Imported Upstream version 0.7.2upstream/0.7.2

1 files changed, 978 insertions, 0 deletions

diff --git a/ltrace-elf.c b/ltrace-elf.c
new file mode 100644
index 0000000..c571d2a
--- /dev/null
+++ b/ltrace-elf.c
@@ -0,0 +1,978 @@
+/*
+ * This file is part of ltrace.
+ * Copyright (C) 2006,2010,2011,2012 Petr Machata, Red Hat Inc.
+ * Copyright (C) 2010 Zachary T Welch, CodeSourcery
+ * Copyright (C) 2010 Joe Damato
+ * Copyright (C) 1997,1998,2001,2004,2007,2008,2009 Juan Cespedes
+ * Copyright (C) 2006 Olaf Hering, SUSE Linux GmbH
+ * Copyright (C) 2006 Eric Vaitl, Cisco Systems, Inc.
+ * Copyright (C) 2006 Paul Gilliam, IBM Corporation
+ * Copyright (C) 2006 Ian Wienand
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ */
+
+#include "config.h"
+
+#include <assert.h>
+#ifdef	__linux__
+#include <endian.h>
+#endif
+#include <errno.h>
+#include <fcntl.h>
+#include <gelf.h>
+#include <inttypes.h>
+#include <search.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "backend.h"
+#include "filter.h"
+#include "library.h"
+#include "ltrace-elf.h"
+#include "proc.h"
+#include "debug.h"
+#include "options.h"
+
+#ifndef ARCH_HAVE_LTELF_DATA
+int
+arch_elf_init(struct ltelf *lte, struct library *lib)
+{
+	return 0;
+}
+
+void
+arch_elf_destroy(struct ltelf *lte)
+{
+}
+#endif
+
+int
+default_elf_add_plt_entry(struct Process *proc, struct ltelf *lte,
+			  const char *a_name, GElf_Rela *rela, size_t ndx,
+			  struct library_symbol **ret)
+{
+	char *name = strdup(a_name);
+	if (name == NULL) {
+	fail_message:
+		fprintf(stderr, "Couldn't create symbol for PLT entry: %s\n",
+			strerror(errno));
+	fail:
+		free(name);
+		return -1;
+	}
+
+	GElf_Addr addr = arch_plt_sym_val(lte, ndx, rela);
+
+	struct library_symbol *libsym = malloc(sizeof(*libsym));
+	if (libsym == NULL)
+		goto fail_message;
+
+	/* XXX The double cast should be removed when
+	 * arch_addr_t becomes integral type.  */
+	arch_addr_t taddr = (arch_addr_t)
+		(uintptr_t)(addr + lte->bias);
+
+	if (library_symbol_init(libsym, taddr, name, 1, LS_TOPLT_EXEC) < 0) {
+		free(libsym);
+		goto fail;
+	}
+
+	libsym->next = *ret;
+	*ret = libsym;
+	return 0;
+}
+
+#ifndef ARCH_HAVE_ADD_PLT_ENTRY
+enum plt_status
+arch_elf_add_plt_entry(struct Process *proc, struct ltelf *lte,
+		       const char *a_name, GElf_Rela *rela, size_t ndx,
+		       struct library_symbol **ret)
+{
+	return plt_default;
+}
+#endif
+
+Elf_Data *
+elf_loaddata(Elf_Scn *scn, GElf_Shdr *shdr)
+{
+	Elf_Data *data = elf_getdata(scn, NULL);
+	if (data == NULL || elf_getdata(scn, data) != NULL
+	    || data->d_off || data->d_size != shdr->sh_size)
+		return NULL;
+	return data;
+}
+
+static int
+elf_get_section_if(struct ltelf *lte, Elf_Scn **tgt_sec, GElf_Shdr *tgt_shdr,
+		   int (*predicate)(Elf_Scn *, GElf_Shdr *, void *data),
+		   void *data)
+{
+	int i;
+	for (i = 1; i < lte->ehdr.e_shnum; ++i) {
+		Elf_Scn *scn;
+		GElf_Shdr shdr;
+
+		scn = elf_getscn(lte->elf, i);
+		if (scn == NULL || gelf_getshdr(scn, &shdr) == NULL) {
+			debug(1, "Couldn't read section or header.");
+			return -1;
+		}
+		if (predicate(scn, &shdr, data)) {
+			*tgt_sec = scn;
+			*tgt_shdr = shdr;
+			return 0;
+		}
+	}
+	return -1;
+
+}
+
+static int
+inside_p(Elf_Scn *scn, GElf_Shdr *shdr, void *data)
+{
+	GElf_Addr addr = *(GElf_Addr *)data;
+	return addr >= shdr->sh_addr
+		&& addr < shdr->sh_addr + shdr->sh_size;
+}
+
+int
+elf_get_section_covering(struct ltelf *lte, GElf_Addr addr,
+			 Elf_Scn **tgt_sec, GElf_Shdr *tgt_shdr)
+{
+	return elf_get_section_if(lte, tgt_sec, tgt_shdr,
+				  &inside_p, &addr);
+}
+
+static int
+type_p(Elf_Scn *scn, GElf_Shdr *shdr, void *data)
+{
+	GElf_Word type = *(GElf_Word *)data;
+	return shdr->sh_type == type;
+}
+
+int
+elf_get_section_type(struct ltelf *lte, GElf_Word type,
+		     Elf_Scn **tgt_sec, GElf_Shdr *tgt_shdr)
+{
+	return elf_get_section_if(lte, tgt_sec, tgt_shdr,
+				  &type_p, &type);
+}
+
+struct section_named_data {
+	struct ltelf *lte;
+	const char *name;
+};
+
+static int
+name_p(Elf_Scn *scn, GElf_Shdr *shdr, void *d)
+{
+	struct section_named_data *data = d;
+	const char *name = elf_strptr(data->lte->elf,
+				      data->lte->ehdr.e_shstrndx,
+				      shdr->sh_name);
+	return strcmp(name, data->name) == 0;
+}
+
+int
+elf_get_section_named(struct ltelf *lte, const char *name,
+		     Elf_Scn **tgt_sec, GElf_Shdr *tgt_shdr)
+{
+	struct section_named_data data = {
+		.lte = lte,
+		.name = name,
+	};
+	return elf_get_section_if(lte, tgt_sec, tgt_shdr,
+				  &name_p, &data);
+}
+
+static int
+need_data(Elf_Data *data, GElf_Xword offset, GElf_Xword size)
+{
+	assert(data != NULL);
+	if (data->d_size < size || offset > data->d_size - size) {
+		debug(1, "Not enough data to read %"PRId64"-byte value"
+		      " at offset %"PRId64".", size, offset);
+		return -1;
+	}
+	return 0;
+}
+
+#define DEF_READER(NAME, SIZE)						\
+	int								\
+	NAME(Elf_Data *data, GElf_Xword offset, uint##SIZE##_t *retp)	\
+	{								\
+		if (!need_data(data, offset, SIZE / 8) < 0)		\
+			return -1;					\
+									\
+		if (data->d_buf == NULL) /* NODATA section */ {		\
+			*retp = 0;					\
+			return 0;					\
+		}							\
+									\
+		union {							\
+			uint##SIZE##_t dst;				\
+			char buf[0];					\
+		} u;							\
+		memcpy(u.buf, data->d_buf + offset, sizeof(u.dst));	\
+		*retp = u.dst;						\
+		return 0;						\
+	}
+
+DEF_READER(elf_read_u16, 16)
+DEF_READER(elf_read_u32, 32)
+DEF_READER(elf_read_u64, 64)
+
+#undef DEF_READER
+
+int
+open_elf(struct ltelf *lte, const char *filename)
+{
+	lte->fd = open(filename, O_RDONLY);
+	if (lte->fd == -1)
+		return 1;
+
+	elf_version(EV_CURRENT);
+
+#ifdef HAVE_ELF_C_READ_MMAP
+	lte->elf = elf_begin(lte->fd, ELF_C_READ_MMAP, NULL);
+#else
+	lte->elf = elf_begin(lte->fd, ELF_C_READ, NULL);
+#endif
+
+	if (lte->elf == NULL || elf_kind(lte->elf) != ELF_K_ELF) {
+		fprintf(stderr, "\"%s\" is not an ELF file\n", filename);
+		exit(EXIT_FAILURE);
+	}
+
+	if (gelf_getehdr(lte->elf, &lte->ehdr) == NULL) {
+		fprintf(stderr, "can't read ELF header of \"%s\": %s\n",
+			filename, elf_errmsg(-1));
+		exit(EXIT_FAILURE);
+	}
+
+	if (lte->ehdr.e_type != ET_EXEC && lte->ehdr.e_type != ET_DYN) {
+		fprintf(stderr, "\"%s\" is neither an ELF executable"
+			" nor a shared library\n", filename);
+		exit(EXIT_FAILURE);
+	}
+
+	if (1
+#ifdef LT_ELF_MACHINE
+	    && (lte->ehdr.e_ident[EI_CLASS] != LT_ELFCLASS
+		|| lte->ehdr.e_machine != LT_ELF_MACHINE)
+#endif
+#ifdef LT_ELF_MACHINE2
+	    && (lte->ehdr.e_ident[EI_CLASS] != LT_ELFCLASS2
+		|| lte->ehdr.e_machine != LT_ELF_MACHINE2)
+#endif
+#ifdef LT_ELF_MACHINE3
+	    && (lte->ehdr.e_ident[EI_CLASS] != LT_ELFCLASS3
+		|| lte->ehdr.e_machine != LT_ELF_MACHINE3)
+#endif
+		) {
+		fprintf(stderr,
+			"\"%s\" is ELF from incompatible architecture\n",
+			filename);
+		exit(EXIT_FAILURE);
+	}
+
+	return 0;
+}
+
+static void
+read_symbol_table(struct ltelf *lte, const char *filename,
+		  Elf_Scn *scn, GElf_Shdr *shdr, const char *name,
+		  Elf_Data **datap, size_t *countp, const char **strsp)
+{
+	*datap = elf_getdata(scn, NULL);
+	*countp = shdr->sh_size / shdr->sh_entsize;
+	if ((*datap == NULL || elf_getdata(scn, *datap) != NULL)
+	    && options.static_filter != NULL) {
+		fprintf(stderr, "Couldn't get data of section"
+			" %s from \"%s\": %s\n",
+			name, filename, elf_errmsg(-1));
+		exit(EXIT_FAILURE);
+	}
+
+	scn = elf_getscn(lte->elf, shdr->sh_link);
+	GElf_Shdr shdr2;
+	if (scn == NULL || gelf_getshdr(scn, &shdr2) == NULL) {
+		fprintf(stderr, "Couldn't get header of section"
+			" #%d from \"%s\": %s\n",
+			shdr2.sh_link, filename, elf_errmsg(-1));
+		exit(EXIT_FAILURE);
+	}
+
+	Elf_Data *data = elf_getdata(scn, NULL);
+	if (data == NULL || elf_getdata(scn, data) != NULL
+	    || shdr2.sh_size != data->d_size || data->d_off) {
+		fprintf(stderr, "Couldn't get data of section"
+			" #%d from \"%s\": %s\n",
+			shdr2.sh_link, filename, elf_errmsg(-1));
+		exit(EXIT_FAILURE);
+	}
+
+	*strsp = data->d_buf;
+}
+
+static int
+do_init_elf(struct ltelf *lte, const char *filename)
+{
+	int i;
+	GElf_Addr relplt_addr = 0;
+	GElf_Addr soname_offset = 0;
+
+	debug(DEBUG_FUNCTION, "do_init_elf(filename=%s)", filename);
+	debug(1, "Reading ELF from %s...", filename);
+
+	for (i = 1; i < lte->ehdr.e_shnum; ++i) {
+		Elf_Scn *scn;
+		GElf_Shdr shdr;
+		const char *name;
+
+		scn = elf_getscn(lte->elf, i);
+		if (scn == NULL || gelf_getshdr(scn, &shdr) == NULL) {
+			fprintf(stderr,	"Couldn't get section #%d from"
+				" \"%s\": %s\n", i, filename, elf_errmsg(-1));
+			exit(EXIT_FAILURE);
+		}
+
+		name = elf_strptr(lte->elf, lte->ehdr.e_shstrndx, shdr.sh_name);
+		if (name == NULL) {
+			fprintf(stderr,	"Couldn't get name of section #%d from"
+				" \"%s\": %s\n", i, filename, elf_errmsg(-1));
+			exit(EXIT_FAILURE);
+		}
+
+		if (shdr.sh_type == SHT_SYMTAB) {
+			read_symbol_table(lte, filename,
+					  scn, &shdr, name, &lte->symtab,
+					  &lte->symtab_count, &lte->strtab);
+
+		} else if (shdr.sh_type == SHT_DYNSYM) {
+			read_symbol_table(lte, filename,
+					  scn, &shdr, name, &lte->dynsym,
+					  &lte->dynsym_count, &lte->dynstr);
+
+		} else if (shdr.sh_type == SHT_DYNAMIC) {
+			Elf_Data *data;
+			size_t j;
+
+			lte->dyn_addr = shdr.sh_addr + lte->bias;
+			lte->dyn_sz = shdr.sh_size;
+
+			data = elf_getdata(scn, NULL);
+			if (data == NULL || elf_getdata(scn, data) != NULL) {
+				fprintf(stderr, "Couldn't get .dynamic data"
+					" from \"%s\": %s\n",
+					filename, strerror(errno));
+				exit(EXIT_FAILURE);
+			}
+
+			for (j = 0; j < shdr.sh_size / shdr.sh_entsize; ++j) {
+				GElf_Dyn dyn;
+
+				if (gelf_getdyn(data, j, &dyn) == NULL) {
+					fprintf(stderr, "Couldn't get .dynamic"
+						" data from \"%s\": %s\n",
+						filename, strerror(errno));
+					exit(EXIT_FAILURE);
+				}
+				if (dyn.d_tag == DT_JMPREL)
+					relplt_addr = dyn.d_un.d_ptr;
+				else if (dyn.d_tag == DT_PLTRELSZ)
+					lte->relplt_size = dyn.d_un.d_val;
+				else if (dyn.d_tag == DT_SONAME)
+					soname_offset = dyn.d_un.d_val;
+			}
+		} else if (shdr.sh_type == SHT_PROGBITS
+			   || shdr.sh_type == SHT_NOBITS) {
+			if (strcmp(name, ".plt") == 0) {
+				lte->plt_addr = shdr.sh_addr;
+				lte->plt_size = shdr.sh_size;
+				lte->plt_data = elf_loaddata(scn, &shdr);
+				if (lte->plt_data == NULL)
+					fprintf(stderr,
+						"Can't load .plt data\n");
+				lte->plt_flags = shdr.sh_flags;
+			}
+#ifdef ARCH_SUPPORTS_OPD
+			else if (strcmp(name, ".opd") == 0) {
+				lte->opd_addr = (GElf_Addr *) (long) shdr.sh_addr;
+				lte->opd_size = shdr.sh_size;
+				lte->opd = elf_rawdata(scn, NULL);
+			}
+#endif
+		}
+	}
+
+	if (lte->dynsym == NULL || lte->dynstr == NULL) {
+		fprintf(stderr, "Couldn't find .dynsym or .dynstr in \"%s\"\n",
+			filename);
+		exit(EXIT_FAILURE);
+	}
+
+	if (!relplt_addr || !lte->plt_addr) {
+		debug(1, "%s has no PLT relocations", filename);
+		lte->relplt = NULL;
+		lte->relplt_count = 0;
+	} else if (lte->relplt_size == 0) {
+		debug(1, "%s has unknown PLT size", filename);
+		lte->relplt = NULL;
+		lte->relplt_count = 0;
+	} else {
+
+		for (i = 1; i < lte->ehdr.e_shnum; ++i) {
+			Elf_Scn *scn;
+			GElf_Shdr shdr;
+
+			scn = elf_getscn(lte->elf, i);
+			if (scn == NULL || gelf_getshdr(scn, &shdr) == NULL) {
+				fprintf(stderr, "Couldn't get section header"
+					" from \"%s\": %s\n",
+					filename, elf_errmsg(-1));
+				exit(EXIT_FAILURE);
+			}
+			if (shdr.sh_addr == relplt_addr
+			    && shdr.sh_size == lte->relplt_size) {
+				lte->relplt = elf_getdata(scn, NULL);
+				lte->relplt_count =
+				    shdr.sh_size / shdr.sh_entsize;
+				if (lte->relplt == NULL
+				    || elf_getdata(scn, lte->relplt) != NULL) {
+					fprintf(stderr, "Couldn't get .rel*.plt"
+						" data from \"%s\": %s\n",
+						filename, elf_errmsg(-1));
+					exit(EXIT_FAILURE);
+				}
+				break;
+			}
+		}
+
+		if (i == lte->ehdr.e_shnum) {
+			fprintf(stderr,
+				"Couldn't find .rel*.plt section in \"%s\"\n",
+				filename);
+			exit(EXIT_FAILURE);
+		}
+
+		debug(1, "%s %zd PLT relocations", filename, lte->relplt_count);
+	}
+
+	if (soname_offset != 0)
+		lte->soname = lte->dynstr + soname_offset;
+
+	return 0;
+}
+
+void
+do_close_elf(struct ltelf *lte)
+{
+	debug(DEBUG_FUNCTION, "do_close_elf()");
+	arch_elf_destroy(lte);
+	elf_end(lte->elf);
+	close(lte->fd);
+}
+
+int
+elf_get_sym_info(struct ltelf *lte, const char *filename,
+		 size_t sym_index, GElf_Rela *rela, GElf_Sym *sym)
+{
+	int i = sym_index;
+	GElf_Rel rel;
+	void *ret;
+
+	if (lte->relplt->d_type == ELF_T_REL) {
+		ret = gelf_getrel(lte->relplt, i, &rel);
+		rela->r_offset = rel.r_offset;
+		rela->r_info = rel.r_info;
+		rela->r_addend = 0;
+	} else {
+		ret = gelf_getrela(lte->relplt, i, rela);
+	}
+
+	if (ret == NULL
+	    || ELF64_R_SYM(rela->r_info) >= lte->dynsym_count
+	    || gelf_getsym(lte->dynsym, ELF64_R_SYM(rela->r_info),
+			   sym) == NULL) {
+		fprintf(stderr,
+			"Couldn't get relocation from \"%s\": %s\n",
+			filename, elf_errmsg(-1));
+		exit(EXIT_FAILURE);
+	}
+
+	return 0;
+}
+
+#ifndef ARCH_HAVE_GET_SYMINFO
+int
+arch_get_sym_info(struct ltelf *lte, const char *filename,
+		  size_t sym_index, GElf_Rela *rela, GElf_Sym *sym)
+{
+	return elf_get_sym_info(lte, filename, sym_index, rela, sym);
+}
+#endif
+
+static void
+mark_chain_latent(struct library_symbol *libsym)
+{
+	for (; libsym != NULL; libsym = libsym->next) {
+		debug(DEBUG_FUNCTION, "marking %s latent", libsym->name);
+		libsym->latent = 1;
+	}
+}
+
+static int
+populate_plt(struct Process *proc, const char *filename,
+	     struct ltelf *lte, struct library *lib,
+	     int latent_plts)
+{
+	size_t i;
+	for (i = 0; i < lte->relplt_count; ++i) {
+		GElf_Rela rela;
+		GElf_Sym sym;
+
+		if (arch_get_sym_info(lte, filename, i, &rela, &sym) < 0)
+			continue; /* Skip this entry.  */
+
+		char const *name = lte->dynstr + sym.st_name;
+
+		/* If the symbol wasn't matched, reject it, unless we
+		 * need to keep latent PLT breakpoints for tracing
+		 * exports.  */
+		int matched = filter_matches_symbol(options.plt_filter,
+						    name, lib);
+		if (!matched && !latent_plts)
+			continue;
+
+		struct library_symbol *libsym = NULL;
+		switch (arch_elf_add_plt_entry(proc, lte, name,
+					       &rela, i, &libsym)) {
+		case plt_default:
+			if (default_elf_add_plt_entry(proc, lte, name,
+						      &rela, i, &libsym) < 0)
+			/* fall-through */
+		case plt_fail:
+				return -1;
+			/* fall-through */
+		case plt_ok:
+			if (libsym != NULL) {
+				/* If we are adding those symbols just
+				 * for tracing exports, mark them all
+				 * latent.  */
+				if (!matched)
+					mark_chain_latent(libsym);
+				library_add_symbol(lib, libsym);
+			}
+		}
+	}
+	return 0;
+}
+
+/* When -x rules result in request to trace several aliases, we only
+ * want to add such symbol once.  The only way that those symbols
+ * differ in is their name, e.g. in glibc you have __GI___libc_free,
+ * __cfree, __free, __libc_free, cfree and free all defined on the
+ * same address.  So instead we keep this unique symbol struct for
+ * each address, and replace name in libsym with a shorter variant if
+ * we find it.  */
+struct unique_symbol {
+	arch_addr_t addr;
+	struct library_symbol *libsym;
+};
+
+static int
+unique_symbol_cmp(const void *key, const void *val)
+{
+	const struct unique_symbol *sym_key = key;
+	const struct unique_symbol *sym_val = val;
+	return sym_key->addr != sym_val->addr;
+}
+
+static enum callback_status
+symbol_with_address(struct library_symbol *sym, void *addrptr)
+{
+	return sym->enter_addr == *(arch_addr_t *)addrptr
+		? CBS_STOP : CBS_CONT;
+}
+
+static int
+populate_this_symtab(struct Process *proc, const char *filename,
+		     struct ltelf *lte, struct library *lib,
+		     Elf_Data *symtab, const char *strtab, size_t size,
+		     struct library_exported_name **names)
+{
+	/* If a valid NAMES is passed, we pass in *NAMES a list of
+	 * symbol names that this library exports.  */
+	if (names != NULL)
+		*names = NULL;
+
+	/* Using sorted array would be arguably better, but this
+	 * should be well enough for the number of symbols that we
+	 * typically deal with.  */
+	size_t num_symbols = 0;
+	struct unique_symbol *symbols = malloc(sizeof(*symbols) * size);
+	if (symbols == NULL) {
+		fprintf(stderr, "couldn't insert symbols for -x: %s\n",
+			strerror(errno));
+		return -1;
+	}
+
+	GElf_Word secflags[lte->ehdr.e_shnum];
+	size_t i;
+	for (i = 1; i < lte->ehdr.e_shnum; ++i) {
+		Elf_Scn *scn = elf_getscn(lte->elf, i);
+		if (scn == NULL)
+			continue;
+		GElf_Shdr shdr;
+		if (gelf_getshdr(scn, &shdr) == NULL)
+			continue;
+		secflags[i] = shdr.sh_flags;
+	}
+
+	for (i = 0; i < size; ++i) {
+		GElf_Sym sym;
+		if (gelf_getsym(symtab, i, &sym) == NULL) {
+		fail:
+			fprintf(stderr,
+				"couldn't get symbol #%zd from %s: %s\n",
+				i, filename, elf_errmsg(-1));
+			continue;
+		}
+
+		/* XXX support IFUNC as well.  */
+		if (GELF_ST_TYPE(sym.st_info) != STT_FUNC
+		    || sym.st_value == 0
+		    || sym.st_shndx == STN_UNDEF)
+			continue;
+
+		/* Find symbol name and snip version.  */
+		const char *orig_name = strtab + sym.st_name;
+		const char *version = strchr(orig_name, '@');
+		size_t len = version != NULL ? (assert(version > orig_name),
+						(size_t)(version - orig_name))
+			: strlen(orig_name);
+		char name[len + 1];
+		memcpy(name, orig_name, len);
+		name[len] = 0;
+
+		/* If we are interested in exports, store this name.  */
+		char *name_copy = NULL;
+		if (names != NULL) {
+			struct library_exported_name *export = NULL;
+			name_copy = strdup(name);
+
+			if (name_copy == NULL
+			    || (export = malloc(sizeof(*export))) == NULL) {
+				free(name_copy);
+				fprintf(stderr, "Couldn't store symbol %s.  "
+					"Tracing may be incomplete.\n", name);
+			} else {
+				export->name = name_copy;
+				export->own_name = 1;
+				export->next = *names;
+				*names = export;
+			}
+		}
+
+		/* If the symbol is not matched, skip it.  We already
+		 * stored it to export list above.  */
+		if (!filter_matches_symbol(options.static_filter, name, lib))
+			continue;
+
+		arch_addr_t addr = (arch_addr_t)
+			(uintptr_t)(sym.st_value + lte->bias);
+		arch_addr_t naddr;
+
+		/* On arches that support OPD, the value of typical
+		 * function symbol will be a pointer to .opd, but some
+		 * will point directly to .text.  We don't want to
+		 * translate those.  */
+		if (secflags[sym.st_shndx] & SHF_EXECINSTR) {
+			naddr = addr;
+		} else if (arch_translate_address(lte, addr, &naddr) < 0) {
+			fprintf(stderr,
+				"couldn't translate address of %s@%s: %s\n",
+				name, lib->soname, strerror(errno));
+			continue;
+		}
+
+		char *full_name;
+		int own_full_name = 1;
+		if (name_copy == NULL) {
+			full_name = strdup(name);
+			if (full_name == NULL)
+				goto fail;
+		} else {
+			full_name = name_copy;
+			own_full_name = 0;
+		}
+
+		/* Look whether we already have a symbol for this
+		 * address.  If not, add this one.  */
+		struct unique_symbol key = { naddr, NULL };
+		struct unique_symbol *unique
+			= lsearch(&key, symbols, &num_symbols,
+				  sizeof(*symbols), &unique_symbol_cmp);
+
+		if (unique->libsym == NULL) {
+			struct library_symbol *libsym = malloc(sizeof(*libsym));
+			if (libsym == NULL
+			    || library_symbol_init(libsym, naddr,
+						   full_name, own_full_name,
+						   LS_TOPLT_NONE) < 0) {
+				--num_symbols;
+				goto fail;
+			}
+			unique->libsym = libsym;
+			unique->addr = naddr;
+
+		} else if (strlen(full_name) < strlen(unique->libsym->name)) {
+			library_symbol_set_name(unique->libsym,
+						full_name, own_full_name);
+
+		} else if (own_full_name) {
+			free(full_name);
+		}
+	}
+
+	/* Now we do the union of this set of unique symbols with
+	 * what's already in the library.  */
+	for (i = 0; i < num_symbols; ++i) {
+		struct library_symbol *this_sym = symbols[i].libsym;
+		assert(this_sym != NULL);
+		struct library_symbol *other
+			= library_each_symbol(lib, NULL, symbol_with_address,
+					      &this_sym->enter_addr);
+		if (other != NULL) {
+			library_symbol_destroy(this_sym);
+			free(this_sym);
+			symbols[i].libsym = NULL;
+		}
+	}
+
+	for (i = 0; i < num_symbols; ++i)
+		if (symbols[i].libsym != NULL)
+			library_add_symbol(lib, symbols[i].libsym);
+
+	free(symbols);
+	return 0;
+}
+
+static int
+populate_symtab(struct Process *proc, const char *filename,
+		struct ltelf *lte, struct library *lib,
+		int symtabs, int exports)
+{
+	int status;
+	if (symtabs && lte->symtab != NULL && lte->strtab != NULL
+	    && (status = populate_this_symtab(proc, filename, lte, lib,
+					      lte->symtab, lte->strtab,
+					      lte->symtab_count, NULL)) < 0)
+		return status;
+
+	/* Check whether we want to trace symbols implemented by this
+	 * library (-l).  */
+	struct library_exported_name **names = NULL;
+	if (exports) {
+		debug(DEBUG_FUNCTION, "-l matches %s", lib->soname);
+		names = &lib->exported_names;
+	}
+
+	return populate_this_symtab(proc, filename, lte, lib,
+				    lte->dynsym, lte->dynstr,
+				    lte->dynsym_count, names);
+}
+
+static int
+read_module(struct library *lib, struct Process *proc,
+	    const char *filename, GElf_Addr bias, int main)
+{
+	struct ltelf lte = {};
+	if (open_elf(&lte, filename) < 0)
+		return -1;
+
+	/* XXX When we abstract ABI into a module, this should instead
+	 * become something like
+	 *
+	 *    proc->abi = arch_get_abi(lte.ehdr);
+	 *
+	 * The code in open_elf needs to be replaced by this logic.
+	 * Be warned that libltrace.c calls open_elf as well to
+	 * determine whether ABI is supported.  This is to get
+	 * reasonable error messages when trying to run 64-bit binary
+	 * with 32-bit ltrace.  It is desirable to preserve this.  */
+	proc->e_machine = lte.ehdr.e_machine;
+	proc->e_class = lte.ehdr.e_ident[EI_CLASS];
+	get_arch_dep(proc);
+
+	/* Find out the base address.  For PIE main binaries we look
+	 * into auxv, otherwise we scan phdrs.  */
+	if (main && lte.ehdr.e_type == ET_DYN) {
+		arch_addr_t entry;
+		if (process_get_entry(proc, &entry, NULL) < 0) {
+			fprintf(stderr, "Couldn't find entry of PIE %s\n",
+				filename);
+			return -1;
+		}
+		/* XXX The double cast should be removed when
+		 * arch_addr_t becomes integral type.  */
+		lte.entry_addr = (GElf_Addr)(uintptr_t)entry;
+		lte.bias = (GElf_Addr)(uintptr_t)entry - lte.ehdr.e_entry;
+
+	} else {
+		GElf_Phdr phdr;
+		size_t i;
+		for (i = 0; gelf_getphdr (lte.elf, i, &phdr) != NULL; ++i) {
+			if (phdr.p_type == PT_LOAD) {
+				lte.base_addr = phdr.p_vaddr + bias;
+				break;
+			}
+		}
+
+		lte.bias = bias;
+		lte.entry_addr = lte.ehdr.e_entry + lte.bias;
+
+		if (lte.base_addr == 0) {
+			fprintf(stderr,
+				"Couldn't determine base address of %s\n",
+				filename);
+			return -1;
+		}
+	}
+
+	if (do_init_elf(&lte, filename) < 0)
+		return -1;
+
+	if (arch_elf_init(&lte, lib) < 0) {
+		fprintf(stderr, "Backend initialization failed.\n");
+		return -1;
+	}
+
+	int status = 0;
+	if (lib == NULL)
+		goto fail;
+
+	/* Note that we set soname and pathname as soon as they are
+	 * allocated, so in case of further errors, this get released
+	 * when LIB is release, which should happen in the caller when
+	 * we return error.  */
+
+	if (lib->pathname == NULL) {
+		char *pathname = strdup(filename);
+		if (pathname == NULL)
+			goto fail;
+		library_set_pathname(lib, pathname, 1);
+	}
+
+	if (lte.soname != NULL) {
+		char *soname = strdup(lte.soname);
+		if (soname == NULL)
+			goto fail;
+		library_set_soname(lib, soname, 1);
+	} else {
+		const char *soname = rindex(lib->pathname, '/') + 1;
+		if (soname == NULL)
+			soname = lib->pathname;
+		library_set_soname(lib, soname, 0);
+	}
+
+	/* XXX The double cast should be removed when
+	 * arch_addr_t becomes integral type.  */
+	arch_addr_t entry = (arch_addr_t)(uintptr_t)lte.entry_addr;
+	if (arch_translate_address(&lte, entry, &entry) < 0)
+		goto fail;
+
+	/* XXX The double cast should be removed when
+	 * arch_addr_t becomes integral type.  */
+	lib->base = (arch_addr_t)(uintptr_t)lte.base_addr;
+	lib->entry = entry;
+	/* XXX The double cast should be removed when
+	 * arch_addr_t becomes integral type.  */
+	lib->dyn_addr = (arch_addr_t)(uintptr_t)lte.dyn_addr;
+
+	/* There are two reasons that we need to inspect symbol tables
+	 * or populate PLT entries.  Either the user requested
+	 * corresponding tracing features (respectively -x and -e), or
+	 * they requested tracing exported symbols (-l).
+	 *
+	 * In the latter case we need to keep even those PLT slots
+	 * that are not requested by -e (but we keep them latent).  We
+	 * also need to inspect .dynsym to find what exports this
+	 * library provide, to turn on existing latent PLT
+	 * entries.  */
+
+	int plts = filter_matches_library(options.plt_filter, lib);
+	if ((plts || options.export_filter != NULL)
+	    && populate_plt(proc, filename, &lte, lib,
+			    options.export_filter != NULL) < 0)
+		goto fail;
+
+	int exports = filter_matches_library(options.export_filter, lib);
+	int symtabs = filter_matches_library(options.static_filter, lib);
+	if ((symtabs || exports)
+	    && populate_symtab(proc, filename, &lte, lib,
+			       symtabs, exports) < 0)
+		goto fail;
+
+done:
+	do_close_elf(&lte);
+	return status;
+
+fail:
+	status = -1;
+	goto done;
+}
+
+int
+ltelf_read_library(struct library *lib, struct Process *proc,
+		   const char *filename, GElf_Addr bias)
+{
+	return read_module(lib, proc, filename, bias, 0);
+}
+
+
+struct library *
+ltelf_read_main_binary(struct Process *proc, const char *path)
+{
+	struct library *lib = malloc(sizeof(*lib));
+	if (lib == NULL)
+		return NULL;
+	library_init(lib, LT_LIBTYPE_MAIN);
+	library_set_pathname(lib, path, 0);
+
+	/* There is a race between running the process and reading its
+	 * binary for internal consumption.  So open the binary from
+	 * the /proc filesystem.  XXX Note that there is similar race
+	 * for libraries, but there we don't have a nice answer like
+	 * that.  Presumably we could read the DSOs from the process
+	 * memory image, but that's not currently done.  */
+	char *fname = pid2name(proc->pid);
+	if (fname == NULL)
+		return NULL;
+	if (read_module(lib, proc, fname, 0, 1) < 0) {
+		library_destroy(lib);
+		free(lib);
+		return NULL;
+	}
+	free(fname);
+
+	return lib;
+}