root/scripts/sortextable.h

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INCLUDED FROM


DEFINITIONS

This source file includes following definitions.
  1. compare_extable
  2. do_func

/*
 * sortextable.h
 *
 * Copyright 2011 - 2012 Cavium, Inc.
 *
 * Some of this code was taken out of recordmcount.h written by:
 *
 * Copyright 2009 John F. Reiser <jreiser@BitWagon.com>.  All rights reserved.
 * Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc.
 *
 *
 * Licensed under the GNU General Public License, version 2 (GPLv2).
 */

#undef extable_ent_size
#undef compare_extable
#undef do_func
#undef Elf_Addr
#undef Elf_Ehdr
#undef Elf_Shdr
#undef Elf_Rel
#undef Elf_Rela
#undef Elf_Sym
#undef ELF_R_SYM
#undef Elf_r_sym
#undef ELF_R_INFO
#undef Elf_r_info
#undef ELF_ST_BIND
#undef ELF_ST_TYPE
#undef fn_ELF_R_SYM
#undef fn_ELF_R_INFO
#undef uint_t
#undef _r
#undef _w

#ifdef SORTEXTABLE_64
# define extable_ent_size       16
# define compare_extable        compare_extable_64
# define do_func                do64
# define Elf_Addr               Elf64_Addr
# define Elf_Ehdr               Elf64_Ehdr
# define Elf_Shdr               Elf64_Shdr
# define Elf_Rel                Elf64_Rel
# define Elf_Rela               Elf64_Rela
# define Elf_Sym                Elf64_Sym
# define ELF_R_SYM              ELF64_R_SYM
# define Elf_r_sym              Elf64_r_sym
# define ELF_R_INFO             ELF64_R_INFO
# define Elf_r_info             Elf64_r_info
# define ELF_ST_BIND            ELF64_ST_BIND
# define ELF_ST_TYPE            ELF64_ST_TYPE
# define fn_ELF_R_SYM           fn_ELF64_R_SYM
# define fn_ELF_R_INFO          fn_ELF64_R_INFO
# define uint_t                 uint64_t
# define _r                     r8
# define _w                     w8
#else
# define extable_ent_size       8
# define compare_extable        compare_extable_32
# define do_func                do32
# define Elf_Addr               Elf32_Addr
# define Elf_Ehdr               Elf32_Ehdr
# define Elf_Shdr               Elf32_Shdr
# define Elf_Rel                Elf32_Rel
# define Elf_Rela               Elf32_Rela
# define Elf_Sym                Elf32_Sym
# define ELF_R_SYM              ELF32_R_SYM
# define Elf_r_sym              Elf32_r_sym
# define ELF_R_INFO             ELF32_R_INFO
# define Elf_r_info             Elf32_r_info
# define ELF_ST_BIND            ELF32_ST_BIND
# define ELF_ST_TYPE            ELF32_ST_TYPE
# define fn_ELF_R_SYM           fn_ELF32_R_SYM
# define fn_ELF_R_INFO          fn_ELF32_R_INFO
# define uint_t                 uint32_t
# define _r                     r
# define _w                     w
#endif

static int compare_extable(const void *a, const void *b)
{
        Elf_Addr av = _r(a);
        Elf_Addr bv = _r(b);

        if (av < bv)
                return -1;
        if (av > bv)
                return 1;
        return 0;
}

static void
do_func(Elf_Ehdr *ehdr, char const *const fname, table_sort_t custom_sort)
{
        Elf_Shdr *shdr;
        Elf_Shdr *shstrtab_sec;
        Elf_Shdr *strtab_sec = NULL;
        Elf_Shdr *symtab_sec = NULL;
        Elf_Shdr *extab_sec = NULL;
        Elf_Sym *sym;
        const Elf_Sym *symtab;
        Elf32_Word *symtab_shndx_start = NULL;
        Elf_Sym *sort_needed_sym;
        Elf_Shdr *sort_needed_sec;
        Elf_Rel *relocs = NULL;
        int relocs_size = 0;
        uint32_t *sort_done_location;
        const char *secstrtab;
        const char *strtab;
        char *extab_image;
        int extab_index = 0;
        int i;
        int idx;
        unsigned int num_sections;
        unsigned int secindex_strings;

        shdr = (Elf_Shdr *)((char *)ehdr + _r(&ehdr->e_shoff));

        num_sections = r2(&ehdr->e_shnum);
        if (num_sections == SHN_UNDEF)
                num_sections = _r(&shdr[0].sh_size);

        secindex_strings = r2(&ehdr->e_shstrndx);
        if (secindex_strings == SHN_XINDEX)
                secindex_strings = r(&shdr[0].sh_link);

        shstrtab_sec = shdr + secindex_strings;
        secstrtab = (const char *)ehdr + _r(&shstrtab_sec->sh_offset);
        for (i = 0; i < num_sections; i++) {
                idx = r(&shdr[i].sh_name);
                if (strcmp(secstrtab + idx, "__ex_table") == 0) {
                        extab_sec = shdr + i;
                        extab_index = i;
                }
                if ((r(&shdr[i].sh_type) == SHT_REL ||
                     r(&shdr[i].sh_type) == SHT_RELA) &&
                    r(&shdr[i].sh_info) == extab_index) {
                        relocs = (void *)ehdr + _r(&shdr[i].sh_offset);
                        relocs_size = _r(&shdr[i].sh_size);
                }
                if (strcmp(secstrtab + idx, ".symtab") == 0)
                        symtab_sec = shdr + i;
                if (strcmp(secstrtab + idx, ".strtab") == 0)
                        strtab_sec = shdr + i;
                if (r(&shdr[i].sh_type) == SHT_SYMTAB_SHNDX)
                        symtab_shndx_start = (Elf32_Word *)(
                                (const char *)ehdr + _r(&shdr[i].sh_offset));
        }
        if (strtab_sec == NULL) {
                fprintf(stderr, "no .strtab in  file: %s\n", fname);
                fail_file();
        }
        if (symtab_sec == NULL) {
                fprintf(stderr, "no .symtab in  file: %s\n", fname);
                fail_file();
        }
        symtab = (const Elf_Sym *)((const char *)ehdr +
                                   _r(&symtab_sec->sh_offset));
        if (extab_sec == NULL) {
                fprintf(stderr, "no __ex_table in  file: %s\n", fname);
                fail_file();
        }
        strtab = (const char *)ehdr + _r(&strtab_sec->sh_offset);

        extab_image = (void *)ehdr + _r(&extab_sec->sh_offset);

        if (custom_sort) {
                custom_sort(extab_image, _r(&extab_sec->sh_size));
        } else {
                int num_entries = _r(&extab_sec->sh_size) / extable_ent_size;
                qsort(extab_image, num_entries,
                      extable_ent_size, compare_extable);
        }
        /* If there were relocations, we no longer need them. */
        if (relocs)
                memset(relocs, 0, relocs_size);

        /* find main_extable_sort_needed */
        sort_needed_sym = NULL;
        for (i = 0; i < _r(&symtab_sec->sh_size) / sizeof(Elf_Sym); i++) {
                sym = (void *)ehdr + _r(&symtab_sec->sh_offset);
                sym += i;
                if (ELF_ST_TYPE(sym->st_info) != STT_OBJECT)
                        continue;
                idx = r(&sym->st_name);
                if (strcmp(strtab + idx, "main_extable_sort_needed") == 0) {
                        sort_needed_sym = sym;
                        break;
                }
        }
        if (sort_needed_sym == NULL) {
                fprintf(stderr,
                        "no main_extable_sort_needed symbol in  file: %s\n",
                        fname);
                fail_file();
        }
        sort_needed_sec = &shdr[get_secindex(r2(&sym->st_shndx),
                                             sort_needed_sym - symtab,
                                             symtab_shndx_start)];
        sort_done_location = (void *)ehdr +
                _r(&sort_needed_sec->sh_offset) +
                _r(&sort_needed_sym->st_value) -
                _r(&sort_needed_sec->sh_addr);

#if 0
        printf("sort done marker at %lx\n",
               (unsigned long)((char *)sort_done_location - (char *)ehdr));
#endif
        /* We sorted it, clear the flag. */
        w(0, sort_done_location);
}

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