lzma.c

  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_stream_to_file(FILE *infile, 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
 45	ret = lzma_stream_decoder(&strm, UINT64_MAX, LZMA_CONCATENATED);
 46	if (ret != LZMA_OK) {
 47		pr_debug("lzma: lzma_stream_decoder failed %s (%d)\n", lzma_strerror(ret), ret);
 48		return err;
 49	}
 50
 51	strm.next_in   = NULL;
 52	strm.avail_in  = 0;
 53	strm.next_out  = buf_out;
 54	strm.avail_out = sizeof(buf_out);
 55
 56	while (1) {
 57		if (strm.avail_in == 0 && !feof(infile)) {
 58			strm.next_in  = buf_in;
 59			strm.avail_in = fread(buf_in, 1, sizeof(buf_in), infile);
 60
 61			if (ferror(infile)) {
 62				pr_debug("lzma: read error: %s\n", strerror(errno));
 63				goto err_lzma_end;
 64			}
 65
 66			if (feof(infile))
 67				action = LZMA_FINISH;
 68		}
 69
 70		ret = lzma_code(&strm, action);
 71
 72		if (strm.avail_out == 0 || ret == LZMA_STREAM_END) {
 73			ssize_t write_size = sizeof(buf_out) - strm.avail_out;
 74
 75			if (writen(output_fd, buf_out, write_size) != write_size) {
 76				pr_debug("lzma: write error: %s\n", strerror(errno));
 77				goto err_lzma_end;
 78			}
 79
 80			strm.next_out  = buf_out;
 81			strm.avail_out = sizeof(buf_out);
 82		}
 83
 84		if (ret != LZMA_OK) {
 85			if (ret == LZMA_STREAM_END)
 86				break;
 87
 88			pr_debug("lzma: failed %s\n", lzma_strerror(ret));
 89			goto err_lzma_end;
 90		}
 91	}
 92
 93	err = 0;
 94err_lzma_end:
 95	lzma_end(&strm);
 96	return err;
 97}
 98
 99int lzma_decompress_to_file(const char *input, int output_fd)
100{
101	FILE *infile;
102	int ret;
103
104	infile = fopen(input, "rb");
105	if (!infile) {
106		pr_debug("lzma: fopen failed on %s: '%s'\n", input, strerror(errno));
107		return -1;
108	}
109
110	ret = lzma_decompress_stream_to_file(infile, output_fd);
111	fclose(infile);
112	return ret;
113}
114
115bool lzma_is_compressed(const char *input)
116{
117	int fd = open(input, O_RDONLY);
118	const uint8_t magic[6] = { 0xFD, '7', 'z', 'X', 'Z', 0x00 };
119	char buf[6] = { 0 };
120	ssize_t rc;
121
122	if (fd < 0)
123		return false;
124
125	rc = read(fd, buf, sizeof(buf));
126	close(fd);
127	return rc == sizeof(buf) ?
128	       memcmp(buf, magic, sizeof(buf)) == 0 : false;
129}