Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.

  *

  * This code 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

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

  * questions.

  *

  */

 #include <limits.h>

 #include <stdio.h>

 #include <stdlib.h>

 #include <string.h>

 #include <errno.h>

 #include <sys/types.h>

 #include <sys/wait.h>

 #include <sys/ptrace.h>

 #include <sys/param.h>

 #include <sys/user.h>

 #include <elf.h>

 #include <sys/elf_common.h>

 #include <sys/link_elf.h>

 #include <libutil.h>

 #include "libproc_impl.h"

 #include "elfmacros.h"

 // This file has the libproc implementation specific to live process

 // For core files, refer to ps_core.c

 static inline uintptr_t align(uintptr_t ptr, size_t size) {

   return (ptr & ~(size - 1));

 }

 // ---------------------------------------------

 // ptrace functions

 // ---------------------------------------------

 // read "size" bytes of data from "addr" within the target process.

 // unlike the standard ptrace() function, process_read_data() can handle

 // unaligned address - alignment check, if required, should be done

 // before calling process_read_data.

 static bool process_read_data(struct ps_prochandle* ph, uintptr_t addr, char *buf, size_t size) {

   int rslt;

   size_t i, words;

   uintptr_t end_addr = addr + size;

   uintptr_t aligned_addr = align(addr, sizeof(int));

   if (aligned_addr != addr) {

     char *ptr = (char *)&rslt;

     errno = 0;

     rslt = ptrace(PT_READ_D, ph->pid, (caddr_t) aligned_addr, 0);

     if (errno) {

       print_debug("ptrace(PT_READ_D, ..) failed for %d bytes @ %lx\n", size, addr);

       return false;

     }

     for (; aligned_addr != addr; aligned_addr++, ptr++);

     for (; ((intptr_t)aligned_addr % sizeof(int)) && aligned_addr < end_addr;

         aligned_addr++)

        *(buf++) = *(ptr++);

   }

   words = (end_addr - aligned_addr) / sizeof(int);

   // assert((intptr_t)aligned_addr % sizeof(int) == 0);

   for (i = 0; i < words; i++) {

     errno = 0;

     rslt = ptrace(PT_READ_D, ph->pid, (caddr_t) aligned_addr, 0);

     if (errno) {

       print_debug("ptrace(PT_READ_D, ..) failed for %d bytes @ %lx\n", size, addr);

       return false;

     }

     *(int *)buf = rslt;

     buf += sizeof(int);

     aligned_addr += sizeof(int);

   }

   if (aligned_addr != end_addr) {

     char *ptr = (char *)&rslt;

     errno = 0;

     rslt = ptrace(PT_READ_D, ph->pid, (caddr_t) aligned_addr, 0);

     if (errno) {

       print_debug("ptrace(PT_READ_D, ..) failed for %d bytes @ %lx\n", size, addr);

       return false;

     }

     for (; aligned_addr != end_addr; aligned_addr++)

        *(buf++) = *(ptr++);

   }

   return true;

 }

 // null implementation for write

 static bool process_write_data(struct ps_prochandle* ph,

                              uintptr_t addr, const char *buf , size_t size) {

   return false;

 }

 // "user" should be a pointer to a reg

 static bool process_get_lwp_regs(struct ps_prochandle* ph, pid_t pid, struct reg *user) {

   // we have already attached to all thread 'pid's, just use ptrace call

   // to get regset now. Note that we don't cache regset upfront for processes.

  if (ptrace(PT_GETREGS, pid, (caddr_t) user, 0) < 0) {

    print_debug("ptrace(PTRACE_GETREGS, ...) failed for lwp %d\n", pid);

    return false;

  }

  return true;

 }

 // fill in ptrace_lwpinfo for lid

 static bool process_get_lwp_info(struct ps_prochandle *ph, lwpid_t lwp_id, void *linfo) {

   errno = 0;

   ptrace(PT_LWPINFO, lwp_id, linfo, sizeof(struct ptrace_lwpinfo));

   return (errno == 0)? true: false;

 }

 static bool ptrace_continue(pid_t pid, int signal) {

   // pass the signal to the process so we don't swallow it

   if (ptrace(PT_CONTINUE, pid, NULL, signal) < 0) {

     print_debug("ptrace(PTRACE_CONT, ..) failed for %d\n", pid);

     return false;

   }

   return true;

 }

 // waits until the ATTACH has stopped the process

 // by signal SIGSTOP

 static bool ptrace_waitpid(pid_t pid) {

   int ret;

   int status;

   do {

     // Wait for debuggee to stop.

     ret = waitpid(pid, &status, 0);

     if (ret >= 0) {

       if (WIFSTOPPED(status)) {

         // Any signal will stop the thread, make sure it is SIGSTOP. Otherwise SIGSTOP

         // will still be pending and delivered when the process is DETACHED and the process

         // will go to sleep.

         if (WSTOPSIG(status) == SIGSTOP) {

           // Debuggee stopped by SIGSTOP.

           return true;

         }

         if (!ptrace_continue(pid, WSTOPSIG(status))) {

           print_error("Failed to correctly attach to VM. VM might HANG! [PTRACE_CONT failed, stopped by %d]\n", WSTOPSIG(status));

           return false;

         }

       } else {

         print_debug("waitpid(): Child process exited/terminated (status = 0x%x)\n", status);

         return false;

       }

     } else {

       switch (errno) {

         case EINTR:

           continue;

           break;

         case ECHILD:

           print_debug("waitpid() failed. Child process pid (%d) does not exist \n", pid);

           break;

         case EINVAL:

           print_debug("waitpid() failed. Invalid options argument.\n");

           break;

         default:

           print_debug("waitpid() failed. Unexpected error %d\n",errno);

       }

       return false;

     }

   } while(true);

 }

 // attach to a process/thread specified by "pid"

 static bool ptrace_attach(pid_t pid) {

   if (ptrace(PT_ATTACH, pid, NULL, 0) < 0) {

     print_debug("ptrace(PTRACE_ATTACH, ..) failed for %d\n", pid);

     return false;

   } else {

     return ptrace_waitpid(pid);

   }

 }

 // -------------------------------------------------------

 // functions for obtaining library information

 // -------------------------------------------------------

 // callback for read_thread_info

 static bool add_new_thread(struct ps_prochandle* ph, pthread_t pthread_id, lwpid_t lwp_id) {

   return add_thread_info(ph, pthread_id, lwp_id) != NULL;

 }

 #if defined(__FreeBSD__) && __FreeBSD_version < 701000

 /*

  * TEXT_START_ADDR from binutils/ld/emulparams/<arch_spec>.sh

  * Not the most robust but good enough.

  */

 #if defined(amd64) || defined(x86_64)

 #define TEXT_START_ADDR 0x400000

 #elif defined(i386)

 #define TEXT_START_ADDR 0x8048000

 #else

 #error TEXT_START_ADDR not defined

 #endif

 #define BUF_SIZE (PATH_MAX + NAME_MAX + 1)

 uintptr_t linkmap_addr(struct ps_prochandle *ph) {

   uintptr_t ehdr_addr, phdr_addr, dyn_addr, dmap_addr, lmap_addr;

   ELF_EHDR ehdr;

   ELF_PHDR *phdrs, *phdr;

   ELF_DYN *dyns, *dyn;

   struct r_debug dmap;

   unsigned long hdrs_size;

   unsigned int i;

   /* read ELF_EHDR at TEXT_START_ADDR and validate */

   ehdr_addr = (uintptr_t)TEXT_START_ADDR;

   if (process_read_data(ph, ehdr_addr, (char *)&ehdr, sizeof(ehdr)) != true) {

     print_debug("process_read_data failed for ehdr_addr %p\n", ehdr_addr);

     return (0);

   }

   if (!IS_ELF(ehdr) ||

         ehdr.e_ident[EI_CLASS] != ELF_TARG_CLASS ||

         ehdr.e_ident[EI_DATA] != ELF_TARG_DATA ||

         ehdr.e_ident[EI_VERSION] != EV_CURRENT ||

         ehdr.e_phentsize != sizeof(ELF_PHDR) ||

         ehdr.e_version != ELF_TARG_VER ||

         ehdr.e_machine != ELF_TARG_MACH) {

     print_debug("not an ELF_EHDR at %p\n", ehdr_addr);

     return (0);

   }

   /* allocate space for all ELF_PHDR's and read */

   phdr_addr = ehdr_addr + ehdr.e_phoff;

   hdrs_size = ehdr.e_phnum * sizeof(ELF_PHDR);

   if ((phdrs = malloc(hdrs_size)) == NULL)

     return (0);

   if (process_read_data(ph, phdr_addr, (char *)phdrs, hdrs_size) != true) {

     print_debug("process_read_data failed for phdr_addr %p\n", phdr_addr);

     return (0);

   }

   /* find PT_DYNAMIC section */

   for (i = 0, phdr = phdrs; i < ehdr.e_phnum; i++, phdr++) {

     if (phdr->p_type == PT_DYNAMIC)

       break;

   }

   if (i >= ehdr.e_phnum) {

     print_debug("PT_DYNAMIC section not found!\n");

     free(phdrs);

     return (0);

   }

   /* allocate space and read in ELF_DYN headers */

   dyn_addr = phdr->p_vaddr;

   hdrs_size = phdr->p_memsz;

   free(phdrs);

   if ((dyns = malloc(hdrs_size)) == NULL)

     return (0);

   if (process_read_data(ph, dyn_addr, (char *)dyns, hdrs_size) != true) {

     print_debug("process_read_data failed for dyn_addr %p\n", dyn_addr);

     free(dyns);

     return (0);

   }

   /* find DT_DEBUG */

   dyn = dyns;

   while (dyn->d_tag != DT_DEBUG && dyn->d_tag != DT_NULL) {

     dyn++;

   }

   if (dyn->d_tag != DT_DEBUG) {

     print_debug("failed to find DT_DEBUG\n");

     free(dyns);

     return (0);

   }

   /* read struct r_debug into dmap */

   dmap_addr = (uintptr_t)dyn->d_un.d_ptr;

   free(dyns);

   if (process_read_data(ph, dmap_addr, (char *)&dmap, sizeof(dmap)) != true) {

     print_debug("process_read_data failed for dmap_addr %p\n", dmap_addr);

     return (0);

   }

   lmap_addr = (uintptr_t)dmap.r_map;

   return (lmap_addr);

 }

 #endif // __FreeBSD__ && __FreeBSD_version < 701000

 static bool read_lib_info(struct ps_prochandle* ph) {

 #if defined(__FreeBSD__) && __FreeBSD_version >= 701000

   struct kinfo_vmentry *freep, *kve;

   int i, cnt;

   freep = kinfo_getvmmap(ph->pid, &cnt);

   if (freep == NULL) {

       print_debug("can't get vm map for pid\n", ph->pid);

       return false;

   }

   for (i = 0; i < cnt; i++) {

     kve = &freep[i];

     if ((kve->kve_flags & KVME_FLAG_COW) &&

         kve->kve_path != NULL &&

         strlen(kve->kve_path) > 0) {

       if (find_lib(ph, kve->kve_path) == false) {

         lib_info* lib;

         if ((lib = add_lib_info(ph, kve->kve_path,

                                 (uintptr_t) kve->kve_start)) == NULL)

           continue; // ignore, add_lib_info prints error

         // we don't need to keep the library open, symtab is already

         // built. Only for core dump we need to keep the fd open.

         close(lib->fd);

         lib->fd = -1;

       }

     }

   }

   free(freep);

   return true;

 #else

   char *l_name;

   struct link_map *lmap;

   uintptr_t lmap_addr;

   if ((l_name = malloc(BUF_SIZE)) == NULL)

     return false;

   if ((lmap = malloc(sizeof(*lmap))) == NULL) {

     free(l_name);

     return false;

   }

   lmap_addr = linkmap_addr(ph);

   if (lmap_addr == 0) {

     free(l_name);

     free(lmap);

     return false;

   }

   do {

     if (process_read_data(ph, lmap_addr, (char *)lmap, sizeof(*lmap)) != true) {

       print_debug("process_read_data failed for lmap_addr %p\n", lmap_addr);

       free (l_name);

       free (lmap);

       return false;

     }

     if (process_read_data(ph, (uintptr_t)lmap->l_name, l_name,

         BUF_SIZE) != true) {

       print_debug("process_read_data failed for lmap->l_name %p\n",

           lmap->l_name);

       free (l_name);

       free (lmap);

       return false;

     }

     if (find_lib(ph, l_name) == false) {

       lib_info* lib;

       if ((lib = add_lib_info(ph, l_name,

                               (uintptr_t) lmap->l_addr)) == NULL)

         continue; // ignore, add_lib_info prints error

       // we don't need to keep the library open, symtab is already

       // built. Only for core dump we need to keep the fd open.

       close(lib->fd);

       lib->fd = -1;

     }

     lmap_addr = (uintptr_t)lmap->l_next;

   } while (lmap->l_next != NULL);

   free (l_name);

   free (lmap);

   return true;

 #endif

 }

 // detach a given pid

 static bool ptrace_detach(pid_t pid) {

   if (pid && ptrace(PT_DETACH, pid, (caddr_t)1, 0) < 0) {

     print_debug("ptrace(PTRACE_DETACH, ..) failed for %d\n", pid);

     return false;

   } else {

     return true;

   }

 }

 static void process_cleanup(struct ps_prochandle* ph) {

   ptrace_detach(ph->pid);

 }

 static ps_prochandle_ops process_ops = {

   .release=  process_cleanup,

   .p_pread=  process_read_data,

   .p_pwrite= process_write_data,

   .get_lwp_regs= process_get_lwp_regs,

   .get_lwp_info= process_get_lwp_info

 };

 // attach to the process. One and only one exposed stuff

 struct ps_prochandle* Pgrab(pid_t pid) {

   struct ps_prochandle* ph = NULL;

   if ( (ph = (struct ps_prochandle*) calloc(1, sizeof(struct ps_prochandle))) == NULL) {

      print_debug("can't allocate memory for ps_prochandle\n");

      return NULL;

   }

   if (ptrace_attach(pid) != true) {

      free(ph);

      return NULL;

   }

   // initialize ps_prochandle

   ph->pid = pid;

   // initialize vtable

   ph->ops = &process_ops;

   // read library info and symbol tables, must do this before attaching threads,

   // as the symbols in the pthread library will be used to figure out

   // the list of threads within the same process.

   if (read_lib_info(ph) != true) {

      ptrace_detach(pid);

      free(ph);

      return NULL;

   }

   // read thread info

   read_thread_info(ph, add_new_thread);

   return ph;

 }