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criu/compel/plugins/std/infect.c

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#include <compel/plugins/std.h>
#include "common/scm.h"
#include "common/compiler.h"
#include "common/lock.h"
#include "common/page.h"
#define pr_err(fmt, ...) print_on_level(1, fmt, ##__VA_ARGS__)
#define pr_info(fmt, ...) print_on_level(3, fmt, ##__VA_ARGS__)
#define pr_debug(fmt, ...) print_on_level(4, fmt, ##__VA_ARGS__)
#include "common/bug.h"
#include "uapi/compel/asm/sigframe.h"
#include "uapi/compel/infect-rpc.h"
#include "rpc-pie-priv.h"
#ifndef ARCH_RT_SIGRETURN_DUMP
#define ARCH_RT_SIGRETURN_DUMP ARCH_RT_SIGRETURN
#endif
static int tsock = -1;
static struct rt_sigframe *sigframe;
#ifdef ARCH_HAS_LONG_PAGES
/*
* XXX: Make it compel's std plugin global variable. Drop parasite_size().
* Hint: compel on aarch64 shall learn relocs for that.
*/
static unsigned __page_size;
unsigned long __attribute((weak)) page_size(void)
{
return __page_size;
}
#endif
int parasite_get_rpc_sock(void)
{
return tsock;
}
/* RPC helpers */
static int __parasite_daemon_reply_ack(unsigned int cmd, int err)
{
struct ctl_msg m;
int ret;
m = ctl_msg_ack(cmd, err);
ret = sys_sendto(tsock, &m, sizeof(m), 0, NULL, 0);
if (ret != sizeof(m)) {
pr_err("Sent only %d bytes while %zu expected\n", ret, sizeof(m));
return -1;
}
pr_debug("__sent ack msg: %d %d %d\n", m.cmd, m.ack, m.err);
return 0;
}
static int __parasite_daemon_wait_msg(struct ctl_msg *m)
{
int ret;
pr_debug("Daemon waits for command\n");
while (1) {
*m = (struct ctl_msg){};
ret = sys_recvfrom(tsock, m, sizeof(*m), MSG_WAITALL, NULL, 0);
if (ret != sizeof(*m)) {
pr_err("Trimmed message received (%d/%d)\n", (int)sizeof(*m), ret);
return -1;
}
pr_debug("__fetched msg: %d %d %d\n", m->cmd, m->ack, m->err);
return 0;
}
return -1;
}
/* Core infect code */
static noinline unsigned long fini_sigreturn(unsigned long new_sp)
{
ARCH_RT_SIGRETURN_DUMP(new_sp, sigframe);
return new_sp;
}
static unsigned long fini(void)
{
unsigned long new_sp;
parasite_cleanup();
new_sp = (long)sigframe + RT_SIGFRAME_OFFSET(sigframe);
pr_debug("%ld: new_sp=%lx ip %lx\n", sys_gettid(), new_sp, RT_SIGFRAME_REGIP(sigframe));
sys_close(tsock);
std_log_set_fd(-1);
return fini_sigreturn(new_sp);
BUG();
return -1;
}
static noinline __used unsigned long parasite_daemon(void *args)
{
struct ctl_msg m;
int ret = -1;
pr_debug("Running daemon thread leader\n");
/* Reply we're alive */
if (__parasite_daemon_reply_ack(PARASITE_CMD_INIT_DAEMON, 0))
goto out;
ret = 0;
while (1) {
if (__parasite_daemon_wait_msg(&m))
break;
if (ret && m.cmd != PARASITE_CMD_FINI) {
pr_err("Command rejected\n");
continue;
}
if (m.cmd == PARASITE_CMD_FINI)
goto out;
ret = parasite_daemon_cmd(m.cmd, args);
if (__parasite_daemon_reply_ack(m.cmd, ret))
break;
if (ret) {
pr_err("Close the control socket for writing\n");
sys_shutdown(tsock, SHUT_WR);
}
}
out:
return fini();
}
static noinline __used unsigned long parasite_init_daemon(void *data)
{
struct parasite_init_args *args = data;
int ret;
args->sigreturn_addr = (uint64_t)(uintptr_t)fini_sigreturn;
sigframe = (void *)(uintptr_t)args->sigframe;
#ifdef ARCH_HAS_LONG_PAGES
__page_size = args->page_size;
#endif
ret = tsock = sys_socket(PF_UNIX, SOCK_SEQPACKET, 0);
if (tsock < 0) {
pr_err("Can't create socket: %d\n", tsock);
goto err;
}
ret = sys_connect(tsock, (struct sockaddr *)&args->h_addr, args->h_addr_len);
if (ret < 0) {
pr_err("Can't connect the control socket\n");
goto err;
}
futex_set_and_wake(&args->daemon_connected, 1);
ret = recv_fd(tsock);
if (ret >= 0) {
std_log_set_fd(ret);
std_log_set_loglevel(args->log_level);
ret = 0;
} else
goto err;
return parasite_daemon(data);
err:
futex_set_and_wake(&args->daemon_connected, ret);
return fini();
}
#ifndef __parasite_entry
#define __parasite_entry
#endif
/*
* __export_parasite_service_{cmd,args} serve as arguments to the
* parasite_service() function. We use these global variables to make it
* easier to pass arguments when invoking from ptrace.
*
* We need the linker to allocate these variables. Hence the dummy
* initialization. Otherwise, we end up with COMMON symbols.
*/
unsigned int __export_parasite_service_cmd = 0;
void *__export_parasite_service_args_ptr = NULL;
unsigned long __used __parasite_entry parasite_service(void)
{
unsigned int cmd = __export_parasite_service_cmd;
void *args = __export_parasite_service_args_ptr;
pr_info("Parasite cmd %d/%x process\n", cmd, cmd);
compel: kill self-unmap in parasite Why should we have self-unmapping code in parasite? It looks like, we can drop this code using simple sys_unmap() injection (like that I did for `criu exec` action and for cases where we failed to insert parasite by some reason, but still need to unmap remotes). It's an RFC, so just a suggestion - maybe I miss something you have in mind - please, describe that/those things. My motivation is: - less code, defined commands for PIE, one BUG() less, one jump to PIE less - I'm making one 64-bit parasite on x86 instead of two 32 and 64 bit. It works (branch 32-one-parasite) with long-jump in the beginning to 64-bit code from 32-bit task. On parasite curing it sig-returns from 64-bit parasite to 32-bit task, this point we're trapping in CRIU. After that we command parasite to unmap itself, so it long-jumps again to parasite 64-bit code, unmaps, we caught task after sys_unmap and the task is with 64-bit CS. We can't set 32-bit registers after this - kernel checks that registers set is the same on PTRACE_SETREGSET: > > static int ptrace_regset(struct task_struct *task, int req, unsigned int type, > > struct iovec *kiov) ... > > if (!regset || (kiov->iov_len % regset->size) != 0) > > return -EINVAL; So, to return again to 32-bit task I need sigreturn() again or add long-jump with 32-bit CS. I've disable that for 32-bit testing with (in compel_cure_remote): - if (ctl->addr_cmd) { + if (ctl->addr_cmd && user_regs_native(&ctl->orig.regs)) { And it works. It also works for native tasks, so why should we keep it? travis-ci: success for compel: kill self-unmap in parasite Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Andrei Vagin <avagin@virtuozzo.com> Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com> Acked-by: Andrei Vagin <avagin@virtuozzo.com> Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>
2016-11-25 15:51:00 +03:00
if (cmd == PARASITE_CMD_INIT_DAEMON)
return parasite_init_daemon(args);
return parasite_trap_cmd(cmd, args);
}