1 files changed, 356 insertions, 166 deletions

diff --git a/breakpoints.c b/breakpoints.c
index ba3b060..258be93 100644
--- a/breakpoints.c
+++ b/breakpoints.c
@@ -1,230 +1,420 @@
+/*
+ * This file is part of ltrace.
+ * Copyright (C) 2006,2007,2011,2012 Petr Machata, Red Hat Inc.
+ * Copyright (C) 2009 Juan Cespedes
+ * Copyright (C) 1998,2001,2002,2003,2007,2008,2009 Juan Cespedes
+ * 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>
+#include <errno.h>
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <assert.h>
 
 #ifdef __powerpc__
 #include <sys/ptrace.h>
 #endif
 
-#include "common.h"
+#include "backend.h"
+#include "breakpoint.h"
+#include "debug.h"
+#include "library.h"
+#include "ltrace-elf.h"
+#include "proc.h"
+
+#ifndef ARCH_HAVE_TRANSLATE_ADDRESS
+int
+arch_translate_address_dyn(struct Process *proc,
+		       arch_addr_t addr, arch_addr_t *ret)
+{
+	*ret = addr;
+	return 0;
+}
+
+struct ltelf;
+int
+arch_translate_address(struct ltelf *lte,
+		       arch_addr_t addr, arch_addr_t *ret)
+{
+	*ret = addr;
+	return 0;
+}
+#endif
+
+void
+breakpoint_on_hit(struct breakpoint *bp, struct Process *proc)
+{
+	assert(bp != NULL);
+	if (bp->cbs != NULL && bp->cbs->on_hit != NULL)
+		(bp->cbs->on_hit)(bp, proc);
+}
+
+void
+breakpoint_on_continue(struct breakpoint *bp, struct Process *proc)
+{
+	assert(bp != NULL);
+	if (bp->cbs != NULL && bp->cbs->on_continue != NULL)
+		(bp->cbs->on_continue)(bp, proc);
+	else
+		continue_after_breakpoint(proc, bp);
+}
+
+void
+breakpoint_on_retract(struct breakpoint *bp, struct Process *proc)
+{
+	assert(bp != NULL);
+	if (bp->cbs != NULL && bp->cbs->on_retract != NULL)
+		(bp->cbs->on_retract)(bp, proc);
+}
 
 /*****************************************************************************/
 
-Breakpoint *
-address2bpstruct(Process *proc, void *addr) {
+struct breakpoint *
+address2bpstruct(Process *proc, void *addr)
+{
+	assert(proc != NULL);
+	assert(proc->breakpoints != NULL);
+	assert(proc->leader == proc);
 	debug(DEBUG_FUNCTION, "address2bpstruct(pid=%d, addr=%p)", proc->pid, addr);
 	return dict_find_entry(proc->breakpoints, addr);
 }
 
+#ifndef ARCH_HAVE_BREAKPOINT_DATA
+int
+arch_breakpoint_init(struct Process *proc, struct breakpoint *sbp)
+{
+	return 0;
+}
+
 void
-insert_breakpoint(Process *proc, void *addr,
-		  struct library_symbol *libsym) {
-	Breakpoint *sbp;
+arch_breakpoint_destroy(struct breakpoint *sbp)
+{
+}
 
-	debug(DEBUG_FUNCTION, "insert_breakpoint(pid=%d, addr=%p, symbol=%s)", proc->pid, addr, libsym ? libsym->name : "NULL");
-	debug(1, "symbol=%s, addr=%p", libsym?libsym->name:"(nil)", addr);
+int
+arch_breakpoint_clone(struct breakpoint *retp, struct breakpoint *sbp)
+{
+	return 0;
+}
+#endif
 
-	if (!addr)
+static void
+breakpoint_init_base(struct breakpoint *bp, struct Process *proc,
+		     arch_addr_t addr, struct library_symbol *libsym)
+{
+	bp->cbs = NULL;
+	bp->addr = addr;
+	memset(bp->orig_value, 0, sizeof(bp->orig_value));
+	bp->enabled = 0;
+	bp->libsym = libsym;
+}
+
+/* On second thought, I don't think we need PROC.  All the translation
+ * (arch_translate_address in particular) should be doable using
+ * static lookups of various sections in the ELF file.  We shouldn't
+ * need process for anything.  */
+int
+breakpoint_init(struct breakpoint *bp, struct Process *proc,
+		arch_addr_t addr, struct library_symbol *libsym)
+{
+	breakpoint_init_base(bp, proc, addr, libsym);
+	return arch_breakpoint_init(proc, bp);
+}
+
+void
+breakpoint_set_callbacks(struct breakpoint *bp, struct bp_callbacks *cbs)
+{
+	if (bp->cbs != NULL)
+		assert(bp->cbs == NULL);
+	bp->cbs = cbs;
+}
+
+void
+breakpoint_destroy(struct breakpoint *bp)
+{
+	if (bp == NULL)
 		return;
+	arch_breakpoint_destroy(bp);
+}
+
+int
+breakpoint_clone(struct breakpoint *retp, struct Process *new_proc,
+		 struct breakpoint *bp, struct Process *old_proc)
+{
+	struct library_symbol *libsym = NULL;
+	if (bp->libsym != NULL) {
+		int rc = proc_find_symbol(new_proc, bp->libsym, NULL, &libsym);
+		assert(rc == 0);
+	}
 
-	if (libsym)
-		libsym->needs_init = 0;
+	breakpoint_init_base(retp, new_proc, bp->addr, libsym);
+	memcpy(retp->orig_value, bp->orig_value, sizeof(bp->orig_value));
+	retp->enabled = bp->enabled;
+	if (arch_breakpoint_clone(retp, bp) < 0)
+		return -1;
+	breakpoint_set_callbacks(retp, bp->cbs);
+	return 0;
+}
+
+int
+breakpoint_turn_on(struct breakpoint *bp, struct Process *proc)
+{
+	bp->enabled++;
+	if (bp->enabled == 1) {
+		assert(proc->pid != 0);
+		enable_breakpoint(proc, bp);
+	}
+	return 0;
+}
+
+int
+breakpoint_turn_off(struct breakpoint *bp, struct Process *proc)
+{
+	bp->enabled--;
+	if (bp->enabled == 0)
+		disable_breakpoint(proc, bp);
+	assert(bp->enabled >= 0);
+	return 0;
+}
 
-	sbp = dict_find_entry(proc->breakpoints, addr);
-	if (!sbp) {
-		sbp = calloc(1, sizeof(Breakpoint));
-		if (!sbp) {
-			return;	/* TODO FIXME XXX: error_mem */
+struct breakpoint *
+insert_breakpoint(struct Process *proc, void *addr,
+		  struct library_symbol *libsym)
+{
+	Process *leader = proc->leader;
+
+	/* Only the group leader should be getting the breakpoints and
+	 * thus have ->breakpoint initialized.  */
+	assert(leader != NULL);
+	assert(leader->breakpoints != NULL);
+
+	debug(DEBUG_FUNCTION, "insert_breakpoint(pid=%d, addr=%p, symbol=%s)",
+	      proc->pid, addr, libsym ? libsym->name : "NULL");
+
+	assert(addr != 0);
+
+	/* XXX what we need to do instead is have a list of
+	 * breakpoints that are enabled at this address.  The
+	 * following works if every breakpoint is the same and there's
+	 * no extra data, but that doesn't hold anymore.  For now it
+	 * will suffice, about the only realistic case where we need
+	 * to have more than one breakpoint per address is return from
+	 * a recursive library call.  */
+	struct breakpoint *sbp = dict_find_entry(leader->breakpoints, addr);
+	if (sbp == NULL) {
+		sbp = malloc(sizeof(*sbp));
+		if (sbp == NULL
+		    || breakpoint_init(sbp, proc, addr, libsym) < 0) {
+			free(sbp);
+			return NULL;
+		}
+		if (proc_add_breakpoint(leader, sbp) < 0) {
+		fail:
+			breakpoint_destroy(sbp);
+			free(sbp);
+			return NULL;
 		}
-		dict_enter(proc->breakpoints, addr, sbp);
-		sbp->addr = addr;
-		sbp->libsym = libsym;
 	}
-#ifdef __arm__
-	sbp->thumb_mode = proc->thumb_mode;
-	proc->thumb_mode = 0;
-#endif
-	sbp->enabled++;
-	if (sbp->enabled == 1 && proc->pid)
-		enable_breakpoint(proc->pid, sbp);
+
+	if (breakpoint_turn_on(sbp, proc) < 0) {
+		proc_remove_breakpoint(leader, sbp);
+		goto fail;
+	}
+
+	return sbp;
 }
 
 void
-delete_breakpoint(Process *proc, void *addr) {
-	Breakpoint *sbp;
-
+delete_breakpoint(Process *proc, void *addr)
+{
 	debug(DEBUG_FUNCTION, "delete_breakpoint(pid=%d, addr=%p)", proc->pid, addr);
 
-	sbp = dict_find_entry(proc->breakpoints, addr);
-	assert(sbp);		/* FIXME: remove after debugging has been done. */
+	Process * leader = proc->leader;
+	assert(leader != NULL);
+
+	struct breakpoint *sbp = dict_find_entry(leader->breakpoints, addr);
+	assert(sbp != NULL);
 	/* This should only happen on out-of-memory conditions. */
 	if (sbp == NULL)
 		return;
 
-	sbp->enabled--;
-	if (sbp->enabled == 0)
-		disable_breakpoint(proc->pid, sbp);
-	assert(sbp->enabled >= 0);
+	if (breakpoint_turn_off(sbp, proc) < 0) {
+		fprintf(stderr, "Couldn't turn off the breakpoint %s@%p\n",
+			breakpoint_name(sbp), sbp->addr);
+		return;
+	}
+	if (sbp->enabled == 0) {
+		proc_remove_breakpoint(leader, sbp);
+		breakpoint_destroy(sbp);
+		free(sbp);
+	}
+}
+
+const char *
+breakpoint_name(const struct breakpoint *bp)
+{
+	assert(bp != NULL);
+	return bp->libsym != NULL ? bp->libsym->name : NULL;
+}
+
+struct library *
+breakpoint_library(const struct breakpoint *bp)
+{
+	assert(bp != NULL);
+	return bp->libsym != NULL ? bp->libsym->lib : NULL;
 }
 
 static void
-enable_bp_cb(void *addr, void *sbp, void *proc) {
+enable_bp_cb(void *addr, void *sbp, void *proc)
+{
 	debug(DEBUG_FUNCTION, "enable_bp_cb(pid=%d)", ((Process *)proc)->pid);
-	if (((Breakpoint *)sbp)->enabled) {
-		enable_breakpoint(((Process *)proc)->pid, sbp);
-	}
+	if (((struct breakpoint *)sbp)->enabled)
+		enable_breakpoint(proc, sbp);
 }
 
 void
-enable_all_breakpoints(Process *proc) {
+enable_all_breakpoints(Process *proc)
+{
 	debug(DEBUG_FUNCTION, "enable_all_breakpoints(pid=%d)", proc->pid);
-	if (proc->breakpoints_enabled <= 0) {
-#ifdef __powerpc__
-		unsigned long a;
-
-		/*
-		 * PPC HACK! (XXX FIXME TODO)
-		 * If the dynamic linker hasn't populated the PLT then
-		 * dont enable the breakpoints
-		 */
-		if (options.libcalls) {
-			a = ptrace(PTRACE_PEEKTEXT, proc->pid,
-				   sym2addr(proc, proc->list_of_symbols),
-				   0);
-			if (a == 0x0)
-				return;
-		}
-#endif
 
-		debug(1, "Enabling breakpoints for pid %u...", proc->pid);
-		if (proc->breakpoints) {
-			dict_apply_to_all(proc->breakpoints, enable_bp_cb,
-					  proc);
-		}
-#ifdef __mips__
-		{
-			/*
-			 * I'm sure there is a nicer way to do this. We need to
-			 * insert breakpoints _after_ the child has been started.
-			 */
-			struct library_symbol *sym;
-			struct library_symbol *new_sym;
-			sym=proc->list_of_symbols;
-			while(sym){
-				void *addr= sym2addr(proc,sym);
-				if(!addr){
-					sym=sym->next;
-					continue;
-				}
-				if(dict_find_entry(proc->breakpoints,addr)){
-					sym=sym->next;
-					continue;
-				}
-				debug(2,"inserting bp %p %s",addr,sym->name);
-				new_sym=malloc(sizeof(*new_sym));
-				memcpy(new_sym,sym,sizeof(*new_sym));
-				new_sym->next=proc->list_of_symbols;
-				proc->list_of_symbols=new_sym;
-				insert_breakpoint(proc, addr, new_sym);
-				sym=sym->next;
-			}
-		}
-#endif
+	debug(1, "Enabling breakpoints for pid %u...", proc->pid);
+	if (proc->breakpoints) {
+		dict_apply_to_all(proc->breakpoints, enable_bp_cb,
+				  proc);
 	}
-	proc->breakpoints_enabled = 1;
 }
 
 static void
-disable_bp_cb(void *addr, void *sbp, void *proc) {
+disable_bp_cb(void *addr, void *sbp, void *proc)
+{
 	debug(DEBUG_FUNCTION, "disable_bp_cb(pid=%d)", ((Process *)proc)->pid);
-	if (((Breakpoint *)sbp)->enabled) {
-		disable_breakpoint(((Process *)proc)->pid, sbp);
-	}
+	if (((struct breakpoint *)sbp)->enabled)
+		disable_breakpoint(proc, sbp);
 }
 
 void
 disable_all_breakpoints(Process *proc) {
 	debug(DEBUG_FUNCTION, "disable_all_breakpoints(pid=%d)", proc->pid);
-	if (proc->breakpoints_enabled) {
-		debug(1, "Disabling breakpoints for pid %u...", proc->pid);
-		dict_apply_to_all(proc->breakpoints, disable_bp_cb, proc);
-	}
-	proc->breakpoints_enabled = 0;
+	assert(proc->leader == proc);
+	dict_apply_to_all(proc->breakpoints, disable_bp_cb, proc);
 }
 
+/* XXX This is not currently properly supported.  On clone, this is
+ * just sliced.  Hopefully at the point that clone is done, this
+ * breakpoint is not necessary anymore.  If this use case ends up
+ * being important, we need to add a clone and destroy callbacks to
+ * breakpoints, and we should also probably drop arch_breakpoint_data
+ * so that we don't end up with two different customization mechanisms
+ * for one structure.  */
+struct entry_breakpoint {
+	struct breakpoint super;
+	arch_addr_t dyn_addr;
+};
+
 static void
-free_bp_cb(void *addr, void *sbp, void *data) {
-	debug(DEBUG_FUNCTION, "free_bp_cb(sbp=%p)", sbp);
-	assert(sbp);
-	free(sbp);
+entry_breakpoint_on_hit(struct breakpoint *a, struct Process *proc)
+{
+	struct entry_breakpoint *bp = (void *)a;
+	if (proc == NULL || proc->leader == NULL)
+		return;
+	arch_addr_t dyn_addr = bp->dyn_addr;
+	delete_breakpoint(proc, bp->super.addr);
+	linkmap_init(proc, dyn_addr);
+	arch_dynlink_done(proc);
 }
 
-void
-breakpoints_init(Process *proc) {
-	struct library_symbol *sym;
+int
+entry_breakpoint_init(struct Process *proc,
+		      struct entry_breakpoint *bp, arch_addr_t addr,
+		      struct library *lib)
+{
+	assert(addr != 0);
+	int err = breakpoint_init(&bp->super, proc, addr, NULL);
+	if (err < 0)
+		return err;
 
+	static struct bp_callbacks entry_callbacks = {
+		.on_hit = entry_breakpoint_on_hit,
+	};
+	bp->super.cbs = &entry_callbacks;
+	bp->dyn_addr = lib->dyn_addr;
+	return 0;
+}
+
+int
+breakpoints_init(Process *proc)
+{
 	debug(DEBUG_FUNCTION, "breakpoints_init(pid=%d)", proc->pid);
-	if (proc->breakpoints) {	/* let's remove that struct */
-		dict_apply_to_all(proc->breakpoints, free_bp_cb, NULL);
-		dict_clear(proc->breakpoints);
-		proc->breakpoints = NULL;
-	}
-	proc->breakpoints = dict_init(dict_key2hash_int, dict_key_cmp_int);
-
-	if (options.libcalls && proc->filename) {
-		/* FIXME: memory leak when called by exec(): */
-		proc->list_of_symbols = read_elf(proc);
-		if (opt_e) {
-			struct library_symbol **tmp1 = &(proc->list_of_symbols);
-			while (*tmp1) {
-				struct opt_e_t *tmp2 = opt_e;
-				int keep = !opt_e_enable;
-
-				while (tmp2) {
-					if (!strcmp((*tmp1)->name, tmp2->name)) {
-						keep = opt_e_enable;
-					}
-					tmp2 = tmp2->next;
-				}
-				if (!keep) {
-					*tmp1 = (*tmp1)->next;
-				} else {
-					tmp1 = &((*tmp1)->next);
-				}
-			}
+
+	/* XXX breakpoint dictionary should be initialized
+	 * outside.  Here we just put in breakpoints.  */
+	assert(proc->breakpoints != NULL);
+
+	/* Only the thread group leader should hold the breakpoints.  */
+	assert(proc->leader == proc);
+
+	/* N.B. the following used to be conditional on this, and
+	 * maybe it still needs to be.  */
+	assert(proc->filename != NULL);
+
+	struct library *lib = ltelf_read_main_binary(proc, proc->filename);
+	struct entry_breakpoint *entry_bp = NULL;
+	int bp_state = 0;
+	int result = -1;
+	switch (lib != NULL) {
+	fail:
+		switch (bp_state) {
+		case 2:
+			proc_remove_library(proc, lib);
+			proc_remove_breakpoint(proc, &entry_bp->super);
+		case 1:
+			breakpoint_destroy(&entry_bp->super);
 		}
-	} else {
-		proc->list_of_symbols = NULL;
+		library_destroy(lib);
+		free(entry_bp);
+	case 0:
+		return result;
 	}
-	for (sym = proc->list_of_symbols; sym; sym = sym->next) {
-		/* proc->pid==0 delays enabling. */
-		insert_breakpoint(proc, sym2addr(proc, sym), sym);
-	}
-	proc->callstack_depth = 0;
-	proc->breakpoints_enabled = -1;
-}
 
-void
-reinitialize_breakpoints(Process *proc) {
-	struct library_symbol *sym;
-
-	debug(DEBUG_FUNCTION, "reinitialize_breakpoints(pid=%d)", proc->pid);
-
-	sym = proc->list_of_symbols;
-
-	while (sym) {
-		if (sym->needs_init) {
-			insert_breakpoint(proc, sym2addr(proc, sym),
-					  sym);
-			if (sym->needs_init && !sym->is_weak) {
-				fprintf(stderr,
-					"could not re-initialize breakpoint for \"%s\" in file \"%s\"\n",
-					sym->name, proc->filename);
-				exit(1);
-			}
-		}
-		sym = sym->next;
+	entry_bp = malloc(sizeof(*entry_bp));
+	if (entry_bp == NULL
+	    || (entry_breakpoint_init(proc, entry_bp,
+				      lib->entry, lib)) < 0) {
+		fprintf(stderr,
+			"Couldn't initialize entry breakpoint for PID %d.\n"
+			"Some tracing events may be missed.\n", proc->pid);
+		free(entry_bp);
+
+	} else {
+		++bp_state;
+
+		if ((result = proc_add_breakpoint(proc, &entry_bp->super)) < 0)
+			goto fail;
+		++bp_state;
+
+		if ((result = breakpoint_turn_on(&entry_bp->super, proc)) < 0)
+			goto fail;
 	}
+	proc_add_library(proc, lib);
+
+	proc->callstack_depth = 0;
+	return 0;
 }