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authorH. Peter Anvin <hpa@zytor.com>2009-07-09 11:56:17 -0700
committerH. Peter Anvin <hpa@zytor.com>2009-07-09 11:56:17 -0700
commit60f2833c31a57a0a8cc69a0ee6e20692d0cc5157 (patch)
tree69b0d53f6917d8195c2541807137e8efefa60a58
parent0b4b1529f14037c5a4d61cf90b010464170b6d2a (diff)
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Add openmem() function to read from memory as if it were a file
Reading from memory as if it were a file is pretty easy... we just treat it as a really big block buffer and tell the file layer that we already closed the underlying handle. Signed-off-by: H. Peter Anvin <hpa@zytor.com>
-rw-r--r--com32/include/dev.h1
-rw-r--r--com32/lib/sys/file.h12
-rw-r--r--com32/lib/sys/open.c6
-rw-r--r--com32/lib/sys/openmem.c60
4 files changed, 70 insertions, 9 deletions
diff --git a/com32/include/dev.h b/com32/include/dev.h
index 7809fb56..70b3165c 100644
--- a/com32/include/dev.h
+++ b/com32/include/dev.h
@@ -41,6 +41,7 @@ struct input_dev;
struct output_dev;
__extern int opendev(const struct input_dev *, const struct output_dev *, int);
+__extern int openmem(const void *, size_t, int);
/* Common generic devices */
diff --git a/com32/lib/sys/file.h b/com32/lib/sys/file.h
index fff91b19..66192fbf 100644
--- a/com32/lib/sys/file.h
+++ b/com32/lib/sys/file.h
@@ -56,18 +56,18 @@ struct input_dev {
uint16_t dev_magic; /* Magic number */
uint16_t flags; /* Flags */
int fileflags; /* Permitted file flags */
- ssize_t(*read) (struct file_info *, void *, size_t);
- int (*close) (struct file_info *);
- int (*open) (struct file_info *);
+ ssize_t (*read)(struct file_info *, void *, size_t);
+ int (*close)(struct file_info *);
+ int (*open)(struct file_info *);
};
struct output_dev {
uint16_t dev_magic; /* Magic number */
uint16_t flags; /* Flags */
int fileflags;
- ssize_t(*write) (struct file_info *, const void *, size_t);
- int (*close) (struct file_info *);
- int (*open) (struct file_info *);
+ ssize_t (*write)(struct file_info *, const void *, size_t);
+ int (*close)(struct file_info *);
+ int (*open)(struct file_info *);
const struct output_dev *fallback; /* Fallback option for certain consoles */
};
diff --git a/com32/lib/sys/open.c b/com32/lib/sys/open.c
index aabbec21..114728ec 100644
--- a/com32/lib/sys/open.c
+++ b/com32/lib/sys/open.c
@@ -41,7 +41,7 @@
extern ssize_t __file_read(struct file_info *, void *, size_t);
extern int __file_close(struct file_info *);
-static const struct input_dev file_dev = {
+const struct input_dev __file_dev = {
.dev_magic = __DEV_MAGIC,
.flags = __DEV_FILE | __DEV_INPUT,
.fileflags = O_RDONLY,
@@ -56,7 +56,7 @@ int open(const char *pathname, int flags, ...)
int fd;
struct file_info *fp;
- fd = opendev(&file_dev, NULL, flags);
+ fd = opendev(&__file_dev, NULL, flags);
if (fd < 0)
return -1;
@@ -78,7 +78,7 @@ int open(const char *pathname, int flags, ...)
{
uint16_t blklg2;
-asm("bsrw %1,%0": "=r"(blklg2):"rm"(regs.ecx.w[0]));
+ asm("bsrw %1,%0" : "=r"(blklg2) : "rm"(regs.ecx.w[0]));
fp->i.blocklg2 = blklg2;
}
fp->i.length = regs.eax.l;
diff --git a/com32/lib/sys/openmem.c b/com32/lib/sys/openmem.c
new file mode 100644
index 00000000..13a45c2a
--- /dev/null
+++ b/com32/lib/sys/openmem.c
@@ -0,0 +1,60 @@
+/* ----------------------------------------------------------------------- *
+ *
+ * Copyright 2003-2008 H. Peter Anvin - All Rights Reserved
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom
+ * the Software is furnished to do so, subject to the following
+ * conditions:
+ *
+ * The above copyright notice and this permission notice shall
+ * be included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * ----------------------------------------------------------------------- */
+
+#include <errno.h>
+#include <com32.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include "file.h"
+
+/*
+ * openmem.c
+ *
+ * Open a chunk of memory as if it was a file
+ */
+
+const struct input_dev __file_dev;
+
+int openmem(const void *base, size_t len, int flags)
+{
+ com32sys_t regs;
+ int fd;
+ struct file_info *fp;
+
+ fd = opendev(&__file_dev, NULL, flags);
+
+ if (fd < 0)
+ return -1;
+
+ fp->i.length = fp->i.nbytes = len;
+ fp->i.datap = (void *)base;
+ fp->i.filedes = 0; /* No actual file */
+ fp->i.offset = 0;
+
+ return fd;
+}