Commit 431dbabf authored by Josh Poimboeuf's avatar Josh Poimboeuf
Browse files

objtool: Add elf_create_data() 



In preparation for the objtool klp diff subcommand, refactor
elf_add_string() by adding a new elf_add_data() helper which allows the
adding of arbitrary data to a section.

Make both interfaces global so they can be used by the upcoming klp diff
code.

Acked-by: default avatarPetr Mladek <pmladek@suse.com>
Tested-by: default avatarJoe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@kernel.org>
parent 243e9638

tools/objtool/elf.c

+47 −19
Original line number Diff line number Diff line
@@ -18,10 +18,11 @@ 
#include <errno.h>

#include <linux/interval_tree_generic.h>

#include <objtool/builtin.h>



#include <objtool/elf.h>

#include <objtool/warn.h>



#define ALIGN_UP(x, align_to) (((x) + ((align_to)-1)) & ~((align_to)-1))



static inline u32 str_hash(const char *str)

{

	return jhash(str, strlen(str), 0);
@@ -763,8 +764,6 @@ static int elf_update_symbol(struct elf *elf, struct section *symtab, 
	return 0;

}



static int elf_add_string(struct elf *elf, struct section *strtab, const char *str);



struct symbol *elf_create_symbol(struct elf *elf, const char *name,

				 struct section *sec, unsigned int bind,

				 unsigned int type, unsigned long offset,
@@ -1100,11 +1099,9 @@ struct elf *elf_open_read(const char *name, int flags) 
	return NULL;

}



static int elf_add_string(struct elf *elf, struct section *strtab, const char *str)

unsigned int elf_add_string(struct elf *elf, struct section *strtab, const char *str)

{

	Elf_Data *data;

	Elf_Scn *s;

	int len;

	unsigned int offset;



	if (!strtab)

		strtab = find_section_by_name(elf, ".strtab");
@@ -1113,28 +1110,59 @@ static int elf_add_string(struct elf *elf, struct section *strtab, const char *s 
		return -1;

	}



	s = elf_getscn(elf->elf, strtab->idx);

	if (!strtab->sh.sh_addralign) {

		ERROR("'%s': invalid sh_addralign", strtab->name);

		return -1;

	}



	offset = ALIGN_UP(strtab->sh.sh_size, strtab->sh.sh_addralign);



	if (!elf_add_data(elf, strtab, str, strlen(str) + 1))

		return -1;



	return offset;

}



void *elf_add_data(struct elf *elf, struct section *sec, const void *data, size_t size)

{

	unsigned long offset;

	Elf_Scn *s;



	if (!sec->sh.sh_addralign) {

		ERROR("'%s': invalid sh_addralign", sec->name);

		return NULL;

	}



	s = elf_getscn(elf->elf, sec->idx);

	if (!s) {

		ERROR_ELF("elf_getscn");

		return -1;

		return NULL;

	}



	data = elf_newdata(s);

	if (!data) {

	sec->data = elf_newdata(s);

	if (!sec->data) {

		ERROR_ELF("elf_newdata");

		return -1;

		return NULL;

	}



	sec->data->d_buf = calloc(1, size);

	if (!sec->data->d_buf) {

		ERROR_GLIBC("calloc");

		return NULL;

	}



	data->d_buf = strdup(str);

	data->d_size = strlen(str) + 1;

	data->d_align = 1;

	if (data)

		memcpy(sec->data->d_buf, data, size);



	len = strtab->sh.sh_size;

	strtab->sh.sh_size += data->d_size;

	sec->data->d_size = size;

	sec->data->d_align = 1;



	mark_sec_changed(elf, strtab, true);

	offset = ALIGN_UP(sec->sh.sh_size, sec->sh.sh_addralign);

	sec->sh.sh_size = offset + size;



	mark_sec_changed(elf, sec, true);



	return len;

	return sec->data->d_buf;

}



struct section *elf_create_section(struct elf *elf, const char *name,

tools/objtool/include/objtool/elf.h

+7 −3
Original line number Diff line number Diff line
@@ -135,6 +135,10 @@ struct symbol *elf_create_section_symbol(struct elf *elf, struct section *sec); 
struct symbol *elf_create_prefix_symbol(struct elf *elf, struct symbol *orig,

					size_t size);



void *elf_add_data(struct elf *elf, struct section *sec, const void *data,

		   size_t size);



unsigned int elf_add_string(struct elf *elf, struct section *strtab, const char *str);



struct reloc *elf_init_reloc_text_sym(struct elf *elf, struct section *sec,

				      unsigned long offset,
@@ -148,9 +152,9 @@ struct reloc *elf_init_reloc_data_sym(struct elf *elf, struct section *sec, 
				      struct symbol *sym,

				      s64 addend);



int elf_write_insn(struct elf *elf, struct section *sec,

		   unsigned long offset, unsigned int len,

		   const char *insn);

int elf_write_insn(struct elf *elf, struct section *sec, unsigned long offset,

		   unsigned int len, const char *insn);



int elf_write(struct elf *elf);

void elf_close(struct elf *elf);