Implement BSD/GNU unlocked stdio extensions.

* libc/include/stdio.h (clearerr_unlocked, feof_unlocked,
ferror_unlocked, fflush_unlocked, fgetc_unlocked, fgets_unlocked,
fileno_unlocked, fputc_unlocked, fputs_unlocked, fread_unlocked,
fwrite_unlocked): Declare.
* libc/include/wchar.h (fgetwc_unlocked, fgetws_unlocked,
fputwc_unlocked, fputws_unlocked, getwc_unlocked, getwchar_unlocked,
putwc_unlocked, putwchar_unlocked): Declare.
* libc/stdio/Makefile.am (ELIX_4_SOURCES): Add clearerr_u.c,
feof_u.c, ferror_u.c, fflush_u.c, fgetc_u.c, fgets_u.c, fgetwc_u.c,
fgetws_u.c, fileno_u.c, fputc_u.c, fputs_u.c, fputwc_u.c, fputws_u.c,
fread_u.c, fwrite_u.c, getwc_u.c, getwchar_u.c, putwc_u.c, putwchar_u.c.
Add necessary dependencies.
* libc/stdio/Makefile.in: Regenerate.
* libc/stdio/clearerr.c: Document unlocked variant.
* libc/stdio/clearerr_u.c: New file.
* libc/stdio/feof.c: Document unlocked variant.
* libc/stdio/feof_u.c: New file.
* libc/stdio/ferror.c: Document unlocked variant.
* libc/stdio/ferror_u.c: New file.
* libc/stdio/fflush.c: Add __IMPL_UNLOCKED__ overrides.
Document unlocked variants.
* libc/stdio/fflush_u.c: New file.
* libc/stdio/fgetc.c: Document unlocked variants.
* libc/stdio/fgetc_u.c: New file.
* libc/stdio/fgets.c: Add __IMPL_UNLOCKED__ overrides.
Document unlocked variants.
* libc/stdio/fgets_u.c: New file.
* libc/stdio/fgetwc.c: Document unlocked variants.
(__fgetwc): Make non-static.
* libc/stdio/fgetwc_u.c: New file.
* libc/stdio/fgetws.c: Add __IMPL_UNLOCKED__ overrides.
Document unlocked variants.
* libc/stdio/fgetws_u.c: New file.
* libc/stdio/fileno.c: Document unlocked variant.
* libc/stdio/fileno_u.c: New file.
* libc/stdio/fputc.c: Document unlocked variants.
* libc/stdio/fputc_u.c: New file.
* libc/stdio/fputs.c: Add __IMPL_UNLOCKED__ overrides.
Document unlocked variants.
* libc/stdio/fputs_u.c: New file.
* libc/stdio/fputwc.c: Document unlocked variants.
(__fputwc): Make non-static.
* libc/stdio/fputwc_u.c: New file.
* libc/stdio/fputws.c: Add __IMPL_UNLOCKED__ overrides.
Document unlocked variants.
* libc/stdio/fputws_u.c: New file.
* libc/stdio/fread.c: Add __IMPL_UNLOCKED__ overrides.
Document unlocked variants.
* libc/stdio/fread_u.c: New file.
* libc/stdio/fwrite.c: Add __IMPL_UNLOCKED__ overrides.
Document unlocked variants.
* libc/stdio/fwrite_u.c: New file.
* libc/stdio/getwc_u.c: New file.
* libc/stdio/getwchar.c: Document unlocked variants.
* libc/stdio/getwchar_u.c: New file.
* libc/stdio/local.h: Define locking macros as empty ifdef
__IMPL_UNLOCKED__.
(__fgetwc, __fputwc): Declare.
* libc/stdio/putwc_u.c: New file.
* libc/stdio/putwchar.c: Document unlocked variants.
* libc/stdio/putwchar_u.c: New file.

1 files changed, 45 insertions, 4 deletions

diff --git a/newlib/libc/stdio/fgets.c b/newlib/libc/stdio/fgets.c
index 0280ea0c5..f7c8a0300 100644
--- a/newlib/libc/stdio/fgets.c
+++ b/newlib/libc/stdio/fgets.c
@@ -17,20 +17,31 @@
 
 /*
 FUNCTION
-<<fgets>>---get character string from a file or stream
+<<fgets>>, <<fgets_unlocked>>---get character string from a file or stream
 
 INDEX
 	fgets
 INDEX
+	fgets_unlocked
+INDEX
 	_fgets_r
+INDEX
+	_fgets_unlocked_r
 
 ANSI_SYNOPSIS
         #include <stdio.h>
 	char *fgets(char *restrict <[buf]>, int <[n]>, FILE *restrict <[fp]>);
 
+	#define _GNU_SOURCE
+        #include <stdio.h>
+	char *fgets_unlocked(char *restrict <[buf]>, int <[n]>, FILE *restrict <[fp]>);
+
         #include <stdio.h>
 	char *_fgets_r(struct _reent *<[ptr]>, char *restrict <[buf]>, int <[n]>, FILE *restrict <[fp]>);
 
+        #include <stdio.h>
+	char *_fgets_unlocked_r(struct _reent *<[ptr]>, char *restrict <[buf]>, int <[n]>, FILE *restrict <[fp]>);
+
 TRAD_SYNOPSIS
 	#include <stdio.h>
 	char *fgets(<[buf]>,<[n]>,<[fp]>)
@@ -38,6 +49,13 @@ TRAD_SYNOPSIS
 	int <[n]>;
 	FILE *<[fp]>;
 
+	#define _GNU_SOURCE
+	#include <stdio.h>
+	char *fgets_unlocked(<[buf]>,<[n]>,<[fp]>)
+        char *<[buf]>;
+	int <[n]>;
+	FILE *<[fp]>;
+
 	#include <stdio.h>
 	char *_fgets_r(<[ptr]>, <[buf]>,<[n]>,<[fp]>)
 	struct _reent *<[ptr]>;
@@ -45,14 +63,30 @@ TRAD_SYNOPSIS
 	int <[n]>;
 	FILE *<[fp]>;
 
+	#include <stdio.h>
+	char *_fgets_unlocked_r(<[ptr]>, <[buf]>,<[n]>,<[fp]>)
+	struct _reent *<[ptr]>;
+        char *<[buf]>;
+	int <[n]>;
+	FILE *<[fp]>;
+
 DESCRIPTION
 	Reads at most <[n-1]> characters from <[fp]> until a newline
 	is found. The characters including to the newline are stored
 	in <[buf]>. The buffer is terminated with a 0.
 
-	The <<_fgets_r>> function is simply the reentrant version of
-	<<fgets>> and is passed an additional reentrancy structure
-	pointer: <[ptr]>.
+	<<fgets_unlocked>> is a non-thread-safe version of <<fgets>>.
+	<<fgets_unlocked>> may only safely be used within a scope
+	protected by flockfile() (or ftrylockfile()) and funlockfile().  This
+	function may safely be used in a multi-threaded program if and only
+	if they are called while the invoking thread owns the (FILE *)
+	object, as is the case after a successful call to the flockfile() or
+	ftrylockfile() functions.  If threads are disabled, then
+	<<fgets_unlocked>> is equivalent to <<fgets>>.
+
+	The functions <<_fgets_r>> and <<_fgets_unlocked_r>> are simply
+	reentrant versions that are passed the additional reentrant structure
+	pointer argument: <[ptr]>.
 
 RETURNS
 	<<fgets>> returns the buffer passed to it, with the data
@@ -65,6 +99,8 @@ PORTABILITY
 	that <<fgets>> returns all of the data, while <<gets>> removes
 	the trailing newline (with no indication that it has done so.)
 
+	<<fgets_unlocked>> is a GNU extension.
+
 Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>,
 <<lseek>>, <<read>>, <<sbrk>>, <<write>>.
 */
@@ -74,6 +110,11 @@ Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>,
 #include <string.h>
 #include "local.h"
 
+#ifdef __IMPL_UNLOCKED__
+#define _fgets_r _fgets_unlocked_r
+#define fgets fgets_unlocked
+#endif
+
 /*
  * Read at most n-1 characters from the given file.
  * Stop when a newline has been read, or the count runs out.