drivers/serial/serial.c open, read, write, and poll methods will not return a short transfer or an EINTR error if a signal is received while waiting (only)

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5022 42af7a65-404d-4744-a932-0658087f49c3

2 files changed, 47 insertions, 5 deletions

diff --git a/apps/ChangeLog.txt b/apps/ChangeLog.txt
index 1bb2a08b5..37d05bacd 100755
--- a/apps/ChangeLog.txt
+++ b/apps/ChangeLog.txt
@@ -274,3 +274,5 @@
 	  no arguments outputs a short list of commands.  With -v lists all
 	  command line details.  And command name can be added to just get
 	  help on one command.
+	* system/readline.c:  If character input/output is interrupted by a
+	  signal, then readline() will try the read/write again.
diff --git a/apps/system/readline/readline.c b/apps/system/readline/readline.c
index f7fa6a635..bdd39e67b 100644
--- a/apps/system/readline/readline.c
+++ b/apps/system/readline/readline.c
@@ -103,13 +103,34 @@ static inline int readline_rawgetc(int infd)
   char buffer;
   ssize_t nread;
 
-  nread = read(infd, &buffer, 1);
-  if (nread < 1)
+  /* Loop until we successfully read a character (or until an unexpected
+   * error occurs).
+   */
+
+  do
     {
-      /* Return EOF if the end of file (0) or error (-1) occurs */
+      /* Read one character from the incoming stream */
+
+      nread = read(infd, &buffer, 1);
+
+      /* Return EOF if the end of file (0) or error (-1) occurs. */
+ 
+      if (nread < 1)
+        {
+          /* EINTR is not really an error; it simply means that a signal we
+           * received while watiing for intput.
+           */
 
-      return EOF;
+          if (nread == 0 ||  errno != EINTR)
+            {
+              return EOF;
+            }
+        }
     }
+  while (nread < 1);
+
+  /* On success, returnt he character that was read */
+
   return (int)buffer;
 }
 
@@ -121,7 +142,26 @@ static inline int readline_rawgetc(int infd)
 static inline void readline_consoleputc(int ch, int outfd)
 {
   char buffer = ch;
-  (void)write(outfd, &buffer, 1);
+  ssize_t nwritten;
+
+  /* Loop until we successfully write a character (or until an unexpected
+   * error occurs).
+   */
+
+  do
+    {
+      /* Write the character to the outgoing stream */
+
+      nwritten = write(outfd, &buffer, 1);
+
+      /* Check for irrecoverable write errors. */
+ 
+      if (nwritten < 0 && errno != EINTR)
+        {
+          break;
+        }
+    }
+  while (nwritten < 1);
 }
 #endif