath, sizeof(ipath));
+
+  if (read_file(ipath, buf, sizeof(buf)) < 0)
+    return -1;
+
+  buf[strcspn(buf, "\r\n")] = '\0';
+  *init_type_out = init_type_from_string(buf);
+  return 0;
+}
+
+int remove_init_type(const char *pidfile) {
+  char ipath[PATH_MAX];
+  pidfile_to_initfile(pidfile, ipath, sizeof(ipath));
+  return unlink(ipath);
+}
+
 /* ---------------------------------------------------------------------------
  * Kernel firmware search path management
  *