Diff of /trunk/mkinitrd-magellan/busybox/coreutils/tail.c

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	revision 983 by niro, Fri Apr 24 18:33:46 2009 UTC	revision 984 by niro, Sun May 30 11:32:42 2010 UTC
#	Line 30  static const struct suffix_mult tail_suf	Line 30  static const struct suffix_mult tail_suf
30	{ "b", 512 },	{ "b", 512 },
31	{ "k", 1024 },	{ "k", 1024 },
32	{ "m", 1024*1024 },	{ "m", 1024*1024 },
33	{ }	{ "", 0 }
34	};	};
35
36	struct globals {	struct globals {
#	Line 50  static ssize_t tail_read(int fd, char *b	Line 50  static ssize_t tail_read(int fd, char *b
50	off_t current;	off_t current;
51	struct stat sbuf;	struct stat sbuf;
52
	/* (A good comment is missing here) */
	current = lseek(fd, 0, SEEK_CUR);
53	/* /proc files report zero st_size, don't lseek them. */	/* /proc files report zero st_size, don't lseek them. */
54	if (fstat(fd, &sbuf) == 0 && sbuf.st_size)	if (fstat(fd, &sbuf) == 0 && sbuf.st_size > 0) {
55		current = lseek(fd, 0, SEEK_CUR);
56	if (sbuf.st_size < current)	if (sbuf.st_size < current)
57	lseek(fd, 0, SEEK_SET);	xlseek(fd, 0, SEEK_SET);
58		}
59
60	r = full_read(fd, buf, count);	r = full_read(fd, buf, count);
61	if (r < 0) {	if (r < 0) {
#	Line 85  int tail_main(int argc, char **argv)	Line 85  int tail_main(int argc, char **argv)
85	unsigned count = 10;	unsigned count = 10;
86	unsigned sleep_period = 1;	unsigned sleep_period = 1;
87	bool from_top;	bool from_top;
	int header_threshhold = 1;
88	const char *str_c, *str_n;	const char *str_c, *str_n;
89
90	char *tailbuf;	char *tailbuf;
91	size_t tailbufsize;	size_t tailbufsize;
92	int taillen = 0;	unsigned header_threshhold = 1;
93	int newlines_seen = 0;	unsigned nfiles;
94	int nfiles, nread, nwrite, i, opt;	int i, opt;
	unsigned seen;
95
96	int *fds;	int *fds;
	char *s, *buf;
97	const char *fmt;	const char *fmt;
98
99	#if ENABLE_INCLUDE_SUSv2 || ENABLE_FEATURE_FANCY_TAIL	#if ENABLE_INCLUDE_SUSv2 || ENABLE_FEATURE_FANCY_TAIL
#	Line 110  int tail_main(int argc, char **argv)	Line 107  int tail_main(int argc, char **argv)
107	}	}
108	#endif	#endif
109
110	USE_FEATURE_FANCY_TAIL(opt_complementary = "s+";) /* -s N */	/* -s NUM, -F imlies -f */
111	opt = getopt32(argv, "fc:n:" USE_FEATURE_FANCY_TAIL("qs:v"),	IF_FEATURE_FANCY_TAIL(opt_complementary = "s+:Ff";)
112	&str_c, &str_n USE_FEATURE_FANCY_TAIL(,&sleep_period));	opt = getopt32(argv, "fc:n:" IF_FEATURE_FANCY_TAIL("qs:vF"),
113		&str_c, &str_n IF_FEATURE_FANCY_TAIL(,&sleep_period));
114	#define FOLLOW (opt & 0x1)	#define FOLLOW (opt & 0x1)
115	#define COUNT_BYTES (opt & 0x2)	#define COUNT_BYTES (opt & 0x2)
116	//if (opt & 0x1) // -f	//if (opt & 0x1) // -f
117	if (opt & 0x2) count = eat_num(str_c); // -c	if (opt & 0x2) count = eat_num(str_c); // -c
118	if (opt & 0x4) count = eat_num(str_n); // -n	if (opt & 0x4) count = eat_num(str_n); // -n
119	#if ENABLE_FEATURE_FANCY_TAIL	#if ENABLE_FEATURE_FANCY_TAIL
120	if (opt & 0x8) header_threshhold = INT_MAX; // -q	/* q: make it impossible for nfiles to be > header_threshhold */
121		if (opt & 0x8) header_threshhold = UINT_MAX; // -q
122		//if (opt & 0x10) // -s
123	if (opt & 0x20) header_threshhold = 0; // -v	if (opt & 0x20) header_threshhold = 0; // -v
124		# define FOLLOW_RETRY (opt & 0x40)
125		#else
126		# define FOLLOW_RETRY 0
127	#endif	#endif
128	argc -= optind;	argc -= optind;
129	argv += optind;	argv += optind;
#	Line 128  int tail_main(int argc, char **argv)	Line 131  int tail_main(int argc, char **argv)
131	G.status = EXIT_SUCCESS;	G.status = EXIT_SUCCESS;
132
133	/* open all the files */	/* open all the files */
134	fds = xmalloc(sizeof(int) * (argc + 1));	fds = xmalloc(sizeof(fds[0]) * (argc + 1));
135	if (!argv[0]) {	if (!argv[0]) {
136	struct stat statbuf;	struct stat statbuf;
137
138	if (!fstat(STDIN_FILENO, &statbuf) && S_ISFIFO(statbuf.st_mode)) {	if (fstat(STDIN_FILENO, &statbuf) == 0
139		&& S_ISFIFO(statbuf.st_mode)
140		) {
141	opt &= ~1; /* clear FOLLOW */	opt &= ~1; /* clear FOLLOW */
142	}	}
143	*argv = (char *) bb_msg_standard_input;	argv[0] = (char *) bb_msg_standard_input;
144	}	}
145	nfiles = i = 0;	nfiles = i = 0;
146	do {	do {
147	int fd = open_or_warn_stdin(argv[i]);	int fd = open_or_warn_stdin(argv[i]);
148	if (fd < 0) {	if (fd < 0 && !FOLLOW_RETRY) {
149	G.status = EXIT_FAILURE;	G.status = EXIT_FAILURE;
150	continue;	continue;
151	}	}
#	Line 161  int tail_main(int argc, char **argv)	Line 166  int tail_main(int argc, char **argv)
166	tailbuf = xmalloc(tailbufsize);	tailbuf = xmalloc(tailbufsize);
167
168	/* tail the files */	/* tail the files */
169	fmt = header_fmt + 1; /* Skip header leading newline on first output. */	fmt = header_fmt + 1; /* skip header leading newline on first output */
170	i = 0;	i = 0;
171	do {	do {
172		char *buf;
173		int taillen;
174		int newlines_seen;
175		unsigned seen;
176		int nread;
177		int fd = fds[i];
178
179		if (ENABLE_FEATURE_FANCY_TAIL && fd < 0)
180		continue; /* may happen with -E */
181
182	if (nfiles > header_threshhold) {	if (nfiles > header_threshhold) {
183	tail_xprint_header(fmt, argv[i]);	tail_xprint_header(fmt, argv[i]);
184	fmt = header_fmt;	fmt = header_fmt;
185	}	}
186
187	/* Optimizing count-bytes case if the file is seekable.	if (!from_top) {
188	* Beware of backing up too far.	off_t current = lseek(fd, 0, SEEK_END);
	* Also we exclude files with size 0 (because of /proc/xxx) */
	if (COUNT_BYTES && !from_top) {
	off_t current = lseek(fds[i], 0, SEEK_END);
189	if (current > 0) {	if (current > 0) {
190	if (count == 0)	unsigned off;
191	continue; /* showing zero lines is easy :) */	if (COUNT_BYTES) {
192	current -= count;	/* Optimizing count-bytes case if the file is seekable.
193		* Beware of backing up too far.
194		* Also we exclude files with size 0 (because of /proc/xxx) */
195		if (count == 0)
196		continue; /* showing zero bytes is easy :) */
197		current -= count;
198		if (current < 0)
199		current = 0;
200		xlseek(fd, current, SEEK_SET);
201		bb_copyfd_size(fd, STDOUT_FILENO, count);
202		continue;
203		}
204		#if 1 /* This is technically incorrect for *LONG* strings, but very useful */
205		/* Optimizing count-lines case if the file is seekable.
206		* We assume the lines are <64k.
207		* (Users complain that tail takes too long
208		* on multi-gigabyte files) */
209		off = (count | 0xf); /* for small counts, be more paranoid */
210		if (off > (INT_MAX / (64*1024)))
211		off = (INT_MAX / (64*1024));
212		current -= off * (64*1024);
213	if (current < 0)	if (current < 0)
214	current = 0;	current = 0;
215	xlseek(fds[i], current, SEEK_SET);	xlseek(fd, current, SEEK_SET);
216	bb_copyfd_size(fds[i], STDOUT_FILENO, count);	#endif
	continue;
217	}	}
218	}	}
219
220	buf = tailbuf;	buf = tailbuf;
221	taillen = 0;	taillen = 0;
222		/* "We saw 1st line/byte".
223		* Used only by +N code ("start from Nth", 1-based): */
224	seen = 1;	seen = 1;
225	newlines_seen = 0;	newlines_seen = 0;
226	while ((nread = tail_read(fds[i], buf, tailbufsize-taillen)) > 0) {	while ((nread = tail_read(fd, buf, tailbufsize-taillen)) > 0) {
227	if (from_top) {	if (from_top) {
228	nwrite = nread;	int nwrite = nread;
229	if (seen < count) {	if (seen < count) {
230		/* We need to skip a few more bytes/lines */
231	if (COUNT_BYTES) {	if (COUNT_BYTES) {
232	nwrite -= (count - seen);	nwrite -= (count - seen);
233	seen = count;	seen = count;
234	} else {	} else {
235	s = buf;	char *s = buf;
236	do {	do {
237	--nwrite;	--nwrite;
238	if (*s++ == '\n' && ++seen == count) {	if (*s++ == '\n' && ++seen == count) {
#	Line 207  int tail_main(int argc, char **argv)	Line 241  int tail_main(int argc, char **argv)
241	} while (nwrite);	} while (nwrite);
242	}	}
243	}	}
244	xwrite(STDOUT_FILENO, buf + nread - nwrite, nwrite);	if (nwrite > 0)
245		xwrite(STDOUT_FILENO, buf + nread - nwrite, nwrite);
246	} else if (count) {	} else if (count) {
247	if (COUNT_BYTES) {	if (COUNT_BYTES) {
248	taillen += nread;	taillen += nread;
#	Line 231  int tail_main(int argc, char **argv)	Line 266  int tail_main(int argc, char **argv)
266	taillen += nread;	taillen += nread;
267	} else {	} else {
268	int extra = (buf[nread-1] != '\n');	int extra = (buf[nread-1] != '\n');
269		char *s;
270
271	k = newlines_seen + newlines_in_buf + extra - count;	k = newlines_seen + newlines_in_buf + extra - count;
272	s = tailbuf;	s = tailbuf;
#	Line 257  int tail_main(int argc, char **argv)	Line 293  int tail_main(int argc, char **argv)
293	}	}
294	} while (++i < nfiles);	} while (++i < nfiles);
295
296	buf = xrealloc(tailbuf, BUFSIZ);	tailbuf = xrealloc(tailbuf, BUFSIZ);
297
298	fmt = NULL;	fmt = NULL;
299
300	if (FOLLOW) while (1) {	if (FOLLOW) while (1) {
301	sleep(sleep_period);	sleep(sleep_period);
302
303	i = 0;	i = 0;
304	do {	do {
305		int nread;
306		const char *filename = argv[i];
307		int fd = fds[i];
308
309		if (FOLLOW_RETRY) {
310		struct stat sbuf, fsbuf;
311
312		if (fd < 0
313		|| fstat(fd, &fsbuf) < 0
314		|| stat(filename, &sbuf) < 0
315		|| fsbuf.st_dev != sbuf.st_dev
316		|| fsbuf.st_ino != sbuf.st_ino
317		) {
318		int new_fd;
319
320		if (fd >= 0)
321		close(fd);
322		new_fd = open(filename, O_RDONLY);
323		if (new_fd >= 0) {
324		bb_error_msg("%s has %s; following end of new file",
325		filename, (fd < 0) ? "appeared" : "been replaced"
326		);
327		} else if (fd >= 0) {
328		bb_perror_msg("%s has become inaccessible", filename);
329		}
330		fds[i] = fd = new_fd;
331		}
332		}
333		if (ENABLE_FEATURE_FANCY_TAIL && fd < 0)
334		continue;
335	if (nfiles > header_threshhold) {	if (nfiles > header_threshhold) {
336	fmt = header_fmt;	fmt = header_fmt;
337	}	}
338	while ((nread = tail_read(fds[i], buf, BUFSIZ)) > 0) {	while ((nread = tail_read(fd, tailbuf, BUFSIZ)) > 0) {
339	if (fmt) {	if (fmt) {
340	tail_xprint_header(fmt, argv[i]);	tail_xprint_header(fmt, filename);
341	fmt = NULL;	fmt = NULL;
342	}	}
343	xwrite(STDOUT_FILENO, buf, nread);	xwrite(STDOUT_FILENO, tailbuf, nread);
344	}	}
345	} while (++i < nfiles);	} while (++i < nfiles);
346	}	}

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Legend: Removed from v.983   changed lines   Added in v.984