dt_link.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2005 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#define ELF_TARGET_ALL
#include <elf.h>
#include <sys/types.h>
#include <sys/sysmacros.h>
#include <unistd.h>
#include <strings.h>
#include <alloca.h>
#include <limits.h>
#include <stddef.h>
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <wait.h>
#include <assert.h>
#include <dt_impl.h>
#include <dt_provider.h>
#include <dt_string.h>
#define ESHDR_NULL 0
#define ESHDR_SHSTRTAB 1
#define ESHDR_DOF 2
#define ESHDR_STRTAB 3
#define ESHDR_SYMTAB 4
#define ESHDR_REL 5
#define ESHDR_NUM 6
#define PWRITE_SCN(index, data) \
(lseek64(fd, (off64_t)elf_file.shdr[(index)].sh_offset, SEEK_SET) != \
(off64_t)elf_file.shdr[(index)].sh_offset || \
dt_write(dtp, fd, (data), elf_file.shdr[(index)].sh_size) != \
elf_file.shdr[(index)].sh_size)
static const char DTRACE_SHSTRTAB32[] = "\0"
".shstrtab\0" /* 1 */
".SUNW_dof\0" /* 11 */
".strtab\0" /* 21 */
".symtab\0" /* 29 */
#ifdef __sparc
".rela.SUNW_dof"; /* 37 */
#else
".rel.SUNW_dof"; /* 37 */
#endif
static const char DTRACE_SHSTRTAB64[] = "\0"
".shstrtab\0" /* 1 */
".SUNW_dof\0" /* 11 */
".strtab\0" /* 21 */
".symtab\0" /* 29 */
".rela.SUNW_dof"; /* 37 */
static const char DOFSTR[] = "__SUNW_dof";
static const char DOFLAZYSTR[] = "___SUNW_dof";
typedef struct dof_elf32 {
uint32_t de_nrel; /* relocation count */
#ifdef __sparc
Elf32_Rela *de_rel; /* array of relocations for sparc */
#else
Elf32_Rel *de_rel; /* array of relocations for x86 */
#endif
uint32_t de_nsym; /* symbol count */
Elf32_Sym *de_sym; /* array of symbols */
uint32_t de_strlen; /* size of of string table */
char *de_strtab; /* string table */
uint32_t de_global; /* index of the first global symbol */
} dof_elf32_t;
static int
prepare_elf32(dtrace_hdl_t *dtp, const dof_hdr_t *dof, dof_elf32_t *dep)
{
dof_sec_t *dofs, *s;
dof_relohdr_t *dofrh;
dof_relodesc_t *dofr;
char *strtab;
int i, j, nrel;
size_t strtabsz = 1;
uint32_t count = 0;
size_t base;
Elf32_Sym *sym;
#ifdef __sparc
Elf32_Rela *rel;
#else
Elf32_Rel *rel;
#endif
/*LINTED*/
dofs = (dof_sec_t *)((char *)dof + dof->dofh_secoff);
/*
* First compute the size of the string table and the number of
* relocations present in the DOF.
*/
for (i = 0; i < dof->dofh_secnum; i++) {
if (dofs[i].dofs_type != DOF_SECT_URELHDR)
continue;
/*LINTED*/
dofrh = (dof_relohdr_t *)((char *)dof + dofs[i].dofs_offset);
s = &dofs[dofrh->dofr_strtab];
strtab = (char *)dof + s->dofs_offset;
assert(strtab[0] == '\0');
strtabsz += s->dofs_size - 1;
s = &dofs[dofrh->dofr_relsec];
/*LINTED*/
dofr = (dof_relodesc_t *)((char *)dof + s->dofs_offset);
count += s->dofs_size / s->dofs_entsize;
}
dep->de_strlen = strtabsz;
dep->de_nrel = count;
dep->de_nsym = count + 1; /* the first symbol is always null */
if (dtp->dt_lazyload) {
dep->de_strlen += sizeof (DOFLAZYSTR);
dep->de_nsym++;
} else {
dep->de_strlen += sizeof (DOFSTR);
dep->de_nsym++;
}
if ((dep->de_rel = calloc(dep->de_nrel,
sizeof (dep->de_rel[0]))) == NULL) {
return (dt_set_errno(dtp, EDT_NOMEM));
}
if ((dep->de_sym = calloc(dep->de_nsym, sizeof (Elf32_Sym))) == NULL) {
free(dep->de_rel);
return (dt_set_errno(dtp, EDT_NOMEM));
}
if ((dep->de_strtab = calloc(dep->de_strlen, 1)) == NULL) {
free(dep->de_rel);
free(dep->de_sym);
return (dt_set_errno(dtp, EDT_NOMEM));
}
count = 0;
strtabsz = 1;
dep->de_strtab[0] = '\0';
rel = dep->de_rel;
sym = dep->de_sym;
dep->de_global = 1;
/*
* The first symbol table entry must be zeroed and is always ignored.
*/
bzero(sym, sizeof (Elf32_Sym));
sym++;
/*
* Take a second pass through the DOF sections filling in the
* memory we allocated.
*/
for (i = 0; i < dof->dofh_secnum; i++) {
if (dofs[i].dofs_type != DOF_SECT_URELHDR)
continue;
/*LINTED*/
dofrh = (dof_relohdr_t *)((char *)dof + dofs[i].dofs_offset);
s = &dofs[dofrh->dofr_strtab];
strtab = (char *)dof + s->dofs_offset;
bcopy(strtab + 1, dep->de_strtab + strtabsz, s->dofs_size);
base = strtabsz;
strtabsz += s->dofs_size - 1;
s = &dofs[dofrh->dofr_relsec];
/*LINTED*/
dofr = (dof_relodesc_t *)((char *)dof + s->dofs_offset);
nrel = s->dofs_size / s->dofs_entsize;
s = &dofs[dofrh->dofr_tgtsec];
for (j = 0; j < nrel; j++) {
#if defined(__i386) || defined(__amd64)
rel->r_offset = s->dofs_offset +
dofr[j].dofr_offset;
rel->r_info = ELF32_R_INFO(count + dep->de_global,
R_386_32);
#elif defined(__sparc)
/*
* Add 4 bytes to hit the low half of this 64-bit
* big-endian address.
*/
rel->r_offset = s->dofs_offset +
dofr[j].dofr_offset + 4;
rel->r_info = ELF32_R_INFO(count + dep->de_global,
R_SPARC_32);
#else
#error unknown ISA
#endif
sym->st_name = base + dofr[j].dofr_name - 1;
sym->st_value = 0;
sym->st_size = 0;
sym->st_info = ELF32_ST_INFO(STB_GLOBAL, STT_NOTYPE);
sym->st_other = 0;
sym->st_shndx = SHN_UNDEF;
rel++;
sym++;
count++;
}
}
/*
* Add a symbol for the DOF itself. We use a different symbol for
* lazily and actively loaded DOF to make them easy to distinguish.
*/
sym->st_name = strtabsz;
sym->st_value = 0;
sym->st_size = dof->dofh_filesz;
sym->st_info = ELF32_ST_INFO(STB_GLOBAL, STT_OBJECT);
sym->st_other = 0;
sym->st_shndx = ESHDR_DOF;
sym++;
if (dtp->dt_lazyload) {
bcopy(DOFLAZYSTR, dep->de_strtab + strtabsz,
sizeof (DOFLAZYSTR));
strtabsz += sizeof (DOFLAZYSTR);
} else {
bcopy(DOFSTR, dep->de_strtab + strtabsz, sizeof (DOFSTR));
strtabsz += sizeof (DOFSTR);
}
assert(count == dep->de_nrel);
assert(strtabsz == dep->de_strlen);
return (0);
}
typedef struct dof_elf64 {
uint32_t de_nrel;
Elf64_Rela *de_rel;
uint32_t de_nsym;
Elf64_Sym *de_sym;
uint32_t de_strlen;
char *de_strtab;
uint32_t de_global;
} dof_elf64_t;
static int
prepare_elf64(dtrace_hdl_t *dtp, const dof_hdr_t *dof, dof_elf64_t *dep)
{
dof_sec_t *dofs, *s;
dof_relohdr_t *dofrh;
dof_relodesc_t *dofr;
char *strtab;
int i, j, nrel;
size_t strtabsz = 1;
uint32_t count = 0;
size_t base;
Elf64_Sym *sym;
Elf64_Rela *rel;
/*LINTED*/
dofs = (dof_sec_t *)((char *)dof + dof->dofh_secoff);
/*
* First compute the size of the string table and the number of
* relocations present in the DOF.
*/
for (i = 0; i < dof->dofh_secnum; i++) {
if (dofs[i].dofs_type != DOF_SECT_URELHDR)
continue;
/*LINTED*/
dofrh = (dof_relohdr_t *)((char *)dof + dofs[i].dofs_offset);
s = &dofs[dofrh->dofr_strtab];
strtab = (char *)dof + s->dofs_offset;
assert(strtab[0] == '\0');
strtabsz += s->dofs_size - 1;
s = &dofs[dofrh->dofr_relsec];
/*LINTED*/
dofr = (dof_relodesc_t *)((char *)dof + s->dofs_offset);
count += s->dofs_size / s->dofs_entsize;
}
dep->de_strlen = strtabsz;
dep->de_nrel = count;
dep->de_nsym = count + 1; /* the first symbol is always null */
if (dtp->dt_lazyload) {
dep->de_strlen += sizeof (DOFLAZYSTR);
dep->de_nsym++;
} else {
dep->de_strlen += sizeof (DOFSTR);
dep->de_nsym++;
}
if ((dep->de_rel = calloc(dep->de_nrel,
sizeof (dep->de_rel[0]))) == NULL) {
return (dt_set_errno(dtp, EDT_NOMEM));
}
if ((dep->de_sym = calloc(dep->de_nsym, sizeof (Elf64_Sym))) == NULL) {
free(dep->de_rel);
return (dt_set_errno(dtp, EDT_NOMEM));
}
if ((dep->de_strtab = calloc(dep->de_strlen, 1)) == NULL) {
free(dep->de_rel);
free(dep->de_sym);
return (dt_set_errno(dtp, EDT_NOMEM));
}
count = 0;
strtabsz = 1;
dep->de_strtab[0] = '\0';
rel = dep->de_rel;
sym = dep->de_sym;
dep->de_global = 1;
/*
* The first symbol table entry must be zeroed and is always ignored.
*/
bzero(sym, sizeof (Elf64_Sym));
sym++;
/*
* Take a second pass through the DOF sections filling in the
* memory we allocated.
*/
for (i = 0; i < dof->dofh_secnum; i++) {
if (dofs[i].dofs_type != DOF_SECT_URELHDR)
continue;
/*LINTED*/
dofrh = (dof_relohdr_t *)((char *)dof + dofs[i].dofs_offset);
s = &dofs[dofrh->dofr_strtab];
strtab = (char *)dof + s->dofs_offset;
bcopy(strtab + 1, dep->de_strtab + strtabsz, s->dofs_size);
base = strtabsz;
strtabsz += s->dofs_size - 1;
s = &dofs[dofrh->dofr_relsec];
/*LINTED*/
dofr = (dof_relodesc_t *)((char *)dof + s->dofs_offset);
nrel = s->dofs_size / s->dofs_entsize;
s = &dofs[dofrh->dofr_tgtsec];
for (j = 0; j < nrel; j++) {
#if defined(__i386) || defined(__amd64)
rel->r_offset = s->dofs_offset +
dofr[j].dofr_offset;
rel->r_info = ELF64_R_INFO(count + dep->de_global,
R_AMD64_64);
#elif defined(__sparc)
rel->r_offset = s->dofs_offset +
dofr[j].dofr_offset;
rel->r_info = ELF64_R_INFO(count + dep->de_global,
R_SPARC_64);
#else
#error unknown ISA
#endif
sym->st_name = base + dofr[j].dofr_name - 1;
sym->st_value = 0;
sym->st_size = 0;
sym->st_info = ELF64_ST_INFO(STB_GLOBAL, STT_NOTYPE);
sym->st_other = 0;
sym->st_shndx = SHN_UNDEF;
rel++;
sym++;
count++;
}
}
/*
* Add a symbol for the DOF itself. We use a different symbol for
* lazily and actively loaded DOF to make them easy to distinguish.
*/
sym->st_name = strtabsz;
sym->st_value = 0;
sym->st_size = dof->dofh_filesz;
sym->st_info = ELF64_ST_INFO(STB_GLOBAL, STT_OBJECT);
sym->st_other = 0;
sym->st_shndx = ESHDR_DOF;
sym++;
if (dtp->dt_lazyload) {
bcopy(DOFLAZYSTR, dep->de_strtab + strtabsz,
sizeof (DOFLAZYSTR));
strtabsz += sizeof (DOFLAZYSTR);
} else {
bcopy(DOFSTR, dep->de_strtab + strtabsz, sizeof (DOFSTR));
strtabsz += sizeof (DOFSTR);
}
assert(count == dep->de_nrel);
assert(strtabsz == dep->de_strlen);
return (0);
}
/*
* Write out an ELF32 file prologue consisting of a header, section headers,
* and a section header string table. The DOF data will follow this prologue
* and complete the contents of the given ELF file.
*/
static int
dump_elf32(dtrace_hdl_t *dtp, const dof_hdr_t *dof, int fd)
{
struct {
Elf32_Ehdr ehdr;
Elf32_Shdr shdr[ESHDR_NUM];
} elf_file;
Elf32_Shdr *shp;
Elf32_Off off;
dof_elf32_t de;
int ret = 0;
uint_t nshdr;
if (prepare_elf32(dtp, dof, &de) != 0)
return (-1); /* errno is set for us */
/*
* If there are no relocations, we only need enough sections for
* the shstrtab and the DOF.
*/
nshdr = de.de_nrel == 0 ? ESHDR_SYMTAB + 1 : ESHDR_NUM;
bzero(&elf_file, sizeof (elf_file));
elf_file.ehdr.e_ident[EI_MAG0] = ELFMAG0;
elf_file.ehdr.e_ident[EI_MAG1] = ELFMAG1;
elf_file.ehdr.e_ident[EI_MAG2] = ELFMAG2;
elf_file.ehdr.e_ident[EI_MAG3] = ELFMAG3;
elf_file.ehdr.e_ident[EI_VERSION] = EV_CURRENT;
elf_file.ehdr.e_ident[EI_CLASS] = ELFCLASS32;
#if defined(_BIG_ENDIAN)
elf_file.ehdr.e_ident[EI_DATA] = ELFDATA2MSB;
#elif defined(_LITTLE_ENDIAN)
elf_file.ehdr.e_ident[EI_DATA] = ELFDATA2LSB;
#endif
elf_file.ehdr.e_type = ET_REL;
#if defined(__sparc)
elf_file.ehdr.e_machine = EM_SPARC;
#elif defined(__i386) || defined(__amd64)
elf_file.ehdr.e_machine = EM_386;
#endif
elf_file.ehdr.e_version = EV_CURRENT;
elf_file.ehdr.e_shoff = sizeof (Elf32_Ehdr);
elf_file.ehdr.e_ehsize = sizeof (Elf32_Ehdr);
elf_file.ehdr.e_phentsize = sizeof (Elf32_Phdr);
elf_file.ehdr.e_shentsize = sizeof (Elf32_Shdr);
elf_file.ehdr.e_shnum = nshdr;
elf_file.ehdr.e_shstrndx = ESHDR_SHSTRTAB;
off = sizeof (elf_file) + nshdr * sizeof (Elf32_Shdr);
shp = &elf_file.shdr[ESHDR_SHSTRTAB];
shp->sh_name = 1; /* DTRACE_SHSTRTAB32[1] = ".shstrtab" */
shp->sh_type = SHT_STRTAB;
shp->sh_offset = off;
shp->sh_size = sizeof (DTRACE_SHSTRTAB32);
shp->sh_addralign = sizeof (char);
off = P2ROUNDUP(shp->sh_offset + shp->sh_size, 8);
shp = &elf_file.shdr[ESHDR_DOF];
shp->sh_name = 11; /* DTRACE_SHSTRTAB32[11] = ".SUNW_dof" */
shp->sh_flags = SHF_ALLOC;
shp->sh_type = SHT_SUNW_dof;
shp->sh_offset = off;
shp->sh_size = dof->dofh_filesz;
shp->sh_addralign = 8;
off = shp->sh_offset + shp->sh_size;
shp = &elf_file.shdr[ESHDR_STRTAB];
shp->sh_name = 21; /* DTRACE_SHSTRTAB32[21] = ".strtab" */
shp->sh_flags = SHF_ALLOC;
shp->sh_type = SHT_STRTAB;
shp->sh_offset = off;
shp->sh_size = de.de_strlen;
shp->sh_addralign = sizeof (char);
off = P2ROUNDUP(shp->sh_offset + shp->sh_size, 4);
shp = &elf_file.shdr[ESHDR_SYMTAB];
shp->sh_name = 29; /* DTRACE_SHSTRTAB32[29] = ".symtab" */
shp->sh_flags = SHF_ALLOC;
shp->sh_type = SHT_SYMTAB;
shp->sh_entsize = sizeof (Elf32_Sym);
shp->sh_link = ESHDR_STRTAB;
shp->sh_offset = off;
shp->sh_info = de.de_global;
shp->sh_size = de.de_nsym * sizeof (Elf32_Sym);
shp->sh_addralign = 4;
off = P2ROUNDUP(shp->sh_offset + shp->sh_size, 4);
if (de.de_nrel == 0) {
if (dt_write(dtp, fd, &elf_file,
sizeof (elf_file)) != sizeof (elf_file) ||
PWRITE_SCN(ESHDR_SHSTRTAB, DTRACE_SHSTRTAB32) ||
PWRITE_SCN(ESHDR_STRTAB, de.de_strtab) ||
PWRITE_SCN(ESHDR_SYMTAB, de.de_sym) ||
PWRITE_SCN(ESHDR_DOF, dof)) {
ret = dt_set_errno(dtp, errno);
}
} else {
shp = &elf_file.shdr[ESHDR_REL];
shp->sh_name = 37; /* DTRACE_SHSTRTAB32[37] = ".rel.SUNW_dof" */
shp->sh_flags = SHF_ALLOC;
#ifdef __sparc
shp->sh_type = SHT_RELA;
#else
shp->sh_type = SHT_REL;
#endif
shp->sh_entsize = sizeof (de.de_rel[0]);
shp->sh_link = ESHDR_SYMTAB;
shp->sh_info = ESHDR_DOF;
shp->sh_offset = off;
shp->sh_size = de.de_nrel * sizeof (de.de_rel[0]);
shp->sh_addralign = 4;
if (dt_write(dtp, fd, &elf_file,
sizeof (elf_file)) != sizeof (elf_file) ||
PWRITE_SCN(ESHDR_SHSTRTAB, DTRACE_SHSTRTAB32) ||
PWRITE_SCN(ESHDR_STRTAB, de.de_strtab) ||
PWRITE_SCN(ESHDR_SYMTAB, de.de_sym) ||
PWRITE_SCN(ESHDR_REL, de.de_rel) ||
PWRITE_SCN(ESHDR_DOF, dof)) {
ret = dt_set_errno(dtp, errno);
}
}
free(de.de_strtab);
free(de.de_sym);
free(de.de_rel);
return (ret);
}
/*
* Write out an ELF64 file prologue consisting of a header, section headers,
* and a section header string table. The DOF data will follow this prologue
* and complete the contents of the given ELF file.
*/
static int
dump_elf64(dtrace_hdl_t *dtp, const dof_hdr_t *dof, int fd)
{
struct {
Elf64_Ehdr ehdr;
Elf64_Shdr shdr[ESHDR_NUM];
} elf_file;
Elf64_Shdr *shp;
Elf64_Off off;
dof_elf64_t de;
int ret = 0;
uint_t nshdr;
if (prepare_elf64(dtp, dof, &de) != 0)
return (-1); /* errno is set for us */
/*
* If there are no relocations, we only need enough sections for
* the shstrtab and the DOF.
*/
nshdr = de.de_nrel == 0 ? ESHDR_SYMTAB + 1 : ESHDR_NUM;
bzero(&elf_file, sizeof (elf_file));
elf_file.ehdr.e_ident[EI_MAG0] = ELFMAG0;
elf_file.ehdr.e_ident[EI_MAG1] = ELFMAG1;
elf_file.ehdr.e_ident[EI_MAG2] = ELFMAG2;
elf_file.ehdr.e_ident[EI_MAG3] = ELFMAG3;
elf_file.ehdr.e_ident[EI_VERSION] = EV_CURRENT;
elf_file.ehdr.e_ident[EI_CLASS] = ELFCLASS64;
#if defined(_BIG_ENDIAN)
elf_file.ehdr.e_ident[EI_DATA] = ELFDATA2MSB;
#elif defined(_LITTLE_ENDIAN)
elf_file.ehdr.e_ident[EI_DATA] = ELFDATA2LSB;
#endif
elf_file.ehdr.e_type = ET_REL;
#if defined(__sparc)
elf_file.ehdr.e_machine = EM_SPARCV9;
#elif defined(__i386) || defined(__amd64)
elf_file.ehdr.e_machine = EM_AMD64;
#endif
elf_file.ehdr.e_version = EV_CURRENT;
elf_file.ehdr.e_shoff = sizeof (Elf64_Ehdr);
elf_file.ehdr.e_ehsize = sizeof (Elf64_Ehdr);
elf_file.ehdr.e_phentsize = sizeof (Elf64_Phdr);
elf_file.ehdr.e_shentsize = sizeof (Elf64_Shdr);
elf_file.ehdr.e_shnum = nshdr;
elf_file.ehdr.e_shstrndx = ESHDR_SHSTRTAB;
off = sizeof (elf_file) + nshdr * sizeof (Elf64_Shdr);
shp = &elf_file.shdr[ESHDR_SHSTRTAB];
shp->sh_name = 1; /* DTRACE_SHSTRTAB64[1] = ".shstrtab" */
shp->sh_type = SHT_STRTAB;
shp->sh_offset = off;
shp->sh_size = sizeof (DTRACE_SHSTRTAB64);
shp->sh_addralign = sizeof (char);
off = P2ROUNDUP(shp->sh_offset + shp->sh_size, 8);
shp = &elf_file.shdr[ESHDR_DOF];
shp->sh_name = 11; /* DTRACE_SHSTRTAB64[11] = ".SUNW_dof" */
shp->sh_flags = SHF_ALLOC;
shp->sh_type = SHT_SUNW_dof;
shp->sh_offset = off;
shp->sh_size = dof->dofh_filesz;
shp->sh_addralign = 8;
off = shp->sh_offset + shp->sh_size;
shp = &elf_file.shdr[ESHDR_STRTAB];
shp->sh_name = 21; /* DTRACE_SHSTRTAB64[21] = ".strtab" */
shp->sh_flags = SHF_ALLOC;
shp->sh_type = SHT_STRTAB;
shp->sh_offset = off;
shp->sh_size = de.de_strlen;
shp->sh_addralign = sizeof (char);
off = P2ROUNDUP(shp->sh_offset + shp->sh_size, 8);
shp = &elf_file.shdr[ESHDR_SYMTAB];
shp->sh_name = 29; /* DTRACE_SHSTRTAB64[29] = ".symtab" */
shp->sh_flags = SHF_ALLOC;
shp->sh_type = SHT_SYMTAB;
shp->sh_entsize = sizeof (Elf64_Sym);
shp->sh_link = ESHDR_STRTAB;
shp->sh_offset = off;
shp->sh_info = de.de_global;
shp->sh_size = de.de_nsym * sizeof (Elf64_Sym);
shp->sh_addralign = 8;
off = P2ROUNDUP(shp->sh_offset + shp->sh_size, 8);
if (de.de_nrel == 0) {
if (dt_write(dtp, fd, &elf_file,
sizeof (elf_file)) != sizeof (elf_file) ||
PWRITE_SCN(ESHDR_SHSTRTAB, DTRACE_SHSTRTAB64) ||
PWRITE_SCN(ESHDR_STRTAB, de.de_strtab) ||
PWRITE_SCN(ESHDR_SYMTAB, de.de_sym) ||
PWRITE_SCN(ESHDR_DOF, dof)) {
ret = dt_set_errno(dtp, errno);
}
} else {
shp = &elf_file.shdr[ESHDR_REL];
shp->sh_name = 37; /* DTRACE_SHSTRTAB64[37] = ".rel.SUNW_dof" */
shp->sh_flags = SHF_ALLOC;
shp->sh_type = SHT_RELA;
shp->sh_entsize = sizeof (de.de_rel[0]);
shp->sh_link = ESHDR_SYMTAB;
shp->sh_info = ESHDR_DOF;
shp->sh_offset = off;
shp->sh_size = de.de_nrel * sizeof (de.de_rel[0]);
shp->sh_addralign = 8;
if (dt_write(dtp, fd, &elf_file,
sizeof (elf_file)) != sizeof (elf_file) ||
PWRITE_SCN(ESHDR_SHSTRTAB, DTRACE_SHSTRTAB64) ||
PWRITE_SCN(ESHDR_STRTAB, de.de_strtab) ||
PWRITE_SCN(ESHDR_SYMTAB, de.de_sym) ||
PWRITE_SCN(ESHDR_REL, de.de_rel) ||
PWRITE_SCN(ESHDR_DOF, dof)) {
ret = dt_set_errno(dtp, errno);
}
}
free(de.de_strtab);
free(de.de_sym);
free(de.de_rel);
return (ret);
}
static int
dt_symtab_lookup(Elf_Data *data_sym, uintptr_t addr, uint_t shn, GElf_Sym *sym)
{
int i, ret = -1;
GElf_Sym s;
for (i = 0; gelf_getsym(data_sym, i, sym) != NULL; i++) {
if (GELF_ST_TYPE(sym->st_info) == STT_FUNC &&
shn == sym->st_shndx &&
sym->st_value <= addr &&
addr < sym->st_value + sym->st_size) {
if (GELF_ST_BIND(sym->st_info) == STB_GLOBAL)
return (0);
ret = 0;
s = *sym;
}
}
if (ret == 0)
*sym = s;
return (ret);
}
#if defined(__sparc)
#define DT_OP_RET 0x81c7e008
#define DT_OP_NOP 0x01000000
#define DT_OP_CALL 0x40000000
#define DT_IS_MOV_O7(inst) (((inst) & 0xffffe000) == 0x9e100000)
#define DT_IS_RESTORE(inst) (((inst) & 0xc1f80000) == 0x81e80000)
#define DT_IS_RETL(inst) (((inst) & 0xfff83fff) == 0x81c02008)
#define DT_RS2(inst) ((inst) & 0x1f)
#define DT_MAKE_RETL(reg) (0x81c02008 | ((reg) << 14))
static int
dt_modtext(char *p, GElf_Rela *rela, uint32_t *off)
{
uint32_t *ip;
if ((rela->r_offset & (sizeof (uint32_t) - 1)) != 0)
return (-1);
/*LINTED*/
ip = (uint32_t *)(p + rela->r_offset);
/*
* We only know about some specific relocation types.
*/
if (GELF_R_TYPE(rela->r_info) != R_SPARC_WDISP30 &&
GELF_R_TYPE(rela->r_info) != R_SPARC_WPLT30)
return (-1);
/*
* We may have already processed this object file in an earlier
* linker invocation in which case we'd expect to see a ret/restore
* pair, a retl-like/mov pair or a nop; return success in that case.
*/
if (DT_IS_RESTORE(ip[1])) {
if (ip[0] == DT_OP_RET) {
return (0);
}
} else if (DT_IS_MOV_O7(ip[1])) {
if (DT_IS_RETL(ip[0])) {
return (0);
}
} else {
if (ip[0] == DT_OP_NOP) {
(*off) += sizeof (ip[0]);
return (0);
}
}
/*
* We only expect call instructions with a displacement of 0.
*/
if (ip[0] != DT_OP_CALL) {
dt_dprintf("found %x instead of a call instruction at %llx\n",
ip[0], (u_longlong_t)rela->r_offset);
return (-1);
}
/*
* If the call is followed by a restore, it's a tail call so change
* the call to a ret. If the call if followed by a mov of a register
* into %o7, it's a tail call in leaf context so change the call to
* a retl-like instruction that returns to that register value + 8
* (rather than the typical %o7 + 8). Otherwise we adjust the offset
* to land on what was once the delay slot of the call so we
* correctly get all the arguments.
*/
if (DT_IS_RESTORE(ip[1])) {
ip[0] = DT_OP_RET;
} else if (DT_IS_MOV_O7(ip[1])) {
ip[0] = DT_MAKE_RETL(DT_RS2(ip[1]));
} else {
ip[0] = DT_OP_NOP;
(*off) += sizeof (ip[0]);
}
return (0);
}
#elif defined(__i386) || defined(__amd64)
#define DT_OP_NOP 0x90
#define DT_OP_CALL 0xe8
static int
dt_modtext(char *p, GElf_Rela *rela, uint32_t *off)
{
uint8_t *ip = (uint8_t *)(p + rela->r_offset - 1);
/*
* On x86, the first byte of the instruction is the call opcode and
* the next four bytes are the 32-bit address; the relocation is for
* the address so we back up one byte to land on the opcode.
*/
(*off) -= 1;
/*
* We only know about some specific relocation types. Luckily
* these types have the same values on both 32-bit and 64-bit
* x86 architectures.
*/
if (GELF_R_TYPE(rela->r_info) != R_386_PC32 &&
GELF_R_TYPE(rela->r_info) != R_386_PLT32)
return (-1);
/*
* We may have already processed this object file in an earlier
* linker invocation in which case we'd expect to see a bunch
* of nops; return success in that case.
*/
if (ip[0] == DT_OP_NOP && ip[1] == DT_OP_NOP && ip[2] == DT_OP_NOP &&
ip[3] == DT_OP_NOP && ip[4] == DT_OP_NOP)
return (0);
/*
* We only expect a call instrution with a 32-bit displacement.
*/
if (ip[0] != DT_OP_CALL) {
dt_dprintf("found %x instead of a call instruction at %llx\n",
ip[0], (u_longlong_t)rela->r_offset);
return (-1);
}
ip[0] = DT_OP_NOP;
ip[1] = DT_OP_NOP;
ip[2] = DT_OP_NOP;
ip[3] = DT_OP_NOP;
ip[4] = DT_OP_NOP;
return (0);
}
#else
#error unknown ISA
#endif
/*PRINTFLIKE2*/
static int
dt_link_error(dtrace_hdl_t *dtp, const char *format, ...)
{
va_list ap;
va_start(ap, format);
dt_set_errmsg(dtp, NULL, NULL, NULL, 0, format, ap);
va_end(ap);
return (dt_set_errno(dtp, EDT_COMPILER));
}
static int
process_obj(dtrace_hdl_t *dtp, const char *obj)
{
static const char dt_prefix[] = "__dtrace_";
int fd, i, ndx, mod = 0;
Elf *elf;
GElf_Ehdr ehdr;
Elf_Scn *scn_rel, *scn_sym, *scn_tgt;
Elf_Data *data_rel, *data_sym, *data_tgt;
GElf_Shdr shdr_rel, shdr_sym, shdr_tgt;
GElf_Sym rsym, fsym;
GElf_Rela rela;
GElf_Rel rel;
char *s, *p;
char pname[DTRACE_PROVNAMELEN];
dt_provider_t *pvp;
dt_probe_t *prp;
uint32_t off, eclass, emachine1, emachine2;
if ((fd = open64(obj, O_RDWR)) == -1) {
return (dt_link_error(dtp, "failed to open %s: %s", obj,
strerror(errno)));
}
if (elf_version(EV_CURRENT) == EV_NONE ||
(elf = elf_begin(fd, ELF_C_RDWR, NULL)) == NULL) {
return (dt_link_error(dtp, "failed to process %s: %s", obj,
elf_errmsg(elf_errno())));
}
switch (elf_kind(elf)) {
case ELF_K_ELF:
break;
case ELF_K_AR:
return (dt_link_error(dtp, "archive files are not permitted %s;"
" use the contents of the archive instead", obj));
default:
return (dt_link_error(dtp, "invalid file type for %s", obj));
}
if (gelf_getehdr(elf, &ehdr) == NULL)
return (dt_link_error(dtp, "corrupt object file %s", obj));
if (dtp->dt_oflags & DTRACE_O_LP64) {
eclass = ELFCLASS64;
#if defined(__sparc)
emachine1 = emachine2 = EM_SPARCV9;
#elif defined(__i386) || defined(__amd64)
emachine1 = emachine2 = EM_AMD64;
#endif
} else {
eclass = ELFCLASS32;
#if defined(__sparc)
emachine1 = EM_SPARC;
emachine2 = EM_SPARC32PLUS;
#elif defined(__i386) || defined(__amd64)
emachine1 = emachine2 = EM_386;
#endif
}
if (ehdr.e_ident[EI_CLASS] != eclass)
return (dt_link_error(dtp, "incorrect ELF class for object "
"file %s", obj));
if (ehdr.e_machine != emachine1 && ehdr.e_machine != emachine2)
return (dt_link_error(dtp, "incorrect ELF machine type for "
"object file %s", obj));
scn_rel = NULL;
while ((scn_rel = elf_nextscn(elf, scn_rel)) != NULL) {
if (gelf_getshdr(scn_rel, &shdr_rel) == NULL)
goto err;
if (shdr_rel.sh_type != SHT_RELA && shdr_rel.sh_type != SHT_REL)
continue;
if ((data_rel = elf_getdata(scn_rel, NULL)) == NULL)
goto err;
if ((scn_sym = elf_getscn(elf, shdr_rel.sh_link)) == NULL ||
gelf_getshdr(scn_sym, &shdr_sym) == NULL ||
(data_sym = elf_getdata(scn_sym, NULL)) == NULL)
goto err;
if ((scn_tgt = elf_getscn(elf, shdr_rel.sh_info)) == NULL ||
gelf_getshdr(scn_tgt, &shdr_tgt) == NULL ||
(data_tgt = elf_getdata(scn_tgt, NULL)) == NULL)
goto err;
for (i = 0; i < shdr_rel.sh_size / shdr_rel.sh_entsize; i++) {
if (shdr_rel.sh_type == SHT_RELA) {
if (gelf_getrela(data_rel, i, &rela) == NULL)
continue;
} else {
if (gelf_getrel(data_rel, i, &rel) == NULL)
continue;
rela.r_offset = rel.r_offset;
rela.r_info = rel.r_info;
rela.r_addend = 0;
}
ndx = GELF_R_SYM(rela.r_info);
if (gelf_getsym(data_sym, ndx, &rsym) == NULL ||
(s = elf_strptr(elf, shdr_sym.sh_link,
rsym.st_name)) == NULL)
goto err;
if (strncmp(s, dt_prefix, sizeof (dt_prefix) - 1) != 0)
continue;
if (dt_symtab_lookup(data_sym, rela.r_offset,
shdr_rel.sh_info, &fsym) != 0)
goto err;
s += sizeof (dt_prefix) - 1;
if ((p = strstr(s, "___")) == NULL ||
p - s >= sizeof (pname))
goto err;
(void) memcpy(pname, s, p - s);
pname[p - s] = '\0';
p = strhyphenate(p + 3); /* strlen("___") */
if ((s = elf_strptr(elf, shdr_sym.sh_link,
fsym.st_name)) == NULL)
goto err;
if ((pvp = dt_provider_lookup(dtp, pname)) == NULL) {
return (dt_link_error(dtp,
"no such provider %s", pname));
}
if ((prp = dt_probe_lookup(pvp, p)) == NULL) {
return (dt_link_error(dtp,
"no such probe %s", p));
}
assert(fsym.st_value <= rela.r_offset);
off = rela.r_offset - fsym.st_value;
if (dt_modtext(data_tgt->d_buf, &rela, &off) != 0)
goto err;
if (dt_probe_define(pvp, prp, s, off) != 0)
return (dt_set_errno(dtp, EDT_NOMEM));
mod = 1;
/*
* This symbol may already have been marked to
* be ignored by another relocation referencing
* the same symbol or if this object file has
* already been processed by an earlier link
* invocation.
*/
if (rsym.st_shndx != SHN_SUNW_IGNORE) {
rsym.st_shndx = SHN_SUNW_IGNORE;
(void) gelf_update_sym(data_sym, ndx, &rsym);
}
}
}
if (mod && elf_update(elf, ELF_C_WRITE) == -1)
goto err;
return (0);
err:
return (dt_link_error(dtp,
"an error was encountered while processing %s", obj));
}
int
dtrace_program_link(dtrace_hdl_t *dtp, dtrace_prog_t *pgp, uint_t dflags,
const char *file, int objc, char *const objv[])
{
char drti[PATH_MAX];
dof_hdr_t *dof;
int fd, status, i;
char *cmd, tmp;
size_t len;
int ret = 0;
for (i = 0; i < objc; i++) {
if (process_obj(dtp, objv[i]) != 0)
return (-1); /* errno is set for us */
}
if ((dof = dtrace_dof_create(dtp, pgp, dflags)) == NULL)
return (-1); /* errno is set for us */
/*
* Create a temporary file and then unlink it if we're going to
* combine it with drti.o later. We can still refer to it in child
* processes as /dev/fd/<fd>.
*/
if ((fd = open64(file, O_RDWR | O_CREAT | O_TRUNC, 0666)) == -1) {
return (dt_link_error(dtp,
"failed to open %s: %s", file, strerror(errno)));
}
/*
* If -xlinktype=DOF has been selected, just write out the DOF.
* Otherwise proceed to the default of generating and linking ELF.
*/
switch (dtp->dt_linktype) {
case DT_LTYP_DOF:
if (dt_write(dtp, fd, dof, dof->dofh_filesz) < dof->dofh_filesz)
ret = errno;
if (close(fd) != 0 && ret == 0)
ret = errno;
if (ret != 0) {
return (dt_link_error(dtp,
"failed to write %s: %s", file, strerror(ret)));
}
return (0);
case DT_LTYP_ELF:
break; /* fall through to the rest of dtrace_program_link() */
default:
return (dt_link_error(dtp,
"invalid link type %u\n", dtp->dt_linktype));
}
if (!dtp->dt_lazyload)
(void) unlink(file);
if (dtp->dt_oflags & DTRACE_O_LP64)
status = dump_elf64(dtp, dof, fd);
else
status = dump_elf32(dtp, dof, fd);
if (status != 0 || lseek(fd, 0, SEEK_SET) != 0) {
return (dt_link_error(dtp,
"failed to write %s: %s", file, strerror(errno)));
}
if (!dtp->dt_lazyload) {
if (dtp->dt_oflags & DTRACE_O_LP64) {
(void) snprintf(drti, sizeof (drti),
"%s/64/drti.o", _dtrace_libdir);
} else {
(void) snprintf(drti, sizeof (drti),
"%s/drti.o", _dtrace_libdir);
}
len = snprintf(&tmp, 1, "%s -o %s -r /dev/fd/%d %s",
dtp->dt_ld_path, file, fd, drti) + 1;
cmd = alloca(len);
(void) snprintf(cmd, len, "%s -o %s -r /dev/fd/%d %s",
dtp->dt_ld_path, file, fd, drti);
if ((status = system(cmd)) == -1) {
ret = dt_link_error(dtp, "failed to run %s: %s",
dtp->dt_ld_path, strerror(errno));
goto done;
}
(void) close(fd); /* release temporary file */
if (WIFSIGNALED(status)) {
ret = dt_link_error(dtp,
"failed to link %s: %s failed due to signal %d",
file, dtp->dt_ld_path, WTERMSIG(status));
goto done;
}
if (WEXITSTATUS(status) != 0) {
ret = dt_link_error(dtp,
"failed to link %s: %s exited with status %d\n",
file, dtp->dt_ld_path, WEXITSTATUS(status));
goto done;
}
} else {
(void) close(fd);
}
done:
dtrace_dof_destroy(dtp, dof);
return (ret);
}