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authorJohn Birrell <jb@FreeBSD.org>2008-04-25 09:04:09 +0000
committerJohn Birrell <jb@FreeBSD.org>2008-04-25 09:04:09 +0000
commitc53d354ffe3b3f603cf36c67c489eeeb881403b2 (patch)
treec9428b1eda7cd726730c2a51001d1afaee07c0e6 /lib/libdtrace/common/dt_link.c
parent12456ea875a4e2a468753b9890e6864519aeb931 (diff)
downloadsrc-c53d354ffe3b3f603cf36c67c489eeeb881403b2.tar.gz
src-c53d354ffe3b3f603cf36c67c489eeeb881403b2.zip
Vendor import of libraries for DTrace from OpenSolaris.
Notes
Notes: svn path=/vendor-cddl/opensolaris/dist/cddl/contrib/opensolaris/; revision=178479
Diffstat (limited to 'lib/libdtrace/common/dt_link.c')
-rw-r--r--lib/libdtrace/common/dt_link.c1774
1 files changed, 1774 insertions, 0 deletions
diff --git a/lib/libdtrace/common/dt_link.c b/lib/libdtrace/common/dt_link.c
new file mode 100644
index 000000000000..bc46df577a27
--- /dev/null
+++ b/lib/libdtrace/common/dt_link.c
@@ -0,0 +1,1774 @@
+/*
+ * 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.
+ */
+
+#pragma ident "%Z%%M% %I% %E% SMI"
+
+#define ELF_TARGET_ALL
+#include <elf.h>
+
+#include <sys/types.h>
+#if defined(sun)
+#include <sys/sysmacros.h>
+#else
+#define P2ROUNDUP(x, align) (-(-(x) & -(align)))
+#endif
+
+#include <unistd.h>
+#include <strings.h>
+#if defined(sun)
+#include <alloca.h>
+#endif
+#include <limits.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <errno.h>
+#if defined(sun)
+#include <wait.h>
+#else
+#include <sys/wait.h>
+#endif
+#include <assert.h>
+#include <sys/ipc.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 */
+#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 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 */
+#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(__arm__)
+/* XXX */
+printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
+#elif defined(__ia64__)
+/* XXX */
+printf("%s:%s(%d): DOODAD\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_32);
+#elif defined(__mips__)
+/* XXX */
+printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
+#elif defined(__powerpc__)
+/* XXX */
+printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
+#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_FUNC);
+ 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++) {
+printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
+#ifdef DOODAD
+#if defined(__arm__)
+/* XXX */
+#elif defined(__ia64__)
+/* XXX */
+#elif defined(__mips__)
+/* XXX */
+#elif defined(__powerpc__)
+/* XXX */
+#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_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
+#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 = 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 = GELF_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 BYTE_ORDER == _BIG_ENDIAN
+ elf_file.ehdr.e_ident[EI_DATA] = ELFDATA2MSB;
+#else
+ elf_file.ehdr.e_ident[EI_DATA] = ELFDATA2LSB;
+#endif
+#if defined(__FreeBSD__)
+ elf_file.ehdr.e_ident[EI_OSABI] = ELFOSABI_FREEBSD;
+#endif
+ elf_file.ehdr.e_type = ET_REL;
+#if defined(__arm__)
+ elf_file.ehdr.e_machine = EM_ARM;
+#elif defined(__ia64__)
+ elf_file.ehdr.e_machine = EM_IA_64;
+#elif defined(__mips__)
+ elf_file.ehdr.e_machine = EM_MIPS;
+#elif defined(__powerpc__)
+ elf_file.ehdr.e_machine = EM_PPC;
+#elif 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 BYTE_ORDER == _BIG_ENDIAN
+ elf_file.ehdr.e_ident[EI_DATA] = ELFDATA2MSB;
+#else
+ elf_file.ehdr.e_ident[EI_DATA] = ELFDATA2LSB;
+#endif
+#if defined(__FreeBSD__)
+ elf_file.ehdr.e_ident[EI_OSABI] = ELFOSABI_FREEBSD;
+#endif
+ elf_file.ehdr.e_type = ET_REL;
+#if defined(__arm__)
+ elf_file.ehdr.e_machine = EM_ARM;
+#elif defined(__ia64__)
+ elf_file.ehdr.e_machine = EM_IA_64;
+#elif defined(__mips__)
+ elf_file.ehdr.e_machine = EM_MIPS;
+#elif defined(__powerpc__)
+ elf_file.ehdr.e_machine = EM_PPC;
+#elif 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, int nsym, uintptr_t addr, uint_t shn,
+ GElf_Sym *sym)
+{
+ int i, ret = -1;
+ GElf_Sym s;
+
+ for (i = 0; i < nsym && 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(__arm__)
+/* XXX */
+static int
+dt_modtext(dtrace_hdl_t *dtp, char *p, int isenabled, GElf_Rela *rela,
+ uint32_t *off)
+{
+printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
+ return (0);
+}
+#elif defined(__ia64__)
+/* XXX */
+static int
+dt_modtext(dtrace_hdl_t *dtp, char *p, int isenabled, GElf_Rela *rela,
+ uint32_t *off)
+{
+printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
+ return (0);
+}
+#elif defined(__mips__)
+/* XXX */
+static int
+dt_modtext(dtrace_hdl_t *dtp, char *p, int isenabled, GElf_Rela *rela,
+ uint32_t *off)
+{
+printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
+ return (0);
+}
+#elif defined(__powerpc__)
+/* XXX */
+static int
+dt_modtext(dtrace_hdl_t *dtp, char *p, int isenabled, GElf_Rela *rela,
+ uint32_t *off)
+{
+printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
+ return (0);
+}
+
+#elif defined(__sparc)
+
+#define DT_OP_RET 0x81c7e008
+#define DT_OP_NOP 0x01000000
+#define DT_OP_CALL 0x40000000
+#define DT_OP_CLR_O0 0x90102000
+
+#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))
+
+/*ARGSUSED*/
+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_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. Check to see if the present instruction sequence matches
+ * the one we would install.
+ */
+ if (isenabled) {
+ if (ip[0] == DT_OP_CLR_O0)
+ return (0);
+ } else {
+ 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 (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_RESTORE(ip[1]) || DT_IS_MOV_O7(ip[1])) {
+ dt_dprintf("tail call to is-enabled probe at %llx\n",
+ (u_longlong_t)rela->r_offset);
+ return (-1);
+ }
+
+ ip[0] = DT_OP_CLR_O0;
+ } else {
+ /*
+ * 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); the delay slot instruction is left, but should have no
+ * effect. Otherwise we change the call to be a nop. In the
+ * first and the last case we adjust the offset to land on what
+ * was once the delay slot of the call so we correctly get all
+ * the arguments as they would have been passed in a normal
+ * function call.
+ */
+ if (DT_IS_RESTORE(ip[1])) {
+ ip[0] = DT_OP_RET;
+ (*off) += sizeof (ip[0]);
+ } 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_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
+
+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)
+ 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));
+}
+
+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%d.%s";
+ int fd, i, ndx, eprobe, 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, nsym, isym, istr, len;
+ key_t objkey;
+ dt_link_pair_t *pair, *bufs = NULL;
+ dt_strtab_t *strtab;
+
+ 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(__ia64__)
+ emachine1 = emachine2 = EM_IA_64;
+#elif defined(__mips__)
+ emachine1 = emachine2 = EM_MIPS;
+#elif defined(__powerpc__)
+ emachine1 = emachine2 = EM_PPC64;
+#elif defined(__sparc)
+ emachine1 = emachine2 = EM_SPARCV9;
+#elif defined(__i386) || defined(__amd64)
+ emachine1 = emachine2 = EM_AMD64;
+#endif
+ symsize = sizeof (Elf64_Sym);
+ } else {
+ eclass = ELFCLASS32;
+#if defined(__arm__)
+ emachine1 = emachine2 = EM_ARM;
+#elif defined(__mips__)
+ emachine1 = emachine2 = EM_MIPS;
+#elif defined(__powerpc__)
+ emachine1 = emachine2 = EM_PPC;
+#elif defined(__sparc)
+ emachine1 = EM_SPARC;
+ emachine2 = EM_SPARC32PLUS;
+#elif defined(__i386) || defined(__amd64) || defined(__ia64__)
+ 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 = ftok(obj, 0)) == (key_t)-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.
+ *
+ * If the function containing the probe is locally scoped
+ * (static), we create an alias used by the relocation in the
+ * generated object. The alias, a new symbol, will be global
+ * (so that the relocation from the generated object can be
+ * resolved), and hidden (so that it is converted to a local
+ * symbol at 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.
+ */
+ 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, isym, rela.r_offset,
+ shdr_rel.sh_info, &fsym) != 0) {
+ dt_strtab_destroy(strtab);
+ goto err;
+ }
+
+ if (GELF_ST_BIND(fsym.st_info) != STB_LOCAL)
+ continue;
+
+ 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));
+ }
+
+ len = snprintf(NULL, 0, dt_symfmt, dt_symprefix,
+ objkey, s) + 1;
+ if ((p = dt_alloc(dtp, len)) == NULL) {
+ dt_strtab_destroy(strtab);
+ goto err;
+ }
+ (void) snprintf(p, len, dt_symfmt, dt_symprefix,
+ objkey, s);
+
+ if (dt_strtab_index(strtab, p) == -1) {
+ nsym++;
+ (void) dt_strtab_insert(strtab, p);
+ }
+
+ dt_free(dtp, p);
+ }
+
+ /*
+ * If needed, 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.
+ */
+ 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);
+ data_str->d_buf = pair->dlp_str;
+ 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);
+ data_sym->d_buf = pair->dlp_sym;
+ 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 {
+ dt_strtab_destroy(strtab);
+ }
+
+ /*
+ * 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';
+
+ p = strhyphenate(p + 3); /* strlen("___") */
+
+ if (dt_symtab_lookup(data_sym, isym, rela.r_offset,
+ shdr_rel.sh_info, &fsym) != 0)
+ goto err;
+
+ if (fsym.st_name > data_str->d_size)
+ goto err;
+
+ assert(GELF_ST_TYPE(fsym.st_info) == STT_FUNC);
+
+ /*
+ * If a NULL relocation name is passed to
+ * dt_probe_define(), the function name is used for the
+ * relocation. The relocation needs to use a mangled
+ * name if the symbol is locally scoped; the function
+ * name may need to change if we've found the global
+ * alias for the locally scoped symbol (we prefer
+ * global symbols to locals in dt_symtab_lookup()).
+ */
+ s = (char *)data_str->d_buf + fsym.st_name;
+ r = NULL;
+
+ if (GELF_ST_BIND(fsym.st_info) == STB_LOCAL) {
+ dsym = fsym;
+ dsym.st_name = istr;
+ dsym.st_info = GELF_ST_INFO(STB_GLOBAL,
+ STT_FUNC);
+ dsym.st_other =
+ ELF64_ST_VISIBILITY(STV_ELIMINATE);
+ (void) gelf_update_sym(data_sym, isym, &dsym);
+
+ r = (char *)data_str->d_buf + istr;
+ istr += 1 + sprintf(r, dt_symfmt,
+ dt_symprefix, objkey, s);
+ isym++;
+ assert(isym <= nsym);
+
+ } else if (strncmp(s, dt_symprefix,
+ strlen(dt_symprefix)) == 0) {
+ r = s;
+ if ((s = strchr(s, '.')) == NULL)
+ goto err;
+ s++;
+ }
+
+ if ((pvp = dt_provider_lookup(dtp, pname)) == NULL) {
+ return (dt_link_error(dtp, elf, fd, bufs,
+ "no such provider %s", pname));
+ }
+
+ if ((prp = dt_probe_lookup(pvp, p)) == NULL) {
+ return (dt_link_error(dtp, elf, fd, bufs,
+ "no such probe %s", p));
+ }
+
+ 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"));
+ }
+
+ 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.
+ */
+printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
+#ifdef DOODAD
+ if (rsym.st_shndx != SHN_SUNW_IGNORE) {
+ rsym.st_shndx = SHN_SUNW_IGNORE;
+ (void) gelf_update_sym(data_sym, ndx, &rsym);
+ }
+#endif
+ }
+ }
+
+ 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[])
+{
+#if !defined(sun)
+ char tfile[PATH_MAX];
+#endif
+ char drti[PATH_MAX];
+ dof_hdr_t *dof;
+ int fd, status, i, cur;
+ char *cmd, tmp;
+ size_t len;
+ int eprobes = 0, ret = 0;
+
+#if !defined(sun)
+ /* XXX Should get a temp file name here. */
+ snprintf(tfile, sizeof(tfile), "%s.tmp", file);
+#endif
+
+ /*
+ * 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 */
+
+#if defined(sun)
+ /*
+ * 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, NULL, -1, NULL,
+ "failed to open %s: %s", file, strerror(errno)));
+ }
+#else
+ if ((fd = open(tfile, O_RDWR | O_CREAT | O_TRUNC, 0666)) == -1)
+ return (dt_link_error(dtp, NULL, -1, NULL,
+ "failed to open %s: %s", tfile, strerror(errno)));
+#endif
+
+ /*
+ * 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 defined(sun)
+ if (!dtp->dt_lazyload)
+ (void) unlink(file);
+#endif
+
+ 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, NULL, -1, NULL,
+ "failed to write %s: %s", file, strerror(errno)));
+ }
+
+ if (!dtp->dt_lazyload) {
+#if defined(sun)
+ const char *fmt = "%s -o %s -r -Blocal -Breduce /dev/fd/%d %s";
+
+ 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, fmt, dtp->dt_ld_path, file, fd,
+ drti) + 1;
+
+ cmd = alloca(len);
+
+ (void) snprintf(cmd, len, fmt, dtp->dt_ld_path, file, fd, drti);
+#else
+ const char *fmt = "%s -o %s -r %s %s";
+
+#if defined(__amd64__)
+ /*
+ * Arches which default to 64-bit need to explicitly use
+ * the 32-bit library path.
+ */
+ int use_32 = !(dtp->dt_oflags & DTRACE_O_LP64);
+#else
+ /*
+ * Arches which are 32-bit only just use the normal
+ * library path.
+ */
+#if defined(__i386__)
+ int use_32 = 1; /* use /usr/lib/... -sson */
+#else
+ int use_32 = 0;
+#endif
+#endif
+
+ (void) snprintf(drti, sizeof (drti), "/usr/lib%s/dtrace/drti.o",
+ use_32 ? "":"32");
+
+ 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);
+#endif
+
+ if ((status = system(cmd)) == -1) {
+ ret = dt_link_error(dtp, NULL, -1, NULL,
+ "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, NULL, -1, 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, -1, NULL,
+ "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);
+
+#if !defined(sun)
+ unlink(tfile);
+#endif
+ return (ret);
+}