| /*--------------------------------------------------------------------*/ |
| /*--- Implementation of vgdb invoker subsystem via ptrace() calls. ---*/ |
| /*--------------------------------------------------------------------*/ |
| |
| /* |
| This file is part of Valgrind, a dynamic binary instrumentation |
| framework. |
| |
| Copyright (C) 2011-2013 Philippe Waroquiers |
| |
| 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., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307, USA. |
| |
| The GNU General Public License is contained in the file COPYING. |
| */ |
| |
| #include "config.h" |
| |
| #include "vgdb.h" |
| #include "pub_core_threadstate.h" |
| |
| #include <alloca.h> |
| #include <assert.h> |
| #include <errno.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <sys/ptrace.h> |
| #include <sys/time.h> |
| #include <sys/user.h> |
| #include <sys/wait.h> |
| |
| #ifdef PTRACE_GETREGSET |
| // TBD: better have a configure test instead ? |
| #define HAVE_PTRACE_GETREGSET |
| |
| // A bi-arch build using PTRACE_GET/SETREGSET needs |
| // some conversion code for register structures. |
| // So, better do not use PTRACE_GET/SETREGSET |
| // Rather we use PTRACE_GETREGS or PTRACE_PEEKUSER. |
| |
| // The only platform on which we must use PTRACE_GETREGSET is arm64. |
| // The resulting vgdb cannot work in a bi-arch setup. |
| // -1 means we will check that PTRACE_GETREGSET works. |
| # if defined(VGA_arm64) |
| #define USE_PTRACE_GETREGSET |
| # endif |
| #endif |
| |
| #include <sys/uio.h> |
| #include <elf.h> |
| |
| #include <sys/procfs.h> |
| |
| #if defined(VGA_s390x) |
| /* RHEL 5 uses glibc 2.3.4 which does not define PTRACE_GETSIGINFO */ |
| # ifndef PTRACE_GETSIGINFO |
| # define PTRACE_GETSIGINFO 0x4202 |
| # endif |
| #endif |
| |
| #if VEX_HOST_WORDSIZE == 8 |
| typedef Addr64 CORE_ADDR; |
| #elif VEX_HOST_WORDSIZE == 4 |
| typedef Addr32 CORE_ADDR; |
| #else |
| # error "unexpected wordsize" |
| #endif |
| |
| #if VEX_HOST_WORDSIZE == 8 |
| typedef Addr64 PTRACE_XFER_TYPE; |
| typedef void* PTRACE_ARG3_TYPE; |
| #elif VEX_HOST_WORDSIZE == 4 |
| typedef Addr32 PTRACE_XFER_TYPE; |
| typedef void* PTRACE_ARG3_TYPE; |
| #else |
| # error "unexpected wordsize" |
| #endif |
| |
| // if > 0, pid for which registers have to be restored. |
| // if == 0, means we have not yet called setregs (or have already |
| // restored the registers). |
| static int pid_of_save_regs = 0; |
| /* True if we have continued pid_of_save_regs after PTRACE_ATTACH. */ |
| static Bool pid_of_save_regs_continued = False; |
| // When setregs has been called to change the registers of pid_of_save_regs, |
| // vgdb cannot transmit the signals intercepted during ptrace. |
| // So, we queue them, and will deliver them when detaching. |
| // See function waitstopped for more info. |
| static int signal_queue_sz = 0; |
| static siginfo_t *signal_queue; |
| |
| /* True when loss of connection indicating that the Valgrind |
| process is dying. */ |
| static Bool dying = False; |
| |
| /* ptrace_(read|write)_memory are modified extracts of linux-low.c |
| from gdb 6.6. Copyrighted FSF */ |
| /* Copy LEN bytes from valgrind memory starting at MEMADDR |
| to vgdb memory starting at MYADDR. */ |
| static |
| int ptrace_read_memory (pid_t inferior_pid, CORE_ADDR memaddr, |
| void *myaddr, size_t len) |
| { |
| register int i; |
| /* Round starting address down to longword boundary. */ |
| register CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_XFER_TYPE); |
| /* Round ending address up; get number of longwords that makes. */ |
| register int count |
| = (((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1) |
| / sizeof (PTRACE_XFER_TYPE); |
| /* Allocate buffer of that many longwords. */ |
| register PTRACE_XFER_TYPE *buffer |
| = (PTRACE_XFER_TYPE *) alloca (count * sizeof (PTRACE_XFER_TYPE)); |
| |
| /* Read all the longwords */ |
| for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE)) { |
| errno = 0; |
| buffer[i] = ptrace (PTRACE_PEEKTEXT, inferior_pid, |
| (PTRACE_ARG3_TYPE) addr, 0); |
| if (errno) |
| return errno; |
| } |
| |
| /* Copy appropriate bytes out of the buffer. */ |
| memcpy (myaddr, |
| (char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)), len); |
| |
| return 0; |
| } |
| |
| /* Copy LEN bytes of data from vgdb memory at MYADDR |
| to valgrind memory at MEMADDR. |
| On failure (cannot write the valgrind memory) |
| returns the value of errno. */ |
| __attribute__((unused)) /* not used on all platforms */ |
| static |
| int ptrace_write_memory (pid_t inferior_pid, CORE_ADDR memaddr, |
| const void *myaddr, size_t len) |
| { |
| register int i; |
| /* Round starting address down to longword boundary. */ |
| register CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_XFER_TYPE); |
| /* Round ending address up; get number of longwords that makes. */ |
| register int count |
| = (((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1) |
| / sizeof (PTRACE_XFER_TYPE); |
| /* Allocate buffer of that many longwords. */ |
| register PTRACE_XFER_TYPE *buffer |
| = (PTRACE_XFER_TYPE *) alloca (count * sizeof (PTRACE_XFER_TYPE)); |
| |
| if (debuglevel >= 1) { |
| DEBUG (1, "Writing "); |
| for (i = 0; i < len; i++) |
| PDEBUG (1, "%02x", ((const unsigned char*)myaddr)[i]); |
| PDEBUG(1, " to %p\n", (void *) memaddr); |
| } |
| |
| /* Fill start and end extra bytes of buffer with existing memory data. */ |
| |
| buffer[0] = ptrace (PTRACE_PEEKTEXT, inferior_pid, |
| (PTRACE_ARG3_TYPE) addr, 0); |
| |
| if (count > 1) { |
| buffer[count - 1] |
| = ptrace (PTRACE_PEEKTEXT, inferior_pid, |
| (PTRACE_ARG3_TYPE) (addr + (count - 1) |
| * sizeof (PTRACE_XFER_TYPE)), |
| 0); |
| } |
| |
| /* Copy data to be written over corresponding part of buffer */ |
| |
| memcpy ((char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)), |
| myaddr, len); |
| |
| /* Write the entire buffer. */ |
| |
| for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE)) { |
| errno = 0; |
| ptrace (PTRACE_POKETEXT, inferior_pid, |
| (PTRACE_ARG3_TYPE) addr, buffer[i]); |
| if (errno) |
| return errno; |
| } |
| |
| return 0; |
| } |
| |
| /* subset of VG_(threads) needed for vgdb ptrace. |
| This is initialized when process is attached. */ |
| typedef struct { |
| ThreadStatus status; |
| Int lwpid; |
| } |
| VgdbThreadState; |
| static VgdbThreadState vgdb_threads[VG_N_THREADS]; |
| |
| static const |
| HChar* name_of_ThreadStatus ( ThreadStatus status ) |
| { |
| switch (status) { |
| case VgTs_Empty: return "VgTs_Empty"; |
| case VgTs_Init: return "VgTs_Init"; |
| case VgTs_Runnable: return "VgTs_Runnable"; |
| case VgTs_WaitSys: return "VgTs_WaitSys"; |
| case VgTs_Yielding: return "VgTs_Yielding"; |
| case VgTs_Zombie: return "VgTs_Zombie"; |
| default: return "VgTs_???"; |
| } |
| } |
| |
| static |
| char *status_image (int status) |
| { |
| static char result[256]; |
| int sz = 0; |
| #define APPEND(...) sz += snprintf (result+sz, 256 - sz - 1, __VA_ARGS__) |
| |
| result[0] = 0; |
| |
| if (WIFEXITED(status)) |
| APPEND ("WIFEXITED %d ", WEXITSTATUS(status)); |
| |
| if (WIFSIGNALED(status)) { |
| APPEND ("WIFSIGNALED %d ", WTERMSIG(status)); |
| if (WCOREDUMP(status)) APPEND ("WCOREDUMP "); |
| } |
| |
| if (WIFSTOPPED(status)) |
| APPEND ("WIFSTOPPED %d ", WSTOPSIG(status)); |
| |
| #ifdef WIFCONTINUED |
| if (WIFCONTINUED(status)) |
| APPEND ("WIFCONTINUED "); |
| #endif |
| |
| return result; |
| #undef APPEND |
| } |
| |
| /* Wait till the process pid is reported as stopped with signal_expected. |
| If other signal(s) than signal_expected are received, waitstopped |
| will pass them to pid, waiting for signal_expected to stop pid. |
| Returns True when process is in stopped state with signal_expected. |
| Returns False if a problem was encountered while waiting for pid |
| to be stopped. |
| |
| If pid is reported as being dead/exited, waitstopped will return False. |
| */ |
| static |
| Bool waitstopped (pid_t pid, int signal_expected, const char *msg) |
| { |
| pid_t p; |
| int status = 0; |
| int signal_received; |
| int res; |
| |
| while (1) { |
| DEBUG(1, "waitstopped %s before waitpid signal_expected %d\n", |
| msg, signal_expected); |
| p = waitpid(pid, &status, __WALL); |
| DEBUG(1, "after waitpid pid %d p %d status 0x%x %s\n", pid, p, |
| status, status_image (status)); |
| if (p != pid) { |
| ERROR(errno, "%s waitpid pid %d in waitstopped %d status 0x%x %s\n", |
| msg, pid, p, status, status_image (status)); |
| return False; |
| } |
| |
| if (WIFEXITED(status)) { |
| shutting_down = True; |
| return False; |
| } |
| |
| assert (WIFSTOPPED(status)); |
| signal_received = WSTOPSIG(status); |
| if (signal_received == signal_expected) |
| break; |
| |
| /* pid received a signal which is not the signal we are waiting for. |
| If we have not (yet) changed the registers of the inferior |
| or we have (already) reset them, we can transmit the signal. |
| |
| If we have already set the registers of the inferior, we cannot |
| transmit the signal, as this signal would arrive when the |
| gdbserver code runs. And valgrind only expects signals to |
| arrive in a small code portion around |
| client syscall logic, where signal are unmasked (see e.g. |
| m_syswrap/syscall-x86-linux.S ML_(do_syscall_for_client_WRK). |
| |
| As ptrace is forcing a call to gdbserver by jumping |
| 'out of this region', signals are not masked, but |
| will arrive outside of the allowed/expected code region. |
| So, if we have changed the registers of the inferior, we |
| rather queue the signal to transmit them when detaching, |
| after having restored the registers to the initial values. */ |
| if (pid_of_save_regs) { |
| siginfo_t *newsiginfo; |
| |
| // realloc a bigger queue, and store new signal at the end. |
| // This is not very efficient but we assume not many sigs are queued. |
| signal_queue_sz++; |
| signal_queue = vrealloc(signal_queue, sizeof(siginfo_t) * signal_queue_sz); |
| newsiginfo = signal_queue + (signal_queue_sz - 1); |
| |
| res = ptrace (PTRACE_GETSIGINFO, pid, NULL, newsiginfo); |
| if (res != 0) { |
| ERROR(errno, "PTRACE_GETSIGINFO failed: signal lost !!!!\n"); |
| signal_queue_sz--; |
| } else |
| DEBUG(1, "waitstopped PTRACE_CONT, queuing signal %d" |
| " si_signo %d si_pid %d\n", |
| signal_received, newsiginfo->si_signo, newsiginfo->si_pid); |
| res = ptrace (PTRACE_CONT, pid, NULL, 0); |
| } else { |
| DEBUG(1, "waitstopped PTRACE_CONT with signal %d\n", signal_received); |
| res = ptrace (PTRACE_CONT, pid, NULL, signal_received); |
| } |
| if (res != 0) { |
| ERROR(errno, "waitstopped PTRACE_CONT\n"); |
| return False; |
| } |
| } |
| |
| return True; |
| } |
| |
| /* Stops the given pid, wait for the process to be stopped. |
| Returns True if succesful, False otherwise. |
| msg is used in tracing and error reporting. */ |
| static |
| Bool stop (pid_t pid, const char *msg) |
| { |
| long res; |
| |
| DEBUG(1, "%s SIGSTOP pid %d\n", msg, pid); |
| res = kill (pid, SIGSTOP); |
| if (res != 0) { |
| ERROR(errno, "%s SIGSTOP pid %d %ld\n", msg, pid, res); |
| return False; |
| } |
| |
| return waitstopped (pid, SIGSTOP, msg); |
| |
| } |
| |
| /* Attaches to given pid, wait for the process to be stopped. |
| Returns True if succesful, False otherwise. |
| msg is used in tracing and error reporting. */ |
| static |
| Bool attach (pid_t pid, const char *msg) |
| { |
| long res; |
| static Bool output_error = True; |
| static Bool initial_attach = True; |
| // For a ptrace_scope protected system, we do not want to output |
| // repetitively attach error. We will output once an error |
| // for the initial_attach. Once the 1st attach has succeeded, we |
| // again show all errors. |
| |
| DEBUG(1, "%s PTRACE_ATTACH pid %d\n", msg, pid); |
| res = ptrace (PTRACE_ATTACH, pid, NULL, NULL); |
| if (res != 0) { |
| if (output_error || debuglevel > 0) { |
| ERROR(errno, "%s PTRACE_ATTACH pid %d %ld\n", msg, pid, res); |
| if (initial_attach) |
| output_error = False; |
| } |
| return False; |
| } |
| |
| initial_attach = False; |
| output_error = True; |
| return waitstopped(pid, SIGSTOP, msg); |
| } |
| |
| /* once we are attached to the pid, get the list of threads and stop |
| them all. |
| Returns True if all threads properly suspended, False otherwise. */ |
| static |
| Bool acquire_and_suspend_threads (pid_t pid) |
| { |
| int i; |
| int rw; |
| Bool pid_found = False; |
| Addr vgt; |
| int sz_tst; |
| int off_status; |
| int off_lwpid; |
| int nr_live_threads = 0; |
| |
| if (shared32 != NULL) { |
| vgt = shared32->threads; |
| sz_tst = shared32->sizeof_ThreadState; |
| off_status = shared32->offset_status; |
| off_lwpid = shared32->offset_lwpid; |
| } |
| else if (shared64 != NULL) { |
| vgt = shared64->threads; |
| sz_tst = shared64->sizeof_ThreadState; |
| off_status = shared64->offset_status; |
| off_lwpid = shared64->offset_lwpid; |
| } else { |
| assert (0); |
| } |
| |
| /* note: the entry 0 is unused */ |
| for (i = 1; i < VG_N_THREADS; i++) { |
| vgt += sz_tst; |
| rw = ptrace_read_memory(pid, vgt+off_status, |
| &(vgdb_threads[i].status), |
| sizeof(ThreadStatus)); |
| if (rw != 0) { |
| ERROR(rw, "status ptrace_read_memory\n"); |
| return False; |
| } |
| |
| rw = ptrace_read_memory(pid, vgt+off_lwpid, |
| &(vgdb_threads[i].lwpid), |
| sizeof(Int)); |
| if (rw != 0) { |
| ERROR(rw, "lwpid ptrace_read_memory\n"); |
| return False; |
| } |
| |
| if (vgdb_threads[i].status != VgTs_Empty) { |
| DEBUG(1, "found tid %d status %s lwpid %d\n", |
| i, name_of_ThreadStatus(vgdb_threads[i].status), |
| vgdb_threads[i].lwpid); |
| nr_live_threads++; |
| if (vgdb_threads[i].lwpid <= 1) { |
| if (vgdb_threads[i].lwpid == 0 |
| && vgdb_threads[i].status == VgTs_Init) { |
| DEBUG(1, "not set lwpid tid %d status %s lwpid %d\n", |
| i, name_of_ThreadStatus(vgdb_threads[i].status), |
| vgdb_threads[i].lwpid); |
| } else { |
| ERROR(1, "unexpected lwpid tid %d status %s lwpid %d\n", |
| i, name_of_ThreadStatus(vgdb_threads[i].status), |
| vgdb_threads[i].lwpid); |
| } |
| /* in case we have a VtTs_Init thread with lwpid not yet set, |
| we try again later. */ |
| return False; |
| } |
| if (vgdb_threads[i].lwpid == pid) { |
| assert (!pid_found); |
| assert (i == 1); |
| pid_found = True; |
| } else { |
| if (!attach(vgdb_threads[i].lwpid, "attach_thread")) { |
| ERROR(0, "ERROR attach pid %d tid %d\n", |
| vgdb_threads[i].lwpid, i); |
| return False; |
| } |
| } |
| } |
| } |
| /* If we found no thread, it means the process is stopping, and |
| we better do not force anything to happen during that. */ |
| if (nr_live_threads > 0) |
| return True; |
| else |
| return False; |
| } |
| |
| static |
| void detach_from_all_threads (pid_t pid) |
| { |
| int i; |
| long res; |
| Bool pid_found = False; |
| |
| /* detach from all the threads */ |
| for (i = 1; i < VG_N_THREADS; i++) { |
| if (vgdb_threads[i].status != VgTs_Empty) { |
| if (vgdb_threads[i].status == VgTs_Init |
| && vgdb_threads[i].lwpid == 0) { |
| DEBUG(1, "skipping PTRACE_DETACH pid %d tid %d status %s\n", |
| vgdb_threads[i].lwpid, i, |
| name_of_ThreadStatus (vgdb_threads[i].status)); |
| } else { |
| if (vgdb_threads[i].lwpid == pid) { |
| assert (!pid_found); |
| pid_found = True; |
| } |
| DEBUG(1, "PTRACE_DETACH pid %d tid %d status %s\n", |
| vgdb_threads[i].lwpid, i, |
| name_of_ThreadStatus (vgdb_threads[i].status)); |
| res = ptrace (PTRACE_DETACH, vgdb_threads[i].lwpid, NULL, NULL); |
| if (res != 0) { |
| ERROR(errno, "PTRACE_DETACH pid %d tid %d status %s res %ld\n", |
| vgdb_threads[i].lwpid, i, |
| name_of_ThreadStatus (vgdb_threads[i].status), |
| res); |
| } |
| } |
| } |
| } |
| |
| if (!pid_found && pid) { |
| /* No threads are live. Process is busy stopping. |
| We need to detach from pid explicitely. */ |
| DEBUG(1, "no thread live => PTRACE_DETACH pid %d\n", pid); |
| res = ptrace (PTRACE_DETACH, pid, NULL, NULL); |
| if (res != 0) |
| ERROR(errno, "PTRACE_DETACH pid %d res %ld\n", pid, res); |
| } |
| } |
| |
| # if defined(VGA_arm64) |
| /* arm64 is extra special, old glibc defined kernel user_pt_regs, but |
| newer glibc instead define user_regs_struct. */ |
| # ifdef HAVE_SYS_USER_REGS |
| static struct user_regs_struct user_save; |
| # else |
| static struct user_pt_regs user_save; |
| # endif |
| # else |
| static struct user user_save; |
| # endif |
| // The below indicates if ptrace_getregs (and ptrace_setregs) can be used. |
| // Note that some linux versions are defining PTRACE_GETREGS but using |
| // it gives back EIO. |
| // has_working_ptrace_getregs can take the following values: |
| // -1 : PTRACE_GETREGS is defined |
| // runtime check not yet done. |
| // 0 : PTRACE_GETREGS runtime check has failed. |
| // 1 : PTRACE_GETREGS defined and runtime check ok. |
| #ifdef HAVE_PTRACE_GETREGS |
| static int has_working_ptrace_getregs = -1; |
| #endif |
| // Similar but for PTRACE_GETREGSET |
| #ifdef HAVE_PTRACE_GETREGSET |
| static int has_working_ptrace_getregset = -1; |
| #endif |
| |
| /* Get the registers from pid into regs. |
| regs_bsz value gives the length of *regs. |
| Returns True if all ok, otherwise False. */ |
| static |
| Bool getregs (pid_t pid, void *regs, long regs_bsz) |
| { |
| DEBUG(1, "getregs regs_bsz %ld\n", regs_bsz); |
| # ifdef HAVE_PTRACE_GETREGSET |
| # ifndef USE_PTRACE_GETREGSET |
| if (has_working_ptrace_getregset) |
| DEBUG(1, "PTRACE_GETREGSET defined, not used (yet?) by vgdb\n"); |
| has_working_ptrace_getregset = 0; |
| # endif |
| if (has_working_ptrace_getregset) { |
| // Platforms having GETREGSET |
| long res; |
| elf_gregset_t elf_regs; |
| struct iovec iovec; |
| |
| DEBUG(1, "getregs PTRACE_GETREGSET sizeof(elf_regs) %zu\n", |
| sizeof(elf_regs)); |
| iovec.iov_base = regs; |
| iovec.iov_len = sizeof(elf_regs); |
| |
| res = ptrace (PTRACE_GETREGSET, pid, NT_PRSTATUS, &iovec); |
| if (res == 0) { |
| if (has_working_ptrace_getregset == -1) { |
| // First call to PTRACE_GETREGSET succesful => |
| has_working_ptrace_getregset = 1; |
| DEBUG(1, "detected a working PTRACE_GETREGSET\n"); |
| } |
| assert (has_working_ptrace_getregset == 1); |
| return True; |
| } |
| else if (has_working_ptrace_getregset == 1) { |
| // We had a working call, but now it fails. |
| // This is unexpected. |
| ERROR(errno, "PTRACE_GETREGSET %ld\n", res); |
| return False; |
| } else { |
| // Check this is the first call: |
| assert (has_working_ptrace_getregset == -1); |
| if (errno == EIO) { |
| DEBUG(1, "detected a broken PTRACE_GETREGSET with EIO\n"); |
| has_working_ptrace_getregset = 0; |
| // Fall over to the PTRACE_GETREGS or PTRACE_PEEKUSER case. |
| } else { |
| ERROR(errno, "broken PTRACE_GETREGSET unexpected errno %ld\n", res); |
| return False; |
| } |
| } |
| } |
| # endif |
| |
| # ifdef HAVE_PTRACE_GETREGS |
| if (has_working_ptrace_getregs) { |
| // Platforms having GETREGS |
| long res; |
| DEBUG(1, "getregs PTRACE_GETREGS\n"); |
| res = ptrace (PTRACE_GETREGS, pid, NULL, regs); |
| if (res == 0) { |
| if (has_working_ptrace_getregs == -1) { |
| // First call to PTRACE_GETREGS succesful => |
| has_working_ptrace_getregs = 1; |
| DEBUG(1, "detected a working PTRACE_GETREGS\n"); |
| } |
| assert (has_working_ptrace_getregs == 1); |
| return True; |
| } |
| else if (has_working_ptrace_getregs == 1) { |
| // We had a working call, but now it fails. |
| // This is unexpected. |
| ERROR(errno, "PTRACE_GETREGS %ld\n", res); |
| return False; |
| } else { |
| // Check this is the first call: |
| assert (has_working_ptrace_getregs == -1); |
| if (errno == EIO) { |
| DEBUG(1, "detected a broken PTRACE_GETREGS with EIO\n"); |
| has_working_ptrace_getregs = 0; |
| // Fall over to the PTRACE_PEEKUSER case. |
| } else { |
| ERROR(errno, "broken PTRACE_GETREGS unexpected errno %ld\n", res); |
| return False; |
| } |
| } |
| } |
| # endif |
| |
| // We assume PTRACE_PEEKUSER is defined everywhere. |
| { |
| # ifdef PT_ENDREGS |
| long peek_bsz = PT_ENDREGS; |
| assert (peek_bsz <= regs_bsz); |
| # else |
| long peek_bsz = regs_bsz-1; |
| # endif |
| char *pregs = (char *) regs; |
| long offset; |
| errno = 0; |
| DEBUG(1, "getregs PTRACE_PEEKUSER(s) peek_bsz %ld\n", peek_bsz); |
| for (offset = 0; offset < peek_bsz; offset = offset + sizeof(long)) { |
| *(long *)(pregs+offset) = ptrace(PTRACE_PEEKUSER, pid, offset, NULL); |
| if (errno != 0) { |
| ERROR(errno, "PTRACE_PEEKUSER offset %ld\n", offset); |
| return False; |
| } |
| } |
| return True; |
| } |
| |
| // If neither of PTRACE_GETREGSET PTRACE_GETREGS PTRACE_PEEKUSER have |
| // returned, then we are in serious trouble. |
| assert (0); |
| } |
| |
| /* Set the registers of pid to regs. |
| regs_bsz value gives the length of *regs. |
| Returns True if all ok, otherwise False. */ |
| static |
| Bool setregs (pid_t pid, void *regs, long regs_bsz) |
| { |
| DEBUG(1, "setregs regs_bsz %ld\n", regs_bsz); |
| |
| // Note : the below is checking for GETREGSET, not SETREGSET |
| // as if one is defined and working, the other one should also work. |
| # ifdef HAVE_PTRACE_GETREGSET |
| if (has_working_ptrace_getregset) { |
| // Platforms having SETREGSET |
| long res; |
| elf_gregset_t elf_regs; |
| struct iovec iovec; |
| |
| // setregset can never be called before getregset has done a runtime check. |
| assert (has_working_ptrace_getregset == 1); |
| DEBUG(1, "setregs PTRACE_SETREGSET sizeof(elf_regs) %zu\n", |
| sizeof(elf_regs)); |
| iovec.iov_base = regs; |
| iovec.iov_len = sizeof(elf_regs); |
| res = ptrace (PTRACE_SETREGSET, pid, NT_PRSTATUS, &iovec); |
| if (res != 0) { |
| ERROR(errno, "PTRACE_SETREGSET %ld\n", res); |
| return False; |
| } |
| return True; |
| } |
| # endif |
| |
| // Note : the below is checking for GETREGS, not SETREGS |
| // as if one is defined and working, the other one should also work. |
| # ifdef HAVE_PTRACE_GETREGS |
| if (has_working_ptrace_getregs) { |
| // Platforms having SETREGS |
| long res; |
| // setregs can never be called before getregs has done a runtime check. |
| assert (has_working_ptrace_getregs == 1); |
| DEBUG(1, "setregs PTRACE_SETREGS\n"); |
| res = ptrace (PTRACE_SETREGS, pid, NULL, regs); |
| if (res != 0) { |
| ERROR(errno, "PTRACE_SETREGS %ld\n", res); |
| return False; |
| } |
| return True; |
| } |
| # endif |
| |
| { |
| char *pregs = (char *) regs; |
| long offset; |
| long res; |
| # ifdef PT_ENDREGS |
| long peek_bsz = PT_ENDREGS; |
| assert (peek_bsz <= regs_bsz); |
| # else |
| long peek_bsz = regs_bsz-1; |
| # endif |
| errno = 0; |
| DEBUG(1, "setregs PTRACE_POKEUSER(s) %ld\n", peek_bsz); |
| for (offset = 0; offset < peek_bsz; offset = offset + sizeof(long)) { |
| res = ptrace(PTRACE_POKEUSER, pid, offset, *(long*)(pregs+offset)); |
| if (errno != 0) { |
| ERROR(errno, "PTRACE_POKEUSER offset %ld res %ld\n", offset, res); |
| return False; |
| } |
| } |
| return True; |
| } |
| |
| // If neither PTRACE_SETREGS not PTRACE_POKEUSER have returned, |
| // then we are in serious trouble. |
| assert (0); |
| } |
| |
| /* Restore the registers to the saved value, then detaches from all threads */ |
| static |
| void restore_and_detach (pid_t pid) |
| { |
| int res; |
| |
| DEBUG(1, "restore_and_detach pid %d pid_of_save_regs %d\n", |
| pid, pid_of_save_regs); |
| |
| if (pid_of_save_regs) { |
| /* In case the 'main pid' has been continued, we need to stop it |
| before resetting the registers. */ |
| if (pid_of_save_regs_continued) { |
| pid_of_save_regs_continued = False; |
| if (!stop(pid_of_save_regs, "sigstop before reset regs")) |
| DEBUG(0, "Could not sigstop before reset"); |
| } |
| |
| DEBUG(1, "setregs restore registers pid %d\n", pid_of_save_regs); |
| if (!setregs(pid_of_save_regs, &user_save.regs, sizeof(user_save.regs))) { |
| ERROR(errno, "setregs restore registers pid %d after cont\n", |
| pid_of_save_regs); |
| } |
| |
| /* Now, we transmit all the signals we have queued. */ |
| if (signal_queue_sz > 0) { |
| int i; |
| for (i = 0; i < signal_queue_sz; i++) { |
| DEBUG(1, "PTRACE_CONT to transmit queued signal %d\n", |
| signal_queue[i].si_signo); |
| res = ptrace (PTRACE_CONT, pid_of_save_regs, NULL, |
| signal_queue[i].si_signo); |
| if (res != 0) |
| ERROR(errno, "PTRACE_CONT with signal %d\n", |
| signal_queue[i].si_signo); |
| if (!stop(pid_of_save_regs, "sigstop after transmit sig")) |
| DEBUG(0, "Could not sigstop after transmit sig"); |
| } |
| free (signal_queue); |
| signal_queue = NULL; |
| signal_queue_sz = 0; |
| } |
| pid_of_save_regs = 0; |
| } else { |
| DEBUG(1, "PTRACE_SETREGS restore registers: no pid\n"); |
| } |
| if (signal_queue) |
| ERROR (0, "One or more signals queued were not delivered. " |
| "First signal: %d\n", signal_queue[0].si_signo); |
| detach_from_all_threads(pid); |
| } |
| |
| Bool invoker_invoke_gdbserver (pid_t pid) |
| { |
| long res; |
| Bool stopped; |
| # if defined(VGA_arm64) |
| /* arm64 is extra special, old glibc defined kernel user_pt_regs, but |
| newer glibc instead define user_regs_struct. */ |
| # ifdef HAVE_SYS_USER_REGS |
| struct user_regs_struct user_mod; |
| # else |
| struct user_pt_regs user_mod; |
| # endif |
| # else |
| struct user user_mod; |
| # endif |
| Addr sp; |
| /* A specific int value is passed to invoke_gdbserver, to check |
| everything goes according to the plan. */ |
| const int check = 0x8BADF00D; // ate bad food. |
| |
| const Addr bad_return = 0; |
| // A bad return address will be pushed on the stack. |
| // The function invoke_gdbserver cannot return. If ever it returns, a NULL |
| // address pushed on the stack should ensure this is detected. |
| |
| /* Not yet attached. If problem, vgdb can abort, |
| no cleanup needed. */ |
| |
| DEBUG(1, "attach to 'main' pid %d\n", pid); |
| if (!attach(pid, "attach main pid")) { |
| ERROR(0, "error attach main pid %d\n", pid); |
| return False; |
| } |
| |
| /* Now, we are attached. If problem, detach and return. */ |
| |
| if (!acquire_and_suspend_threads(pid)) { |
| detach_from_all_threads(pid); |
| /* if the pid does not exist anymore, we better stop */ |
| if (kill(pid, 0) != 0) |
| XERROR (errno, "invoke_gdbserver: check for pid %d existence failed\n", |
| pid); |
| return False; |
| } |
| |
| if (!getregs(pid, &user_mod.regs, sizeof(user_mod.regs))) { |
| detach_from_all_threads(pid); |
| return False; |
| } |
| user_save = user_mod; |
| |
| #if defined(VGA_x86) |
| sp = user_mod.regs.esp; |
| #elif defined(VGA_amd64) |
| sp = user_mod.regs.rsp; |
| if (shared32 != NULL) { |
| /* 64bit vgdb speaking with a 32bit executable. |
| To have system call restart properly, we need to sign extend rax. |
| For more info: |
| web search '[patch] Fix syscall restarts for amd64->i386 biarch' |
| e.g. http://sourceware.org/ml/gdb-patches/2009-11/msg00592.html */ |
| *(long *)&user_save.regs.rax = *(int*)&user_save.regs.rax; |
| DEBUG(1, "Sign extending %8.8lx to %8.8lx\n", |
| user_mod.regs.rax, user_save.regs.rax); |
| } |
| #elif defined(VGA_arm) |
| sp = user_mod.regs.uregs[13]; |
| #elif defined(VGA_arm64) |
| sp = user_mod.sp; |
| #elif defined(VGA_ppc32) |
| sp = user_mod.regs.gpr[1]; |
| #elif defined(VGA_ppc64be) || defined(VGA_ppc64le) |
| sp = user_mod.regs.gpr[1]; |
| #elif defined(VGA_s390x) |
| sp = user_mod.regs.gprs[15]; |
| #elif defined(VGA_mips32) |
| long long *p = (long long *)user_mod.regs; |
| sp = p[29]; |
| #elif defined(VGA_mips64) |
| sp = user_mod.regs[29]; |
| #else |
| I_die_here : (sp) architecture missing in vgdb.c |
| #endif |
| |
| |
| // the magic below is derived from spying what gdb sends to |
| // the (classical) gdbserver when invoking a C function. |
| if (shared32 != NULL) { |
| // vgdb speaking with a 32bit executable. |
| #if defined(VGA_x86) || defined(VGA_amd64) |
| const int regsize = 4; |
| int rw; |
| /* push check arg on the stack */ |
| sp = sp - regsize; |
| DEBUG(1, "push check arg ptrace_write_memory\n"); |
| assert(regsize == sizeof(check)); |
| rw = ptrace_write_memory(pid, sp, |
| &check, |
| regsize); |
| if (rw != 0) { |
| ERROR(rw, "push check arg ptrace_write_memory"); |
| detach_from_all_threads(pid); |
| return False; |
| } |
| |
| sp = sp - regsize; |
| DEBUG(1, "push bad_return return address ptrace_write_memory\n"); |
| // Note that for a 64 bits vgdb, only 4 bytes of NULL bad_return |
| // are written. |
| rw = ptrace_write_memory(pid, sp, |
| &bad_return, |
| regsize); |
| if (rw != 0) { |
| ERROR(rw, "push bad_return return address ptrace_write_memory"); |
| detach_from_all_threads(pid); |
| return False; |
| } |
| #if defined(VGA_x86) |
| /* set ebp, esp, eip and orig_eax to invoke gdbserver */ |
| // compiled in 32bits, speaking with a 32bits exe |
| user_mod.regs.ebp = sp; // bp set to sp |
| user_mod.regs.esp = sp; |
| user_mod.regs.eip = shared32->invoke_gdbserver; |
| user_mod.regs.orig_eax = -1L; |
| #elif defined(VGA_amd64) |
| /* set ebp, esp, eip and orig_eax to invoke gdbserver */ |
| // compiled in 64bits, speaking with a 32bits exe |
| user_mod.regs.rbp = sp; // bp set to sp |
| user_mod.regs.rsp = sp; |
| user_mod.regs.rip = shared32->invoke_gdbserver; |
| user_mod.regs.orig_rax = -1L; |
| #else |
| I_die_here : not x86 or amd64 in x86/amd64 section/ |
| #endif |
| |
| #elif defined(VGA_ppc32) || defined(VGA_ppc64be) || defined(VGA_ppc64le) |
| user_mod.regs.nip = shared32->invoke_gdbserver; |
| user_mod.regs.trap = -1L; |
| /* put check arg in register 3 */ |
| user_mod.regs.gpr[3] = check; |
| /* put NULL return address in Link Register */ |
| user_mod.regs.link = bad_return; |
| |
| #elif defined(VGA_arm) |
| /* put check arg in register 0 */ |
| user_mod.regs.uregs[0] = check; |
| /* put NULL return address in Link Register */ |
| user_mod.regs.uregs[14] = bad_return; |
| user_mod.regs.uregs[15] = shared32->invoke_gdbserver; |
| |
| #elif defined(VGA_arm64) |
| XERROR(0, "TBD arm64: vgdb a 32 bits executable with a 64 bits exe"); |
| |
| #elif defined(VGA_s390x) |
| XERROR(0, "(fn32) s390x has no 32bits implementation"); |
| #elif defined(VGA_mips32) |
| /* put check arg in register 4 */ |
| p[4] = check; |
| /* put NULL return address in ra */ |
| p[31] = bad_return; |
| p[34] = shared32->invoke_gdbserver; |
| p[25] = shared32->invoke_gdbserver; |
| /* make stack space for args */ |
| p[29] = sp - 32; |
| |
| #elif defined(VGA_mips64) |
| assert(0); // cannot vgdb a 32 bits executable with a 64 bits exe |
| #else |
| I_die_here : architecture missing in vgdb.c |
| #endif |
| } |
| |
| else if (shared64 != NULL) { |
| #if defined(VGA_x86) |
| assert(0); // cannot vgdb a 64 bits executable with a 32 bits exe |
| #elif defined(VGA_amd64) |
| // vgdb speaking with a 64 bit executable. |
| const int regsize = 8; |
| int rw; |
| |
| /* give check arg in rdi */ |
| user_mod.regs.rdi = check; |
| |
| /* push return address on stack : return to breakaddr */ |
| sp = sp - regsize; |
| DEBUG(1, "push bad_return return address ptrace_write_memory\n"); |
| rw = ptrace_write_memory(pid, sp, |
| &bad_return, |
| sizeof(bad_return)); |
| if (rw != 0) { |
| ERROR(rw, "push bad_return return address ptrace_write_memory"); |
| detach_from_all_threads(pid); |
| return False; |
| } |
| |
| /* set rbp, rsp, rip and orig_rax to invoke gdbserver */ |
| user_mod.regs.rbp = sp; // bp set to sp |
| user_mod.regs.rsp = sp; |
| user_mod.regs.rip = shared64->invoke_gdbserver; |
| user_mod.regs.orig_rax = -1L; |
| |
| #elif defined(VGA_arm) |
| assert(0); // cannot vgdb a 64 bits executable with a 32 bits exe |
| #elif defined(VGA_arm64) |
| user_mod.regs[0] = check; |
| user_mod.sp = sp; |
| user_mod.pc = shared64->invoke_gdbserver; |
| /* put NULL return address in Link Register */ |
| user_mod.regs[30] = bad_return; |
| |
| #elif defined(VGA_ppc32) |
| assert(0); // cannot vgdb a 64 bits executable with a 32 bits exe |
| #elif defined(VGA_ppc64be) |
| Addr64 func_addr; |
| Addr64 toc_addr; |
| int rw; |
| rw = ptrace_read_memory(pid, shared64->invoke_gdbserver, |
| &func_addr, |
| sizeof(Addr64)); |
| if (rw != 0) { |
| ERROR(rw, "ppc64 read func_addr\n"); |
| detach_from_all_threads(pid); |
| return False; |
| } |
| rw = ptrace_read_memory(pid, shared64->invoke_gdbserver+8, |
| &toc_addr, |
| sizeof(Addr64)); |
| if (rw != 0) { |
| ERROR(rw, "ppc64 read toc_addr\n"); |
| detach_from_all_threads(pid); |
| return False; |
| } |
| // We are not pushing anything on the stack, so it is not |
| // very clear why the sp has to be decreased, but it seems |
| // needed. The ppc64 ABI might give some lights on this ? |
| user_mod.regs.gpr[1] = sp - 220; |
| user_mod.regs.gpr[2] = toc_addr; |
| user_mod.regs.nip = func_addr; |
| user_mod.regs.trap = -1L; |
| /* put check arg in register 3 */ |
| user_mod.regs.gpr[3] = check; |
| /* put bad_return return address in Link Register */ |
| user_mod.regs.link = bad_return; |
| #elif defined(VGA_ppc64le) |
| /* LE does not use the function pointer structure used in BE */ |
| user_mod.regs.nip = shared64->invoke_gdbserver; |
| user_mod.regs.gpr[1] = sp - 512; |
| user_mod.regs.gpr[12] = user_mod.regs.nip; |
| user_mod.regs.trap = -1L; |
| /* put check arg in register 3 */ |
| user_mod.regs.gpr[3] = check; |
| /* put bad_return return address in Link Register */ |
| user_mod.regs.link = bad_return; |
| #elif defined(VGA_s390x) |
| /* put check arg in register r2 */ |
| user_mod.regs.gprs[2] = check; |
| /* bad_return Return address is in r14 */ |
| user_mod.regs.gprs[14] = bad_return; |
| /* minimum stack frame */ |
| sp = sp - 160; |
| user_mod.regs.gprs[15] = sp; |
| /* set program counter */ |
| user_mod.regs.psw.addr = shared64->invoke_gdbserver; |
| #elif defined(VGA_mips32) |
| assert(0); // cannot vgdb a 64 bits executable with a 32 bits exe |
| #elif defined(VGA_mips64) |
| /* put check arg in register 4 */ |
| user_mod.regs[4] = check; |
| /* put NULL return address in ra */ |
| user_mod.regs[31] = bad_return; |
| user_mod.regs[34] = shared64->invoke_gdbserver; |
| user_mod.regs[25] = shared64->invoke_gdbserver; |
| #else |
| I_die_here: architecture missing in vgdb.c |
| #endif |
| } |
| else { |
| assert(0); |
| } |
| |
| if (!setregs(pid, &user_mod.regs, sizeof(user_mod.regs))) { |
| detach_from_all_threads(pid); |
| return False; |
| } |
| /* Now that we have modified the registers, we set |
| pid_of_save_regs to indicate that restore_and_detach |
| must restore the registers in case of cleanup. */ |
| pid_of_save_regs = pid; |
| pid_of_save_regs_continued = False; |
| |
| |
| /* We PTRACE_CONT-inue pid. |
| Either gdbserver will be invoked directly (if all |
| threads are interruptible) or gdbserver will be |
| called soon by the scheduler. In the first case, |
| pid will stop on the break inserted above when |
| gdbserver returns. In the 2nd case, the break will |
| be encountered directly. */ |
| DEBUG(1, "PTRACE_CONT to invoke\n"); |
| res = ptrace (PTRACE_CONT, pid, NULL, NULL); |
| if (res != 0) { |
| ERROR(errno, "PTRACE_CONT\n"); |
| restore_and_detach(pid); |
| return False; |
| } |
| pid_of_save_regs_continued = True; |
| /* Wait for SIGSTOP generated by m_gdbserver.c give_control_back_to_vgdb */ |
| stopped = waitstopped (pid, SIGSTOP, |
| "waitpid status after PTRACE_CONT to invoke"); |
| if (stopped) { |
| /* Here pid has properly stopped on the break. */ |
| pid_of_save_regs_continued = False; |
| restore_and_detach(pid); |
| return True; |
| } else { |
| /* Whatever kind of problem happened. We shutdown. */ |
| shutting_down = True; |
| return False; |
| } |
| } |
| |
| void invoker_cleanup_restore_and_detach(void *v_pid) |
| { |
| DEBUG(1, "invoker_cleanup_restore_and_detach dying: %d\n", dying); |
| if (!dying) |
| restore_and_detach(*(int*)v_pid); |
| } |
| |
| void invoker_restrictions_msg(void) |
| { |
| } |
| |
| void invoker_valgrind_dying(void) |
| { |
| /* Avoid messing up with registers of valgrind when it is dying. */ |
| pid_of_save_regs_continued = False; |
| dying = True; |
| } |
