/*
* recordmcount.c: construct a table of the locations of calls to 'mcount'
* so that ftrace can find them quickly.
* Copyright 2009 John F. Reiser <jreiser@BitWagon.com>. All rights reserved.
* Licensed under the GNU General Public License, version 2 (GPLv2).
*
* Restructured to fit Linux format, as well as other updates:
* Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc.
*/
/*
* Strategy: alter the .o file in-place.
*
* Append a new STRTAB that has the new section names, followed by a new array
* ElfXX_Shdr[] that has the new section headers, followed by the section
* contents for __mcount_loc and its relocations. The old shstrtab strings,
* and the old ElfXX_Shdr[] array, remain as "garbage" (commonly, a couple
* kilobytes.) Subsequent processing by /bin/ld (or the kernel module loader)
* will ignore the garbage regions, because they are not designated by the
* new .e_shoff nor the new ElfXX_Shdr[]. [In order to remove the garbage,
* then use "ld -r" to create a new file that omits the garbage.]
*/
#include <sys/types.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <elf.h>
#include <fcntl.h>
#include <setjmp.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
static int fd_map; /* File descriptor for file being modified. */
static int mmap_failed; /* Boolean flag. */
static void *ehdr_curr; /* current ElfXX_Ehdr * for resource cleanup */
static char gpfx; /* prefix for global symbol name (sometimes '_') */
static struct stat sb; /* Remember .st_size, etc. */
static jmp_buf jmpenv; /* setjmp/longjmp per-file error escape */
/* setjmp() return values */
enum {
SJ_SETJMP = 0, /* hardwired first return */
SJ_FAIL,
SJ_SUCCEED
};
/* Per-file resource cleanup when multiple files. */
static void
cleanup(void)
{
if (!mmap_failed)
munmap(ehdr_curr, sb.st_size);
else
free(ehdr_curr);
close(fd_map);
}
static void __attribute__((noreturn))
fail_file(void)
{
cleanup();
longjmp(jmpenv, SJ_FAIL);
}
static void __attribute__((noreturn))
succeed_file(void)
{
cleanup();
longjmp(jmpenv, SJ_SUCCEED);
}
/* ulseek, uread, ...: Check return value for errors. */
static off_t
ulseek(int const fd, off_t const offset, int const whence)
{
off_t const w = lseek(fd, offset, whence);
if ((off_t)-1 == w) {
perror("lseek");
fail_file();
}
return w;
}
static size_t
uread(int const fd, void *const buf, size_t const count)
{
size_t const n = read(fd, buf, count);
if (n != count) {
perror("read");
fail_file();
}
return n;
}
static size_t
uwrite(int const fd, void const *const buf, size_t const count)
{
size_t const n = write(fd, buf, count);
if (n != count) {
perror("write");
fail_file();
}
return n;
}
static void *
umalloc(size_t size)
{
void *const addr = malloc(size);
if (0 == addr) {
fprintf(stderr, "malloc failed: %zu bytes\n", size);
fail_file();
}
return addr;
}
/*
* Get the whole file as a programming convenience in order to avoid
* malloc+lseek+read+free of many pieces. If successful, then mmap
* avoids copying unused pieces; else just read the whole file.
* Open for both read and write; new info will be appended to the file.
* Use MAP_PRIVATE so that a few changes to the in-memory ElfXX_Ehdr
* do not propagate to the file until an explicit overwrite at the last.
* This preserves most aspects of consistency (all except .st_size)
* for simultaneous readers of the file while we are appending to it.
* However, multiple writers still are bad. We choose not to use
* locking because it is expensive and the use case of kernel build
* makes multiple writers unlikely.
*/
static void *mmap_file(char const *fname)
{
void *addr;
fd_map = open(fname, O_RDWR);
if (0 > fd_map || 0 > fstat(fd_map, &sb)) {
perror(fname);
fail_file();
}
if (!S_ISREG(sb.st_mode)) {
fprintf(stderr, "not a regular file: %s\n", fname);
fail_file();
}
addr = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_PRIVATE,
fd_map, 0);
mmap_failed = 0;
if (MAP_FAILED == addr) {
mmap_failed = 1;
addr = umalloc(sb.st_size);
uread(fd_map, addr, sb.st_size);
}
return addr;
}
/* w8rev, w8nat, ...: Handle endianness. */
static uint64_t w8rev(uint64_t const x)
{
return ((0xff & (x >> (0 * 8))) << (7 * 8))
| ((0xff & (x >> (1 * 8))) << (6 * 8))
| ((0xff & (x >> (2 * 8))) << (5 * 8))
| ((0xff & (x >> (3 * 8))) << (4 * 8))
| ((0xff & (x >> (4 * 8))) << (3 * 8))
| ((0xff & (x >> (5 * 8))) << (2 * 8))
| ((0xff & (x >> (6 * 8))) << (1 * 8))
| ((0xff & (x >> (7 * 8))) << (0 * 8));
}
static uint32_t w4rev(uint32_t const x)
{
return ((0xff & (x >> (0 * 8))) << (3 * 8))
| ((0xff & (x >> (1 * 8))) << (2 * 8))
| ((0xff & (x >> (2 * 8))) << (1 * 8))
| ((0xff & (x >> (3 * 8))) << (0 * 8));
}
static uint32_t w2rev(uint16_t const x)
{
return ((0xff & (x >> (0 * 8))) << (1 * 8))
| ((0xff & (x >> (1 * 8))) << (0 * 8));
}
static uint64_t w8nat(uint64_t const x)
{
return x;
}
static uint32_t w4nat(uint32_t const x)
{
return x;
}
static uint32_t w2nat(uint16_t const x)
{
return x;
}
static uint64_t (*w8)(uint64_t);
static uint32_t (*w)(uint32_t);
static uint32_t (*w2)(uint16_t);
/* Names of the sections that could contain calls to mcount. */
static int
is_mcounted_section_name(char const *const txtname)
{
return 0 == strcmp(".text", txtname) ||
0 == strcmp(".sched.text", txtname) ||
0 == strcmp(".spinlock.text", txtname) ||
0 == strcmp(".irqentry.text", txtname) ||
0 == strcmp(".text.unlikely", txtname);
}
/* Append the new shstrtab, Elf32_Shdr[], __mcount_loc and its relocations. */
static void append32(Elf32_Ehdr *const ehdr,
Elf32_Shdr *const shstr,
uint32_t const *const mloc0,
uint32_t const *const mlocp,
Elf32_Rel const *const mrel0,
Elf32_Rel const *const mrelp,
unsigned int const rel_entsize,
unsigned int const symsec_sh_link)
{
/* Begin constructing output file */
Elf32_Shdr mcsec;
char const *mc_name = (sizeof(Elf32_Rela) == rel_entsize)
? ".rela__mcount_loc"
: ".rel__mcount_loc";
unsigned const old_shnum = w2(ehdr->e_shnum);
uint32_t const old_shoff = w(ehdr->e_shoff);
uint32_t const old_shstr_sh_size = w(shstr->sh_size);
uint32_t const old_shstr_sh_offset = w(shstr->sh_offset);
uint32_t t = 1 + strlen(mc_name) + w(shstr->sh_size);
uint32_t new_e_shoff;
shstr->sh_size = w(t);
shstr->sh_offset = w(sb.st_size);
t += sb.st_size;
t += (3u & -t); /* 4-byte align */
new_e_shoff = t;
/* body for new shstrtab */
ulseek(fd_map, sb.st_size, SEEK_SET);
uwrite(fd_map, old_shstr_sh_offset + (void *)ehdr, old_shstr_sh_size);
uwrite(fd_map, mc_name, 1 + strlen(mc_name));
/* old(modified) Elf32_Shdr table, 4-byte aligned */
ulseek(fd_map, t, SEEK_SET);
t += sizeof(Elf32_Shdr) * old_shnum;
uwrite(fd_map, old_shoff + (void *)ehdr,
sizeof(Elf32_Shdr) * old_shnum);
/* new sections __mcount_loc and .rel__mcount_loc */
t += 2*sizeof(mcsec);
mcsec.sh_name = w((sizeof(Elf32_Rela) == rel_entsize) + strlen(".rel")
+ old_shstr_sh_size);
mcsec.sh_type = w(SHT_PROGBITS);
mcsec.sh_flags = w(SHF_ALLOC);
mcsec.sh_addr = 0;
mcsec.sh_offset = w(t);
mcsec.sh_size = w((void *)mlocp - (void *)mloc0);
mcsec.sh_link = 0;
mcsec.sh_info = 0;
mcsec.sh_addralign = w(4);
mcsec.sh_entsize = w(4);
uwrite(fd_map, &mcsec, sizeof(mcsec));
mcsec.sh_name = w(old_shstr_sh_size);
mcsec.sh_type = (sizeof(Elf32_Rela) == rel_entsize)
? w(SHT_RELA)
: w(SHT_REL);
mcsec.sh_flags = 0;
mcsec.sh_addr = 0;
mcsec.sh_offset = w((void *)mlocp - (void *)mloc0 + t);
mcsec.sh_size = w((void *)mrelp - (void *)mrel0);
mcsec.sh_link = w(symsec_sh_link);
mcsec.sh_info = w(old_shnum);
mcsec.sh_addralign = w(4);
mcsec.sh_entsize = w(rel_entsize);
uwrite(fd_map, &mcsec, sizeof(mcsec));
uwrite(fd_map, mloc0, (void *)mlocp - (void *)mloc0);
uwrite(fd_map, mrel0, (void *)mrelp - (void *)mrel0);
ehdr->e_shoff = w(new_e_shoff);
ehdr->e_shnum = w2(2 + w2(ehdr->e_shnum)); /* {.rel,}__mcount_loc */
ulseek(fd_map, 0, SEEK_SET);
uwrite(fd_map, ehdr, sizeof(*ehdr));
}
/*
* append64 and append32 (and other analogous pairs) could be templated
* using C++, but the complexity is high. (For an example, look at p_elf.h
* in the source for UPX, http://upx.sourceforge.net) So: remember to make
* the corresponding change in the routine for the other size.
*/
static void append64(Elf64_Ehdr *const ehdr,
Elf64_Shdr *const shstr,
uint64_t const *const mloc0,
uint64_t const *const mlocp,
Elf64_Rel const *const mrel0,
Elf64_Rel const *const mrelp,
unsigned int const rel_entsize,
unsigned int const symsec_sh_link)
{
/* Begin constructing output file */
Elf64_Shdr mcsec;
char const *mc_name = (sizeof(Elf64_Rela) == rel_entsize)
? ".rela__mcount_loc"
: ".rel__mcount_loc";
unsigned const old_shnum = w2(ehdr->e_shnum);
uint64_t const old_shoff = w8(ehdr->e_shoff);
uint64_t const old_shstr_sh_size = w8(shstr->sh_size);
uint64_t const old_shstr_sh_offset = w8(shstr->sh_offset);
uint64_t t = 1 + strlen(mc_name) + w8(shstr->sh_size);
uint64_t new_e_shoff;
shstr->sh_size = w8(t);
shstr->sh_offset = w8(sb.st_size);
t += sb.st_size;
t += (7u & -t); /* 8-byte align */
new_e_shoff = t;
/* body for new shstrtab */
ulseek(fd_map, sb.st_size, SEEK_SET);
uwrite(fd_map, old_shstr_sh_offset + (void *)ehdr, old_shstr_sh_size);
uwrite(fd_map, mc_name, 1 + strlen(mc_name));
/* old(modified) Elf64_Shdr table, 8-byte aligned */
ulseek(fd_map, t, SEEK_SET);
t += sizeof(Elf64_Shdr) * old_shnum;
uwrite(fd_map, old_shoff + (void *)ehdr,
sizeof(Elf64_Shdr) * old_shnum);
/* new sections __mcount_loc and .rel__mcount_loc */
t += 2*sizeof(mcsec);
mcsec.sh_name = w((sizeof(Elf64_Rela) == rel_entsize) + strlen(".rel")
+ old_shstr_sh_size);
mcsec.sh_type = w(SHT_PROGBITS);
mcsec.sh_flags = w8(SHF_ALLOC);
mcsec.sh_addr = 0;
mcsec.sh_offset = w8(t);
mcsec.sh_size = w8((void *)mlocp - (void *)mloc0);
mcsec.sh_link = 0;
mcsec.sh_info = 0;
mcsec.sh_addralign = w8(8);
mcsec.sh_entsize = w8(8);
uwrite(fd_map, &mcsec, sizeof(mcsec));
mcsec.sh_name = w(old_shstr_sh_size);
mcsec.sh_type = (sizeof(Elf64_Rela) == rel_entsize)
? w(SHT_RELA)
: w(SHT_REL);
mcsec.sh_flags = 0;
mcsec.sh_addr = 0;
mcsec.sh_offset = w8((void *)mlocp - (void *)mloc0 + t);
mcsec.sh_size = w8((void *)mrelp - (void *)mrel0);
mcsec.sh_link = w(symsec_sh_link);
mcsec.sh_info = w(old_shnum);
mcsec.sh_addralign = w8(8);
mcsec.sh_entsize = w8(rel_entsize);
uwrite(fd_map, &mcsec, sizeof(mcsec));
uwrite(fd_map, mloc0, (void *)mlocp - (void *)mloc0);
uwrite(fd_map, mrel0, (void *)mrelp - (void *)mrel0);
ehdr->e_shoff = w8(new_e_shoff);
ehdr->e_shnum = w2(2 + w2(ehdr->e_shnum)); /* {.rel,}__mcount_loc */
ulseek(fd_map, 0, SEEK_SET);
uwrite(fd_map, ehdr, sizeof(*ehdr));
}
/*
* Look at the relocations in order to find the calls to mcount.
* Accumulate the section offsets that are found, and their relocation info,
* onto the end of the existing arrays.
*/
static uint32_t *sift32_rel_mcount(uint32_t *mlocp,
unsigned const offbase,
Elf32_Rel **const mrelpp,
Elf32_Shdr const *const relhdr,
Elf32_Ehdr const *const ehdr,
unsigned const recsym,
uint32_t const recval,
unsigned const reltype)
{
uint32_t *const mloc0 = mlocp;
Elf32_Rel *mrelp = *mrelpp;
Elf32_Shdr *const shdr0 = (Elf32_Shdr *)(w(ehdr->e_shoff)
+ (void *)ehdr);
unsigned const symsec_sh_link = w(relhdr->sh_link);
Elf32_Shdr const *const symsec = &shdr0[symsec_sh_link];
Elf32_Sym const *const sym0 = (Elf32_Sym const *)(w(symsec->sh_offset)
+ (void *)ehdr);
Elf32_Shdr const *const strsec = &shdr0[w(symsec->sh_link)];
char const *const str0 = (char const *)(w(strsec->sh_offset)
+ (void *)ehdr);
Elf32_Rel const *const rel0 = (Elf32_Rel const *)(w(relhdr->sh_offset)
+ (void *)ehdr);
unsigned rel_entsize = w(relhdr->sh_entsize);
unsigned const nrel = w(relhdr->sh_size) / rel_entsize;
Elf32_Rel const *relp = rel0;
unsigned mcountsym = 0;
unsigned t;
for (t = nrel; t; --t) {
if (!mcountsym) {
Elf32_Sym const *const symp =
&sym0[ELF32_R_SYM(w(relp->r_info))];
if (0 == strcmp((('_' == gpfx) ? "_mcount" : "mcount"),
&str0[w(symp->st_name)]))
mcountsym = ELF32_R_SYM(w(relp->r_info));
}
if (mcountsym == ELF32_R_SYM(w(relp->r_info))) {
uint32_t const addend = w(w(relp->r_offset) - recval);
mrelp->r_offset = w(offbase
+ ((void *)mlocp - (void *)mloc0));
mrelp->r_info = w(ELF32_R_INFO(recsym, reltype));
if (sizeof(Elf32_Rela) == rel_entsize) {
((Elf32_Rela *)mrelp)->r_addend = addend;
*mlocp++ = 0;
} else
*mlocp++ = addend;
mrelp = (Elf32_Rel *)(rel_entsize + (void *)mrelp);
}
relp = (Elf32_Rel const *)(rel_entsize + (void *)relp);
}
*mrelpp = mrelp;
return mlocp;
}
static uint64_t *sift64_rel_mcount(uint64_t *mlocp,
unsigned const offbase,
Elf64_Rel **const mrelpp,
Elf64_Shdr const *const relhdr,
Elf64_Ehdr const *const ehdr,
unsigned const recsym,
uint64_t const recval,
unsigned const reltype)
{
uint64_t *const mloc0 = mlocp;
Elf64_Rel *mrelp = *mrelpp;
Elf64_Shdr *const shdr0 = (Elf64_Shdr *)(w8(ehdr->e_shoff)
+ (void *)ehdr);
unsigned const symsec_sh_link = w(relhdr->sh_link);
Elf64_Shdr const *const symsec = &shdr0[symsec_sh_link];
Elf64_Sym const *const sym0 = (Elf64_Sym const *)(w8(symsec->sh_offset)
+ (void *)ehdr);
Elf64_Shdr const *const strsec = &shdr0[w(symsec->sh_link)];
char const *const str0 = (char const *)(w8(strsec->sh_offset)
+ (void *)ehdr);
Elf64_Rel const *const rel0 = (Elf64_Rel const *)(w8(relhdr->sh_offset)
+ (void *)ehdr);
unsigned rel_entsize = w8(relhdr->sh_entsize);
unsigned const nrel = w8(relhdr->sh_size) / rel_entsize;
Elf64_Rel const *relp = rel0;
unsigned mcountsym = 0;
unsigned t;
for (t = nrel; 0 != t; --t) {
if (!mcountsym) {
Elf64_Sym const *const symp =
&sym0[ELF64_R_SYM(w8(relp->r_info))];
char const *symname = &str0[w(symp->st_name)];
if ('.' == symname[0])
++symname; /* ppc64 hack */
if (0 == strcmp((('_' == gpfx) ? "_mcount" : "mcount"),
symname))
mcountsym = ELF64_R_SYM(w8(relp->r_info));
}
if (mcountsym == ELF64_R_SYM(w8(relp->r_info))) {
uint64_t const addend = w8(w8(relp->r_offset) - recval);
mrelp->r_offset = w8(offbase
+ ((void *)mlocp - (void *)mloc0));
mrelp->r_info = w8(ELF64_R_INFO(recsym, reltype));
if (sizeof(Elf64_Rela) == rel_entsize) {
((Elf64_Rela *)mrelp)->r_addend = addend;
*mlocp++ = 0;
} else
*mlocp++ = addend;
mrelp = (Elf64_Rel *)(rel_entsize + (void *)mrelp);
}
relp = (Elf64_Rel const *)(rel_entsize + (void *)relp);
}
*mrelpp = mrelp;
return mlocp;
}
/*
* Find a symbol in the given section, to be used as the base for relocating
* the table of offsets of calls to mcount. A local or global symbol suffices,
* but avoid a Weak symbol because it may be overridden; the change in value
* would invalidate the relocations of the offsets of the calls to mcount.
* Often the found symbol will be the unnamed local symbol generated by
* GNU 'as' for the start of each section. For example:
* Num: Value Size Type Bind Vis Ndx Name
* 2: 00000000 0 SECTION LOCAL DEFAULT 1
*/
static unsigned find32_secsym_ndx(unsigned const txtndx,
char const *const txtname,
uint32_t *const recvalp,
Elf32_Shdr const *const symhdr,
Elf32_Ehdr const *const ehdr)
{
Elf32_Sym const *const sym0 = (Elf32_Sym const *)(w(symhdr->sh_offset)
+ (void *)ehdr);
unsigned const nsym = w(symhdr->sh_size) / w(symhdr->sh_entsize);
Elf32_Sym const *symp;
unsigned t;
for (symp = sym0, t = nsym; t; --t, ++symp) {
unsigned int const st_bind = ELF32_ST_BIND(symp->st_info);
if (txtndx == w2(symp->st_shndx)
/* avoid STB_WEAK */
&& (STB_LOCAL == st_bind || STB_GLOBAL == st_bind)) {
*recvalp = w(symp->st_value);
return symp - sym0;
}
}
fprintf(stderr, "Cannot find symbol for section %d: %s.\n",
txtndx, txtname);
fail_file();
}
static unsigned find64_secsym_ndx(unsigned const txtndx,
char const *const txtname,
uint64_t *const recvalp,
Elf64_Shdr const *const symhdr,
Elf64_Ehdr const *const ehdr)
{
Elf64_Sym const *const sym0 = (Elf64_Sym const *)(w8(symhdr->sh_offset)
+ (void *)ehdr);
unsigned const nsym = w8(symhdr->sh_size) / w8(symhdr->sh_entsize);
Elf64_Sym const *symp;
unsigned t;
for (symp = sym0, t = nsym; t; --t, ++symp) {
unsigned int const st_bind = ELF64_ST_BIND(symp->st_info);
if (txtndx == w2(symp->st_shndx)
/* avoid STB_WEAK */
&& (STB_LOCAL == st_bind || STB_GLOBAL == st_bind)) {
*recvalp = w8(symp->st_value);
return symp - sym0;
}
}
fprintf(stderr, "Cannot find symbol for section %d: %s.\n",
txtndx, txtname);
fail_file();
}
/*
* Evade ISO C restriction: no declaration after statement in
* has32_rel_mcount.
*/
static char const *
__has32_rel_mcount(Elf32_Shdr const *const relhdr, /* is SHT_REL or SHT_RELA */
Elf32_Shdr const *const shdr0,
char const *const shstrtab,
char const *const fname)
{
/* .sh_info depends on .sh_type == SHT_REL[,A] */
Elf32_Shdr const *const txthdr = &shdr0[w(relhdr->sh_info)];
char const *const txtname = &shstrtab[w(txthdr->sh_name)];
if (0 == strcmp("__mcount_loc", txtname)) {
fprintf(stderr, "warning: __mcount_loc already exists: %s\n",
fname);
succeed_file();
}
if (SHT_PROGBITS != w(txthdr->sh_type) ||
!is_mcounted_section_name(txtname))
return NULL;
return txtname;
}
static char const *has32_rel_mcount(Elf32_Shdr const *const relhdr,
Elf32_Shdr const *const shdr0,
char const *const shstrtab,
char const *const fname)
{
if (SHT_REL != w(relhdr->sh_type) && SHT_RELA != w(relhdr->sh_type))
return NULL;
return __has32_rel_mcount(relhdr, shdr0, shstrtab, fname);
}
static char const *__has64_rel_mcount(Elf64_Shdr const *const relhdr,
Elf64_Shdr const *const shdr0,
char const *const shstrtab,
char const *const fname)
{
/* .sh_info depends on .sh_type == SHT_REL[,A] */
Elf64_Shdr const *const txthdr = &shdr0[w(relhdr->sh_info)];
char const *const txtname = &shstrtab[w(txthdr->sh_name)];
if (0 == strcmp("__mcount_loc", txtname)) {
fprintf(stderr, "warning: __mcount_loc already exists: %s\n",
fname);
succeed_file();
}
if (SHT_PROGBITS != w(txthdr->sh_type) ||
!is_mcounted_section_name(txtname))
return NULL;
return txtname;
}
static char const *has64_rel_mcount(Elf64_Shdr const *const relhdr,
Elf64_Shdr const *const shdr0,
char const *const shstrtab,
char const *const fname)
{
if (SHT_REL != w(relhdr->sh_type) && SHT_RELA != w(relhdr->sh_type))
return NULL;
return __has64_rel_mcount(relhdr, shdr0, shstrtab, fname);
}
static unsigned tot32_relsize(Elf32_Shdr const *const shdr0,
unsigned nhdr,
const char *const shstrtab,
const char *const fname)
{
unsigned totrelsz = 0;
Elf32_Shdr const *shdrp = shdr0;
for (; 0 != nhdr; --nhdr, ++shdrp) {
if (has32_rel_mcount(shdrp, shdr0, shstrtab, fname))
totrelsz += w(shdrp->sh_size);
}
return totrelsz;
}
static unsigned tot64_relsize(Elf64_Shdr const *const shdr0,
unsigned nhdr,
const char *const shstrtab,
const char *const fname)
{
unsigned totrelsz = 0;
Elf64_Shdr const *shdrp = shdr0;
for (; nhdr; --nhdr, ++shdrp) {
if (has64_rel_mcount(shdrp, shdr0, shstrtab, fname))
totrelsz += w8(shdrp->sh_size);
}
return totrelsz;
}
/* Overall supervision for Elf32 ET_REL file. */
static void
do32(Elf32_Ehdr *const ehdr, char const *const fname, unsigned const reltype)
{
Elf32_Shdr *const shdr0 = (Elf32_Shdr *)(w(ehdr->e_shoff)
+ (void *)ehdr);
unsigned const nhdr = w2(ehdr->e_shnum);
Elf32_Shdr *const shstr = &shdr0[w2(ehdr->e_shstrndx)];
char const *const shstrtab = (char const *)(w(shstr->sh_offset)
+ (void *)ehdr);
Elf32_Shdr const *relhdr;
unsigned k;
/* Upper bound on space: assume all relevant relocs are for mcount. */
unsigned const totrelsz = tot32_relsize(shdr0, nhdr, shstrtab, fname);
Elf32_Rel *const mrel0 = umalloc(totrelsz);
Elf32_Rel * mrelp = mrel0;
/* 2*sizeof(address) <= sizeof(Elf32_Rel) */
uint32_t *const mloc0 = umalloc(totrelsz>>1);
uint32_t * mlocp = mloc0;
unsigned rel_entsize = 0;
unsigned symsec_sh_link = 0;
for (relhdr = shdr0, k = nhdr; k; --k, ++relhdr) {
char const *const txtname = has32_rel_mcount(relhdr, shdr0,
shstrtab, fname);
if (txtname) {
uint32_t recval = 0;
unsigned const recsym = find32_secsym_ndx(
w(relhdr->sh_info), txtname, &recval,
&shdr0[symsec_sh_link = w(relhdr->sh_link)],
ehdr);
rel_entsize = w(relhdr->sh_entsize);
mlocp = sift32_rel_mcount(mlocp,
(void *)mlocp - (void *)mloc0, &mrelp,
relhdr, ehdr, recsym, recval, reltype);
}
}
if (mloc0 != mlocp) {
append32(ehdr, shstr, mloc0, mlocp, mrel0, mrelp,
rel_entsize, symsec_sh_link);
}
free(mrel0);
free(mloc0);
}
static void
do64(Elf64_Ehdr *const ehdr, char const *const fname, unsigned const reltype)
{
Elf64_Shdr *const shdr0 = (Elf64_Shdr *)(w8(ehdr->e_shoff)
+ (void *)ehdr);
unsigned const nhdr = w2(ehdr->e_shnum);
Elf64_Shdr *const shstr = &shdr0[w2(ehdr->e_shstrndx)];
char const *const shstrtab = (char const *)(w8(shstr->sh_offset)
+ (void *)ehdr);
Elf64_Shdr const *relhdr;
unsigned k;
/* Upper bound on space: assume all relevant relocs are for mcount. */
unsigned const totrelsz = tot64_relsize(shdr0, nhdr, shstrtab, fname);
Elf64_Rel *const mrel0 = umalloc(totrelsz);
Elf64_Rel * mrelp = mrel0;
/* 2*sizeof(address) <= sizeof(Elf64_Rel) */
uint64_t *const mloc0 = umalloc(totrelsz>>1);
uint64_t * mlocp = mloc0;
unsigned rel_entsize = 0;
unsigned symsec_sh_link = 0;
for ((relhdr = shdr0), k = nhdr; k; --k, ++relhdr) {
char const *const txtname = has64_rel_mcount(relhdr, shdr0,
shstrtab, fname);
if (txtname) {
uint64_t recval = 0;
unsigned const recsym = find64_secsym_ndx(
w(relhdr->sh_info), txtname, &recval,
&shdr0[symsec_sh_link = w(relhdr->sh_link)],
ehdr);
rel_entsize = w8(relhdr->sh_entsize);
mlocp = sift64_rel_mcount(mlocp,
(void *)mlocp - (void *)mloc0, &mrelp,
relhdr, ehdr, recsym, recval, reltype);
}
}
if (mloc0 != mlocp) {
append64(ehdr, shstr, mloc0, mlocp, mrel0, mrelp,
rel_entsize, symsec_sh_link);
}
free(mrel0);
free(mloc0);
}
static void
do_file(char const *const fname)
{
Elf32_Ehdr *const ehdr = mmap_file(fname);
unsigned int reltype = 0;
ehdr_curr = ehdr;
w = w4nat;
w2 = w2nat;
w8 = w8nat;
switch (ehdr->e_ident[EI_DATA]) {
static unsigned int const endian = 1;
default: {
fprintf(stderr, "unrecognized ELF data encoding %d: %s\n",
ehdr->e_ident[EI_DATA], fname);
fail_file();
} break;
case ELFDATA2LSB: {
if (1 != *(unsigned char const *)&endian) {
/* main() is big endian, file.o is little endian. */
w = w4rev;
w2 = w2rev;
w8 = w8rev;
}
} break;
case ELFDATA2MSB: {
if (0 != *(unsigned char const *)&endian) {
/* main() is little endian, file.o is big endian. */
w = w4rev;
w2 = w2rev;
w8 = w8rev;
}
} break;
} /* end switch */
if (0 != memcmp(ELFMAG, ehdr->e_ident, SELFMAG)
|| ET_REL != w2(ehdr->e_type)
|| EV_CURRENT != ehdr->e_ident[EI_VERSION]) {
fprintf(stderr, "unrecognized ET_REL file %s\n", fname);
fail_file();
}
gpfx = 0;
switch (w2(ehdr->e_machine)) {
default: {
fprintf(stderr, "unrecognized e_machine %d %s\n",
w2(ehdr->e_machine), fname);
fail_file();
} break;
case EM_386: reltype = R_386_32; break;
case EM_ARM: reltype = R_ARM_ABS32; break;
case EM_IA_64: reltype = R_IA64_IMM64; gpfx = '_'; break;
case EM_PPC: reltype = R_PPC_ADDR32; gpfx = '_'; break;
case EM_PPC64: reltype = R_PPC64_ADDR64; gpfx = '_'; break;
case EM_S390: /* reltype: e_class */ gpfx = '_'; break;
case EM_SH: reltype = R_SH_DIR32; break;
case EM_SPARCV9: reltype = R_SPARC_64; gpfx = '_'; break;
case EM_X86_64: reltype = R_X86_64_64; break;
} /* end switch */
switch (ehdr->e_ident[EI_CLASS]) {
default: {
fprintf(stderr, "unrecognized ELF class %d %s\n",
ehdr->e_ident[EI_CLASS], fname);
fail_file();
} break;
case ELFCLASS32: {
if (sizeof(Elf32_Ehdr) != w2(ehdr->e_ehsize)
|| sizeof(Elf32_Shdr) != w2(ehdr->e_shentsize)) {
fprintf(stderr,
"unrecognized ET_REL file: %s\n", fname);
fail_file();
}
if (EM_S390 == w2(ehdr->e_machine))
reltype = R_390_32;
do32(ehdr, fname, reltype);
} break;
case ELFCLASS64: {
Elf64_Ehdr *const ghdr = (Elf64_Ehdr *)ehdr;
if (sizeof(Elf64_Ehdr) != w2(ghdr->e_ehsize)
|| sizeof(Elf64_Shdr) != w2(ghdr->e_shentsize)) {
fprintf(stderr,
"unrecognized ET_REL file: %s\n", fname);
fail_file();
}
if (EM_S390 == w2(ghdr->e_machine))
reltype = R_390_64;
do64(ghdr, fname, reltype);
} break;
} /* end switch */
cleanup();
}
int
main(int argc, char const *argv[])
{
int n_error = 0; /* gcc-4.3.0 false positive complaint */
if (argc <= 1)
fprintf(stderr, "usage: recordmcount file.o...\n");
else /* Process each file in turn, allowing deep failure. */
for (--argc, ++argv; 0 < argc; --argc, ++argv) {
int const sjval = setjmp(jmpenv);
switch (sjval) {
default: {
fprintf(stderr, "internal error: %s\n", argv[0]);
exit(1);
} break;
case SJ_SETJMP: { /* normal sequence */
/* Avoid problems if early cleanup() */
fd_map = -1;
ehdr_curr = NULL;
mmap_failed = 1;
do_file(argv[0]);
} break;
case SJ_FAIL: { /* error in do_file or below */
++n_error;
} break;
case SJ_SUCCEED: { /* premature success */
/* do nothing */
} break;
} /* end switch */
}
return !!n_error;
}
