void
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) + strlen(sym->name) + 1);
memcpy(new_sym,sym,sizeof(*new_sym) + strlen(sym->name) + 1);
new_sym->next=proc->list_of_symbols;
proc->list_of_symbols=new_sym;
insert_breakpoint(proc, addr, new_sym);
sym=sym->next;
}
}
#endif
}
proc->breakpoints_enabled = 1;
}
static enum callback_status
cb_enable_breakpoint_sym(struct library_symbol *libsym, void *data)
{
struct Process *proc = data;
arch_addr_t bp_addr;
if (!libsym->arch.gotonly)
return CBS_CONT;
/* Update state. */
bp_addr = sym2addr(proc, libsym);
/* XXX The cast to uintptr_t should be removed when
* arch_addr_t becomes integral type. keywords: double cast. */
libsym->arch.resolved_addr = (uintptr_t) bp_addr;
if (libsym->arch.resolved_addr == 0)
/* FIXME: What does this mean? */
return CBS_CONT;
libsym->arch.type = MIPS_PLT_RESOLVED;
/* Now, activate the symbol causing a breakpoint to be added. */
if (proc_activate_delayed_symbol(proc, libsym) < 0) {
fprintf(stderr, "Failed to activate delayed sym %s\n",
libsym->name);
}
return CBS_CONT;
}
int
linkmap_init(Process *proc, struct ltelf *lte) {
void *dbg_addr = NULL, *dyn_addr = GELF_ADDR_CAST(lte->dyn_addr);
struct r_debug *rdbg = NULL;
struct cb_data data;
debug(DEBUG_FUNCTION, "linkmap_init()");
if (find_dynamic_entry_addr(proc, dyn_addr, DT_DEBUG, &dbg_addr) == -1) {
debug(2, "Couldn't find debug structure!");
return -1;
}
proc->debug = dbg_addr;
if (!(rdbg = load_debug_struct(proc))) {
debug(2, "No debug structure or no memory to allocate one!");
return -1;
}
data.lte = lte;
add_library_symbol(rdbg->r_brk, "", &library_symbols, LS_TOPLT_NONE, 0);
insert_breakpoint(proc, sym2addr(proc, library_symbols),
library_symbols, 1);
crawl_linkmap(proc, rdbg, hook_libdl_cb, &data);
free(rdbg);
return 0;
}
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)
{
char *name = NULL;
int sym_index = ndx + lte->arch.mips_gotsym;
struct library_symbol *libsym = malloc(sizeof(*libsym));
if (libsym == NULL)
return plt_fail;
GElf_Addr addr = arch_plt_sym_val(lte, sym_index, 0);
name = strdup(a_name);
if (name == NULL) {
fprintf(stderr, "%s: failed %s(%#llx): %s\n", __func__,
name, addr, strerror(errno));
goto fail;
}
/* XXX The double cast should be removed when
* arch_addr_t becomes integral type. */
if (library_symbol_init(libsym,
(arch_addr_t) (uintptr_t) addr,
name, 1, LS_TOPLT_EXEC) < 0) {
fprintf(stderr, "%s: failed %s : %llx\n", __func__, name, addr);
goto fail;
}
arch_addr_t bp_addr = sym2addr(proc, libsym);
/* XXX This cast should be removed when
* arch_addr_t becomes integral type. keywords: double cast. */
libsym->arch.stub_addr = (uintptr_t) bp_addr;
if (bp_addr == 0) {
/* Function pointers without PLT entries. */
libsym->plt_type = LS_TOPLT_NONE;
libsym->arch.gotonly = 1;
libsym->arch.type = MIPS_PLT_UNRESOLVED;
/* Delay breakpoint activation until the symbol gets
* resolved. */
libsym->delayed = 1;
} else if (mips_elf_is_cpic(lte->ehdr.e_flags)) {
libsym->arch.pltalways = 1;
}
*ret = libsym;
return plt_ok;
fail:
free(name);
free(libsym);
return plt_fail;
}
static void
linkmap_add_cb(void *data) { //const char *lib_name, ElfW(Addr) addr) {
size_t i = 0;
struct cb_data *lm_add = data;
struct ltelf lte;
struct opt_x_t *xptr;
debug(DEBUG_FUNCTION, "linkmap_add_cb");
/*
XXX
iterate through library[i]'s to see if this lib is in the list.
if not, add it
*/
for(;i < library_num;i++) {
if (strcmp(library[i], lm_add->lib_name) == 0) {
/* found it, so its not new */
return;
}
}
/* new library linked! */
debug(2, "New libdl loaded library found: %s\n", lm_add->lib_name);
if (library_num < MAX_LIBRARIES) {
library[library_num++] = strdup(lm_add->lib_name);
memset(<e, 0, sizeof(struct ltelf));
lte.base_addr = lm_add->addr;
do_init_elf(<e, library[library_num-1]);
/* add bps */
for (xptr = opt_x; xptr; xptr = xptr->next) {
if (xptr->found)
continue;
GElf_Sym sym;
GElf_Addr addr;
if (in_load_libraries(xptr->name, <e, 1, &sym)) {
debug(2, "found symbol %s @ %#" PRIx64
", adding it.",
xptr->name, sym.st_value);
addr = sym.st_value;
add_library_symbol(addr, xptr->name, &library_symbols, LS_TOPLT_NONE, 0);
xptr->found = 1;
insert_breakpoint(lm_add->proc,
sym2addr(lm_add->proc,
library_symbols),
library_symbols, 1);
}
}
do_close_elf(<e);
}
}
/* 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);
}
void
breakpoints_init(Process *proc) {
struct library_symbol *sym;
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);
}
}
}
} else {
proc->list_of_symbols = NULL;
}
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;
}
}
static void
handle_breakpoint(Event *event) {
int i, j;
Breakpoint *sbp;
Process *leader = event->proc->leader;
/* The leader has terminated. */
if (leader == NULL) {
continue_process(event->proc->pid);
return;
}
debug(DEBUG_FUNCTION, "handle_breakpoint(pid=%d, addr=%p)", event->proc->pid, event->e_un.brk_addr);
debug(2, "event: breakpoint (%p)", event->e_un.brk_addr);
#ifdef __powerpc__
/* Need to skip following NOP's to prevent a fake function from being stacked. */
long stub_addr = (long) get_count_register(event->proc);
Breakpoint *stub_bp = NULL;
char nop_instruction[] = PPC_NOP;
stub_bp = address2bpstruct(leader, event->e_un.brk_addr);
if (stub_bp) {
unsigned char *bp_instruction = stub_bp->orig_value;
if (memcmp(bp_instruction, nop_instruction,
PPC_NOP_LENGTH) == 0) {
if (stub_addr != (long) event->e_un.brk_addr) {
set_instruction_pointer (event->proc, event->e_un.brk_addr + 4);
continue_process(event->proc->pid);
return;
}
}
}
#endif
for (i = event->proc->callstack_depth - 1; i >= 0; i--) {
if (event->e_un.brk_addr ==
event->proc->callstack[i].return_addr) {
#ifdef __powerpc__
/*
* PPC HACK! (XXX FIXME TODO)
* The PLT gets modified during the first call,
* so be sure to re-enable the breakpoint.
*/
unsigned long a;
struct library_symbol *libsym =
event->proc->callstack[i].c_un.libfunc;
void *addr = sym2addr(event->proc, libsym);
if (libsym->plt_type != LS_TOPLT_POINT) {
unsigned char break_insn[] = BREAKPOINT_VALUE;
sbp = address2bpstruct(leader, addr);
assert(sbp);
a = ptrace(PTRACE_PEEKTEXT, event->proc->pid,
addr);
if (memcmp(&a, break_insn, BREAKPOINT_LENGTH)) {
sbp->enabled--;
insert_breakpoint(event->proc, addr,
libsym, 1);
}
} else {
sbp = dict_find_entry(leader->breakpoints, addr);
/* On powerpc, the breakpoint address
may end up being actual entry point
of the library symbol, not the PLT
address we computed. In that case,
sbp is NULL. */
if (sbp == NULL || addr != sbp->addr) {
insert_breakpoint(event->proc, addr,
libsym, 1);
}
}
#elif defined(__mips__)
void *addr = NULL;
struct library_symbol *sym= event->proc->callstack[i].c_un.libfunc;
struct library_symbol *new_sym;
assert(sym);
addr = sym2addr(event->proc, sym);
sbp = dict_find_entry(leader->breakpoints, addr);
if (sbp) {
if (addr != sbp->addr) {
insert_breakpoint(event->proc, addr, sym, 1);
}
} else {
new_sym=malloc(sizeof(*new_sym) + strlen(sym->name) + 1);
memcpy(new_sym,sym,sizeof(*new_sym) + strlen(sym->name) + 1);
new_sym->next = leader->list_of_symbols;
leader->list_of_symbols = new_sym;
insert_breakpoint(event->proc, addr, new_sym, 1);
}
#endif
for (j = event->proc->callstack_depth - 1; j > i; j--) {
callstack_pop(event->proc);
}
if (event->proc->state != STATE_IGNORED) {
if (opt_T || options.summary) {
calc_time_spent(event->proc);
}
}
event->proc->return_addr = event->e_un.brk_addr;
if (event->proc->state != STATE_IGNORED) {
mock_return(LT_TOF_FUNCTIONR, event->proc,
event->proc->callstack[i].c_un.libfunc->name);
output_right(LT_TOF_FUNCTIONR, event->proc,
event->proc->callstack[i].c_un.libfunc->name);
}
callstack_pop(event->proc);
sbp = address2bpstruct(leader, event->e_un.brk_addr);
continue_after_breakpoint(event->proc, sbp);
return;
}
}
if ((sbp = address2bpstruct(leader, event->e_un.brk_addr))) {
if (sbp->libsym == NULL) {
continue_after_breakpoint(event->proc, sbp);
return;
}
if (strcmp(sbp->libsym->name, "") == 0) {
debug(DEBUG_PROCESS, "Hit _dl_debug_state breakpoint!\n");
arch_check_dbg(leader);
}
if (event->proc->state != STATE_IGNORED) {
event->proc->stack_pointer = get_stack_pointer(event->proc);
event->proc->return_addr =
get_return_addr(event->proc, event->proc->stack_pointer);
callstack_push_symfunc(event->proc, sbp->libsym);
output_left(LT_TOF_FUNCTION, event->proc, sbp->libsym->name);
}
#ifdef PLT_REINITALISATION_BP
if (event->proc->need_to_reinitialize_breakpoints
&& (strcmp(sbp->libsym->name, PLTs_initialized_by_here) ==
0))
reinitialize_breakpoints(leader);
#endif
continue_after_breakpoint(event->proc, sbp);
return;
}
if (event->proc->state != STATE_IGNORED && !options.no_plt) {
output_line(event->proc, "unexpected breakpoint at %p",
(void *)event->e_un.brk_addr);
}
continue_process(event->proc->pid);
}
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;
}
