2012-07-18 Terry Guo <terry.guo@arm.com>

        PR 14329
        * defs.h (GDB_MI_MSG_WIDTH): New.
        * ser_base (ser_base_read_error_fd): New function.
        (do_ser_base_readchar): Poll error file descriptor as well as
        standard output.
        (generic_readchar): Refactor error handling.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index acd5b5e..9bd7d6e 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,12 @@
+2012-07-18  Terry Guo  <terry.guo@arm.com>
+
+       PR 14329
+       * defs.h (GDB_MI_MSG_WIDTH): New.
+       * ser_base (ser_base_read_error_fd): New function.
+       (do_ser_base_readchar): Poll error file descriptor as well as
+       standard output.
+       (generic_readchar): Refactor error handling. 
+
 2012-07-18  Joel Brobecker  <brobecker@adacore.com>
 
        * NEWS: Create a new section for the next release branch.

diff --git a/gdb/defs.h b/gdb/defs.h
index 1c6fa79..bd556b0 100644 (file)
--- a/gdb/defs.h
+++ b/gdb/defs.h
@@ -1115,6 +1115,9 @@ extern int use_windows;
 #define ISATTY(FP)     (isatty (fileno (FP)))
 #endif
 
+/* A width that can achieve a better legibility for GDB MI mode.  */
+#define GDB_MI_MSG_WIDTH  80
+
 /* Ensure that V is aligned to an N byte boundary (B's assumed to be a
    power of 2).  Round up/down when necessary.  Examples of correct
    use include:

diff --git a/gdb/ser-base.c b/gdb/ser-base.c
index 2f12dfc..287e55d 100644 (file)
--- a/gdb/ser-base.c
+++ b/gdb/ser-base.c
@@ -25,6 +25,7 @@
 
 #include "gdb_select.h"
 #include "gdb_string.h"
+#include "gdb_assert.h"
 #include <sys/time.h>
 #ifdef USE_WIN32API
 #include <winsock2.h>
@@ -242,6 +243,64 @@ ser_base_wait_for (struct serial *scb, int timeout)
     }
 }
 
+/* Read any error output we might have.  */
+
+static void
+ser_base_read_error_fd (struct serial *scb, int close_fd)
+{
+  if (scb->error_fd != -1)
+    {
+      ssize_t s;
+      char buf[GDB_MI_MSG_WIDTH + 1];
+
+      for (;;)
+       {
+         char *current;
+         char *newline;
+         int to_read = GDB_MI_MSG_WIDTH;
+         int num_bytes = -1;
+
+         if (scb->ops->avail)
+           num_bytes = (scb->ops->avail)(scb, scb->error_fd);
+
+         if (num_bytes != -1)
+           to_read = (num_bytes < to_read) ? num_bytes : to_read;
+
+         if (to_read == 0)
+           break;
+
+         s = read (scb->error_fd, &buf, to_read);
+         if ((s == -1) || (s == 0 && !close_fd))
+           break;
+
+         if (s == 0 && close_fd)
+           {
+             /* End of file.  */
+             close (scb->error_fd);
+             scb->error_fd = -1;
+             break;
+           }
+
+         /* In theory, embedded newlines are not a problem.
+            But for MI, we want each output line to have just
+            one newline for legibility.  So output things
+            in newline chunks.  */
+         gdb_assert (s > 0 && s <= GDB_MI_MSG_WIDTH);
+         buf[s] = '\0';
+         current = buf;
+         while ((newline = strstr (current, "\n")) != NULL)
+           {
+             *newline = '\0';
+             fputs_unfiltered (current, gdb_stderr);
+             fputs_unfiltered ("\n", gdb_stderr);
+             current = newline + 1;
+           }
+
+         fputs_unfiltered (current, gdb_stderr);
+       }
+    }
+}
+
 /* Read a character with user-specified timeout.  TIMEOUT is number of seconds
    to wait, or -1 to wait forever.  Use timeout of 0 to effect a poll.  Returns
    char if successful.  Returns -2 if timeout expired, EOF if line dropped
@@ -292,6 +351,11 @@ do_ser_base_readchar (struct serial *scb, int timeout)
          status = SERIAL_TIMEOUT;
          break;
        }
+
+      /* We also need to check and consume the stderr because it could
+        come before the stdout for some stubs.  If we just sit and wait
+        for stdout, we would hit a deadlock for that case.  */
+      ser_base_read_error_fd (scb, 0);
     }
 
   if (status < 0)
@@ -362,54 +426,9 @@ generic_readchar (struct serial *scb, int timeout,
            }
        }
     }
-  /* Read any error output we might have.  */
-  if (scb->error_fd != -1)
-    {
-      ssize_t s;
-      char buf[81];
-
-      for (;;)
-        {
-         char *current;
-         char *newline;
-         int to_read = 80;
-
-         int num_bytes = -1;
-         if (scb->ops->avail)
-           num_bytes = (scb->ops->avail)(scb, scb->error_fd);
-         if (num_bytes != -1)
-           to_read = (num_bytes < to_read) ? num_bytes : to_read;
-
-         if (to_read == 0)
-           break;
-
-         s = read (scb->error_fd, &buf, to_read);
-         if (s == -1)
-           break;
-         if (s == 0)
-           {
-             /* EOF */
-             close (scb->error_fd);
-             scb->error_fd = -1;
-             break;
-           }
 
-         /* In theory, embedded newlines are not a problem.
-            But for MI, we want each output line to have just
-            one newline for legibility.  So output things
-            in newline chunks.  */
-         buf[s] = '\0';
-         current = buf;
-         while ((newline = strstr (current, "\n")) != NULL)
-           {
-             *newline = '\0';
-             fputs_unfiltered (current, gdb_stderr);
-             fputs_unfiltered ("\n", gdb_stderr);
-             current = newline + 1;
-           }
-         fputs_unfiltered (current, gdb_stderr);
-       }
-    }
+  /* Read any error output we might have.  */
+  ser_base_read_error_fd (scb, 1);
 
   reschedule (scb);
   return ch;