Use re-entrant locks on stdio

libc/stdio/unlocked/clearerr_unlocked.S

@@ -22,6 +22,7 @@
 //
 //	@param	rdi has stream pointer
 //	@see	clearerr_unlocked()
+//	@threadsafe
 clearerr:
 	mov	%rdi,%r11
 	ezlea	clearerr_unlocked,ax

libc/stdio/unlocked/feof_unlocked.S

@@ -23,6 +23,7 @@
 //	@param	rdi has file stream object pointer
 //	@note	EOF doesn't count
 //	@see	feof_unlocked()
+//	@threadsafe
 feof:	mov	%rdi,%r11
 	ezlea	feof_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/ferror_unlocked.S

@@ -23,6 +23,7 @@
 //	@param	rdi has file stream object pointer
 //	@note	EOF doesn't count
 //	@see	ferror_unlocked()
+//	@threadsafe
 ferror:	mov	%rdi,%r11
 	ezlea	ferror_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/fflush_unlocked.S

@@ -20,10 +20,14 @@
 
 //	Blocks until data from stream buffer is written out.
 //
-//	@param	rdi is the stream handle
+//	@param	rdi is the stream handle, or 0 for all streams
 //	@return	0 on success or -1 w/ errno
 //	@see	fflush_unlocked()
-fflush:	mov	%rdi,%r11
-	ezlea	fflush_unlocked,ax
+//	@threadsafe
+fflush:	ezlea	fflush_unlocked,ax
+	test	%rdi,%rdi
+	jz	1f
+	mov	%rdi,%r11
 	jmp	stdio_unlock
+1:	jmp	*%rax
 	.endfn	fflush,globl

libc/stdio/unlocked/fgetc_unlocked.S

@@ -23,6 +23,7 @@
 //	@param	rdi has stream object pointer
 //	@return byte in range 0..255, or -1 w/ errno
 //	@see	fgetc_unlocked()
+//	@threadsafe
 fgetc:	mov	%rdi,%r11
 	ezlea	fgetc_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/fgets_unlocked.S

@@ -30,6 +30,7 @@
 //	@return	rax has rdi on success, NULL on error or
 //		NULL if EOF happens with zero chars read
 //	@see	fgets_unlocked()
+//	@threadsafe
 fgets:	mov	%rdx,%r11
 	ezlea	fgets_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/fgetwc_unlocked.S

@@ -23,6 +23,7 @@
 //	@param	rdi has stream object pointer
 //	@return wide character or -1 on EOF or error
 //	@see	fgetwc_unlocked()
+//	@threadsafe
 fgetwc:	mov	%rdi,%r11
 	ezlea	fgetwc_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/fgetws_unlocked.S

@@ -28,6 +28,7 @@
 //	@param	rsi is size of rdi buffer
 //	@param	rsi is file stream object pointer
 //	@see	fgetws_unlocked()
+//	@threadsafe
 fgetws:	mov	%rdx,%r11
 	ezlea	fgetws_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/fileno_unlocked.S

@@ -22,6 +22,7 @@
 //
 //	@param	rdi has file stream object pointer
 //	@see	fileno_unlocked()
+//	@threadsafe
 fileno:	mov	%rdi,%r11
 	ezlea	fileno_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/fputc_unlocked.S

@@ -24,6 +24,7 @@
 //	@param	rsi has stream object pointer
 //	@return c as unsigned char if written or -1 w/ errno
 //	@see	fputc_unlocked()
+//	@threadsafe
 fputc:	mov	%rsi,%r11
 	ezlea	fputc_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/fputs_unlocked.S

@@ -28,6 +28,7 @@
 //	@param	rsi is file object stream pointer
 //	@return	strlen(rdi) on success or -1 w/ errno
 //	@see	fputs_unlocked()
+//	@threadsafe
 fputs:	mov	%rsi,%r11
 	ezlea	fputs_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/fputwc_unlocked.S

@@ -24,6 +24,7 @@
 //	@param	rsi has file object stream pointer
 //	@return	rax is wide character if written or -1 w/ errno
 //	@see	fputwc_unlocked()
+//	@threadsafe
 fputwc:	mov	%rsi,%r11
 	ezlea	fputwc_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/fputws_unlocked.S

@@ -28,6 +28,7 @@
 //	@param	rsi is file object stream pointer
 //	@return	strlen(rdi) on success or -1 w/ errno
 //	@see	fputws_unlocked()
+//	@threadsafe
 fputws:	mov	%rsi,%r11
 	ezlea	fputws_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/fread_unlocked.S

@@ -26,6 +26,7 @@
 //	@param	rcx has file object stream pointer
 //	@return	count on success, [0,count) on EOF, 0 on error or count==0
 //	@see	fread_unlocked()
+//	@threadsafe
 fread:	mov	%rcx,%r11
 	ezlea	fread_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/fseeko_unlocked.S

@@ -0,0 +1,37 @@
+/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8     -*-│
+│vi: set et ft=asm ts=8 tw=8 fenc=utf-8                                     :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/macros.internal.h"
+
+//	Repositions open file stream.
+//
+//	This function flushes the buffer (unless it's currently in the EOF
+//	state) and then calls lseek() on the underlying file. If the stream
+//	is in the EOF state, this function can be used to restore it without
+//	needing to reopen the file.
+//
+//	@param	rdi is stream handle
+//	@param	rsi is offset is the byte delta
+//	@param	rdx is whence and can be SEET_SET, SEEK_CUR, or SEEK_END
+//	@return	0 on success or -1 w/ errno
+//	@see	fflush_unlocked()
+//	@threadsafe
+fseeko:	mov	%rdi,%r11
+	ezlea	fseeko_unlocked,ax
+	jmp	stdio_unlock
+	.endfn	fseeko,globl

libc/stdio/unlocked/fwrite_unlocked.S

@@ -26,6 +26,7 @@
 //	@param	rcx has file object stream pointer
 //	@return	count on success, [0,count) on EOF, 0 on error or count==0
 //	@see	fwrite_unlocked()
+//	@threadsafe
 fwrite:	mov	%rcx,%r11
 	ezlea	fwrite_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/getc_unlocked.S

@@ -23,6 +23,7 @@
 //	@param	rdi has file stream object pointer
 //	@return	byte in range 0..255, or -1 w/ errno
 //	@see	fgetc_unlocked()
+//	@threadsafe
 getc:	mov	%rdi,%r11
 	ezlea	fgetwc_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/getchar_unlocked.S

@@ -22,6 +22,7 @@
 //
 //	@return	byte in range 0..255, or -1 w/ errno
 //	@see	fgetc_unlocked()
+//	@threadsafe
 getchar:
 	mov	stdin(%rip),%rdi
 	mov	%rdi,%r11

libc/stdio/unlocked/getwc_unlocked.S

@@ -23,6 +23,7 @@
 //	@param	rdi has file stream object pointer
 //	@return	wide character or -1 on EOF or error
 //	@see	fgetwc_unlocked()
+//	@threadsafe
 getwc:	mov	%rdi,%r11
 	ezlea	fgetwc_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/getwchar_unlocked.S

@@ -22,6 +22,7 @@
 //
 //	@return	wide character or -1 on EOF or error
 //	@see	fgetwc_unlocked()
+//	@threadsafe
 getwchar:
 	mov	stdin(%rip),%rdi
 	mov	%rdi,%r11

libc/stdio/unlocked/putc_unlocked.S

@@ -24,6 +24,7 @@
 //	@param	rsi has stream object pointer
 //	@return c as unsigned char if written or -1 w/ errno
 //	@see	fputc_unlocked()
+//	@threadsafe
 putc:	mov	%rsi,%r11
 	ezlea	fputc_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/putchar_unlocked.S

@@ -23,6 +23,7 @@
 //	@param	rdi has character
 //	@return c (as unsigned char) if written or -1 w/ errno
 //	@see	fputc_unlocked()
+//	@threadsafe
 putchar:
 	mov	stdout(%rip),%rsi
 	mov	%rsi,%r11

libc/stdio/unlocked/putwc_unlocked.S

@@ -24,6 +24,7 @@
 //	@param	rsi has file object
 //	@return wc if written or -1 w/ errno
 //	@see	putwc_unlocked()
+//	@threadsafe
 putwc:	mov	%rsi,%r11
 	ezlea	fputwc_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/putwchar_unlocked.S

@@ -23,6 +23,7 @@
 //	@param	rdi has wide character
 //	@return wc if written or -1 w/ errno
 //	@see	fputwc_unlocked()
+//	@threadsafe
 putwchar:
 	mov	stdout(%rip),%rsi
 	mov	%rsi,%r11

libc/stdio/unlocked/stdio_unlock.S

@@ -18,53 +18,54 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/macros.internal.h"
 
-#define LOCK 0x2c /* see struct file in stdio.h */
-
 //	Wrapper for applying locking to stdio functions.
 //
 //	This function is intended to be called by thunks.
 //
-//	@param	rax has the delegate function pointer
+//	@param	rax is stdio function pointer
 //	@param	rdi is passed along as an arg
 //	@param	rsi is passed along as an arg
 //	@param	rdx is passed along as an arg
 //	@param	rcx is passed along as an arg
-//	@param	r8  is passed along as an arg
-//	@param	r9  is passed along as an arg
-//	@param	r10 is passed along as an arg
 //	@param	r11 has the FILE* obj pointer
 //	@return	rax is passed along as result
 //	@return	rdx is passed along as result
+//	@threadsafe
 stdio_unlock:
 	push	%rbp
 	mov	%rsp,%rbp
 	.profilable
 
 //	acquires mutex
-	push	%rcx
+	push	%rax
+	push	%rdi
+	push	%rsi
 	push	%rdx
-	mov	$1,%cl
-0:	mov	LOCK(%r11),%dl			# optimistic
-	test	%dl,%dl
-	je	2f
-1:	pause					# hyperyield
-	jmp	0b
-2:	mov	%ecx,%edx
-	xchg	LOCK(%r11),%dl			# locks bus!
-	test	%dl,%dl
-	jne	1b
-	pop	%rdx
+	push	%rcx
+	push	%r11
+	mov	%r11,%rdi
+	call	flockfile
+	pop	%r11
 	pop	%rcx
+	pop	%rdx
+	pop	%rsi
+	pop	%rdi
+	pop	%rax
 
 //	calls delegate
-	push	%rsi
 	push	%r11
+	push	%rsi			# align stack
 	call	*%rax
-	pop	%r11
 	pop	%rsi
+	pop	%r11
 
 //	releases mutex
-	movb	$0,LOCK(%r11)
+	push	%rax
+	push	%rdx
+	mov	%r11,%rdi
+	call	funlockfile
+	pop	%rdx
+	pop	%rax
 
 	pop	%rbp
 	ret

libc/stdio/unlocked/ungetc_unlocked.S

@@ -24,6 +24,7 @@
 //	@param	rds has stream object pointer
 //	@return rax has rdi on success or -1 w/ errno
 //	@see	ungetc_unlocked()
+//	@threadsafe
 ungetc:	mov	%rsi,%r11
 	ezlea	ungetc_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/ungetwc_unlocked.S

@@ -24,6 +24,7 @@
 //	@param	rds has stream object pointer
 //	@return rax has rdi on success or -1 w/ errno
 //	@see	ungetwc_unlocked()
+//	@threadsafe
 ungetwc:
 	mov	%rsi,%r11
 	ezlea	ungetwc_unlocked,ax