[Patch 19/21] Identify the ELF class of the process

["Suzuki K. Poulose" <suzuki@in.ibm.com>]

Identify the ELF class of the process to native or compat.

Signed-off-by: Suzuki K. Poulose <suzuki@in.ibm.com>
---
 fs/proc/gencore.c |   17 +++++++++++++----
 fs/proc/gencore.h |    3 +++
 2 files changed, 16 insertions(+), 4 deletions(-)

Index: linux-2.6.36-rc7/fs/proc/gencore.c
===================================================================
--- linux-2.6.36-rc7.orig/fs/proc/gencore.c
+++ linux-2.6.36-rc7/fs/proc/gencore.c
@@ -106,7 +106,8 @@ static ssize_t read_gencore(struct file 
 	}
 	mutex_unlock(&core_mutex);
 
-	ret = elf_read_gencore(cp, buffer, buflen, fpos);
+	if (cp->elf_class == ELF_CLASS_NATIVE)
+		ret = elf_read_gencore(cp, buffer, buflen, fpos);
 
 out:
 	put_task_struct(task);
@@ -177,8 +178,8 @@ static int release_gencore(struct inode 
 /*
  * Determine whether the task is an ELF executable.
  * Returns
- * 	< 0	- Non-ELF
- * 	0 	- Native ELF Executable
+ * 	-EINVAL - On non ELF execs
+ * 	Returns the ELF_CLASS_NATIVE or ELF_CLASS_COMPAT
  */
 static int get_elf_class(struct task_struct *task)
 {
@@ -193,8 +194,15 @@ static int get_elf_class(struct task_str
 	if (memcmp(hdr.e_ident, ELFMAG, SELFMAG))
 		return -EINVAL;
 	if (elf_check_arch(&hdr))
-		return 0;
+		return ELF_CLASS_NATIVE;
 
+#ifdef CONFIG_COMPAT_BINFMT_ELF
+	{
+		struct elf32_hdr *chdr = (struct elf32_hdr *)&hdr;
+		if (compat_elf_check_arch(chdr))
+			return ELF_CLASS_COMPAT;
+	}
+#endif
 	return -EINVAL;
 }
 
@@ -238,6 +246,7 @@ static int open_gencore(struct inode *in
 	INIT_LIST_HEAD(&cp->list);
 	list_add(&cp->list, &core_list);
 	mutex_unlock(&core_mutex);
+	cp->elf_class = elf_class;
 
 	max_regset = get_max_regsets(task);
 
Index: linux-2.6.36-rc7/fs/proc/gencore.h
===================================================================
--- linux-2.6.36-rc7.orig/fs/proc/gencore.h
+++ linux-2.6.36-rc7/fs/proc/gencore.h
@@ -6,6 +6,8 @@
 #include <linux/elfcore.h>
 #include <linux/elfcore-internal.h>
 
+enum { ELF_CLASS_NATIVE, ELF_CLASS_COMPAT };
+
 struct elf_thread_core_info {
 	unsigned short frozen;
 	unsigned short num_notes;	/* Number of notes for this thread */
@@ -28,6 +30,7 @@ struct core_proc {
 	size_t nphdrs;		/* number of phdrs */
 	size_t notes_size;
 	size_t size;
+	unsigned char elf_class;
 };
 
 extern void try_to_freeze_core_threads(struct core_proc *cp);