readelf: Add several sanity checks.
Should resolve several reported issues. Fixes #245 Fixes #244 Fixes #243
This commit is contained in:
K. Lange
parent
2391009167
commit
5d36d27bb9
147
apps/readelf.c
147
apps/readelf.c
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@ -20,7 +20,11 @@
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#include <stdlib.h>
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#include <errno.h>
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#include <getopt.h>
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#ifdef __toaru__
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#include <kernel/elf.h>
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#else
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#include "base/usr/include/kernel/elf.h"
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#endif
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#define SHOW_FILE_HEADER 0x0001
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#define SHOW_SECTION_HEADERS 0x0002
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@ -279,14 +283,14 @@ static char * dynamicTagToStr(Elf64_Dyn * dynEntry, char * dynstr) {
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break;
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case 0x6ffffff9:
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name = "(RELACOUNT)";
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sprintf(extra, "%ld", dynEntry->d_un.d_val);
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snprintf(extra, 500, "%ld", dynEntry->d_un.d_val);
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break;
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default:
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name = "(unknown)";
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break;
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}
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sprintf(buf,"%-15s %s", name, extra);
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snprintf(buf, 1024, "%-15s %s", name, extra);
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return buf;
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}
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@ -431,6 +435,25 @@ static int usage(char * argv[]) {
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return 1;
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}
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struct StringTable {
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size_t length;
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char strings[];
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};
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static struct StringTable * load_string_table(FILE * f, Elf64_Shdr * header) {
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struct StringTable * out = malloc(sizeof(struct StringTable) + header->sh_size + 1);
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out->length = header->sh_size;
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fseek(f, header->sh_offset, SEEK_SET);
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fread(out->strings, header->sh_size, 1, f);
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out->strings[out->length] = 0;
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return out;
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}
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static const char * string_from_table(struct StringTable * table, size_t offset) {
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if (offset >= table->length) return "(out of range)";
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return table->strings + offset;
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}
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int main(int argc, char * argv[]) {
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static struct option long_opts[] = {
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@ -568,9 +591,7 @@ int main(int argc, char * argv[]) {
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fseek(f, header.e_shoff + header.e_shentsize * header.e_shstrndx, SEEK_SET);
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fread(&shstr_hdr, sizeof(Elf64_Shdr), 1, f);
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char * stringTable = malloc(shstr_hdr.sh_size);
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fseek(f, shstr_hdr.sh_offset, SEEK_SET);
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fread(stringTable, shstr_hdr.sh_size, 1, f);
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struct StringTable * stringTable = load_string_table(f, &shstr_hdr);
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/**
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* Section Headers
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@ -585,7 +606,7 @@ int main(int argc, char * argv[]) {
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fread(§ionHeader, sizeof(Elf64_Shdr), 1, f);
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printf(" [%2d] %-17.17s %-16.16s %016lx %08lx\n",
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i, stringTable + sectionHeader.sh_name, sectionHeaderTypeToStr(sectionHeader.sh_type),
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i, string_from_table(stringTable, sectionHeader.sh_name), sectionHeaderTypeToStr(sectionHeader.sh_type),
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sectionHeader.sh_addr, sectionHeader.sh_offset);
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printf(" %016lx %016lx %4ld %6d %5d %5ld\n",
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sectionHeader.sh_size, sectionHeader.sh_entsize, sectionHeader.sh_flags,
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@ -634,6 +655,11 @@ int main(int argc, char * argv[]) {
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Elf64_Shdr sectionHeader;
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fread(§ionHeader, sizeof(Elf64_Shdr), 1, f);
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if (sectionHeader.sh_size > 0x40000000) {
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/* Suspiciously large section header... */
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continue;
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}
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/* I think there should only be one of these... */
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switch (sectionHeader.sh_type) {
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case SHT_DYNAMIC:
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@ -671,7 +697,7 @@ int main(int argc, char * argv[]) {
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case SHT_RELA:
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if (show_bits & SHOW_RELOCATIONS) {
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printf("\nRelocation section '%s' at offset 0x%lx contains %ld entries.\n",
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stringTable + sectionHeader.sh_name, sectionHeader.sh_offset,
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string_from_table(stringTable, sectionHeader.sh_name), sectionHeader.sh_offset,
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sectionHeader.sh_size / sizeof(Elf64_Rela));
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printf(" Offset Info Type Sym. Value Sym. Name + Addend\n");
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@ -692,9 +718,7 @@ int main(int argc, char * argv[]) {
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Elf64_Shdr shdr_strtab;
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fseek(f, header.e_shoff + header.e_shentsize * shdr_symtab.sh_link, SEEK_SET);
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fread(&shdr_strtab, sizeof(Elf64_Shdr), 1, f);
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char * strtab = malloc(shdr_strtab.sh_size);
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fseek(f, shdr_strtab.sh_offset, SEEK_SET);
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fread(strtab, shdr_strtab.sh_size, 1, f);
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struct StringTable * strtab = load_string_table(f, &shdr_strtab);
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/* Load relocations from file */
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Elf64_Rela * relocations = malloc(sectionHeader.sh_size);
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@ -703,53 +727,56 @@ int main(int argc, char * argv[]) {
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for (unsigned int i = 0; i < sectionHeader.sh_size / sizeof(Elf64_Rela); ++i) {
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Elf64_Shdr shdr;
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Elf64_Sym * this = &symtab[ELF64_R_SYM(relocations[i].r_info)];
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char * symName;
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/* Get symbol name for this relocation */
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if ((this->st_info & 0xF) == STT_SECTION) {
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fseek(f, header.e_shoff + header.e_shentsize * this->st_shndx, SEEK_SET);
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fread(&shdr, sizeof(Elf64_Shdr), 1, f);
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symName = stringTable + shdr.sh_name;
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} else {
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symName = strtab + this->st_name;
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}
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/* Get the value currently in the section data */
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size_t offset = ELF64_R_SYM(relocations[i].r_info);
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Elf64_Xword value = 0;
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int valueSize = sizeOfRelocationValue(ELF64_R_TYPE(relocations[i].r_info));
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fseek(f, shdr_this.sh_offset + relocations[i].r_offset, SEEK_SET);
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switch (valueSize) {
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case 8:
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{
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uint64_t val;
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fread(&val, valueSize, 1, f);
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value = val;
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const char * symName = "(null)";
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if (offset < shdr_symtab.sh_size) {
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Elf64_Sym * this = &symtab[offset];
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/* Get symbol name for this relocation */
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if ((this->st_info & 0xF) == STT_SECTION) {
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fseek(f, header.e_shoff + header.e_shentsize * this->st_shndx, SEEK_SET);
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fread(&shdr, sizeof(Elf64_Shdr), 1, f);
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symName = string_from_table(stringTable, shdr.sh_name);
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} else {
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symName = string_from_table(strtab, this->st_name);
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}
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/* Get the value currently in the section data */
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int valueSize = sizeOfRelocationValue(ELF64_R_TYPE(relocations[i].r_info));
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fseek(f, shdr_this.sh_offset + relocations[i].r_offset, SEEK_SET);
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switch (valueSize) {
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case 8:
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{
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uint64_t val;
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fread(&val, valueSize, 1, f);
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value = val;
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break;
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}
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case 4:
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{
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uint32_t val;
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fread(&val, valueSize, 1, f);
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value = val;
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break;
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}
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case 2:
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{
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uint16_t val;
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fread(&val, valueSize, 1, f);
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value = val;
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break;
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}
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case 1:
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{
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uint8_t val;
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fread(&val, valueSize, 1, f);
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value = val;
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break;
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}
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default:
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break;
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}
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case 4:
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{
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uint32_t val;
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fread(&val, valueSize, 1, f);
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value = val;
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break;
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}
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case 2:
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{
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uint16_t val;
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fread(&val, valueSize, 1, f);
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value = val;
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break;
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}
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case 1:
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{
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uint8_t val;
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fread(&val, valueSize, 1, f);
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value = val;
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break;
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}
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default:
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break;
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}
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}
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printf("%012lx %012lx %-15.15s %016lx %s + %lx\n",
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@ -769,7 +796,7 @@ int main(int argc, char * argv[]) {
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case SHT_SYMTAB:
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if (show_bits & SHOW_SYMBOLS) {
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printf("\nSymbol table '%s' contains %ld entries.\n",
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stringTable + sectionHeader.sh_name,
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string_from_table(stringTable, sectionHeader.sh_name),
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sectionHeader.sh_size / sizeof(Elf64_Sym));
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printf(" Num: Value Size Type Bind Vis Ndx Name\n");
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@ -780,9 +807,7 @@ int main(int argc, char * argv[]) {
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Elf64_Shdr shdr_strtab;
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fseek(f, header.e_shoff + header.e_shentsize * sectionHeader.sh_link, SEEK_SET);
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fread(&shdr_strtab, sizeof(Elf64_Shdr), 1, f);
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char * strtab = malloc(shdr_strtab.sh_size);
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fseek(f, shdr_strtab.sh_offset, SEEK_SET);
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fread(strtab, shdr_strtab.sh_size, 1, f);
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struct StringTable * strtab = load_string_table(f, &shdr_strtab);
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for (unsigned int i = 0; i < sectionHeader.sh_size / sizeof(Elf64_Sym); ++i) {
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printf("%6u: %016lx %6lu %-7.7s %-6.6s %-4d %6d %s\n",
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@ -791,7 +816,7 @@ int main(int argc, char * argv[]) {
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symbolBindToStr(symtab[i].st_info >> 4),
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symtab[i].st_other,
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symtab[i].st_shndx,
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strtab + symtab[i].st_name);
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string_from_table(strtab, symtab[i].st_name));
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}
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free(strtab);
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@ -803,6 +828,8 @@ int main(int argc, char * argv[]) {
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}
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}
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free(stringTable);
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}
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return out;
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