From 8572f223aed89a6e44f934cce203598b2aba8849 Mon Sep 17 00:00:00 2001
From: Gregory Nutt <gnutt@nuttx.org>
Date: Sat, 4 Aug 2018 16:24:02 -0600
Subject: [PATCH] apps/examples/elf:  If the test ELF files are on media in
 removable meda such as SD or USB FLASH, the wait until the media has been
 installed and initialized before starting the test.

---
 examples/elf/Kconfig    | 16 +++++++++++++---
 examples/elf/elf_main.c | 40 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+), 3 deletions(-)

diff --git a/examples/elf/Kconfig b/examples/elf/Kconfig
index 6a6e649ab..0cbc675ac 100644
--- a/examples/elf/Kconfig
+++ b/examples/elf/Kconfig
@@ -32,6 +32,16 @@ config EXAMPLES_ELF_EXTERN
 
 endchoice # ROM File System
 
+config EXAMPLES_ELF_FSMOUNT
+	bool "Mount external file system"
+	default y
+	depends on EXAMPLES_ELF_EXTERN
+
+config EXAMPLES_ELF_FSREMOVEABLE
+	bool "Removable file system"
+	default n
+	depends on EXAMPLES_ELF_FSMOUNT
+
 config EXAMPLES_ELF_DEVMINOR
 	int "ROMFS Minor Device Number"
 	default 0
@@ -45,7 +55,7 @@ config EXAMPLES_ELF_DEVMINOR
 config EXAMPLES_ELF_FSTYPE
 	string "External file system type"
 	default "vfat"
-	depends on EXAMPLES_ELF_EXTERN
+	depends on EXAMPLES_ELF_FSMOUNT
 	---help---
 		The minor device number of the ROMFS block. For example, the N in
 		/dev/ramN.  Used for registering the RAM block driver that will hold
@@ -55,8 +65,8 @@ config EXAMPLES_ELF_FSTYPE
 config EXAMPLES_ELF_DEVPATH
 	string "Block driver device path"
 	default "/dev/ram0" if EXAMPLES_ELF_ROMFS
-	default "/dev/mmcsd0" if EXAMPLES_ELF_EXTERN
-	depends on EXAMPLES_ELF_ROMFS || EXAMPLES_ELF_EXTERN
+	default "/dev/mmcsd0" if EXAMPLES_ELF_FSMOUNT
+	depends on EXAMPLES_ELF_ROMFS || EXAMPLES_ELF_FSMOUNT
 	---help---
 		The path to the ROMFS/External block driver device.  This must match
 		EXAMPLES_ELF_DEVMINOR for the case of ROMFS.  Used for mounting the
diff --git a/examples/elf/elf_main.c b/examples/elf/elf_main.c
index 354589e73..a689de3fd 100644
--- a/examples/elf/elf_main.c
+++ b/examples/elf/elf_main.c
@@ -41,6 +41,7 @@
 #include <nuttx/compiler.h>
 
 #include <sys/mount.h>
+#include <sys/stat.h>
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -242,6 +243,9 @@ int main(int argc, FAR char *argv[])
 int elf_main(int argc, char *argv[])
 #endif
 {
+#ifdef CONFIG_EXAMPLES_ELF_FSREMOVEABLE
+  struct stat buf;
+#endif
   FAR char *args[1];
   int ret;
   int i;
@@ -305,6 +309,41 @@ int elf_main(int argc, char *argv[])
       errmsg("ERROR: mount(%s, cromfs) failed: %d\n", MOUNTPT, errno);
     }
 #elif defined(CONFIG_EXAMPLES_ELF_EXTERN)
+  /* An external file system is being used */
+
+#if defined(CONFIG_EXAMPLES_ELF_FSMOUNT)
+#if defined(CONFIG_EXAMPLES_ELF_FSREMOVEABLE)
+  /* The file system is removable, wait until the block driver is available */
+
+  do
+    {
+      ret = stat(CONFIG_EXAMPLES_ELF_DEVPATH, &buf);
+      if (ret < 0)
+        {
+          int errcode = errno;
+          if (errcode == ENOENT)
+            {
+              printf("%s does not exist.  Waiting...\n",
+                     CONFIG_EXAMPLES_ELF_DEVPATH);
+              sleep(1);
+            }
+          else
+            {
+              printf("ERROR: stat(%s) failed: %d  Aborting...\n",
+                     CONFIG_EXAMPLES_ELF_DEVPATH, errcode);
+              exit(EXIT_FAILURE);
+            }
+        }
+      else if (!S_ISBLK(buf.st_mode))
+        {
+          printf("ERROR: stat(%s) exists but is not a block driver: %04x\n",
+                 CONFIG_EXAMPLES_ELF_DEVPATH, buf.st_mode);
+          exit(EXIT_FAILURE);
+        }
+    }
+  while (ret < 0);
+#endif
+
   /* Mount the external file system */
 
   message("Mounting %s filesystem at target=%s\n",
@@ -318,6 +357,7 @@ int elf_main(int argc, char *argv[])
              CONFIG_EXAMPLES_ELF_DEVPATH, CONFIG_EXAMPLES_ELF_FSTYPE,
              MOUNTPT, errno);
     }
+#endif
 #else
 #  Warning "No file system selected"
 #endif