parasite: Dump misc command

Add command and basis for dumping minor bits for task
from parasite code. It's supposed to retrieve minor bits
form tasks which cannot be read from /proc.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>

cr-dump.c

@@ -6,6 +6,7 @@
 #include <unistd.h>
 #include <errno.h>
 #include <string.h>
+#include <parasite.h>
 
 #include <fcntl.h>
 
@@ -1142,6 +1143,7 @@ static int dump_one_task(struct pstree_item *item, struct cr_fdset *cr_fdset)
 	struct parasite_ctl *parasite_ctl;
 	int ret = -1;
 	int pid_dir;
+	struct parasite_dump_misc misc;
 
 	pr_info("========================================\n");
 	pr_info("Dumping task (pid: %d)\n", pid);
@@ -1217,6 +1219,12 @@ static int dump_one_task(struct pstree_item *item, struct cr_fdset *cr_fdset)
 		goto err;
 	}
 
+	ret = parasite_dump_misc_seized(parasite_ctl, &misc);
+	if (ret) {
+		pr_err("Can't dump misc (pid: %d)\n", pid);
+		goto err;
+	}
+
 	ret = parasite_cure_seized(parasite_ctl, &vma_area_list);
 	if (ret) {
 		pr_err("Can't cure (pid: %d) from parasite\n", pid);

include/parasite-syscall.h

@@ -41,6 +41,9 @@ extern int parasite_dump_pages_seized(struct parasite_ctl *ctl, struct list_head
 extern int parasite_dump_sigacts_seized(struct parasite_ctl *ctl, struct cr_fdset *cr_fdset);
 extern int parasite_dump_itimers_seized(struct parasite_ctl *ctl, struct cr_fdset *cr_fdset);
 
+struct parasite_dump_misc;
+extern int parasite_dump_misc_seized(struct parasite_ctl *ctl, struct parasite_dump_misc *);
+
 extern struct parasite_ctl *parasite_infect_seized(pid_t pid, struct list_head *vma_area_list);
 extern int parasite_cure_seized(struct parasite_ctl *ctl, struct list_head *vma_area_list);
 

include/parasite.h

@@ -35,6 +35,7 @@ enum {
 	PARASITE_CMD_DUMPPAGES,
 	PARASITE_CMD_DUMP_SIGACTS,
 	PARASITE_CMD_DUMP_ITIMERS,
+	PARASITE_CMD_DUMP_MISC,
 
 	PARASITE_CMD_MAX,
 };
@@ -73,6 +74,15 @@ struct parasite_dump_pages_args {
 	unsigned long		fd;
 };
 
+/*
+ * Misc sfuff, that is too small for separate file, but cannot
+ * be read w/o using parasite
+ */
+
+struct parasite_dump_misc {
+	parasite_status_t	status;
+};
+
 /*
  * Some useful offsets
  */

parasite-syscall.c

@@ -393,6 +393,12 @@ int parasite_dump_itimers_seized(struct parasite_ctl *ctl, struct cr_fdset *cr_f
 	return parasite_file_cmd(PARASITE_CMD_DUMP_ITIMERS, CR_FD_ITIMERS, ctl, cr_fdset);
 }
 
+int parasite_dump_misc_seized(struct parasite_ctl *ctl, struct parasite_dump_misc *misc)
+{
+	return parasite_execute(PARASITE_CMD_DUMP_MISC, ctl,
+			(parasite_status_t *)misc, sizeof(struct parasite_dump_misc));
+}
+
 /*
  * This routine drives parasite code (been previously injected into a victim
  * process) and tells it to dump pages into the file.

parasite.c

@@ -348,6 +348,14 @@ err_close:
 	return ret;
 }
 
+static int dump_misc(struct parasite_dump_misc *args)
+{
+	parasite_status_t *st = &args->status;
+
+	SET_PARASITE_STATUS(st, 0, 0);
+	return 0;
+}
+
 static int __used parasite_service(unsigned long cmd, void *args, void *brk)
 {
 	brk_init(brk);
@@ -367,6 +375,8 @@ static int __used parasite_service(unsigned long cmd, void *args, void *brk)
 		return dump_sigact((struct parasite_dump_file_args *)args);
 	case PARASITE_CMD_DUMP_ITIMERS:
 		return dump_itimers((struct parasite_dump_file_args *)args);
+	case PARASITE_CMD_DUMP_MISC:
+		return dump_misc((struct parasite_dump_misc *)args);
 	default:
 		sys_write_msg("Unknown command to parasite\n");
 		break;