[Devel] [PATCH] restart: add switch '--self' for self-restart

[Oren Laadan]

There is no reason to keep a separate program for self-restart.
Get rid of self_restart.c

Signed-off-by: Oren Laadan <orenl at cs.columbia.edu>
---
 Makefile       |    7 +++----
 restart.c      |   25 +++++++++++++++++++++++--
 self_restart.c |   35 -----------------------------------
 3 files changed, 26 insertions(+), 41 deletions(-)
 delete mode 100644 self_restart.c

diff --git a/Makefile b/Makefile
index 830e2c8..7f5cb27 100644
--- a/Makefile
+++ b/Makefile
@@ -35,7 +35,7 @@ CFLAGS += -g $(WARNS) $(CKPT_INCLUDE) $(DEBUG)
 # install dir
 INSTALL_DIR = /bin
 
-PROGS =	self_checkpoint self_restart checkpoint restart ckptinfo
+PROGS =	checkpoint restart ckptinfo
 
 # other cleanup
 OTHER = ckptinfo_types.c
@@ -43,7 +43,6 @@ OTHER = ckptinfo_types.c
 LDLIBS = -lm
 
 all: $(PROGS)
-	echo $(SUBARCH)
 	@make -C test
 
 # restart needs to be thread-safe
@@ -68,8 +67,8 @@ ckptinfo_types.c: $(CKPT_HEADERS) ckptinfo.py
 	@cat $(CKPT_HEADERS) | ./ckptinfo.py > ckptinfo_types.c
 
 install:
-	@echo /usr/bin/install -m 755 checkpoint restart self_restart ckptinfo $(INSTALL_DIR)
-	@/usr/bin/install -m 755 checkpoint restart self_restart ckptinfo $(INSTALL_DIR)
+	@echo /usr/bin/install -m 755 checkpoint restart ckptinfo $(INSTALL_DIR)
+	@/usr/bin/install -m 755 checkpoint restart ckptinfo $(INSTALL_DIR)
 
 clean:
 	@rm -f $(PROGS) $(OTHER) *~ *.o
diff --git a/restart.c b/restart.c
index 600a282..c0d52a5 100644
--- a/restart.c
+++ b/restart.c
@@ -63,6 +63,7 @@ static char usage_str[] =
 "  -p,--pidns            create a new pid namspace (default with --pids)\n"
 "  -P,--no-pidns         do not create a new pid namespace (default)\n"
 "     --pids             restore original pids (default with --pidns)\n"
+"     --self             restart a single task, usually from self-checkpoint\n"
 "  -r,--root=ROOT        restart under the directory ROOT instead of current\n"
 "     --signal=SIG       send SIG to root task on SIGINT (default: SIGKILL\n"
 "                        to container root, SIGINT otherwise)\n"
@@ -335,6 +336,7 @@ struct pid_swap {
 };
 
 struct args {
+	int self;
 	int pids;
 	int pidns;
 	int no_pidns;
@@ -372,6 +374,7 @@ static void parse_args(struct args *args, int argc, char *argv[])
 		{ "pidns",	no_argument,		NULL, 'p' },
 		{ "no-pidns",	no_argument,		NULL, 'P' },
 		{ "pids",	no_argument,		NULL, 3 },
+		{ "self",	no_argument,		NULL, 6},
 		{ "signal",	required_argument,	NULL, 4 },
 		{ "inspect",	no_argument,		NULL, 5 },
 		{ "input",	required_argument,		NULL, 'i' },
@@ -417,6 +420,9 @@ static void parse_args(struct args *args, int argc, char *argv[])
 		case 'P':
 			args->no_pidns = 1;
 			break;
+		case 6:  /* --self */
+			args->self = 1;
+			break;
 		case 4:  /* --signal */
 			sig = str2sig(optarg);
 			if (sig < 0)
@@ -488,6 +494,13 @@ static void parse_args(struct args *args, int argc, char *argv[])
 		exit(1);
 	}
 #endif
+
+	if (args->self &&
+	    (args->pids || args->pidns || args->no_pidns || args->wait ||
+	     args->show_status || args->copy_status || args->freezer)) {
+		printf("Invalid mix of --self with multiprocess options\n");
+		exit(1);
+	}
 }
 
 static void report_exit_status(int status, char *str, int debug)
@@ -650,14 +663,22 @@ int main(int argc, char *argv[])
 	if (args.freezer && freezer_prepare(&ctx) < 0)
 		exit(1);
 
-	setpgrp();
-
 	/* chroot ? */
 	if (args.root && chroot(args.root) < 0) {
 		perror("chroot");
 		exit(1);
 	}
 
+	/* self-restart ends here: */
+	if (args.self) {
+		restart(getpid(), STDIN_FILENO, RESTART_TASKSELF);
+		/* reach here if restart(2) failed ! */
+		perror("restart");
+		exit(1);
+	}
+
+	setpgrp();
+
 	ret = ckpt_read_header(&ctx);
 	if (ret < 0) {
 		perror("read c/r header");
diff --git a/self_restart.c b/self_restart.c
deleted file mode 100644
index b0fbaab..0000000
--- a/self_restart.c
+++ /dev/null
@@ -1,35 +0,0 @@
-/*
- *  self_restart.c: restart a single process
- *
- *  Copyright (C) 2008 Oren Laadan
- *
- *  This file is subject to the terms and conditions of the GNU General Public
- *  License.  See the file COPYING in the main directory of the Linux
- *  distribution for more details.
- */
-
-#define _GNU_SOURCE        /* or _BSD_SOURCE or _SVID_SOURCE */
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <errno.h>
-#include <fcntl.h>
-#include <unistd.h>
-#include <asm/unistd.h>
-#include <sys/syscall.h>
-
-#include <linux/checkpoint.h>
-
-int main(int argc, char *argv[])
-{
-	pid_t pid = getpid();
-	int ret;
-
-	ret = syscall(__NR_restart, pid, STDIN_FILENO, RESTART_TASKSELF);
-	if (ret < 0)
-		perror("restart");
-
-	printf("should not reach here !\n");
-
-	return 0;
-}
-- 
1.6.0.4

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