busybox/archival/libarchive/open_transformer.c
Denys Vlasenko eda83c9e69 comment fix
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2019-05-26 13:46:49 +02:00

387 lines
9.5 KiB
C

/* vi: set sw=4 ts=4: */
/*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
#include "libbb.h"
#include "bb_archive.h"
void FAST_FUNC init_transformer_state(transformer_state_t *xstate)
{
memset(xstate, 0, sizeof(*xstate));
}
int FAST_FUNC check_signature16(transformer_state_t *xstate, unsigned magic16)
{
if (!xstate->signature_skipped) {
uint16_t magic2;
if (full_read(xstate->src_fd, &magic2, 2) != 2 || magic2 != magic16) {
bb_error_msg("invalid magic");
return -1;
}
xstate->signature_skipped = 2;
}
return 0;
}
ssize_t FAST_FUNC transformer_write(transformer_state_t *xstate, const void *buf, size_t bufsize)
{
ssize_t nwrote;
if (xstate->mem_output_size_max != 0) {
size_t pos = xstate->mem_output_size;
size_t size;
size = (xstate->mem_output_size += bufsize);
if (size > xstate->mem_output_size_max) {
free(xstate->mem_output_buf);
xstate->mem_output_buf = NULL;
bb_perror_msg("buffer %u too small", (unsigned)xstate->mem_output_size_max);
nwrote = -1;
goto ret;
}
xstate->mem_output_buf = xrealloc(xstate->mem_output_buf, size + 1);
memcpy(xstate->mem_output_buf + pos, buf, bufsize);
xstate->mem_output_buf[size] = '\0';
nwrote = bufsize;
} else {
nwrote = full_write(xstate->dst_fd, buf, bufsize);
if (nwrote != (ssize_t)bufsize) {
bb_perror_msg("write");
nwrote = -1;
goto ret;
}
}
ret:
return nwrote;
}
ssize_t FAST_FUNC xtransformer_write(transformer_state_t *xstate, const void *buf, size_t bufsize)
{
ssize_t nwrote = transformer_write(xstate, buf, bufsize);
if (nwrote != (ssize_t)bufsize) {
xfunc_die();
}
return nwrote;
}
void check_errors_in_children(int signo)
{
int status;
if (!signo) {
/* block waiting for any child */
if (wait(&status) < 0)
//FIXME: check EINTR?
return; /* probably there are no children */
goto check_status;
}
/* Wait for any child without blocking */
for (;;) {
if (wait_any_nohang(&status) < 0)
//FIXME: check EINTR?
/* wait failed?! I'm confused... */
return;
check_status:
/*if (WIFEXITED(status) && WEXITSTATUS(status) == 0)*/
/* On Linux, the above can be checked simply as: */
if (status == 0)
/* this child exited with 0 */
continue;
/* Cannot happen:
if (!WIFSIGNALED(status) && !WIFEXITED(status)) ???;
*/
bb_got_signal = 1;
}
}
/* transformer(), more than meets the eye */
#if BB_MMU
void FAST_FUNC fork_transformer(int fd,
int signature_skipped,
IF_DESKTOP(long long) int FAST_FUNC (*transformer)(transformer_state_t *xstate)
)
#else
void FAST_FUNC fork_transformer(int fd, const char *transform_prog)
#endif
{
struct fd_pair fd_pipe;
int pid;
xpiped_pair(fd_pipe);
pid = BB_MMU ? xfork() : xvfork();
if (pid == 0) {
/* Child */
close(fd_pipe.rd); /* we don't want to read from the parent */
// FIXME: error check?
#if BB_MMU
{
IF_DESKTOP(long long) int r;
transformer_state_t xstate;
init_transformer_state(&xstate);
xstate.signature_skipped = signature_skipped;
xstate.src_fd = fd;
xstate.dst_fd = fd_pipe.wr;
r = transformer(&xstate);
if (ENABLE_FEATURE_CLEAN_UP) {
close(fd_pipe.wr); /* send EOF */
close(fd);
}
/* must be _exit! bug was actually seen here */
_exit(/*error if:*/ r < 0);
}
#else
{
char *argv[4];
xmove_fd(fd, 0);
xmove_fd(fd_pipe.wr, 1);
argv[0] = (char*)transform_prog;
argv[1] = (char*)"-cf";
argv[2] = (char*)"-";
argv[3] = NULL;
BB_EXECVP(transform_prog, argv);
bb_perror_msg_and_die("can't execute '%s'", transform_prog);
}
#endif
/* notreached */
}
/* parent process */
close(fd_pipe.wr); /* don't want to write to the child */
xmove_fd(fd_pipe.rd, fd);
}
#if SEAMLESS_COMPRESSION
/* Used by e.g. rpm which gives us a fd without filename,
* thus we can't guess the format from filename's extension.
*/
static transformer_state_t *setup_transformer_on_fd(int fd, int fail_if_not_compressed)
{
transformer_state_t *xstate;
xstate = xzalloc(sizeof(*xstate));
xstate->src_fd = fd;
/* .gz and .bz2 both have 2-byte signature, and their
* unpack_XXX_stream wants this header skipped. */
xstate->signature_skipped = 2;
xread(fd, xstate->magic.b16, 2);
if (ENABLE_FEATURE_SEAMLESS_GZ
&& xstate->magic.b16[0] == GZIP_MAGIC
) {
xstate->xformer = unpack_gz_stream;
USE_FOR_NOMMU(xstate->xformer_prog = "gunzip";)
goto found_magic;
}
if (ENABLE_FEATURE_SEAMLESS_Z
&& xstate->magic.b16[0] == COMPRESS_MAGIC
) {
xstate->xformer = unpack_Z_stream;
USE_FOR_NOMMU(xstate->xformer_prog = "uncompress";)
goto found_magic;
}
if (ENABLE_FEATURE_SEAMLESS_BZ2
&& xstate->magic.b16[0] == BZIP2_MAGIC
) {
xstate->xformer = unpack_bz2_stream;
USE_FOR_NOMMU(xstate->xformer_prog = "bunzip2";)
goto found_magic;
}
if (ENABLE_FEATURE_SEAMLESS_XZ
&& xstate->magic.b16[0] == XZ_MAGIC1
) {
uint32_t v32;
xstate->signature_skipped = 6;
xread(fd, &xstate->magic.b16[1], 4);
move_from_unaligned32(v32, &xstate->magic.b16[1]);
if (v32 == XZ_MAGIC2) {
xstate->xformer = unpack_xz_stream;
USE_FOR_NOMMU(xstate->xformer_prog = "unxz";)
goto found_magic;
}
}
/* No known magic seen */
if (fail_if_not_compressed)
bb_error_msg_and_die("no gzip"
IF_FEATURE_SEAMLESS_BZ2("/bzip2")
IF_FEATURE_SEAMLESS_XZ("/xz")
" magic");
/* Some callers expect this function to "consume" fd
* even if data is not compressed. In this case,
* we return a state with trivial transformer.
*/
// USE_FOR_MMU(xstate->xformer = copy_stream;)
// USE_FOR_NOMMU(xstate->xformer_prog = "cat";)
found_magic:
return xstate;
}
static void fork_transformer_and_free(transformer_state_t *xstate)
{
# if BB_MMU
fork_transformer_with_no_sig(xstate->src_fd, xstate->xformer);
# else
/* NOMMU version of fork_transformer execs
* an external unzipper that wants
* file position at the start of the file.
*/
xlseek(xstate->src_fd, - xstate->signature_skipped, SEEK_CUR);
xstate->signature_skipped = 0;
fork_transformer_with_sig(xstate->src_fd, xstate->xformer, xstate->xformer_prog);
# endif
free(xstate);
}
/* Used by e.g. rpm which gives us a fd without filename,
* thus we can't guess the format from filename's extension.
*/
int FAST_FUNC setup_unzip_on_fd(int fd, int fail_if_not_compressed)
{
transformer_state_t *xstate = setup_transformer_on_fd(fd, fail_if_not_compressed);
if (!xstate->xformer) {
free(xstate);
return 1;
}
fork_transformer_and_free(xstate);
return 0;
}
#if ENABLE_FEATURE_SEAMLESS_LZMA
/* ...and custom version for LZMA */
void FAST_FUNC setup_lzma_on_fd(int fd)
{
transformer_state_t *xstate = xzalloc(sizeof(*xstate));
xstate->src_fd = fd;
xstate->xformer = unpack_lzma_stream;
USE_FOR_NOMMU(xstate->xformer_prog = "unlzma";)
fork_transformer_and_free(xstate);
}
#endif
static transformer_state_t *open_transformer(const char *fname, int fail_if_not_compressed)
{
transformer_state_t *xstate;
int fd;
fd = open(fname, O_RDONLY);
if (fd < 0)
return NULL;
if (ENABLE_FEATURE_SEAMLESS_LZMA) {
/* .lzma has no header/signature, can only detect it by extension */
if (is_suffixed_with(fname, ".lzma")) {
xstate = xzalloc(sizeof(*xstate));
xstate->src_fd = fd;
xstate->xformer = unpack_lzma_stream;
USE_FOR_NOMMU(xstate->xformer_prog = "unlzma";)
return xstate;
}
}
xstate = setup_transformer_on_fd(fd, fail_if_not_compressed);
return xstate;
}
int FAST_FUNC open_zipped(const char *fname, int fail_if_not_compressed)
{
int fd;
transformer_state_t *xstate;
xstate = open_transformer(fname, fail_if_not_compressed);
if (!xstate)
return -1;
fd = xstate->src_fd;
# if BB_MMU
if (xstate->xformer) {
fork_transformer_with_no_sig(fd, xstate->xformer);
} else {
/* the file is not compressed */
xlseek(fd, - xstate->signature_skipped, SEEK_CUR);
xstate->signature_skipped = 0;
}
# else
/* NOMMU can't avoid the seek :( */
xlseek(fd, - xstate->signature_skipped, SEEK_CUR);
xstate->signature_skipped = 0;
if (xstate->xformer) {
fork_transformer_with_sig(fd, xstate->xformer, xstate->xformer_prog);
} /* else: the file is not compressed */
# endif
free(xstate);
return fd;
}
void* FAST_FUNC xmalloc_open_zipped_read_close(const char *fname, size_t *maxsz_p)
{
# if 1
transformer_state_t *xstate;
char *image;
xstate = open_transformer(fname, /*fail_if_not_compressed:*/ 0);
if (!xstate) /* file open error */
return NULL;
image = NULL;
if (xstate->xformer) {
/* In-memory decompression */
xstate->mem_output_size_max = maxsz_p ? *maxsz_p : (size_t)(INT_MAX - 4095);
xstate->xformer(xstate);
if (xstate->mem_output_buf) {
image = xstate->mem_output_buf;
if (maxsz_p)
*maxsz_p = xstate->mem_output_size;
}
} else {
/* File is not compressed.
* We already read first few bytes, account for that.
* Example where it happens:
* "modinfo MODULE.ko" (not compressed)
* open("MODULE.ko", O_RDONLY|O_LARGEFILE) = 4
* read(4, "\177E", 2) = 2
* fstat64(4, ...)
* mmap(...)
* read(4, "LF\2\1\1\0\0\0\0"...
* ...and we avoided seeking on the fd! :)
*/
image = xmalloc_read_with_initial_buf(
xstate->src_fd,
maxsz_p,
xmemdup(&xstate->magic, xstate->signature_skipped),
xstate->signature_skipped
);
xstate->signature_skipped = 0;
}
if (!image)
bb_perror_msg("read error from '%s'", fname);
close(xstate->src_fd);
free(xstate);
return image;
# else
/* This version forks a subprocess - much more expensive */
int fd;
char *image;
fd = open_zipped(fname, /*fail_if_not_compressed:*/ 0);
if (fd < 0)
return NULL;
image = xmalloc_read(fd, maxsz_p);
if (!image)
bb_perror_msg("read error from '%s'", fname);
close(fd);
return image;
# endif
}
#endif /* SEAMLESS_COMPRESSION */