diff options
Diffstat (limited to 'src/libdwfl/dwfl_frame.c')
| -rw-r--r-- | src/libdwfl/dwfl_frame.c | 474 |
1 files changed, 474 insertions, 0 deletions
diff --git a/src/libdwfl/dwfl_frame.c b/src/libdwfl/dwfl_frame.c new file mode 100644 index 00000000..f6f86c0d --- /dev/null +++ b/src/libdwfl/dwfl_frame.c @@ -0,0 +1,474 @@ +/* Get Dwarf Frame state for target PID or core file. + Copyright (C) 2013, 2014 Red Hat, Inc. + This file is part of elfutils. + + This file is free software; you can redistribute it and/or modify + it under the terms of either + + * the GNU Lesser General Public License as published by the Free + Software Foundation; either version 3 of the License, or (at + your option) any later version + + or + + * 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 + + or both in parallel, as here. + + elfutils 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 copies of the GNU General Public License and + the GNU Lesser General Public License along with this program. If + not, see <http://www.gnu.org/licenses/>. */ + +#include "libdwflP.h" +#include <sys/ptrace.h> +#include <unistd.h> + +/* Set STATE->pc_set from STATE->regs according to the backend. Return true on + success, false on error. */ +static bool +state_fetch_pc (Dwfl_Frame *state) +{ + switch (state->pc_state) + { + case DWFL_FRAME_STATE_PC_SET: + return true; + case DWFL_FRAME_STATE_PC_UNDEFINED: + abort (); + case DWFL_FRAME_STATE_ERROR: + { + Ebl *ebl = state->thread->process->ebl; + Dwarf_CIE abi_info; + if (ebl_abi_cfi (ebl, &abi_info) != 0) + { + __libdwfl_seterrno (DWFL_E_LIBEBL); + return false; + } + unsigned ra = abi_info.return_address_register; + /* dwarf_frame_state_reg_is_set is not applied here. */ + if (ra >= ebl_frame_nregs (ebl)) + { + __libdwfl_seterrno (DWFL_E_LIBEBL_BAD); + return false; + } + state->pc = state->regs[ra]; + state->pc_state = DWFL_FRAME_STATE_PC_SET; + } + return true; + } + abort (); +} + +/* Do not call it on your own, to be used by thread_* functions only. */ + +static void +state_free (Dwfl_Frame *state) +{ + Dwfl_Thread *thread = state->thread; + assert (thread->unwound == state); + thread->unwound = state->unwound; + free (state); +} + +static void +thread_free_all_states (Dwfl_Thread *thread) +{ + while (thread->unwound) + state_free (thread->unwound); +} + +static Dwfl_Frame * +state_alloc (Dwfl_Thread *thread) +{ + assert (thread->unwound == NULL); + Ebl *ebl = thread->process->ebl; + size_t nregs = ebl_frame_nregs (ebl); + if (nregs == 0) + return NULL; + assert (nregs < sizeof (((Dwfl_Frame *) NULL)->regs_set) * 8); + Dwfl_Frame *state = malloc (sizeof (*state) + sizeof (*state->regs) * nregs); + if (state == NULL) + return NULL; + state->thread = thread; + state->signal_frame = false; + state->initial_frame = true; + state->pc_state = DWFL_FRAME_STATE_ERROR; + memset (state->regs_set, 0, sizeof (state->regs_set)); + thread->unwound = state; + state->unwound = NULL; + return state; +} + +void +internal_function +__libdwfl_process_free (Dwfl_Process *process) +{ + Dwfl *dwfl = process->dwfl; + if (process->callbacks->detach != NULL) + process->callbacks->detach (dwfl, process->callbacks_arg); + assert (dwfl->process == process); + dwfl->process = NULL; + if (process->ebl_close) + ebl_closebackend (process->ebl); + free (process); + dwfl->attacherr = DWFL_E_NOERROR; +} + +/* Allocate new Dwfl_Process for DWFL. */ +static void +process_alloc (Dwfl *dwfl) +{ + Dwfl_Process *process = malloc (sizeof (*process)); + if (process == NULL) + return; + process->dwfl = dwfl; + dwfl->process = process; +} + +bool +dwfl_attach_state (Dwfl *dwfl, Elf *elf, pid_t pid, + const Dwfl_Thread_Callbacks *thread_callbacks, void *arg) +{ + if (dwfl->process != NULL) + { + __libdwfl_seterrno (DWFL_E_ATTACH_STATE_CONFLICT); + return false; + } + + /* Reset any previous error, we are just going to try again. */ + dwfl->attacherr = DWFL_E_NOERROR; + if (thread_callbacks == NULL || thread_callbacks->next_thread == NULL + || thread_callbacks->set_initial_registers == NULL) + { + dwfl->attacherr = DWFL_E_INVALID_ARGUMENT; + fail: + dwfl->attacherr = __libdwfl_canon_error (dwfl->attacherr); + __libdwfl_seterrno (dwfl->attacherr); + return false; + } + + Ebl *ebl; + bool ebl_close; + if (elf != NULL) + { + ebl = ebl_openbackend (elf); + ebl_close = true; + } + else + { + ebl = NULL; + for (Dwfl_Module *mod = dwfl->modulelist; mod != NULL; mod = mod->next) + { + /* Reading of the vDSO or (deleted) modules may fail as + /proc/PID/mem is unreadable without PTRACE_ATTACH and + we may not be PTRACE_ATTACH-ed now. MOD would not be + re-read later to unwind it when we are already + PTRACE_ATTACH-ed to PID. This happens when this function + is called from dwfl_linux_proc_attach with elf == NULL. + __libdwfl_module_getebl will call __libdwfl_getelf which + will call the find_elf callback. */ + if (strncmp (mod->name, "[vdso: ", 7) == 0 + || strcmp (strrchr (mod->name, ' ') ?: "", + " (deleted)") == 0) + continue; + Dwfl_Error error = __libdwfl_module_getebl (mod); + if (error != DWFL_E_NOERROR) + continue; + ebl = mod->ebl; + break; + } + ebl_close = false; + } + if (ebl == NULL) + { + /* Not identified EBL from any of the modules. */ + dwfl->attacherr = DWFL_E_PROCESS_NO_ARCH; + goto fail; + } + process_alloc (dwfl); + Dwfl_Process *process = dwfl->process; + if (process == NULL) + { + if (ebl_close) + ebl_closebackend (ebl); + dwfl->attacherr = DWFL_E_NOMEM; + goto fail; + } + process->ebl = ebl; + process->ebl_close = ebl_close; + process->pid = pid; + process->callbacks = thread_callbacks; + process->callbacks_arg = arg; + return true; +} +INTDEF(dwfl_attach_state) + +pid_t +dwfl_pid (Dwfl *dwfl) +{ + if (dwfl->attacherr != DWFL_E_NOERROR) + { + __libdwfl_seterrno (dwfl->attacherr); + return -1; + } + + if (dwfl->process == NULL) + { + __libdwfl_seterrno (DWFL_E_NO_ATTACH_STATE); + return -1; + } + return dwfl->process->pid; +} +INTDEF(dwfl_pid) + +Dwfl * +dwfl_thread_dwfl (Dwfl_Thread *thread) +{ + return thread->process->dwfl; +} +INTDEF(dwfl_thread_dwfl) + +pid_t +dwfl_thread_tid (Dwfl_Thread *thread) +{ + return thread->tid; +} +INTDEF(dwfl_thread_tid) + +Dwfl_Thread * +dwfl_frame_thread (Dwfl_Frame *state) +{ + return state->thread; +} +INTDEF(dwfl_frame_thread) + +int +dwfl_getthreads (Dwfl *dwfl, int (*callback) (Dwfl_Thread *thread, void *arg), + void *arg) +{ + if (dwfl->attacherr != DWFL_E_NOERROR) + { + __libdwfl_seterrno (dwfl->attacherr); + return -1; + } + + Dwfl_Process *process = dwfl->process; + if (process == NULL) + { + __libdwfl_seterrno (DWFL_E_NO_ATTACH_STATE); + return -1; + } + + Dwfl_Thread thread; + thread.process = process; + thread.unwound = NULL; + thread.callbacks_arg = NULL; + for (;;) + { + thread.tid = process->callbacks->next_thread (dwfl, + process->callbacks_arg, + &thread.callbacks_arg); + if (thread.tid < 0) + { + Dwfl_Error saved_errno = dwfl_errno (); + thread_free_all_states (&thread); + __libdwfl_seterrno (saved_errno); + return -1; + } + if (thread.tid == 0) + { + thread_free_all_states (&thread); + __libdwfl_seterrno (DWFL_E_NOERROR); + return 0; + } + int err = callback (&thread, arg); + if (err != DWARF_CB_OK) + { + thread_free_all_states (&thread); + return err; + } + assert (thread.unwound == NULL); + } + /* NOTREACHED */ +} +INTDEF(dwfl_getthreads) + +struct one_arg +{ + pid_t tid; + bool seen; + int (*callback) (Dwfl_Thread *thread, void *arg); + void *arg; + int ret; +}; + +static int +get_one_thread_cb (Dwfl_Thread *thread, void *arg) +{ + struct one_arg *oa = (struct one_arg *) arg; + if (! oa->seen && INTUSE(dwfl_thread_tid) (thread) == oa->tid) + { + oa->seen = true; + oa->ret = oa->callback (thread, oa->arg); + return DWARF_CB_ABORT; + } + + return DWARF_CB_OK; +} + +/* Note not currently exported, will be when there are more Dwfl_Thread + properties to query. Use dwfl_getthread_frames for now directly. */ +static int +getthread (Dwfl *dwfl, pid_t tid, + int (*callback) (Dwfl_Thread *thread, void *arg), + void *arg) +{ + if (dwfl->attacherr != DWFL_E_NOERROR) + { + __libdwfl_seterrno (dwfl->attacherr); + return -1; + } + + Dwfl_Process *process = dwfl->process; + if (process == NULL) + { + __libdwfl_seterrno (DWFL_E_NO_ATTACH_STATE); + return -1; + } + + if (process->callbacks->get_thread != NULL) + { + Dwfl_Thread thread; + thread.process = process; + thread.unwound = NULL; + thread.callbacks_arg = NULL; + + if (process->callbacks->get_thread (dwfl, tid, process->callbacks_arg, + &thread.callbacks_arg)) + { + int err; + thread.tid = tid; + err = callback (&thread, arg); + thread_free_all_states (&thread); + return err; + } + + return -1; + } + + struct one_arg oa = { .tid = tid, .callback = callback, + .arg = arg, .seen = false }; + int err = INTUSE(dwfl_getthreads) (dwfl, get_one_thread_cb, &oa); + + if (err == DWARF_CB_ABORT && oa.seen) + return oa.ret; + + if (err == DWARF_CB_OK && ! oa.seen) + { + errno = ESRCH; + __libdwfl_seterrno (DWFL_E_ERRNO); + return -1; + } + + return err; +} + +struct one_thread +{ + int (*callback) (Dwfl_Frame *frame, void *arg); + void *arg; +}; + +static int +get_one_thread_frames_cb (Dwfl_Thread *thread, void *arg) +{ + struct one_thread *ot = (struct one_thread *) arg; + return INTUSE(dwfl_thread_getframes) (thread, ot->callback, ot->arg); +} + +int +dwfl_getthread_frames (Dwfl *dwfl, pid_t tid, + int (*callback) (Dwfl_Frame *frame, void *arg), + void *arg) +{ + struct one_thread ot = { .callback = callback, .arg = arg }; + return getthread (dwfl, tid, get_one_thread_frames_cb, &ot); +} +INTDEF(dwfl_getthread_frames) + +int +dwfl_thread_getframes (Dwfl_Thread *thread, + int (*callback) (Dwfl_Frame *state, void *arg), + void *arg) +{ + if (thread->unwound != NULL) + { + /* We had to be called from inside CALLBACK. */ + __libdwfl_seterrno (DWFL_E_ATTACH_STATE_CONFLICT); + return -1; + } + Ebl *ebl = thread->process->ebl; + if (ebl_frame_nregs (ebl) == 0) + { + __libdwfl_seterrno (DWFL_E_NO_UNWIND); + return -1; + } + if (state_alloc (thread) == NULL) + { + __libdwfl_seterrno (DWFL_E_NOMEM); + return -1; + } + Dwfl_Process *process = thread->process; + if (! process->callbacks->set_initial_registers (thread, + thread->callbacks_arg)) + { + thread_free_all_states (thread); + return -1; + } + if (! state_fetch_pc (thread->unwound)) + { + if (process->callbacks->thread_detach) + process->callbacks->thread_detach (thread, thread->callbacks_arg); + thread_free_all_states (thread); + return -1; + } + + Dwfl_Frame *state; + do + { + state = thread->unwound; + int err = callback (state, arg); + if (err != DWARF_CB_OK) + { + if (process->callbacks->thread_detach) + process->callbacks->thread_detach (thread, thread->callbacks_arg); + thread_free_all_states (thread); + return err; + } + __libdwfl_frame_unwind (state); + /* The old frame is no longer needed. */ + state_free (thread->unwound); + state = thread->unwound; + } + while (state && state->pc_state == DWFL_FRAME_STATE_PC_SET); + + Dwfl_Error err = dwfl_errno (); + if (process->callbacks->thread_detach) + process->callbacks->thread_detach (thread, thread->callbacks_arg); + if (state == NULL || state->pc_state == DWFL_FRAME_STATE_ERROR) + { + thread_free_all_states (thread); + __libdwfl_seterrno (err); + return -1; + } + assert (state->pc_state == DWFL_FRAME_STATE_PC_UNDEFINED); + thread_free_all_states (thread); + return 0; +} +INTDEF(dwfl_thread_getframes) |