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

2 files changed, 29 insertions, 18 deletions

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);