diff options
Diffstat (limited to '')
| -rw-r--r-- | tools/perf/util/genelf.c | 554 |
1 files changed, 554 insertions, 0 deletions
diff --git a/tools/perf/util/genelf.c b/tools/perf/util/genelf.c new file mode 100644 index 000000000..aafbe54fd --- /dev/null +++ b/tools/perf/util/genelf.c @@ -0,0 +1,554 @@ +/* + * 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> +#ifdef HAVE_DWARF_SUPPORT +#include <dwarf.h> +#endif + +#include "perf.h" +#include "genelf.h" +#include "../util/jitdump.h" + +#ifndef NT_GNU_BUILD_ID +#define NT_GNU_BUILD_ID 3 +#endif + +#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 */ + '.', 'e', 'h', '_', 'f', 'r', 'a', 'm', 'e', '_', 'h', 'd', 'r', 0, /* 90 */ + '.', 'e', 'h', '_', 'f', 'r', 'a', 'm', 'e', 0, /* 104 */ +}; + +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 buildid"); + + 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 + +static int +jit_add_eh_frame_info(Elf *e, void* unwinding, uint64_t unwinding_header_size, + uint64_t unwinding_size, uint64_t base_offset) +{ + Elf_Data *d; + Elf_Scn *scn; + Elf_Shdr *shdr; + uint64_t unwinding_table_size = unwinding_size - unwinding_header_size; + + /* + * setup eh_frame section + */ + scn = elf_newscn(e); + if (!scn) { + warnx("cannot create section"); + return -1; + } + + d = elf_newdata(scn); + if (!d) { + warnx("cannot get new data"); + return -1; + } + + d->d_align = 8; + d->d_off = 0LL; + d->d_buf = unwinding; + d->d_type = ELF_T_BYTE; + d->d_size = unwinding_table_size; + d->d_version = EV_CURRENT; + + shdr = elf_getshdr(scn); + if (!shdr) { + warnx("cannot get section header"); + return -1; + } + + shdr->sh_name = 104; + shdr->sh_type = SHT_PROGBITS; + shdr->sh_addr = base_offset; + shdr->sh_flags = SHF_ALLOC; + shdr->sh_entsize = 0; + + /* + * setup eh_frame_hdr section + */ + scn = elf_newscn(e); + if (!scn) { + warnx("cannot create section"); + return -1; + } + + d = elf_newdata(scn); + if (!d) { + warnx("cannot get new data"); + return -1; + } + + d->d_align = 4; + d->d_off = 0LL; + d->d_buf = unwinding + unwinding_table_size; + d->d_type = ELF_T_BYTE; + d->d_size = unwinding_header_size; + d->d_version = EV_CURRENT; + + shdr = elf_getshdr(scn); + if (!shdr) { + warnx("cannot get section header"); + return -1; + } + + shdr->sh_name = 90; + shdr->sh_type = SHT_PROGBITS; + shdr->sh_addr = base_offset + unwinding_table_size; + shdr->sh_flags = SHF_ALLOC; + shdr->sh_entsize = 0; + + return 0; +} + +/* + * 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, + void *debug __maybe_unused, int nr_debug_entries __maybe_unused, + void *unwinding, uint64_t unwinding_header_size, uint64_t unwinding_size) +{ + Elf *e; + Elf_Data *d; + Elf_Scn *scn; + Elf_Ehdr *ehdr; + Elf_Shdr *shdr; + uint64_t eh_frame_base_offset; + 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= unwinding ? 4 : 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 .eh_frame_hdr and .eh_frame + */ + if (unwinding) { + eh_frame_base_offset = ALIGN_8(GEN_ELF_TEXT_OFFSET + csize); + retval = jit_add_eh_frame_info(e, unwinding, + unwinding_header_size, unwinding_size, + eh_frame_base_offset); + if (retval) + goto error; + } + + /* + * 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 = unwinding ? 6 : 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; + +#ifdef HAVE_DWARF_SUPPORT + if (debug && nr_debug_entries) { + retval = jit_add_debug_info(e, load_addr, debug, nr_debug_entries); + if (retval) + goto error; + } else +#endif + { + 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 |