elf coredump: replace ELF_CORE_EXTRA_* macros by functions

elf_core_dump() and elf_fdpic_core_dump() use #ifdef and the corresponding
macro for hiding _multiline_ logics in functions. This patch removes
#ifdef and replaces ELF_CORE_EXTRA_* by corresponding functions. For
architectures not implemeonting ELF_CORE_EXTRA_*, we use weak functions in
order to reduce a range of modification.

This cleanup is for my next patches, but I think this cleanup itself is
worth doing regardless of my firnal purpose.

Signed-off-by: Daisuke HATAYAMA <[e-mail]>
Cc: "Luck, Tony" <[e-mail]>
Cc: Jeff Dike <[e-mail]>
Cc: David Howells <[e-mail]>
Cc: Greg Ungerer <[e-mail]>
Cc: Roland McGrath <[e-mail]>
Cc: Oleg Nesterov <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Alexander Viro <[e-mail]>
Cc: Andi Kleen <[e-mail]>
Cc: Alan Cox <[e-mail]>
Cc: <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

arch/ia64/include/asm/elf.h

···
 	NEW_AUX_ENT(AT_SYSINFO_EHDR, (unsigned long) GATE_EHDR);		\
 } while (0)
 
-
-/*
- * These macros parameterize elf_core_dump in fs/binfmt_elf.c to write out
- * extra segments containing the gate DSO contents.  Dumping its
- * contents makes post-mortem fully interpretable later without matching up
- * the same kernel and hardware config to see what PC values meant.
- * Dumping its extra ELF program headers includes all the other information
- * a debugger needs to easily find how the gate DSO was being used.
- */
-#define ELF_CORE_EXTRA_PHDRS		(GATE_EHDR->e_phnum)
-#define ELF_CORE_WRITE_EXTRA_PHDRS						\
-do {										\
-	const struct elf_phdr *const gate_phdrs =			      \
-		(const struct elf_phdr *) (GATE_ADDR + GATE_EHDR->e_phoff);   \
-	int i;									\
-	Elf64_Off ofs = 0;						      \
-	for (i = 0; i < GATE_EHDR->e_phnum; ++i) {				\
-		struct elf_phdr phdr = gate_phdrs[i];			      \
-		if (phdr.p_type == PT_LOAD) {					\
-			phdr.p_memsz = PAGE_ALIGN(phdr.p_memsz);	      \
-			phdr.p_filesz = phdr.p_memsz;			      \
-			if (ofs == 0) {					      \
-				ofs = phdr.p_offset = offset;		      \
-			offset += phdr.p_filesz;				\
-		}							      \
-		else							      \
-				phdr.p_offset = ofs;			      \
-		}							      \
-		else							      \
-			phdr.p_offset += ofs;					\
-		phdr.p_paddr = 0; /* match other core phdrs */			\
-		DUMP_WRITE(&phdr, sizeof(phdr));				\
-	}									\
-} while (0)
-#define ELF_CORE_WRITE_EXTRA_DATA					\
-do {									\
-	const struct elf_phdr *const gate_phdrs =			      \
-		(const struct elf_phdr *) (GATE_ADDR + GATE_EHDR->e_phoff);   \
-	int i;								\
-	for (i = 0; i < GATE_EHDR->e_phnum; ++i) {			\
-		if (gate_phdrs[i].p_type == PT_LOAD) {			      \
-			DUMP_WRITE((void *) gate_phdrs[i].p_vaddr,	      \
-				   PAGE_ALIGN(gate_phdrs[i].p_memsz));	      \
-			break;						      \
-		}							      \
-	}								\
-} while (0)
-
 /*
  * format for entries in the Global Offset Table
  */

arch/ia64/kernel/Makefile

···
 obj-$(CONFIG_DMAR)		+= pci-dma.o
 obj-$(CONFIG_SWIOTLB)		+= pci-swiotlb.o
 
+obj-$(CONFIG_BINFMT_ELF)	+= elfcore.o
+
 # fp_emulate() expects f2-f5,f16-f31 to contain the user-level state.
 CFLAGS_traps.o  += -mfixed-range=f2-f5,f16-f31
 

arch/ia64/kernel/elfcore.c

···
+#include <linux/elf.h>
+#include <linux/coredump.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+
+#include <asm/elf.h>
+
+
+Elf64_Half elf_core_extra_phdrs(void)
+{
+	return GATE_EHDR->e_phnum;
+}
+
+int elf_core_write_extra_phdrs(struct file *file, loff_t offset, size_t *size,
+			       unsigned long limit)
+{
+	const struct elf_phdr *const gate_phdrs =
+		(const struct elf_phdr *) (GATE_ADDR + GATE_EHDR->e_phoff);
+	int i;
+	Elf64_Off ofs = 0;
+
+	for (i = 0; i < GATE_EHDR->e_phnum; ++i) {
+		struct elf_phdr phdr = gate_phdrs[i];
+
+		if (phdr.p_type == PT_LOAD) {
+			phdr.p_memsz = PAGE_ALIGN(phdr.p_memsz);
+			phdr.p_filesz = phdr.p_memsz;
+			if (ofs == 0) {
+				ofs = phdr.p_offset = offset;
+				offset += phdr.p_filesz;
+			} else {
+				phdr.p_offset = ofs;
+			}
+		} else {
+			phdr.p_offset += ofs;
+		}
+		phdr.p_paddr = 0; /* match other core phdrs */
+		*size += sizeof(phdr);
+		if (*size > limit || !dump_write(file, &phdr, sizeof(phdr)))
+			return 0;
+	}
+	return 1;
+}
+
+int elf_core_write_extra_data(struct file *file, size_t *size,
+			      unsigned long limit)
+{
+	const struct elf_phdr *const gate_phdrs =
+		(const struct elf_phdr *) (GATE_ADDR + GATE_EHDR->e_phoff);
+	int i;
+
+	for (i = 0; i < GATE_EHDR->e_phnum; ++i) {
+		if (gate_phdrs[i].p_type == PT_LOAD) {
+			void *addr = (void *)gate_phdrs[i].p_vaddr;
+			size_t memsz = PAGE_ALIGN(gate_phdrs[i].p_memsz);
+
+			*size += memsz;
+			if (*size > limit || !dump_write(file, addr, memsz))
+				return 0;
+			break;
+		}
+	}
+	return 1;
+}

arch/um/sys-i386/Makefile

···
 	ptrace_user.o setjmp.o signal.o stub.o stub_segv.o syscalls.o sysrq.o \
 	sys_call_table.o tls.o
 
+obj-$(CONFIG_BINFMT_ELF) += elfcore.o
+
 subarch-obj-y = lib/semaphore_32.o lib/string_32.o
 subarch-obj-$(CONFIG_HIGHMEM) += mm/highmem_32.o
 subarch-obj-$(CONFIG_MODULES) += kernel/module.o

arch/um/sys-i386/asm/elf.h

···
 	}							\
 } while (0)
 
-/*
- * These macros parameterize elf_core_dump in fs/binfmt_elf.c to write out
- * extra segments containing the vsyscall DSO contents.  Dumping its
- * contents makes post-mortem fully interpretable later without matching up
- * the same kernel and hardware config to see what PC values meant.
- * Dumping its extra ELF program headers includes all the other information
- * a debugger needs to easily find how the vsyscall DSO was being used.
- */
-#define ELF_CORE_EXTRA_PHDRS						      \
-	(vsyscall_ehdr ? (((struct elfhdr *)vsyscall_ehdr)->e_phnum) : 0 )
-
-#define ELF_CORE_WRITE_EXTRA_PHDRS					      \
-if ( vsyscall_ehdr ) {							      \
-	const struct elfhdr *const ehdrp = (struct elfhdr *)vsyscall_ehdr;    \
-	const struct elf_phdr *const phdrp =				      \
-		(const struct elf_phdr *) (vsyscall_ehdr + ehdrp->e_phoff);   \
-	int i;								      \
-	Elf32_Off ofs = 0;						      \
-	for (i = 0; i < ehdrp->e_phnum; ++i) {				      \
-		struct elf_phdr phdr = phdrp[i];			      \
-		if (phdr.p_type == PT_LOAD) {				      \
-			ofs = phdr.p_offset = offset;			      \
-			offset += phdr.p_filesz;			      \
-		}							      \
-		else							      \
-			phdr.p_offset += ofs;				      \
-		phdr.p_paddr = 0; /* match other core phdrs */		      \
-		DUMP_WRITE(&phdr, sizeof(phdr));			      \
-	}								      \
-}
-#define ELF_CORE_WRITE_EXTRA_DATA					      \
-if ( vsyscall_ehdr ) {							      \
-	const struct elfhdr *const ehdrp = (struct elfhdr *)vsyscall_ehdr;    \
-	const struct elf_phdr *const phdrp =				      \
-		(const struct elf_phdr *) (vsyscall_ehdr + ehdrp->e_phoff);   \
-	int i;								      \
-	for (i = 0; i < ehdrp->e_phnum; ++i) {				      \
-		if (phdrp[i].p_type == PT_LOAD)				      \
-			DUMP_WRITE((void *) phdrp[i].p_vaddr,		      \
-				   phdrp[i].p_filesz);			      \
-	}								      \
-}
-
 #endif

arch/um/sys-i386/elfcore.c

···
+#include <linux/elf.h>
+#include <linux/coredump.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+
+#include <asm/elf.h>
+
+
+Elf32_Half elf_core_extra_phdrs(void)
+{
+	return vsyscall_ehdr ? (((struct elfhdr *)vsyscall_ehdr)->e_phnum) : 0;
+}
+
+int elf_core_write_extra_phdrs(struct file *file, loff_t offset, size_t *size,
+			       unsigned long limit)
+{
+	if ( vsyscall_ehdr ) {
+		const struct elfhdr *const ehdrp =
+			(struct elfhdr *) vsyscall_ehdr;
+		const struct elf_phdr *const phdrp =
+			(const struct elf_phdr *) (vsyscall_ehdr + ehdrp->e_phoff);
+		int i;
+		Elf32_Off ofs = 0;
+
+		for (i = 0; i < ehdrp->e_phnum; ++i) {
+			struct elf_phdr phdr = phdrp[i];
+
+			if (phdr.p_type == PT_LOAD) {
+				ofs = phdr.p_offset = offset;
+				offset += phdr.p_filesz;
+			} else {
+				phdr.p_offset += ofs;
+			}
+			phdr.p_paddr = 0; /* match other core phdrs */
+			*size += sizeof(phdr);
+			if (*size > limit
+			    || !dump_write(file, &phdr, sizeof(phdr)))
+				return 0;
+		}
+	}
+	return 1;
+}
+
+int elf_core_write_extra_data(struct file *file, size_t *size,
+			      unsigned long limit)
+{
+	if ( vsyscall_ehdr ) {
+		const struct elfhdr *const ehdrp =
+			(struct elfhdr *) vsyscall_ehdr;
+		const struct elf_phdr *const phdrp =
+			(const struct elf_phdr *) (vsyscall_ehdr + ehdrp->e_phoff);
+		int i;
+
+		for (i = 0; i < ehdrp->e_phnum; ++i) {
+			if (phdrp[i].p_type == PT_LOAD) {
+				void *addr = (void *) phdrp[i].p_vaddr;
+				size_t filesz = phdrp[i].p_filesz;
+
+				*size += filesz;
+				if (*size > limit
+				    || !dump_write(file, addr, filesz))
+					return 0;
+			}
+		}
+	}
+	return 1;
+}

fs/binfmt_elf.c

···
 	 * Please check DEFAULT_MAX_MAP_COUNT definition when you modify here.
 	 */
 	segs = current->mm->map_count;
-#ifdef ELF_CORE_EXTRA_PHDRS
-	segs += ELF_CORE_EXTRA_PHDRS;
-#endif
+	segs += elf_core_extra_phdrs();
 
 	gate_vma = get_gate_vma(current);
 	if (gate_vma != NULL)
···
 			goto end_coredump;
 	}
 
-#ifdef ELF_CORE_WRITE_EXTRA_PHDRS
-	ELF_CORE_WRITE_EXTRA_PHDRS;
-#endif
+	if (!elf_core_write_extra_phdrs(cprm->file, offset, &size, cprm->limit))
+		goto end_coredump;
 
  	/* write out the notes section */
 	if (!write_note_info(&info, cprm->file, &foffset))
···
 		}
 	}
 
-#ifdef ELF_CORE_WRITE_EXTRA_DATA
-	ELF_CORE_WRITE_EXTRA_DATA;
-#endif
+	if (!elf_core_write_extra_data(cprm->file, &size, cprm->limit))
+		goto end_coredump;
 
 end_coredump:
 	set_fs(fs);

fs/binfmt_elf_fdpic.c

···
 	elf_core_copy_regs(&prstatus->pr_reg, cprm->regs);
 
 	segs = current->mm->map_count;
-#ifdef ELF_CORE_EXTRA_PHDRS
-	segs += ELF_CORE_EXTRA_PHDRS;
-#endif
+	segs += elf_core_extra_phdrs();
 
 	/* Set up header */
 	fill_elf_fdpic_header(elf, segs + 1);	/* including notes section */
···
 			goto end_coredump;
 	}
 
-#ifdef ELF_CORE_WRITE_EXTRA_PHDRS
-	ELF_CORE_WRITE_EXTRA_PHDRS;
-#endif
+	if (!elf_core_write_extra_phdrs(cprm->file, offset, &size, cprm->limit))
+		goto end_coredump;
 
  	/* write out the notes section */
 	for (i = 0; i < numnote; i++)
···
 				    mm_flags) < 0)
 		goto end_coredump;
 
-#ifdef ELF_CORE_WRITE_EXTRA_DATA
-	ELF_CORE_WRITE_EXTRA_DATA;
-#endif
+	if (!elf_core_write_extra_data(cprm->file, &size, cprm->limit))
+		goto end_coredump;
 
 	if (cprm->file->f_pos != offset) {
 		/* Sanity check */

fs/compat_binfmt_elf.c

···
 
 #undef	elfhdr
 #undef	elf_phdr
+#undef	elf_shdr
 #undef	elf_note
 #undef	elf_addr_t
 #define elfhdr		elf32_hdr
 #define elf_phdr	elf32_phdr
+#define elf_shdr	elf32_shdr
 #define elf_note	elf32_note
 #define elf_addr_t	Elf32_Addr
 

include/linux/elf.h

···
 #define elf_phdr	elf32_phdr
 #define elf_note	elf32_note
 #define elf_addr_t	Elf32_Off
+#define Elf_Half	Elf32_Half
 
 #else
 
···
 #define elf_phdr	elf64_phdr
 #define elf_note	elf64_note
 #define elf_addr_t	Elf64_Off
+#define Elf_Half	Elf64_Half
 
 #endif
 

include/linux/elfcore.h

···
 #include <linux/user.h>
 #endif
 #include <linux/ptrace.h>
+#include <linux/elf.h>
+#include <linux/fs.h>
 
 struct elf_siginfo
 {
···
 
 #endif /* __KERNEL__ */
 
+/*
+ * These functions parameterize elf_core_dump in fs/binfmt_elf.c to write out
+ * extra segments containing the gate DSO contents.  Dumping its
+ * contents makes post-mortem fully interpretable later without matching up
+ * the same kernel and hardware config to see what PC values meant.
+ * Dumping its extra ELF program headers includes all the other information
+ * a debugger needs to easily find how the gate DSO was being used.
+ */
+extern Elf_Half elf_core_extra_phdrs(void);
+extern int
+elf_core_write_extra_phdrs(struct file *file, loff_t offset, size_t *size,
+			   unsigned long limit);
+extern int
+elf_core_write_extra_data(struct file *file, size_t *size, unsigned long limit);
 
 #endif /* _LINUX_ELFCORE_H */

kernel/Makefile

···
 obj-$(CONFIG_TASKSTATS) += taskstats.o tsacct.o
 obj-$(CONFIG_TRACEPOINTS) += tracepoint.o
 obj-$(CONFIG_LATENCYTOP) += latencytop.o
+obj-$(CONFIG_BINFMT_ELF) += elfcore.o
+obj-$(CONFIG_COMPAT_BINFMT_ELF) += elfcore.o
+obj-$(CONFIG_BINFMT_ELF_FDPIC) += elfcore.o
 obj-$(CONFIG_FUNCTION_TRACER) += trace/
 obj-$(CONFIG_TRACING) += trace/
 obj-$(CONFIG_X86_DS) += trace/

kernel/elfcore.c

···
+#include <linux/elf.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+
+#include <asm/elf.h>
+
+
+Elf_Half __weak elf_core_extra_phdrs(void)
+{
+	return 0;
+}
+
+int __weak elf_core_write_extra_phdrs(struct file *file, loff_t offset, size_t *size,
+				      unsigned long limit)
+{
+	return 1;
+}
+
+int __weak elf_core_write_extra_data(struct file *file, size_t *size,
+				     unsigned long limit)
+{
+	return 1;
+}