| /* |
| * 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; |
| } |