1 files changed, 68 insertions, 0 deletions
diff --git a/src/daemontools-extras/s6-fghack.c b/src/daemontools-extras/s6-fghack.c
new file mode 100644
index 0000000..1415706
--- /dev/null
+++ b/src/daemontools-extras/s6-fghack.c
@@ -0,0 +1,68 @@
+/* ISC license. */
+
+#include <sys/types.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/wait.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/allreadwrite.h>
+#include <skalibs/djbunix.h>
+
+#define USAGE "s6-fghack prog..."
+
+int main (int argc, char const *const *argv, char const *const *envp)
+{
+  int p[2] ;
+  int pcoe[2] ;
+  pid_t pid ;
+  char dummy ;
+  PROG = "s6-fghack" ;
+  if (argc < 2) strerr_dieusage(100, USAGE) ;
+  if (pipe(p) < 0) strerr_diefu1sys(111, "create hackpipe") ;
+  if (pipe(pcoe) < 0) strerr_diefu1sys(111, "create coepipe") ;
+
+  switch (pid = fork())
+  {
+    case -1 : strerr_diefu1sys(111, "fork") ;
+    case 0 :
+    {
+      int i = 0 ;
+      fd_close(p[0]) ;
+      fd_close(pcoe[0]) ;
+      if (coe(pcoe[1]) < 0) _exit(111) ;
+      for (; i < 30 ; i++) dup(p[1]) ; /* hack. gcc's warning is justified. */
+      pathexec_run(argv[1], argv+1, envp) ;
+      i = errno ;
+      if (fd_write(pcoe[1], "", 1) < 1) _exit(111) ;
+      _exit(i) ;
+    }
+  }
+
+  fd_close(p[1]) ;
+  fd_close(pcoe[1]) ;
+
+  switch (fd_read(pcoe[0], &dummy, 1))
+  {
+    case -1 : strerr_diefu1sys(111, "read on coepipe") ;
+    case 1 :
+    {
+      int wstat ;
+      if (wait_pid(pid, &wstat) < 0) strerr_diefu1sys(111, "wait_pid") ;
+      errno = WEXITSTATUS(wstat) ;
+      strerr_dieexec(111, argv[1]) ;
+    }
+  }
+
+  fd_close(pcoe[0]) ;
+
+  p[1] = fd_read(p[0], &dummy, 1) ;
+  if (p[1] < 0) strerr_diefu1sys(111, "read on hackpipe") ;
+  if (p[1]) strerr_dief2x(102, argv[1], " wrote on hackpipe") ;
+
+  {
+    int wstat ;
+    if (wait_pid(pid, &wstat) < 0) strerr_diefu1sys(111, "wait_pid") ;
+    if (WIFSIGNALED(wstat)) strerr_dief2x(111, argv[2], " crashed") ;
+    return WEXITSTATUS(wstat) ;
+  }
+}