void
delete_breakpoint(struct process *proc, void *addr)
{
debug(DEBUG_FUNCTION, "delete_breakpoint(pid=%d, addr=%p)", proc->pid, addr);
struct 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;
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);
}
}
int
breakpoints_init(struct process *proc)
{
debug(DEBUG_FUNCTION, "breakpoints_init(pid=%d)", proc->pid);
/* 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 ((int)(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);
}
library_destroy(lib);
free(entry_bp);
case 0:
return result;
}
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;
}
/* When functions return we check if the symbol needs an updated
breakpoint with the resolved address. */
void arch_symbol_ret(struct Process *proc, struct library_symbol *libsym)
{
struct breakpoint *bp;
arch_addr_t resolved_addr;
struct Process *leader = proc->leader;
/* Only deal with unresolved symbols. */
if (libsym->arch.type != MIPS_PLT_UNRESOLVED)
return;
/* Get out if we are always using the PLT. */
if (libsym->arch.pltalways)
return;
resolved_addr = sym2addr(proc, libsym);
libsym->arch.resolved_addr = (uintptr_t) resolved_addr;
libsym->arch.type = MIPS_PLT_RESOLVED;
if (libsym->arch.stub_addr == libsym->arch.resolved_addr) {
/* Prelinked symbol. No need to add new breakpoint. */
return;
}
bp = malloc(sizeof (*bp));
if (bp == NULL) {
fprintf(stderr, "Failed to allocate bp for %s\n",
libsym->name);
return;
}
if (breakpoint_init(bp, leader, resolved_addr, libsym) < 0)
goto err;
if (proc_add_breakpoint(leader, bp) < 0) {
breakpoint_destroy(bp);
goto err;
}
if (breakpoint_turn_on(bp, leader) < 0) {
proc_remove_breakpoint(leader, bp);
breakpoint_destroy(bp);
goto err;
}
return;
err:
free(bp);
}
struct breakpoint *
insert_breakpoint(struct process *proc, void *addr,
struct library_symbol *libsym)
{
struct 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;
}
}
if (breakpoint_turn_on(sbp, proc) < 0) {
proc_remove_breakpoint(leader, sbp);
goto fail;
}
return sbp;
}
static int
breakpoint_for_symbol(struct library_symbol *libsym, struct Process *proc)
{
arch_addr_t bp_addr;
assert(proc->leader == proc);
/* Don't enable latent or delayed symbols. */
if (libsym->latent || libsym->delayed) {
debug(DEBUG_FUNCTION,
"delayed and/or latent breakpoint pid=%d, %s@%p",
proc->pid, libsym->name, libsym->enter_addr);
return 0;
}
bp_addr = sym2addr(proc, libsym);
/* If there is an artificial breakpoint on the same address,
* its libsym will be NULL, and we can smuggle our libsym
* there. That artificial breakpoint is there presumably for
* the callbacks, which we don't touch. If there is a real
* breakpoint, then this is a bug. ltrace-elf.c should filter
* symbols and ignore extra symbol aliases.
*
* The other direction is more complicated and currently not
* supported. If a breakpoint has custom callbacks, it might
* be also custom-allocated, and we would really need to swap
* the two: delete the one now in the dictionary, swap values
* around, and put the new breakpoint back in. */
struct breakpoint *bp = dict_find_entry(proc->breakpoints,
bp_addr);
if (bp != NULL) {
/* MIPS backend makes duplicate requests. This is
* likely a bug in the backend. Currently there's no
* point assigning more than one symbol to a
* breakpoint, because when it hits, we won't know
* what to print out. But it's easier to fix it here
* before someone who understands MIPS has the time to
* look into it. So turn the sanity check off on
* MIPS. References:
*
* http://lists.alioth.debian.org/pipermail/ltrace-devel/2012-November/000764.html
* http://lists.alioth.debian.org/pipermail/ltrace-devel/2012-November/000770.html
*/
#ifndef __mips__
assert(bp->libsym == NULL);
bp->libsym = libsym;
#endif
return 0;
}
bp = malloc(sizeof(*bp));
if (bp == NULL
|| breakpoint_init(bp, proc, bp_addr, libsym) < 0) {
fail:
free(bp);
return -1;
}
if (proc_add_breakpoint(proc, bp) < 0) {
breakpoint_destroy(bp);
goto fail;
}
if (breakpoint_turn_on(bp, proc) < 0) {
proc_remove_breakpoint(proc, bp);
breakpoint_destroy(bp);
goto fail;
}
return 0;
}