journal/compress: add stream compression/decompression functions

This commit is contained in:
Zbigniew Jędrzejewski-Szmek
2014-06-26 01:41:04 -04:00
parent 76cc0bf682
commit 355b59e252
4 changed files with 210 additions and 6 deletions
+151 -3
View File
@@ -22,10 +22,12 @@
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <lzma.h>
#include "macro.h"
#include "compress.h"
#include "macro.h"
#include "util.h"
bool compress_blob(const void *src, uint64_t src_size, void *dst, uint64_t *dst_size) {
lzma_ret ret;
@@ -40,12 +42,12 @@ bool compress_blob(const void *src, uint64_t src_size, void *dst, uint64_t *dst_
* compressed result is longer than the original */
ret = lzma_easy_buffer_encode(LZMA_PRESET_DEFAULT, LZMA_CHECK_NONE, NULL,
src, src_size, dst, &out_pos, *dst_size);
src, src_size, dst, &out_pos, src_size);
if (ret != LZMA_OK)
return false;
/* Is it actually shorter? */
if (out_pos == *dst_size)
if (out_pos == src_size)
return false;
*dst_size = out_pos;
@@ -200,3 +202,149 @@ fail:
return b;
}
int compress_stream(int fdf, int fdt, off_t max_bytes) {
_cleanup_(lzma_end) lzma_stream s = LZMA_STREAM_INIT;
lzma_ret ret;
uint8_t buf[BUFSIZ], out[BUFSIZ];
lzma_action action = LZMA_RUN;
assert(fdf >= 0);
assert(fdt >= 0);
ret = lzma_easy_encoder(&s, LZMA_PRESET_DEFAULT, LZMA_CHECK_CRC64);
if (ret != LZMA_OK) {
log_error("Failed to initialize XZ encoder: code %d", ret);
return -EINVAL;
}
for (;;) {
if (s.avail_in == 0 && action == LZMA_RUN) {
size_t m = sizeof(buf);
ssize_t n;
if (max_bytes != -1 && m > (size_t) max_bytes)
m = max_bytes;
n = read(fdf, buf, m);
if (n < 0)
return -errno;
if (n == 0)
action = LZMA_FINISH;
else {
s.next_in = buf;
s.avail_in = n;
if (max_bytes != -1) {
assert(max_bytes >= n);
max_bytes -= n;
}
}
}
if (s.avail_out == 0) {
s.next_out = out;
s.avail_out = sizeof(out);
}
ret = lzma_code(&s, action);
if (ret != LZMA_OK && ret != LZMA_STREAM_END) {
log_error("Compression failed: code %d", ret);
return -EBADMSG;
}
if (s.avail_out == 0 || ret == LZMA_STREAM_END) {
ssize_t n, k;
n = sizeof(out) - s.avail_out;
errno = 0;
k = loop_write(fdt, out, n, false);
if (k < 0)
return k;
if (k != n)
return errno ? -errno : -EIO;
if (ret == LZMA_STREAM_END) {
log_debug("Compression finished (%zu -> %zu bytes, %.1f%%)",
s.total_in, s.total_out,
(double) s.total_out / s.total_in * 100);
return 0;
}
}
}
}
int decompress_stream(int fdf, int fdt, off_t max_bytes) {
_cleanup_(lzma_end) lzma_stream s = LZMA_STREAM_INIT;
lzma_ret ret;
uint8_t buf[BUFSIZ], out[BUFSIZ];
lzma_action action = LZMA_RUN;
assert(fdf >= 0);
assert(fdt >= 0);
ret = lzma_stream_decoder(&s, UINT64_MAX, 0);
if (ret != LZMA_OK) {
log_error("Failed to initialize XZ decoder: code %d", ret);
return -EINVAL;
}
for (;;) {
if (s.avail_in == 0 && action == LZMA_RUN) {
ssize_t n;
n = read(fdf, buf, sizeof(buf));
if (n < 0)
return -errno;
if (n == 0)
action = LZMA_FINISH;
else {
s.next_in = buf;
s.avail_in = n;
}
}
if (s.avail_out == 0) {
s.next_out = out;
s.avail_out = sizeof(out);
}
ret = lzma_code(&s, action);
if (ret != LZMA_OK && ret != LZMA_STREAM_END) {
log_error("Decompression failed: code %d", ret);
return -EBADMSG;
}
if (s.avail_out == 0 || ret == LZMA_STREAM_END) {
ssize_t n, k;
n = sizeof(out) - s.avail_out;
if (max_bytes != -1) {
if (max_bytes < n)
return -E2BIG;
max_bytes -= n;
}
errno = 0;
k = loop_write(fdt, out, n, false);
if (k < 0)
return k;
if (k != n)
return errno ? -errno : -EIO;
if (ret == LZMA_STREAM_END) {
log_debug("Decompression finished (%zu -> %zu bytes, %.1f%%)",
s.total_in, s.total_out,
(double) s.total_out / s.total_in * 100);
return 0;
}
}
}
}
+4
View File
@@ -23,6 +23,7 @@
#include <inttypes.h>
#include <stdbool.h>
#include <unistd.h>
bool compress_blob(const void *src, uint64_t src_size, void *dst, uint64_t *dst_size);
@@ -33,3 +34,6 @@ bool uncompress_startswith(const void *src, uint64_t src_size,
void **buffer, uint64_t *buffer_size,
const void *prefix, uint64_t prefix_len,
uint8_t extra);
int compress_stream(int fdf, int fdt, off_t max_size);
int decompress_stream(int fdf, int fdt, off_t max_size);
+54
View File
@@ -68,9 +68,63 @@ static void test_uncompress_startswith(void) {
"barbarbar", 9, ' '));
}
static void test_compress_stream(const char *srcfile) {
_cleanup_close_ int src = -1, dst = -1, dst2 = -1;
char pattern[] = "/tmp/systemd-test.xz.XXXXXX",
pattern2[] = "/tmp/systemd-test.xz.XXXXXX";
int r;
_cleanup_free_ char *cmd, *cmd2;
struct stat st = {};
log_debug("/* create source from %s */", srcfile);
assert_se((src = open(srcfile, O_RDONLY|O_CLOEXEC)) >= 0);
log_debug("/* test compression */");
assert_se((dst = mkostemp_safe(pattern, O_RDWR|O_CLOEXEC)) >= 0);
r = compress_stream(src, dst, -1);
assert(r == 0);
assert_se(asprintf(&cmd, "xzcat %s | diff %s -", pattern, srcfile) > 0);
assert_se(system(cmd) == 0);
log_debug("/* test decompression */");
assert_se((dst2 = mkostemp_safe(pattern2, O_RDWR|O_CLOEXEC)) >= 0);
assert_se(stat(srcfile, &st) == 0);
assert_se(lseek(dst, 0, SEEK_SET) == 0);
r = decompress_stream(dst, dst2, st.st_size);
assert(r == 0);
assert_se(asprintf(&cmd2, "diff %s %s", srcfile, pattern2) > 0);
assert_se(system(cmd2) == 0);
log_debug("/* test faulty decompression */");
assert_se(lseek(dst, 1, SEEK_SET) == 1);
r = decompress_stream(dst, dst2, st.st_size);
assert(r == -EBADMSG);
assert_se(lseek(dst, 0, SEEK_SET) == 0);
assert_se(lseek(dst2, 0, SEEK_SET) == 0);
r = decompress_stream(dst, dst2, st.st_size - 1);
assert(r == -E2BIG);
assert_se(unlink(pattern) == 0);
assert_se(unlink(pattern2) == 0);
}
int main(int argc, char *argv[]) {
log_set_max_level(LOG_DEBUG);
test_compress_uncompress();
test_uncompress_startswith();
test_compress_stream(argv[0]);
return 0;
}
+1 -3
View File
@@ -29,9 +29,7 @@ int copy_bytes(int fdf, int fdt, off_t max_bytes) {
for (;;) {
char buf[PIPE_BUF];
ssize_t n, k;
size_t m;
m = sizeof(buf);
size_t m = sizeof(buf);
if (max_bytes != (off_t) -1) {