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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 | // SPDX-License-Identifier: GPL-2.0-only /* * Copyright (c) 2013, 2014 * Phillip Lougher <phillip@squashfs.org.uk> */ #include <linux/bio.h> #include <linux/mutex.h> #include <linux/slab.h> #include <linux/vmalloc.h> #include <linux/lz4.h> #include "squashfs_fs.h" #include "squashfs_fs_sb.h" #include "squashfs.h" #include "decompressor.h" #include "page_actor.h" #define LZ4_LEGACY 1 struct lz4_comp_opts { __le32 version; __le32 flags; }; struct squashfs_lz4 { void *input; void *output; }; static void *lz4_comp_opts(struct squashfs_sb_info *msblk, void *buff, int len) { struct lz4_comp_opts *comp_opts = buff; /* LZ4 compressed filesystems always have compression options */ if (comp_opts == NULL || len < sizeof(*comp_opts)) return ERR_PTR(-EIO); if (le32_to_cpu(comp_opts->version) != LZ4_LEGACY) { /* LZ4 format currently used by the kernel is the 'legacy' * format */ ERROR("Unknown LZ4 version\n"); return ERR_PTR(-EINVAL); } return NULL; } static void *lz4_init(struct squashfs_sb_info *msblk, void *buff) { int block_size = max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE); struct squashfs_lz4 *stream; stream = kzalloc(sizeof(*stream), GFP_KERNEL); if (stream == NULL) goto failed; stream->input = vmalloc(block_size); if (stream->input == NULL) goto failed2; stream->output = vmalloc(block_size); if (stream->output == NULL) goto failed3; return stream; failed3: vfree(stream->input); failed2: kfree(stream); failed: ERROR("Failed to initialise LZ4 decompressor\n"); return ERR_PTR(-ENOMEM); } static void lz4_free(void *strm) { struct squashfs_lz4 *stream = strm; if (stream) { vfree(stream->input); vfree(stream->output); } kfree(stream); } static int lz4_uncompress(struct squashfs_sb_info *msblk, void *strm, struct bio *bio, int offset, int length, struct squashfs_page_actor *output) { struct bvec_iter_all iter_all = {}; struct bio_vec *bvec = bvec_init_iter_all(&iter_all); struct squashfs_lz4 *stream = strm; void *buff = stream->input, *data; int bytes = length, res; while (bio_next_segment(bio, &iter_all)) { int avail = min(bytes, ((int)bvec->bv_len) - offset); data = bvec_virt(bvec); memcpy(buff, data + offset, avail); buff += avail; bytes -= avail; offset = 0; } res = LZ4_decompress_safe(stream->input, stream->output, length, output->length); if (res < 0) return -EIO; bytes = res; data = squashfs_first_page(output); buff = stream->output; while (data) { if (bytes <= PAGE_SIZE) { if (!IS_ERR(data)) memcpy(data, buff, bytes); break; } if (!IS_ERR(data)) memcpy(data, buff, PAGE_SIZE); buff += PAGE_SIZE; bytes -= PAGE_SIZE; data = squashfs_next_page(output); } squashfs_finish_page(output); return res; } const struct squashfs_decompressor squashfs_lz4_comp_ops = { .init = lz4_init, .comp_opts = lz4_comp_opts, .free = lz4_free, .decompress = lz4_uncompress, .id = LZ4_COMPRESSION, .name = "lz4", .alloc_buffer = 0, .supported = 1 }; |