diff options
Diffstat (limited to 'cddl/contrib/opensolaris/lib/libdtrace/common/dt_link.c')
| -rw-r--r-- | cddl/contrib/opensolaris/lib/libdtrace/common/dt_link.c | 1913 |
1 files changed, 1913 insertions, 0 deletions
diff --git a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_link.c b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_link.c new file mode 100644 index 000000000000..442c6f940733 --- /dev/null +++ b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_link.c @@ -0,0 +1,1913 @@ +/* + * CDDL HEADER START + * + * The contents of this file are subject to the terms of the + * Common Development and Distribution License (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 2008 Sun Microsystems, Inc. All rights reserved. + * Use is subject to license terms. + * Copyright 2017-2018 Mark Johnston <markj@FreeBSD.org> + */ + +#include <sys/param.h> +#include <sys/mman.h> +#include <sys/wait.h> + +#include <assert.h> +#include <elf.h> +#include <sys/types.h> +#include <fcntl.h> +#include <gelf.h> +#include <limits.h> +#include <stddef.h> +#include <stdio.h> +#include <stdlib.h> +#include <strings.h> +#include <errno.h> +#include <unistd.h> + +#include <libelf.h> + +#include <dt_impl.h> +#include <dt_provider.h> +#include <dt_program.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 */ +".rel.SUNW_dof"; /* 37 */ + +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 dt_link_pair { + struct dt_link_pair *dlp_next; /* next pair in linked list */ + void *dlp_str; /* buffer for string table */ + void *dlp_sym; /* buffer for symbol table */ +} dt_link_pair_t; + +typedef struct dof_elf32 { + uint32_t de_nrel; /* relocation count */ + Elf32_Rel *de_rel; /* array of relocations for x86 */ + 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; + Elf32_Rel *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 (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(__aarch64__) + rel->r_offset = s->dofs_offset + + dofr[j].dofr_offset; + rel->r_info = ELF32_R_INFO(count + dep->de_global, + R_ARM_REL32); +#elif defined(__arm__) +/* XXX */ + printf("%s:%s(%d): arm not implemented\n", + __FUNCTION__, __FILE__, __LINE__); +#elif 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_PC32); +#elif defined(__powerpc__) + /* + * 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_PPC_REL32); +#elif defined(__riscv) + rel->r_offset = s->dofs_offset + dofr[j].dofr_offset; + rel->r_info = ELF32_R_INFO(count + dep->de_global, + R_RISCV_32_PCREL); +#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_FUNC); + sym->st_other = ELF32_ST_VISIBILITY(STV_HIDDEN); + 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 = ELF32_ST_VISIBILITY(STV_HIDDEN); + 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; + uint64_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(__aarch64__) + rel->r_offset = s->dofs_offset + + dofr[j].dofr_offset; + rel->r_info = ELF64_R_INFO(count + dep->de_global, + R_AARCH64_PREL64); +#elif defined(__arm__) +/* XXX */ +#elif defined(__powerpc__) + rel->r_offset = s->dofs_offset + + dofr[j].dofr_offset; + rel->r_info = ELF64_R_INFO(count + dep->de_global, + R_PPC64_REL64); +#elif defined(__riscv) + rel->r_offset = s->dofs_offset + dofr[j].dofr_offset; + rel->r_info = ELF64_R_INFO(count + dep->de_global, + R_RISCV_32_PCREL); +#elif 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_X86_64_PC64); +#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 = GELF_ST_INFO(STB_GLOBAL, STT_FUNC); + sym->st_other = ELF64_ST_VISIBILITY(STV_HIDDEN); + 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 = GELF_ST_INFO(STB_GLOBAL, STT_OBJECT); + sym->st_other = ELF64_ST_VISIBILITY(STV_HIDDEN); + 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 BYTE_ORDER == _BIG_ENDIAN + elf_file.ehdr.e_ident[EI_DATA] = ELFDATA2MSB; +#else + elf_file.ehdr.e_ident[EI_DATA] = ELFDATA2LSB; +#endif + elf_file.ehdr.e_ident[EI_OSABI] = ELFOSABI_FREEBSD; + elf_file.ehdr.e_type = ET_REL; +#if defined(__arm__) + elf_file.ehdr.e_machine = EM_ARM; +#elif defined(__powerpc__) + elf_file.ehdr.e_machine = EM_PPC; +#elif defined(__i386) || defined(__amd64) + elf_file.ehdr.e_machine = EM_386; +#elif defined(__aarch64__) + elf_file.ehdr.e_machine = EM_AARCH64; +#elif defined(__riscv) + elf_file.ehdr.e_machine = EM_RISCV; + + /* Set the ELF flags according to our current ABI */ +#if defined(__riscv_compressed) + elf_file.ehdr.e_flags |= EF_RISCV_RVC; +#endif +#if defined(__riscv_float_abi_soft) + elf_file.ehdr.e_flags |= EF_RISCV_FLOAT_ABI_SOFT; +#endif +#if defined(__riscv_float_abi_single) + elf_file.ehdr.e_flags |= EF_RISCV_FLOAT_ABI_SINGLE; +#endif +#if defined(__riscv_float_abi_double) + elf_file.ehdr.e_flags |= EF_RISCV_FLOAT_ABI_DOUBLE; +#endif +#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 = roundup2(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 = roundup2(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 = roundup2(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 = 0; + shp->sh_type = SHT_REL; + 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 BYTE_ORDER == _BIG_ENDIAN + elf_file.ehdr.e_ident[EI_DATA] = ELFDATA2MSB; +#else + elf_file.ehdr.e_ident[EI_DATA] = ELFDATA2LSB; +#endif + elf_file.ehdr.e_ident[EI_OSABI] = ELFOSABI_FREEBSD; + elf_file.ehdr.e_type = ET_REL; +#if defined(__arm__) + elf_file.ehdr.e_machine = EM_ARM; +#elif defined(__powerpc64__) +#if defined(_CALL_ELF) && _CALL_ELF == 2 + elf_file.ehdr.e_flags = 2; +#endif + elf_file.ehdr.e_machine = EM_PPC64; +#elif defined(__i386) || defined(__amd64) + elf_file.ehdr.e_machine = EM_AMD64; +#elif defined(__aarch64__) + elf_file.ehdr.e_machine = EM_AARCH64; +#elif defined(__riscv) + elf_file.ehdr.e_machine = EM_RISCV; + + /* Set the ELF flags according to our current ABI */ +#if defined(__riscv_compressed) + elf_file.ehdr.e_flags |= EF_RISCV_RVC; +#endif +#if defined(__riscv_float_abi_soft) + elf_file.ehdr.e_flags |= EF_RISCV_FLOAT_ABI_SOFT; +#endif +#if defined(__riscv_float_abi_single) + elf_file.ehdr.e_flags |= EF_RISCV_FLOAT_ABI_SINGLE; +#endif +#if defined(__riscv_float_abi_double) + elf_file.ehdr.e_flags |= EF_RISCV_FLOAT_ABI_DOUBLE; +#endif +#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 = roundup2(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 = roundup2(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 = roundup2(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 = 0; + 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, int start, int end, uintptr_t addr, + uint_t shn, GElf_Sym *sym, int uses_funcdesc, Elf *elf) +{ + Elf64_Addr symval; + Elf_Scn *opd_scn; + Elf_Data *opd_desc; + int i; + + for (i = start; i < end && gelf_getsym(data_sym, i, sym) != NULL; i++) { + if (GELF_ST_TYPE(sym->st_info) == STT_FUNC) { + symval = sym->st_value; + if (uses_funcdesc) { + opd_scn = elf_getscn(elf, sym->st_shndx); + opd_desc = elf_rawdata(opd_scn, NULL); + symval = + *(uint64_t*)((char *)opd_desc->d_buf + symval); + } + if ((uses_funcdesc || shn == sym->st_shndx) && + symval <= addr && addr < symval + sym->st_size) + return (0); + } + } + + return (-1); +} + +#if defined(__aarch64__) +#define DT_OP_NOP 0xd503201f +#define DT_OP_RET 0xd65f03c0 +#define DT_OP_CALL26 0x94000000 +#define DT_OP_JUMP26 0x14000000 +#define DT_REL_NONE R_AARCH64_NONE + +static int +dt_modtext(dtrace_hdl_t *dtp, char *p, int isenabled, GElf_Rela *rela, + uint32_t *off) +{ + uint32_t *ip; + + /* + * Ensure that the offset is aligned on an instruction boundary. + */ + if ((rela->r_offset & (sizeof (uint32_t) - 1)) != 0) + return (-1); + + /* + * We only know about some specific relocation types. + * We also recognize relocation type NONE, since that gets used for + * relocations of USDT probes, and we might be re-processing a file. + */ + if (GELF_R_TYPE(rela->r_info) != R_AARCH64_CALL26 && + GELF_R_TYPE(rela->r_info) != R_AARCH64_JUMP26 && + GELF_R_TYPE(rela->r_info) != R_AARCH64_NONE) + return (-1); + + ip = (uint32_t *)(p + rela->r_offset); + + /* + * We may have already processed this object file in an earlier linker + * invocation. Check to see if the present instruction sequence matches + * the one we would install below. + */ + if (ip[0] == DT_OP_NOP || ip[0] == DT_OP_RET) + return (0); + + /* + * We only expect call instructions with a displacement of 0, or a jump + * instruction acting as a tail call. + */ + if (ip[0] != DT_OP_CALL26 && ip[0] != DT_OP_JUMP26) { + dt_dprintf("found %x instead of a call or jmp instruction at " + "%llx\n", ip[0], (u_longlong_t)rela->r_offset); + return (-1); + } + + /* + * On arm64, we do not have to differentiate between regular probes and + * is-enabled probes. Both cases are encoded as a regular branch for + * non-tail call locations, and a jump for tail call locations. Calls + * are to be converted into a no-op whereas jumps should become a + * return. + */ + if (ip[0] == DT_OP_CALL26) + ip[0] = DT_OP_NOP; + else + ip[0] = DT_OP_RET; + + return (0); +} +#elif defined(__arm__) +#define DT_REL_NONE R_ARM_NONE + +static int +dt_modtext(dtrace_hdl_t *dtp, char *p, int isenabled, GElf_Rela *rela, + uint32_t *off) +{ + printf("%s:%s(%d): arm not implemented\n", __FUNCTION__, __FILE__, + __LINE__); + return (-1); +} +#elif defined(__powerpc__) +/* The sentinel is 'xor r3,r3,r3'. */ +#define DT_OP_XOR_R3 0x7c631a78 + +#define DT_OP_NOP 0x60000000 +#define DT_OP_BLR 0x4e800020 + +/* This captures all forms of branching to address. */ +#define DT_IS_BRANCH(inst) ((inst & 0xfc000000) == 0x48000000) +#define DT_IS_BL(inst) (DT_IS_BRANCH(inst) && (inst & 0x01)) + +#define DT_REL_NONE R_PPC_NONE + +static int +dt_modtext(dtrace_hdl_t *dtp, char *p, int isenabled, 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_PPC_REL24 && + GELF_R_TYPE(rela->r_info) != R_PPC_PLTREL24 && + GELF_R_TYPE(rela->r_info) != R_PPC_NONE) + return (-1); + + /* + * We may have already processed this object file in an earlier linker + * invocation. Check to see if the present instruction sequence matches + * the one we would install below. + */ + if (isenabled) { + if (ip[0] == DT_OP_XOR_R3) { + (*off) += sizeof (ip[0]); + return (0); + } + } else { + if (ip[0] == DT_OP_NOP) { + (*off) += sizeof (ip[0]); + return (0); + } + } + + /* + * We only expect branch to address instructions. + */ + if (!DT_IS_BRANCH(ip[0])) { + dt_dprintf("found %x instead of a branch instruction at %llx\n", + ip[0], (u_longlong_t)rela->r_offset); + return (-1); + } + + if (isenabled) { + /* + * It would necessarily indicate incorrect usage if an is- + * enabled probe were tail-called so flag that as an error. + * It's also potentially (very) tricky to handle gracefully, + * but could be done if this were a desired use scenario. + */ + if (!DT_IS_BL(ip[0])) { + dt_dprintf("tail call to is-enabled probe at %llx\n", + (u_longlong_t)rela->r_offset); + return (-1); + } + + ip[0] = DT_OP_XOR_R3; + (*off) += sizeof (ip[0]); + } else { + if (DT_IS_BL(ip[0])) + ip[0] = DT_OP_NOP; + else + ip[0] = DT_OP_BLR; + } + + return (0); +} +#elif defined(__riscv) +#define DT_OP_NOP 0x00000013 /* addi x0, x0, 0 */ +#define DT_OP_RET 0x00008067 /* jalr x0, x1, 0 */ +#define DT_OP_IS_AUIPC(op) (((op) & 0x7f) == 0x17) +#define DT_OP_IS_JALR(op) (((op) & 0x707f) == 0x67) +#define DT_OP_JALR_CALL 0x000080e7 /* jalr x1, x1, 0 */ +#define DT_OP_JALR_TAIL 0x00030067 /* jalr x0, x6, 0 */ +#define DT_REL_NONE R_RISCV_NONE + +static int +dt_modtext(dtrace_hdl_t *dtp, char *p, int isenabled, GElf_Rela *rela, + uint32_t *off) +{ + uint32_t *ip; + + /* + * XXX: this implementation is untested, but should serve as a decent + * starting point. + */ + + /* + * Ensure that the offset is aligned on a compressed-instruction + * boundary. + */ + if ((rela->r_offset & (sizeof (uint16_t) - 1)) != 0) + return (-1); + + /* + * We only know about some specific relocation types. + * We also recognize relocation type NONE, since that gets used for + * relocations of USDT probes, and we might be re-processing a file. + */ + if (GELF_R_TYPE(rela->r_info) != R_RISCV_CALL && + GELF_R_TYPE(rela->r_info) != R_RISCV_CALL_PLT && + GELF_R_TYPE(rela->r_info) != R_RISCV_NONE) + return (-1); + + ip = (uint32_t *)(p + rela->r_offset); + + /* + * We may have already processed this object file in an earlier linker + * invocation. Check to see if the present instruction sequence matches + * the one we would install below. + */ + if (ip[0] == DT_OP_NOP && (ip[1] == DT_OP_NOP || ip[1] == DT_OP_RET)) + return (0); + + /* + * We expect a auipc+jalr pair, either from a call or a tail. + * - call: auipc x1 0; jalr x1, x1, 0 + * - tail: auipc x6 0; jalr x0, x6, 0 + */ + if (!DT_OP_IS_AUIPC(ip[0]) || !DT_OP_IS_JALR(ip[1])) + return (-1); + + /* + * On riscv, we do not have to differentiate between regular probes and + * is-enabled probes. Calls are to be converted into a no-op whereas + * tail calls should become a return. + */ + if (ip[1] == DT_OP_JALR_CALL) { + ip[0] = DT_OP_NOP; + ip[1] = DT_OP_NOP; + } else { + ip[0] = DT_OP_NOP; + ip[1] = DT_OP_RET; + } + + return (0); +} + +#elif defined(__i386) || defined(__amd64) + +#define DT_OP_NOP 0x90 +#define DT_OP_RET 0xc3 +#define DT_OP_CALL 0xe8 +#define DT_OP_JMP32 0xe9 +#define DT_OP_REX_RAX 0x48 +#define DT_OP_XOR_EAX_0 0x33 +#define DT_OP_XOR_EAX_1 0xc0 + +#define DT_REL_NONE R_386_NONE + +static int +dt_modtext(dtrace_hdl_t *dtp, char *p, int isenabled, GElf_Rela *rela, + uint32_t *off) +{ + uint8_t *ip = (uint8_t *)(p + rela->r_offset - 1); + uint8_t ret; + + /* + * 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 operand. We back up the offset to the first byte of + * the instruction. For is-enabled probes, we later advance the offset + * so that it hits the first nop in the instruction sequence. + */ + (*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 && + GELF_R_TYPE(rela->r_info) != R_386_NONE) + return (-1); + + /* + * We may have already processed this object file in an earlier linker + * invocation. Check to see if the present instruction sequence matches + * the one we would install. For is-enabled probes, we advance the + * offset to the first nop instruction in the sequence to match the + * text modification code below. + */ + if (!isenabled) { + if ((ip[0] == DT_OP_NOP || ip[0] == DT_OP_RET) && + ip[1] == DT_OP_NOP && ip[2] == DT_OP_NOP && + ip[3] == DT_OP_NOP && ip[4] == DT_OP_NOP) + return (0); + } else if (dtp->dt_oflags & DTRACE_O_LP64) { + if (ip[0] == DT_OP_REX_RAX && + ip[1] == DT_OP_XOR_EAX_0 && ip[2] == DT_OP_XOR_EAX_1 && + (ip[3] == DT_OP_NOP || ip[3] == DT_OP_RET) && + ip[4] == DT_OP_NOP) { + (*off) += 3; + return (0); + } + } else { + if (ip[0] == DT_OP_XOR_EAX_0 && ip[1] == DT_OP_XOR_EAX_1 && + (ip[2] == DT_OP_NOP || ip[2] == DT_OP_RET) && + ip[3] == DT_OP_NOP && ip[4] == DT_OP_NOP) { + (*off) += 2; + return (0); + } + } + + /* + * We expect either a call instrution with a 32-bit displacement or a + * jmp instruction with a 32-bit displacement acting as a tail-call. + */ + if (ip[0] != DT_OP_CALL && ip[0] != DT_OP_JMP32) { + dt_dprintf("found %x instead of a call or jmp instruction at " + "%llx\n", ip[0], (u_longlong_t)rela->r_offset); + return (-1); + } + + ret = (ip[0] == DT_OP_JMP32) ? DT_OP_RET : DT_OP_NOP; + + /* + * Establish the instruction sequence -- all nops for probes, and an + * instruction to clear the return value register (%eax/%rax) followed + * by nops for is-enabled probes. For is-enabled probes, we advance + * the offset to the first nop. This isn't stricly necessary but makes + * for more readable disassembly when the probe is enabled. + */ + if (!isenabled) { + ip[0] = ret; + ip[1] = DT_OP_NOP; + ip[2] = DT_OP_NOP; + ip[3] = DT_OP_NOP; + ip[4] = DT_OP_NOP; + } else if (dtp->dt_oflags & DTRACE_O_LP64) { + ip[0] = DT_OP_REX_RAX; + ip[1] = DT_OP_XOR_EAX_0; + ip[2] = DT_OP_XOR_EAX_1; + ip[3] = ret; + ip[4] = DT_OP_NOP; + (*off) += 3; + } else { + ip[0] = DT_OP_XOR_EAX_0; + ip[1] = DT_OP_XOR_EAX_1; + ip[2] = ret; + ip[3] = DT_OP_NOP; + ip[4] = DT_OP_NOP; + (*off) += 2; + } + + return (0); +} + +#else +#error unknown ISA +#endif + +/*PRINTFLIKE5*/ +static int +dt_link_error(dtrace_hdl_t *dtp, Elf *elf, int fd, dt_link_pair_t *bufs, + const char *format, ...) +{ + va_list ap; + dt_link_pair_t *pair; + + va_start(ap, format); + dt_set_errmsg(dtp, NULL, NULL, NULL, 0, format, ap); + va_end(ap); + + if (elf != NULL) + (void) elf_end(elf); + + if (fd >= 0) + (void) close(fd); + + while ((pair = bufs) != NULL) { + bufs = pair->dlp_next; + dt_free(dtp, pair->dlp_str); + dt_free(dtp, pair->dlp_sym); + dt_free(dtp, pair); + } + + return (dt_set_errno(dtp, EDT_COMPILER)); +} + +/* + * Provide a unique identifier used when adding global symbols to an object. + * This is the FNV-1a hash of an absolute path for the file. + */ +static unsigned int +hash_obj(const char *obj, int fd) +{ + char path[PATH_MAX]; + unsigned int h; + + if (realpath(obj, path) == NULL) + return (-1); + + for (h = 2166136261u, obj = &path[0]; *obj != '\0'; obj++) + h = (h ^ *obj) * 16777619; + h &= 0x7fffffff; + return (h); +} + +static int +process_obj(dtrace_hdl_t *dtp, const char *obj, int *eprobesp) +{ + static const char dt_prefix[] = "__dtrace"; + static const char dt_enabled[] = "enabled"; + static const char dt_symprefix[] = "$dtrace"; + static const char dt_symfmt[] = "%s%u.%s"; + static const char dt_weaksymfmt[] = "%s.%s"; + char probename[DTRACE_NAMELEN]; + int fd, i, ndx, eprobe, uses_funcdesc = 0, mod = 0; + Elf *elf = NULL; + GElf_Ehdr ehdr; + Elf_Scn *scn_rel, *scn_sym, *scn_str, *scn_tgt; + Elf_Data *data_rel, *data_sym, *data_str, *data_tgt; + GElf_Shdr shdr_rel, shdr_sym, shdr_str, shdr_tgt; + GElf_Sym rsym, fsym, dsym; + GElf_Rela rela; + char *s, *p, *r; + char pname[DTRACE_PROVNAMELEN]; + dt_provider_t *pvp; + dt_probe_t *prp; + uint32_t off, eclass, emachine1, emachine2; + size_t symsize, osym, nsym, isym, istr, len; + unsigned int objkey; + dt_link_pair_t *pair, *bufs = NULL; + dt_strtab_t *strtab; + void *tmp; + + if ((fd = open64(obj, O_RDWR)) == -1) { + return (dt_link_error(dtp, elf, fd, bufs, + "failed to open %s: %s", obj, strerror(errno))); + } + + if ((elf = elf_begin(fd, ELF_C_RDWR, NULL)) == NULL) { + return (dt_link_error(dtp, elf, fd, bufs, + "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, elf, fd, bufs, "archives are not " + "permitted; use the contents of the archive instead: %s", + obj)); + default: + return (dt_link_error(dtp, elf, fd, bufs, + "invalid file type: %s", obj)); + } + + if (gelf_getehdr(elf, &ehdr) == NULL) { + return (dt_link_error(dtp, elf, fd, bufs, "corrupt file: %s", + obj)); + } + + if (dtp->dt_oflags & DTRACE_O_LP64) { + eclass = ELFCLASS64; +#if defined(__powerpc__) + emachine1 = emachine2 = EM_PPC64; +#if !defined(_CALL_ELF) || _CALL_ELF == 1 + uses_funcdesc = 1; +#endif +#elif defined(__i386) || defined(__amd64) + emachine1 = emachine2 = EM_AMD64; +#elif defined(__aarch64__) + emachine1 = emachine2 = EM_AARCH64; +#elif defined(__riscv) + emachine1 = emachine2 = EM_RISCV; +#endif + symsize = sizeof (Elf64_Sym); + } else { + eclass = ELFCLASS32; +#if defined(__arm__) + emachine1 = emachine2 = EM_ARM; +#elif defined(__powerpc__) + emachine1 = emachine2 = EM_PPC; +#elif defined(__i386) || defined(__amd64) + emachine1 = emachine2 = EM_386; +#endif + symsize = sizeof (Elf32_Sym); + } + + if (ehdr.e_ident[EI_CLASS] != eclass) { + return (dt_link_error(dtp, elf, fd, bufs, + "incorrect ELF class for object file: %s", obj)); + } + + if (ehdr.e_machine != emachine1 && ehdr.e_machine != emachine2) { + return (dt_link_error(dtp, elf, fd, bufs, + "incorrect ELF machine type for object file: %s", obj)); + } + + /* + * We use this token as a relatively unique handle for this file on the + * system in order to disambiguate potential conflicts between files of + * the same name which contain identially named local symbols. + */ + if ((objkey = hash_obj(obj, fd)) == (unsigned int)-1) + return (dt_link_error(dtp, elf, fd, bufs, + "failed to generate unique key 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; + + /* + * Skip any non-relocation sections. + */ + 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; + + /* + * Grab the section, section header and section data for the + * symbol table that this relocation section references. + */ + 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; + + /* + * Ditto for that symbol table's string table. + */ + if ((scn_str = elf_getscn(elf, shdr_sym.sh_link)) == NULL || + gelf_getshdr(scn_str, &shdr_str) == NULL || + (data_str = elf_getdata(scn_str, NULL)) == NULL) + goto err; + + /* + * Grab the section, section header and section data for the + * target section for the relocations. For the relocations + * we're looking for -- this will typically be the text of the + * object file. + */ + 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; + + /* + * We're looking for relocations to symbols matching this form: + * + * __dtrace[enabled]_<prov>___<probe> + * + * For the generated object, we need to record the location + * identified by the relocation, and create a new relocation + * in the generated object that will be resolved at link time + * to the location of the function in which the probe is + * embedded. In the target object, we change the matched symbol + * so that it will be ignored at link time, and we modify the + * target (text) section to replace the call instruction with + * one or more nops. + * + * To avoid runtime overhead, the relocations added to the + * generated object should be resolved at static link time. We + * therefore create aliases for the functions that contain + * probes. An alias is global (so that the relocation from the + * generated object can be resolved), and hidden (so that its + * address is known at static link time). Such aliases have this + * form: + * + * $dtrace<key>.<function> + * + * We take a first pass through all the relocations to + * populate our string table and count the number of extra + * symbols we'll require. + * + * We also handle the case where the object has already been + * processed, to support incremental rebuilds. Relocations + * of interest are converted to type NONE, but all information + * needed to reconstruct the output DOF is retained. + */ + strtab = dt_strtab_create(1); + nsym = 0; + isym = data_sym->d_size / symsize; + istr = data_str->d_size; + + 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 { + GElf_Rel rel; + 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; + } + + if (gelf_getsym(data_sym, GELF_R_SYM(rela.r_info), + &rsym) == NULL) { + dt_strtab_destroy(strtab); + goto err; + } + + s = (char *)data_str->d_buf + rsym.st_name; + + if (strncmp(s, dt_prefix, sizeof (dt_prefix) - 1) != 0) + continue; + + if (dt_symtab_lookup(data_sym, 0, isym, rela.r_offset, + shdr_rel.sh_info, &fsym, uses_funcdesc, + elf) != 0) { + dt_strtab_destroy(strtab); + goto err; + } + + if (fsym.st_name > data_str->d_size) { + dt_strtab_destroy(strtab); + goto err; + } + + s = (char *)data_str->d_buf + fsym.st_name; + + /* + * If this symbol isn't of type function, we've really + * driven off the rails or the object file is corrupt. + */ + if (GELF_ST_TYPE(fsym.st_info) != STT_FUNC) { + dt_strtab_destroy(strtab); + return (dt_link_error(dtp, elf, fd, bufs, + "expected %s to be of type function", s)); + } + + /* + * Aliases of weak symbols don't get a uniquifier. + */ + if (GELF_ST_BIND(fsym.st_info) == STB_WEAK) { + len = snprintf(NULL, 0, dt_weaksymfmt, + dt_symprefix, s) + 1; + } else { + len = snprintf(NULL, 0, dt_symfmt, dt_symprefix, + objkey, s) + 1; + } + if ((p = dt_alloc(dtp, len)) == NULL) { + dt_strtab_destroy(strtab); + goto err; + } + if (GELF_ST_BIND(fsym.st_info) == STB_WEAK) { + (void) snprintf(p, len, dt_weaksymfmt, + dt_symprefix, s); + } else { + (void) snprintf(p, len, dt_symfmt, dt_symprefix, + objkey, s); + } + + if (dt_strtab_index(strtab, p) == -1) { + /* + * Do not add new symbols if this object file + * has already been processed. + */ + if (GELF_R_TYPE(rela.r_info) != DT_REL_NONE) + nsym++; + (void) dt_strtab_insert(strtab, p); + } + + dt_free(dtp, p); + } + + /* + * If any new probes were found, allocate the additional space + * for the symbol table and string table, copying the old data + * into the new buffers, and marking the buffers as dirty. We + * inject those newly allocated buffers into the libelf data + * structures, but are still responsible for freeing them once + * we're done with the elf handle. + */ + osym = isym; + if (nsym > 0) { + /* + * The first byte of the string table is reserved for + * the \0 entry. + */ + len = dt_strtab_size(strtab) - 1; + + assert(len > 0); + assert(dt_strtab_index(strtab, "") == 0); + + dt_strtab_destroy(strtab); + + if ((pair = dt_alloc(dtp, sizeof (*pair))) == NULL) + goto err; + + if ((pair->dlp_str = dt_alloc(dtp, data_str->d_size + + len)) == NULL) { + dt_free(dtp, pair); + goto err; + } + + if ((pair->dlp_sym = dt_alloc(dtp, data_sym->d_size + + nsym * symsize)) == NULL) { + dt_free(dtp, pair->dlp_str); + dt_free(dtp, pair); + goto err; + } + + pair->dlp_next = bufs; + bufs = pair; + + bcopy(data_str->d_buf, pair->dlp_str, data_str->d_size); + tmp = data_str->d_buf; + data_str->d_buf = pair->dlp_str; + pair->dlp_str = tmp; + data_str->d_size += len; + (void) elf_flagdata(data_str, ELF_C_SET, ELF_F_DIRTY); + + shdr_str.sh_size += len; + (void) gelf_update_shdr(scn_str, &shdr_str); + + bcopy(data_sym->d_buf, pair->dlp_sym, data_sym->d_size); + tmp = data_sym->d_buf; + data_sym->d_buf = pair->dlp_sym; + pair->dlp_sym = tmp; + data_sym->d_size += nsym * symsize; + (void) elf_flagdata(data_sym, ELF_C_SET, ELF_F_DIRTY); + + shdr_sym.sh_size += nsym * symsize; + (void) gelf_update_shdr(scn_sym, &shdr_sym); + + nsym += isym; + } else if (dt_strtab_empty(strtab)) { + dt_strtab_destroy(strtab); + continue; + } + + /* + * Now that the tables have been allocated, perform the + * modifications described above. + */ + 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 { + GElf_Rel rel; + 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 || + rsym.st_name > data_str->d_size) + goto err; + + s = (char *)data_str->d_buf + rsym.st_name; + + if (strncmp(s, dt_prefix, sizeof (dt_prefix) - 1) != 0) + continue; + + s += sizeof (dt_prefix) - 1; + + /* + * Check to see if this is an 'is-enabled' check as + * opposed to a normal probe. + */ + if (strncmp(s, dt_enabled, + sizeof (dt_enabled) - 1) == 0) { + s += sizeof (dt_enabled) - 1; + eprobe = 1; + *eprobesp = 1; + dt_dprintf("is-enabled probe\n"); + } else { + eprobe = 0; + dt_dprintf("normal probe\n"); + } + + if (*s++ != '_') + goto err; + + if ((p = strstr(s, "___")) == NULL || + p - s >= sizeof (pname)) + goto err; + + bcopy(s, pname, p - s); + pname[p - s] = '\0'; + + if (dt_symtab_lookup(data_sym, osym, isym, + rela.r_offset, shdr_rel.sh_info, &fsym, + uses_funcdesc, elf) == 0) { + if (fsym.st_name > data_str->d_size) + goto err; + + r = s = (char *) data_str->d_buf + fsym.st_name; + assert(strstr(s, dt_symprefix) == s); + s = strchr(s, '.') + 1; + } else if (dt_symtab_lookup(data_sym, 0, osym, + rela.r_offset, shdr_rel.sh_info, &fsym, + uses_funcdesc, elf) == 0) { + u_int bind; + + bind = GELF_ST_BIND(fsym.st_info) == STB_WEAK ? + STB_WEAK : STB_GLOBAL; + s = (char *) data_str->d_buf + fsym.st_name; + if (GELF_R_TYPE(rela.r_info) != DT_REL_NONE) { + /* + * Emit an alias for the symbol. It + * needs to be non-preemptible so that + * .SUNW_dof relocations may be resolved + * at static link time. Aliases of weak + * symbols are given a non-unique name + * so that they may be merged by the + * linker. + */ + dsym = fsym; + dsym.st_name = istr; + dsym.st_info = GELF_ST_INFO(bind, + STT_FUNC); + dsym.st_other = + GELF_ST_VISIBILITY(STV_HIDDEN); + (void) gelf_update_sym(data_sym, isym, + &dsym); + isym++; + assert(isym <= nsym); + + r = (char *) data_str->d_buf + istr; + if (bind == STB_WEAK) { + istr += sprintf(r, + dt_weaksymfmt, dt_symprefix, + s); + } else { + istr += sprintf(r, dt_symfmt, + dt_symprefix, objkey, s); + } + istr++; + } else { + if (bind == STB_WEAK) { + (void) asprintf(&r, + dt_weaksymfmt, dt_symprefix, + s); + } else { + (void) asprintf(&r, dt_symfmt, + dt_symprefix, objkey, s); + } + } + } else { + goto err; + } + + if ((pvp = dt_provider_lookup(dtp, pname)) == NULL) { + return (dt_link_error(dtp, elf, fd, bufs, + "no such provider %s", pname)); + } + + if (strlcpy(probename, p + 3, sizeof (probename)) >= + sizeof (probename)) + return (dt_link_error(dtp, elf, fd, bufs, + "invalid probe name %s", probename)); + (void) strhyphenate(probename); + if ((prp = dt_probe_lookup(pvp, probename)) == NULL) + return (dt_link_error(dtp, elf, fd, bufs, + "no such probe %s", probename)); + + assert(fsym.st_value <= rela.r_offset); + + off = rela.r_offset - fsym.st_value; + if (dt_modtext(dtp, data_tgt->d_buf, eprobe, + &rela, &off) != 0) + goto err; + + if (dt_probe_define(pvp, prp, s, r, off, eprobe) != 0) { + return (dt_link_error(dtp, elf, fd, bufs, + "failed to allocate space for probe")); + } + + /* + * We are done with this relocation, but it must be + * preserved in order to support incremental rebuilds. + */ + if (shdr_rel.sh_type == SHT_RELA) { + rela.r_info = GELF_R_INFO( + GELF_R_SYM(rela.r_info), DT_REL_NONE); + (void) gelf_update_rela(data_rel, i, &rela); + } else { + GElf_Rel rel; + rel.r_offset = rela.r_offset; + rel.r_info = GELF_R_INFO( + GELF_R_SYM(rela.r_info), DT_REL_NONE); + (void) gelf_update_rel(data_rel, i, &rel); + } + + mod = 1; + (void) elf_flagdata(data_tgt, ELF_C_SET, ELF_F_DIRTY); + + /* + * 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_ABS) { + rsym.st_info = GELF_ST_INFO(STB_WEAK, STT_FUNC); + rsym.st_shndx = SHN_ABS; + (void) gelf_update_sym(data_sym, ndx, &rsym); + } + } + } + + if (mod && elf_update(elf, ELF_C_WRITE) == -1) + goto err; + + (void) elf_end(elf); + (void) close(fd); + + while ((pair = bufs) != NULL) { + bufs = pair->dlp_next; + dt_free(dtp, pair->dlp_str); + dt_free(dtp, pair->dlp_sym); + dt_free(dtp, pair); + } + + return (0); + +err: + return (dt_link_error(dtp, elf, fd, bufs, + "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 tfile[PATH_MAX]; + char drti[PATH_MAX]; + dof_hdr_t *dof; + int fd, status, i, cur; + char *cmd, tmp; + size_t len; + int eprobes = 0, ret = 0; + + /* + * A NULL program indicates a special use in which we just link + * together a bunch of object files specified in objv and then + * unlink(2) those object files. + */ + if (pgp == NULL) { + const char *fmt = "%s -o %s -r"; + + len = snprintf(&tmp, 1, fmt, dtp->dt_ld_path, file) + 1; + + for (i = 0; i < objc; i++) + len += strlen(objv[i]) + 1; + + cmd = alloca(len); + + cur = snprintf(cmd, len, fmt, dtp->dt_ld_path, file); + + for (i = 0; i < objc; i++) + cur += snprintf(cmd + cur, len - cur, " %s", objv[i]); + + if ((status = system(cmd)) == -1) { + return (dt_link_error(dtp, NULL, -1, NULL, + "failed to run %s: %s", dtp->dt_ld_path, + strerror(errno))); + } + + if (WIFSIGNALED(status)) { + return (dt_link_error(dtp, NULL, -1, NULL, + "failed to link %s: %s failed due to signal %d", + file, dtp->dt_ld_path, WTERMSIG(status))); + } + + if (WEXITSTATUS(status) != 0) { + return (dt_link_error(dtp, NULL, -1, NULL, + "failed to link %s: %s exited with status %d\n", + file, dtp->dt_ld_path, WEXITSTATUS(status))); + } + + for (i = 0; i < objc; i++) { + if (strcmp(objv[i], file) != 0) + (void) unlink(objv[i]); + } + + return (0); + } + + for (i = 0; i < objc; i++) { + if (process_obj(dtp, objv[i], &eprobes) != 0) + return (-1); /* errno is set for us */ + } + + /* + * If there are is-enabled probes then we need to force use of DOF + * version 2. + */ + if (eprobes && pgp->dp_dofversion < DOF_VERSION_2) + pgp->dp_dofversion = DOF_VERSION_2; + + if ((dof = dtrace_dof_create(dtp, pgp, dflags)) == NULL) + return (-1); /* errno is set for us */ + + snprintf(tfile, sizeof(tfile), "%s.XXXXXX", file); + if ((fd = mkostemp(tfile, O_CLOEXEC)) == -1) + return (dt_link_error(dtp, NULL, -1, NULL, + "failed to create temporary file %s: %s", + tfile, 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, NULL, -1, NULL, + "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, NULL, -1, NULL, + "invalid link type %u\n", dtp->dt_linktype)); + } + + + if (dtp->dt_oflags & DTRACE_O_LP64) + status = dump_elf64(dtp, dof, fd); + else + status = dump_elf32(dtp, dof, fd); + + if (status != 0) + return (dt_link_error(dtp, NULL, -1, NULL, + "failed to write %s: %s", tfile, + strerror(dtrace_errno(dtp)))); + + if (!dtp->dt_lazyload) { + const char *fmt = "%s -o %s -r %s %s"; + dt_dirpath_t *dp = dt_list_next(&dtp->dt_lib_path); + + (void) snprintf(drti, sizeof (drti), "%s/drti.o", dp->dir_path); + + len = snprintf(&tmp, 1, fmt, dtp->dt_ld_path, file, tfile, + drti) + 1; + + cmd = alloca(len); + + (void) snprintf(cmd, len, fmt, dtp->dt_ld_path, file, tfile, + drti); + if ((status = system(cmd)) == -1) { + ret = dt_link_error(dtp, NULL, fd, NULL, + "failed to run %s: %s", dtp->dt_ld_path, + strerror(errno)); + goto done; + } + + if (WIFSIGNALED(status)) { + ret = dt_link_error(dtp, NULL, fd, NULL, + "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, NULL, fd, NULL, + "failed to link %s: %s exited with status %d\n", + file, dtp->dt_ld_path, WEXITSTATUS(status)); + goto done; + } + (void) close(fd); /* release temporary file */ + + /* + * Now that we've linked drti.o, reduce the global __SUNW_dof + * symbol to a local symbol. This is needed to so that multiple + * generated object files (for different providers, for + * instance) can be linked together. This is accomplished using + * the -Blocal flag with Sun's linker, but GNU ld doesn't appear + * to have an equivalent option. + */ + asprintf(&cmd, "%s --localize-hidden %s", dtp->dt_objcopy_path, + file); + if ((status = system(cmd)) == -1) { + ret = dt_link_error(dtp, NULL, -1, NULL, + "failed to run %s: %s", dtp->dt_objcopy_path, + strerror(errno)); + free(cmd); + goto done; + } + free(cmd); + + if (WIFSIGNALED(status)) { + ret = dt_link_error(dtp, NULL, -1, NULL, + "failed to link %s: %s failed due to signal %d", + file, dtp->dt_objcopy_path, WTERMSIG(status)); + goto done; + } + + if (WEXITSTATUS(status) != 0) { + ret = dt_link_error(dtp, NULL, -1, NULL, + "failed to link %s: %s exited with status %d\n", + file, dtp->dt_objcopy_path, WEXITSTATUS(status)); + goto done; + } + } else { + if (rename(tfile, file) != 0) { + ret = dt_link_error(dtp, NULL, fd, NULL, + "failed to rename %s to %s: %s", tfile, file, + strerror(errno)); + goto done; + } + (void) close(fd); + } + +done: + dtrace_dof_destroy(dtp, dof); + + if (!dtp->dt_lazyload) + (void) unlink(tfile); + return (ret); +} |