1// SPDX-License-Identifier: GPL-2.0
  2#include <errno.h>
  3#include <lzma.h>
  4#include <stdio.h>
  5#include <linux/compiler.h>
  6#include <sys/types.h>
  7#include <sys/stat.h>
  8#include <fcntl.h>
  9#include "compress.h"
 10#include "debug.h"
 11#include <string.h>
 12#include <unistd.h>
 13#include <internal/lib.h>
 14
 15#define BUFSIZE 8192
 16
 17static const char *lzma_strerror(lzma_ret ret)
 18{
 19	switch ((int) ret) {
 20	case LZMA_MEM_ERROR:
 21		return "Memory allocation failed";
 22	case LZMA_OPTIONS_ERROR:
 23		return "Unsupported decompressor flags";
 24	case LZMA_FORMAT_ERROR:
 25		return "The input is not in the .xz format";
 26	case LZMA_DATA_ERROR:
 27		return "Compressed file is corrupt";
 28	case LZMA_BUF_ERROR:
 29		return "Compressed file is truncated or otherwise corrupt";
 30	default:
 31		return "Unknown error, possibly a bug";
 32	}
 33}
 34
 35int lzma_decompress_to_file(const char *input, int output_fd)
 36{
 37	lzma_action action = LZMA_RUN;
 38	lzma_stream strm   = LZMA_STREAM_INIT;
 39	lzma_ret ret;
 40	int err = -1;
 41
 42	u8 buf_in[BUFSIZE];
 43	u8 buf_out[BUFSIZE];
 44	FILE *infile;
 45
 46	infile = fopen(input, "rb");
 47	if (!infile) {
 48		pr_debug("lzma: fopen failed on %s: '%s'\n", input, strerror(errno));
 49		return -1;
 50	}
 51
 52	ret = lzma_stream_decoder(&strm, UINT64_MAX, LZMA_CONCATENATED);
 53	if (ret != LZMA_OK) {
 54		pr_debug("lzma: lzma_stream_decoder failed %s (%d)\n", lzma_strerror(ret), ret);
 55		goto err_fclose;
 56	}
 57
 58	strm.next_in   = NULL;
 59	strm.avail_in  = 0;
 60	strm.next_out  = buf_out;
 61	strm.avail_out = sizeof(buf_out);
 62
 63	while (1) {
 64		if (strm.avail_in == 0 && !feof(infile)) {
 65			strm.next_in  = buf_in;
 66			strm.avail_in = fread(buf_in, 1, sizeof(buf_in), infile);
 67
 68			if (ferror(infile)) {
 69				pr_debug("lzma: read error: %s\n", strerror(errno));
 70				goto err_lzma_end;
 71			}
 72
 73			if (feof(infile))
 74				action = LZMA_FINISH;
 75		}
 76
 77		ret = lzma_code(&strm, action);
 78
 79		if (strm.avail_out == 0 || ret == LZMA_STREAM_END) {
 80			ssize_t write_size = sizeof(buf_out) - strm.avail_out;
 81
 82			if (writen(output_fd, buf_out, write_size) != write_size) {
 83				pr_debug("lzma: write error: %s\n", strerror(errno));
 84				goto err_lzma_end;
 85			}
 86
 87			strm.next_out  = buf_out;
 88			strm.avail_out = sizeof(buf_out);
 89		}
 90
 91		if (ret != LZMA_OK) {
 92			if (ret == LZMA_STREAM_END)
 93				break;
 94
 95			pr_debug("lzma: failed %s\n", lzma_strerror(ret));
 96			goto err_lzma_end;
 97		}
 98	}
 99
100	err = 0;
101err_lzma_end:
102	lzma_end(&strm);
103err_fclose:
104	fclose(infile);
105	return err;
106}
107
108bool lzma_is_compressed(const char *input)
109{
110	int fd = open(input, O_RDONLY);
111	const uint8_t magic[6] = { 0xFD, '7', 'z', 'X', 'Z', 0x00 };
112	char buf[6] = { 0 };
113	ssize_t rc;
114
115	if (fd < 0)
116		return -1;
117
118	rc = read(fd, buf, sizeof(buf));
119	close(fd);
120	return rc == sizeof(buf) ?
121	       memcmp(buf, magic, sizeof(buf)) == 0 : false;
122}