busybox/libbb/read.c

/* vi: set sw=4 ts=4: */
/*
 * Utility routines.
 *
 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

#include "libbb.h"

#define ZIPPED (ENABLE_FEATURE_SEAMLESS_LZMA \
	|| ENABLE_FEATURE_SEAMLESS_BZ2 \
	|| ENABLE_FEATURE_SEAMLESS_GZ \
	/* || ENABLE_FEATURE_SEAMLESS_Z */ \
)

#if ZIPPED
#include "unarchive.h"
#endif

ssize_t FAST_FUNC safe_read(int fd, void *buf, size_t count)
{
	ssize_t n;

	do {
		n = read(fd, buf, count);
	} while (n < 0 && errno == EINTR);

	return n;
}

/* Suppose that you are a shell. You start child processes.
 * They work and eventually exit. You want to get user input.
 * You read stdin. But what happens if last child switched
 * its stdin into O_NONBLOCK mode?
 *
 * *** SURPRISE! It will affect the parent too! ***
 * *** BIG SURPRISE! It stays even after child exits! ***
 *
 * This is a design bug in UNIX API.
 *      fcntl(0, F_SETFL, fcntl(0, F_GETFL) | O_NONBLOCK);
 * will set nonblocking mode not only on _your_ stdin, but
 * also on stdin of your parent, etc.
 *
 * In general,
 *      fd2 = dup(fd1);
 *      fcntl(fd2, F_SETFL, fcntl(fd2, F_GETFL) | O_NONBLOCK);
 * sets both fd1 and fd2 to O_NONBLOCK. This includes cases
 * where duping is done implicitly by fork() etc.
 *
 * We need
 *      fcntl(fd2, F_SETFD, fcntl(fd2, F_GETFD) | O_NONBLOCK);
 * (note SETFD, not SETFL!) but such thing doesn't exist.
 *
 * Alternatively, we need nonblocking_read(fd, ...) which doesn't
 * require O_NONBLOCK dance at all. Actually, it exists:
 *      n = recv(fd, buf, len, MSG_DONTWAIT);
 *      "MSG_DONTWAIT:
 *      Enables non-blocking operation; if the operation
 *      would block, EAGAIN is returned."
 * but recv() works only for sockets!
 *
 * So far I don't see any good solution, I can only propose
 * that affected readers should be careful and use this routine,
 * which detects EAGAIN and uses poll() to wait on the fd.
 * Thankfully, poll() doesn't care about O_NONBLOCK flag.
 */
ssize_t FAST_FUNC nonblock_safe_read(int fd, void *buf, size_t count)
{
	struct pollfd pfd[1];
	ssize_t n;

	while (1) {
		n = safe_read(fd, buf, count);
		if (n >= 0 || errno != EAGAIN)
			return n;
		/* fd is in O_NONBLOCK mode. Wait using poll and repeat */
		pfd[0].fd = fd;
		pfd[0].events = POLLIN;
		safe_poll(pfd, 1, -1);
	}
}

/*
 * Read all of the supplied buffer from a file.
 * This does multiple reads as necessary.
 * Returns the amount read, or -1 on an error.
 * A short read is returned on an end of file.
 */
ssize_t FAST_FUNC full_read(int fd, void *buf, size_t len)
{
	ssize_t cc;
	ssize_t total;

	total = 0;

	while (len) {
		cc = safe_read(fd, buf, len);

		if (cc < 0) {
			if (total) {
				/* we already have some! */
				/* user can do another read to know the error code */
				return total;
			}
			return cc; /* read() returns -1 on failure. */
		}
		if (cc == 0)
			break;
		buf = ((char *)buf) + cc;
		total += cc;
		len -= cc;
	}

	return total;
}

/* Die with an error message if we can't read the entire buffer. */
void FAST_FUNC xread(int fd, void *buf, size_t count)
{
	if (count) {
		ssize_t size = full_read(fd, buf, count);
		if ((size_t)size != count)
			bb_error_msg_and_die("short read");
	}
}

/* Die with an error message if we can't read one character. */
unsigned char FAST_FUNC xread_char(int fd)
{
	char tmp;
	xread(fd, &tmp, 1);
	return tmp;
}

// Reads one line a-la fgets (but doesn't save terminating '\n').
// Reads byte-by-byte. Useful when it is important to not read ahead.
// Bytes are appended to pfx (which must be malloced, or NULL).
char* FAST_FUNC xmalloc_reads(int fd, char *buf, size_t *maxsz_p)
{
	char *p;
	size_t sz = buf ? strlen(buf) : 0;
	size_t maxsz = maxsz_p ? *maxsz_p : (INT_MAX - 4095);

	goto jump_in;
	while (sz < maxsz) {
		if ((size_t)(p - buf) == sz) {
 jump_in:
			buf = xrealloc(buf, sz + 128);
			p = buf + sz;
			sz += 128;
		}
		/* nonblock_safe_read() because we are used by e.g. shells */
		if (nonblock_safe_read(fd, p, 1) != 1) { /* EOF/error */
			if (p == buf) { /* we read nothing */
				free(buf);
				return NULL;
			}
			break;
		}
		if (*p == '\n')
			break;
		p++;
	}
	*p = '\0';
	if (maxsz_p)
		*maxsz_p  = p - buf;
	p++;
	return xrealloc(buf, p - buf);
}

ssize_t FAST_FUNC read_close(int fd, void *buf, size_t size)
{
	/*int e;*/
	size = full_read(fd, buf, size);
	/*e = errno;*/
	close(fd);
	/*errno = e;*/
	return size;
}

ssize_t FAST_FUNC open_read_close(const char *filename, void *buf, size_t size)
{
	int fd = open(filename, O_RDONLY);
	if (fd < 0)
		return fd;
	return read_close(fd, buf, size);
}


// Read (potentially big) files in one go. File size is estimated
// by stat. Extra '\0' byte is appended.
void* FAST_FUNC xmalloc_read(int fd, size_t *maxsz_p)
{
	char *buf;
	size_t size, rd_size, total;
	size_t to_read;
	struct stat st;

	to_read = maxsz_p ? *maxsz_p : (INT_MAX - 4095); /* max to read */

	/* Estimate file size */
	st.st_size = 0; /* in case fstat fails, assume 0 */
	fstat(fd, &st);
	/* /proc/N/stat files report st_size 0 */
	/* In order to make such files readable, we add small const */
	size = (st.st_size | 0x3ff) + 1;

	total = 0;
	buf = NULL;
	while (1) {
		if (to_read < size)
			size = to_read;
		buf = xrealloc(buf, total + size + 1);
		rd_size = full_read(fd, buf + total, size);
		if ((ssize_t)rd_size == (ssize_t)(-1)) { /* error */
			free(buf);
			return NULL;
		}
		total += rd_size;
		if (rd_size < size) /* EOF */
			break;
		if (to_read <= rd_size)
			break;
		to_read -= rd_size;
		/* grow by 1/8, but in [1k..64k] bounds */
		size = ((total / 8) | 0x3ff) + 1;
		if (size > 64*1024)
			size = 64*1024;
	}
	buf = xrealloc(buf, total + 1);
	buf[total] = '\0';

	if (maxsz_p)
		*maxsz_p = total;
	return buf;
}

#ifdef USING_LSEEK_TO_GET_SIZE
/* Alternatively, file size can be obtained by lseek to the end.
 * The code is slightly bigger. Retained in case fstat approach
 * will not work for some weird cases (/proc, block devices, etc).
 * (NB: lseek also can fail to work for some weird files) */

// Read (potentially big) files in one go. File size is estimated by
// lseek to end.
void* FAST_FUNC xmalloc_open_read_close(const char *filename, size_t *maxsz_p)
{
	char *buf;
	size_t size;
	int fd;
	off_t len;

	fd = open(filename, O_RDONLY);
	if (fd < 0)
		return NULL;

	/* /proc/N/stat files report len 0 here */
	/* In order to make such files readable, we add small const */
	size = 0x3ff; /* read only 1k on unseekable files */
	len = lseek(fd, 0, SEEK_END) | 0x3ff; /* + up to 1k */
	if (len != (off_t)-1) {
		xlseek(fd, 0, SEEK_SET);
		size = maxsz_p ? *maxsz_p : (INT_MAX - 4095);
		if (len < size)
			size = len;
	}

	buf = xmalloc(size + 1);
	size = read_close(fd, buf, size);
	if ((ssize_t)size < 0) {
		free(buf);
		return NULL;
	}
	buf = xrealloc(buf, size + 1);
	buf[size] = '\0';

	if (maxsz_p)
		*maxsz_p = size;
	return buf;
}
#endif

// Read (potentially big) files in one go. File size is estimated
// by stat.
void* FAST_FUNC xmalloc_open_read_close(const char *filename, size_t *maxsz_p)
{
	char *buf;
	int fd;

	fd = open(filename, O_RDONLY);
	if (fd < 0)
		return NULL;

	buf = xmalloc_read(fd, maxsz_p);
	close(fd);
	return buf;
}

void* FAST_FUNC xmalloc_xopen_read_close(const char *filename, size_t *maxsz_p)
{
	void *buf = xmalloc_open_read_close(filename, maxsz_p);
	if (!buf)
		bb_perror_msg_and_die("can't read '%s'", filename);
	return buf;
}

int FAST_FUNC open_zipped(const char *fname)
{
#if !ZIPPED
	return open(fname, O_RDONLY);
#else
	unsigned char magic[2];
	char *sfx;
	int fd;
#if BB_MMU
	IF_DESKTOP(long long) int FAST_FUNC (*xformer)(int src_fd, int dst_fd);
	enum { xformer_prog = 0 };
#else
	enum { xformer = 0 };
	const char *xformer_prog;
#endif

	fd = open(fname, O_RDONLY);
	if (fd < 0)
		return fd;

	sfx = strrchr(fname, '.');
	if (sfx) {
		if (ENABLE_FEATURE_SEAMLESS_LZMA && strcmp(sfx, ".lzma") == 0)
			/* .lzma has no header/signature, just trust it */
			open_transformer(fd, unpack_lzma_stream, "unlzma");
		else
		if ((ENABLE_FEATURE_SEAMLESS_GZ && strcmp(sfx, ".gz") == 0)
		 || (ENABLE_FEATURE_SEAMLESS_BZ2 && strcmp(sfx, ".bz2") == 0)
		) {
			/* .gz and .bz2 both have 2-byte signature, and their
			 * unpack_XXX_stream wants this header skipped. */
			xread(fd, &magic, 2);
#if ENABLE_FEATURE_SEAMLESS_GZ
#if BB_MMU
			xformer = unpack_gz_stream;
#else
			xformer_prog = "gunzip";
#endif
#endif
			if (!ENABLE_FEATURE_SEAMLESS_GZ
			 || magic[0] != 0x1f || magic[1] != 0x8b
			) {
				if (!ENABLE_FEATURE_SEAMLESS_BZ2
				 || magic[0] != 'B' || magic[1] != 'Z'
				) {
					bb_error_msg_and_die("no gzip"
						IF_FEATURE_SEAMLESS_BZ2("/bzip2")
						" magic");
				}
#if BB_MMU
				xformer = unpack_bz2_stream;
#else
				xformer_prog = "bunzip2";
#endif
			} else {
#if !BB_MMU
				/* NOMMU version of open_transformer execs
				 * an external unzipper that wants
				 * file position at the start of the file */
				xlseek(fd, 0, SEEK_SET);
#endif
			}
			open_transformer(fd, xformer, xformer_prog);
		}
	}

	return fd;
#endif
}

void* FAST_FUNC xmalloc_open_zipped_read_close(const char *fname, size_t *maxsz_p)
{
	int fd;
	char *image;

	fd = open_zipped(fname);
	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;
}
1	niro	532	/* vi: set sw=4 ts=4: */
2			/*
3			* Utility routines.
4			*
5			* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
6			*
7			* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
8			*/
9
10			#include "libbb.h"
11
12	niro	816	#define ZIPPED (ENABLE_FEATURE_SEAMLESS_LZMA \
13			\|\| ENABLE_FEATURE_SEAMLESS_BZ2 \
14			\|\| ENABLE_FEATURE_SEAMLESS_GZ \
15			/* \|\| ENABLE_FEATURE_SEAMLESS_Z */ \
16			)
17
18			#if ZIPPED
19			#include "unarchive.h"
20			#endif
21
22			ssize_t FAST_FUNC safe_read(int fd, void *buf, size_t count)
23	niro	532	{
24			ssize_t n;
25
26			do {
27			n = read(fd, buf, count);
28			} while (n < 0 && errno == EINTR);
29
30			return n;
31			}
32
33	niro	816	/* Suppose that you are a shell. You start child processes.
34			* They work and eventually exit. You want to get user input.
35			* You read stdin. But what happens if last child switched
36			* its stdin into O_NONBLOCK mode?
37			*
38			* * SURPRISE! It will affect the parent too! *
39			* * BIG SURPRISE! It stays even after child exits! *
40			*
41			* This is a design bug in UNIX API.
42	niro	984	* fcntl(0, F_SETFL, fcntl(0, F_GETFL) \| O_NONBLOCK);
43	niro	816	* will set nonblocking mode not only on _your_ stdin, but
44			* also on stdin of your parent, etc.
45			*
46			* In general,
47			* fd2 = dup(fd1);
48	niro	984	* fcntl(fd2, F_SETFL, fcntl(fd2, F_GETFL) \| O_NONBLOCK);
49	niro	816	* sets both fd1 and fd2 to O_NONBLOCK. This includes cases
50			* where duping is done implicitly by fork() etc.
51			*
52			* We need
53	niro	984	* fcntl(fd2, F_SETFD, fcntl(fd2, F_GETFD) \| O_NONBLOCK);
54	niro	816	* (note SETFD, not SETFL!) but such thing doesn't exist.
55			*
56			* Alternatively, we need nonblocking_read(fd, ...) which doesn't
57			* require O_NONBLOCK dance at all. Actually, it exists:
58			* n = recv(fd, buf, len, MSG_DONTWAIT);
59			* "MSG_DONTWAIT:
60			* Enables non-blocking operation; if the operation
61			* would block, EAGAIN is returned."
62			* but recv() works only for sockets!
63			*
64			* So far I don't see any good solution, I can only propose
65			* that affected readers should be careful and use this routine,
66			* which detects EAGAIN and uses poll() to wait on the fd.
67			* Thankfully, poll() doesn't care about O_NONBLOCK flag.
68			*/
69			ssize_t FAST_FUNC nonblock_safe_read(int fd, void *buf, size_t count)
70			{
71			struct pollfd pfd[1];
72			ssize_t n;
73
74			while (1) {
75			n = safe_read(fd, buf, count);
76			if (n >= 0 \|\| errno != EAGAIN)
77			return n;
78			/* fd is in O_NONBLOCK mode. Wait using poll and repeat */
79			pfd[0].fd = fd;
80			pfd[0].events = POLLIN;
81			safe_poll(pfd, 1, -1);
82			}
83			}
84
85	niro	532	/*
86			* Read all of the supplied buffer from a file.
87			* This does multiple reads as necessary.
88			* Returns the amount read, or -1 on an error.
89			* A short read is returned on an end of file.
90			*/
91	niro	816	ssize_t FAST_FUNC full_read(int fd, void *buf, size_t len)
92	niro	532	{
93			ssize_t cc;
94			ssize_t total;
95
96			total = 0;
97
98			while (len) {
99			cc = safe_read(fd, buf, len);
100
101	niro	816	if (cc < 0) {
102			if (total) {
103			/* we already have some! */
104			/* user can do another read to know the error code */
105			return total;
106			}
107			return cc; /* read() returns -1 on failure. */
108			}
109	niro	532	if (cc == 0)
110			break;
111			buf = ((char *)buf) + cc;
112			total += cc;
113			len -= cc;
114			}
115
116			return total;
117			}
118
119	niro	816	/* Die with an error message if we can't read the entire buffer. */
120			void FAST_FUNC xread(int fd, void *buf, size_t count)
121	niro	532	{
122			if (count) {
123			ssize_t size = full_read(fd, buf, count);
124	niro	816	if ((size_t)size != count)
125	niro	532	bb_error_msg_and_die("short read");
126			}
127			}
128
129	niro	816	/* Die with an error message if we can't read one character. */
130			unsigned char FAST_FUNC xread_char(int fd)
131	niro	532	{
132			char tmp;
133			xread(fd, &tmp, 1);
134			return tmp;
135			}
136
137	niro	816	// Reads one line a-la fgets (but doesn't save terminating '\n').
138			// Reads byte-by-byte. Useful when it is important to not read ahead.
139			// Bytes are appended to pfx (which must be malloced, or NULL).
140			char* FAST_FUNC xmalloc_reads(int fd, char buf, size_t maxsz_p)
141	niro	532	{
142			char *p;
143	niro	816	size_t sz = buf ? strlen(buf) : 0;
144	niro	984	size_t maxsz = maxsz_p ? *maxsz_p : (INT_MAX - 4095);
145	niro	532
146	niro	816	goto jump_in;
147			while (sz < maxsz) {
148			if ((size_t)(p - buf) == sz) {
149			jump_in:
150			buf = xrealloc(buf, sz + 128);
151			p = buf + sz;
152			sz += 128;
153			}
154			/* nonblock_safe_read() because we are used by e.g. shells */
155			if (nonblock_safe_read(fd, p, 1) != 1) { /* EOF/error */
156			if (p == buf) { /* we read nothing */
157			free(buf);
158			return NULL;
159			}
160			break;
161			}
162			if (*p == '\n')
163			break;
164			p++;
165	niro	532	}
166	niro	816	*p = '\0';
167			if (maxsz_p)
168			*maxsz_p = p - buf;
169			p++;
170			return xrealloc(buf, p - buf);
171	niro	532	}
172
173	niro	816	ssize_t FAST_FUNC read_close(int fd, void *buf, size_t size)
174	niro	532	{
175	niro	816	/int e;/
176	niro	532	size = full_read(fd, buf, size);
177	niro	816	/e = errno;/
178	niro	532	close(fd);
179	niro	816	/errno = e;/
180	niro	532	return size;
181			}
182
183	niro	816	ssize_t FAST_FUNC open_read_close(const char filename, void buf, size_t size)
184	niro	532	{
185			int fd = open(filename, O_RDONLY);
186			if (fd < 0)
187			return fd;
188			return read_close(fd, buf, size);
189			}
190
191	niro	816
192			// Read (potentially big) files in one go. File size is estimated
193			// by stat. Extra '\0' byte is appended.
194			void* FAST_FUNC xmalloc_read(int fd, size_t *maxsz_p)
195	niro	532	{
196			char *buf;
197	niro	816	size_t size, rd_size, total;
198			size_t to_read;
199			struct stat st;
200
201	niro	984	to_read = maxsz_p ? maxsz_p : (INT_MAX - 4095); / max to read */
202	niro	816
203			/* Estimate file size */
204			st.st_size = 0; /* in case fstat fails, assume 0 */
205			fstat(fd, &st);
206			/* /proc/N/stat files report st_size 0 */
207			/* In order to make such files readable, we add small const */
208			size = (st.st_size \| 0x3ff) + 1;
209
210			total = 0;
211			buf = NULL;
212			while (1) {
213			if (to_read < size)
214			size = to_read;
215			buf = xrealloc(buf, total + size + 1);
216			rd_size = full_read(fd, buf + total, size);
217			if ((ssize_t)rd_size == (ssize_t)(-1)) { /* error */
218			free(buf);
219			return NULL;
220			}
221			total += rd_size;
222			if (rd_size < size) /* EOF */
223			break;
224			if (to_read <= rd_size)
225			break;
226			to_read -= rd_size;
227			/* grow by 1/8, but in [1k..64k] bounds */
228			size = ((total / 8) \| 0x3ff) + 1;
229			if (size > 64*1024)
230			size = 64*1024;
231			}
232	niro	984	buf = xrealloc(buf, total + 1);
233	niro	816	buf[total] = '\0';
234
235			if (maxsz_p)
236			*maxsz_p = total;
237			return buf;
238			}
239
240			#ifdef USING_LSEEK_TO_GET_SIZE
241			/* Alternatively, file size can be obtained by lseek to the end.
242			* The code is slightly bigger. Retained in case fstat approach
243			* will not work for some weird cases (/proc, block devices, etc).
244			* (NB: lseek also can fail to work for some weird files) */
245
246			// Read (potentially big) files in one go. File size is estimated by
247			// lseek to end.
248			void* FAST_FUNC xmalloc_open_read_close(const char filename, size_t maxsz_p)
249			{
250			char *buf;
251			size_t size;
252			int fd;
253			off_t len;
254
255			fd = open(filename, O_RDONLY);
256			if (fd < 0)
257			return NULL;
258
259	niro	532	/* /proc/N/stat files report len 0 here */
260			/* In order to make such files readable, we add small const */
261	niro	816	size = 0x3ff; /* read only 1k on unseekable files */
262			len = lseek(fd, 0, SEEK_END) \| 0x3ff; /* + up to 1k */
263			if (len != (off_t)-1) {
264			xlseek(fd, 0, SEEK_SET);
265	niro	984	size = maxsz_p ? *maxsz_p : (INT_MAX - 4095);
266	niro	816	if (len < size)
267			size = len;
268			}
269	niro	532
270			buf = xmalloc(size + 1);
271			size = read_close(fd, buf, size);
272	niro	816	if ((ssize_t)size < 0) {
273			free(buf);
274			return NULL;
275			}
276	niro	984	buf = xrealloc(buf, size + 1);
277	niro	532	buf[size] = '\0';
278	niro	816
279			if (maxsz_p)
280			*maxsz_p = size;
281	niro	532	return buf;
282			}
283	niro	816	#endif
284
285			// Read (potentially big) files in one go. File size is estimated
286			// by stat.
287			void* FAST_FUNC xmalloc_open_read_close(const char filename, size_t maxsz_p)
288			{
289			char *buf;
290			int fd;
291
292			fd = open(filename, O_RDONLY);
293			if (fd < 0)
294			return NULL;
295
296			buf = xmalloc_read(fd, maxsz_p);
297			close(fd);
298			return buf;
299			}
300
301			void* FAST_FUNC xmalloc_xopen_read_close(const char filename, size_t maxsz_p)
302			{
303			void *buf = xmalloc_open_read_close(filename, maxsz_p);
304			if (!buf)
305			bb_perror_msg_and_die("can't read '%s'", filename);
306			return buf;
307			}
308
309			int FAST_FUNC open_zipped(const char *fname)
310			{
311			#if !ZIPPED
312			return open(fname, O_RDONLY);
313			#else
314			unsigned char magic[2];
315			char *sfx;
316			int fd;
317			#if BB_MMU
318	niro	984	IF_DESKTOP(long long) int FAST_FUNC (*xformer)(int src_fd, int dst_fd);
319	niro	816	enum { xformer_prog = 0 };
320			#else
321			enum { xformer = 0 };
322			const char *xformer_prog;
323			#endif
324
325			fd = open(fname, O_RDONLY);
326			if (fd < 0)
327			return fd;
328
329			sfx = strrchr(fname, '.');
330			if (sfx) {
331			if (ENABLE_FEATURE_SEAMLESS_LZMA && strcmp(sfx, ".lzma") == 0)
332			/* .lzma has no header/signature, just trust it */
333			open_transformer(fd, unpack_lzma_stream, "unlzma");
334			else
335			if ((ENABLE_FEATURE_SEAMLESS_GZ && strcmp(sfx, ".gz") == 0)
336			\|\| (ENABLE_FEATURE_SEAMLESS_BZ2 && strcmp(sfx, ".bz2") == 0)
337			) {
338			/* .gz and .bz2 both have 2-byte signature, and their
339	niro	984	* unpack_XXX_stream wants this header skipped. */
340	niro	816	xread(fd, &magic, 2);
341			#if ENABLE_FEATURE_SEAMLESS_GZ
342			#if BB_MMU
343			xformer = unpack_gz_stream;
344			#else
345			xformer_prog = "gunzip";
346			#endif
347			#endif
348			if (!ENABLE_FEATURE_SEAMLESS_GZ
349			\|\| magic[0] != 0x1f \|\| magic[1] != 0x8b
350			) {
351			if (!ENABLE_FEATURE_SEAMLESS_BZ2
352			\|\| magic[0] != 'B' \|\| magic[1] != 'Z'
353			) {
354			bb_error_msg_and_die("no gzip"
355	niro	984	IF_FEATURE_SEAMLESS_BZ2("/bzip2")
356	niro	816	" magic");
357			}
358			#if BB_MMU
359			xformer = unpack_bz2_stream;
360			#else
361			xformer_prog = "bunzip2";
362			#endif
363			} else {
364			#if !BB_MMU
365			/* NOMMU version of open_transformer execs
366			* an external unzipper that wants
367			* file position at the start of the file */
368			xlseek(fd, 0, SEEK_SET);
369			#endif
370			}
371			open_transformer(fd, xformer, xformer_prog);
372			}
373			}
374
375			return fd;
376			#endif
377			}
378
379			void* FAST_FUNC xmalloc_open_zipped_read_close(const char fname, size_t maxsz_p)
380			{
381			int fd;
382			char *image;
383
384			fd = open_zipped(fname);
385			if (fd < 0)
386			return NULL;
387
388			image = xmalloc_read(fd, maxsz_p);
389			if (!image)
390			bb_perror_msg("read error from '%s'", fname);
391			close(fd);
392
393			return image;
394			}