1 files changed, 309 insertions, 0 deletions
diff --git a/src/shutdown/s6-linux-init-shutdownd.c b/src/shutdown/s6-linux-init-shutdownd.c
new file mode 100644
index 0000000..7f86e66
--- /dev/null
+++ b/src/shutdown/s6-linux-init-shutdownd.c
@@ -0,0 +1,309 @@
+/* ISC license. */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <string.h>
+#include <errno.h>
+#include <signal.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <sys/wait.h>
+
+#include <skalibs/posixplz.h>
+#include <skalibs/uint32.h>
+#include <skalibs/types.h>
+#include <skalibs/allreadwrite.h>
+#include <skalibs/bytestr.h>
+#include <skalibs/buffer.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/sig.h>
+#include <skalibs/tai.h>
+#include <skalibs/direntry.h>
+#include <skalibs/djbunix.h>
+#include <skalibs/iopause.h>
+#include <skalibs/skamisc.h>
+
+#include <execline/config.h>
+
+#include <s6/s6-supervise.h>
+
+#include <s6-linux-init/config.h>
+#include "defaults.h"
+#include "initctl.h"
+#include "hpr.h"
+
+#define STAGE4_FILE "stage 4"
+#define SCANPREFIX S6_LINUX_INIT_TMPFS "/" SCANDIR "/"
+#define SCANPREFIXLEN (sizeof(SCANPREFIX) - 1)
+#define DOTPREFIX ".s6-linux-init-shutdownd:"
+#define DOTPREFIXLEN (sizeof(DOTPREFIX) - 1)
+#define DOTSUFFIX ":XXXXXX"
+#define DOTSUFFIXLEN (sizeof(DOTSUFFIX) - 1)
+
+#define USAGE "s6-linux-init-shutdownd [ -c basedir ] [ -g gracetime ]"
+#define dieusage() strerr_dieusage(100, USAGE)
+
+static char const *basedir = BASEDIR ;
+
+struct at_s
+{
+  int fd ;
+  char const *name ;
+} ;
+
+static int renametemp (char const *s, mode_t mode, void *data)
+{
+  struct at_s *at = data ;
+  (void)mode ;
+  return renameat(at->fd, at->name, at->fd, s) ;
+}
+
+static int mkrenametemp (int fd, char const *src, char *dst)
+{
+  struct at_s at = { .fd = fd, .name = src } ;
+  return mkfiletemp(dst, &renametemp, 0700, &at) ;
+}
+
+static inline void run_stage3 (char const *basedir, char const *const *envp)
+{
+  pid_t pid ;
+  size_t basedirlen = strlen(basedir) ;
+  char stage3[basedirlen + sizeof("/scripts/" STAGE3)] ;
+  char const *stage3_argv[2] = { stage3, 0 } ;
+  memcpy(stage3, basedir, basedirlen) ;
+  memcpy(stage3 + basedirlen, "/scripts/" STAGE3, sizeof("/scripts/" STAGE3)) ;
+  pid = child_spawn0(stage3_argv[0], stage3_argv, envp) ;
+  if (pid)
+  {
+    int wstat ;
+    if (wait_pid(pid, &wstat) == -1) strerr_diefu1sys(111, "waitpid") ;
+    if (WIFSIGNALED(wstat))
+    {
+      char fmt[UINT_FMT] ;
+      fmt[uint_fmt(fmt, WTERMSIG(wstat))] = 0 ;
+      strerr_warnw3x(stage3, " was killed by signal ", fmt) ;
+    }
+    else if (WEXITSTATUS(wstat))
+    {
+      char fmt[UINT_FMT] ;
+      fmt[uint_fmt(fmt, WTERMSIG(wstat))] = 0 ;
+      strerr_warnw3x(stage3, " was killed by signal ", fmt) ;
+    }
+    else if (WEXITSTATUS(wstat))
+    {
+      char fmt[UINT_FMT] ;
+      fmt[uint_fmt(fmt, WEXITSTATUS(wstat))] = 0 ;
+      strerr_warnw3x(stage3, " exited ", fmt) ;
+    }
+  }
+  else strerr_warnwu2sys("spawn ", stage3) ;
+}
+
+static inline void prepare_shutdown (buffer *b, tain_t *deadline, unsigned int *grace_time)
+{
+  uint32_t u ;
+  char pack[TAIN_PACK + 4] ;
+  ssize_t r = sanitize_read(buffer_get(b, pack, TAIN_PACK + 4)) ;
+  if (r == -1) strerr_diefu1sys(111, "read from pipe") ;
+  if (r < TAIN_PACK + 4) strerr_dief1x(101, "bad shutdown protocol") ;
+  tain_unpack(pack, deadline) ;
+  uint32_unpack_big(pack + TAIN_PACK, &u) ;
+  if (u && u <= 300000) *grace_time = u ;
+}
+
+static inline void handle_fifo (buffer *b, char *what, tain_t *deadline, unsigned int *grace_time)
+{
+  for (;;)
+  {
+    char c ;
+    ssize_t r = sanitize_read(buffer_get(b, &c, 1)) ;
+    if (r == -1) strerr_diefu1sys(111, "read from pipe") ;
+    else if (!r) break ;
+    switch (c)
+    {
+      case 'S' :
+      case 'h' :
+      case 'p' :
+      case 'r' :
+        *what = c ;
+        prepare_shutdown(b, deadline, grace_time) ;
+        break ;
+      case 'c' :
+        *what = 'S' ;
+        tain_add_g(deadline, &tain_infinite_relative) ;
+        break ;
+      default :
+      {
+        char s[2] = { c, 0 } ;
+        strerr_warnw2x("unknown command: ", s) ;
+      }
+      break ;
+    }
+  }
+}
+
+static inline void prepare_stage4 (char const *basedir, char what)
+{
+  buffer b ;
+  int fd ;
+  char buf[512] ;
+  unlink_void(STAGE4_FILE ".new") ;
+  fd = open_excl(STAGE4_FILE ".new") ;
+  if (fd == -1) strerr_diefu3sys(111, "open ", STAGE4_FILE ".new", " for writing") ;
+  buffer_init(&b, &buffer_write, fd, buf, 512) ;
+
+  if (buffer_puts(&b,
+    "#!" EXECLINE_SHEBANGPREFIX "execlineb -P\n\n"
+    EXECLINE_EXTBINPREFIX "foreground { "
+    S6_LINUX_INIT_BINPREFIX "s6-linux-init-umountall }\n"
+    S6_LINUX_INIT_BINPREFIX "s6-linux-init-hpr -f -") < 0
+   || buffer_put(&b, &what, 1) < 0
+   || buffer_putsflush(&b, "\n") < 0)
+    strerr_diefu2sys(111, "write to ", STAGE4_FILE ".new") ;
+  if (fchmod(fd, S_IRWXU) == -1)
+    strerr_diefu2sys(111, "fchmod ", STAGE4_FILE ".new") ;
+  fd_close(fd) ;
+  if (rename(STAGE4_FILE ".new", STAGE4_FILE) == -1)
+    strerr_diefu4sys(111, "rename ", STAGE4_FILE ".new", " to ", STAGE4_FILE) ;
+}
+
+static inline void unsupervise_tree (void)
+{
+  static char const *except[] =
+  {
+    LOGGER_SERVICEDIR,
+    SHUTDOWND_SERVICEDIR,
+ /* EARLYGETTY_SERVICEDIR, */
+    0
+  } ;
+  DIR *dir = opendir(S6_LINUX_INIT_TMPFS "/" SCANDIR) ;
+  int fdd ;
+  if (!dir)
+    strerr_diefu1sys(111, "opendir " S6_LINUX_INIT_TMPFS "/" SCANDIR) ;
+  fdd = dirfd(dir) ;
+  if (fdd == -1)
+    strerr_diefu1sys(111, "dir_fd " S6_LINUX_INIT_TMPFS "/" SCANDIR) ;
+  for (;;)
+  {
+    char const *const *p = except ;
+    direntry *d ;
+    errno = 0 ;
+    d = readdir(dir) ;
+    if (!d) break ;
+    if (d->d_name[0] == '.') continue ;
+    for (; *p ; p++) if (!strcmp(*p, d->d_name)) break ;
+    if (!*p)
+    {
+      size_t dlen = strlen(d->d_name) ;
+      char fn[SCANPREFIXLEN + DOTPREFIXLEN + dlen + DOTSUFFIXLEN + 1] ;
+      memcpy(fn, SCANPREFIX DOTPREFIX, SCANPREFIXLEN + DOTPREFIXLEN) ;
+      memcpy(fn + SCANPREFIXLEN + DOTPREFIXLEN, d->d_name, dlen) ;
+      memcpy(fn + SCANPREFIXLEN + DOTPREFIXLEN + dlen, DOTSUFFIX, DOTSUFFIXLEN + 1) ;
+      if (mkrenametemp(fdd, d->d_name, fn + SCANPREFIXLEN) == -1)
+      {
+        strerr_warnwu4sys("rename " SCANPREFIX, d->d_name, " to something based on ", fn) ;
+        unlinkat(fdd, d->d_name, 0) ;
+        /* if it still fails, too bad, it will restart in stage 4 and race */
+      }
+      else
+        s6_svc_writectl(fn, S6_SUPERVISE_CTLDIR, "dx", 2) ;
+    }
+  }
+  if (errno)
+    strerr_diefu1sys(111, "readdir " S6_LINUX_INIT_TMPFS "/" SCANDIR) ;
+  dir_close(dir) ;
+}
+
+int main (int argc, char const *const *argv, char const *const *envp)
+{
+  char what = 'S' ;
+  unsigned int grace_time = 3000 ;
+  tain_t deadline ;
+  int fdr, fdw ;
+  buffer b ;
+  char buf[64] ;
+  PROG = "s6-linux-init-shutdownd" ;
+
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      int opt = subgetopt_r(argc, argv, "c:g:", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'c' : basedir = l.arg ; break ;
+        case 'g' : if (!uint0_scan(l.arg, &grace_time)) dieusage() ; break ;
+        default : dieusage() ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+  if (basedir[0] != '/')
+    strerr_dief2x(100, "basedir", " must be an absolute path") ;
+  if (grace_time > 300000) grace_time = 300000 ;
+
+ /* if we're in stage 4, exec it immediately */
+  {
+    char const *stage4_argv[2] = { "./" STAGE4_FILE, 0 } ;
+    execve(stage4_argv[0], (char **)stage4_argv, (char *const *)envp) ;
+    if (errno != ENOENT)
+      strerr_warnwu2sys("exec ", stage4_argv[0]) ;
+  }
+
+  fdr = open_read(SHUTDOWND_FIFO) ;
+  if (fdr == -1 || coe(fdr) == -1)
+    strerr_diefu3sys(111, "open ", SHUTDOWND_FIFO, " for reading") ;
+  fdw = open_write(SHUTDOWND_FIFO) ;
+  if (fdw == -1 || coe(fdw) == -1)
+    strerr_diefu3sys(111, "open ", SHUTDOWND_FIFO, " for writing") ;
+  if (sig_ignore(SIGPIPE) == -1)
+    strerr_diefu1sys(111, "sig_ignore SIGPIPE") ;
+  buffer_init(&b, &buffer_read, fdr, buf, 64) ;
+  tain_now_g() ;
+  tain_add_g(&deadline, &tain_infinite_relative) ;
+
+  for (;;)
+  {
+    iopause_fd x = { .fd = fdr, .events = IOPAUSE_READ } ;
+    int r = iopause_g(&x, 1, &deadline) ;
+    if (r == -1) strerr_diefu1sys(111, "iopause") ;
+    if (!r)
+    {
+      run_stage3(basedir, envp) ;
+      tain_now_g() ;
+      if (what != 'S') break ;
+      tain_add_g(&deadline, &tain_infinite_relative) ;
+      continue ;
+    }
+    if (x.revents & IOPAUSE_READ)
+      handle_fifo(&b, &what, &deadline, &grace_time) ;
+  }
+
+  fd_close(fdw) ;
+  fd_close(fdr) ;
+  fd_close(1) ;
+  if (open("/dev/console", O_WRONLY) != 1)
+    strerr_diefu1sys(111, "open /dev/console for writing") ;
+  if (fd_copy(2, 1) == -1) strerr_warnwu1sys("fd_copy") ;
+
+
+ /* The end is coming! */
+
+  prepare_stage4(basedir, what) ;
+  unsupervise_tree() ;
+  sync() ;
+  if (sig_ignore(SIGTERM) == -1) strerr_warnwu1sys("sig_ignore SIGTERM") ;
+  strerr_warni1x("sending all processes the TERM signal...") ;
+  kill(-1, SIGTERM) ;
+  kill(-1, SIGCONT) ;
+  tain_from_millisecs(&deadline, grace_time) ;
+  tain_add_g(&deadline, &deadline) ;
+  deepsleepuntil_g(&deadline) ;
+  sync() ;
+  strerr_warni1x("sending all processes the KILL signal...") ;
+  kill(-1, SIGKILL) ;
+  return 0 ;
+}