* configure: new test for fcntl.

* stream.c (open_process): Fixed off-by one erroneous value of nargs,
causing memory leak of one string. Fixed memory leak on fork failure.
Fixed a deadlock that can occur in the pipe close function when
multiple pipes are in existence. This is fixed by setting the
FD_CLOEXEC flag on the pipe file descriptor. Without this, one child
process can hold another's pipe open, causing that other one not to
terminate when we're trying to shut it down, resulting in that child
blocked on a write, while we block on waitpid.

1 files changed, 11 insertions, 1 deletions

diff --git a/stream.c b/stream.c
index da58e38d..85c16d80 100644
--- a/stream.c
+++ b/stream.c
@@ -38,6 +38,9 @@
 #if HAVE_UNISTD_H
 #include <unistd.h>
 #endif
+#if HAVE_FCNTL_H
+#include <fcntl.h>
+#endif
 #include <float.h>
 #if HAVE_SYS_WAIT
 #include <sys/wait.h>
@@ -2131,7 +2134,7 @@ val open_process(val name, val mode_str, val args)
   int i, nargs;
 
   args = default_bool_arg(args);
-  nargs = c_num(length(args));
+  nargs = c_num(length(args)) + 1;
 
   if (pipe(fd) == -1) {
     uw_throwf(file_error_s, lit("opening pipe ~a, pipe syscall failed: ~a/~s"),
@@ -2151,6 +2154,9 @@ val open_process(val name, val mode_str, val args)
   pid = fork();
 
   if (pid == -1) {
+    for (i = 0; i < nargs; i++)
+      free(argv[i]);
+    free(argv);
     uw_throwf(file_error_s, lit("opening pipe ~a, fork syscall failed: ~a/~s"),
               name, num(errno), string_utf8(strerror(errno)), nao);
   } 
@@ -2187,6 +2193,10 @@ val open_process(val name, val mode_str, val args)
       free(argv[i]);
     free(argv);
 
+#if HAVE_FCNTL_H
+    fcntl(whichfd, F_SETFD, FD_CLOEXEC);
+#endif
+
     if ((f = fdopen(whichfd, utf8mode)) == 0) {
       int status;
       kill(pid, SIGINT);