1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun #include <fcntl.h>
3*4882a593Smuzhiyun #include <stdio.h>
4*4882a593Smuzhiyun #include <string.h>
5*4882a593Smuzhiyun #include <unistd.h>
6*4882a593Smuzhiyun #include <sys/stat.h>
7*4882a593Smuzhiyun #include <sys/mman.h>
8*4882a593Smuzhiyun #include <zlib.h>
9*4882a593Smuzhiyun #include <linux/compiler.h>
10*4882a593Smuzhiyun #include <internal/lib.h>
11*4882a593Smuzhiyun
12*4882a593Smuzhiyun #include "util/compress.h"
13*4882a593Smuzhiyun
14*4882a593Smuzhiyun #define CHUNK_SIZE 16384
15*4882a593Smuzhiyun
gzip_decompress_to_file(const char * input,int output_fd)16*4882a593Smuzhiyun int gzip_decompress_to_file(const char *input, int output_fd)
17*4882a593Smuzhiyun {
18*4882a593Smuzhiyun int ret = Z_STREAM_ERROR;
19*4882a593Smuzhiyun int input_fd;
20*4882a593Smuzhiyun void *ptr;
21*4882a593Smuzhiyun int len;
22*4882a593Smuzhiyun struct stat stbuf;
23*4882a593Smuzhiyun unsigned char buf[CHUNK_SIZE];
24*4882a593Smuzhiyun z_stream zs = {
25*4882a593Smuzhiyun .zalloc = Z_NULL,
26*4882a593Smuzhiyun .zfree = Z_NULL,
27*4882a593Smuzhiyun .opaque = Z_NULL,
28*4882a593Smuzhiyun .avail_in = 0,
29*4882a593Smuzhiyun .next_in = Z_NULL,
30*4882a593Smuzhiyun };
31*4882a593Smuzhiyun
32*4882a593Smuzhiyun input_fd = open(input, O_RDONLY);
33*4882a593Smuzhiyun if (input_fd < 0)
34*4882a593Smuzhiyun return -1;
35*4882a593Smuzhiyun
36*4882a593Smuzhiyun if (fstat(input_fd, &stbuf) < 0)
37*4882a593Smuzhiyun goto out_close;
38*4882a593Smuzhiyun
39*4882a593Smuzhiyun ptr = mmap(NULL, stbuf.st_size, PROT_READ, MAP_PRIVATE, input_fd, 0);
40*4882a593Smuzhiyun if (ptr == MAP_FAILED)
41*4882a593Smuzhiyun goto out_close;
42*4882a593Smuzhiyun
43*4882a593Smuzhiyun if (inflateInit2(&zs, 16 + MAX_WBITS) != Z_OK)
44*4882a593Smuzhiyun goto out_unmap;
45*4882a593Smuzhiyun
46*4882a593Smuzhiyun zs.next_in = ptr;
47*4882a593Smuzhiyun zs.avail_in = stbuf.st_size;
48*4882a593Smuzhiyun
49*4882a593Smuzhiyun do {
50*4882a593Smuzhiyun zs.next_out = buf;
51*4882a593Smuzhiyun zs.avail_out = CHUNK_SIZE;
52*4882a593Smuzhiyun
53*4882a593Smuzhiyun ret = inflate(&zs, Z_NO_FLUSH);
54*4882a593Smuzhiyun switch (ret) {
55*4882a593Smuzhiyun case Z_NEED_DICT:
56*4882a593Smuzhiyun ret = Z_DATA_ERROR;
57*4882a593Smuzhiyun /* fall through */
58*4882a593Smuzhiyun case Z_DATA_ERROR:
59*4882a593Smuzhiyun case Z_MEM_ERROR:
60*4882a593Smuzhiyun goto out;
61*4882a593Smuzhiyun default:
62*4882a593Smuzhiyun break;
63*4882a593Smuzhiyun }
64*4882a593Smuzhiyun
65*4882a593Smuzhiyun len = CHUNK_SIZE - zs.avail_out;
66*4882a593Smuzhiyun if (writen(output_fd, buf, len) != len) {
67*4882a593Smuzhiyun ret = Z_DATA_ERROR;
68*4882a593Smuzhiyun goto out;
69*4882a593Smuzhiyun }
70*4882a593Smuzhiyun
71*4882a593Smuzhiyun } while (ret != Z_STREAM_END);
72*4882a593Smuzhiyun
73*4882a593Smuzhiyun out:
74*4882a593Smuzhiyun inflateEnd(&zs);
75*4882a593Smuzhiyun out_unmap:
76*4882a593Smuzhiyun munmap(ptr, stbuf.st_size);
77*4882a593Smuzhiyun out_close:
78*4882a593Smuzhiyun close(input_fd);
79*4882a593Smuzhiyun
80*4882a593Smuzhiyun return ret == Z_STREAM_END ? 0 : -1;
81*4882a593Smuzhiyun }
82*4882a593Smuzhiyun
gzip_is_compressed(const char * input)83*4882a593Smuzhiyun bool gzip_is_compressed(const char *input)
84*4882a593Smuzhiyun {
85*4882a593Smuzhiyun int fd = open(input, O_RDONLY);
86*4882a593Smuzhiyun const uint8_t magic[2] = { 0x1f, 0x8b };
87*4882a593Smuzhiyun char buf[2] = { 0 };
88*4882a593Smuzhiyun ssize_t rc;
89*4882a593Smuzhiyun
90*4882a593Smuzhiyun if (fd < 0)
91*4882a593Smuzhiyun return -1;
92*4882a593Smuzhiyun
93*4882a593Smuzhiyun rc = read(fd, buf, sizeof(buf));
94*4882a593Smuzhiyun close(fd);
95*4882a593Smuzhiyun return rc == sizeof(buf) ?
96*4882a593Smuzhiyun memcmp(buf, magic, sizeof(buf)) == 0 : false;
97*4882a593Smuzhiyun }
98