[PATCH] add support for loading lzma compressed kernels
Simon Horman
horms at verge.net.au
Mon Nov 16 22:04:38 EST 2009
On Mon, Nov 16, 2009 at 12:53:06AM +0100, Florian Fainelli wrote:
> Hi Eric,
>
> This patch allows one to load a lzma compressed kernel using kexec -l.
> As I wanted the lzma code to be very similar to the existing
> zlib slurp_decompress I took lzread and associated routines
> from the cpio lzma support. Tested on my x86 laptop using the
> following commands:
>
> lzma e bzImage bzImage.lzma
> kexec -l bzImage.lzma
>
> Having lzma support is particularly useful on some embedded
> systems on which we have the kernel already lzma compressed
> and available on a mtd partition.
>
> Signed-off-by: Florian Fainelli <florian at openwrt.org>
> --
> diff -urN kexec-tools-2.0.1/configure.ac kexec-tools-2.0.1.lzma/configure.ac
> --- kexec-tools-2.0.1/configure.ac 2009-08-13 01:28:04.000000000 +0200
> +++ kexec-tools-2.0.1.lzma/configure.ac 2009-11-16 00:30:42.000000000 +0100
> @@ -79,6 +79,9 @@
> AC_ARG_WITH([zlib], AC_HELP_STRING([--without-zlib],[disable zlib support]),
> [ with_zlib="$withval"], [ with_zlib=yes ] )
>
> +AC_ARG_WITH([lzma], AC_HELP_STRING([--without-lzma],[disable lzma support]),
> + [ with_lzma="$withval"], [ with_lzma=yes ] )
> +
> AC_ARG_WITH([xen], AC_HELP_STRING([--without-xen],
> [disable extended xen support]), [ with_xen="$withval"], [ with_xen=yes ] )
>
> @@ -142,6 +145,12 @@
> AC_MSG_NOTICE([zlib support disabled])))
> fi
>
> +dnl See if I have a usable copy of lzma available
> +if test "$with_lzma" = yes ; then
> + AC_CHECK_HEADER(lzma.h,
> + AC_CHECK_LIB(lzma, lzma_code_, ,
Should lzma_code_ be lzma_code. The former doesn't seem to work with
liblzma 4.999.9beta+20091016-1 from Debian.
> + AC_MSG_NOTICE([lzma support disabled])))
The trailing "fi" line appears to be missing.
> +
> dnl find Xen control stack libraries
> if test "$with_xen" = yes ; then
> AC_CHECK_HEADER(xenctrl.h,
> diff -urN kexec-tools-2.0.1/include/kexec_lzma.h kexec-tools-2.0.1.lzma/include/kexec_lzma.h
> --- kexec-tools-2.0.1/include/kexec_lzma.h 1970-01-01 01:00:00.000000000 +0100
> +++ kexec-tools-2.0.1.lzma/include/kexec_lzma.h 2009-11-16 00:45:23.000000000 +0100
> @@ -0,0 +1,24 @@
> +#ifndef __KEXEC_LZMA_H
> +#define __KEXEC_LZMA_H
> +
> +#include <sys/types.h>
> +#include <stdio.h>
> +#include <unistd.h>
> +#include <inttypes.h>
> +#include <lzma.h>
> +
> +#define kBufferSize (1 << 15)
> +
> +typedef struct lzfile {
> + uint8_t buf[kBufferSize];
> + lzma_stream strm;
> + FILE *file;
> + int encoding;
> + int eof;
> +} LZFILE;
> +
> +LZFILE *lzopen(const char *path, const char *mode);
> +int lzclose(LZFILE *lzfile);
> +ssize_t lzread(LZFILE *lzfile, void *buf, size_t len);
> +
> +#endif /* __KEXEC_LZMA_H */
> Files kexec-tools-2.0.1/kexec/.kexec.c.swo and kexec-tools-2.0.1.lzma/kexec/.kexec.c.swo differ
> diff -urN kexec-tools-2.0.1/kexec/Makefile kexec-tools-2.0.1.lzma/kexec/Makefile
> --- kexec-tools-2.0.1/kexec/Makefile 2008-10-09 00:32:14.000000000 +0200
> +++ kexec-tools-2.0.1.lzma/kexec/Makefile 2009-11-15 20:36:37.000000000 +0100
> @@ -22,6 +22,7 @@
> KEXEC_SRCS += kexec/crashdump.c
> KEXEC_SRCS += kexec/crashdump-xen.c
> KEXEC_SRCS += kexec/phys_arch.c
> +KEXEC_SRCS += kexec/lzma.c
>
> KEXEC_GENERATED_SRCS += $(PURGATORY_HEX_C)
>
> diff -urN kexec-tools-2.0.1/kexec/kexec.c kexec-tools-2.0.1.lzma/kexec/kexec.c
> --- kexec-tools-2.0.1/kexec/kexec.c 2009-03-18 09:38:55.000000000 +0100
> +++ kexec-tools-2.0.1.lzma/kexec/kexec.c 2009-11-16 00:50:37.000000000 +0100
> @@ -41,6 +41,9 @@
> #ifdef HAVE_LIBZ
> #include <zlib.h>
> #endif
> +#ifdef HAVE_LIBLZMA
> +#include <kexec_lzma.h>
> +#endif
> #include <sha256.h>
> #include "kexec.h"
> #include "kexec-syscall.h"
> @@ -609,6 +612,47 @@
> *r_size = size;
> return buf;
> }
> +#elif defined (HAVE_LIBLZMA)
> +char *slurp_decompress_file(const char *filename, off_t *r_size)
Does this imply that zlib compression isn't supported if
lzma compression support is enabled?
> +{
> + LZFILE *fp;
> + char *buf;
> + off_t size, allocated;
> + ssize_t result;
> +
> + if (!filename) {
> + *r_size = 0;
> + return 0;
> + }
> + fp = lzopen(filename, "rb");
> + if (fp == 0) {
> + die("Cannot open `%s': %s\n", filename);
> + }
> + size = 0;
> + allocated = 65536;
> + buf = xmalloc(allocated);
> + do {
> + if (size == allocated) {
> + allocated <<= 1;
> + buf = xrealloc(buf, allocated);
> + }
> + result = lzread(fp, buf + size, allocated - size);
> + if (result < 0) {
> + if ((errno == EINTR) || (errno == EAGAIN))
> + continue;
> +
> + die ("read on %s of %ld bytes failed\n",
> + filename, (allocated - size) + 0UL);
> + }
> + size += result;
> + } while(result > 0);
> + result = lzclose(fp);
> + if (result != LZMA_OK) {
> + die ("Close of %s failed\n", filename);
> + }
> + *r_size = size;
> + return buf;
> +}
> #else
> char *slurp_decompress_file(const char *filename, off_t *r_size)
> {
> diff -urN kexec-tools-2.0.1/kexec/lzma.c kexec-tools-2.0.1.lzma/kexec/lzma.c
> --- kexec-tools-2.0.1/kexec/lzma.c 1970-01-01 01:00:00.000000000 +0100
> +++ kexec-tools-2.0.1.lzma/kexec/lzma.c 2009-11-16 00:44:56.000000000 +0100
> @@ -0,0 +1,132 @@
> +#include <sys/types.h>
> +#include <inttypes.h>
> +#include <string.h>
> +#include <stdlib.h>
> +#include <lzma.h>
> +#include <kexec_lzma.h>
> +
> +#ifdef HAVE_LIBLZMA
#include <kexec_lzma.h> needs to be inside HAVE_LIBLZMA,
it seems just as well to move the #ifdef to the top of the file.
> +static LZFILE *lzopen_internal(const char *path, const char *mode, int fd)
> +{
> + int level = 5;
> + int encoding = 0;
> + FILE *fp;
> + LZFILE *lzfile;
> + lzma_ret ret;
> + lzma_stream lzma_strm_tmp = LZMA_STREAM_INIT;
> +
> + for (; *mode; mode++) {
> + if (*mode == 'w')
> + encoding = 1;
> + else if (*mode == 'r')
> + encoding = 0;
> + else if (*mode >= '1' && *mode <= '9')
> + level = *mode - '0';
> + }
> + if (fd != -1)
> + fp = fdopen(fd, encoding ? "w" : "r");
> + else
> + fp = fopen(path, encoding ? "w" : "r");
> + if (!fp)
> + return NULL;
> +
> + lzfile = calloc(1, sizeof(*lzfile));
> +
> + if (!lzfile) {
> + fclose(fp);
> + return NULL;
> + }
> +
> + lzfile->file = fp;
> + lzfile->encoding = encoding;
> + lzfile->eof = 0;
> + lzfile->strm = lzma_strm_tmp;
> + if (encoding) {
> + lzma_options_lzma opt_lzma;
> + if (lzma_lzma_preset(&opt_lzma, level - 1))
> + return NULL;
> + ret = lzma_alone_encoder(&lzfile->strm, &opt_lzma);
> + } else {
> + ret = lzma_auto_decoder(&lzfile->strm,
> + UINT64_C(64) * 1024 * 1024, 0);
> + }
> + if (ret != LZMA_OK) {
> + fclose(fp);
> + free(lzfile);
> + return NULL;
> + }
> + return lzfile;
> +}
> +
> +LZFILE *lzopen(const char *path, const char *mode)
> +{
> + return lzopen_internal(path, mode, -1);
> +}
> +
> +int lzclose(LZFILE *lzfile)
> +{
> + lzma_ret ret;
> + int n;
> +
> + if (!lzfile)
> + return -1;
> +
> + if (lzfile->encoding) {
> + for (;;) {
> + lzfile->strm.avail_out = kBufferSize;
> + lzfile->strm.next_out = lzfile->buf;
> + ret = lzma_code(&lzfile->strm, LZMA_FINISH);
> + if (ret != LZMA_OK && ret != LZMA_STREAM_END)
> + return -1;
> + n = kBufferSize - lzfile->strm.avail_out;
> + if (n && fwrite(lzfile->buf, 1, n, lzfile->file) != n)
> + return -1;
> + if (ret == LZMA_STREAM_END)
> + break;
> + }
> + }
> + lzma_end(&lzfile->strm);
> +
> + return fclose(lzfile->file);
> + free(lzfile);
> +}
> +
> +ssize_t lzread(LZFILE *lzfile, void *buf, size_t len)
> +{
> + lzma_ret ret;
> + int eof = 0;
> +
> + if (!lzfile || lzfile->encoding)
> + return -1;
> +
> + if (lzfile->eof)
> + return 0;
> +
> + lzfile->strm.next_out = buf;
> + lzfile->strm.avail_out = len;
> +
> + for (;;) {
> + if (!lzfile->strm.avail_in) {
> + lzfile->strm.next_in = lzfile->buf;
> + lzfile->strm.avail_in = fread(lzfile->buf, 1, kBufferSize, lzfile->file);
> + if (!lzfile->strm.avail_in)
> + eof = 1;
> + }
> +
> + ret = lzma_code(&lzfile->strm, LZMA_RUN);
> + if (ret == LZMA_STREAM_END) {
> + lzfile->eof = 1;
> + return len - lzfile->strm.avail_out;
> + }
> +
> + if (ret != LZMA_OK)
> + return -1;
> +
> + if (!lzfile->strm.avail_out)
> + return len;
> +
> + if (eof)
> + return -1;
> + }
> +}
> +#endif /* HAVE_LIBLZMA */
>
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