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-rw-r--r--libbb/read.c365
1 files changed, 0 insertions, 365 deletions
diff --git a/libbb/read.c b/libbb/read.c
index b1eb3f24b..1ed7c5f92 100644
--- a/libbb/read.c
+++ b/libbb/read.c
@@ -8,16 +8,6 @@
8 */ 8 */
9#include "libbb.h" 9#include "libbb.h"
10 10
11#define ZIPPED (ENABLE_FEATURE_SEAMLESS_LZMA \
12 || ENABLE_FEATURE_SEAMLESS_BZ2 \
13 || ENABLE_FEATURE_SEAMLESS_GZ \
14 /* || ENABLE_FEATURE_SEAMLESS_Z */ \
15)
16
17#if ZIPPED
18# include "unarchive.h"
19#endif
20
21ssize_t FAST_FUNC safe_read(int fd, void *buf, size_t count) 11ssize_t FAST_FUNC safe_read(int fd, void *buf, size_t count)
22{ 12{
23 ssize_t n; 13 ssize_t n;
@@ -29,58 +19,6 @@ ssize_t FAST_FUNC safe_read(int fd, void *buf, size_t count)
29 return n; 19 return n;
30} 20}
31 21
32/* Suppose that you are a shell. You start child processes.
33 * They work and eventually exit. You want to get user input.
34 * You read stdin. But what happens if last child switched
35 * its stdin into O_NONBLOCK mode?
36 *
37 * *** SURPRISE! It will affect the parent too! ***
38 * *** BIG SURPRISE! It stays even after child exits! ***
39 *
40 * This is a design bug in UNIX API.
41 * fcntl(0, F_SETFL, fcntl(0, F_GETFL) | O_NONBLOCK);
42 * will set nonblocking mode not only on _your_ stdin, but
43 * also on stdin of your parent, etc.
44 *
45 * In general,
46 * fd2 = dup(fd1);
47 * fcntl(fd2, F_SETFL, fcntl(fd2, F_GETFL) | O_NONBLOCK);
48 * sets both fd1 and fd2 to O_NONBLOCK. This includes cases
49 * where duping is done implicitly by fork() etc.
50 *
51 * We need
52 * fcntl(fd2, F_SETFD, fcntl(fd2, F_GETFD) | O_NONBLOCK);
53 * (note SETFD, not SETFL!) but such thing doesn't exist.
54 *
55 * Alternatively, we need nonblocking_read(fd, ...) which doesn't
56 * require O_NONBLOCK dance at all. Actually, it exists:
57 * n = recv(fd, buf, len, MSG_DONTWAIT);
58 * "MSG_DONTWAIT:
59 * Enables non-blocking operation; if the operation
60 * would block, EAGAIN is returned."
61 * but recv() works only for sockets!
62 *
63 * So far I don't see any good solution, I can only propose
64 * that affected readers should be careful and use this routine,
65 * which detects EAGAIN and uses poll() to wait on the fd.
66 * Thankfully, poll() doesn't care about O_NONBLOCK flag.
67 */
68ssize_t FAST_FUNC nonblock_safe_read(int fd, void *buf, size_t count)
69{
70 struct pollfd pfd[1];
71 ssize_t n;
72
73 while (1) {
74 n = safe_read(fd, buf, count);
75 if (n >= 0 || errno != EAGAIN)
76 return n;
77 /* fd is in O_NONBLOCK mode. Wait using poll and repeat */
78 pfd[0].fd = fd;
79 pfd[0].events = POLLIN;
80 safe_poll(pfd, 1, -1);
81 }
82}
83
84/* 22/*
85 * Read all of the supplied buffer from a file. 23 * Read all of the supplied buffer from a file.
86 * This does multiple reads as necessary. 24 * This does multiple reads as necessary.
@@ -115,60 +53,6 @@ ssize_t FAST_FUNC full_read(int fd, void *buf, size_t len)
115 return total; 53 return total;
116} 54}
117 55
118/* Die with an error message if we can't read the entire buffer. */
119void FAST_FUNC xread(int fd, void *buf, size_t count)
120{
121 if (count) {
122 ssize_t size = full_read(fd, buf, count);
123 if ((size_t)size != count)
124 bb_error_msg_and_die("short read");
125 }
126}
127
128/* Die with an error message if we can't read one character. */
129unsigned char FAST_FUNC xread_char(int fd)
130{
131 char tmp;
132 xread(fd, &tmp, 1);
133 return tmp;
134}
135
136// Reads one line a-la fgets (but doesn't save terminating '\n').
137// Reads byte-by-byte. Useful when it is important to not read ahead.
138// Bytes are appended to pfx (which must be malloced, or NULL).
139char* FAST_FUNC xmalloc_reads(int fd, char *buf, size_t *maxsz_p)
140{
141 char *p;
142 size_t sz = buf ? strlen(buf) : 0;
143 size_t maxsz = maxsz_p ? *maxsz_p : (INT_MAX - 4095);
144
145 goto jump_in;
146 while (sz < maxsz) {
147 if ((size_t)(p - buf) == sz) {
148 jump_in:
149 buf = xrealloc(buf, sz + 128);
150 p = buf + sz;
151 sz += 128;
152 }
153 /* nonblock_safe_read() because we are used by e.g. shells */
154 if (nonblock_safe_read(fd, p, 1) != 1) { /* EOF/error */
155 if (p == buf) { /* we read nothing */
156 free(buf);
157 return NULL;
158 }
159 break;
160 }
161 if (*p == '\n')
162 break;
163 p++;
164 }
165 *p = '\0';
166 if (maxsz_p)
167 *maxsz_p = p - buf;
168 p++;
169 return xrealloc(buf, p - buf);
170}
171
172ssize_t FAST_FUNC read_close(int fd, void *buf, size_t size) 56ssize_t FAST_FUNC read_close(int fd, void *buf, size_t size)
173{ 57{
174 /*int e;*/ 58 /*int e;*/
@@ -186,252 +70,3 @@ ssize_t FAST_FUNC open_read_close(const char *filename, void *buf, size_t size)
186 return fd; 70 return fd;
187 return read_close(fd, buf, size); 71 return read_close(fd, buf, size);
188} 72}
189
190
191// Read (potentially big) files in one go. File size is estimated
192// by stat. Extra '\0' byte is appended.
193void* FAST_FUNC xmalloc_read(int fd, size_t *maxsz_p)
194{
195 char *buf;
196 size_t size, rd_size, total;
197 size_t to_read;
198 struct stat st;
199
200 to_read = maxsz_p ? *maxsz_p : (INT_MAX - 4095); /* max to read */
201
202 /* Estimate file size */
203 st.st_size = 0; /* in case fstat fails, assume 0 */
204 fstat(fd, &st);
205 /* /proc/N/stat files report st_size 0 */
206 /* In order to make such files readable, we add small const */
207 size = (st.st_size | 0x3ff) + 1;
208
209 total = 0;
210 buf = NULL;
211 while (1) {
212 if (to_read < size)
213 size = to_read;
214 buf = xrealloc(buf, total + size + 1);
215 rd_size = full_read(fd, buf + total, size);
216 if ((ssize_t)rd_size == (ssize_t)(-1)) { /* error */
217 free(buf);
218 return NULL;
219 }
220 total += rd_size;
221 if (rd_size < size) /* EOF */
222 break;
223 if (to_read <= rd_size)
224 break;
225 to_read -= rd_size;
226 /* grow by 1/8, but in [1k..64k] bounds */
227 size = ((total / 8) | 0x3ff) + 1;
228 if (size > 64*1024)
229 size = 64*1024;
230 }
231 buf = xrealloc(buf, total + 1);
232 buf[total] = '\0';
233
234 if (maxsz_p)
235 *maxsz_p = total;
236 return buf;
237}
238
239#ifdef USING_LSEEK_TO_GET_SIZE
240/* Alternatively, file size can be obtained by lseek to the end.
241 * The code is slightly bigger. Retained in case fstat approach
242 * will not work for some weird cases (/proc, block devices, etc).
243 * (NB: lseek also can fail to work for some weird files) */
244
245// Read (potentially big) files in one go. File size is estimated by
246// lseek to end.
247void* FAST_FUNC xmalloc_open_read_close(const char *filename, size_t *maxsz_p)
248{
249 char *buf;
250 size_t size;
251 int fd;
252 off_t len;
253
254 fd = open(filename, O_RDONLY);
255 if (fd < 0)
256 return NULL;
257
258 /* /proc/N/stat files report len 0 here */
259 /* In order to make such files readable, we add small const */
260 size = 0x3ff; /* read only 1k on unseekable files */
261 len = lseek(fd, 0, SEEK_END) | 0x3ff; /* + up to 1k */
262 if (len != (off_t)-1) {
263 xlseek(fd, 0, SEEK_SET);
264 size = maxsz_p ? *maxsz_p : (INT_MAX - 4095);
265 if (len < size)
266 size = len;
267 }
268
269 buf = xmalloc(size + 1);
270 size = read_close(fd, buf, size);
271 if ((ssize_t)size < 0) {
272 free(buf);
273 return NULL;
274 }
275 buf = xrealloc(buf, size + 1);
276 buf[size] = '\0';
277
278 if (maxsz_p)
279 *maxsz_p = size;
280 return buf;
281}
282#endif
283
284// Read (potentially big) files in one go. File size is estimated
285// by stat.
286void* FAST_FUNC xmalloc_open_read_close(const char *filename, size_t *maxsz_p)
287{
288 char *buf;
289 int fd;
290
291 fd = open(filename, O_RDONLY);
292 if (fd < 0)
293 return NULL;
294
295 buf = xmalloc_read(fd, maxsz_p);
296 close(fd);
297 return buf;
298}
299
300void* FAST_FUNC xmalloc_xopen_read_close(const char *filename, size_t *maxsz_p)
301{
302 void *buf = xmalloc_open_read_close(filename, maxsz_p);
303 if (!buf)
304 bb_perror_msg_and_die("can't read '%s'", filename);
305 return buf;
306}
307
308/* Used by e.g. rpm which gives us a fd without filename,
309 * thus we can't guess the format from filename's extension.
310 */
311#if ZIPPED
312void FAST_FUNC setup_unzip_on_fd(int fd /*, int fail_if_not_detected*/)
313{
314 const int fail_if_not_detected = 1;
315 union {
316 uint8_t b[4];
317 uint16_t b16[2];
318 uint32_t b32[1];
319 } magic;
320 int offset = -2;
321# if BB_MMU
322 IF_DESKTOP(long long) int FAST_FUNC (*xformer)(int src_fd, int dst_fd);
323 enum { xformer_prog = 0 };
324# else
325 enum { xformer = 0 };
326 const char *xformer_prog;
327# endif
328
329 /* .gz and .bz2 both have 2-byte signature, and their
330 * unpack_XXX_stream wants this header skipped. */
331 xread(fd, magic.b16, sizeof(magic.b16));
332 if (ENABLE_FEATURE_SEAMLESS_GZ
333 && magic.b16[0] == GZIP_MAGIC
334 ) {
335# if BB_MMU
336 xformer = unpack_gz_stream;
337# else
338 xformer_prog = "gunzip";
339# endif
340 goto found_magic;
341 }
342 if (ENABLE_FEATURE_SEAMLESS_BZ2
343 && magic.b16[0] == BZIP2_MAGIC
344 ) {
345# if BB_MMU
346 xformer = unpack_bz2_stream;
347# else
348 xformer_prog = "bunzip2";
349# endif
350 goto found_magic;
351 }
352 if (ENABLE_FEATURE_SEAMLESS_XZ
353 && magic.b16[0] == XZ_MAGIC1
354 ) {
355 /* .xz signature: 0xfd, '7', 'z', 'X', 'Z', 0x00 */
356 /* More info at: http://tukaani.org/xz/xz-file-format.txt */
357 offset = -6;
358 xread(fd, magic.b32, sizeof(magic.b32));
359 if (magic.b32[0] == XZ_MAGIC2) {
360# if BB_MMU
361 xformer = unpack_xz_stream;
362 /* unpack_xz_stream wants fd at position 0 */
363 xlseek(fd, offset, SEEK_CUR);
364# else
365 xformer_prog = "unxz";
366# endif
367 goto found_magic;
368 }
369 }
370
371 /* No known magic seen */
372 if (fail_if_not_detected)
373 bb_error_msg_and_die("no gzip"
374 IF_FEATURE_SEAMLESS_BZ2("/bzip2")
375 IF_FEATURE_SEAMLESS_XZ("/xz")
376 " magic");
377 xlseek(fd, offset, SEEK_CUR);
378 return;
379
380 found_magic:
381# if !BB_MMU
382 /* NOMMU version of open_transformer execs
383 * an external unzipper that wants
384 * file position at the start of the file */
385 xlseek(fd, offset, SEEK_CUR);
386# endif
387 open_transformer(fd, xformer, xformer_prog);
388}
389#endif /* ZIPPED */
390
391int FAST_FUNC open_zipped(const char *fname)
392{
393#if !ZIPPED
394 return open(fname, O_RDONLY);
395#else
396 char *sfx;
397 int fd;
398
399 fd = open(fname, O_RDONLY);
400 if (fd < 0)
401 return fd;
402
403 sfx = strrchr(fname, '.');
404 if (sfx) {
405 sfx++;
406 if (ENABLE_FEATURE_SEAMLESS_LZMA && strcmp(sfx, "lzma") == 0)
407 /* .lzma has no header/signature, just trust it */
408 open_transformer(fd, unpack_lzma_stream, "unlzma");
409 else
410 if ((ENABLE_FEATURE_SEAMLESS_GZ && strcmp(sfx, "gz") == 0)
411 || (ENABLE_FEATURE_SEAMLESS_BZ2 && strcmp(sfx, "bz2") == 0)
412 || (ENABLE_FEATURE_SEAMLESS_XZ && strcmp(sfx, "xz") == 0)
413 ) {
414 setup_unzip_on_fd(fd /*, fail_if_not_detected: 1*/);
415 }
416 }
417
418 return fd;
419#endif
420}
421
422void* FAST_FUNC xmalloc_open_zipped_read_close(const char *fname, size_t *maxsz_p)
423{
424 int fd;
425 char *image;
426
427 fd = open_zipped(fname);
428 if (fd < 0)
429 return NULL;
430
431 image = xmalloc_read(fd, maxsz_p);
432 if (!image)
433 bb_perror_msg("read error from '%s'", fname);
434 close(fd);
435
436 return image;
437}
generated by cgit v1.2.3-55-g6feb (git 2.39.1) at 2025-08-13 12:49:43 +0000