Re: possible fix for alsa-oss fopen() [Patch]

[Florian Schmidt <mista.tapas@gmx.net>]

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On Fri, 11 Jun 2004 01:27:53 +0200
Florian Schmidt <mista.tapas@gmx.net> wrote:

minor fix [now dsp0, dsp1, etc. should be covered, too.. a little hacky though]

http://www.affenbande.org/~tapas/alsa-oss-1.0.5-artsdsp-rip.tar.bz2
http://www.affenbande.org/~tapas/alsa-oss-fopen.patch

Florian Schmidt


-- 
Palimm Palimm!


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diff -uNr alsa-oss-1.0.5/alsa/alsa-oss.c alsa-oss-1.0.5-artsdsp-rip/alsa/alsa-oss.c
--- alsa-oss-1.0.5/alsa/alsa-oss.c	2004-02-26 19:34:58.000000000 +0100
+++ alsa-oss-1.0.5-artsdsp-rip/alsa/alsa-oss.c	2004-06-11 19:59:36.000000000 +0200
@@ -73,6 +73,8 @@
 void *(*_mmap)(void *addr, size_t len, int prot, int flags, int fd, off_t offset);
 int (*_munmap)(void* addr, size_t len);
 
+FILE *(*_fopen)(const char *path, const char *mode);
+
 typedef struct ops {
 	int (*close)(int fd);
 	ssize_t (*write)(int fd, const void *buf, size_t n);
@@ -630,6 +632,24 @@
 	return count1;
 }
 
+static int is_sound_device(const char *pathname)
+{
+	if(!pathname) return 0;
+	if(strncmp(pathname,"/dev/dsp",8) == 0) return 1;
+	if(strncmp(pathname,"/dev/sound/dsp",14) == 0) return 1;
+	return 0;
+}
+
+
+#include "stdioemu.c"
+
+FILE *fopen(const char* path, const char *mode) {
+	if(!is_sound_device(path)) 
+		return _fopen (path, mode);
+	
+	return fake_fopen(path, mode);
+}
+
 #if 1
 # define strong_alias(name, aliasname) \
   extern __typeof (name) aliasname __attribute__ ((alias (#name)));
@@ -643,6 +663,7 @@
 strong_alias(munmap, __munmap);
 strong_alias(poll, __poll);
 strong_alias(select, __select);
+strong_alias(fopen, __fopen);
 #else
 int dup(int fd)
 {
@@ -712,4 +733,5 @@
 	_munmap = dlsym(RTLD_NEXT, "munmap");
 	_select = dlsym(RTLD_NEXT, "select");
 	_poll = dlsym(RTLD_NEXT, "poll");
+	_fopen = dlsym(RTLD_NEXT, "fopen");
 }
diff -uNr alsa-oss-1.0.5/alsa/stdioemu.c alsa-oss-1.0.5-artsdsp-rip/alsa/stdioemu.c
--- alsa-oss-1.0.5/alsa/stdioemu.c	1970-01-01 01:00:00.000000000 +0100
+++ alsa-oss-1.0.5-artsdsp-rip/alsa/stdioemu.c	2004-06-10 23:56:40.000000000 +0200
@@ -0,0 +1,96 @@
+    /*
+
+    Copyright (C) 2000 Stefan Westerfeld
+                       stefan@space.twc.de
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Library General Public
+    License as published by the Free Software Foundation; either
+    version 2 of the License, or (at your option) any later version.
+  
+    This library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Library General Public License for more details.
+   
+    You should have received a copy of the GNU Library General Public License
+    along with this library; see the file COPYING.LIB.  If not, write to
+    the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+    Boston, MA 02111-1307, USA.
+
+    */
+
+/*
+ * This source only exists because some very special programs think that
+ * it is a very special idea to access /dev/dsp by the means of stdio, so
+ * we need to fake FILE* access for artsdsp as well.
+ *
+ * To do so, it relies on glibc internals, so that it will probably not work
+ * on other systems - but then again, it might not be necessary on other
+ * systems, when fopen properly calls open, it might as well work unchanged.
+ */
+
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#include <stdio.h>
+#include <libio.h>
+
+struct fd_cookie {
+	int fd;
+};
+
+static ssize_t fdc_read (void *cookie, char *buffer, size_t size)
+{
+	struct fd_cookie *fdc = (struct fd_cookie *)cookie;
+	return read(fdc->fd, buffer, size);
+}
+
+static ssize_t fdc_write (void *cookie, const char *buffer, size_t size)
+{
+	struct fd_cookie *fdc = (struct fd_cookie *)cookie;
+	return write(fdc->fd, buffer, size);
+}
+
+static int fdc_seek (void* cookie, off64_t* position, int whence)
+{
+	return -1;
+}
+
+static int fdc_clean (void *cookie)
+{
+	struct fd_cookie *fdc = (struct fd_cookie *)cookie;
+	int result = close(fdc->fd);
+	free(cookie);
+	return result;
+}
+
+static FILE *fake_fopen(const char *path, const char *mode)
+{
+	cookie_io_functions_t fns = { fdc_read, fdc_write, fdc_seek, fdc_clean };
+	struct fd_cookie *fdc =
+		(struct fd_cookie *)malloc(sizeof(struct fd_cookie));
+	const char *mptr;
+	int open_mode = 0;
+	FILE *result = 0;
+
+	for(mptr = mode; *mptr; mptr++)
+	{
+		if(*mptr == 'r') open_mode |= 1; /* 1 = read */
+		if(*mptr == 'w') open_mode |= 2; /* 2 = write */
+		if(*mptr == '+') open_mode |= 3; /* 3 = readwrite */
+		if(*mptr == 'a') open_mode |= 2; /* append -> write */
+  	}
+  	if(open_mode == 1) fdc->fd = open(path,O_RDONLY,0666);
+  	if(open_mode == 2) fdc->fd = open(path,O_WRONLY,0666);
+  	if(open_mode == 3) fdc->fd = open(path,O_RDWR,0666);
+
+	if(open_mode && fdc->fd > 0)
+	{
+		result = fopencookie (fdc,"w", fns);
+		result->_fileno = fdc->fd;		/* ugly patchy slimy kludgy hack */
+	}
+	return result;
+}