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parasite-syscall.c
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parasite-syscall.c
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#include <unistd.h>
#include <inttypes.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/mman.h>
#include "protobuf.h"
#include "images/sa.pb-c.h"
#include "images/timer.pb-c.h"
#include "images/creds.pb-c.h"
#include "images/core.pb-c.h"
#include "images/pagemap.pb-c.h"
#include "imgset.h"
#include "ptrace.h"
#include "asm/processor-flags.h"
#include "parasite-syscall.h"
#include "parasite-blob.h"
#include "parasite.h"
#include "crtools.h"
#include "namespaces.h"
#include "kerndat.h"
#include "config.h"
#include "pstree.h"
#include "posix-timer.h"
#include "mem.h"
#include "vma.h"
#include "proc_parse.h"
#include "aio.h"
#include "fault-injection.h"
#include "syscall-codes.h"
#include <string.h>
#include <stdlib.h>
#include <elf.h>
#include "asm/parasite-syscall.h"
#include "asm/dump.h"
#include "asm/restorer.h"
#include "pie/pie-relocs.h"
#define MEMFD_FNAME "CRIUMFD"
#define MEMFD_FNAME_SZ sizeof(MEMFD_FNAME)
static int can_run_syscall(unsigned long ip, unsigned long start,
unsigned long end, unsigned long pad)
{
return ip >= start && ip < (end - BUILTIN_SYSCALL_SIZE - pad);
}
static int syscall_fits_vma_area(struct vma_area *vma_area, unsigned long pad)
{
return can_run_syscall((unsigned long)vma_area->e->start,
(unsigned long)vma_area->e->start,
(unsigned long)vma_area->e->end,
pad);
}
static struct vma_area *get_vma_by_ip(struct list_head *vma_area_list,
unsigned long ip,
unsigned long pad)
{
struct vma_area *vma_area;
list_for_each_entry(vma_area, vma_area_list, list) {
if (vma_area->e->start >= kdat.task_size)
continue;
if (!(vma_area->e->prot & PROT_EXEC))
continue;
if (syscall_fits_vma_area(vma_area, pad))
return vma_area;
}
return NULL;
}
static inline int ptrace_get_regs(int pid, user_regs_struct_t *regs)
{
struct iovec iov;
iov.iov_base = regs;
iov.iov_len = sizeof(user_regs_struct_t);
return ptrace(PTRACE_GETREGSET, pid, NT_PRSTATUS, &iov);
}
static inline int ptrace_set_regs(int pid, user_regs_struct_t *regs)
{
struct iovec iov;
iov.iov_base = regs;
iov.iov_len = sizeof(user_regs_struct_t);
return ptrace(PTRACE_SETREGSET, pid, NT_PRSTATUS, &iov);
}
static int get_thread_ctx(int pid, struct thread_ctx *ctx)
{
if (ptrace(PTRACE_GETSIGMASK, pid, sizeof(k_rtsigset_t), &ctx->sigmask)) {
pr_perror("can't get signal blocking mask for %d", pid);
return -1;
}
if (ptrace_get_regs(pid, &ctx->regs)) {
pr_perror("Can't obtain registers (pid: %d)", pid);
return -1;
}
return 0;
}
static int restore_thread_ctx(int pid, struct thread_ctx *ctx)
{
int ret = 0;
if (ptrace_set_regs(pid, &ctx->regs)) {
pr_perror("Can't restore registers (pid: %d)", pid);
ret = -1;
}
if (ptrace(PTRACE_SETSIGMASK, pid, sizeof(k_rtsigset_t), &ctx->sigmask)) {
pr_perror("Can't block signals");
ret = -1;
}
return ret;
}
static int parasite_run(pid_t pid, int cmd, unsigned long ip, void *stack,
user_regs_struct_t *regs, struct thread_ctx *octx)
{
k_rtsigset_t block;
ksigfillset(&block);
if (ptrace(PTRACE_SETSIGMASK, pid, sizeof(k_rtsigset_t), &block)) {
pr_perror("Can't block signals for %d", pid);
goto err_sig;
}
parasite_setup_regs(ip, stack, regs);
if (ptrace_set_regs(pid, regs)) {
pr_perror("Can't set registers for %d", pid);
goto err_regs;
}
if (ptrace(cmd, pid, NULL, NULL)) {
pr_perror("Can't run parasite at %d", pid);
goto err_cont;
}
return 0;
err_cont:
if (ptrace_set_regs(pid, &octx->regs))
pr_perror("Can't restore regs for %d", pid);
err_regs:
if (ptrace(PTRACE_SETSIGMASK, pid, sizeof(k_rtsigset_t), &octx->sigmask))
pr_perror("Can't restore sigmask for %d", pid);
err_sig:
return -1;
}
/* we run at @regs->ip */
static int parasite_trap(struct parasite_ctl *ctl, pid_t pid,
user_regs_struct_t *regs,
struct thread_ctx *octx)
{
siginfo_t siginfo;
int status;
int ret = -1;
/*
* Most ideas are taken from Tejun Heo's parasite thread
* https://code.google.com/p/ptrace-parasite/
*/
if (wait4(pid, &status, __WALL, NULL) != pid) {
pr_perror("Waited pid mismatch (pid: %d)", pid);
goto err;
}
if (!WIFSTOPPED(status)) {
pr_err("Task is still running (pid: %d)\n", pid);
goto err;
}
if (ptrace(PTRACE_GETSIGINFO, pid, NULL, &siginfo)) {
pr_perror("Can't get siginfo (pid: %d)", pid);
goto err;
}
if (ptrace_get_regs(pid, regs)) {
pr_perror("Can't obtain registers (pid: %d)", pid);
goto err;
}
if (WSTOPSIG(status) != SIGTRAP || siginfo.si_code != ARCH_SI_TRAP) {
pr_debug("** delivering signal %d si_code=%d\n",
siginfo.si_signo, siginfo.si_code);
pr_err("Unexpected %d task interruption, aborting\n", pid);
goto err;
}
/*
* We've reached this point if int3 is triggered inside our
* parasite code. So we're done.
*/
ret = 0;
err:
if (restore_thread_ctx(pid, octx))
ret = -1;
return ret;
}
int __parasite_execute_syscall(struct parasite_ctl *ctl,
user_regs_struct_t *regs, const char *code_syscall)
{
pid_t pid = ctl->pid.real;
int err;
u8 code_orig[BUILTIN_SYSCALL_SIZE];
/*
* Inject syscall instruction and remember original code,
* we will need it to restore original program content.
*/
memcpy(code_orig, code_syscall, sizeof(code_orig));
if (ptrace_swap_area(pid, (void *)ctl->syscall_ip,
(void *)code_orig, sizeof(code_orig))) {
pr_err("Can't inject syscall blob (pid: %d)\n", pid);
return -1;
}
err = parasite_run(pid, PTRACE_CONT, ctl->syscall_ip, 0, regs, &ctl->orig);
if (!err)
err = parasite_trap(ctl, pid, regs, &ctl->orig);
if (ptrace_poke_area(pid, (void *)code_orig,
(void *)ctl->syscall_ip, sizeof(code_orig))) {
pr_err("Can't restore syscall blob (pid: %d)\n", ctl->pid.real);
err = -1;
}
return err;
}
void *parasite_args_s(struct parasite_ctl *ctl, int args_size)
{
BUG_ON(args_size > ctl->args_size);
return ctl->addr_args;
}
static int parasite_execute_trap_by_pid(unsigned int cmd,
struct parasite_ctl *ctl, pid_t pid,
void *stack,
struct thread_ctx *octx)
{
user_regs_struct_t regs = octx->regs;
int ret;
*ctl->addr_cmd = cmd;
ret = parasite_run(pid, PTRACE_CONT, ctl->parasite_ip, stack, ®s, octx);
if (ret == 0)
ret = parasite_trap(ctl, pid, ®s, octx);
if (ret == 0)
ret = (int)REG_RES(regs);
if (ret)
pr_err("Parasite exited with %d\n", ret);
return ret;
}
static int __parasite_send_cmd(int sockfd, struct ctl_msg *m)
{
int ret;
ret = send(sockfd, m, sizeof(*m), 0);
if (ret == -1) {
pr_perror("Failed to send command %d to daemon", m->cmd);
return -1;
} else if (ret != sizeof(*m)) {
pr_err("Message to daemon is trimmed (%d/%d)\n",
(int)sizeof(*m), ret);
return -1;
}
pr_debug("Sent msg to daemon %d %d %d\n", m->cmd, m->ack, m->err);
return 0;
}
static int parasite_wait_ack(int sockfd, unsigned int cmd, struct ctl_msg *m)
{
int ret;
pr_debug("Wait for ack %d on daemon socket\n", cmd);
while (1) {
memzero(m, sizeof(*m));
ret = recv(sockfd, m, sizeof(*m), MSG_WAITALL);
if (ret == -1) {
pr_perror("Failed to read ack");
return -1;
} else if (ret != sizeof(*m)) {
pr_err("Message reply from daemon is trimmed (%d/%d)\n",
(int)sizeof(*m), ret);
return -1;
}
pr_debug("Fetched ack: %d %d %d\n",
m->cmd, m->ack, m->err);
if (m->cmd != cmd || m->ack != cmd) {
pr_err("Communication error, this is not "
"the ack we expected\n");
return -1;
}
return 0;
}
return -1;
}
int __parasite_wait_daemon_ack(unsigned int cmd,
struct parasite_ctl *ctl)
{
struct ctl_msg m;
if (parasite_wait_ack(ctl->tsock, cmd, &m))
return -1;
if (m.err != 0) {
pr_err("Command %d for daemon failed with %d\n",
cmd, m.err);
return -1;
}
return 0;
}
int __parasite_execute_daemon(unsigned int cmd, struct parasite_ctl *ctl)
{
struct ctl_msg m;
m = ctl_msg_cmd(cmd);
return __parasite_send_cmd(ctl->tsock, &m);
}
int parasite_execute_daemon(unsigned int cmd, struct parasite_ctl *ctl)
{
int ret;
ret = __parasite_execute_daemon(cmd, ctl);
if (!ret)
ret = __parasite_wait_daemon_ack(cmd, ctl);
return ret;
}
static int gen_parasite_saddr(struct sockaddr_un *saddr, int key)
{
int sun_len;
saddr->sun_family = AF_UNIX;
snprintf(saddr->sun_path, UNIX_PATH_MAX,
"X/crtools-pr-%d", key);
sun_len = SUN_LEN(saddr);
*saddr->sun_path = '\0';
return sun_len;
}
int parasite_send_fd(struct parasite_ctl *ctl, int fd)
{
if (send_fd(ctl->tsock, NULL, 0, fd) < 0) {
pr_perror("Can't send file descriptor");
return -1;
}
return 0;
}
/*
* We need to detect parasite crashes not to hang on socket operations.
* Since CRIU holds parasite with ptrace, it will receive SIGCHLD if the
* latter would crash.
*
* This puts a restriction on how to execute a sub-process on dump stage.
* One should use the cr_system helper, that blocks sigcild and waits
* for the spawned program to finish.
*/
static void sigchld_handler(int signal, siginfo_t *siginfo, void *data)
{
int pid, status;
pid = waitpid(-1, &status, WNOHANG);
if (pid <= 0)
return;
pr_err("si_code=%d si_pid=%d si_status=%d\n",
siginfo->si_code, siginfo->si_pid, siginfo->si_status);
if (WIFEXITED(status))
pr_err("%d exited with %d unexpectedly\n", pid, WEXITSTATUS(status));
else if (WIFSIGNALED(status))
pr_err("%d was killed by %d unexpectedly: %s\n",
pid, WTERMSIG(status), strsignal(WTERMSIG(status)));
else if (WIFSTOPPED(status))
pr_err("%d was stopped by %d unexpectedly\n", pid, WSTOPSIG(status));
exit(1);
}
static int setup_child_handler()
{
struct sigaction sa = {
.sa_sigaction = sigchld_handler,
.sa_flags = SA_SIGINFO | SA_RESTART,
};
sigemptyset(&sa.sa_mask);
sigaddset(&sa.sa_mask, SIGCHLD);
if (sigaction(SIGCHLD, &sa, NULL)) {
pr_perror("Unable to setup SIGCHLD handler");
return -1;
}
return 0;
}
static int restore_child_handler()
{
struct sigaction sa = {
.sa_handler = SIG_DFL,
.sa_flags = SA_SIGINFO | SA_RESTART,
};
sigemptyset(&sa.sa_mask);
sigaddset(&sa.sa_mask, SIGCHLD);
if (sigaction(SIGCHLD, &sa, NULL)) {
pr_perror("Unable to setup SIGCHLD handler");
return -1;
}
return 0;
}
static int prepare_tsock(struct parasite_ctl *ctl, pid_t pid,
struct parasite_init_args *args, struct ns_id *net)
{
static int ssock = -1;
pr_info("Putting tsock into pid %d\n", pid);
args->h_addr_len = gen_parasite_saddr(&args->h_addr, getpid());
if (ssock == -1) {
ssock = net->net.seqsk;
net->net.seqsk = -1;
if (bind(ssock, (struct sockaddr *)&args->h_addr, args->h_addr_len) < 0) {
pr_perror("Can't bind socket");
goto err;
}
if (listen(ssock, 1)) {
pr_perror("Can't listen on transport socket");
goto err;
}
}
/* Check a case when parasite can't initialize a command socket */
if (fault_injected(FI_PARASITE_CONNECT))
args->h_addr_len = gen_parasite_saddr(&args->h_addr, getpid() + 1);
/*
* Set to -1 to prevent any accidental misuse. The
* only valid user of it is accept_tsock().
*/
ctl->tsock = -ssock;
return 0;
err:
close_safe(&ssock);
return -1;
}
static int accept_tsock(struct parasite_ctl *ctl)
{
int sock;
int ask = -ctl->tsock; /* this '-' is explained above */
sock = accept(ask, NULL, 0);
if (sock < 0) {
pr_perror("Can't accept connection to the transport socket");
close(ask);
return -1;
}
ctl->tsock = sock;
return 0;
}
static int parasite_init_daemon(struct parasite_ctl *ctl, struct ns_id *net)
{
struct parasite_init_args *args;
pid_t pid = ctl->pid.real;
user_regs_struct_t regs;
struct ctl_msg m = { };
*ctl->addr_cmd = PARASITE_CMD_INIT_DAEMON;
args = parasite_args(ctl, struct parasite_init_args);
args->sigframe = ctl->rsigframe;
args->log_level = log_get_loglevel();
futex_set(&args->daemon_connected, 0);
if (prepare_tsock(ctl, pid, args, net))
goto err;
/* after this we can catch parasite errors in chld handler */
if (setup_child_handler())
goto err;
regs = ctl->orig.regs;
if (parasite_run(pid, PTRACE_CONT, ctl->parasite_ip, ctl->rstack, ®s, &ctl->orig))
goto err;
futex_wait_while_eq(&args->daemon_connected, 0);
if (futex_get(&args->daemon_connected) != 1) {
errno = -(int)futex_get(&args->daemon_connected);
pr_perror("Unable to connect a transport socket");
goto err;
}
if (accept_tsock(ctl) < 0)
goto err;
if (parasite_send_fd(ctl, log_get_fd()))
goto err;
pr_info("Wait for parasite being daemonized...\n");
if (parasite_wait_ack(ctl->tsock, PARASITE_CMD_INIT_DAEMON, &m)) {
pr_err("Can't switch parasite %d to daemon mode %d\n",
pid, m.err);
goto err;
}
ctl->sigreturn_addr = args->sigreturn_addr;
ctl->daemonized = true;
pr_info("Parasite %d has been switched to daemon mode\n", pid);
return 0;
err:
return -1;
}
static int alloc_groups_copy_creds(CredsEntry *ce, struct parasite_dump_creds *c)
{
BUILD_BUG_ON(sizeof(ce->groups[0]) != sizeof(c->groups[0]));
BUILD_BUG_ON(sizeof(ce->cap_inh[0]) != sizeof(c->cap_inh[0]));
BUILD_BUG_ON(sizeof(ce->cap_prm[0]) != sizeof(c->cap_prm[0]));
BUILD_BUG_ON(sizeof(ce->cap_eff[0]) != sizeof(c->cap_eff[0]));
BUILD_BUG_ON(sizeof(ce->cap_bnd[0]) != sizeof(c->cap_bnd[0]));
BUG_ON(ce->n_cap_inh != CR_CAP_SIZE);
BUG_ON(ce->n_cap_prm != CR_CAP_SIZE);
BUG_ON(ce->n_cap_eff != CR_CAP_SIZE);
BUG_ON(ce->n_cap_bnd != CR_CAP_SIZE);
memcpy(ce->cap_inh, c->cap_inh, sizeof(c->cap_inh[0]) * CR_CAP_SIZE);
memcpy(ce->cap_prm, c->cap_prm, sizeof(c->cap_prm[0]) * CR_CAP_SIZE);
memcpy(ce->cap_eff, c->cap_eff, sizeof(c->cap_eff[0]) * CR_CAP_SIZE);
memcpy(ce->cap_bnd, c->cap_bnd, sizeof(c->cap_bnd[0]) * CR_CAP_SIZE);
ce->secbits = c->secbits;
ce->n_groups = c->ngroups;
ce->groups = xmemdup(c->groups, sizeof(c->groups[0]) * c->ngroups);
ce->uid = c->uids[0];
ce->gid = c->gids[0];
ce->euid = c->uids[1];
ce->egid = c->gids[1];
ce->suid = c->uids[2];
ce->sgid = c->gids[2];
ce->fsuid = c->uids[3];
ce->fsgid = c->gids[3];
return ce->groups ? 0 : -ENOMEM;
}
int parasite_dump_thread_leader_seized(struct parasite_ctl *ctl, int pid, CoreEntry *core)
{
ThreadCoreEntry *tc = core->thread_core;
struct parasite_dump_thread *args;
struct parasite_dump_creds *pc;
int ret;
args = parasite_args(ctl, struct parasite_dump_thread);
pc = args->creds;
pc->cap_last_cap = kdat.last_cap;
ret = parasite_execute_daemon(PARASITE_CMD_DUMP_THREAD, ctl);
if (ret < 0)
return ret;
ret = alloc_groups_copy_creds(tc->creds, pc);
if (ret) {
pr_err("Can't copy creds for thread leader %d\n", pid);
return -1;
}
return dump_thread_core(pid, core, args);
}
int parasite_dump_thread_seized(struct parasite_ctl *ctl, int id,
struct pid *tid, CoreEntry *core)
{
struct parasite_dump_thread *args;
pid_t pid = tid->real;
ThreadCoreEntry *tc = core->thread_core;
CredsEntry *creds = tc->creds;
struct parasite_dump_creds *pc;
int ret;
struct thread_ctx octx;
BUG_ON(id == 0); /* Leader is dumped in dump_task_core_all */
args = parasite_args(ctl, struct parasite_dump_thread);
pc = args->creds;
pc->cap_last_cap = kdat.last_cap;
ret = get_thread_ctx(pid, &octx);
if (ret)
return -1;
tc->has_blk_sigset = true;
memcpy(&tc->blk_sigset, &octx.sigmask, sizeof(k_rtsigset_t));
ret = parasite_execute_trap_by_pid(PARASITE_CMD_DUMP_THREAD, ctl,
pid, ctl->r_thread_stack, &octx);
if (ret) {
pr_err("Can't init thread in parasite %d\n", pid);
return -1;
}
ret = alloc_groups_copy_creds(creds, pc);
if (ret) {
pr_err("Can't copy creds for thread %d\n", pid);
return -1;
}
ret = get_task_regs(pid, octx.regs, core);
if (ret) {
pr_err("Can't obtain regs for thread %d\n", pid);
return -1;
}
tid->virt = args->tid;
return dump_thread_core(pid, core, args);
}
int parasite_dump_sigacts_seized(struct parasite_ctl *ctl, struct cr_imgset *cr_imgset)
{
struct parasite_dump_sa_args *args;
int ret, sig;
struct cr_img *img;
SaEntry se = SA_ENTRY__INIT;
args = parasite_args(ctl, struct parasite_dump_sa_args);
ret = parasite_execute_daemon(PARASITE_CMD_DUMP_SIGACTS, ctl);
if (ret < 0)
return ret;
img = img_from_set(cr_imgset, CR_FD_SIGACT);
for (sig = 1; sig <= SIGMAX; sig++) {
int i = sig - 1;
if (sig == SIGSTOP || sig == SIGKILL)
continue;
ASSIGN_TYPED(se.sigaction, encode_pointer(args->sas[i].rt_sa_handler));
ASSIGN_TYPED(se.flags, args->sas[i].rt_sa_flags);
ASSIGN_TYPED(se.restorer, encode_pointer(args->sas[i].rt_sa_restorer));
BUILD_BUG_ON(sizeof(se.mask) != sizeof(args->sas[0].rt_sa_mask.sig));
memcpy(&se.mask, args->sas[i].rt_sa_mask.sig, sizeof(se.mask));
if (pb_write_one(img, &se, PB_SIGACT) < 0)
return -1;
}
return 0;
}
static void encode_itimer(struct itimerval *v, ItimerEntry *ie)
{
ie->isec = v->it_interval.tv_sec;
ie->iusec = v->it_interval.tv_usec;
ie->vsec = v->it_value.tv_sec;
ie->vusec = v->it_value.tv_usec;
}
int parasite_dump_itimers_seized(struct parasite_ctl *ctl, struct pstree_item *item)
{
CoreEntry *core = item->core[0];
struct parasite_dump_itimers_args *args;
int ret;
args = parasite_args(ctl, struct parasite_dump_itimers_args);
ret = parasite_execute_daemon(PARASITE_CMD_DUMP_ITIMERS, ctl);
if (ret < 0)
return ret;
encode_itimer(&args->real, core->tc->timers->real);
encode_itimer(&args->virt, core->tc->timers->virt);
encode_itimer(&args->prof, core->tc->timers->prof);
return 0;
}
static void encode_posix_timer(struct posix_timer *v, struct proc_posix_timer *vp, PosixTimerEntry *pte)
{
pte->it_id = vp->spt.it_id;
pte->clock_id = vp->spt.clock_id;
pte->si_signo = vp->spt.si_signo;
pte->it_sigev_notify = vp->spt.it_sigev_notify;
pte->sival_ptr = encode_pointer(vp->spt.sival_ptr);
pte->overrun = v->overrun;
pte->isec = v->val.it_interval.tv_sec;
pte->insec = v->val.it_interval.tv_nsec;
pte->vsec = v->val.it_value.tv_sec;
pte->vnsec = v->val.it_value.tv_nsec;
}
static int core_alloc_posix_timers(TaskTimersEntry *tte, int n,
PosixTimerEntry **pte)
{
int sz;
/*
* Will be free()-ed in core_entry_free()
*/
sz = n * (sizeof(PosixTimerEntry *) + sizeof(PosixTimerEntry));
tte->posix = xmalloc(sz);
if (!tte->posix)
return -1;
tte->n_posix = n;
*pte = (PosixTimerEntry *)(tte->posix + n);
return 0;
}
int parasite_dump_posix_timers_seized(struct proc_posix_timers_stat *proc_args,
struct parasite_ctl *ctl, struct pstree_item *item)
{
CoreEntry *core = item->core[0];
TaskTimersEntry *tte = core->tc->timers;
PosixTimerEntry *pte;
struct parasite_dump_posix_timers_args * args;
struct proc_posix_timer *temp;
int i;
int ret = 0;
if (core_alloc_posix_timers(tte, proc_args->timer_n, &pte))
return -1;
args = parasite_args_s(ctl, posix_timers_dump_size(proc_args->timer_n));
args->timer_n = proc_args->timer_n;
i = 0;
list_for_each_entry(temp, &proc_args->timers, list) {
args->timer[i].it_id = temp->spt.it_id;
i++;
}
ret = parasite_execute_daemon(PARASITE_CMD_DUMP_POSIX_TIMERS, ctl);
if (ret < 0)
goto end_posix;
i = 0;
list_for_each_entry(temp, &proc_args->timers, list) {
posix_timer_entry__init(&pte[i]);
encode_posix_timer(&args->timer[i], temp, &pte[i]);
tte->posix[i] = &pte[i];
i++;
}
end_posix:
free_posix_timers(proc_args);
return ret;
}
int parasite_dump_misc_seized(struct parasite_ctl *ctl, struct parasite_dump_misc *misc)
{
struct parasite_dump_misc *ma;
ma = parasite_args(ctl, struct parasite_dump_misc);
if (parasite_execute_daemon(PARASITE_CMD_DUMP_MISC, ctl) < 0)
return -1;
*misc = *ma;
return 0;
}
struct parasite_tty_args *parasite_dump_tty(struct parasite_ctl *ctl, int fd, int type)
{
struct parasite_tty_args *p;
p = parasite_args(ctl, struct parasite_tty_args);
p->fd = fd;
p->type = type;
if (parasite_execute_daemon(PARASITE_CMD_DUMP_TTY, ctl) < 0)
return NULL;
return p;
}
int parasite_drain_fds_seized(struct parasite_ctl *ctl,
struct parasite_drain_fd *dfds, int nr_fds, int off,
int *lfds, struct fd_opts *opts)
{
int ret = -1, size;
struct parasite_drain_fd *args;
size = drain_fds_size(dfds);
args = parasite_args_s(ctl, size);
args->nr_fds = nr_fds;
memcpy(&args->fds, dfds->fds + off, sizeof(int) * nr_fds);
ret = __parasite_execute_daemon(PARASITE_CMD_DRAIN_FDS, ctl);
if (ret) {
pr_err("Parasite failed to drain descriptors\n");
goto err;
}
ret = recv_fds(ctl->tsock, lfds, nr_fds, opts);
if (ret)
pr_err("Can't retrieve FDs from socket\n");
ret |= __parasite_wait_daemon_ack(PARASITE_CMD_DRAIN_FDS, ctl);
err:
return ret;
}
int parasite_get_proc_fd_seized(struct parasite_ctl *ctl)
{
int ret = -1, fd;
ret = __parasite_execute_daemon(PARASITE_CMD_GET_PROC_FD, ctl);
if (ret) {
pr_err("Parasite failed to get proc fd\n");
return ret;
}
fd = recv_fd(ctl->tsock);
if (fd < 0)
pr_err("Can't retrieve FD from socket\n");
if (__parasite_wait_daemon_ack(PARASITE_CMD_GET_PROC_FD, ctl)) {
close_safe(&fd);
return -1;
}
return fd;
}
/* This is officially the 50000'th line in the CRIU source code */
static bool task_in_parasite(struct parasite_ctl *ctl, user_regs_struct_t *regs)
{
void *addr = (void *) REG_IP(*regs);
return addr >= ctl->remote_map &&
addr < ctl->remote_map + ctl->map_length;
}
static int parasite_fini_seized(struct parasite_ctl *ctl)
{
pid_t pid = ctl->pid.real;
user_regs_struct_t regs;
int status, ret = 0;
enum trace_flags flag;
/* stop getting chld from parasite -- we're about to step-by-step it */
if (restore_child_handler())
return -1;
/* Start to trace syscalls for each thread */
if (ptrace(PTRACE_INTERRUPT, pid, NULL, NULL)) {
pr_perror("Unable to interrupt the process");
return -1;
}
pr_debug("Waiting for %d to trap\n", pid);
if (wait4(pid, &status, __WALL, NULL) != pid) {
pr_perror("Waited pid mismatch (pid: %d)", pid);
return -1;
}
pr_debug("Daemon %d exited trapping\n", pid);
if (!WIFSTOPPED(status)) {
pr_err("Task is still running (pid: %d)\n", pid);
return -1;
}
ret = ptrace_get_regs(pid, ®s);
if (ret) {
pr_perror("Unable to get registers");
return -1;
}
if (!task_in_parasite(ctl, ®s)) {
pr_err("The task is not in parasite code\n");
return -1;
}
ret = __parasite_execute_daemon(PARASITE_CMD_FINI, ctl);
close_safe(&ctl->tsock);
if (ret)
return -1;
/* Go to sigreturn as closer as we can */
ret = ptrace_stop_pie(pid, ctl->sigreturn_addr, &flag);
if (ret < 0)
return ret;
if (parasite_stop_on_syscall(1, __NR_rt_sigreturn, flag))
return -1;
if (ptrace_flush_breakpoints(pid))
return -1;
/*
* All signals are unblocked now. The kernel notifies about leaving
* syscall before starting to deliver signals. All parasite code are
* executed with blocked signals, so we can sefly unmap a parasite blob.
*/
return 0;
}
static bool task_is_trapped(int status, pid_t pid)
{
if (WIFSTOPPED(status) && WSTOPSIG(status) == SIGTRAP)
return true;
pr_err("Task %d is in unexpected state: %x\n", pid, status);
if (WIFEXITED(status))
pr_err("Task exited with %d\n", WEXITSTATUS(status));
if (WIFSIGNALED(status))
pr_err("Task signaled with %d: %s\n",
WTERMSIG(status), strsignal(WTERMSIG(status)));
if (WIFSTOPPED(status))
pr_err("Task stopped with %d: %s\n",
WSTOPSIG(status), strsignal(WSTOPSIG(status)));
if (WIFCONTINUED(status))
pr_err("Task continued\n");
return false;
}
/*
* Trap tasks on the exit from the specified syscall
*
* tasks - number of processes, which should be trapped
* sys_nr - the required syscall number
*/
int parasite_stop_on_syscall(int tasks, const int sys_nr, enum trace_flags trace)
{
user_regs_struct_t regs;
int status, ret;
pid_t pid;
if (tasks > 1)
trace = TRACE_ALL;
/* Stop all threads on the enter point in sys_rt_sigreturn */
while (tasks) {
pid = wait4(-1, &status, __WALL, NULL);
if (pid == -1) {
pr_perror("wait4 failed");
return -1;
}
if (!task_is_trapped(status, pid))
return -1;
pr_debug("%d was trapped\n", pid);
if (trace == TRACE_EXIT) {
trace = TRACE_ENTER;
pr_debug("`- Expecting exit\n");