[BZ #713]

2005-09-26  Ulrich Drepper  <drepper@redhat.com>
	[BZ #713]
	* libio/iofgets.c: Treat N==1 correctly.
	* libio/iofgets_u.c: Likewise.
	* libio/iofgetws.c: Likewise.
	* libio/iofgetws_u.c: Likewise.
	* stdio-common/Makefile (tests): Add tst-fgets.
	* stdio-common/tst-fgets.c: New file.

5 files changed, 65 insertions, 31 deletions

diff --git a/libio/iofgets.c b/libio/iofgets.c
index 879cc975a3..601b1746a1 100644
--- a/libio/iofgets.c
+++ b/libio/iofgets.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1993, 1995, 1996, 1997, 1998, 1999, 2002, 2003
+/* Copyright (C) 1993, 1995, 1996, 1997, 1998, 1999, 2002, 2003, 2005
    Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
@@ -41,6 +41,14 @@ _IO_fgets (buf, n, fp)
   CHECK_FILE (fp, NULL);
   if (n <= 0)
     return NULL;
+  if (__builtin_expect (n == 1, 0))
+    {
+      /* Another irregular case: since we have to store a NUL byte and
+	 there is only room for exactly one byte, we don't have to
+	 read anything.  */
+      buf[0] = '\0';
+      return buf;
+    }
   _IO_acquire_lock (fp);
   /* This is very tricky since a file descriptor may be in the
      non-blocking mode. The error flag doesn't mean much in this
diff --git a/libio/iofgets_u.c b/libio/iofgets_u.c
index ded2a7c83c..4fb5b1c0fd 100644
--- a/libio/iofgets_u.c
+++ b/libio/iofgets_u.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1993,1995,1996,1997,1998,2002 Free Software Foundation, Inc.
+/* Copyright (C) 1993,1995-1998,2002,2005 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -40,6 +40,14 @@ fgets_unlocked (buf, n, fp)
   CHECK_FILE (fp, NULL);
   if (n <= 0)
     return NULL;
+  if (__builtin_expect (n == 1, 0))
+    {
+      /* Another irregular case: since we have to store a NUL byte and
+	 there is only room for exactly one byte, we don't have to
+	 read anything.  */
+      buf[0] = '\0';
+      return buf;
+    }
   /* This is very tricky since a file descriptor may be in the
      non-blocking mode. The error flag doesn't mean much in this
      case. We return an error only when there is a new error. */
diff --git a/libio/iofgetws.c b/libio/iofgetws.c
index 654c051a28..775391137a 100644
--- a/libio/iofgetws.c
+++ b/libio/iofgetws.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1993, 1995, 1996, 1997, 1998, 1999, 2001
+/* Copyright (C) 1993, 1995, 1996, 1997, 1998, 1999, 2001, 2005
    Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
@@ -41,6 +41,14 @@ fgetws (buf, n, fp)
   CHECK_FILE (fp, NULL);
   if (n <= 0)
     return NULL;
+  if (__builtin_expect (n == 1, 0))
+    {
+      /* Another irregular case: since we have to store a NUL byte and
+	 there is only room for exactly one byte, we don't have to
+	 read anything.  */
+      buf[0] = L'\0';
+      return buf;
+    }
   _IO_acquire_lock (fp);
   /* This is very tricky since a file descriptor may be in the
      non-blocking mode. The error flag doesn't mean much in this
diff --git a/libio/iofgetws_u.c b/libio/iofgetws_u.c
index 1253564566..9fb8a5cac1 100644
--- a/libio/iofgetws_u.c
+++ b/libio/iofgetws_u.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1993, 95, 96, 97, 98, 99 Free Software Foundation, Inc.
+/* Copyright (C) 1993, 95, 96, 97, 98, 99, 2005 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -40,6 +40,14 @@ fgetws_unlocked (buf, n, fp)
   CHECK_FILE (fp, NULL);
   if (n <= 0)
     return NULL;
+  if (__builtin_expect (n == 1, 0))
+    {
+      /* Another irregular case: since we have to store a NUL byte and
+	 there is only room for exactly one byte, we don't have to
+	 read anything.  */
+      buf[0] = L'\0';
+      return buf;
+    }
   /* This is very tricky since a file descriptor may be in the
      non-blocking mode. The error flag doesn't mean much in this
      case. We return an error only when there is a new error. */
diff --git a/libio/iogetline.c b/libio/iogetline.c
index eca38cf773..022a444f77 100644
--- a/libio/iogetline.c
+++ b/libio/iogetline.c
@@ -1,4 +1,5 @@
-/* Copyright (C) 1993,1997,1998,2000,2001,2002 Free Software Foundation, Inc.
+/* Copyright (C) 1993,1997,1998,2000,2001,2002,2005
+   Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -73,7 +74,8 @@ _IO_getline_info (fp, buf, n, delim, extract_delim, eof)
 	  int c = __uflow (fp);
 	  if (c == EOF)
 	    {
-	      if (eof) *eof = c;
+	      if (eof)
+		*eof = c;
 	      break;
 	    }
 	  if (c == delim)
@@ -89,31 +91,31 @@ _IO_getline_info (fp, buf, n, delim, extract_delim, eof)
 	  *ptr++ = c;
 	  n--;
 	}
-	else
-	  {
-	    char *t;
-	    if ((_IO_size_t) len >= n)
-	      len = n;
-	    t = (char *) memchr ((void *) fp->_IO_read_ptr, delim, len);
-	    if (t != NULL)
-	      {
-		_IO_size_t old_len = ptr-buf;
-		len = t - fp->_IO_read_ptr;
-		if (extract_delim >= 0)
-		  {
-		    ++t;
-		    if (extract_delim > 0)
-		      ++len;
-		  }
-		memcpy ((void *) ptr, (void *) fp->_IO_read_ptr, len);
-		fp->_IO_read_ptr = t;
-		return old_len + len;
-	      }
-	    memcpy ((void *) ptr, (void *) fp->_IO_read_ptr, len);
-	    fp->_IO_read_ptr += len;
-	    ptr += len;
-	    n -= len;
-	  }
+      else
+	{
+	  char *t;
+	  if ((_IO_size_t) len >= n)
+	    len = n;
+	  t = (char *) memchr ((void *) fp->_IO_read_ptr, delim, len);
+	  if (t != NULL)
+	    {
+	      _IO_size_t old_len = ptr-buf;
+	      len = t - fp->_IO_read_ptr;
+	      if (extract_delim >= 0)
+		{
+		  ++t;
+		  if (extract_delim > 0)
+		    ++len;
+		}
+	      memcpy ((void *) ptr, (void *) fp->_IO_read_ptr, len);
+	      fp->_IO_read_ptr = t;
+	      return old_len + len;
+	    }
+	  memcpy ((void *) ptr, (void *) fp->_IO_read_ptr, len);
+	  fp->_IO_read_ptr += len;
+	  ptr += len;
+	  n -= len;
+	}
     }
   return ptr - buf;
 }