Add s6-notify-fd-from-socket and s6-notify-socket-from-fd

 Also add .gitkeep files, remove old include-local/s6lockd.h,
update a little bit of doc, make s6-ftrigrd pipe-only

1 files changed, 138 insertions, 0 deletions

diff --git a/src/supervision/s6-notify-socket-from-fd.c b/src/supervision/s6-notify-socket-from-fd.c
new file mode 100644
index 0000000..c443b40
--- /dev/null
+++ b/src/supervision/s6-notify-socket-from-fd.c
@@ -0,0 +1,138 @@
+/* ISC license. */
+
+#include <sys/types.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+
+#include <skalibs/uint64.h>
+#include <skalibs/types.h>
+#include <skalibs/bytestr.h>
+#include <skalibs/envexec.h>
+#include <skalibs/allreadwrite.h>
+#include <skalibs/tai.h>
+#include <skalibs/iopause.h>
+#include <skalibs/djbunix.h>
+#include <skalibs/socket.h>
+
+#define USAGE "s6-notify-socket-from-fd [ -d fd ] [ -f ] [ -t timeout ] [ -k ] prog..."
+#define dieusage() strerr_dieusage(100, USAGE)
+
+#define VAR "NOTIFY_SOCKET"
+
+enum golb_e
+{
+  GOLB_SINGLEFORK = 0x01,
+  GOLB_KEEP = 0x02,
+} ;
+
+enum gola_e
+{
+  GOLA_NOTIF,
+  GOLA_TIMEOUT,
+  GOLA_N
+} ;
+
+static inline int ipc_sendto (int fd, char const *s, size_t len, char const *path)
+{
+  struct sockaddr_un sa ;
+  size_t l = strlen(path) ;
+  if (l > IPCPATH_MAX) return (errno = ENAMETOOLONG, 0) ;
+  memset(&sa, 0, sizeof sa) ;
+  sa.sun_family = AF_UNIX ;
+  memcpy(sa.sun_path, path, l+1) ;
+  if (path[0] == '@') sa.sun_path[0] = 0 ;
+  return sendto(fd, s, len, MSG_NOSIGNAL, (struct sockaddr *)&sa, sizeof sa) >= 0 ;
+}
+
+static inline void notify_systemd (pid_t pid, char const *socketpath)
+{
+  size_t n = 16 ;
+  char fmt[16 + PID_FMT] = "READY=1\nMAINPID=" ;
+  int fd = ipc_datagram_b() ;
+  if (fd == -1) strerr_diefu1sys(111, "create socket") ;
+  n += pid_fmt(fmt + n, pid) ;
+  fmt[n++] = '\n' ;
+  if (!ipc_sendto(fd, fmt, n, socketpath))
+    strerr_diefu2sys(111, "send notification message to ", socketpath) ;
+  fd_close(fd) ;
+}
+
+static inline int run_child (int fd, unsigned int timeout, pid_t pid, char const *s)
+{
+  char dummy[4096] ;
+  iopause_fd x = { .fd = fd, .events = IOPAUSE_READ } ;
+  tain deadline = TAIN_INFINITE_RELATIVE ;
+  tain_now_g() ;
+  if (timeout) tain_from_millisecs(&deadline, timeout) ;
+  tain_add_g(&deadline, &deadline) ;
+  for (;;)
+  {
+    int r = iopause_g(&x, 1, &deadline) ;
+    if (r == -1) strerr_diefu1sys(111, "iopause") ;
+    if (!r) return 99 ;
+    r = sanitize_read(fd_read(fd, dummy, 4096)) ;
+    if (r < 0)
+      if (errno == EPIPE) return 1 ;
+      else strerr_diefu1sys(111, "read from parent") ;
+    else if (r && memchr(dummy, '\n', r)) break ;
+  }
+  fd_close(fd) ;
+  notify_systemd(pid, s) ;
+  return 0 ;
+}
+
+int main (int argc, char const *const *argv)
+{
+  static gol_bool const rgolb[] =
+  {
+    { .so = 0, .lo = "doublefork", .clear = GOLB_SINGLEFORK, .set = 0 },
+    { .so = 'f', .lo = "no-doublefork", .clear = 0, .set = GOLB_SINGLEFORK },
+    { .so = 'k', .lo = "keep-environment", .clear = 0, .set = GOLB_KEEP },
+  } ;
+  static gol_arg const rgola[] =
+  {
+    { .so = 'd', .lo = "notification-fd", .i = GOLA_NOTIF },
+    { .so = 't', .lo = "timeout", .i = GOLA_TIMEOUT },
+  } ;
+  char const *s = getenv(VAR) ;
+  unsigned int fd = 1 ;
+  unsigned int timeout = 0 ;
+  uint64_t wgolb = 0 ;
+  char const *wgola[GOLA_N] = { 0 } ;
+  unsigned int golc ;
+  PROG = "s6-notify-socket-from-fd" ;
+
+  golc = GOL_main(argc, argv, rgolb, rgola, &wgolb, wgola) ;
+  argc -= golc ; argv += golc ;
+  if (!argc) dieusage() ;
+
+  if (wgola[GOLA_NOTIF] && !uint0_scan(wgola[GOLA_NOTIF], &fd))
+    strerr_dief2x(100, "notification-fd", " must be an unsigned integer") ;
+  if (wgola[GOLA_TIMEOUT] && !uint0_scan(wgola[GOLA_TIMEOUT], &timeout))
+    strerr_dief2x(100, "timeout", " must be an unsigned integer") ;
+  
+  if (!s) xexec(argv) ;
+  else
+  {
+    pid_t parent = getpid() ;
+    pid_t child ;
+    int p[2] ;
+    if (pipe(p) == -1) strerr_diefu1sys(111, "pipe") ;
+    child = wgolb & GOLB_SINGLEFORK ? fork() : doublefork() ;
+    if (child == -1) strerr_diefu1sys(111, wgolb & GOLB_SINGLEFORK ? "fork" : "doublefork") ;
+    else if (!child)
+    {
+      PROG = "s6-notify-socket-from-fd (child)" ;
+      fd_close(p[1]) ;
+      return run_child(p[0], timeout, parent, s) ;
+    }
+    fd_close(p[0]) ;
+    if (fd_move(fd, p[1]) == -1) strerr_diefu1sys(111, "fd_move") ;
+    if (wgolb & GOLB_KEEP) xexec(argv) ;
+    else xmexec_n(argv, VAR, sizeof(VAR), 1) ;
+  }
+}