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-rw-r--r--tools/perf/util/genelf.c442
1 files changed, 442 insertions, 0 deletions
diff --git a/tools/perf/util/genelf.c b/tools/perf/util/genelf.c
new file mode 100644
index 000000000000..145f8116ef56
--- /dev/null
+++ b/tools/perf/util/genelf.c
@@ -0,0 +1,442 @@
+/*
+ * genelf.c
+ * Copyright (C) 2014, Google, Inc
+ *
+ * Contributed by:
+ * Stephane Eranian <eranian@gmail.com>
+ *
+ * Released under the GPL v2. (and only v2, not any later version)
+ */
+
+#include <sys/types.h>
+#include <stdio.h>
+#include <getopt.h>
+#include <stddef.h>
+#include <libelf.h>
+#include <string.h>
+#include <stdlib.h>
+#include <inttypes.h>
+#include <limits.h>
+#include <fcntl.h>
+#include <err.h>
+#include <dwarf.h>
+
+#include "perf.h"
+#include "genelf.h"
+#include "../util/jitdump.h"
+
+#define JVMTI
+
+#define BUILD_ID_URANDOM /* different uuid for each run */
+
+#ifdef HAVE_LIBCRYPTO
+
+#define BUILD_ID_MD5
+#undef BUILD_ID_SHA /* does not seem to work well when linked with Java */
+#undef BUILD_ID_URANDOM /* different uuid for each run */
+
+#ifdef BUILD_ID_SHA
+#include <openssl/sha.h>
+#endif
+
+#ifdef BUILD_ID_MD5
+#include <openssl/md5.h>
+#endif
+#endif
+
+
+typedef struct {
+ unsigned int namesz; /* Size of entry's owner string */
+ unsigned int descsz; /* Size of the note descriptor */
+ unsigned int type; /* Interpretation of the descriptor */
+ char name[0]; /* Start of the name+desc data */
+} Elf_Note;
+
+struct options {
+ char *output;
+ int fd;
+};
+
+static char shd_string_table[] = {
+ 0,
+ '.', 't', 'e', 'x', 't', 0, /* 1 */
+ '.', 's', 'h', 's', 't', 'r', 't', 'a', 'b', 0, /* 7 */
+ '.', 's', 'y', 'm', 't', 'a', 'b', 0, /* 17 */
+ '.', 's', 't', 'r', 't', 'a', 'b', 0, /* 25 */
+ '.', 'n', 'o', 't', 'e', '.', 'g', 'n', 'u', '.', 'b', 'u', 'i', 'l', 'd', '-', 'i', 'd', 0, /* 33 */
+ '.', 'd', 'e', 'b', 'u', 'g', '_', 'l', 'i', 'n', 'e', 0, /* 52 */
+ '.', 'd', 'e', 'b', 'u', 'g', '_', 'i', 'n', 'f', 'o', 0, /* 64 */
+ '.', 'd', 'e', 'b', 'u', 'g', '_', 'a', 'b', 'b', 'r', 'e', 'v', 0, /* 76 */
+};
+
+static struct buildid_note {
+ Elf_Note desc; /* descsz: size of build-id, must be multiple of 4 */
+ char name[4]; /* GNU\0 */
+ char build_id[20];
+} bnote;
+
+static Elf_Sym symtab[]={
+ /* symbol 0 MUST be the undefined symbol */
+ { .st_name = 0, /* index in sym_string table */
+ .st_info = ELF_ST_TYPE(STT_NOTYPE),
+ .st_shndx = 0, /* for now */
+ .st_value = 0x0,
+ .st_other = ELF_ST_VIS(STV_DEFAULT),
+ .st_size = 0,
+ },
+ { .st_name = 1, /* index in sym_string table */
+ .st_info = ELF_ST_BIND(STB_LOCAL) | ELF_ST_TYPE(STT_FUNC),
+ .st_shndx = 1,
+ .st_value = 0, /* for now */
+ .st_other = ELF_ST_VIS(STV_DEFAULT),
+ .st_size = 0, /* for now */
+ }
+};
+
+#ifdef BUILD_ID_URANDOM
+static void
+gen_build_id(struct buildid_note *note,
+ unsigned long load_addr __maybe_unused,
+ const void *code __maybe_unused,
+ size_t csize __maybe_unused)
+{
+ int fd;
+ size_t sz = sizeof(note->build_id);
+ ssize_t sret;
+
+ fd = open("/dev/urandom", O_RDONLY);
+ if (fd == -1)
+ err(1, "cannot access /dev/urandom for builid");
+
+ sret = read(fd, note->build_id, sz);
+
+ close(fd);
+
+ if (sret != (ssize_t)sz)
+ memset(note->build_id, 0, sz);
+}
+#endif
+
+#ifdef BUILD_ID_SHA
+static void
+gen_build_id(struct buildid_note *note,
+ unsigned long load_addr __maybe_unused,
+ const void *code,
+ size_t csize)
+{
+ if (sizeof(note->build_id) < SHA_DIGEST_LENGTH)
+ errx(1, "build_id too small for SHA1");
+
+ SHA1(code, csize, (unsigned char *)note->build_id);
+}
+#endif
+
+#ifdef BUILD_ID_MD5
+static void
+gen_build_id(struct buildid_note *note, unsigned long load_addr, const void *code, size_t csize)
+{
+ MD5_CTX context;
+
+ if (sizeof(note->build_id) < 16)
+ errx(1, "build_id too small for MD5");
+
+ MD5_Init(&context);
+ MD5_Update(&context, &load_addr, sizeof(load_addr));
+ MD5_Update(&context, code, csize);
+ MD5_Final((unsigned char *)note->build_id, &context);
+}
+#endif
+
+/*
+ * fd: file descriptor open for writing for the output file
+ * load_addr: code load address (could be zero, just used for buildid)
+ * sym: function name (for native code - used as the symbol)
+ * code: the native code
+ * csize: the code size in bytes
+ */
+int
+jit_write_elf(int fd, uint64_t load_addr, const char *sym,
+ const void *code, int csize)
+{
+ Elf *e;
+ Elf_Data *d;
+ Elf_Scn *scn;
+ Elf_Ehdr *ehdr;
+ Elf_Shdr *shdr;
+ char *strsym = NULL;
+ int symlen;
+ int retval = -1;
+
+ if (elf_version(EV_CURRENT) == EV_NONE) {
+ warnx("ELF initialization failed");
+ return -1;
+ }
+
+ e = elf_begin(fd, ELF_C_WRITE, NULL);
+ if (!e) {
+ warnx("elf_begin failed");
+ goto error;
+ }
+
+ /*
+ * setup ELF header
+ */
+ ehdr = elf_newehdr(e);
+ if (!ehdr) {
+ warnx("cannot get ehdr");
+ goto error;
+ }
+
+ ehdr->e_ident[EI_DATA] = GEN_ELF_ENDIAN;
+ ehdr->e_ident[EI_CLASS] = GEN_ELF_CLASS;
+ ehdr->e_machine = GEN_ELF_ARCH;
+ ehdr->e_type = ET_DYN;
+ ehdr->e_entry = GEN_ELF_TEXT_OFFSET;
+ ehdr->e_version = EV_CURRENT;
+ ehdr->e_shstrndx= 2; /* shdr index for section name */
+
+ /*
+ * setup text section
+ */
+ scn = elf_newscn(e);
+ if (!scn) {
+ warnx("cannot create section");
+ goto error;
+ }
+
+ d = elf_newdata(scn);
+ if (!d) {
+ warnx("cannot get new data");
+ goto error;
+ }
+
+ d->d_align = 16;
+ d->d_off = 0LL;
+ d->d_buf = (void *)code;
+ d->d_type = ELF_T_BYTE;
+ d->d_size = csize;
+ d->d_version = EV_CURRENT;
+
+ shdr = elf_getshdr(scn);
+ if (!shdr) {
+ warnx("cannot get section header");
+ goto error;
+ }
+
+ shdr->sh_name = 1;
+ shdr->sh_type = SHT_PROGBITS;
+ shdr->sh_addr = GEN_ELF_TEXT_OFFSET;
+ shdr->sh_flags = SHF_EXECINSTR | SHF_ALLOC;
+ shdr->sh_entsize = 0;
+
+ /*
+ * setup section headers string table
+ */
+ scn = elf_newscn(e);
+ if (!scn) {
+ warnx("cannot create section");
+ goto error;
+ }
+
+ d = elf_newdata(scn);
+ if (!d) {
+ warnx("cannot get new data");
+ goto error;
+ }
+
+ d->d_align = 1;
+ d->d_off = 0LL;
+ d->d_buf = shd_string_table;
+ d->d_type = ELF_T_BYTE;
+ d->d_size = sizeof(shd_string_table);
+ d->d_version = EV_CURRENT;
+
+ shdr = elf_getshdr(scn);
+ if (!shdr) {
+ warnx("cannot get section header");
+ goto error;
+ }
+
+ shdr->sh_name = 7; /* offset of '.shstrtab' in shd_string_table */
+ shdr->sh_type = SHT_STRTAB;
+ shdr->sh_flags = 0;
+ shdr->sh_entsize = 0;
+
+ /*
+ * setup symtab section
+ */
+ symtab[1].st_size = csize;
+ symtab[1].st_value = GEN_ELF_TEXT_OFFSET;
+
+ scn = elf_newscn(e);
+ if (!scn) {
+ warnx("cannot create section");
+ goto error;
+ }
+
+ d = elf_newdata(scn);
+ if (!d) {
+ warnx("cannot get new data");
+ goto error;
+ }
+
+ d->d_align = 8;
+ d->d_off = 0LL;
+ d->d_buf = symtab;
+ d->d_type = ELF_T_SYM;
+ d->d_size = sizeof(symtab);
+ d->d_version = EV_CURRENT;
+
+ shdr = elf_getshdr(scn);
+ if (!shdr) {
+ warnx("cannot get section header");
+ goto error;
+ }
+
+ shdr->sh_name = 17; /* offset of '.symtab' in shd_string_table */
+ shdr->sh_type = SHT_SYMTAB;
+ shdr->sh_flags = 0;
+ shdr->sh_entsize = sizeof(Elf_Sym);
+ shdr->sh_link = 4; /* index of .strtab section */
+
+ /*
+ * setup symbols string table
+ * 2 = 1 for 0 in 1st entry, 1 for the 0 at end of symbol for 2nd entry
+ */
+ symlen = 2 + strlen(sym);
+ strsym = calloc(1, symlen);
+ if (!strsym) {
+ warnx("cannot allocate strsym");
+ goto error;
+ }
+ strcpy(strsym + 1, sym);
+
+ scn = elf_newscn(e);
+ if (!scn) {
+ warnx("cannot create section");
+ goto error;
+ }
+
+ d = elf_newdata(scn);
+ if (!d) {
+ warnx("cannot get new data");
+ goto error;
+ }
+
+ d->d_align = 1;
+ d->d_off = 0LL;
+ d->d_buf = strsym;
+ d->d_type = ELF_T_BYTE;
+ d->d_size = symlen;
+ d->d_version = EV_CURRENT;
+
+ shdr = elf_getshdr(scn);
+ if (!shdr) {
+ warnx("cannot get section header");
+ goto error;
+ }
+
+ shdr->sh_name = 25; /* offset in shd_string_table */
+ shdr->sh_type = SHT_STRTAB;
+ shdr->sh_flags = 0;
+ shdr->sh_entsize = 0;
+
+ /*
+ * setup build-id section
+ */
+ scn = elf_newscn(e);
+ if (!scn) {
+ warnx("cannot create section");
+ goto error;
+ }
+
+ d = elf_newdata(scn);
+ if (!d) {
+ warnx("cannot get new data");
+ goto error;
+ }
+
+ /*
+ * build-id generation
+ */
+ gen_build_id(&bnote, load_addr, code, csize);
+ bnote.desc.namesz = sizeof(bnote.name); /* must include 0 termination */
+ bnote.desc.descsz = sizeof(bnote.build_id);
+ bnote.desc.type = NT_GNU_BUILD_ID;
+ strcpy(bnote.name, "GNU");
+
+ d->d_align = 4;
+ d->d_off = 0LL;
+ d->d_buf = &bnote;
+ d->d_type = ELF_T_BYTE;
+ d->d_size = sizeof(bnote);
+ d->d_version = EV_CURRENT;
+
+ shdr = elf_getshdr(scn);
+ if (!shdr) {
+ warnx("cannot get section header");
+ goto error;
+ }
+
+ shdr->sh_name = 33; /* offset in shd_string_table */
+ shdr->sh_type = SHT_NOTE;
+ shdr->sh_addr = 0x0;
+ shdr->sh_flags = SHF_ALLOC;
+ shdr->sh_size = sizeof(bnote);
+ shdr->sh_entsize = 0;
+
+ 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;
+}
+
+#ifndef JVMTI
+
+static unsigned char x86_code[] = {
+ 0xBB, 0x2A, 0x00, 0x00, 0x00, /* movl $42, %ebx */
+ 0xB8, 0x01, 0x00, 0x00, 0x00, /* movl $1, %eax */
+ 0xCD, 0x80 /* int $0x80 */
+};
+
+static struct options options;
+
+int main(int argc, char **argv)
+{
+ int c, fd, ret;
+
+ while ((c = getopt(argc, argv, "o:h")) != -1) {
+ switch (c) {
+ case 'o':
+ options.output = optarg;
+ break;
+ case 'h':
+ printf("Usage: genelf -o output_file [-h]\n");
+ return 0;
+ default:
+ errx(1, "unknown option");
+ }
+ }
+
+ fd = open(options.output, O_CREAT|O_TRUNC|O_RDWR, 0666);
+ if (fd == -1)
+ err(1, "cannot create file %s", options.output);
+
+ ret = jit_write_elf(fd, "main", x86_code, sizeof(x86_code));
+ close(fd);
+
+ if (ret != 0)
+ unlink(options.output);
+
+ return ret;
+}
+#endif