bzip2/lzma: config and initramfs support for bzip2/lzma decompression

Impact: New code for initramfs decompression, new features

This is the second part of the bzip2/lzma patch

The bzip patch is based on an idea by Christian Ludwig, includes support for
compressing the kernel with bzip2 or lzma rather than gzip. Both
compressors give smaller sizes than gzip.  Lzma's decompresses faster
than bzip2.

It also supports ramdisks and initramfs' compressed using these two
compressors.

The functionality has been successfully used for a couple of years by
the udpcast project

This version applies to "tip" kernel 2.6.28

This part contains:
- support for new compressions (bzip2 and lzma) in initramfs and
old-style ramdisk
- config dialog for kernel compression (but new kernel compressions
not yet supported)

Signed-off-by: Alain Knaff <alain@knaff.lu>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 42 insertions, 81 deletions

diff --git a/init/initramfs.c b/init/initramfs.c
index 4f5ba75aaa7..40bd4fb9578 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -389,11 +389,14 @@ static int __init write_buffer(char *buf, unsigned len)
 	return len - count;
 }
 
-static void __init flush_buffer(char *buf, unsigned len)
+
+static int __init flush_buffer(void *bufv, unsigned len)
 {
+	char *buf = (char *) bufv;
 	int written;
+	int origLen = len;
 	if (message)
-		return;
+		return -1;
 	while ((written = write_buffer(buf, len)) < len && !message) {
 		char c = buf[written];
 		if (c == '0') {
@@ -407,73 +410,14 @@ static void __init flush_buffer(char *buf, unsigned len)
 		} else
 			error("junk in compressed archive");
 	}
+	return origLen;
 }
 
-/*
- * gzip declarations
- */
-
-#define OF(args)  args
-
-#ifndef memzero
-#define memzero(s, n)     memset ((s), 0, (n))
-#endif
-
-typedef unsigned char  uch;
-typedef unsigned short ush;
-typedef unsigned long  ulg;
-
-#define WSIZE 0x8000    /* window size--must be a power of two, and */
-			/*  at least 32K for zip's deflate method */
-
-static uch *inbuf;
-static uch *window;
-
-static unsigned insize;  /* valid bytes in inbuf */
-static unsigned inptr;   /* index of next byte to be processed in inbuf */
-static unsigned outcnt;  /* bytes in output buffer */
-static long bytes_out;
-
-#define get_byte()  (inptr < insize ? inbuf[inptr++] : -1)
-		
-/* Diagnostic functions (stubbed out) */
-#define Assert(cond,msg)
-#define Trace(x)
-#define Tracev(x)
-#define Tracevv(x)
-#define Tracec(c,x)
-#define Tracecv(c,x)
-
-#define STATIC static
-#define INIT __init
-
-static void __init flush_window(void);
-static void __init error(char *m);
-
-#define NO_INFLATE_MALLOC
+static unsigned my_inptr;   /* index of next byte to be processed in inbuf */
 
-#include "../lib/inflate.c"
-
-/* ===========================================================================
- * Write the output window window[0..outcnt-1] and update crc and bytes_out.
- * (Used for the decompressed data only.)
- */
-static void __init flush_window(void)
-{
-	ulg c = crc;         /* temporary variable */
-	unsigned n;
-	uch *in, ch;
-
-	flush_buffer(window, outcnt);
-	in = window;
-	for (n = 0; n < outcnt; n++) {
-		ch = *in++;
-		c = crc_32_tab[((int)c ^ ch) & 0xff] ^ (c >> 8);
-	}
-	crc = c;
-	bytes_out += (ulg)outcnt;
-	outcnt = 0;
-}
+#include <linux/decompress/bunzip2.h>
+#include <linux/decompress/unlzma.h>
+#include <linux/decompress/inflate.h>
 
 static char * __init unpack_to_rootfs(char *buf, unsigned len, int check_only)
 {
@@ -482,9 +426,10 @@ static char * __init unpack_to_rootfs(char *buf, unsigned len, int check_only)
 	header_buf = kmalloc(110, GFP_KERNEL);
 	symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL);
 	name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);
-	window = kmalloc(WSIZE, GFP_KERNEL);
-	if (!window || !header_buf || !symlink_buf || !name_buf)
+
+	if (!header_buf || !symlink_buf || !name_buf)
 		panic("can't allocate buffers");
+
 	state = Start;
 	this_header = 0;
 	message = NULL;
@@ -504,22 +449,38 @@ static char * __init unpack_to_rootfs(char *buf, unsigned len, int check_only)
 			continue;
 		}
 		this_header = 0;
-		insize = len;
-		inbuf = buf;
-		inptr = 0;
-		outcnt = 0;		/* bytes in output buffer */
-		bytes_out = 0;
-		crc = (ulg)0xffffffffL; /* shift register contents */
-		makecrc();
-		gunzip();
+		if (!gunzip(buf, len, NULL, flush_buffer, NULL,
+			    &my_inptr, error) &&
+		    message == NULL)
+			goto ok;
+
+#ifdef CONFIG_RD_BZIP2
+		message = NULL; /* Zero out message, or else cpio will
+				   think an error has already occured */
+		if (!bunzip2(buf, len, NULL, flush_buffer, NULL,
+			     &my_inptr, error) &&
+		    message == NULL) {
+			goto ok;
+		}
+#endif
+
+#ifdef CONFIG_RD_LZMA
+		message = NULL; /* Zero out message, or else cpio will
+				   think an error has already occured */
+		if (!unlzma(buf, len, NULL, flush_buffer, NULL,
+			    &my_inptr, error) &&
+		    message == NULL) {
+			goto ok;
+		}
+#endif
+ok:
 		if (state != Reset)
-			error("junk in gzipped archive");
-		this_header = saved_offset + inptr;
-		buf += inptr;
-		len -= inptr;
+			error("junk in compressed archive");
+		this_header = saved_offset + my_inptr;
+		buf += my_inptr;
+		len -= my_inptr;
 	}
 	dir_utime();
-	kfree(window);
 	kfree(name_buf);
 	kfree(symlink_buf);
 	kfree(header_buf);