From 3b51a07e478d64a84e40b3a7c026b2f8566b194b Mon Sep 17 00:00:00 2001
From: Rob Landley <rob@landley.net>
Date: Sun, 27 Sep 2015 09:03:41 -0500
Subject: Another chunk of nommu support, replacing toys.recursion with
 toys.stacktop.

---
 lib/lib.h   |  7 ++++---
 lib/xwrap.c | 18 +++++++++++++-----
 2 files changed, 17 insertions(+), 8 deletions(-)

(limited to 'lib')

diff --git a/lib/lib.h b/lib/lib.h
index cbac3aa5..d76dcc0c 100644
--- a/lib/lib.h
+++ b/lib/lib.h
@@ -98,6 +98,7 @@ void xputc(char c);
 void xflush(void);
 void xexec(char **argv);
 pid_t xpopen_both(char **argv, int *pipes);
+int xwaitpid(pid_t pid);
 int xpclose_both(pid_t pid, int *pipes);
 pid_t xpopen(char **argv, int *pipe, int stdout);
 pid_t xpclose(pid_t pid, int pipe);
@@ -248,12 +249,12 @@ void names_to_pid(char **names, int (*callback)(pid_t pid, char *name));
 
 // Returning from a function can modify a potentially shared stack,
 // so this has to always inline.
-
 static inline pid_t xvfork(void)
 {
-  pid_t p = vfork();
+  pid_t p;
 
-  if (p == -1) perror_exit("vfork");
+  toys.stacktop = 0;
+  if ((p = vfork()) == -1) perror_exit("vfork");
 
   return p;
 }
diff --git a/lib/xwrap.c b/lib/xwrap.c
index 80862828..e5dc4826 100644
--- a/lib/xwrap.c
+++ b/lib/xwrap.c
@@ -133,7 +133,8 @@ void xflush(void)
 // with a path isn't a builtin, so /bin/sh won't match the builtin sh.
 void xexec(char **argv)
 {
-  if (CFG_TOYBOX && !CFG_TOYBOX_NORECURSE) toy_exec(argv);
+  // Only recurse to builtin when we have multiplexer and !vfork context.
+  if (CFG_TOYBOX && !CFG_TOYBOX_NORECURSE && toys.stacktop) toy_exec(argv);
   execvp(argv[0], argv);
 
   perror_msg("exec %s", argv[0]);
@@ -198,17 +199,24 @@ pid_t xpopen_both(char **argv, int *pipes)
   return pid;
 }
 
-int xpclose_both(pid_t pid, int *pipes)
+// Wait for child process to exit, then return adjusted exit code.
+int xwaitpid(pid_t pid)
 {
-  int rc = 127;
+  int status;
+
+  while (-1 == waitpid(pid, &status, 0) && errno == EINTR);
+
+  return WIFEXITED(status) ? WEXITSTATUS(status) : WTERMSIG(status)+127;
+}
 
+int xpclose_both(pid_t pid, int *pipes)
+{
   if (pipes) {
     close(pipes[0]);
     close(pipes[1]);
   }
-  waitpid(pid, &rc, 0);
 
-  return WIFEXITED(rc) ? WEXITSTATUS(rc) : WTERMSIG(rc) + 127;
+  return xwaitpid(pid);
 }
 
 // Wrapper to xpopen with a pipe for just one of stdin/stdout
-- 
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