Restore task's command line as well

Note binary format for core file is changed.
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>

cr-dump.c

@@ -16,6 +16,7 @@
 #include <sys/ptrace.h>
 #include <sys/user.h>
 #include <sys/wait.h>
+#include <sys/prctl.h>
 
 #include <sys/sendfile.h>
 
@@ -404,6 +405,40 @@ err:
 #define assign_reg(dst, src, e)		dst.e = (__typeof__(dst.e))src.e
 #define assign_array(dst, src, e)	memcpy(&dst.e, &src.e, sizeof(dst.e))
 
+static int get_task_comm(pid_t pid, u8 *comm)
+{
+	FILE *file = NULL;
+	char *tok1, *tok2;
+	int ret = -1;
+
+	snprintf(loc_buf, sizeof(loc_buf), "/proc/%d/stat", pid);
+	file = fopen(loc_buf, "r");
+	if (!file) {
+		pr_perror("Can't open %s", loc_buf);
+		goto err;
+	}
+
+	if (!fgets(loc_buf, sizeof(loc_buf), file)) {
+		perror("Can't read task stat");
+		goto err;
+	}
+
+	tok1 = strtok(loc_buf, "(");
+	tok2 = strtok(NULL, ")");
+	if ((long)tok1 & (long)tok2) {
+		strncpy((char *)comm, tok2, TASK_COMM_LEN);
+		ret = 0;
+	} else {
+		printf("Unable to parse task stat\n");
+		ret = -1;
+	}
+
+err:
+	if (file)
+		fclose(file);
+	return ret;
+}
+
 static int get_task_personality(pid_t pid, u32 *personality)
 {
 	FILE *file = NULL;
@@ -558,6 +593,12 @@ 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 command ... ");
+	ret = get_task_comm(pid, core->comm);
+	if (ret)
+		goto err_free;
+	pr_info("OK\n");
+
 	pr_info("Dumping header ... ");
 	core->hdr.version	= HEADER_VERSION;
 	core->hdr.arch		= HEADER_ARCH_X86_64;

cr-show.c

@@ -65,7 +65,7 @@ static void free_pstree(void)
 	INIT_LIST_HEAD(&pstree_list);
 }
 
-static void show_regs(struct cr_fdset *cr_fdset)
+static void show_core_regs(struct cr_fdset *cr_fdset)
 {
 	struct user_regs_entry regs;
 	struct desc_struct tls;
@@ -102,6 +102,28 @@ err:
 	return;
 }
 
+static void show_core_rest(struct cr_fdset *cr_fdset)
+{
+	int fd_core, i;
+	u32 personality;
+	char comm[TASK_COMM_LEN];
+
+	fd_core = cr_fdset->desc[CR_FD_CORE].fd;
+	if (fd_core < 0)
+		goto err;
+
+	lseek(fd_core, GET_FILE_OFF(struct core_entry, personality), SEEK_SET);
+	read_ptr_safe(fd_core, &personality, err);
+
+	lseek(fd_core, GET_FILE_OFF(struct core_entry, comm), SEEK_SET);
+	read_safe(fd_core, comm, TASK_COMM_LEN, err);
+
+	pr_info("Personality: %x\n", personality);
+	pr_info("Command: %s\n", comm);
+err:
+	return;
+}
+
 static void show_files(struct cr_fdset *cr_fdset)
 {
 	struct fdinfo_entry e;
@@ -188,7 +210,8 @@ static void show_core(struct cr_fdset *cr_fdset)
 	if (fd_core < 0)
 		goto out;
 
-	show_regs(cr_fdset);
+	show_core_regs(cr_fdset);
+	show_core_rest(cr_fdset);
 
 	lseek(fd_core, GET_FILE_OFF_AFTER(struct core_entry), SEEK_SET);
 

include/image.h

@@ -137,18 +137,8 @@ struct user_regs_entry {
 } __packed;
 
 struct desc_struct {
- union {
-	struct {
-		u32 a;
-		u32 b;
-	};
-	struct {
-		u16 limit0;
-		u16 base0;
-		unsigned base1: 8, type: 4, s: 1, dpl: 2, p: 1;
-		unsigned limit: 4, avl: 1, l: 1, d: 1, g: 1, base2: 8;
-	};
- };
+	u32 a;
+	u32 b;
 } __packed;
 
 struct user_fpregs_entry {
@@ -167,6 +157,7 @@ struct user_fpregs_entry {
 } __packed;
 
 #define GDT_ENTRY_TLS_ENTRIES 3
+#define TASK_COMM_LEN 16
 
 struct core_entry {
 	struct image_header		hdr;
@@ -174,6 +165,7 @@ struct core_entry {
 	struct user_fpregs_entry	fpregs;
 	struct desc_struct		tls_array[GDT_ENTRY_TLS_ENTRIES];
 	u32				personality;
+	u8				comm[TASK_COMM_LEN];
 } __packed;
 
 #endif /* CONFIG_X86_64 */

kernel/binfmt-elf-for-cr-5

@@ -18,9 +18,9 @@ Signed-off-by: Andrew Vagin <avagin@openvz.org>
 ---
  arch/x86/include/asm/elf.h |    3 
  arch/x86/vdso/vma.c        |   22 ++
- fs/binfmt_elf.c            |  402 ++++++++++++++++++++++++++++++++++++++++++++-
- include/linux/elf_ckpt.h   |  135 +++++++++++++++
- 4 files changed, 560 insertions(+), 2 deletions(-)
+ fs/binfmt_elf.c            |  405 ++++++++++++++++++++++++++++++++++++++++++++-
+ include/linux/elf_ckpt.h   |  127 ++++++++++++++
+ 4 files changed, 555 insertions(+), 2 deletions(-)
 
 Index: linux-2.6.git/arch/x86/include/asm/elf.h
 ===================================================================
@@ -88,7 +88,7 @@ Index: linux-2.6.git/fs/binfmt_elf.c
  
  static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs);
  static int load_elf_library(struct file *);
-@@ -556,6 +564,390 @@ static unsigned long randomize_stack_top
+@@ -556,6 +564,393 @@ static unsigned long randomize_stack_top
  #endif
  }
  
@@ -120,6 +120,7 @@ Index: linux-2.6.git/fs/binfmt_elf.c
 +	int cpu;
 +
 +	BUILD_BUG_ON(CKPT_GDT_ENTRY_TLS_ENTRIES != GDT_ENTRY_TLS_ENTRIES);
++	BUILD_BUG_ON(CKPT_TASK_COMM_LEN != TASK_COMM_LEN);
 +	BUILD_BUG_ON(CKPT_PAGE_SIZE != PAGE_SIZE);
 +
 +	elf_phdr_core	= NULL;
@@ -321,6 +322,8 @@ Index: linux-2.6.git/fs/binfmt_elf.c
 +		goto out_unmap;
 +	}
 +
++	set_task_comm(current, core_entry.comm);
++
 +	elf_entry	= core_entry.gpregs.ip;
 +	bprm->p		= start_stack;
 +
@@ -479,7 +482,7 @@ Index: linux-2.6.git/fs/binfmt_elf.c
  static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
  {
  	struct file *interpreter = NULL; /* to shut gcc up */
-@@ -592,7 +984,9 @@ static int load_elf_binary(struct linux_
+@@ -592,7 +987,9 @@ static int load_elf_binary(struct linux_
  	if (memcmp(loc->elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
  		goto out;
  
@@ -490,7 +493,7 @@ Index: linux-2.6.git/fs/binfmt_elf.c
  		goto out;
  	if (!elf_check_arch(&loc->elf_ex))
  		goto out;
-@@ -619,6 +1013,12 @@ static int load_elf_binary(struct linux_
+@@ -619,6 +1016,12 @@ static int load_elf_binary(struct linux_
  		goto out_free_ph;
  	}
  
@@ -507,7 +510,7 @@ Index: linux-2.6.git/include/linux/elf_ckpt.h
 ===================================================================
 --- /dev/null
 +++ linux-2.6.git/include/linux/elf_ckpt.h
-@@ -0,0 +1,135 @@
+@@ -0,0 +1,127 @@
 +#ifndef _LINUX_ELF_CHECKPOINT_H
 +#define _LINUX_ELF_CHECKPOINT_H
 +
@@ -531,6 +534,7 @@ Index: linux-2.6.git/include/linux/elf_ckpt.h
 +#define PT_CKPT_PAGES			(PT_LOOS + PT_CKPT_OFFSET + 3)
 +
 +#define CKPT_PAGE_SIZE			4096
++#define CKPT_TASK_COMM_LEN		16
 +#define CKPT_GDT_ENTRY_TLS_ENTRIES	3
 +
 +#define HEADER_VERSION			1
@@ -604,18 +608,8 @@ Index: linux-2.6.git/include/linux/elf_ckpt.h
 +} __packed;
 +
 +struct desc_struct_entry {
-+ union {
-+	struct {
-+		__u32 a;
-+		__u32 b;
-+	};
-+	struct {
-+		__u16 limit0;
-+		__u16 base0;
-+		unsigned base1: 8, type: 4, s: 1, dpl: 2, p: 1;
-+		unsigned limit: 4, avl: 1, l: 1, d: 1, g: 1, base2: 8;
-+	};
-+ };
++	__u32	a;
++	__u32	b;
 +} __packed;
 +
 +struct user_fpregs_entry {
@@ -638,6 +632,7 @@ Index: linux-2.6.git/include/linux/elf_ckpt.h
 +	struct user_fpregs_entry	fpregs;
 +	struct desc_struct		tls_array[CKPT_GDT_ENTRY_TLS_ENTRIES];
 +	__u32				personality;
++	__u8				comm[CKPT_TASK_COMM_LEN];
 +} __packed;
 +
 +#endif /* __KERNEL__ */