truffle: agent/src/os/bsd/ps

comparison agent/src/os/bsd/ps_core.c @ 3960:f08d439fab8c

7089790: integrate bsd-port changes Reviewed-by: kvn, twisti, jrose Contributed-by: Kurt Miller <kurt@intricatesoftware.com>, Greg Lewis <glewis@eyesbeyond.com>, Jung-uk Kim <jkim@freebsd.org>, Christos Zoulas <christos@zoulas.com>, Landon Fuller <landonf@plausible.coop>, The FreeBSD Foundation <board@freebsdfoundation.org>, Michael Franz <mvfranz@gmail.com>, Roger Hoover <rhoover@apple.com>, Alexander Strange <astrange@apple.com>

author	never
date	Sun, 25 Sep 2011 16:03:29 -0700
parents
children	da91efe96a93

comparison

equal deleted inserted replaced

-:eda6988c0d81
+:f08d439fab8c
+/*
+* 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 <jni.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <elf.h>
+#include <link.h>
+#include "libproc_impl.h"
+#include "salibelf.h"
+// This file has the libproc implementation to read core files.
+// For live processes, refer to ps_proc.c. Portions of this is adapted
+// /modelled after Solaris libproc.so (in particular Pcore.c)
+//----------------------------------------------------------------------
+// ps_prochandle cleanup helper functions
+// close all file descriptors
+static void close_elf_files(struct ps_prochandle* ph) {
+lib_info* lib = NULL;
+// close core file descriptor
+if (ph->core->core_fd >= 0)
+close(ph->core->core_fd);
+// close exec file descriptor
+if (ph->core->exec_fd >= 0)
+close(ph->core->exec_fd);
+// close interp file descriptor
+if (ph->core->interp_fd >= 0)
+close(ph->core->interp_fd);
+// close class share archive file
+if (ph->core->classes_jsa_fd >= 0)
+close(ph->core->classes_jsa_fd);
+// close all library file descriptors
+lib = ph->libs;
+while (lib) {
+int fd = lib->fd;
+if (fd >= 0 && fd != ph->core->exec_fd) close(fd);
+lib = lib->next;
+}
+}
+// clean all map_info stuff
+static void destroy_map_info(struct ps_prochandle* ph) {
+map_info* map = ph->core->maps;
+while (map) {
+map_info* next = map->next;
+free(map);
+map = next;
+}
+if (ph->core->map_array) {
+free(ph->core->map_array);
+}
+// Part of the class sharing workaround
+map = ph->core->class_share_maps;
+while (map) {
+map_info* next = map->next;
+free(map);
+map = next;
+}
+}
+// ps_prochandle operations
+static void core_release(struct ps_prochandle* ph) {
+if (ph->core) {
+close_elf_files(ph);
+destroy_map_info(ph);
+free(ph->core);
+}
+}
+static map_info* allocate_init_map(int fd, off_t offset, uintptr_t vaddr, size_t memsz) {
+map_info* map;
+if ( (map = (map_info*) calloc(1, sizeof(map_info))) == NULL) {
+print_debug("can't allocate memory for map_info\n");
+return NULL;
+}
+// initialize map
+map->fd     = fd;
+map->offset = offset;
+map->vaddr  = vaddr;
+map->memsz  = memsz;
+return map;
+}
+// add map info with given fd, offset, vaddr and memsz
+static map_info* add_map_info(struct ps_prochandle* ph, int fd, off_t offset,
+uintptr_t vaddr, size_t memsz) {
+map_info* map;
+if ((map = allocate_init_map(fd, offset, vaddr, memsz)) == NULL) {
+return NULL;
+}
+// add this to map list
+map->next  = ph->core->maps;
+ph->core->maps   = map;
+ph->core->num_maps++;
+return map;
+}
+// Part of the class sharing workaround
+static map_info* add_class_share_map_info(struct ps_prochandle* ph, off_t offset,
+uintptr_t vaddr, size_t memsz) {
+map_info* map;
+if ((map = allocate_init_map(ph->core->classes_jsa_fd,
+offset, vaddr, memsz)) == NULL) {
+return NULL;
+}
+map->next = ph->core->class_share_maps;
+ph->core->class_share_maps = map;
+return map;
+}
+// Return the map_info for the given virtual address.  We keep a sorted
+// array of pointers in ph->map_array, so we can binary search.
+static map_info* core_lookup(struct ps_prochandle *ph, uintptr_t addr)
+{
+int mid, lo = 0, hi = ph->core->num_maps - 1;
+map_info *mp;
+while (hi - lo > 1) {
+mid = (lo + hi) / 2;
+if (addr >= ph->core->map_array[mid]->vaddr)
+lo = mid;
+else
+hi = mid;
+}
+if (addr < ph->core->map_array[hi]->vaddr)
+mp = ph->core->map_array[lo];
+else
+mp = ph->core->map_array[hi];
+if (addr >= mp->vaddr && addr < mp->vaddr + mp->memsz)
+return (mp);
+// Part of the class sharing workaround
+// Unfortunately, we have no way of detecting -Xshare state.
+// Check out the share maps atlast, if we don't find anywhere.
+// This is done this way so to avoid reading share pages
+// ahead of other normal maps. For eg. with -Xshare:off we don't
+// want to prefer class sharing data to data from core.
+mp = ph->core->class_share_maps;
+if (mp) {
+print_debug("can't locate map_info at 0x%lx, trying class share maps\n",
+addr);
+}
+while (mp) {
+if (addr >= mp->vaddr && addr < mp->vaddr + mp->memsz) {
+print_debug("located map_info at 0x%lx from class share maps\n",
+addr);
+return (mp);
+}
+mp = mp->next;
+}
+print_debug("can't locate map_info at 0x%lx\n", addr);
+return (NULL);
+}
+//---------------------------------------------------------------
+// Part of the class sharing workaround:
+//
+// With class sharing, pages are mapped from classes[_g].jsa file.
+// The read-only class sharing pages are mapped as MAP_SHARED,
+// PROT_READ pages. These pages are not dumped into core dump.
+// With this workaround, these pages are read from classes[_g].jsa.
+// FIXME: !HACK ALERT!
+// The format of sharing achive file header is needed to read shared heap
+// file mappings. For now, I am hard coding portion of FileMapHeader here.
+// Refer to filemap.hpp.
+// FileMapHeader describes the shared space data in the file to be
+// mapped.  This structure gets written to a file.  It is not a class,
+// so that the compilers don't add any compiler-private data to it.
+// Refer to CompactingPermGenGen::n_regions in compactingPermGenGen.hpp
+#define NUM_SHARED_MAPS 4
+// Refer to FileMapInfo::_current_version in filemap.hpp
+#define CURRENT_ARCHIVE_VERSION 1
+struct FileMapHeader {
+int   _magic;              // identify file type.
+int   _version;            // (from enum, above.)
+size_t _alignment;         // how shared archive should be aligned
+struct space_info {
+int    _file_offset;     // sizeof(this) rounded to vm page size
+char*  _base;            // copy-on-write base address
+size_t _capacity;        // for validity checking
+size_t _used;            // for setting space top on read
+// 4991491 NOTICE These are C++ bool's in filemap.hpp and must match up with
+// the C type matching the C++ bool type on any given platform. For
+// Hotspot on BSD we assume the corresponding C type is char but
+// licensees on BSD versions may need to adjust the type of these fields.
+char   _read_only;       // read only space?
+char   _allow_exec;      // executable code in space?
+} _space[NUM_SHARED_MAPS]; // was _space[CompactingPermGenGen::n_regions];
+// Ignore the rest of the FileMapHeader. We don't need those fields here.
+};
+static bool read_jboolean(struct ps_prochandle* ph, uintptr_t addr, jboolean* pvalue) {
+jboolean i;
+if (ps_pread(ph, (psaddr_t) addr, &i, sizeof(i)) == PS_OK) {
+*pvalue = i;
+return true;
+} else {
+return false;
+}
+}
+static bool read_pointer(struct ps_prochandle* ph, uintptr_t addr, uintptr_t* pvalue) {
+uintptr_t uip;
+if (ps_pread(ph, (psaddr_t) addr, &uip, sizeof(uip)) == PS_OK) {
+*pvalue = uip;
+return true;
+} else {
+return false;
+}
+}
+// used to read strings from debuggee
+static bool read_string(struct ps_prochandle* ph, uintptr_t addr, char* buf, size_t size) {
+size_t i = 0;
+char  c = ' ';
+while (c != '\0') {
+if (ps_pread(ph, (psaddr_t) addr, &c, sizeof(char)) != PS_OK)
+return false;
+if (i < size - 1)
+buf[i] = c;
+else // smaller buffer
+return false;
+i++; addr++;
+}
+buf[i] = '\0';
+return true;
+}
+#define USE_SHARED_SPACES_SYM "UseSharedSpaces"
+// mangled name of Arguments::SharedArchivePath
+#define SHARED_ARCHIVE_PATH_SYM "_ZN9Arguments17SharedArchivePathE"
+static bool init_classsharing_workaround(struct ps_prochandle* ph) {
+lib_info* lib = ph->libs;
+while (lib != NULL) {
+// we are iterating over shared objects from the core dump. look for
+// libjvm[_g].so.
+const char *jvm_name = 0;
+if ((jvm_name = strstr(lib->name, "/libjvm.so")) != 0 ||
+(jvm_name = strstr(lib->name, "/libjvm_g.so")) != 0) {
+char classes_jsa[PATH_MAX];
+struct FileMapHeader header;
+size_t n = 0;
+int fd = -1, m = 0;
+uintptr_t base = 0, useSharedSpacesAddr = 0;
+uintptr_t sharedArchivePathAddrAddr = 0, sharedArchivePathAddr = 0;
+jboolean useSharedSpaces = 0;
+memset(classes_jsa, 0, sizeof(classes_jsa));
+jvm_name = lib->name;
+useSharedSpacesAddr = lookup_symbol(ph, jvm_name, USE_SHARED_SPACES_SYM);
+if (useSharedSpacesAddr == 0) {
+print_debug("can't lookup 'UseSharedSpaces' flag\n");
+return false;
+}
+// Hotspot vm types are not exported to build this library. So
+// using equivalent type jboolean to read the value of
+// UseSharedSpaces which is same as hotspot type "bool".
+if (read_jboolean(ph, useSharedSpacesAddr, &useSharedSpaces) != true) {
+print_debug("can't read the value of 'UseSharedSpaces' flag\n");
+return false;
+}
+if ((int)useSharedSpaces == 0) {
+print_debug("UseSharedSpaces is false, assuming -Xshare:off!\n");
+return true;
+}
+sharedArchivePathAddrAddr = lookup_symbol(ph, jvm_name, SHARED_ARCHIVE_PATH_SYM);
+if (sharedArchivePathAddrAddr == 0) {
+print_debug("can't lookup shared archive path symbol\n");
+return false;
+}
+if (read_pointer(ph, sharedArchivePathAddrAddr, &sharedArchivePathAddr) != true) {
+print_debug("can't read shared archive path pointer\n");
+return false;
+}
+if (read_string(ph, sharedArchivePathAddr, classes_jsa, sizeof(classes_jsa)) != true) {
+print_debug("can't read shared archive path value\n");
+return false;
+}
+print_debug("looking for %s\n", classes_jsa);
+// open the class sharing archive file
+fd = pathmap_open(classes_jsa);
+if (fd < 0) {
+print_debug("can't open %s!\n", classes_jsa);
+ph->core->classes_jsa_fd = -1;
+return false;
+} else {
+print_debug("opened %s\n", classes_jsa);
+}
+// read FileMapHeader from the file
+memset(&header, 0, sizeof(struct FileMapHeader));
+if ((n = read(fd, &header, sizeof(struct FileMapHeader)))
+!= sizeof(struct FileMapHeader)) {
+print_debug("can't read shared archive file map header from %s\n", classes_jsa);
+close(fd);
+return false;
+}
+// check file magic
+if (header._magic != 0xf00baba2) {
+print_debug("%s has bad shared archive file magic number 0x%x, expecing 0xf00baba2\n",
+classes_jsa, header._magic);
+close(fd);
+return false;
+}
+// check version
+if (header._version != CURRENT_ARCHIVE_VERSION) {
+print_debug("%s has wrong shared archive file version %d, expecting %d\n",
+classes_jsa, header._version, CURRENT_ARCHIVE_VERSION);
+close(fd);
+return false;
+}
+ph->core->classes_jsa_fd = fd;
+// add read-only maps from classes[_g].jsa to the list of maps
+for (m = 0; m < NUM_SHARED_MAPS; m++) {
+if (header._space[m]._read_only) {
+base = (uintptr_t) header._space[m]._base;
+// no need to worry about the fractional pages at-the-end.
+// possible fractional pages are handled by core_read_data.
+add_class_share_map_info(ph, (off_t) header._space[m]._file_offset,
+base, (size_t) header._space[m]._used);
+print_debug("added a share archive map at 0x%lx\n", base);
+}
+}
+return true;
+}
+lib = lib->next;
+}
+return true;
+}
+//---------------------------------------------------------------------------
+// functions to handle map_info
+// Order mappings based on virtual address.  We use this function as the
+// callback for sorting the array of map_info pointers.
+static int core_cmp_mapping(const void *lhsp, const void *rhsp)
+{
+const map_info *lhs = *((const map_info **)lhsp);
+const map_info *rhs = *((const map_info **)rhsp);
+if (lhs->vaddr == rhs->vaddr)
+return (0);
+return (lhs->vaddr < rhs->vaddr ? -1 : 1);
+}
+// we sort map_info by starting virtual address so that we can do
+// binary search to read from an address.
+static bool sort_map_array(struct ps_prochandle* ph) {
+size_t num_maps = ph->core->num_maps;
+map_info* map = ph->core->maps;
+int i = 0;
+// allocate map_array
+map_info** array;
+if ( (array = (map_info**) malloc(sizeof(map_info*) * num_maps)) == NULL) {
+print_debug("can't allocate memory for map array\n");
+return false;
+}
+// add maps to array
+while (map) {
+array[i] = map;
+i++;
+map = map->next;
+}
+// sort is called twice. If this is second time, clear map array
+if (ph->core->map_array) free(ph->core->map_array);
+ph->core->map_array = array;
+// sort the map_info array by base virtual address.
+qsort(ph->core->map_array, ph->core->num_maps, sizeof (map_info*),
+core_cmp_mapping);
+// print map
+if (is_debug()) {
+int j = 0;
+print_debug("---- sorted virtual address map ----\n");
+for (j = 0; j < ph->core->num_maps; j++) {
+print_debug("base = 0x%lx\tsize = %d\n", ph->core->map_array[j]->vaddr,
+ph->core->map_array[j]->memsz);
+}
+}
+return true;
+}
+#ifndef MIN
+#define MIN(x, y) (((x) < (y))? (x): (y))
+#endif
+static bool core_read_data(struct ps_prochandle* ph, uintptr_t addr, char *buf, size_t size) {
+ssize_t resid = size;
+int page_size=sysconf(_SC_PAGE_SIZE);
+while (resid != 0) {
+map_info *mp = core_lookup(ph, addr);
+uintptr_t mapoff;
+ssize_t len, rem;
+off_t off;
+int fd;
+if (mp == NULL)
+break;  /* No mapping for this address */
+fd = mp->fd;
+mapoff = addr - mp->vaddr;
+len = MIN(resid, mp->memsz - mapoff);
+off = mp->offset + mapoff;
+if ((len = pread(fd, buf, len, off)) <= 0)
+break;
+resid -= len;
+addr += len;
+buf = (char *)buf + len;
+// mappings always start at page boundary. But, may end in fractional
+// page. fill zeros for possible fractional page at the end of a mapping.
+rem = mp->memsz % page_size;
+if (rem > 0) {
+rem = page_size - rem;
+len = MIN(resid, rem);
+resid -= len;
+addr += len;
+// we are not assuming 'buf' to be zero initialized.
+memset(buf, 0, len);
+buf += len;
+}
+}
+if (resid) {
+print_debug("core read failed for %d byte(s) @ 0x%lx (%d more bytes)\n",
+size, addr, resid);
+return false;
+} else {
+return true;
+}
+}
+// null implementation for write
+static bool core_write_data(struct ps_prochandle* ph,
+uintptr_t addr, const char *buf , size_t size) {
+return false;
+}
+static bool core_get_lwp_regs(struct ps_prochandle* ph, lwpid_t lwp_id,
+struct reg* regs) {
+// for core we have cached the lwp regs from NOTE section
+thread_info* thr = ph->threads;
+while (thr) {
+if (thr->lwp_id == lwp_id) {
+memcpy(regs, &thr->regs, sizeof(struct reg));
+return true;
+}
+thr = thr->next;
+}
+return false;
+}
+static bool core_get_lwp_info(struct ps_prochandle *ph, lwpid_t lwp_id, void *linfo) {
+print_debug("core_get_lwp_info not implemented\n");
+return false;
+}
+static ps_prochandle_ops core_ops = {
+.release=  core_release,
+.p_pread=  core_read_data,
+.p_pwrite= core_write_data,
+.get_lwp_regs= core_get_lwp_regs,
+.get_lwp_info= core_get_lwp_info
+};
+// read regs and create thread from NT_PRSTATUS entries from core file
+static bool core_handle_prstatus(struct ps_prochandle* ph, const char* buf, size_t nbytes) {
+// we have to read prstatus_t from buf
+// assert(nbytes == sizeof(prstaus_t), "size mismatch on prstatus_t");
+prstatus_t* prstat = (prstatus_t*) buf;
+thread_info* newthr;
+print_debug("got integer regset for lwp %d\n", prstat->pr_pid);
+// we set pthread_t to -1 for core dump
+if((newthr = add_thread_info(ph, (pthread_t) -1,  prstat->pr_pid)) == NULL)
+return false;
+// copy regs
+memcpy(&newthr->regs, &prstat->pr_reg, sizeof(struct reg));
+if (is_debug()) {
+print_debug("integer regset\n");
+#ifdef i386
+// print the regset
+print_debug("\teax = 0x%x\n", newthr->regs.r_eax);
+print_debug("\tebx = 0x%x\n", newthr->regs.r_ebx);
+print_debug("\tecx = 0x%x\n", newthr->regs.r_ecx);
+print_debug("\tedx = 0x%x\n", newthr->regs.r_edx);
+print_debug("\tesp = 0x%x\n", newthr->regs.r_esp);
+print_debug("\tebp = 0x%x\n", newthr->regs.r_ebp);
+print_debug("\tesi = 0x%x\n", newthr->regs.r_esi);
+print_debug("\tedi = 0x%x\n", newthr->regs.r_edi);
+print_debug("\teip = 0x%x\n", newthr->regs.r_eip);
+#endif
+#if defined(amd64) || defined(x86_64)
+// print the regset
+print_debug("\tr15 = 0x%lx\n", newthr->regs.r_r15);
+print_debug("\tr14 = 0x%lx\n", newthr->regs.r_r14);
+print_debug("\tr13 = 0x%lx\n", newthr->regs.r_r13);
+print_debug("\tr12 = 0x%lx\n", newthr->regs.r_r12);
+print_debug("\trbp = 0x%lx\n", newthr->regs.r_rbp);
+print_debug("\trbx = 0x%lx\n", newthr->regs.r_rbx);
+print_debug("\tr11 = 0x%lx\n", newthr->regs.r_r11);
+print_debug("\tr10 = 0x%lx\n", newthr->regs.r_r10);
+print_debug("\tr9 = 0x%lx\n", newthr->regs.r_r9);
+print_debug("\tr8 = 0x%lx\n", newthr->regs.r_r8);
+print_debug("\trax = 0x%lx\n", newthr->regs.r_rax);
+print_debug("\trcx = 0x%lx\n", newthr->regs.r_rcx);
+print_debug("\trdx = 0x%lx\n", newthr->regs.r_rdx);
+print_debug("\trsi = 0x%lx\n", newthr->regs.r_rsi);
+print_debug("\trdi = 0x%lx\n", newthr->regs.r_rdi);
+//print_debug("\torig_rax = 0x%lx\n", newthr->regs.orig_rax);
+print_debug("\trip = 0x%lx\n", newthr->regs.r_rip);
+print_debug("\tcs = 0x%lx\n", newthr->regs.r_cs);
+//print_debug("\teflags = 0x%lx\n", newthr->regs.eflags);
+print_debug("\trsp = 0x%lx\n", newthr->regs.r_rsp);
+print_debug("\tss = 0x%lx\n", newthr->regs.r_ss);
+//print_debug("\tfs_base = 0x%lx\n", newthr->regs.fs_base);
+//print_debug("\tgs_base = 0x%lx\n", newthr->regs.gs_base);
+//print_debug("\tds = 0x%lx\n", newthr->regs.ds);
+//print_debug("\tes = 0x%lx\n", newthr->regs.es);
+//print_debug("\tfs = 0x%lx\n", newthr->regs.fs);
+//print_debug("\tgs = 0x%lx\n", newthr->regs.gs);
+#endif
+}
+return true;
+}
+#define ROUNDUP(x, y)  ((((x)+((y)-1))/(y))*(y))
+// read NT_PRSTATUS entries from core NOTE segment
+static bool core_handle_note(struct ps_prochandle* ph, ELF_PHDR* note_phdr) {
+char* buf = NULL;
+char* p = NULL;
+size_t size = note_phdr->p_filesz;
+// we are interested in just prstatus entries. we will ignore the rest.
+// Advance the seek pointer to the start of the PT_NOTE data
+if (lseek(ph->core->core_fd, note_phdr->p_offset, SEEK_SET) == (off_t)-1) {
+print_debug("failed to lseek to PT_NOTE data\n");
+return false;
+}
+// Now process the PT_NOTE structures.  Each one is preceded by
+// an Elf{32/64}_Nhdr structure describing its type and size.
+if ( (buf = (char*) malloc(size)) == NULL) {
+print_debug("can't allocate memory for reading core notes\n");
+goto err;
+}
+// read notes into buffer
+if (read(ph->core->core_fd, buf, size) != size) {
+print_debug("failed to read notes, core file must have been truncated\n");
+goto err;
+}
+p = buf;
+while (p < buf + size) {
+ELF_NHDR* notep = (ELF_NHDR*) p;
+char* descdata  = p + sizeof(ELF_NHDR) + ROUNDUP(notep->n_namesz, 4);
+print_debug("Note header with n_type = %d and n_descsz = %u\n",
+notep->n_type, notep->n_descsz);
+if (notep->n_type == NT_PRSTATUS) {
+if (core_handle_prstatus(ph, descdata, notep->n_descsz) != true)
+return false;
+}
+p = descdata + ROUNDUP(notep->n_descsz, 4);
+}
+free(buf);
+return true;
+err:
+if (buf) free(buf);
+return false;
+}
+// read all segments from core file
+static bool read_core_segments(struct ps_prochandle* ph, ELF_EHDR* core_ehdr) {
+int i = 0;
+ELF_PHDR* phbuf = NULL;
+ELF_PHDR* core_php = NULL;
+if ((phbuf =  read_program_header_table(ph->core->core_fd, core_ehdr)) == NULL)
+return false;
+/*
+* Now iterate through the program headers in the core file.
+* We're interested in two types of Phdrs: PT_NOTE (which
+* contains a set of saved /proc structures), and PT_LOAD (which
+* represents a memory mapping from the process's address space).
+*
+* Difference b/w Solaris PT_NOTE and BSD PT_NOTE:
+*
+*     In Solaris there are two PT_NOTE segments the first PT_NOTE (if present)
+*     contains /proc structs in the pre-2.6 unstructured /proc format. the last
+*     PT_NOTE has data in new /proc format.
+*
+*     In Solaris, there is only one pstatus (process status). pstatus contains
+*     integer register set among other stuff. For each LWP, we have one lwpstatus
+*     entry that has integer regset for that LWP.
+*
+*     Linux threads are actually 'clone'd processes. To support core analysis
+*     of "multithreaded" process, Linux creates more than one pstatus (called
+*     "prstatus") entry in PT_NOTE. Each prstatus entry has integer regset for one
+*     "thread". Please refer to Linux kernel src file 'fs/binfmt_elf.c', in particular
+*     function "elf_core_dump".
+*/
+for (core_php = phbuf, i = 0; i < core_ehdr->e_phnum; i++) {
+switch (core_php->p_type) {
+case PT_NOTE:
+if (core_handle_note(ph, core_php) != true) goto err;
+break;
+case PT_LOAD: {
+if (core_php->p_filesz != 0) {
+if (add_map_info(ph, ph->core->core_fd, core_php->p_offset,
+core_php->p_vaddr, core_php->p_filesz) == NULL) goto err;
+}
+break;
+}
+}
+core_php++;
+}
+free(phbuf);
+return true;
+err:
+free(phbuf);
+return false;
+}
+// read segments of a shared object
+static bool read_lib_segments(struct ps_prochandle* ph, int lib_fd, ELF_EHDR* lib_ehdr, uintptr_t lib_base) {
+int i = 0;
+ELF_PHDR* phbuf;
+ELF_PHDR* lib_php = NULL;
+if ((phbuf = read_program_header_table(lib_fd, lib_ehdr)) == NULL)
+return false;
+// we want to process only PT_LOAD segments that are not writable.
+// i.e., text segments. The read/write/exec (data) segments would
+// have been already added from core file segments.
+for (lib_php = phbuf, i = 0; i < lib_ehdr->e_phnum; i++) {
+if ((lib_php->p_type == PT_LOAD) && !(lib_php->p_flags & PF_W) && (lib_php->p_filesz != 0)) {
+if (add_map_info(ph, lib_fd, lib_php->p_offset, lib_php->p_vaddr + lib_base, lib_php->p_filesz) == NULL)
+goto err;
+}
+lib_php++;
+}
+free(phbuf);
+return true;
+err:
+free(phbuf);
+return false;
+}
+// process segments from interpreter (ld-elf.so.1)
+static bool read_interp_segments(struct ps_prochandle* ph) {
+ELF_EHDR interp_ehdr;
+if (read_elf_header(ph->core->interp_fd, &interp_ehdr) != true) {
+print_debug("interpreter is not a valid ELF file\n");
+return false;
+}
+if (read_lib_segments(ph, ph->core->interp_fd, &interp_ehdr, ph->core->ld_base_addr) != true) {
+print_debug("can't read segments of interpreter\n");
+return false;
+}
+return true;
+}
+// process segments of a a.out
+static bool read_exec_segments(struct ps_prochandle* ph, ELF_EHDR* exec_ehdr) {
+int i = 0;
+ELF_PHDR* phbuf = NULL;
+ELF_PHDR* exec_php = NULL;
+if ((phbuf = read_program_header_table(ph->core->exec_fd, exec_ehdr)) == NULL)
+return false;
+for (exec_php = phbuf, i = 0; i < exec_ehdr->e_phnum; i++) {
+switch (exec_php->p_type) {
+// add mappings for PT_LOAD segments
+case PT_LOAD: {
+// add only non-writable segments of non-zero filesz
+if (!(exec_php->p_flags & PF_W) && exec_php->p_filesz != 0) {
+if (add_map_info(ph, ph->core->exec_fd, exec_php->p_offset, exec_php->p_vaddr, exec_php->p_filesz) == NULL) goto err;
+}
+break;
+}
+// read the interpreter and it's segments
+case PT_INTERP: {
+char interp_name[BUF_SIZE];
+pread(ph->core->exec_fd, interp_name, MIN(exec_php->p_filesz, BUF_SIZE), exec_php->p_offset);
+print_debug("ELF interpreter %s\n", interp_name);
+// read interpreter segments as well
+if ((ph->core->interp_fd = pathmap_open(interp_name)) < 0) {
+print_debug("can't open runtime loader\n");
+goto err;
+}
+break;
+}
+// from PT_DYNAMIC we want to read address of first link_map addr
+case PT_DYNAMIC: {
+ph->core->dynamic_addr = exec_php->p_vaddr;
+print_debug("address of _DYNAMIC is 0x%lx\n", ph->core->dynamic_addr);
+break;
+}
+} // switch
+exec_php++;
+} // for
+free(phbuf);
+return true;
+err:
+free(phbuf);
+return false;
+}
+#define FIRST_LINK_MAP_OFFSET offsetof(struct r_debug,  r_map)
+#define LD_BASE_OFFSET        offsetof(struct r_debug,  r_ldbase)
+#define LINK_MAP_ADDR_OFFSET  offsetof(struct link_map, l_addr)
+#define LINK_MAP_NAME_OFFSET  offsetof(struct link_map, l_name)
+#define LINK_MAP_NEXT_OFFSET  offsetof(struct link_map, l_next)
+// read shared library info from runtime linker's data structures.
+// This work is done by librtlb_db in Solaris
+static bool read_shared_lib_info(struct ps_prochandle* ph) {
+uintptr_t addr = ph->core->dynamic_addr;
+uintptr_t debug_base;
+uintptr_t first_link_map_addr;
+uintptr_t ld_base_addr;
+uintptr_t link_map_addr;
+uintptr_t lib_base_diff;
+uintptr_t lib_base;
+uintptr_t lib_name_addr;
+char lib_name[BUF_SIZE];
+ELF_DYN dyn;
+ELF_EHDR elf_ehdr;
+int lib_fd;
+// _DYNAMIC has information of the form
+//         [tag] [data] [tag] [data] .....
+// Both tag and data are pointer sized.
+// We look for dynamic info with DT_DEBUG. This has shared object info.
+// refer to struct r_debug in link.h
+dyn.d_tag = DT_NULL;
+while (dyn.d_tag != DT_DEBUG) {
+if (ps_pread(ph, (psaddr_t) addr, &dyn, sizeof(ELF_DYN)) != PS_OK) {
+print_debug("can't read debug info from _DYNAMIC\n");
+return false;
+}
+addr += sizeof(ELF_DYN);
+}
+// we have got Dyn entry with DT_DEBUG
+debug_base = dyn.d_un.d_ptr;
+// at debug_base we have struct r_debug. This has first link map in r_map field
+if (ps_pread(ph, (psaddr_t) debug_base + FIRST_LINK_MAP_OFFSET,
+&first_link_map_addr, sizeof(uintptr_t)) != PS_OK) {
+print_debug("can't read first link map address\n");
+return false;
+}
+// read ld_base address from struct r_debug
+// XXX: There is no r_ldbase member on BSD
+/*
+if (ps_pread(ph, (psaddr_t) debug_base + LD_BASE_OFFSET, &ld_base_addr,
+sizeof(uintptr_t)) != PS_OK) {
+print_debug("can't read ld base address\n");
+return false;
+}
+ph->core->ld_base_addr = ld_base_addr;
+*/
+ph->core->ld_base_addr = 0;
+print_debug("interpreter base address is 0x%lx\n", ld_base_addr);
+// now read segments from interp (i.e ld-elf.so.1)
+if (read_interp_segments(ph) != true)
+return false;
+// after adding interpreter (ld.so) mappings sort again
+if (sort_map_array(ph) != true)
+return false;
+print_debug("first link map is at 0x%lx\n", first_link_map_addr);
+link_map_addr = first_link_map_addr;
+while (link_map_addr != 0) {
+// read library base address of the .so. Note that even though <sys/link.h> calls
+// link_map->l_addr as "base address",  this is * not * really base virtual
+// address of the shared object. This is actually the difference b/w the virtual
+// address mentioned in shared object and the actual virtual base where runtime
+// linker loaded it. We use "base diff" in read_lib_segments call below.
+if (ps_pread(ph, (psaddr_t) link_map_addr + LINK_MAP_ADDR_OFFSET,
+&lib_base_diff, sizeof(uintptr_t)) != PS_OK) {
+print_debug("can't read shared object base address diff\n");
+return false;
+}
+// read address of the name
+if (ps_pread(ph, (psaddr_t) link_map_addr + LINK_MAP_NAME_OFFSET,
+&lib_name_addr, sizeof(uintptr_t)) != PS_OK) {
+print_debug("can't read address of shared object name\n");
+return false;
+}
+// read name of the shared object
+if (read_string(ph, (uintptr_t) lib_name_addr, lib_name, sizeof(lib_name)) != true) {
+print_debug("can't read shared object name\n");
+return false;
+}
+if (lib_name[0] != '\0') {
+// ignore empty lib names
+lib_fd = pathmap_open(lib_name);
+if (lib_fd < 0) {
+print_debug("can't open shared object %s\n", lib_name);
+// continue with other libraries...
+} else {
+if (read_elf_header(lib_fd, &elf_ehdr)) {
+lib_base = lib_base_diff + find_base_address(lib_fd, &elf_ehdr);
+print_debug("reading library %s @ 0x%lx [ 0x%lx ]\n",
+lib_name, lib_base, lib_base_diff);
+// while adding library mappings we need to use "base difference".
+if (! read_lib_segments(ph, lib_fd, &elf_ehdr, lib_base_diff)) {
+print_debug("can't read shared object's segments\n");
+close(lib_fd);
+return false;
+}
+add_lib_info_fd(ph, lib_name, lib_fd, lib_base);
+// Map info is added for the library (lib_name) so
+// we need to re-sort it before calling the p_pdread.
+if (sort_map_array(ph) != true)
+return false;
+} else {
+print_debug("can't read ELF header for shared object %s\n", lib_name);
+close(lib_fd);
+// continue with other libraries...
+}
+}
+}
+// read next link_map address
+if (ps_pread(ph, (psaddr_t) link_map_addr + LINK_MAP_NEXT_OFFSET,
+&link_map_addr, sizeof(uintptr_t)) != PS_OK) {
+print_debug("can't read next link in link_map\n");
+return false;
+}
+}
+return true;
+}
+// the one and only one exposed stuff from this file
+struct ps_prochandle* Pgrab_core(const char* exec_file, const char* core_file) {
+ELF_EHDR core_ehdr;
+ELF_EHDR exec_ehdr;
+struct ps_prochandle* ph = (struct ps_prochandle*) calloc(1, sizeof(struct ps_prochandle));
+if (ph == NULL) {
+print_debug("can't allocate ps_prochandle\n");
+return NULL;
+}
+if ((ph->core = (struct core_data*) calloc(1, sizeof(struct core_data))) == NULL) {
+free(ph);
+print_debug("can't allocate ps_prochandle\n");
+return NULL;
+}
+// initialize ph
+ph->ops = &core_ops;
+ph->core->core_fd   = -1;
+ph->core->exec_fd   = -1;
+ph->core->interp_fd = -1;
+// open the core file
+if ((ph->core->core_fd = open(core_file, O_RDONLY)) < 0) {
+print_debug("can't open core file\n");
+goto err;
+}
+// read core file ELF header
+if (read_elf_header(ph->core->core_fd, &core_ehdr) != true || core_ehdr.e_type != ET_CORE) {
+print_debug("core file is not a valid ELF ET_CORE file\n");
+goto err;
+}
+if ((ph->core->exec_fd = open(exec_file, O_RDONLY)) < 0) {
+print_debug("can't open executable file\n");
+goto err;
+}
+if (read_elf_header(ph->core->exec_fd, &exec_ehdr) != true || exec_ehdr.e_type != ET_EXEC) {
+print_debug("executable file is not a valid ELF ET_EXEC file\n");
+goto err;
+}
+// process core file segments
+if (read_core_segments(ph, &core_ehdr) != true)
+goto err;
+// process exec file segments
+if (read_exec_segments(ph, &exec_ehdr) != true)
+goto err;
+// exec file is also treated like a shared object for symbol search
+if (add_lib_info_fd(ph, exec_file, ph->core->exec_fd,
+(uintptr_t)0 + find_base_address(ph->core->exec_fd, &exec_ehdr)) == NULL)
+goto err;
+// allocate and sort maps into map_array, we need to do this
+// here because read_shared_lib_info needs to read from debuggee
+// address space
+if (sort_map_array(ph) != true)
+goto err;
+if (read_shared_lib_info(ph) != true)
+goto err;
+// sort again because we have added more mappings from shared objects
+if (sort_map_array(ph) != true)
+goto err;
+if (init_classsharing_workaround(ph) != true)
+goto err;
+return ph;
+err:
+Prelease(ph);
+return NULL;
+}

Mercurial > hg > truffle

comparison agent/src/os/bsd/ps_core.c @ 3960:f08d439fab8c