+++ /dev/null
-/** \file Libunwind namespace implementation using process_vm_readv. */
-
-/* Copyright (c) 2015-2022. The SimGrid Team. All rights reserved. */
-
-/* This program is free software; you can redistribute it and/or modify it
- * under the terms of the license (GNU LGPL) which comes with this package. */
-
-#include "src/mc/inspect/mc_unw.hpp"
-#include "src/mc/remote/RemoteProcess.hpp"
-
-#include <sys/types.h>
-#include <sys/uio.h>
-
-#include <fcntl.h>
-#include <libunwind-ptrace.h>
-#include <libunwind.h>
-
-
-/** Partial structure of libunwind-ptrace context in order to get the PID
- *
- * HACK, The context type for libunwind-race is an opaque type.
- * We need to get the PID which is the first field. This is a hack
- * which might break if the libunwind-ptrace structure changes.
- */
-struct _UPT_info {
- pid_t pid;
- // Other things...
-};
-
-/** Read from the memory, avoid using `ptrace` (libunwind method) */
-static int access_mem(const unw_addr_space_t as, const unw_word_t addr, unw_word_t* const valp, const int write,
- void* const arg)
-{
- if (write)
- return -UNW_EINVAL;
- pid_t pid = static_cast<_UPT_info*>(arg)->pid;
- size_t size = sizeof(unw_word_t);
-
-#if HAVE_PROCESS_VM_READV /* linux but not freebsd */
- // process_vm_read implementation.
- // This is only available since Linux 3.2.
-
- struct iovec local = {valp, size};
- struct iovec remote = {(void*)addr, size};
- if (ssize_t s = process_vm_readv(pid, &local, 1, &remote, 1, 0); s >= 0) {
- if ((size_t)s != size)
- return -UNW_EINVAL;
- else
- return 0;
- } else if (errno != ENOSYS) {
- return -UNW_EINVAL;
- }
-#endif
-
- // /proc/${pid}/mem implementation.
- // On recent kernels, we do not need to ptrace the target process.
- // On older kernels, it is necessary to ptrace the target process.
- size_t count = size;
- auto off = static_cast<off_t>(addr);
- auto* buf = reinterpret_cast<char*>(valp);
- int fd = simgrid::mc::open_vm(pid, O_RDONLY);
- if (fd < 0)
- return -UNW_EINVAL;
-
- while (count > 0) {
- ssize_t nread = pread(fd, buf, count, off);
- if (nread == 0) {
- close(fd);
- return -UNW_EINVAL;
- }
- if (nread == -1)
- // ptrace implementation.
- // We need to have PTRACE_ATTACH-ed it before.
- return _UPT_access_mem(as, addr, valp, write, arg);
-
- count -= nread;
- buf += nread;
- off += nread;
- }
- close(fd);
- return 0;
-}
-
-namespace simgrid::unw {
-
-unw_addr_space_t create_addr_space()
-{
- /** Virtual table for our `libunwind-process_vm_readv` implementation.
- *
- * This implementation reuse most the code of `libunwind-ptrace` but
- * does not use ptrace() to read the target process memory by
- * `process_vm_readv()` or `/dev/${pid}/mem` if possible.
- *
- * Does not support any MC-specific behavior (privatization, snapshots)
- * and `ucontext_t`.
- *
- * It works with `void*` contexts allocated with `_UPT_create(pid)`.
- */
- // TODO, we could get rid of this if we properly stop the model-checked
- // process before reading the memory.
- unw_accessors_t accessors = {&_UPT_find_proc_info, &_UPT_put_unwind_info, &_UPT_get_dyn_info_list_addr,
- &access_mem, &_UPT_access_reg, &_UPT_access_fpreg,
- &_UPT_resume, &_UPT_get_proc_name};
- return unw_create_addr_space(&accessors, BYTE_ORDER);
-}
-
-void* create_context(unw_addr_space_t /*as*/, pid_t pid)
-{
- return _UPT_create(pid);
-}
-
-} // namespace simgrid::unw
