Adding upstream version 241.upstream/241upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 191 insertions, 0 deletions

diff --git a/src/nspawn/nspawn-stub-pid1.c b/src/nspawn/nspawn-stub-pid1.c
new file mode 100644
index 0000000..5d17df3
--- /dev/null
+++ b/src/nspawn/nspawn-stub-pid1.c
@@ -0,0 +1,191 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <sys/reboot.h>
+#include <sys/wait.h>
+#include <sys/prctl.h>
+#include <unistd.h>
+
+#include "def.h"
+#include "exit-status.h"
+#include "fd-util.h"
+#include "log.h"
+#include "missing.h"
+#include "nspawn-stub-pid1.h"
+#include "process-util.h"
+#include "signal-util.h"
+#include "time-util.h"
+
+static int reset_environ(const char *new_environment, size_t length) {
+        unsigned long start, end;
+
+        start = (unsigned long) new_environment;
+        end = start + length;
+
+        if (prctl(PR_SET_MM, PR_SET_MM_ENV_START, start, 0, 0) < 0)
+                return -errno;
+
+        if (prctl(PR_SET_MM, PR_SET_MM_ENV_END, end, 0, 0) < 0)
+                return -errno;
+
+        return 0;
+}
+
+int stub_pid1(sd_id128_t uuid) {
+        enum {
+                STATE_RUNNING,
+                STATE_REBOOT,
+                STATE_POWEROFF,
+        } state = STATE_RUNNING;
+
+        sigset_t fullmask, oldmask, waitmask;
+        usec_t quit_usec = USEC_INFINITY;
+        pid_t pid;
+        int r;
+
+        /* The new environment we set up, on the stack. */
+        char new_environment[] =
+                "container=systemd-nspawn\0"
+                "container_uuid=XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX";
+
+        /* Implements a stub PID 1, that reaps all processes and processes a couple of standard signals. This is useful
+         * for allowing arbitrary processes run in a container, and still have all zombies reaped. */
+
+        assert_se(sigfillset(&fullmask) >= 0);
+        assert_se(sigprocmask(SIG_BLOCK, &fullmask, &oldmask) >= 0);
+
+        pid = fork();
+        if (pid < 0)
+                return log_error_errno(errno, "Failed to fork child pid: %m");
+
+        if (pid == 0) {
+                /* Return in the child */
+                assert_se(sigprocmask(SIG_SETMASK, &oldmask, NULL) >= 0);
+                setsid();
+                return 0;
+        }
+
+        reset_all_signal_handlers();
+
+        log_close();
+        close_all_fds(NULL, 0);
+        log_open();
+
+        /* Flush out /proc/self/environ, so that we don't leak the environment from the host into the container. Also,
+         * set $container= and $container_uuid= so that clients in the container that query it from /proc/1/environ
+         * find them set. */
+        sd_id128_to_string(uuid, new_environment + sizeof(new_environment) - SD_ID128_STRING_MAX);
+        reset_environ(new_environment, sizeof(new_environment));
+
+        (void) rename_process("(sd-stubinit)");
+
+        assert_se(sigemptyset(&waitmask) >= 0);
+        assert_se(sigset_add_many(&waitmask,
+                                  SIGCHLD,          /* posix: process died */
+                                  SIGINT,           /* sysv: ctrl-alt-del */
+                                  SIGRTMIN+3,       /* systemd: halt */
+                                  SIGRTMIN+4,       /* systemd: poweroff */
+                                  SIGRTMIN+5,       /* systemd: reboot */
+                                  SIGRTMIN+6,       /* systemd: kexec */
+                                  SIGRTMIN+13,      /* systemd: halt */
+                                  SIGRTMIN+14,      /* systemd: poweroff */
+                                  SIGRTMIN+15,      /* systemd: reboot */
+                                  SIGRTMIN+16,      /* systemd: kexec */
+                                  -1) >= 0);
+
+        /* Note that we ignore SIGTERM (sysv's reexec), SIGHUP (reload), and all other signals here, since we don't
+         * support reexec/reloading in this stub process. */
+
+        for (;;) {
+                siginfo_t si;
+                usec_t current_usec;
+
+                si.si_pid = 0;
+                r = waitid(P_ALL, 0, &si, WEXITED|WNOHANG);
+                if (r < 0) {
+                        r = log_error_errno(errno, "Failed to reap children: %m");
+                        goto finish;
+                }
+
+                current_usec = now(CLOCK_MONOTONIC);
+
+                if (si.si_pid == pid || current_usec >= quit_usec) {
+
+                        /* The child we started ourselves died or we reached a timeout. */
+
+                        if (state == STATE_REBOOT) { /* dispatch a queued reboot */
+                                (void) reboot(RB_AUTOBOOT);
+                                r = log_error_errno(errno, "Failed to reboot: %m");
+                                goto finish;
+
+                        } else if (state == STATE_POWEROFF)
+                                (void) reboot(RB_POWER_OFF); /* if this fails, fall back to normal exit. */
+
+                        if (si.si_pid == pid && si.si_code == CLD_EXITED)
+                                r = si.si_status; /* pass on exit code */
+                        else
+                                r = EXIT_EXCEPTION; /* signal, coredump, timeout, … */
+
+                        goto finish;
+                }
+                if (si.si_pid != 0)
+                        /* We reaped something. Retry until there's nothing more to reap. */
+                        continue;
+
+                if (quit_usec == USEC_INFINITY)
+                        r = sigwaitinfo(&waitmask, &si);
+                else {
+                        struct timespec ts;
+                        r = sigtimedwait(&waitmask, &si, timespec_store(&ts, quit_usec - current_usec));
+                }
+                if (r < 0) {
+                        if (errno == EINTR) /* strace -p attach can result in EINTR, let's handle this nicely. */
+                                continue;
+                        if (errno == EAGAIN) /* timeout reached */
+                                continue;
+
+                        r = log_error_errno(errno, "Failed to wait for signal: %m");
+                        goto finish;
+                }
+
+                if (si.si_signo == SIGCHLD)
+                        continue; /* Let's reap this */
+
+                if (state != STATE_RUNNING)
+                        continue;
+
+                /* Would love to use a switch() statement here, but SIGRTMIN is actually a function call, not a
+                 * constant… */
+
+                if (si.si_signo == SIGRTMIN+3 ||
+                    si.si_signo == SIGRTMIN+4 ||
+                    si.si_signo == SIGRTMIN+13 ||
+                    si.si_signo == SIGRTMIN+14)
+
+                        state = STATE_POWEROFF;
+
+                else if (si.si_signo == SIGINT ||
+                         si.si_signo == SIGRTMIN+5 ||
+                         si.si_signo == SIGRTMIN+6 ||
+                         si.si_signo == SIGRTMIN+15 ||
+                         si.si_signo == SIGRTMIN+16)
+
+                        state = STATE_REBOOT;
+                else
+                        assert_not_reached("Got unexpected signal");
+
+                r = kill_and_sigcont(pid, SIGTERM);
+
+                /* Let's send a SIGHUP after the SIGTERM, as shells tend to ignore SIGTERM but do react to SIGHUP. We
+                 * do it strictly in this order, so that the SIGTERM is dispatched first, and SIGHUP second for those
+                 * processes which handle both. That's because services tend to bind configuration reload or something
+                 * else to SIGHUP. */
+
+                if (r != -ESRCH)
+                        (void) kill(pid, SIGHUP);
+
+                quit_usec = now(CLOCK_MONOTONIC) + DEFAULT_TIMEOUT_USEC;
+        }
+
+finish:
+        _exit(r < 0 ? EXIT_FAILURE : r);
+}