[PATCH 4/9] Introduce container dump function

Andrey Mirkin
2008-09-03T10:56:22Z

Actually right now we are going to dump only one process.
Function for dumping head of image file are added.

Signed-off-by: Andrey Mirkin <major@openvz.org>
---
cpt/Makefile | 2 +-
cpt/checkpoint.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
cpt/cpt.h | 3 ++
cpt/sys.c | 3 +-
kernel/fork.c | 2 +
5 files changed, 82 insertions(+), 2 deletions(-)
create mode 100644 cpt/checkpoint.c

diff --git a/cpt/Makefile b/cpt/Makefile
index bfe75d5..173346b 100644
--- a/cpt/Makefile
+++ b/cpt/Makefile
@@ -2,4 +2,4 @@ obj-y += sys_core.o

obj-$(CONFIG_CHECKPOINT) += cptrst.o

-cptrst-objs := sys.o
+cptrst-objs := sys.o checkpoint.o
diff --git a/cpt/checkpoint.c b/cpt/checkpoint.c
new file mode 100644
index 0000000..b4d9686
--- /dev/null
+++ b/cpt/checkpoint.c
@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2008 Parallels, Inc.
+ *
+ * Author: Andrey Mirkin <major@openvz.org>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, version 2 of the
+ * License.
+ *
+ */
+
+#include <linux/sched.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/version.h>
+
+#include "cpt.h"
+
+static int cpt_write_head(struct cpt_context *ctx)
+{
+ struct cpt_head hdr;
+
+ memset(&hdr, 0, sizeof(hdr));
+ hdr.cpt_signature[0] = CPT_SIGNATURE0;
+ hdr.cpt_signature[1] = CPT_SIGNATURE1;
+ hdr.cpt_signature[2] = CPT_SIGNATURE2;
+ hdr.cpt_signature[3] = CPT_SIGNATURE3;
+ hdr.cpt_hdrlen = sizeof(hdr);
+ hdr.cpt_image_major = (LINUX_VERSION_CODE >> 16) & 0xff;
+ hdr.cpt_image_minor = (LINUX_VERSION_CODE >> 8) & 0xff;
+ hdr.cpt_image_sublevel = (LINUX_VERSION_CODE) & 0xff;
+ hdr.cpt_image_extra = 0;
+#if defined(CONFIG_X86_32)
+ hdr.cpt_arch = CPT_ARCH_I386;
+#else
+#error Arch is not supported
+#endif
+ return ctx->write(&hdr, sizeof(hdr), ctx);
+}
+
+int dump_container(struct cpt_context *ctx)
+{
+ int err;
+ struct task_struct *root;
+
+ read_lock(&tasklist_lock);
+ root = find_task_by_vpid(ctx->pid);
+ if (root)
+ get_task_struct(root);
+ read_unlock(&tasklist_lock);
+
+ err = -ESRCH;
+ if (!root) {
+ eprintk("can not find root task\n");
+ return err;
+ }
+ ctx->nsproxy = root->nsproxy;
+ if (!ctx->nsproxy) {
+ eprintk("nsproxy is null\n");
+ goto out;
+ }
+
+ err = cpt_write_head(ctx);
+
+ /* Dump task here */
+ if (!err)
+ err = -ENOSYS;
+
+out:
+ ctx->nsproxy = NULL;
+ put_task_struct(root);
+ return err;
+}
diff --git a/cpt/cpt.h b/cpt/cpt.h
index 607ac1b..b421a11 100644
--- a/cpt/cpt.h
+++ b/cpt/cpt.h
@@ -33,6 +33,7 @@ typedef struct cpt_context
int refcount;
int ctx_state;
struct semaphore main_sem;
+ struct nsproxy *nsproxy;

int errno;

@@ -54,3 +55,5 @@ extern int debug_level;

#define eprintk(a...) cpt_printk(1, "CPT ERR: " a)
#define dprintk(a...) cpt_printk(1, "CPT DBG: " a)
+
+int dump_container(struct cpt_context *ctx);
diff --git a/cpt/sys.c b/cpt/sys.c
index 8334c4c..6801c22 100644
--- a/cpt/sys.c
+++ b/cpt/sys.c
@@ -109,9 +109,10 @@ static int checkpoint(pid_t pid, int fd, unsigned long flags)

ctx->file = file;
ctx->ctx_state = CPT_CTX_DUMPING;
+ ctx->pid = pid;

/* checkpoint */
- err = -ENOSYS;
+ err = dump_container(ctx);

context_put(ctx);

diff --git a/kernel/fork.c b/kernel/fork.c
index 52b5037..f38b43d 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -77,6 +77,7 @@ int max_threads; /* tunable limit on nr_threads */
DEFINE_PER_CPU(unsigned long, process_counts) = 0;

__cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */
+EXPORT_SYMBOL(tasklist_lock);

int nr_processes(void)
{
@@ -153,6 +154,7 @@ void __put_task_struct(struct task_struct *tsk)
if (!profile_handoff_task(tsk))
free_task(tsk);
}
+EXPORT_SYMBOL(__put_task_struct);

/*
* macro override instead of weak attribute alias, to workaround
--
1.5.6