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Subject[PATCH 1/1] x86: Add process memory layout to coredump file
From
This patch just add memory layout(same as /proc/pid/maps) to
coredump file. The layout is appended to corenote segment with
flag NT_MAPS=7.

Signed-off-by: cheney <cdmalord@gmail.com>
---
fs/binfmt_elf.c | 210 ++++++++++++++++++++++++++++++++++++++++++++++++++-
include/linux/elf.h | 1 +
2 files changed, 208 insertions(+), 3 deletions(-)

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 21ac5ee..d9d07f4 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -35,6 +35,7 @@
#include <asm/uaccess.h>
#include <asm/param.h>
#include <asm/page.h>
+#include <linux/seq_file.h>

static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs);
static int load_elf_library(struct file *);
@@ -1200,6 +1201,12 @@ static int notesize(struct memelfnote *en)
#define DUMP_WRITE(addr, nr, foffset) \
do { if (!dump_write(file, (addr), (nr))) return 0; *foffset +=
(nr); } while(0)

+static struct vm_area_struct *first_vma(struct task_struct *tsk,
+ struct vm_area_struct *gate_vma);
+static struct vm_area_struct *next_vma(struct vm_area_struct *this_vma,
+ struct vm_area_struct *gate_vma);
+/*extern char *mangle_path(char *s, char *p, char *esc);
+*/
static int alignfile(struct file *file, loff_t *foffset)
{
static const char buf[4] = { 0, };
@@ -1207,6 +1214,156 @@ static int alignfile(struct file *file, loff_t *foffset)
return 1;
}

+static int pad_spaces(char *p, int len)
+{
+ int i;
+ len = 25 + sizeof(void *) * 6 - len;
+ if (len < 1)
+ len = 1;
+ i = len;
+ while (i--)
+ *p++ = ' ';
+ return len;
+}
+
+const char *get_vma_name(struct vm_area_struct *vma)
+{
+ const char *name = arch_vma_name(vma);
+ if (!name) {
+ struct mm_struct *mm = vma->vm_mm;
+ if (mm) {
+ if (vma->vm_start <= mm->brk &&
+ vma->vm_end >= mm->start_brk) {
+ name = "[heap]";
+ } else if (vma->vm_start <= mm->start_stack &&
+ vma->vm_end >= mm->start_stack) {
+ name = "[stack]";
+ }
+ } else {
+ name = "[vdso]";
+ }
+ }
+ return name;
+}
+
+/* handle memory map in core
+ * if filp=0 it just calculate the size of maps.
+ */
+static int core_handle_maps(struct file *file, struct memelfnote *notes,
+ loff_t *foffset)
+{
+ size_t maps_size = 0;
+ size_t len;
+ size_t space;
+ struct vm_area_struct *vma, *gate_vma;
+ int flags;
+ struct inode *inode;
+ unsigned long ino;
+ unsigned long long pgoff;
+ unsigned long start, end;
+ dev_t dev;
+ char *esc = "\n";
+ char *p;
+ char *s;
+ char *buf = notes->data;
+ size_t core_limit = notes->datasz;
+ gate_vma = get_gate_vma(current->mm);
+
+ for (vma = first_vma(current, gate_vma); vma != NULL;
+ vma = next_vma(vma, gate_vma)) {
+ flags = vma->vm_flags;
+ ino = 0;
+ dev = 0;
+ space = 0;
+ inode = NULL;
+ pgoff = 0;
+ len = 0;
+ if (vma->vm_file) {
+ inode = vma->vm_file->f_dentry->d_inode;
+ dev = inode->i_sb->s_dev;
+ ino = inode->i_ino;
+ pgoff = ((loff_t)vma->vm_pgoff) << PAGE_SHIFT;
+ }
+ start = vma->vm_start;
+ if (stack_guard_page_start(vma, start))
+ start += PAGE_SIZE;
+ end = vma->vm_end;
+ if (stack_guard_page_end(vma, end))
+ end -= PAGE_SIZE;
+ len = sprintf(buf, "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu",
+ start,
+ end,
+ flags & VM_READ ? 'r' : '-',
+ flags & VM_WRITE ? 'w' : '-',
+ flags & VM_EXEC ? 'x' : '-',
+ flags & VM_MAYSHARE ? 's' : 'p',
+ pgoff,
+ MAJOR(dev), MINOR(dev), ino);
+ maps_size += len;
+ if (file) {
+ if (maps_size > core_limit)
+ break;
+ DUMP_WRITE(buf, len, foffset);
+ }
+ if (vma->vm_file) {
+ space = pad_spaces(buf, len);
+ s = buf + space;
+ p = d_path(&vma->vm_file->f_path, s, maps_size-1);
+ if (!IS_ERR(p)) {
+ char *last;
+ last = mangle_path(s, p, esc);
+ len = last - buf;
+ maps_size += len;
+ if (file) {
+ if (maps_size > core_limit)
+ break;
+ DUMP_WRITE(buf, len, foffset);
+ }
+ }
+ } else {
+ const char *name = get_vma_name(vma);
+ if (name) {
+ space = pad_spaces(buf, len);
+ maps_size += space;
+ maps_size += strlen(name);
+ if (file) {
+ if (maps_size > core_limit)
+ break;
+ DUMP_WRITE(buf, space, foffset);
+ DUMP_WRITE(name, strlen(name), foffset);
+ }
+ }
+ }
+ maps_size++;
+ if (file) {
+ if (maps_size > core_limit)
+ break;
+ DUMP_WRITE("\n", 1, foffset);
+ }
+ }
+ return maps_size;
+}
+
+static int writemaps(struct file *file, struct memelfnote *men,
+ loff_t *foffset)
+{
+ struct elf_note en;
+ en.n_namesz = strlen(men->name) + 1;
+ en.n_descsz = men->datasz;
+ en.n_type = men->type;
+
+ DUMP_WRITE(&en, sizeof(en), foffset);
+ DUMP_WRITE(men->name, en.n_namesz, foffset);
+ if (!alignfile(file, foffset))
+ return 0;
+ if (!core_handle_maps(file, men, foffset))
+ return 0;
+ if (!alignfile(file, foffset))
+ return 0;
+
+ return 1;
+}
+
static int writenote(struct memelfnote *men, struct file *file,
loff_t *foffset)
{
@@ -1374,6 +1531,8 @@ struct elf_note_info {
struct elf_thread_core_info *thread;
struct memelfnote psinfo;
struct memelfnote auxv;
+ /* maps is for memory layout */
+ struct memelfnote maps;
size_t size;
int thread_notes;
};
@@ -1460,6 +1619,7 @@ static int fill_note_info(struct elfhdr *elf, int phdrs,
struct elf_prpsinfo *psinfo;
struct core_thread *ct;
unsigned int i;
+ int maps_size;

info->size = 0;
info->thread = NULL;
@@ -1468,6 +1628,21 @@ static int fill_note_info(struct elfhdr *elf, int phdrs,
if (psinfo == NULL)
return 0;

+ info->maps.data = kmalloc(PAGE_SIZE, GFP_KERNEL);
+ if (info->maps.data == NULL) {
+ kfree(psinfo);
+ return 0;
+ }
+ /* Just calculate maps' size */
+ maps_size = core_handle_maps(NULL, &info->maps, NULL);
+ if (!maps_size) {
+ kfree(psinfo);
+ kfree(info->maps.data);
+ return 0;
+ }
+ fill_note(&info->maps, "CORE", NT_MAPS, maps_size, info->maps.data);
+ info->size += notesize(&info->maps);
+
fill_note(&info->psinfo, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);

/*
@@ -1572,6 +1747,10 @@ static int write_note_info(struct elf_note_info *info,
t = t->next;
} while (t);

+ /* Write maps */
+ if (!writemaps(file, &info->maps, foffset))
+ return 0;
+
return 1;
}

@@ -1588,6 +1767,7 @@ static void free_note_info(struct elf_note_info *info)
kfree(t);
}
kfree(info->psinfo.data);
+ kfree(info->maps.data);
}

#else
@@ -1648,6 +1828,7 @@ struct elf_note_info {
struct memelfnote *notes;
struct elf_prstatus *prstatus; /* NT_PRSTATUS */
struct elf_prpsinfo *psinfo; /* NT_PRPSINFO */
+ char *maps; /* NT_MAPS */
struct list_head thread_list;
elf_fpregset_t *fpu;
#ifdef ELF_CORE_COPY_XFPREGS
@@ -1663,12 +1844,16 @@ static int elf_note_info_init(struct
elf_note_info *info)
INIT_LIST_HEAD(&info->thread_list);

/* Allocate space for six ELF notes */
- info->notes = kmalloc(6 * sizeof(struct memelfnote), GFP_KERNEL);
+ /* Add maps into notes */
+ info->notes = kmalloc((6+1) * sizeof(struct memelfnote), GFP_KERNEL);
if (!info->notes)
return 0;
+ info->maps = kmalloc(PAGE_SIZE, GFP_KERNEL);
+ if (!info->maps)
+ goto notes_free;
info->psinfo = kmalloc(sizeof(*info->psinfo), GFP_KERNEL);
if (!info->psinfo)
- goto notes_free;
+ goto maps_free;
info->prstatus = kmalloc(sizeof(*info->prstatus), GFP_KERNEL);
if (!info->prstatus)
goto psinfo_free;
@@ -1689,6 +1874,8 @@ static int elf_note_info_init(struct elf_note_info *info)
kfree(info->prstatus);
psinfo_free:
kfree(info->psinfo);
+ maps_free:
+ kfree(info->maps);
notes_free:
kfree(info->notes);
return 0;
@@ -1699,6 +1886,7 @@ static int fill_note_info(struct elfhdr *elf, int phdrs,
long signr, struct pt_regs *regs)
{
struct list_head *t;
+ int maps_size;

if (!elf_note_info_init(info))
return 0;
@@ -1761,6 +1949,14 @@ static int fill_note_info(struct elfhdr *elf, int phdrs,
sizeof(*info->xfpu), info->xfpu);
#endif

+ info->notes[info->numnote].data = info->maps;
+ /* Just calculate maps's size */
+ maps_size = core_handle_maps(NULL, info->notes + info->numnote, NULL);
+ if (!maps_size)
+ return 0;
+ fill_note(info->notes + info->numnote++, "CORE", NT_MAPS,
+ maps_size, info->maps);
+
return 1;
}

@@ -1783,9 +1979,16 @@ static int write_note_info(struct elf_note_info *info,
int i;
struct list_head *t;

- for (i = 0; i < info->numnote; i++)
+ for (i = 0; i < info->numnote; i++) {
+ /* Write maps */
+ if (info->notes[i].type == NT_MAPS) {
+ if (!writemaps(file, info->notes + i, foffset))
+ return 0;
+ continue;
+ }
if (!writenote(info->notes + i, file, foffset))
return 0;
+ }

/* write out the thread status notes section */
list_for_each(t, &info->thread_list) {
@@ -1812,6 +2015,7 @@ static void free_note_info(struct elf_note_info *info)
kfree(info->psinfo);
kfree(info->notes);
kfree(info->fpu);
+ kfree(info->maps);
#ifdef ELF_CORE_COPY_XFPREGS
kfree(info->xfpu);
#endif
diff --git a/include/linux/elf.h b/include/linux/elf.h
index 31f0508..b9d710b 100644
--- a/include/linux/elf.h
+++ b/include/linux/elf.h
@@ -381,6 +381,7 @@ typedef struct elf64_shdr {
#define NT_PRPSINFO 3
#define NT_TASKSTRUCT 4
#define NT_AUXV 6
+#define NT_MAPS 7
#define NT_PRXFPREG 0x46e62b7f /* copied from
gdb5.1/include/elf/common.h */
#define NT_PPC_VMX 0x100 /* PowerPC Altivec/VMX registers */
#define NT_PPC_SPE 0x101 /* PowerPC SPE/EVR registers */
--
1.5.3.4

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