1 /* vi: set sw=4 ts=4: */
5 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
7 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
11 #define ZIPPED (ENABLE_FEATURE_SEAMLESS_LZMA \
12 || ENABLE_FEATURE_SEAMLESS_BZ2 \
13 || ENABLE_FEATURE_SEAMLESS_GZ \
14 /* || ENABLE_FEATURE_SEAMLESS_Z */ \
18 # include "unarchive.h"
22 /* Suppose that you are a shell. You start child processes.
23 * They work and eventually exit. You want to get user input.
24 * You read stdin. But what happens if last child switched
25 * its stdin into O_NONBLOCK mode?
27 * *** SURPRISE! It will affect the parent too! ***
28 * *** BIG SURPRISE! It stays even after child exits! ***
30 * This is a design bug in UNIX API.
31 * fcntl(0, F_SETFL, fcntl(0, F_GETFL) | O_NONBLOCK);
32 * will set nonblocking mode not only on _your_ stdin, but
33 * also on stdin of your parent, etc.
37 * fcntl(fd2, F_SETFL, fcntl(fd2, F_GETFL) | O_NONBLOCK);
38 * sets both fd1 and fd2 to O_NONBLOCK. This includes cases
39 * where duping is done implicitly by fork() etc.
42 * fcntl(fd2, F_SETFD, fcntl(fd2, F_GETFD) | O_NONBLOCK);
43 * (note SETFD, not SETFL!) but such thing doesn't exist.
45 * Alternatively, we need nonblocking_read(fd, ...) which doesn't
46 * require O_NONBLOCK dance at all. Actually, it exists:
47 * n = recv(fd, buf, len, MSG_DONTWAIT);
49 * Enables non-blocking operation; if the operation
50 * would block, EAGAIN is returned."
51 * but recv() works only for sockets!
53 * So far I don't see any good solution, I can only propose
54 * that affected readers should be careful and use this routine,
55 * which detects EAGAIN and uses poll() to wait on the fd.
56 * Thankfully, poll() doesn't care about O_NONBLOCK flag.
58 ssize_t FAST_FUNC nonblock_safe_read(int fd, void *buf, size_t count)
64 n = safe_read(fd, buf, count);
65 if (n >= 0 || errno != EAGAIN)
67 /* fd is in O_NONBLOCK mode. Wait using poll and repeat */
69 pfd[0].events = POLLIN;
70 safe_poll(pfd, 1, -1); /* note: this pulls in printf */
74 // Reads one line a-la fgets (but doesn't save terminating '\n').
75 // Reads byte-by-byte. Useful when it is important to not read ahead.
76 // Bytes are appended to pfx (which must be malloced, or NULL).
77 char* FAST_FUNC xmalloc_reads(int fd, char *buf, size_t *maxsz_p)
80 size_t sz = buf ? strlen(buf) : 0;
81 size_t maxsz = maxsz_p ? *maxsz_p : (INT_MAX - 4095);
85 if ((size_t)(p - buf) == sz) {
87 buf = xrealloc(buf, sz + 128);
91 /* nonblock_safe_read() because we are used by e.g. shells */
92 if (nonblock_safe_read(fd, p, 1) != 1) { /* EOF/error */
93 if (p == buf) { /* we read nothing */
107 return xrealloc(buf, p - buf);
110 // Read (potentially big) files in one go. File size is estimated
111 // by stat. Extra '\0' byte is appended.
112 void* FAST_FUNC xmalloc_read(int fd, size_t *maxsz_p)
115 size_t size, rd_size, total;
119 to_read = maxsz_p ? *maxsz_p : (INT_MAX - 4095); /* max to read */
121 /* Estimate file size */
122 st.st_size = 0; /* in case fstat fails, assume 0 */
124 /* /proc/N/stat files report st_size 0 */
125 /* In order to make such files readable, we add small const */
126 size = (st.st_size | 0x3ff) + 1;
133 buf = xrealloc(buf, total + size + 1);
134 rd_size = full_read(fd, buf + total, size);
135 if ((ssize_t)rd_size == (ssize_t)(-1)) { /* error */
140 if (rd_size < size) /* EOF */
142 if (to_read <= rd_size)
145 /* grow by 1/8, but in [1k..64k] bounds */
146 size = ((total / 8) | 0x3ff) + 1;
150 buf = xrealloc(buf, total + 1);
158 #ifdef USING_LSEEK_TO_GET_SIZE
159 /* Alternatively, file size can be obtained by lseek to the end.
160 * The code is slightly bigger. Retained in case fstat approach
161 * will not work for some weird cases (/proc, block devices, etc).
162 * (NB: lseek also can fail to work for some weird files) */
164 // Read (potentially big) files in one go. File size is estimated by
166 void* FAST_FUNC xmalloc_open_read_close(const char *filename, size_t *maxsz_p)
173 fd = open(filename, O_RDONLY);
177 /* /proc/N/stat files report len 0 here */
178 /* In order to make such files readable, we add small const */
179 size = 0x3ff; /* read only 1k on unseekable files */
180 len = lseek(fd, 0, SEEK_END) | 0x3ff; /* + up to 1k */
181 if (len != (off_t)-1) {
182 xlseek(fd, 0, SEEK_SET);
183 size = maxsz_p ? *maxsz_p : (INT_MAX - 4095);
188 buf = xmalloc(size + 1);
189 size = read_close(fd, buf, size);
190 if ((ssize_t)size < 0) {
194 buf = xrealloc(buf, size + 1);
203 // Read (potentially big) files in one go. File size is estimated
205 void* FAST_FUNC xmalloc_open_read_close(const char *filename, size_t *maxsz_p)
210 fd = open(filename, O_RDONLY);
214 buf = xmalloc_read(fd, maxsz_p);
219 /* Die with an error message if we can't read the entire buffer. */
220 void FAST_FUNC xread(int fd, void *buf, size_t count)
223 ssize_t size = full_read(fd, buf, count);
224 if ((size_t)size != count)
225 bb_error_msg_and_die("short read");
229 /* Die with an error message if we can't read one character. */
230 unsigned char FAST_FUNC xread_char(int fd)
237 void* FAST_FUNC xmalloc_xopen_read_close(const char *filename, size_t *maxsz_p)
239 void *buf = xmalloc_open_read_close(filename, maxsz_p);
241 bb_perror_msg_and_die("can't read '%s'", filename);
245 /* Used by e.g. rpm which gives us a fd without filename,
246 * thus we can't guess the format from filename's extension.
249 void FAST_FUNC setup_unzip_on_fd(int fd /*, int fail_if_not_detected*/)
251 const int fail_if_not_detected = 1;
259 IF_DESKTOP(long long) int FAST_FUNC (*xformer)(int src_fd, int dst_fd);
260 enum { xformer_prog = 0 };
262 enum { xformer = 0 };
263 const char *xformer_prog;
266 /* .gz and .bz2 both have 2-byte signature, and their
267 * unpack_XXX_stream wants this header skipped. */
268 xread(fd, magic.b16, sizeof(magic.b16[0]));
269 if (ENABLE_FEATURE_SEAMLESS_GZ
270 && magic.b16[0] == GZIP_MAGIC
273 xformer = unpack_gz_stream;
275 xformer_prog = "gunzip";
279 if (ENABLE_FEATURE_SEAMLESS_BZ2
280 && magic.b16[0] == BZIP2_MAGIC
283 xformer = unpack_bz2_stream;
285 xformer_prog = "bunzip2";
289 if (ENABLE_FEATURE_SEAMLESS_XZ
290 && magic.b16[0] == XZ_MAGIC1
293 xread(fd, magic.b32, sizeof(magic.b32[0]));
294 if (magic.b32[0] == XZ_MAGIC2) {
296 xformer = unpack_xz_stream;
297 /* unpack_xz_stream wants fd at position 6, no need to seek */
298 //xlseek(fd, offset, SEEK_CUR);
300 xformer_prog = "unxz";
306 /* No known magic seen */
307 if (fail_if_not_detected)
308 bb_error_msg_and_die("no gzip"
309 IF_FEATURE_SEAMLESS_BZ2("/bzip2")
310 IF_FEATURE_SEAMLESS_XZ("/xz")
312 xlseek(fd, offset, SEEK_CUR);
317 /* NOMMU version of open_transformer execs
318 * an external unzipper that wants
319 * file position at the start of the file */
320 xlseek(fd, offset, SEEK_CUR);
322 open_transformer(fd, xformer, xformer_prog);
326 int FAST_FUNC open_zipped(const char *fname)
329 return open(fname, O_RDONLY);
334 fd = open(fname, O_RDONLY);
338 sfx = strrchr(fname, '.');
341 if (ENABLE_FEATURE_SEAMLESS_LZMA && strcmp(sfx, "lzma") == 0)
342 /* .lzma has no header/signature, just trust it */
343 open_transformer(fd, unpack_lzma_stream, "unlzma");
345 if ((ENABLE_FEATURE_SEAMLESS_GZ && strcmp(sfx, "gz") == 0)
346 || (ENABLE_FEATURE_SEAMLESS_BZ2 && strcmp(sfx, "bz2") == 0)
347 || (ENABLE_FEATURE_SEAMLESS_XZ && strcmp(sfx, "xz") == 0)
349 setup_unzip_on_fd(fd /*, fail_if_not_detected: 1*/);
357 void* FAST_FUNC xmalloc_open_zipped_read_close(const char *fname, size_t *maxsz_p)
362 fd = open_zipped(fname);
366 image = xmalloc_read(fd, maxsz_p);
368 bb_perror_msg("read error from '%s'", fname);