Merge "Move stdio implementation details around a little."

1 files changed, 227 insertions, 0 deletions

diff --git a/libc/stdio/stdio.cpp b/libc/stdio/stdio.cpp
new file mode 100644
index 000000000..1ea3ef574
--- /dev/null
+++ b/libc/stdio/stdio.cpp
@@ -0,0 +1,227 @@
+/*	$OpenBSD: findfp.c,v 1.15 2013/12/17 16:33:27 deraadt Exp $ */
+/*-
+ * Copyright (c) 1990, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Chris Torek.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <stdio.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/param.h>
+#include <unistd.h>
+
+#include "local.h"
+#include "glue.h"
+#include "private/thread_private.h"
+
+#define ALIGNBYTES (sizeof(uintptr_t) - 1)
+#define ALIGN(p) (((uintptr_t)(p) + ALIGNBYTES) &~ ALIGNBYTES)
+
+#define	NDYNAMIC 10		/* add ten more whenever necessary */
+
+#define	std(flags, file) \
+	{0,0,0,flags,file,{0,0},0,__sF+file,__sclose,__sread,__sseek,__swrite, \
+	    {(unsigned char *)(__sFext+file), 0},NULL,0,{0},{0},{0,0},0,0}
+
+_THREAD_PRIVATE_MUTEX(__sfp_mutex);
+
+// TODO: when we no longer have to support both clang and GCC, we can simplify all this.
+#define SBUF_INIT {0,0}
+#if defined(__LP64__)
+#define MBSTATE_T_INIT {{0},{0}}
+#else
+#define MBSTATE_T_INIT {{0}}
+#endif
+#define WCHAR_IO_DATA_INIT {MBSTATE_T_INIT,MBSTATE_T_INIT,{0},0,0}
+
+static struct __sfileext __sFext[3] = {
+  { SBUF_INIT, WCHAR_IO_DATA_INIT, PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP, false },
+  { SBUF_INIT, WCHAR_IO_DATA_INIT, PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP, false },
+  { SBUF_INIT, WCHAR_IO_DATA_INIT, PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP, false },
+};
+
+// __sF is exported for backwards compatibility. Until M, we didn't have symbols
+// for stdin/stdout/stderr; they were macros accessing __sF.
+FILE __sF[3] = {
+  std(__SRD, STDIN_FILENO),
+  std(__SWR, STDOUT_FILENO),
+  std(__SWR|__SNBF, STDERR_FILENO),
+};
+
+FILE* stdin = &__sF[0];
+FILE* stdout = &__sF[1];
+FILE* stderr = &__sF[2];
+
+struct glue __sglue = { NULL, 3, __sF };
+static struct glue* lastglue = &__sglue;
+
+static glue* moreglue(int n) {
+    static FILE empty;
+
+    char* data = new char[sizeof(glue) + ALIGNBYTES + n * sizeof(FILE) + n * sizeof(__sfileext)];
+    if (data == nullptr) return nullptr;
+
+    glue* g = reinterpret_cast<glue*>(data);
+    FILE* p = reinterpret_cast<FILE*>(ALIGN(data + sizeof(*g)));
+    __sfileext* pext = reinterpret_cast<__sfileext*>(ALIGN(data + sizeof(*g)) + n * sizeof(FILE));
+    g->next = NULL;
+    g->niobs = n;
+    g->iobs = p;
+    while (--n >= 0) {
+        *p = empty;
+        _FILEEXT_SETUP(p, pext);
+        p++;
+        pext++;
+    }
+    return g;
+}
+
+/*
+ * Find a free FILE for fopen et al.
+ */
+FILE* __sfp(void) {
+	FILE *fp;
+	int n;
+	struct glue *g;
+
+	_THREAD_PRIVATE_MUTEX_LOCK(__sfp_mutex);
+	for (g = &__sglue; g != NULL; g = g->next) {
+		for (fp = g->iobs, n = g->niobs; --n >= 0; fp++)
+			if (fp->_flags == 0)
+				goto found;
+	}
+
+	/* release lock while mallocing */
+	_THREAD_PRIVATE_MUTEX_UNLOCK(__sfp_mutex);
+	if ((g = moreglue(NDYNAMIC)) == NULL)
+		return (NULL);
+	_THREAD_PRIVATE_MUTEX_LOCK(__sfp_mutex);
+	lastglue->next = g;
+	lastglue = g;
+	fp = g->iobs;
+found:
+	fp->_flags = 1;		/* reserve this slot; caller sets real flags */
+	_THREAD_PRIVATE_MUTEX_UNLOCK(__sfp_mutex);
+	fp->_p = NULL;		/* no current pointer */
+	fp->_w = 0;		/* nothing to read or write */
+	fp->_r = 0;
+	fp->_bf._base = NULL;	/* no buffer */
+	fp->_bf._size = 0;
+	fp->_lbfsize = 0;	/* not line buffered */
+	fp->_file = -1;		/* no file */
+/*	fp->_cookie = <any>; */	/* caller sets cookie, _read/_write etc */
+	fp->_lb._base = NULL;	/* no line buffer */
+	fp->_lb._size = 0;
+	_FILEEXT_INIT(fp);
+	return (fp);
+}
+
+extern "C" __LIBC_HIDDEN__ void __libc_stdio_cleanup(void) {
+	/* (void) _fwalk(fclose); */
+	(void) _fwalk(__sflush);		/* `cheating' */
+}
+
+int fclose(FILE* fp) {
+    if (fp->_flags == 0) {
+        // Already freed!
+        errno = EBADF;
+        return EOF;
+    }
+
+    FLOCKFILE(fp);
+    WCIO_FREE(fp);
+    int r = fp->_flags & __SWR ? __sflush(fp) : 0;
+    if (fp->_close != NULL && (*fp->_close)(fp->_cookie) < 0) {
+        r = EOF;
+    }
+    if (fp->_flags & __SMBF) free(fp->_bf._base);
+    if (HASUB(fp)) FREEUB(fp);
+    if (HASLB(fp)) FREELB(fp);
+
+    // Poison this FILE so accesses after fclose will be obvious.
+    fp->_file = -1;
+    fp->_r = fp->_w = 0;
+
+    // Release this FILE for reuse.
+    fp->_flags = 0;
+    FUNLOCKFILE(fp);
+    return (r);
+}
+
+int fileno(FILE* fp) {
+    FLOCKFILE(fp);
+    int result = fileno_unlocked(fp);
+    FUNLOCKFILE(fp);
+    return result;
+}
+
+// Small standard I/O/seek/close functions.
+// These maintain the `known seek offset' for seek optimisation.
+int __sread(void* cookie, char* buf, int n) {
+    FILE* fp = reinterpret_cast<FILE*>(cookie);
+    int ret = TEMP_FAILURE_RETRY(read(fp->_file, buf, n));
+    // If the read succeeded, update the current offset.
+    if (ret >= 0) {
+        fp->_offset += ret;
+    } else {
+        fp->_flags &= ~__SOFF; // Paranoia.
+    }
+    return ret;
+}
+
+int __swrite(void* cookie, const char* buf, int n) {
+    FILE* fp = reinterpret_cast<FILE*>(cookie);
+    if (fp->_flags & __SAPP) {
+        (void) TEMP_FAILURE_RETRY(lseek(fp->_file, 0, SEEK_END));
+    }
+    fp->_flags &= ~__SOFF; // In case FAPPEND mode is set.
+    return TEMP_FAILURE_RETRY(write(fp->_file, buf, n));
+}
+
+// TODO: _FILE_OFFSET_BITS=64.
+fpos_t __sseek(void* cookie, fpos_t offset, int whence) {
+    FILE* fp = reinterpret_cast<FILE*>(cookie);
+    off_t ret = TEMP_FAILURE_RETRY(lseek(fp->_file, offset, whence));
+    if (ret == -1) {
+        fp->_flags &= ~__SOFF;
+    } else {
+        fp->_flags |= __SOFF;
+        fp->_offset = ret;
+    }
+    return ret;
+}
+
+int __sclose(void* cookie) {
+    FILE* fp = reinterpret_cast<FILE*>(cookie);
+    return close(fp->_file);
+}