int copy_memory(int pid, struct mem_data_chunk **frames, int n_frames)
{
if (!opt_proc_mem) {
int rc = copy_memory_process_vm_readv(pid, frames, n_frames);
if (rc == ENOSYS) {
if (opt_verbose) {
fprintf(stderr, "process_vm_readv is not supported, falling "
"back to /proc/pid/mem\n");
}
} else {
return rc;
}
}
return copy_memory_proc_mem(pid, frames, n_frames);
}
/*
* save process' memory maps, stack contents, thread identifiers and registers
*/
struct snapshot *get_snapshot(int pid, int *tids, int *index, int nr_tids)
{
struct snapshot *res;
int i, attached_tid, n_frames;
long page, label, rc;
struct mem_data_chunk **stacks_cover = NULL;
int v_major, v_minor;
int use_process_vm_readv = 0;
if ((page = sysconf(_SC_PAGESIZE)) < 0) {
perror("get pagesize");
return NULL;
}
--page;
res = calloc(1, sizeof(struct snapshot));
/*
* create memory_map structure corresponding to process' maps
*/
res->map = create_maps(pid);
if (res->map == NULL)
goto get_snapshot_fail;
/*
* get process' threads
*/
res->num_threads = get_threads(pid, &res->tids);
if (res->num_threads < 0 || res->tids == NULL)
goto get_snapshot_fail;
/*
* user-provided list of threads
*/
if (tids != NULL) {
if (adjust_threads(res->tids, res->num_threads, tids, index, nr_tids) < 0)
goto get_snapshot_fail;
free(res->tids);
res->num_threads = nr_tids;
res->tids = tids;
}
res->cur_thr = 0;
res->regs = malloc(sizeof(struct user_regs_struct)*res->num_threads);
if (res->regs == NULL) {
perror("malloc");
goto get_snapshot_fail;
}
/*
* decide how to copy memory contents of the process. on newer kernels
* proc_vm_readv() is used by default. on older kernels or when the option
* --proc-mem is specified read the file /proc/<pid>/mem
*/
if (!opt_proc_mem) {
if (get_kernel_version(&v_major, &v_minor) < 0)
goto get_snapshot_fail;
if (((v_major << 16) | v_minor) >= 0x30002)
use_process_vm_readv = 1;
} else {
use_process_vm_readv = 0;
}
/* FREEZE PROCESS */
if (attach_process(pid) < 0)
goto get_snapshot_fail;
for (i = 0; i < res->num_threads; ++i) {
/*
* we have already attached to main thread. call attach_thread()
* for other ones
*/
attached_tid = res->tids[i];
if (res->tids[i] != pid && attach_thread(res->tids[i]) < 0)
goto get_snapshot_fail_attached;
/*
* save thread's registers
*/
rc = ptrace(PTRACE_GETREGS, res->tids[i], NULL, &res->regs[i]);
if (rc < 0) {
perror("PTRACE_GETREGS");
goto get_snapshot_fail_attached;
}
/*
* save label on memory region. it will indicate that memory contents
* upper than this point (%rsp) will needed to unwind stacks
*/
label = res->regs[i].rsp & ~page;
rc = mem_map_add_label(res->map, (void *)label, res->num_threads);
if (rc < 0) {
fprintf(stderr, "failed to add label 0x%lx [rsp 0x%lx thread %d]\n",
label, res->regs[i].rsp, res->tids[i]);
goto get_snapshot_fail_attached;
}
/*
* detach from thread. it will still be frozen due to SIGSTOP
*/
if (res->tids[i] != pid && detach_thread(res->tids[i]) < 0)
goto get_snapshot_fail_attached;
}
/*
* arrange data chunks to copy memory contents. in most cases the chunks
* will start from %rsp pointing somewhere in thread's stack
* to the end of the stack region
*/
stacks_cover = malloc(sizeof(struct mem_data_chunk*) * res->num_threads);
n_frames = mem_map_build_label_cover(res->map, stack_size,
stacks_cover, page + 1);
if (stacks_cover == NULL) {
fprintf(stderr, "error: stacks cover == NULL, n_frames=%d\n", n_frames);
goto get_snapshot_fail_attached;
}
/*
* copy memory contents
*/
rc = use_process_vm_readv ?
copy_memory_process_vm_readv(pid, stacks_cover, n_frames) :
copy_memory_proc_mem(pid, stacks_cover, n_frames);
if (rc < 0)
goto get_snapshot_fail_attached;
/* UNFREEZE PROCESS */
if (detach_process(pid) < 0)
goto get_snapshot_fail;
if (opt_verbose) {
for (i = 0; i < n_frames; ++i) {
struct mem_data_chunk *chunk = stacks_cover[i];
printf("chunk #%d: 0x%lx-0x%lx length: %ldK\n",
i, (size_t)chunk->start,
(size_t)chunk->start + chunk->length,
chunk->length >> 10);
}
}
free(stacks_cover);
return res;
get_snapshot_fail_attached:
if (attached_tid)
detach_thread(attached_tid);
detach_process(pid);
get_snapshot_fail:
if (opt_verbose) {
fprintf(stderr, "maps of %d:\n", pid);
print_proc_maps(pid);
}
free(stacks_cover);
snapshot_destroy(res);
return NULL;
}