| 1 | |
| 2 | #include <fcntl.h>
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| 3 | #include <stdio.h>
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| 4 | #include <string.h>
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| 5 | #include <unistd.h>
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| 6 | #include <sys/stat.h>
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| 7 | #include <sys/mman.h>
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| 8 | #include <zlib.h>
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| 9 | #include <linux/compiler.h>
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| 10 | #include <internal/lib.h>
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| 11 |
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| 12 | #include "util/compress.h"
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| 13 |
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| 14 | #define CHUNK_SIZE 16384
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| 15 |
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| 16 | int gzip_decompress_to_file(const char *input, int output_fd)
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| 17 | {
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| 18 | int ret = Z_STREAM_ERROR;
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| 19 | int input_fd;
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| 20 | void *ptr;
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| 21 | int len;
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| 22 | struct stat stbuf;
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| 23 | unsigned char buf[CHUNK_SIZE];
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| 24 | z_stream zs = {
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| 25 | .zalloc = Z_NULL,
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| 26 | .zfree = Z_NULL,
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| 27 | .opaque = Z_NULL,
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| 28 | .avail_in = 0,
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| 29 | .next_in = Z_NULL,
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| 30 | };
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| 31 |
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| 32 | input_fd = open(input, O_RDONLY);
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| 33 | if (input_fd < 0)
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| 34 | return -1;
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| 35 |
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| 36 | if (fstat(input_fd, &stbuf) < 0)
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| 37 | goto out_close;
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| 38 |
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| 39 | ptr = mmap(NULL, stbuf.st_size, PROT_READ, MAP_PRIVATE, input_fd, 0);
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| 40 | if (ptr == MAP_FAILED)
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| 41 | goto out_close;
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| 42 |
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| 43 | if (inflateInit2(&zs, 16 + MAX_WBITS) != Z_OK)
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| 44 | goto out_unmap;
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| 45 |
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| 46 | zs.next_in = ptr;
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| 47 | zs.avail_in = stbuf.st_size;
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| 48 |
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| 49 | do {
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| 50 | zs.next_out = buf;
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| 51 | zs.avail_out = CHUNK_SIZE;
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| 52 |
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| 53 | ret = inflate(&zs, Z_NO_FLUSH);
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| 54 | switch (ret) {
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| 55 | case Z_NEED_DICT:
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| 56 | ret = Z_DATA_ERROR;
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| 57 |
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| 58 | case Z_DATA_ERROR:
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| 59 | case Z_MEM_ERROR:
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| 60 | goto out;
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| 61 | default:
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| 62 | break;
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| 63 | }
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| 64 |
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| 65 | len = CHUNK_SIZE - zs.avail_out;
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| 66 | if (writen(output_fd, buf, len) != len) {
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| 67 | ret = Z_DATA_ERROR;
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| 68 | goto out;
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| 69 | }
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| 70 |
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| 71 | } while (ret != Z_STREAM_END);
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| 72 |
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| 73 | out:
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| 74 | inflateEnd(&zs);
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| 75 | out_unmap:
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| 76 | munmap(ptr, stbuf.st_size);
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| 77 | out_close:
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| 78 | close(input_fd);
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| 79 |
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| 80 | return ret == Z_STREAM_END ? 0 : -1;
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| 81 | }
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| 82 |
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| 83 | bool gzip_is_compressed(const char *input)
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| 84 | {
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| 85 | int fd = open(input, O_RDONLY);
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| 86 | const uint8_t magic[2] = { 0x1f, 0x8b };
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| 87 | char buf[2] = { 0 };
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| 88 | ssize_t rc;
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| 89 |
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| 90 | if (fd < 0)
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| 91 | return false;
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| 92 |
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| 93 | rc = read(fd, buf, sizeof(buf));
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| 94 | close(fd);
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| 95 | return rc == sizeof(buf) ?
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| 96 | memcmp(buf, magic, sizeof(buf)) == 0 : false;
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| 97 | }
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