Add internal API task_reparent(), used in posix_spawn(). Move libc/spawn/lib_ps.c to sched/task_posixspawn.c; Move libc/spawn/spawn.h to include/nuttx/spawn.h

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5531 42af7a65-404d-4744-a932-0658087f49c3

3 files changed, 62 insertions, 29 deletions

diff --git a/apps/builtin/exec_builtin.c b/apps/builtin/exec_builtin.c
index 803d1ef34..60e8b742d 100644
--- a/apps/builtin/exec_builtin.c
+++ b/apps/builtin/exec_builtin.c
@@ -124,7 +124,7 @@ static void bultin_semtake(FAR sem_t *sem)
   do
     {
       ret = sem_wait(sem);
-      ASSERT(ret == 0 || errno == EINTR);
+      ASSERT(ret == 0 || get_errno() == EINTR);
     }
   while (ret != 0);
 }
@@ -152,7 +152,7 @@ static int builtin_taskcreate(int index, FAR const char **argv)
 
   if (b == NULL)
     { 
-      errno = ENOENT;
+      set_errno(ENOENT);
       return ERROR;
     }
 
@@ -228,7 +228,7 @@ static int builtin_proxy(int argc, char *argv[])
     {
       /* Remember the errno value.  ret is already set to ERROR */
 
-      g_builtin_parms.errcode = errno;
+      g_builtin_parms.errcode = get_errno();
       sdbg("ERROR: open of %s failed: %d\n",
            g_builtin_parms.redirfile, g_builtin_parms.errcode);
     }
@@ -246,7 +246,7 @@ static int builtin_proxy(int argc, char *argv[])
       ret = dup2(fd, 1);
       if (ret < 0)
         {
-          g_builtin_parms.errcode = errno;
+          g_builtin_parms.errcode = get_errno();
           sdbg("ERROR: dup2 failed: %d\n", g_builtin_parms.errcode);
         }
 
@@ -266,12 +266,18 @@ static int builtin_proxy(int argc, char *argv[])
       ret = builtin_taskcreate(g_builtin_parms.index, g_builtin_parms.argv);
       if (ret < 0)
         {
-          g_builtin_parms.errcode = errno;
+          g_builtin_parms.errcode = get_errno();
           sdbg("ERROR: builtin_taskcreate failed: %d\n",
                g_builtin_parms.errcode);
         }
     }
 
+  /* NOTE:  There is a logical error here if CONFIG_SCHED_HAVE_PARENT is
+   * defined:  The new task is the child of this proxy task, not the
+   * original caller.  As a consequence, operations like waitpid() will
+   * fail on the caller's thread.
+   */
+
   /* Post the semaphore to inform the parent task that we have completed
    * what we need to do.
    */
@@ -340,11 +346,21 @@ static inline int builtin_startproxy(int index, FAR const char **argv,
   ret = sched_getparam(0, &param);
   if (ret < 0)
     {
-      errcode = errno;
+      errcode = get_errno();
       sdbg("ERROR: sched_getparam failed: %d\n", errcode);
-      goto errout;
+      goto errout_with_sem;
     }
 
+  /* Disable pre-emption so that the proxy does not run until we waitpid
+   * is called.  This is probably unnecessary since the builtin_proxy has
+   * the same priority as this thread; it should be schedule behind this
+   * task in the ready-to-run list.
+   */
+
+#ifdef CONFIG_SCHED_WAITPID
+  sched_lock();
+#endif
+
   /* Start the intermediary/proxy task at the same priority as the parent task. */
 
   proxy = TASK_CREATE("builtin_proxy", param.sched_priority,
@@ -352,9 +368,9 @@ static inline int builtin_startproxy(int index, FAR const char **argv,
                       (FAR const char **)NULL);
   if (proxy < 0)
     {
-      errcode = errno;
+      errcode = get_errno();
       sdbg("ERROR: Failed to start builtin_proxy: %d\n", errcode);
-      goto errout;
+      goto errout_with_lock;
     }
 
    /* Wait for the proxy to complete its job.  We could use waitpid()
@@ -365,7 +381,8 @@ static inline int builtin_startproxy(int index, FAR const char **argv,
    ret = waitpid(proxy, &status, 0);
    if (ret < 0)
      {
-      sdbg("ERROR: waitpid() failed: %d\n", errno);
+       sdbg("ERROR: waitpid() failed: %d\n", get_errno());
+       goto errout_with_lock;
      }
 #else
    bultin_semtake(&g_builtin_execsem);
@@ -377,7 +394,12 @@ static inline int builtin_startproxy(int index, FAR const char **argv,
    builtin_semgive(&g_builtin_parmsem);
    return g_builtin_parms.result;
 
-errout:
+errout_with_lock:
+#ifdef CONFIG_SCHED_WAITPID
+  sched_unlock();
+#endif
+
+errout_with_sem:
   set_errno(errcode);
   builtin_semgive(&g_builtin_parmsem);
   return ERROR;
diff --git a/apps/nshlib/nsh_builtin.c b/apps/nshlib/nsh_builtin.c
index 343a0824b..0d5a0231c 100644
--- a/apps/nshlib/nsh_builtin.c
+++ b/apps/nshlib/nsh_builtin.c
@@ -131,12 +131,14 @@ int nsh_builtin(FAR struct nsh_vtbl_s *vtbl, FAR const char *cmd,
     {
       /* The application was successfully started with pre-emption disabled.
        * In the simplest cases, the application will not have run because the
-       * the scheduler is locked.  but in the case were I/O redirected, a 
-       * proxy task ran and, as result, so may have the application.
+       * the scheduler is locked.  But in the case where I/O was redirected, a 
+       * proxy task ran and broke our lock.  As result, the application may
+       * have aso ran if its priority was higher than than the priority of
+       * this thread.
        *
-       * If the application did not run and if the application was not
-       * backgrounded, then we need to wait here for the application to
-       * exit.  This only works works with the following options:
+       * If the application did not run to completion and if the application
+       * was not backgrounded, then we need to wait here for the application
+       * to exit.  This only works works with the following options:
        *
        * - CONFIG_NSH_DISABLEBG - Do not run commands in background
        * - CONFIG_SCHED_WAITPID - Required to run external commands in
@@ -156,11 +158,17 @@ int nsh_builtin(FAR struct nsh_vtbl_s *vtbl, FAR const char *cmd,
         {
           int rc = 0;
 
-          /* Wait for the application to exit.  We did locked the scheduler
+          /* Wait for the application to exit.  We did lock the scheduler
            * above, but that does not guarantee that the application did not
-           * run in the case where I/O was redirected.  The scheduler will
-           * be unlocked while waitpid is waiting and if the application has
-           * not yet run, it will be able to to do so.
+           * already run to completion in the case where I/O was redirected.
+           * Here the scheduler will be unlocked while waitpid is waiting
+           * and if the application has not yet run, it will now be able to
+           * do so.
+           *
+           * Also, if CONFIG_SCHED_HAVE_PARENT is defined waitpid() might fail
+           * even if task is still active:  If the I/O was re-directed by a 
+           * proxy task, then the ask is a child of the proxy, and not this
+           * task.  waitpid() fails with ECHILD in either case.
            */
 
           ret = waitpid(ret, &rc, 0);
diff --git a/apps/nshlib/nsh_fileapps.c b/apps/nshlib/nsh_fileapps.c
index 92146a68d..9ff230f1a 100644
--- a/apps/nshlib/nsh_fileapps.c
+++ b/apps/nshlib/nsh_fileapps.c
@@ -168,12 +168,14 @@ int nsh_fileapp(FAR struct nsh_vtbl_s *vtbl, FAR const char *cmd,
     {
       /* The application was successfully started with pre-emption disabled.
        * In the simplest cases, the application will not have run because the
-       * the scheduler is locked.  but in the case were I/O redirected, a 
-       * proxy task ran and, as result, so may have the application.
+       * the scheduler is locked.  But in the case where I/O was redirected, a 
+       * proxy task ran and broke our lock.  As result, the application may
+       * have aso ran if its priority was higher than than the priority of
+       * this thread.
        *
-       * If the application did not run and if the application was not
-       * backgrounded, then we need to wait here for the application to
-       * exit.  This only works works with the following options:
+       * If the application did not run to completion and if the application
+       * was not backgrounded, then we need to wait here for the application
+       * to exit.  This only works works with the following options:
        *
        * - CONFIG_NSH_DISABLEBG - Do not run commands in background
        * - CONFIG_SCHED_WAITPID - Required to run external commands in
@@ -193,11 +195,12 @@ int nsh_fileapp(FAR struct nsh_vtbl_s *vtbl, FAR const char *cmd,
         {
           int rc = 0;
 
-          /* Wait for the application to exit.  We did locked the scheduler
+          /* Wait for the application to exit.  We did lock the scheduler
            * above, but that does not guarantee that the application did not
-           * run in the case where I/O was redirected.  The scheduler will
-           * be unlocked while waitpid is waiting and if the application has
-           * not yet run, it will be able to to do so.
+           * already run to completion in the case where I/O was redirected.
+           * Here the scheduler will be unlocked while waitpid is waiting
+           * and if the application has not yet run, it will now be able to
+           * do so.
            */
 
           ret = waitpid(pid, &rc, 0);