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Subject[Patch 2/21] Create elfcore-common.c for ELF class independent core generation helpers
Move the common code, shared by both native and compat ELF core generation code
to a single instance.These functions could be re-used later for application
core dump infrastructure.

Signed-off-by: Suzuki K. Poulose <suzuki@in.ibm.com>
---
fs/Makefile | 1
fs/binfmt_elf.c | 129 ---------------------------------------
fs/elfcore-common.c | 126 ++++++++++++++++++++++++++++++++++++++
include/linux/elfcore-internal.h | 35 ++++++++++
4 files changed, 163 insertions(+), 128 deletions(-)

Index: linux-2.6.36-rc7/fs/binfmt_elf.c
===================================================================
--- linux-2.6.36-rc7.orig/fs/binfmt_elf.c
+++ linux-2.6.36-rc7/fs/binfmt_elf.c
@@ -46,6 +46,7 @@ static unsigned long elf_map(struct file
* don't even try.
*/
#ifdef CONFIG_ELF_CORE
+#include <linux/elfcore-internal.h>
static int elf_core_dump(struct coredump_params *cprm);
#else
#define elf_core_dump NULL
@@ -1087,98 +1088,6 @@ out:
* Jeremy Fitzhardinge <jeremy@sw.oz.au>
*/

-/*
- * Decide what to dump of a segment, part, all or none.
- */
-static unsigned long vma_dump_size(struct vm_area_struct *vma,
- unsigned long mm_flags)
-{
-#define FILTER(type) (mm_flags & (1UL << MMF_DUMP_##type))
-
- /* The vma can be set up to tell us the answer directly. */
- if (vma->vm_flags & VM_ALWAYSDUMP)
- goto whole;
-
- /* Hugetlb memory check */
- if (vma->vm_flags & VM_HUGETLB) {
- if ((vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_SHARED))
- goto whole;
- if (!(vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_PRIVATE))
- goto whole;
- }
-
- /* Do not dump I/O mapped devices or special mappings */
- if (vma->vm_flags & (VM_IO | VM_RESERVED))
- return 0;
-
- /* By default, dump shared memory if mapped from an anonymous file. */
- if (vma->vm_flags & VM_SHARED) {
- if (vma->vm_file->f_path.dentry->d_inode->i_nlink == 0 ?
- FILTER(ANON_SHARED) : FILTER(MAPPED_SHARED))
- goto whole;
- return 0;
- }
-
- /* Dump segments that have been written to. */
- if (vma->anon_vma && FILTER(ANON_PRIVATE))
- goto whole;
- if (vma->vm_file == NULL)
- return 0;
-
- if (FILTER(MAPPED_PRIVATE))
- goto whole;
-
- /*
- * If this looks like the beginning of a DSO or executable mapping,
- * check for an ELF header. If we find one, dump the first page to
- * aid in determining what was mapped here.
- */
- if (FILTER(ELF_HEADERS) &&
- vma->vm_pgoff == 0 && (vma->vm_flags & VM_READ)) {
- u32 __user *header = (u32 __user *) vma->vm_start;
- u32 word;
- mm_segment_t fs = get_fs();
- /*
- * Doing it this way gets the constant folded by GCC.
- */
- union {
- u32 cmp;
- char elfmag[SELFMAG];
- } magic;
- BUILD_BUG_ON(SELFMAG != sizeof word);
- magic.elfmag[EI_MAG0] = ELFMAG0;
- magic.elfmag[EI_MAG1] = ELFMAG1;
- magic.elfmag[EI_MAG2] = ELFMAG2;
- magic.elfmag[EI_MAG3] = ELFMAG3;
- /*
- * Switch to the user "segment" for get_user(),
- * then put back what elf_core_dump() had in place.
- */
- set_fs(USER_DS);
- if (unlikely(get_user(word, header)))
- word = 0;
- set_fs(fs);
- if (word == magic.cmp)
- return PAGE_SIZE;
- }
-
-#undef FILTER
-
- return 0;
-
-whole:
- return vma->vm_end - vma->vm_start;
-}
-
-/* An ELF note in memory */
-struct memelfnote
-{
- const char *name;
- int type;
- unsigned int datasz;
- void *data;
-};
-
static int notesize(struct memelfnote *en)
{
int sz;
@@ -1256,16 +1165,6 @@ static void fill_elf_note_phdr(struct el
return;
}

-static void fill_note(struct memelfnote *note, const char *name, int type,
- unsigned int sz, void *data)
-{
- note->name = name;
- note->type = type;
- note->datasz = sz;
- note->data = data;
- return;
-}
-
/*
* fill up all the fields in prstatus from the given task struct, except
* registers which need to be filled up separately.
@@ -1812,32 +1711,6 @@ static void free_note_info(struct elf_no

#endif

-static struct vm_area_struct *first_vma(struct task_struct *tsk,
- struct vm_area_struct *gate_vma)
-{
- struct vm_area_struct *ret = tsk->mm->mmap;
-
- if (ret)
- return ret;
- return gate_vma;
-}
-/*
- * Helper function for iterating across a vma list. It ensures that the caller
- * will visit `gate_vma' prior to terminating the search.
- */
-static struct vm_area_struct *next_vma(struct vm_area_struct *this_vma,
- struct vm_area_struct *gate_vma)
-{
- struct vm_area_struct *ret;
-
- ret = this_vma->vm_next;
- if (ret)
- return ret;
- if (this_vma == gate_vma)
- return NULL;
- return gate_vma;
-}
-
static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum,
elf_addr_t e_shoff, int segs)
{
Index: linux-2.6.36-rc7/fs/elfcore-common.c
===================================================================
--- /dev/null
+++ linux-2.6.36-rc7/fs/elfcore-common.c
@@ -0,0 +1,131 @@
+/*
+ * Copyright 1993, 1994: Eric Youngdale (ericy@cais.com).
+ *
+ * Initial write up for ELF_CORE :
+ * Modelled on fs/exec.c:aout_core_dump()
+ * Jeremy Fitzhardinge <jeremy@sw.oz.au>
+ *
+ * Moved common routines used by both native and compat ELF core generation
+ * from binfmt_elf.c to a single instance.
+ * Suzuki K. Poulose <suzuki@in.ibm.com>
+ */
+
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/sched.h>
+#include <linux/fs.h>
+#include <linux/elf.h>
+#include <asm/uaccess.h>
+#include <asm/param.h>
+#include <asm/page.h>
+
+#include <linux/elfcore-internal.h>
+
+struct vm_area_struct *first_vma(struct task_struct *tsk,
+ struct vm_area_struct *gate_vma)
+{
+ struct vm_area_struct *ret = tsk->mm->mmap;
+
+ if (ret)
+ return ret;
+ return gate_vma;
+}
+/*
+ * Helper function for iterating across a vma list. It ensures that the caller
+ * will visit `gate_vma' prior to terminating the search.
+ */
+struct vm_area_struct *next_vma(struct vm_area_struct *this_vma,
+ struct vm_area_struct *gate_vma)
+{
+ struct vm_area_struct *ret;
+
+ ret = this_vma->vm_next;
+ if (ret)
+ return ret;
+ if (this_vma == gate_vma)
+ return NULL;
+ return gate_vma;
+}
+
+/*
+ * Decide what to dump of a segment, part, all or none.
+ */
+unsigned long vma_dump_size(struct vm_area_struct *vma,
+ unsigned long mm_flags)
+{
+#define FILTER(type) (mm_flags & (1UL << MMF_DUMP_##type))
+
+ /* The vma can be set up to tell us the answer directly. */
+ if (vma->vm_flags & VM_ALWAYSDUMP)
+ goto whole;
+
+ /* Hugetlb memory check */
+ if (vma->vm_flags & VM_HUGETLB) {
+ if ((vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_SHARED))
+ goto whole;
+ if (!(vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_PRIVATE))
+ goto whole;
+ }
+
+ /* Do not dump I/O mapped devices or special mappings */
+ if (vma->vm_flags & (VM_IO | VM_RESERVED))
+ return 0;
+
+ /* By default, dump shared memory if mapped from an anonymous file. */
+ if (vma->vm_flags & VM_SHARED) {
+ if (vma->vm_file->f_path.dentry->d_inode->i_nlink == 0 ?
+ FILTER(ANON_SHARED) : FILTER(MAPPED_SHARED))
+ goto whole;
+ return 0;
+ }
+
+ /* Dump segments that have been written to. */
+ if (vma->anon_vma && FILTER(ANON_PRIVATE))
+ goto whole;
+ if (vma->vm_file == NULL)
+ return 0;
+
+ if (FILTER(MAPPED_PRIVATE))
+ goto whole;
+
+ /*
+ * If this looks like the beginning of a DSO or executable mapping,
+ * check for an ELF header. If we find one, dump the first page to
+ * aid in determining what was mapped here.
+ */
+ if (FILTER(ELF_HEADERS) &&
+ vma->vm_pgoff == 0 && (vma->vm_flags & VM_READ)) {
+ u32 __user *header = (u32 __user *) vma->vm_start;
+ u32 word;
+ mm_segment_t fs = get_fs();
+ /*
+ * Doing it this way gets the constant folded by GCC.
+ */
+ union {
+ u32 cmp;
+ char elfmag[SELFMAG];
+ } magic;
+ BUILD_BUG_ON(SELFMAG != sizeof word);
+ magic.elfmag[EI_MAG0] = ELFMAG0;
+ magic.elfmag[EI_MAG1] = ELFMAG1;
+ magic.elfmag[EI_MAG2] = ELFMAG2;
+ magic.elfmag[EI_MAG3] = ELFMAG3;
+ /*
+ * Switch to the user "segment" for get_user(),
+ * then put back what elf_core_dump() had in place.
+ */
+ set_fs(USER_DS);
+ if (unlikely(get_user(word, header)))
+ word = 0;
+ set_fs(fs);
+ if (word == magic.cmp)
+ return PAGE_SIZE;
+ }
+
+#undef FILTER
+
+ return 0;
+
+whole:
+ return vma->vm_end - vma->vm_start;
+}
Index: linux-2.6.36-rc7/include/linux/elfcore-internal.h
===================================================================
--- /dev/null
+++ linux-2.6.36-rc7/include/linux/elfcore-internal.h
@@ -0,0 +1,44 @@
+/*
+ * Common routines for native and compat elf core generation.
+ *
+ * Copyright 1993, 1994: Eric Youngdale (ericy@cais.com).
+ *
+ * Modelled on fs/exec.c:aout_core_dump()
+ * Jeremy Fitzhardinge <jeremy@sw.oz.au>
+ *
+ * Moved the common routines from binfmt_elf.c to elfcore-common.c
+ * - Suzuki K. Poulose <suzuki@in.ibm.com>
+ */
+
+#ifndef __ELF_CORE_INTERNAL_H
+#define __ELF_CORE_INTERNAL_H
+
+#ifdef __KERNEL__
+
+/* An ELF note in memory */
+struct memelfnote
+{
+ const char *name;
+ int type;
+ unsigned int datasz;
+ void *data;
+};
+
+static inline void fill_note(struct memelfnote *note, const char *name,
+ int type, unsigned int sz, void *data)
+{
+ note->name = name;
+ note->type = type;
+ note->datasz = sz;
+ note->data = data;
+}
+
+extern struct vm_area_struct *first_vma(struct task_struct *tsk,
+ struct vm_area_struct *gate_vma);
+extern struct vm_area_struct *next_vma(struct vm_area_struct *this_vma,
+ struct vm_area_struct *gate_vma);
+extern unsigned long vma_dump_size(struct vm_area_struct *vma,
+ unsigned long mm_flags);
+
+#endif
+#endif
Index: linux-2.6.36-rc7/fs/Makefile
===================================================================
--- linux-2.6.36-rc7.orig/fs/Makefile
+++ linux-2.6.36-rc7/fs/Makefile
@@ -42,6 +42,7 @@ obj-y += binfmt_script.o

obj-$(CONFIG_BINFMT_ELF) += binfmt_elf.o
obj-$(CONFIG_COMPAT_BINFMT_ELF) += compat_binfmt_elf.o
+obj-$(CONFIG_ELF_CORE) += elfcore-common.o
obj-$(CONFIG_BINFMT_ELF_FDPIC) += binfmt_elf_fdpic.o
obj-$(CONFIG_BINFMT_SOM) += binfmt_som.o
obj-$(CONFIG_BINFMT_FLAT) += binfmt_flat.o

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