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fa7f7e7354
Adds a test for minimal jit_write_elf functionality. Committer testing: # perf test jit 61: Test jit_write_elf : Ok # # perf test -v jit 61: Test jit_write_elf : --- start --- test child forked, pid 10460 Writing jit code to: /tmp/perf-test-KqxURR test child finished with 0 ---- end ---- Test jit_write_elf: Ok # Committer notes: Fix up the case where HAVE_JITDUMP is no defined. Signed-off-by: Ian Rogers <irogers@google.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexios Zavras <alexios.zavras@intel.com> Cc: Allison Randal <allison@lohutok.net> Cc: Florian Fainelli <f.fainelli@gmail.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Leo Yan <leo.yan@linaro.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Michael Petlan <mpetlan@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Song Liu <songliubraving@fb.com> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lore.kernel.org/lkml/20191126235913.41855-1-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
509 lines
10 KiB
C
509 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* genelf.c
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* Copyright (C) 2014, Google, Inc
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*
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* Contributed by:
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* Stephane Eranian <eranian@gmail.com>
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*/
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#include <sys/types.h>
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#include <stddef.h>
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#include <libelf.h>
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#include <string.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <inttypes.h>
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#include <fcntl.h>
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#include <err.h>
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#ifdef HAVE_DWARF_SUPPORT
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#include <dwarf.h>
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#endif
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#include "genelf.h"
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#include "../util/jitdump.h"
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#include <linux/compiler.h>
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#ifndef NT_GNU_BUILD_ID
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#define NT_GNU_BUILD_ID 3
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#endif
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#define BUILD_ID_URANDOM /* different uuid for each run */
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#ifdef HAVE_LIBCRYPTO
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#define BUILD_ID_MD5
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#undef BUILD_ID_SHA /* does not seem to work well when linked with Java */
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#undef BUILD_ID_URANDOM /* different uuid for each run */
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#ifdef BUILD_ID_SHA
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#include <openssl/sha.h>
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#endif
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#ifdef BUILD_ID_MD5
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#include <openssl/md5.h>
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#endif
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#endif
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typedef struct {
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unsigned int namesz; /* Size of entry's owner string */
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unsigned int descsz; /* Size of the note descriptor */
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unsigned int type; /* Interpretation of the descriptor */
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char name[0]; /* Start of the name+desc data */
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} Elf_Note;
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struct options {
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char *output;
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int fd;
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};
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static char shd_string_table[] = {
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0,
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'.', 't', 'e', 'x', 't', 0, /* 1 */
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'.', 's', 'h', 's', 't', 'r', 't', 'a', 'b', 0, /* 7 */
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'.', 's', 'y', 'm', 't', 'a', 'b', 0, /* 17 */
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'.', 's', 't', 'r', 't', 'a', 'b', 0, /* 25 */
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'.', 'n', 'o', 't', 'e', '.', 'g', 'n', 'u', '.', 'b', 'u', 'i', 'l', 'd', '-', 'i', 'd', 0, /* 33 */
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'.', 'd', 'e', 'b', 'u', 'g', '_', 'l', 'i', 'n', 'e', 0, /* 52 */
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'.', 'd', 'e', 'b', 'u', 'g', '_', 'i', 'n', 'f', 'o', 0, /* 64 */
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'.', 'd', 'e', 'b', 'u', 'g', '_', 'a', 'b', 'b', 'r', 'e', 'v', 0, /* 76 */
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'.', 'e', 'h', '_', 'f', 'r', 'a', 'm', 'e', '_', 'h', 'd', 'r', 0, /* 90 */
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'.', 'e', 'h', '_', 'f', 'r', 'a', 'm', 'e', 0, /* 104 */
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};
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static struct buildid_note {
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Elf_Note desc; /* descsz: size of build-id, must be multiple of 4 */
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char name[4]; /* GNU\0 */
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char build_id[20];
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} bnote;
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static Elf_Sym symtab[]={
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/* symbol 0 MUST be the undefined symbol */
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{ .st_name = 0, /* index in sym_string table */
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.st_info = ELF_ST_TYPE(STT_NOTYPE),
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.st_shndx = 0, /* for now */
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.st_value = 0x0,
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.st_other = ELF_ST_VIS(STV_DEFAULT),
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.st_size = 0,
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},
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{ .st_name = 1, /* index in sym_string table */
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.st_info = ELF_ST_BIND(STB_LOCAL) | ELF_ST_TYPE(STT_FUNC),
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.st_shndx = 1,
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.st_value = 0, /* for now */
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.st_other = ELF_ST_VIS(STV_DEFAULT),
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.st_size = 0, /* for now */
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}
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};
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#ifdef BUILD_ID_URANDOM
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static void
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gen_build_id(struct buildid_note *note,
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unsigned long load_addr __maybe_unused,
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const void *code __maybe_unused,
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size_t csize __maybe_unused)
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{
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int fd;
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size_t sz = sizeof(note->build_id);
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ssize_t sret;
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fd = open("/dev/urandom", O_RDONLY);
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if (fd == -1)
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err(1, "cannot access /dev/urandom for buildid");
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sret = read(fd, note->build_id, sz);
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close(fd);
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if (sret != (ssize_t)sz)
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memset(note->build_id, 0, sz);
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}
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#endif
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#ifdef BUILD_ID_SHA
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static void
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gen_build_id(struct buildid_note *note,
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unsigned long load_addr __maybe_unused,
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const void *code,
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size_t csize)
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{
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if (sizeof(note->build_id) < SHA_DIGEST_LENGTH)
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errx(1, "build_id too small for SHA1");
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SHA1(code, csize, (unsigned char *)note->build_id);
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}
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#endif
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#ifdef BUILD_ID_MD5
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static void
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gen_build_id(struct buildid_note *note, unsigned long load_addr, const void *code, size_t csize)
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{
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MD5_CTX context;
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if (sizeof(note->build_id) < 16)
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errx(1, "build_id too small for MD5");
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MD5_Init(&context);
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MD5_Update(&context, &load_addr, sizeof(load_addr));
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MD5_Update(&context, code, csize);
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MD5_Final((unsigned char *)note->build_id, &context);
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}
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#endif
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static int
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jit_add_eh_frame_info(Elf *e, void* unwinding, uint64_t unwinding_header_size,
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uint64_t unwinding_size, uint64_t base_offset)
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{
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Elf_Data *d;
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Elf_Scn *scn;
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Elf_Shdr *shdr;
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uint64_t unwinding_table_size = unwinding_size - unwinding_header_size;
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/*
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* setup eh_frame section
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*/
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scn = elf_newscn(e);
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if (!scn) {
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warnx("cannot create section");
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return -1;
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}
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d = elf_newdata(scn);
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if (!d) {
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warnx("cannot get new data");
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return -1;
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}
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d->d_align = 8;
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d->d_off = 0LL;
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d->d_buf = unwinding;
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d->d_type = ELF_T_BYTE;
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d->d_size = unwinding_table_size;
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d->d_version = EV_CURRENT;
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shdr = elf_getshdr(scn);
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if (!shdr) {
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warnx("cannot get section header");
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return -1;
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}
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shdr->sh_name = 104;
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shdr->sh_type = SHT_PROGBITS;
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shdr->sh_addr = base_offset;
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shdr->sh_flags = SHF_ALLOC;
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shdr->sh_entsize = 0;
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/*
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* setup eh_frame_hdr section
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*/
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scn = elf_newscn(e);
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if (!scn) {
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warnx("cannot create section");
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return -1;
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}
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d = elf_newdata(scn);
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if (!d) {
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warnx("cannot get new data");
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return -1;
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}
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d->d_align = 4;
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d->d_off = 0LL;
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d->d_buf = unwinding + unwinding_table_size;
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d->d_type = ELF_T_BYTE;
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d->d_size = unwinding_header_size;
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d->d_version = EV_CURRENT;
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shdr = elf_getshdr(scn);
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if (!shdr) {
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warnx("cannot get section header");
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return -1;
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}
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shdr->sh_name = 90;
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shdr->sh_type = SHT_PROGBITS;
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shdr->sh_addr = base_offset + unwinding_table_size;
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shdr->sh_flags = SHF_ALLOC;
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shdr->sh_entsize = 0;
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return 0;
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}
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/*
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* fd: file descriptor open for writing for the output file
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* load_addr: code load address (could be zero, just used for buildid)
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* sym: function name (for native code - used as the symbol)
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* code: the native code
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* csize: the code size in bytes
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*/
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int
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jit_write_elf(int fd, uint64_t load_addr, const char *sym,
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const void *code, int csize,
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void *debug __maybe_unused, int nr_debug_entries __maybe_unused,
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void *unwinding, uint64_t unwinding_header_size, uint64_t unwinding_size)
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{
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Elf *e;
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Elf_Data *d;
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Elf_Scn *scn;
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Elf_Ehdr *ehdr;
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Elf_Shdr *shdr;
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uint64_t eh_frame_base_offset;
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char *strsym = NULL;
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int symlen;
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int retval = -1;
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if (elf_version(EV_CURRENT) == EV_NONE) {
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warnx("ELF initialization failed");
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return -1;
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}
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e = elf_begin(fd, ELF_C_WRITE, NULL);
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if (!e) {
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warnx("elf_begin failed");
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goto error;
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}
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/*
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* setup ELF header
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*/
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ehdr = elf_newehdr(e);
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if (!ehdr) {
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warnx("cannot get ehdr");
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goto error;
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}
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ehdr->e_ident[EI_DATA] = GEN_ELF_ENDIAN;
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ehdr->e_ident[EI_CLASS] = GEN_ELF_CLASS;
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ehdr->e_machine = GEN_ELF_ARCH;
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ehdr->e_type = ET_DYN;
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ehdr->e_entry = GEN_ELF_TEXT_OFFSET;
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ehdr->e_version = EV_CURRENT;
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ehdr->e_shstrndx= unwinding ? 4 : 2; /* shdr index for section name */
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/*
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* setup text section
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*/
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scn = elf_newscn(e);
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if (!scn) {
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warnx("cannot create section");
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goto error;
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}
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d = elf_newdata(scn);
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if (!d) {
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warnx("cannot get new data");
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goto error;
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}
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d->d_align = 16;
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d->d_off = 0LL;
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d->d_buf = (void *)code;
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d->d_type = ELF_T_BYTE;
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d->d_size = csize;
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d->d_version = EV_CURRENT;
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shdr = elf_getshdr(scn);
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if (!shdr) {
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warnx("cannot get section header");
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goto error;
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}
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shdr->sh_name = 1;
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shdr->sh_type = SHT_PROGBITS;
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shdr->sh_addr = GEN_ELF_TEXT_OFFSET;
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shdr->sh_flags = SHF_EXECINSTR | SHF_ALLOC;
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shdr->sh_entsize = 0;
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/*
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* Setup .eh_frame_hdr and .eh_frame
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*/
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if (unwinding) {
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eh_frame_base_offset = ALIGN_8(GEN_ELF_TEXT_OFFSET + csize);
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retval = jit_add_eh_frame_info(e, unwinding,
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unwinding_header_size, unwinding_size,
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eh_frame_base_offset);
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if (retval)
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goto error;
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}
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/*
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* setup section headers string table
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*/
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scn = elf_newscn(e);
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if (!scn) {
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warnx("cannot create section");
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goto error;
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}
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d = elf_newdata(scn);
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if (!d) {
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warnx("cannot get new data");
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goto error;
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}
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d->d_align = 1;
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d->d_off = 0LL;
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d->d_buf = shd_string_table;
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d->d_type = ELF_T_BYTE;
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d->d_size = sizeof(shd_string_table);
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d->d_version = EV_CURRENT;
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shdr = elf_getshdr(scn);
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if (!shdr) {
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warnx("cannot get section header");
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goto error;
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}
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shdr->sh_name = 7; /* offset of '.shstrtab' in shd_string_table */
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shdr->sh_type = SHT_STRTAB;
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shdr->sh_flags = 0;
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shdr->sh_entsize = 0;
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/*
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* setup symtab section
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*/
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symtab[1].st_size = csize;
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symtab[1].st_value = GEN_ELF_TEXT_OFFSET;
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scn = elf_newscn(e);
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if (!scn) {
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warnx("cannot create section");
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goto error;
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}
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d = elf_newdata(scn);
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if (!d) {
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warnx("cannot get new data");
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goto error;
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}
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d->d_align = 8;
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d->d_off = 0LL;
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d->d_buf = symtab;
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d->d_type = ELF_T_SYM;
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d->d_size = sizeof(symtab);
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d->d_version = EV_CURRENT;
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shdr = elf_getshdr(scn);
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if (!shdr) {
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warnx("cannot get section header");
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goto error;
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}
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shdr->sh_name = 17; /* offset of '.symtab' in shd_string_table */
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shdr->sh_type = SHT_SYMTAB;
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shdr->sh_flags = 0;
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shdr->sh_entsize = sizeof(Elf_Sym);
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shdr->sh_link = unwinding ? 6 : 4; /* index of .strtab section */
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/*
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* setup symbols string table
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* 2 = 1 for 0 in 1st entry, 1 for the 0 at end of symbol for 2nd entry
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*/
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symlen = 2 + strlen(sym);
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strsym = calloc(1, symlen);
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if (!strsym) {
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warnx("cannot allocate strsym");
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goto error;
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}
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strcpy(strsym + 1, sym);
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scn = elf_newscn(e);
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if (!scn) {
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warnx("cannot create section");
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goto error;
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}
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d = elf_newdata(scn);
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if (!d) {
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warnx("cannot get new data");
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goto error;
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}
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d->d_align = 1;
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d->d_off = 0LL;
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d->d_buf = strsym;
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d->d_type = ELF_T_BYTE;
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d->d_size = symlen;
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d->d_version = EV_CURRENT;
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shdr = elf_getshdr(scn);
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if (!shdr) {
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warnx("cannot get section header");
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goto error;
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}
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shdr->sh_name = 25; /* offset in shd_string_table */
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shdr->sh_type = SHT_STRTAB;
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shdr->sh_flags = 0;
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shdr->sh_entsize = 0;
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/*
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* setup build-id section
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*/
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scn = elf_newscn(e);
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if (!scn) {
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warnx("cannot create section");
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goto error;
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}
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d = elf_newdata(scn);
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if (!d) {
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warnx("cannot get new data");
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goto error;
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}
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/*
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* build-id generation
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*/
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gen_build_id(&bnote, load_addr, code, csize);
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bnote.desc.namesz = sizeof(bnote.name); /* must include 0 termination */
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bnote.desc.descsz = sizeof(bnote.build_id);
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bnote.desc.type = NT_GNU_BUILD_ID;
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strcpy(bnote.name, "GNU");
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d->d_align = 4;
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d->d_off = 0LL;
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d->d_buf = &bnote;
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d->d_type = ELF_T_BYTE;
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d->d_size = sizeof(bnote);
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d->d_version = EV_CURRENT;
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shdr = elf_getshdr(scn);
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if (!shdr) {
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warnx("cannot get section header");
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goto error;
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}
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shdr->sh_name = 33; /* offset in shd_string_table */
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shdr->sh_type = SHT_NOTE;
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shdr->sh_addr = 0x0;
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shdr->sh_flags = SHF_ALLOC;
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shdr->sh_size = sizeof(bnote);
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shdr->sh_entsize = 0;
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#ifdef HAVE_DWARF_SUPPORT
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if (debug && nr_debug_entries) {
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retval = jit_add_debug_info(e, load_addr, debug, nr_debug_entries);
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if (retval)
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goto error;
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} else
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#endif
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{
|
|
if (elf_update(e, ELF_C_WRITE) < 0) {
|
|
warnx("elf_update 4 failed");
|
|
goto error;
|
|
}
|
|
}
|
|
|
|
retval = 0;
|
|
error:
|
|
(void)elf_end(e);
|
|
|
|
free(strsym);
|
|
|
|
|
|
return retval;
|
|
}
|