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[POWERPC] zImage: Add more flexible gunzip convenience functions
At present, arch/powerpc/boot/main.c includes a gunzip() function which is a convenient wrapper around zlib. However, it doesn't conveniently allow decompressing part of an image to one location, then the remainder to a different address. This patch adds a new set of more flexible convenience wrappers around zlib, moving them to their own file, gunzip_util.c, in the process. These wrappers allow decompressing sections of the compressed image to different locations. In addition, they transparently handle uncompressed data, avoiding special case code to handle uncompressed vmlinux images. The patch also converts main.c to use the new wrappers, using the new flexibility to avoid decompressing the vmlinux's ELF header twice as we did previously. That in turn means we avoid extending our allocations for the vmlinux to allow space for the extra copy of the ELF header. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
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David Gibson
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Paul Mackerras
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Mar 13, 2007
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,140 @@ | ||
| /* | ||
| * Copyright 2007 David Gibson, IBM Corporation. | ||
| * Based on earlier work, Copyright (C) Paul Mackerras 1997. | ||
| * | ||
| * This program is free software; you can redistribute it and/or | ||
| * modify it under the terms of the GNU General Public License | ||
| * as published by the Free Software Foundation; either version | ||
| * 2 of the License, or (at your option) any later version. | ||
| */ | ||
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| #include <stddef.h> | ||
| #include "string.h" | ||
| #include "stdio.h" | ||
| #include "ops.h" | ||
| #include "gunzip_util.h" | ||
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| struct gunzip_state state; | ||
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| #define HEAD_CRC 2 | ||
| #define EXTRA_FIELD 4 | ||
| #define ORIG_NAME 8 | ||
| #define COMMENT 0x10 | ||
| #define RESERVED 0xe0 | ||
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| void gunzip_start(struct gunzip_state *state, void *src, int srclen) | ||
| { | ||
| char *hdr = src; | ||
| int hdrlen = 0; | ||
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| memset(state, 0, sizeof(*state)); | ||
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| /* Check for gzip magic number */ | ||
| if ((hdr[0] == 0x1f) && (hdr[1] == 0x8b)) { | ||
| /* gzip data, initialize zlib parameters */ | ||
| int r, flags; | ||
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| state->s.workspace = state->scratch; | ||
| if (zlib_inflate_workspacesize() > sizeof(state->scratch)) { | ||
| printf("insufficient scratch space for gunzip\n\r"); | ||
| exit(); | ||
| } | ||
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| /* skip header */ | ||
| hdrlen = 10; | ||
| flags = hdr[3]; | ||
| if (hdr[2] != Z_DEFLATED || (flags & RESERVED) != 0) { | ||
| printf("bad gzipped data\n\r"); | ||
| exit(); | ||
| } | ||
| if ((flags & EXTRA_FIELD) != 0) | ||
| hdrlen = 12 + hdr[10] + (hdr[11] << 8); | ||
| if ((flags & ORIG_NAME) != 0) | ||
| while (hdr[hdrlen++] != 0) | ||
| ; | ||
| if ((flags & COMMENT) != 0) | ||
| while (hdr[hdrlen++] != 0) | ||
| ; | ||
| if ((flags & HEAD_CRC) != 0) | ||
| hdrlen += 2; | ||
| if (hdrlen >= srclen) { | ||
| printf("gunzip_start: ran out of data in header\n\r"); | ||
| exit(); | ||
| } | ||
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| r = zlib_inflateInit2(&state->s, -MAX_WBITS); | ||
| if (r != Z_OK) { | ||
| printf("inflateInit2 returned %d\n\r", r); | ||
| exit(); | ||
| } | ||
| } | ||
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| state->s.next_in = src + hdrlen; | ||
| state->s.avail_in = srclen - hdrlen; | ||
| } | ||
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| int gunzip_partial(struct gunzip_state *state, void *dst, int dstlen) | ||
| { | ||
| int len; | ||
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| if (state->s.workspace) { | ||
| /* gunzipping */ | ||
| int r; | ||
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| state->s.next_out = dst; | ||
| state->s.avail_out = dstlen; | ||
| r = zlib_inflate(&state->s, Z_FULL_FLUSH); | ||
| if (r != Z_OK && r != Z_STREAM_END) { | ||
| printf("inflate returned %d msg: %s\n\r", r, state->s.msg); | ||
| exit(); | ||
| } | ||
| len = state->s.next_out - (unsigned char *)dst; | ||
| } else { | ||
| /* uncompressed image */ | ||
| len = min(state->s.avail_in, (unsigned)dstlen); | ||
| memcpy(dst, state->s.next_in, len); | ||
| state->s.next_in += len; | ||
| state->s.avail_in -= len; | ||
| } | ||
| return len; | ||
| } | ||
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| void gunzip_exactly(struct gunzip_state *state, void *dst, int dstlen) | ||
| { | ||
| int len; | ||
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| len = gunzip_partial(state, dst, dstlen); | ||
| if (len < dstlen) { | ||
| printf("gunzip_block: ran out of data\n\r"); | ||
| exit(); | ||
| } | ||
| } | ||
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| void gunzip_discard(struct gunzip_state *state, int len) | ||
| { | ||
| static char discard_buf[128]; | ||
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| while (len > sizeof(discard_buf)) { | ||
| gunzip_exactly(state, discard_buf, sizeof(discard_buf)); | ||
| len -= sizeof(discard_buf); | ||
| } | ||
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| if (len > 0) | ||
| gunzip_exactly(state, discard_buf, len); | ||
| } | ||
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| int gunzip_finish(struct gunzip_state *state, void *dst, int dstlen) | ||
| { | ||
| int len; | ||
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| if (state->s.workspace) { | ||
| len = gunzip_partial(state, dst, dstlen); | ||
| zlib_inflateEnd(&state->s); | ||
| } else { | ||
| /* uncompressed image */ | ||
| len = min(state->s.avail_in, (unsigned)dstlen); | ||
| memcpy(dst, state->s.next_in, len); | ||
| } | ||
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| return len; | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,30 @@ | ||
| /* | ||
| * Decompression convenience functions | ||
| * | ||
| * Copyright 2007 David Gibson, IBM Corporation. | ||
| * | ||
| * This file is licensed under the terms of the GNU General Public | ||
| * License version 2. This program is licensed "as is" without any | ||
| * warranty of any kind, whether express or implied. | ||
| */ | ||
| #ifndef _PPC_BOOT_GUNZIP_UTIL_H_ | ||
| #define _PPC_BOOT_GUNZIP_UTIL_H_ | ||
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| #include "zlib.h" | ||
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| /* scratch space for gunzip; 46912 is from zlib_inflate_workspacesize() */ | ||
| #define GUNZIP_SCRATCH_SIZE 46912 | ||
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| struct gunzip_state { | ||
| z_stream s; | ||
| char scratch[46912]; | ||
| }; | ||
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| void gunzip_start(struct gunzip_state *state, void *src, int srclen); | ||
| int gunzip_partial(struct gunzip_state *state, void *dst, int dstlen); | ||
| void gunzip_exactly(struct gunzip_state *state, void *dst, int len); | ||
| void gunzip_discard(struct gunzip_state *state, int len); | ||
| int gunzip_finish(struct gunzip_state *state, void *dst, int len); | ||
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| #endif /* _PPC_BOOT_GUNZIP_UTIL_H_ */ | ||
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