kernel, dump: Obtain brk value

Also re-make image to be 2 pages in size
which should be enough for basic params we
need to restore tasks.
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>

cr-dump.c

@@ -547,6 +547,7 @@ static int dump_task_core_seized(pid_t pid, struct cr_fdset *cr_fdset)
 	user_regs_struct_t regs		= {-1};
 	int fd_core			= cr_fdset->desc[CR_FD_CORE].fd;
 	int ret				= -1;
+	unsigned long brk;
 
 	pr_info("\n");
 	pr_info("Dumping core (pid: %d)\n", pid);
@@ -590,14 +591,14 @@ static int dump_task_core_seized(pid_t pid, struct cr_fdset *cr_fdset)
 	assign_reg(core->u.arch.gpregs, regs,		fs);
 	assign_reg(core->u.arch.gpregs, regs,		gs);
 
-	assign_reg(core->u.arch.fpregs, fpregs,	cwd);
-	assign_reg(core->u.arch.fpregs, fpregs,	swd);
-	assign_reg(core->u.arch.fpregs, fpregs,	twd);
-	assign_reg(core->u.arch.fpregs, fpregs,	fop);
-	assign_reg(core->u.arch.fpregs, fpregs,	rip);
-	assign_reg(core->u.arch.fpregs, fpregs,	rdp);
-	assign_reg(core->u.arch.fpregs, fpregs,	mxcsr);
-	assign_reg(core->u.arch.fpregs, fpregs,	mxcsr_mask);
+	assign_reg(core->u.arch.fpregs, fpregs,		cwd);
+	assign_reg(core->u.arch.fpregs, fpregs,		swd);
+	assign_reg(core->u.arch.fpregs, fpregs,		twd);
+	assign_reg(core->u.arch.fpregs, fpregs,		fop);
+	assign_reg(core->u.arch.fpregs, fpregs,		rip);
+	assign_reg(core->u.arch.fpregs, fpregs,		rdp);
+	assign_reg(core->u.arch.fpregs, fpregs,		mxcsr);
+	assign_reg(core->u.arch.fpregs, fpregs,		mxcsr_mask);
 
 	assign_array(core->u.arch.fpregs, fpregs,	st_space);
 	assign_array(core->u.arch.fpregs, fpregs,	xmm_space);
@@ -623,6 +624,13 @@ static int dump_task_core_seized(pid_t pid, struct cr_fdset *cr_fdset)
 		goto err_free;
 	pr_info("OK\n");
 
+	pr_info("Obtainting task brk ... ");
+	brk = brk_seized(pid, 0);
+	if ((long)brk < 0)
+		goto err_free;
+	core->mm_brk = brk;
+	pr_info("OK\n");
+
 	pr_info("Dumping header ... ");
 	core->header.version	= HEADER_VERSION;
 	core->header.arch	= HEADER_ARCH_X86_64;

cr-show.c

@@ -107,6 +107,7 @@ static void show_core_rest(struct cr_fdset *cr_fdset)
 	int fd_core, i;
 	u32 personality;
 	char comm[TASK_COMM_LEN];
+	u64 mm_brk;
 
 	fd_core = cr_fdset->desc[CR_FD_CORE].fd;
 	if (fd_core < 0)
@@ -118,8 +119,12 @@ static void show_core_rest(struct cr_fdset *cr_fdset)
 	lseek(fd_core, GET_FILE_OFF(struct core_entry, task_comm), SEEK_SET);
 	read_safe(fd_core, comm, TASK_COMM_LEN, err);
 
+	lseek(fd_core, GET_FILE_OFF(struct core_entry, mm_brk), SEEK_SET);
+	read_ptr_safe(fd_core, &mm_brk, err);
+
 	pr_info("Personality: %x\n", personality);
 	pr_info("Command: %s\n", comm);
+	pr_info("Brk: %lx\n", mm_brk);
 err:
 	return;
 }

include/image.h

@@ -167,17 +167,24 @@ struct ckpt_arch_entry {
 	struct desc_struct		tls_array[GDT_ENTRY_TLS_ENTRIES];
 };
 
-#define CKPT_ARCH_SIZE 2048
+#define CKPT_ARCH_SIZE		2048
+#define CKPT_CORE_SIZE		8192
 
 struct core_entry {
+  union {
+    struct {
 	struct image_header		header;
 	union {
-		struct ckpt_arch_entry	arch;			/* per-arch specific */
-		u8			__pad[CKPT_ARCH_SIZE];	/* should be enough for all */
+		struct ckpt_arch_entry	arch;				/* per-arch specific */
+		u8			__arch_pad[CKPT_ARCH_SIZE];	/* should be enough for all */
 	} u;
 	u32				task_personality;
 	u8				task_comm[TASK_COMM_LEN];
 	u32				task_flags;
+	u64				mm_brk;
+    };
+    u8					__core_pad[CKPT_CORE_SIZE];
+  };
 } __packed;
 
 #endif /* CONFIG_X86_64 */

include/parasite-syscall.h

@@ -30,7 +30,7 @@ void *mmap_seized(pid_t pid, user_regs_struct_t *regs,
 int munmap_seized(pid_t pid, user_regs_struct_t *regs,
 		  void *addr, size_t length);
 int kill_seized(pid_t pid, user_regs_struct_t *where);
-
+unsigned long brk_seized(pid_t pid, unsigned long addr);
 
 int syscall_seized(pid_t pid,
 		   user_regs_struct_t *where,

include/syscall.h

@@ -109,6 +109,7 @@ static long syscall6(int nr, unsigned long arg0, unsigned long arg1,
 #define __NR_mmap		9
 #define __NR_mprotect		10
 #define __NR_munmap		11
+#define __NR_brk		12
 #define __NR_mincore		27
 #define __NR_dup		32
 #define __NR_dup2		33

kernel/binfmt-elf-for-cr-5

@@ -27,16 +27,16 @@ Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
  arch/x86/include/asm/elf.h      |    3 
  arch/x86/include/asm/elf_ckpt.h |   80 ++++++++
  arch/x86/kernel/Makefile        |    2 
- arch/x86/kernel/elf_ckpt.c      |  156 ++++++++++++++++
+ arch/x86/kernel/elf_ckpt.c      |  161 +++++++++++++++++
  arch/x86/vdso/vma.c             |   22 ++
  fs/Kconfig.binfmt               |   11 +
  fs/Makefile                     |    1 
  fs/binfmt_elf.c                 |   17 +
- fs/binfmt_elf_ckpt.c            |  381 ++++++++++++++++++++++++++++++++++++++++
+ fs/binfmt_elf_ckpt.c            |  378 ++++++++++++++++++++++++++++++++++++++++
  fs/exec.c                       |   27 +-
  include/linux/binfmts.h         |    1 
- include/linux/elf_ckpt.h        |   90 +++++++++
- 12 files changed, 779 insertions(+), 12 deletions(-)
+ include/linux/elf_ckpt.h        |   97 ++++++++++
+ 12 files changed, 788 insertions(+), 12 deletions(-)
 
 Index: linux-2.6.git/arch/x86/include/asm/elf.h
 ===================================================================
@@ -154,7 +154,7 @@ Index: linux-2.6.git/arch/x86/kernel/elf_ckpt.c
 ===================================================================
 --- /dev/null
 +++ linux-2.6.git/arch/x86/kernel/elf_ckpt.c
-@@ -0,0 +1,156 @@
+@@ -0,0 +1,161 @@
 +#include <linux/module.h>
 +#include <linux/kernel.h>
 +#include <linux/fs.h>
@@ -208,6 +208,11 @@ Index: linux-2.6.git/arch/x86/kernel/elf_ckpt.c
 +	mm_segment_t old_fs;
 +	int i, ret;
 +
++	if (core_entry->header.arch != CKPT_HEADER_ARCH_X86_64) {
++		pr_err("elf-ckpt-x86: Unsupported or corrupted header\n");
++		return -ENOEXEC;
++	}
++
 +	BUILD_BUG_ON(CKPT_GDT_ENTRY_TLS_ENTRIES != GDT_ENTRY_TLS_ENTRIES);
 +	BUILD_BUG_ON(sizeof(struct ckpt_arch_entry) > CKPT_ARCH_SIZE);
 +
@@ -424,7 +429,7 @@ Index: linux-2.6.git/fs/binfmt_elf_ckpt.c
 ===================================================================
 --- /dev/null
 +++ linux-2.6.git/fs/binfmt_elf_ckpt.c
-@@ -0,0 +1,381 @@
+@@ -0,0 +1,378 @@
 +#include <linux/module.h>
 +#include <linux/kernel.h>
 +#include <linux/fs.h>
@@ -477,8 +482,7 @@ Index: linux-2.6.git/fs/binfmt_elf_ckpt.c
 +	unsigned long map_addr;
 +
 +	unsigned long start_code, end_code, start_data, end_data;
-+	unsigned long start_brk, brk, start_stack;
-+	unsigned long elf_bss, elf_brk;
++	unsigned long start_brk, start_stack;
 +
 +#ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
 +	unsigned long vdso = -1UL;
@@ -490,15 +494,13 @@ Index: linux-2.6.git/fs/binfmt_elf_ckpt.c
 +
 +	BUILD_BUG_ON(CKPT_TASK_COMM_LEN != TASK_COMM_LEN);
 +	BUILD_BUG_ON(CKPT_PAGE_SIZE != PAGE_SIZE);
++	BUILD_BUG_ON(CKPT_CORE_SIZE != sizeof(*core_entry));
 +
 +	elf_phdr_core	= NULL;
 +	elf_phdr_pages	= NULL;
 +	nr_vma_found	= 0;
 +	nr_vma_mapped	= 0;
 +
-+	elf_bss		= 0;
-+	elf_brk		= 0;
-+
 +	start_code	= -1UL;
 +	end_code	= 0;
 +
@@ -507,7 +509,6 @@ Index: linux-2.6.git/fs/binfmt_elf_ckpt.c
 +
 +	start_stack	= -1UL;
 +	start_brk	= -1UL;
-+	brk		= -1UL;
 +
 +	fa = flex_array_alloc(sizeof(vma_entry), elf_ex->e_phnum, GFP_KERNEL);
 +	if (!fa || flex_array_prealloc(fa, 0, elf_ex->e_phnum, GFP_KERNEL)) {
@@ -589,8 +590,7 @@ Index: linux-2.6.git/fs/binfmt_elf_ckpt.c
 +		goto out;
 +	}
 +
-+	if (core_entry->header.version != CKPT_HEADER_VERSION ||
-+	    core_entry->header.arch != CKPT_HEADER_ARCH_X86_64) {
++	if (core_entry->header.version != CKPT_HEADER_VERSION) {
 +		pr_err("elf-ckpt: Unsupported or corrupted header\n");
 +		ret = -ENOEXEC;
 +		goto out;
@@ -604,7 +604,9 @@ Index: linux-2.6.git/fs/binfmt_elf_ckpt.c
 +		current->flags |= PF_RANDOMIZE;
 +
 +	/*
-+	 * FIXME: Note it flushes signal handlers as well.
++	 * FIXME: Note it flushes signal handlers as well,
++	 * so we need to dump queued signals and restore
++	 * them here.
 +	 */
 +	setup_new_exec(bprm);
 +
@@ -712,7 +714,7 @@ Index: linux-2.6.git/fs/binfmt_elf_ckpt.c
 +	current->mm->end_data		= end_data;
 +	current->mm->start_stack	= start_stack;
 +	current->mm->start_brk		= start_brk;
-+	current->mm->brk		= brk;
++	current->mm->brk		= core_entry->mm_brk;
 +
 +#ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
 +	ret = arch_setup_additional_pages_at(bprm, (void *)vdso, 0);
@@ -873,7 +875,7 @@ Index: linux-2.6.git/include/linux/elf_ckpt.h
 ===================================================================
 --- /dev/null
 +++ linux-2.6.git/include/linux/elf_ckpt.h
-@@ -0,0 +1,90 @@
+@@ -0,0 +1,97 @@
 +#ifndef _LINUX_ELF_CHECKPOINT_H
 +#define _LINUX_ELF_CHECKPOINT_H
 +
@@ -940,14 +942,21 @@ Index: linux-2.6.git/include/linux/elf_ckpt.h
 +	__u32	flags;
 +} __packed;
 +
-+#define CKPT_ARCH_SIZE 2048
++#define CKPT_ARCH_SIZE		2048
++#define CKPT_CORE_SIZE		8192
 +
 +struct core_entry {
++  union {
++    struct {
 +	struct image_header		header;
 +	__u8				arch[CKPT_ARCH_SIZE];	/* should be enough for all archs */
 +	__u32				task_personality;
 +	__u8				task_comm[CKPT_TASK_COMM_LEN];
 +	__u32				task_flags;
++	__u64				mm_brk;
++    };
++    __u8				__core_pad[CKPT_CORE_SIZE];
++  };
 +} __packed;
 +
 +#ifdef CONFIG_BINFMT_ELF_CKPT

parasite-syscall.c

@@ -100,6 +100,29 @@ int kill_seized(pid_t pid, user_regs_struct_t *where)
 	return ret;
 }
 
+unsigned long brk_seized(pid_t pid, unsigned long addr)
+{
+	user_regs_struct_t params, regs_orig;
+	unsigned long ret = -1UL;
+
+	jerr(ptrace(PTRACE_GETREGS, pid, NULL, &regs_orig), err);
+	params = regs_orig;
+
+	params.ax	= (unsigned long)__NR_brk;	/* brk		*/
+	params.di	= (unsigned long)addr;		/* @addr	*/
+
+	ret = syscall_seized(pid, &regs_orig, &params, &params);
+	if (!ret)
+		ret = (unsigned long)params.ax;
+	else
+		ret = -1UL;
+
+	if (ptrace(PTRACE_SETREGS, pid, NULL, &regs_orig))
+		pr_panic("Can't restore registers (pid: %d)\n", pid);
+err:
+	return ret;
+}
+
 int syscall_seized(pid_t pid,
 		   user_regs_struct_t *where,
 		   user_regs_struct_t *params,