hotspot/agent/src/os/bsd/ps_proc.c
changeset 10565 dc90c239f4ec
child 15734 68f78eb98356
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/agent/src/os/bsd/ps_proc.c	Sun Sep 25 16:03:29 2011 -0700
@@ -0,0 +1,444 @@
+/*
+ * Copyright (c) 2003, 2010, 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;
+}
+
+// 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 {
+    int ret;
+    int status;
+    do {
+      // Wait for debuggee to stop.
+      ret = waitpid(pid, &status, 0);
+      if (ret >= 0) {
+        if (WIFSTOPPED(status)) {
+          // Debuggee stopped.
+          return true;
+        } 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);
+  }
+}
+
+// -------------------------------------------------------
+// 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;
+  thread_info* thr = 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;
+}