- Added s6-uevent-listener and s6-uevent-spawner

 - s6-devd is now a wrapper around the former two
 - version: bump to 2.0.2.0, still missing s6-devd doc

5 files changed, 525 insertions, 241 deletions

diff --git a/src/minutils/deps-exe/s6-uevent-listener b/src/minutils/deps-exe/s6-uevent-listener
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/minutils/deps-exe/s6-uevent-listener
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/minutils/deps-exe/s6-uevent-spawner b/src/minutils/deps-exe/s6-uevent-spawner
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/minutils/deps-exe/s6-uevent-spawner
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/minutils/s6-devd.c b/src/minutils/s6-devd.c
index f51550c..9df5c80 100644
--- a/src/minutils/s6-devd.c
+++ b/src/minutils/s6-devd.c
@@ -1,281 +1,96 @@
 /* ISC license. */
 
-#ifndef _GNU_SOURCE
-#define _GNU_SOURCE
-#endif
-
-#include <sys/types.h>
-#include <unistd.h>
-#include <spawn.h>
-#include <signal.h>
-#include <sys/socket.h>
-#include <linux/netlink.h>
-#include <errno.h>
-#include <skalibs/allreadwrite.h>
-#include <skalibs/bytestr.h>
 #include <skalibs/uint.h>
 #include <skalibs/sgetopt.h>
 #include <skalibs/strerr2.h>
-#include <skalibs/tai.h>
-#include <skalibs/iopause.h>
-#include <skalibs/env.h>
 #include <skalibs/djbunix.h>
-#include <skalibs/sig.h>
-#include <skalibs/selfpipe.h>
+#include <s6-linux-utils/config.h>
 
-#define USAGE "s6-devd [ -q | -v ] [ -b kbufsz ] [ -t maxlife:maxterm:maxkill ] helperprogram..."
+#define USAGE "s6-devd [ -q | -v ] [ -b kbufsz ] [ -l linevar ] [ -t maxlife:maxterm:maxkill ] helperprogram..."
 #define dieusage() strerr_dieusage(100, USAGE)
 
-static unsigned int cont = 1, state = 0, verbosity = 1 ;
-static pid_t pid ;
-static tain_t lifetto = TAIN_INFINITE_RELATIVE,
-              termtto = TAIN_INFINITE_RELATIVE,
-              killtto = TAIN_INFINITE_RELATIVE,
-              deadline ;
-
-static inline int fd_recvmsg (int fd, struct msghdr *hdr)
-{
-  int r ;
-  do r = recvmsg(fd, hdr, 0) ;
-  while ((r == -1) && (errno == EINTR)) ;
-  return r ;
-}
-
-static inline int netlink_init (unsigned int kbufsz)
-{
-  struct sockaddr_nl nl = { .nl_family = AF_NETLINK, .nl_pad = 0, .nl_groups = 1, .nl_pid = 0 } ;
-  int fd = socket_internal(AF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT, DJBUNIX_FLAG_NB|DJBUNIX_FLAG_COE) ;
-  if (fd < 0) return -1 ;
-  if (bind(fd, (struct sockaddr *)&nl, sizeof(struct sockaddr_nl)) < 0) goto err ;
-  if (setsockopt(fd, SOL_SOCKET, SO_RCVBUFFORCE, &kbufsz, sizeof(unsigned int)) < 0) goto err ;
-  return fd ;
- err:
-  {
-    register int e = errno ;
-    fd_close(fd) ;
-    errno = e ;
-  }
-  return -1 ;
-}
-
-static inline void on_death (void)
-{
-  pid = 0 ;
-  state = 0 ;
-  tain_add_g(&deadline, &tain_infinite_relative) ;
-  if (cont == 2) cont = 0 ;
-}
-
-static inline void on_event (char const *const *argv, char const *const *envp, char const *s, unsigned int len)
-{
-  unsigned int envlen = env_len(envp) ;
-  unsigned int n = envlen + 1 + byte_count(s, len, '\0') ;
-  int e ;
-  char const *v[n] ;
-  if (!env_merge(v, n, envp, envlen, s, len))
-    strerr_diefu1sys(111, "env_merge") ;
-  e = posix_spawnp(&pid, argv[0], 0, 0, (char *const *)argv, (char * const *)v) ;
-  if (e) { errno = e ; strerr_diefu2sys(111, "spawn ", argv[0]) ; }
-  state = 1 ;
-  tain_add_g(&deadline, &lifetto) ;
-}
-
-static inline void handle_timeout (void)
+static inline int check_targ (char const *s)
 {
-  switch (state)
-  {
-    case 0 :
-      tain_add_g(&deadline, &tain_infinite_relative) ;
-      break ;
-    case 1 :
-      kill(pid, SIGTERM) ;
-      tain_add_g(&deadline, &termtto) ;
-      state++ ;
-      break ;
-    case 2 :
-      kill(pid, SIGKILL) ;
-      tain_add_g(&deadline, &killtto) ;
-      state++ ;
-      break ;
-    case 3 :
-      strerr_dief1x(99, "child resisted SIGKILL - check your kernel logs.") ;
-    default :
-      strerr_dief1x(101, "internal error: inconsistent state. Please submit a bug-report.") ;
-  }
-}
-
-static inline void handle_signals (void)
-{
-  for (;;)
-  {
-    char c = selfpipe_read() ;
-    switch (c)
-    {
-      case -1 : strerr_diefu1sys(111, "selfpipe_read") ;
-      case 0 : return ;
-      case SIGTERM :
-        cont = pid ? 2 : 0 ;
-        break ;
-      case SIGCHLD :
-        if (!pid) wait_reap() ;
-        else
-        {
-          int wstat ;
-          int r = wait_pid_nohang(pid, &wstat) ;
-          if (r < 0)
-            if (errno != ECHILD) strerr_diefu1sys(111, "wait_pid_nohang") ;
-            else break ;
-          else if (!r) break ;
-          on_death() ;
-        }
-        break ;
-      default :
-        strerr_dief1x(101, "internal error: inconsistent signal state. Please submit a bug-report.") ;
-    }
-  }
-}
-
-static inline void handle_netlink (int fd, char const *const *argv, char const *const *envp)
-{
-  char buf[4096] ;
-  int r ;
-  {
-    struct sockaddr_nl nl;
-    struct iovec iov = { .iov_base = &buf, .iov_len = sizeof(buf) } ;
-    char ctlmsg[CMSG_SPACE(sizeof(struct ucred))] ;
-    struct msghdr msg = {
-                          .msg_name = &nl,
-                          .msg_namelen = sizeof(struct sockaddr_nl),
-                          .msg_iov = &iov,
-                          .msg_iovlen = 1,
-                          .msg_control = ctlmsg,
-                          .msg_controllen = sizeof(ctlmsg),
-                          .msg_flags = 0
-                        } ;
-    r = sanitize_read(fd_recvmsg(fd, &msg)) ;
-    if (r < 0)
-    {
-      if (errno == EPIPE)
-      {
-        if (verbosity >= 2) strerr_warnw1x("received EOF on netlink") ;
-        cont = 0 ;
-        return ;
-      }
-      else strerr_diefu1sys(111, "receive netlink message") ;
-    }
-    if (!r) return ;
-    if (r < 32 || r > 4096)
-    {
-      if (verbosity >= 2)
-        strerr_warnw2x("received and ignored netlink message ", "with invalid length") ;
-      return ;
-    }
-    if (nl.nl_pid)
-    {
-      if (verbosity >= 3)
-      {
-        char fmt[UINT_FMT] ;
-        fmt[uint_fmt(fmt, nl.nl_pid)] = 0 ;
-        strerr_warnw3x("received and ignored netlink message ", "from userspace process ", fmt) ;
-      }
-      return ;
-    }
-  }
-  {
-    unsigned int start = str_len(buf) + 1 ;
-    if (start < 5 || start > (unsigned int)r)
-    {
-      if (verbosity >= 2)
-        strerr_warnw3x("received and ignored netlink message ", "with invalid header", " length") ;
-      return ;
-    }
-    if (str_strn(buf, start, "@/", 2) >= start)
-    {
-      if (verbosity >= 2)
-        strerr_warnw2x("received and ignored netlink message ", "with invalid header") ;
-      return ;
-    }
-    on_event(argv, envp, buf + start, r - start) ;
-  }
-}
-
-static inline int make_ttos (char const *s)
-{
-  unsigned int tlife = 0, tterm = 0, tkill = 0, pos = 0 ;
-  pos += uint_scan(s + pos, &tlife) ;
+  unsigned int t = 0, pos = 0 ;
+  pos += uint_scan(s + pos, &t) ;
   if (s[pos] && s[pos++] != ':') return 0 ;
-  if (!tlife) return 1 ;
-  tain_from_millisecs(&lifetto, tlife) ;
-  pos += uint_scan(s + pos, &tterm) ;
+  if (!t) return 1 ;
+  pos += uint_scan(s + pos, &t) ;
   if (s[pos] && s[pos++] != ':') return 0 ;
-  if (!tterm) return 1 ;
-  tain_from_millisecs(&termtto, tterm) ;
-  tain_add(&termtto, &termtto, &lifetto) ;
-  pos += uint_scan(s + pos, &tkill) ;
+  if (!t) return 1 ;
+  pos += uint_scan(s + pos, &t) ;
   if (s[pos]) return 0 ;
-  if (!tkill) return 1 ;
-  tain_from_millisecs(&killtto, tkill) ;
-  tain_add(&killtto, &killtto, &termtto) ;
   return 1 ;
 }
 
 int main (int argc, char const *const *argv, char const *const *envp)
 {
-  iopause_fd x[2] = { { -1, IOPAUSE_READ, 0 }, { -1, IOPAUSE_READ, 0 } } ;
+  unsigned int kbufsz = 65536, verbosity = 1 ;
+  char const *linevar = 0 ;
+  char const *targ = 0 ;
   PROG = "s6-devd" ;
   {
-    unsigned int kbufsz = 65536 ;
     subgetopt_t l = SUBGETOPT_ZERO ;
     for (;;)
     {
-      register int opt = subgetopt_r(argc, argv, "qvb:t:", &l) ;
+      register int opt = subgetopt_r(argc, argv, "qvb:l:t:", &l) ;
       if (opt == -1) break ;
       switch (opt)
       {
         case 'q' : if (verbosity) verbosity-- ; break ;
         case 'v' : verbosity++ ; break ;
         case 'b' : if (!uint0_scan(l.arg, &kbufsz)) dieusage() ; break ;
-        case 't' : if (!make_ttos(l.arg)) dieusage() ; break ;
+        case 'l' : linevar = l.arg ; break ;
+        case 't' : if (!check_targ(l.arg)) dieusage() ; targ = l.arg ; break ;
         default : dieusage() ;
       }
     }
     argc -= l.ind ; argv += l.ind ;
-    if (!argc) strerr_dieusage(100, USAGE) ;
-    close(0) ;
-    if (open_readb("/dev/null") < 0) strerr_diefu1sys(111, "open /dev/null for reading") ;
-    x[1].fd = netlink_init(kbufsz) ;
-    if (x[1].fd < 0) strerr_diefu1sys(111, "init netlink") ;
-  }
-
-  x[0].fd = selfpipe_init() ;
-  if (x[0].fd == -1) strerr_diefu1sys(111, "init selfpipe") ;
-  if (sig_ignore(SIGPIPE) < 0) strerr_diefu1sys(111, "ignore SIGPIPE") ;
-  {
-    sigset_t set ;
-    sigemptyset(&set) ;
-    sigaddset(&set, SIGTERM) ;
-    sigaddset(&set, SIGCHLD) ;
-    if (selfpipe_trapset(&set) < 0) strerr_diefu1sys(111, "trap signals") ;
   }
+  if (!argc) strerr_dieusage(100, USAGE) ;
 
-  tain_now_g() ;
-  tain_add_g(&deadline, &tain_infinite_relative) ;
-  if (verbosity >= 2) strerr_warni1x("starting") ;
-
-  while (cont)
   {
-    register int r = iopause_g(x, 1 + !pid, &deadline) ;
-    if (r < 0) strerr_diefu1sys(111, "iopause") ;
-    else if (!r) handle_timeout() ;
-    else
+    unsigned int m = 0, pos = 0 ;
+    char fmt[UINT_FMT * 3] ;
+    char const *newargv[argc + 15] ;
+    newargv[m++] = S6_LINUX_UTILS_BINPREFIX "s6-uevent-listener" ;
+    if (verbosity != 1)
+    {
+      newargv[m++] = "-v" ;
+      newargv[m++] = fmt + pos ;
+      pos += uint_fmt(fmt + pos, verbosity) ;
+      fmt[pos++] = 0 ;
+    }
+    if (kbufsz != 65536)
+    {
+      newargv[m++] = "-k" ;
+      newargv[m++] = fmt + pos ;
+      pos += uint_fmt(fmt + pos, kbufsz) ;
+      fmt[pos++] = 0 ;
+    }
+    newargv[m++] = "--" ;
+    newargv[m++] = S6_LINUX_UTILS_BINPREFIX "s6-uevent-spawner" ;
+    if (verbosity != 1)
+    {
+      newargv[m++] = "-v" ;
+      newargv[m++] = fmt + pos ;
+      pos += uint_fmt(fmt + pos, verbosity) ;
+      fmt[pos++] = 0 ;
+    }
+    if (linevar)
+    {
+      newargv[m++] = "-l" ;
+      newargv[m++] = linevar ;
+    }
+    if (targ)
     {
-      if ((x[0].revents | x[1].revents) & IOPAUSE_EXCEPT)
-        strerr_diefu1x(111, "iopause: trouble with pipes") ;
-      if (x[0].revents & IOPAUSE_READ) handle_signals() ;
-      else if (!pid && (x[1].revents & IOPAUSE_READ))
-        handle_netlink(x[1].fd, argv, envp) ;
+      newargv[m++] = "-t" ;
+      newargv[m++] = targ ;
     }
+    newargv[m++] = "--" ;
+    while (*argv) newargv[m++] = *argv++ ;
+    newargv[m++] = 0 ;
+    pathexec_run(newargv[0], newargv, envp) ;
+    strerr_dieexec(111, newargv[0]) ;
   }
-  if (verbosity >= 2) strerr_warni1x("exiting") ;
-  return 0 ;
 }
diff --git a/src/minutils/s6-uevent-listener.c b/src/minutils/s6-uevent-listener.c
new file mode 100644
index 0000000..b2cf455
--- /dev/null
+++ b/src/minutils/s6-uevent-listener.c
@@ -0,0 +1,233 @@
+/* ISC license. */
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#include <sys/types.h>
+#include <unistd.h>
+#include <errno.h>
+#include <signal.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
+#include <asm/types.h>
+#include <linux/netlink.h>
+#include <skalibs/allreadwrite.h>
+#include <skalibs/bytestr.h>
+#include <skalibs/uint.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/iopause.h>
+#include <skalibs/bufalloc.h>
+#include <skalibs/djbunix.h>
+#include <skalibs/sig.h>
+#include <skalibs/selfpipe.h>
+
+#define USAGE "s6-uevent-listener [ -v verbosity ] [ -b kbufsz ] helperprogram..."
+#define dieusage() strerr_dieusage(100, USAGE)
+#define dienomem() strerr_diefu1sys(111, "build string") ;
+
+static unsigned int cont = 1, verbosity = 1 ;
+static pid_t pid ;
+
+static inline int fd_recvmsg (int fd, struct msghdr *hdr)
+{
+  int r ;
+  do r = recvmsg(fd, hdr, MSG_DONTWAIT) ;
+  while ((r == -1) && (errno == EINTR)) ;
+  return r ;
+}
+
+static inline int netlink_init_stdin (unsigned int kbufsz)
+{
+  struct sockaddr_nl nl = { .nl_family = AF_NETLINK, .nl_pad = 0, .nl_groups = 0, .nl_pid = 0 } ;
+  close(0) ;
+  return socket_internal(AF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT, DJBUNIX_FLAG_NB|DJBUNIX_FLAG_COE) == 0
+   && bind(0, (struct sockaddr *)&nl, sizeof(struct sockaddr_nl)) == 0
+   && setsockopt(0, SOL_SOCKET, SO_RCVBUFFORCE, &kbufsz, sizeof(unsigned int)) == 0 ;
+}
+
+static inline void handle_signals (void)
+{
+  for (;;)
+  {
+    char c = selfpipe_read() ;
+    switch (c)
+    {
+      case -1 : strerr_diefu1sys(111, "selfpipe_read") ;
+      case 0 : return ;
+      case SIGTERM :
+        cont = 0 ;
+        fd_close(0) ;
+        break ;
+      case SIGCHLD :
+      {
+        char fmt[UINT_FMT] ;
+        int wstat ;
+        int r = wait_pid_nohang(pid, &wstat) ;
+        if (r < 0)
+          if (errno != ECHILD) strerr_diefu1sys(111, "wait_pid_nohang") ;
+          else break ;
+        else if (!r) break ;
+        if (WIFSIGNALED(wstat))
+        {
+          fmt[uint_fmt(fmt, WTERMSIG(wstat))] = 0 ;
+          strerr_dief2x(1, "child crashed with signal ", fmt) ;
+        }
+        else
+        {
+          fmt[uint_fmt(fmt, WEXITSTATUS(wstat))] = 0 ;
+          strerr_dief2x(1, "child exited ", fmt) ;
+        }
+      }
+      default :
+        strerr_dief1x(101, "internal error: inconsistent signal state. Please submit a bug-report.") ;
+    }
+  }
+}
+
+static void doit (char const *s, unsigned int len)
+{
+  if (!bufalloc_put(bufalloc_1, s, len)) dienomem() ;
+}
+
+static void terminate (void)
+{
+  if (!bufalloc_put(bufalloc_1, "", 1)) dienomem() ;
+}
+
+static inline void handle_netlink (void)
+{
+  char buf[8192] ;
+  static int inmulti = 0 ;
+  struct sockaddr_nl nl;
+  struct iovec iov = { .iov_base = &buf, .iov_len = sizeof(buf) } ;
+  struct msghdr msg =
+  {
+    .msg_name = &nl,
+    .msg_namelen = sizeof(struct sockaddr_nl),
+    .msg_iov = &iov,
+    .msg_iovlen = 1,
+    .msg_control = 0,
+    .msg_controllen = 0,
+    .msg_flags = 0
+  } ;
+  struct nlmsghdr *nlh = (struct nlmsghdr *)buf ;
+  int r = sanitize_read(fd_recvmsg(0, &msg)) ;
+  if (r < 0)
+  {
+    if (errno == EPIPE)
+    {
+      if (verbosity >= 2) strerr_warnw1x("received EOF on netlink") ;
+      cont = 0 ;
+      fd_close(0) ;
+      return ;
+    }
+    else strerr_diefu1sys(111, "receive netlink message") ;
+  }
+  if (!r) return ;
+  if (msg.msg_flags & MSG_TRUNC)
+    strerr_diefu2x(111, "buffer too small for ", "netlink message") ;
+  if (nl.nl_pid)
+  {
+    if (verbosity >= 3)
+    {
+      char fmt[UINT_FMT] ;
+      fmt[uint_fmt(fmt, nl.nl_pid)] = 0 ;
+      strerr_warnw3x("netlink message", " from userspace process ", fmt) ;
+    }
+    return ;
+  }
+
+  for (; NLMSG_OK(nlh, r) ; nlh = NLMSG_NEXT(nlh, r))
+    switch (nlh->nlmsg_type)
+    {
+      case NLMSG_NOOP : break ;
+      case NLMSG_ERROR :
+        if (verbosity >= 3)
+          strerr_warnw2x("spurious NLMSG_ERROR ", "netlink message") ;
+        break ;
+      case NLMSG_DONE :
+        if (inmulti)
+        {
+          inmulti = 0 ;
+          terminate() ;
+        }
+        else if (verbosity >= 3)
+          strerr_warnw2x("spurious NLMSG_DONE ", "netlink message") ;
+        break ;
+      default :
+        if (nlh->nlmsg_flags & NLM_F_MULTI) inmulti = 1 ;
+        else if (inmulti)
+        {
+          inmulti = 0 ;
+          terminate() ;
+          if (verbosity >= 3)
+            strerr_warnw2x("unterminated multipart ", "netlink message") ;
+        }
+        doit(NLMSG_DATA(nlh), (unsigned int)NLMSG_PAYLOAD(nlh, r)) ;
+        if (!inmulti) terminate() ;
+        break ;
+    }
+}
+
+int main (int argc, char const *const *argv, char const *const *envp)
+{
+  iopause_fd x[3] = { { .events = IOPAUSE_READ }, { .fd = 1 }, { .fd = 0, .events = IOPAUSE_READ } } ;
+  PROG = "s6-uevent-listener" ;
+  {
+    unsigned int kbufsz = 65536 ;
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "v:b:", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'v' : if (!uint0_scan(l.arg, &verbosity)) dieusage() ; break ;
+        case 'b' : if (!uint0_scan(l.arg, &kbufsz)) dieusage() ; break ;
+        default : dieusage() ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+    if (!argc) strerr_dieusage(100, USAGE) ;
+    if (!netlink_init_stdin(kbufsz)) strerr_diefu1sys(111, "init netlink") ;
+  }
+
+  x[0].fd = selfpipe_init() ;
+  if (x[0].fd < 0) strerr_diefu1sys(111, "init selfpipe") ;
+  if (sig_ignore(SIGPIPE) < 0) strerr_diefu1sys(111, "ignore SIGPIPE") ;
+  {
+    sigset_t set ;
+    sigemptyset(&set) ;
+    sigaddset(&set, SIGTERM) ;
+    sigaddset(&set, SIGCHLD) ;
+    if (selfpipe_trapset(&set) < 0) strerr_diefu1sys(111, "trap signals") ;
+  }
+
+  {
+    int fd ;
+    pid = child_spawn1_pipe(argv[0], argv, envp, &fd, 0) ;
+    if (!pid) strerr_diefu2sys(111, "spawn ", argv[0]) ;
+    if (fd_move(1, fd) < 0) strerr_diefu1sys(111, "move pipe to stdout") ;
+  }
+
+  if (verbosity >= 2) strerr_warni1x("starting") ;
+
+  while (cont || bufalloc_len(bufalloc_1))
+  {
+    register int r ;
+    x[1].events = bufalloc_len(bufalloc_1) ? IOPAUSE_WRITE : 0 ;
+    r = iopause(x, 2 + cont, 0, 0) ;
+    if (r < 0) strerr_diefu1sys(111, "iopause") ;
+    if (!r) continue ;
+    if (x[0].revents & IOPAUSE_EXCEPT)
+      strerr_diefu1x(111, "iopause: trouble with selfpipe") ;
+    if (x[0].revents & IOPAUSE_READ) handle_signals() ;
+    if (x[1].revents & IOPAUSE_WRITE)
+      if (!bufalloc_flush(bufalloc_1)) strerr_diefu1sys(111, "flush stdout") ;
+    if (cont && x[2].revents & IOPAUSE_READ) handle_netlink() ;
+  }
+  if (verbosity >= 2) strerr_warni1x("exiting") ;
+  return 0 ;
+}
diff --git a/src/minutils/s6-uevent-spawner.c b/src/minutils/s6-uevent-spawner.c
new file mode 100644
index 0000000..b074f1f
--- /dev/null
+++ b/src/minutils/s6-uevent-spawner.c
@@ -0,0 +1,234 @@
+/* ISC license. */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <spawn.h>
+#include <signal.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <skalibs/config.h>
+#include <skalibs/allreadwrite.h>
+#include <skalibs/buffer.h>
+#include <skalibs/bytestr.h>
+#include <skalibs/uint.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/tai.h>
+#include <skalibs/iopause.h>
+#include <skalibs/env.h>
+#include <skalibs/stralloc.h>
+#include <skalibs/djbunix.h>
+#include <skalibs/sig.h>
+#include <skalibs/selfpipe.h>
+#include <skalibs/skamisc.h>
+
+#define USAGE "s6-uevent-spawner [ -v verbosity ] [ -l linevar ] [ -t maxlife:maxterm:maxkill ] helperprogram..."
+#define dieusage() strerr_dieusage(100, USAGE)
+#define dienomem() strerr_diefu1sys(111, "build string") ;
+
+static unsigned int cont = 1, state = 0, verbosity = 1 ;
+static pid_t pid ;
+static tain_t lifetto = TAIN_INFINITE_RELATIVE,
+              termtto = TAIN_INFINITE_RELATIVE,
+              killtto = TAIN_INFINITE_RELATIVE,
+              deadline ;
+
+static inline void on_death (void)
+{
+  pid = 0 ;
+  state = 0 ;
+  tain_add_g(&deadline, &tain_infinite_relative) ;
+}
+
+static inline void on_event (char const *const *argv, char const *const *envp, char const *s, unsigned int len)
+{
+  posix_spawnattr_t attr ;
+  posix_spawn_file_actions_t actions ;
+  unsigned int envlen = env_len(envp) ;
+  unsigned int n = envlen + 1 + byte_count(s, len, '\0') ;
+  int e ;
+  char const *v[n] ;
+  if (!env_merge(v, n, envp, envlen, s, len))
+    strerr_diefu1sys(111, "env_merge") ;
+
+  e = posix_spawnattr_init(&attr) ;
+  if (e) { errno = e ; strerr_diefu1sys(111, "posix_spawnattr_init") ; }
+  {
+    sigset_t set ;
+    sigemptyset(&set) ;
+    e = posix_spawnattr_setsigmask(&attr, &set) ;
+    if (e) { errno = e ; strerr_diefu1sys(111, "posix_spawnattr_setsigmask") ; }
+    sigfillset(&set) ;
+    e = posix_spawnattr_setsigdefault(&attr, &set) ;
+    if (e) { errno = e ; strerr_diefu1sys(111, "posix_spawnattr_setsigdefault") ; }
+  }
+  e = posix_spawn_file_actions_init(&actions) ;
+  if (e) { errno = e ; strerr_diefu1sys(111, "posix_spawn_file_actions_init") ; }
+  e = posix_spawn_file_actions_addopen(&actions, 0, "/dev/null", O_RDONLY, S_IRUSR) ;
+  if (e) { errno = e ; strerr_diefu1sys(111, "posix_spawn_file_actions_addopen") ; }
+  e = posix_spawnp(&pid, argv[0], &actions, &attr, (char *const *)argv, (char * const *)v) ;
+  if (e) { errno = e ; strerr_diefu2sys(111, "spawn ", argv[0]) ; }
+  posix_spawn_file_actions_destroy(&actions) ;
+  posix_spawnattr_destroy(&attr) ;
+  state = 1 ;
+  tain_add_g(&deadline, &lifetto) ;
+}
+
+static inline void handle_timeout (void)
+{
+  switch (state)
+  {
+    case 0 :
+      tain_add_g(&deadline, &tain_infinite_relative) ;
+      break ;
+    case 1 :
+      kill(pid, SIGTERM) ;
+      tain_add_g(&deadline, &termtto) ;
+      state++ ;
+      break ;
+    case 2 :
+      kill(pid, SIGKILL) ;
+      tain_add_g(&deadline, &killtto) ;
+      state++ ;
+      break ;
+    case 3 :
+      strerr_dief1x(99, "child resisted SIGKILL - check your kernel logs.") ;
+    default :
+      strerr_dief1x(101, "internal error: inconsistent state. Please submit a bug-report.") ;
+  }
+}
+
+static inline void handle_signals (void)
+{
+  for (;;)
+  {
+    char c = selfpipe_read() ;
+    switch (c)
+    {
+      case -1 : strerr_diefu1sys(111, "selfpipe_read") ;
+      case 0 : return ;
+      case SIGCHLD :
+        if (!pid) wait_reap() ;
+        else
+        {
+          int wstat ;
+          int r = wait_pid_nohang(pid, &wstat) ;
+          if (r < 0)
+            if (errno != ECHILD) strerr_diefu1sys(111, "wait_pid_nohang") ;
+            else break ;
+          else if (!r) break ;
+          on_death() ;
+        }
+        break ;
+      default :
+        strerr_dief1x(101, "internal error: inconsistent signal handling. Please submit a bug-report.") ;
+    }
+  }
+}
+
+static inline void handle_stdin (stralloc *sa, char const *linevar, char const *const *argv, char const *const *envp)
+{
+  for (;;)
+  {
+    unsigned int start ;
+    register int r ;
+    if (!sa->len && linevar)
+      if (!stralloc_cats(sa, linevar) || !stralloc_catb(sa, "=", 1))
+        dienomem() ;
+    start = sa->len ;
+    r = sanitize_read(skagetln(buffer_0, sa, 0)) ;
+    if (r < 0)
+    {
+      cont = 0 ;
+      if (errno != EPIPE && verbosity) strerr_warnwu1sys("read from stdin") ;
+    }
+    if (r <= 0) break ;
+    if (sa->len == start + 1)
+    {
+      start = linevar ? 0 : str_len(sa->s) + 1 ;
+      if (start >= sa->len)
+      {
+        if (verbosity) strerr_warnw1x("empty event!") ;
+      }
+      else on_event(argv, envp, sa->s + start, sa->len - 1 - start) ;
+      sa->len = 0 ;
+    }
+  }
+}
+
+static inline int make_ttos (char const *s)
+{
+  unsigned int tlife = 0, tterm = 0, tkill = 0, pos = 0 ;
+  pos += uint_scan(s + pos, &tlife) ;
+  if (s[pos] && s[pos++] != ':') return 0 ;
+  if (!tlife) return 1 ;
+  tain_from_millisecs(&lifetto, tlife) ;
+  pos += uint_scan(s + pos, &tterm) ;
+  if (s[pos] && s[pos++] != ':') return 0 ;
+  if (!tterm) return 1 ;
+  tain_from_millisecs(&termtto, tterm) ;
+  tain_add(&termtto, &termtto, &lifetto) ;
+  pos += uint_scan(s + pos, &tkill) ;
+  if (s[pos]) return 0 ;
+  if (!tkill) return 1 ;
+  tain_from_millisecs(&killtto, tkill) ;
+  tain_add(&killtto, &killtto, &termtto) ;
+  return 1 ;
+}
+
+int main (int argc, char const *const *argv, char const *const *envp)
+{
+  iopause_fd x[2] = { { .events = IOPAUSE_READ }, { .fd = 0, .events = IOPAUSE_READ } } ;
+  char const *linevar = 0 ;
+  stralloc sa = STRALLOC_ZERO ;
+  PROG = "s6-uevent-spawner" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "l:v:t:", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'l' : linevar = optarg ; break ;
+        case 'v' : if (!uint0_scan(l.arg, &verbosity)) dieusage() ; break ;
+        case 't' : if (!make_ttos(l.arg)) dieusage() ; break ;
+        default : dieusage() ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+    if (!argc) strerr_dieusage(100, USAGE) ;
+  }
+  if (linevar && linevar[str_chr(linevar, '=')])
+    strerr_dief2x(100, "invalid variable: ", linevar) ;
+
+  x[0].fd = selfpipe_init() ;
+  if (x[0].fd == -1) strerr_diefu1sys(111, "init selfpipe") ;
+  if (sig_ignore(SIGPIPE) < 0) strerr_diefu1sys(111, "ignore SIGPIPE") ;
+  if (selfpipe_trap(SIGCHLD) < 0) strerr_diefu1sys(111, "trap SIGCHLD") ;
+  if (setenv("PATH", SKALIBS_DEFAULTPATH, 0) < 0)
+    strerr_diefu1sys(111, "setenv PATH") ;
+
+  tain_now_g() ;
+  tain_add_g(&deadline, &tain_infinite_relative) ;
+  if (verbosity >= 2) strerr_warni1x("starting") ;
+
+  while (cont || pid)
+  {
+    register int r = iopause_g(x, 1 + (!pid && cont), &deadline) ;
+    if (r < 0) strerr_diefu1sys(111, "iopause") ;
+    else if (!r) handle_timeout() ;
+    else
+    {
+      if (x[0].revents & IOPAUSE_EXCEPT)
+        strerr_diefu1x(111, "iopause: trouble with selfpipe") ;
+      if (x[0].revents & IOPAUSE_READ) handle_signals() ;
+      else if (!pid && cont && (x[1].revents & IOPAUSE_READ))
+        handle_stdin(&sa, linevar, argv, envp) ;
+    }
+  }
+  if (verbosity >= 2) strerr_warni1x("exiting") ;
+  return 0 ;
+}