mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-02-07 23:13:34 +00:00
2d80bbc802
blinkenlights now does a pretty good job emulating what happens when binaries boot from BIOS into long mode. So it's been much easier to debug the bare metal process and wrinkle out many issues.
209 lines
7.1 KiB
C
209 lines
7.1 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ This program is free software; you can redistribute it and/or modify │
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│ it under the terms of the GNU General Public License as published by │
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│ the Free Software Foundation; version 2 of the License. │
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│ │
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│ This program is distributed in the hope that it will be useful, but │
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│ WITHOUT ANY WARRANTY; without even the implied warranty of │
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│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
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│ General Public License for more details. │
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│ │
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│ You should have received a copy of the GNU General Public License │
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│ along with this program; if not, write to the Free Software │
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│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
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│ 02110-1301 USA │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/alg/alg.h"
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#include "libc/elf/elf.h"
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#include "libc/elf/struct/sym.h"
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#include "libc/log/check.h"
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#include "libc/log/log.h"
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#include "libc/macros.h"
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#include "libc/mem/mem.h"
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#include "libc/str/str.h"
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#include "tool/build/lib/dis.h"
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bool g_disisprog_disable;
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static int DisSymCompare(const struct DisSym *a, const struct DisSym *b) {
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if (a->addr != b->addr) {
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if (a->addr < b->addr) return -1;
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if (a->addr > b->addr) return +1;
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}
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if (a->rank != b->rank) {
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if (a->rank > b->rank) return -1;
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if (a->rank < b->rank) return +1;
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}
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if (a->unique != b->unique) {
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if (a->unique < b->unique) return -1;
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if (a->unique > b->unique) return +1;
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}
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return 0;
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}
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static void DisLoadElfLoads(struct Dis *d, struct Elf *elf) {
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long i, j, n;
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int64_t addr;
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uint64_t size;
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Elf64_Phdr *phdr;
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j = 0;
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n = elf->ehdr->e_phnum;
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if (d->loads.n < n) {
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d->loads.n = n;
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d->loads.p = realloc(d->loads.p, d->loads.n * sizeof(*d->loads.p));
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CHECK_NOTNULL(d->loads.p);
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}
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for (i = 0; i < n; ++i) {
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phdr = getelfsegmentheaderaddress(elf->ehdr, elf->size, i);
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if (phdr->p_type != PT_LOAD) continue;
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d->loads.p[j].addr = phdr->p_vaddr;
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d->loads.p[j].size = phdr->p_memsz;
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d->loads.p[j].istext = (phdr->p_flags & PF_X) == PF_X;
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++j;
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}
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d->loads.i = j;
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}
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static void DisLoadElfSyms(struct Dis *d, struct Elf *elf) {
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size_t i, j, n;
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int64_t stablen;
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const Elf64_Sym *st, *sym;
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bool isabs, iscode, isweak, islocal, ishidden, isprotected, isfunc, isobject;
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j = 0;
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if ((d->syms.stab = getelfstringtable(elf->ehdr, elf->size)) &&
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(st = getelfsymboltable(elf->ehdr, elf->size, &n))) {
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stablen = (intptr_t)elf->ehdr + elf->size - (intptr_t)d->syms.stab;
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if (d->syms.n < n) {
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d->syms.n = n;
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d->syms.p = realloc(d->syms.p, d->syms.n * sizeof(*d->syms.p));
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CHECK_NOTNULL(d->syms.p);
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}
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for (i = 0; i < n; ++i) {
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if (ELF64_ST_TYPE(st[i].st_info) == STT_SECTION ||
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ELF64_ST_TYPE(st[i].st_info) == STT_FILE || !st[i].st_name ||
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startswith(d->syms.stab + st[i].st_name, "v_") ||
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!(0 <= st[i].st_name && st[i].st_name < stablen) || !st[i].st_value ||
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!(-0x800000000000 <= (int64_t)st[i].st_value &&
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(int64_t)st[i].st_value < 0x800000000000)) {
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continue;
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}
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isabs = st[i].st_shndx == SHN_ABS;
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isweak = ELF64_ST_BIND(st[i].st_info) == STB_WEAK;
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islocal = ELF64_ST_BIND(st[i].st_info) == STB_LOCAL;
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ishidden = st[i].st_other == STV_HIDDEN;
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isprotected = st[i].st_other == STV_PROTECTED;
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isfunc = ELF64_ST_TYPE(st[i].st_info) == STT_FUNC;
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isobject = ELF64_ST_TYPE(st[i].st_info) == STT_OBJECT;
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d->syms.p[j].unique = i;
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d->syms.p[j].size = st[i].st_size;
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d->syms.p[j].name = st[i].st_name;
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d->syms.p[j].addr = st[i].st_value;
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d->syms.p[j].rank =
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-islocal + -isweak + -isabs + isprotected + isobject + isfunc;
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d->syms.p[j].iscode = DisIsText(d, st[i].st_value) ? !isobject : isfunc;
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d->syms.p[j].isabs = isabs;
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++j;
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}
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}
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d->syms.i = j;
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}
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static void DisSortSyms(struct Dis *d) {
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qsort(d->syms.p, d->syms.i, sizeof(struct DisSym), (void *)DisSymCompare);
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}
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static void DisCanonizeSyms(struct Dis *d) {
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int64_t i, j, a;
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if (d->syms.i) {
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i = 1;
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j = 1;
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a = d->syms.p[0].addr;
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do {
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if (d->syms.p[j].addr > a) {
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a = d->syms.p[j].addr;
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if (j > i) {
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d->syms.p[i] = d->syms.p[j];
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}
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++i;
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}
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++j;
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} while (j < d->syms.i);
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d->syms.p = realloc(d->syms.p, sizeof(*d->syms.p) * i);
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d->syms.i = i;
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d->syms.n = i;
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}
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for (i = 0; i < d->syms.i; ++i) {
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DEBUGF("%p-%p %s", d->syms.p[i].addr,
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d->syms.p[i].addr + (d->syms.p[i].size ? d->syms.p[i].size - 1 : 0),
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d->syms.stab + d->syms.p[i].name);
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}
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}
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bool DisIsProg(struct Dis *d, int64_t addr) {
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long i;
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if (g_disisprog_disable) return true;
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for (i = 0; i < d->loads.i; ++i) {
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if (addr >= d->loads.p[i].addr &&
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addr < d->loads.p[i].addr + d->loads.p[i].size) {
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return true;
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}
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}
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return false;
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}
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bool DisIsText(struct Dis *d, int64_t addr) {
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long i;
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for (i = 0; i < d->loads.i; ++i) {
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if (addr >= d->loads.p[i].addr &&
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addr < d->loads.p[i].addr + d->loads.p[i].size) {
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return d->loads.p[i].istext;
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}
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}
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return false;
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}
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long DisFindSym(struct Dis *d, int64_t addr) {
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long l, r, m, n;
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if (DisIsProg(d, addr)) {
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l = 0;
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r = d->syms.i;
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while (l < r) {
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m = (l + r) >> 1;
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if (d->syms.p[m].addr > addr) {
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r = m;
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} else {
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l = m + 1;
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}
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}
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if (r && (addr == d->syms.p[r - 1].addr ||
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(addr > d->syms.p[r - 1].addr &&
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(addr <= d->syms.p[r - 1].addr + d->syms.p[r - 1].size ||
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!d->syms.p[r - 1].size)))) {
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return r - 1;
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}
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}
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return -1;
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}
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long DisFindSymByName(struct Dis *d, const char *s) {
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long i;
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for (i = 0; i < d->syms.i; ++i) {
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if (strcmp(s, d->syms.stab + d->syms.p[i].name) == 0) {
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return i;
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}
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}
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return -1;
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}
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void DisLoadElf(struct Dis *d, struct Elf *elf) {
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LOGF("DisLoadElf");
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if (!elf || !elf->ehdr) return;
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DisLoadElfLoads(d, elf);
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DisLoadElfSyms(d, elf);
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DisSortSyms(d);
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DisCanonizeSyms(d);
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}
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