libio: Convert __vdprintf_internal to buffers

The internal buffer size is set to 2048 bytes.  This is less than
the original BUFSIZ value used by buffered_vfprintf before
the conversion, but it hopefully covers all cases where write
boundaries matter.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

3 files changed, 52 insertions, 28 deletions

diff --git a/include/printf_buffer.h b/include/printf_buffer.h
index c8e22e1..e2ca2d7 100644
--- a/include/printf_buffer.h
+++ b/include/printf_buffer.h
@@ -50,6 +50,7 @@ enum __printf_buffer_mode
     __printf_buffer_mode_sprintf_chk,
     __printf_buffer_mode_to_file,
     __printf_buffer_mode_asprintf,
+    __printf_buffer_mode_dprintf,
     __printf_buffer_mode_strfmon,
     __printf_buffer_mode_fp,         /* For __printf_fp_l_buffer.  */
     __printf_buffer_mode_fp_to_wide, /* For __wprintf_fp_l_buffer.  */
@@ -308,6 +309,9 @@ void __printf_buffer_flush_to_file (struct __printf_buffer_to_file *)
 struct __printf_buffer_asprintf;
 void __printf_buffer_flush_asprintf (struct __printf_buffer_asprintf *)
   attribute_hidden;
+struct __printf_buffer_dprintf;
+void __printf_buffer_flush_dprintf (struct __printf_buffer_dprintf *)
+  attribute_hidden;
 struct __printf_buffer_fp;
 void __printf_buffer_flush_fp (struct __printf_buffer_fp *)
   attribute_hidden;
@@ -341,4 +345,9 @@ void __wprintf_buffer_flush_to_file (struct __wprintf_buffer_to_file *)
    (final, correctly sized) heap allocation.  */
 #define PRINTF_BUFFER_SIZE_ASPRINTF 200
 
+/* This should cover most of the packet-oriented file descriptors,
+   where boundaries between writes could be visible to readers.  But
+   it is still small enough not to cause too many stack overflow issues.  */
+#define PRINTF_BUFFER_SIZE_DPRINTF 2048
+
 #endif /* PRINTF_BUFFER_H */
diff --git a/libio/iovdprintf.c b/libio/iovdprintf.c
index 1e48386..455582e 100644
--- a/libio/iovdprintf.c
+++ b/libio/iovdprintf.c
@@ -24,41 +24,52 @@
    This exception applies to code released by its copyright holders
    in files containing the exception.  */
 
-#include <libioP.h>
+#include <array_length.h>
+#include <math_ldbl_opt.h>
+#include <printf.h>
 #include <stdio_ext.h>
+#include <unistd.h>
+#include <printf_buffer.h>
 
-int
-__vdprintf_internal (int d, const char *format, va_list arg,
-		     unsigned int mode_flags)
+struct __printf_buffer_dprintf
 {
-  struct _IO_FILE_plus tmpfil;
-  struct _IO_wide_data wd;
-  int done;
+  struct __printf_buffer base;
+  int fd;
+
+  char buf[PRINTF_BUFFER_SIZE_DPRINTF];
+};
 
-#ifdef _IO_MTSAFE_IO
-  tmpfil.file._lock = NULL;
-#endif
-  _IO_no_init (&tmpfil.file, _IO_USER_LOCK, 0, &wd, &_IO_wfile_jumps);
-  _IO_JUMPS (&tmpfil) = &_IO_file_jumps;
-  _IO_new_file_init_internal (&tmpfil);
-  if (_IO_file_attach (&tmpfil.file, d) == NULL)
+void
+__printf_buffer_flush_dprintf (struct __printf_buffer_dprintf *buf)
+{
+  char *p = buf->buf;
+  char *end = buf->base.write_ptr;
+  while (p < end)
     {
-      _IO_un_link (&tmpfil);
-      return EOF;
+      ssize_t ret = TEMP_FAILURE_RETRY (write (buf->fd, p, end - p));
+      if (ret < 0)
+	{
+	  __printf_buffer_mark_failed (&buf->base);
+	  return;
+	}
+      p += ret;
     }
-  tmpfil.file._flags |= _IO_DELETE_DONT_CLOSE;
-
-  _IO_mask_flags (&tmpfil.file, _IO_NO_READS,
-		  _IO_NO_READS+_IO_NO_WRITES+_IO_IS_APPENDING);
-
-  done = __vfprintf_internal (&tmpfil.file, format, arg, mode_flags);
-
-  if (done != EOF && _IO_do_flush (&tmpfil.file) == EOF)
-    done = EOF;
-
-  _IO_FINISH (&tmpfil.file);
+  buf->base.write_ptr = buf->buf;
+}
 
-  return done;
+int
+__vdprintf_internal (int d, const char *format, va_list arg,
+		     unsigned int mode_flags)
+{
+  struct __printf_buffer_dprintf buf;
+  __printf_buffer_init (&buf.base, buf.buf, array_length (buf.buf),
+			__printf_buffer_mode_dprintf);
+  buf.fd = d;
+  __printf_buffer (&buf.base, format, arg, mode_flags);
+  if (__printf_buffer_has_failed (&buf.base))
+    return -1;
+  __printf_buffer_flush_dprintf (&buf);
+  return __printf_buffer_done (&buf.base);
 }
 
 int
diff --git a/stdio-common/printf_buffer_flush.c b/stdio-common/printf_buffer_flush.c
index 14fe1b2..922340c 100644
--- a/stdio-common/printf_buffer_flush.c
+++ b/stdio-common/printf_buffer_flush.c
@@ -28,6 +28,7 @@
 # pragma weak __printf_buffer_flush_snprintf
 # pragma weak __printf_buffer_flush_to_file
 # pragma weak __printf_buffer_flush_asprintf
+# pragma weak __printf_buffer_flush_dprintf
 # pragma weak __printf_buffer_flush_fp
 # pragma weak __printf_buffer_flush_fp_to_wide
 # pragma weak __printf_buffer_flush_fphex_to_wide
@@ -53,6 +54,9 @@ __printf_buffer_do_flush (struct __printf_buffer *buf)
     case __printf_buffer_mode_asprintf:
       __printf_buffer_flush_asprintf ((struct __printf_buffer_asprintf *) buf);
       return;
+    case __printf_buffer_mode_dprintf:
+      __printf_buffer_flush_dprintf ((struct __printf_buffer_dprintf *) buf);
+      return;
     case __printf_buffer_mode_strfmon:
       __set_errno (E2BIG);
       __printf_buffer_mark_failed (buf);