1 bc7cb1a1 2003-11-23 devnull #include	<u.h>
  2 bc7cb1a1 2003-11-23 devnull #include	<libc.h>
  3 bc7cb1a1 2003-11-23 devnull #include	<ctype.h>
  4 bc7cb1a1 2003-11-23 devnull #include	<bio.h>
  5 bc7cb1a1 2003-11-23 devnull 
  6 bc7cb1a1 2003-11-23 devnull /*
  7 bc7cb1a1 2003-11-23 devnull  * tail command, posix plus v10 option -r.
  8 bc7cb1a1 2003-11-23 devnull  * the simple command tail -c, legal in v10, is illegal
  9 bc7cb1a1 2003-11-23 devnull  */
 10 bc7cb1a1 2003-11-23 devnull 
 11 b707cb51 2004-06-13 devnull vlong	count;
 12 bc7cb1a1 2003-11-23 devnull int	anycount;
 13 bc7cb1a1 2003-11-23 devnull int	follow;
 14 bc7cb1a1 2003-11-23 devnull int	file	= 0;
 15 bc7cb1a1 2003-11-23 devnull char*	umsg	= "usage: tail [-n N] [-c N] [-f] [-r] [+-N[bc][fr]] [file]";
 16 bc7cb1a1 2003-11-23 devnull 
 17 bc7cb1a1 2003-11-23 devnull Biobuf	bout;
 18 bc7cb1a1 2003-11-23 devnull enum
 19 bc7cb1a1 2003-11-23 devnull {
 20 bc7cb1a1 2003-11-23 devnull 	BEG,
 21 bc7cb1a1 2003-11-23 devnull 	END
 22 bc7cb1a1 2003-11-23 devnull } origin = END;
 23 bc7cb1a1 2003-11-23 devnull enum
 24 bc7cb1a1 2003-11-23 devnull {
 25 bc7cb1a1 2003-11-23 devnull 	CHARS,
 26 bc7cb1a1 2003-11-23 devnull 	LINES
 27 bc7cb1a1 2003-11-23 devnull } units = LINES;
 28 bc7cb1a1 2003-11-23 devnull enum
 29 bc7cb1a1 2003-11-23 devnull {
 30 bc7cb1a1 2003-11-23 devnull 	FWD,
 31 bc7cb1a1 2003-11-23 devnull 	REV
 32 bc7cb1a1 2003-11-23 devnull } dir = FWD;
 33 bc7cb1a1 2003-11-23 devnull 
 34 bc7cb1a1 2003-11-23 devnull extern	void	copy(void);
 35 bc7cb1a1 2003-11-23 devnull extern	void	fatal(char*);
 36 bc7cb1a1 2003-11-23 devnull extern	int	getnumber(char*);
 37 bc7cb1a1 2003-11-23 devnull extern	void	keep(void);
 38 bc7cb1a1 2003-11-23 devnull extern	void	reverse(void);
 39 bc7cb1a1 2003-11-23 devnull extern	void	skip(void);
 40 bc7cb1a1 2003-11-23 devnull extern	void	suffix(char*);
 41 bc7cb1a1 2003-11-23 devnull extern	long	tread(char*, long);
 42 cedbe4a4 2003-11-24 devnull #define trunc tailtrunc
 43 bc7cb1a1 2003-11-23 devnull extern	void	trunc(Dir*, Dir**);
 44 b707cb51 2004-06-13 devnull extern	vlong	tseek(vlong, int);
 45 bc7cb1a1 2003-11-23 devnull extern	void	twrite(char*, long);
 46 bc7cb1a1 2003-11-23 devnull extern	void	usage(void);
 47 bc7cb1a1 2003-11-23 devnull 
 48 bc7cb1a1 2003-11-23 devnull #define JUMP(o,p) tseek(o,p), copy()
 49 bc7cb1a1 2003-11-23 devnull 
 50 bc7cb1a1 2003-11-23 devnull void
 51 bc7cb1a1 2003-11-23 devnull main(int argc, char **argv)
 52 bc7cb1a1 2003-11-23 devnull {
 53 bc7cb1a1 2003-11-23 devnull 	int seekable, c;
 54 bc7cb1a1 2003-11-23 devnull 
 55 bc7cb1a1 2003-11-23 devnull 	Binit(&bout, 1, OWRITE);
 56 bc7cb1a1 2003-11-23 devnull 	for(; argc > 1 && ((c=*argv[1])=='-'||c=='+'); argc--,argv++ ) {
 57 bc7cb1a1 2003-11-23 devnull 		if(getnumber(argv[1])) {
 58 bc7cb1a1 2003-11-23 devnull 			suffix(argv[1]);
 59 bc7cb1a1 2003-11-23 devnull 			continue;
 60 bc7cb1a1 2003-11-23 devnull 		} else
 61 bc7cb1a1 2003-11-23 devnull 		if(c == '-')
 62 bc7cb1a1 2003-11-23 devnull 			switch(argv[1][1]) {
 63 bc7cb1a1 2003-11-23 devnull 			case 'c':
 64 bc7cb1a1 2003-11-23 devnull 				units = CHARS;
 65 bc7cb1a1 2003-11-23 devnull 			case 'n':
 66 bc7cb1a1 2003-11-23 devnull 				if(getnumber(argv[1]+2))
 67 bc7cb1a1 2003-11-23 devnull 					continue;
 68 bc7cb1a1 2003-11-23 devnull 				else
 69 bc7cb1a1 2003-11-23 devnull 				if(argc > 2 && getnumber(argv[2])) {
 70 bc7cb1a1 2003-11-23 devnull 					argc--, argv++;
 71 bc7cb1a1 2003-11-23 devnull 					continue;
 72 bc7cb1a1 2003-11-23 devnull 				} else
 73 bc7cb1a1 2003-11-23 devnull 					usage();
 74 bc7cb1a1 2003-11-23 devnull 			case 'r':
 75 bc7cb1a1 2003-11-23 devnull 				dir = REV;
 76 bc7cb1a1 2003-11-23 devnull 				continue;
 77 bc7cb1a1 2003-11-23 devnull 			case 'f':
 78 bc7cb1a1 2003-11-23 devnull 				follow++;
 79 bc7cb1a1 2003-11-23 devnull 				continue;
 80 bc7cb1a1 2003-11-23 devnull 			case '-':
 81 bc7cb1a1 2003-11-23 devnull 				argc--, argv++;
 82 bc7cb1a1 2003-11-23 devnull 			}
 83 bc7cb1a1 2003-11-23 devnull 		break;
 84 bc7cb1a1 2003-11-23 devnull 	}
 85 bc7cb1a1 2003-11-23 devnull 	if(dir==REV && (units==CHARS || follow || origin==BEG))
 86 bc7cb1a1 2003-11-23 devnull 		fatal("incompatible options");
 87 bc7cb1a1 2003-11-23 devnull 	if(!anycount)
 88 b707cb51 2004-06-13 devnull 		count = dir==REV? ~0ULL>>1: 10;
 89 bc7cb1a1 2003-11-23 devnull 	if(origin==BEG && units==LINES && count>0)
 90 bc7cb1a1 2003-11-23 devnull 		count--;
 91 bc7cb1a1 2003-11-23 devnull 	if(argc > 2)
 92 bc7cb1a1 2003-11-23 devnull 		usage();
 93 bc7cb1a1 2003-11-23 devnull 	if(argc > 1 && (file=open(argv[1],0)) < 0)
 94 bc7cb1a1 2003-11-23 devnull 		fatal(argv[1]);
 95 bc7cb1a1 2003-11-23 devnull 	seekable = seek(file,0L,0) == 0;
 96 bc7cb1a1 2003-11-23 devnull 
 97 bc7cb1a1 2003-11-23 devnull 	if(!seekable && origin==END)
 98 bc7cb1a1 2003-11-23 devnull 		keep();
 99 bc7cb1a1 2003-11-23 devnull 	else
100 bc7cb1a1 2003-11-23 devnull 	if(!seekable && origin==BEG)
101 bc7cb1a1 2003-11-23 devnull 		skip();
102 bc7cb1a1 2003-11-23 devnull 	else
103 bc7cb1a1 2003-11-23 devnull 	if(units==CHARS && origin==END)
104 bc7cb1a1 2003-11-23 devnull 		JUMP(-count, 2);
105 bc7cb1a1 2003-11-23 devnull 	else
106 bc7cb1a1 2003-11-23 devnull 	if(units==CHARS && origin==BEG)
107 bc7cb1a1 2003-11-23 devnull 		JUMP(count, 0);
108 bc7cb1a1 2003-11-23 devnull 	else
109 bc7cb1a1 2003-11-23 devnull 	if(units==LINES && origin==END)
110 bc7cb1a1 2003-11-23 devnull 		reverse();
111 bc7cb1a1 2003-11-23 devnull 	else
112 bc7cb1a1 2003-11-23 devnull 	if(units==LINES && origin==BEG)
113 bc7cb1a1 2003-11-23 devnull 		skip();
114 bc7cb1a1 2003-11-23 devnull 	if(follow && seekable)
115 bc7cb1a1 2003-11-23 devnull 		for(;;) {
116 bc7cb1a1 2003-11-23 devnull 			static Dir *sb0, *sb1;
117 bc7cb1a1 2003-11-23 devnull 			trunc(sb1, &sb0);
118 bc7cb1a1 2003-11-23 devnull 			copy();
119 bc7cb1a1 2003-11-23 devnull 			trunc(sb0, &sb1);
120 bc7cb1a1 2003-11-23 devnull 			sleep(5000);
121 bc7cb1a1 2003-11-23 devnull 		}
122 bc7cb1a1 2003-11-23 devnull 	exits(0);
123 bc7cb1a1 2003-11-23 devnull }
124 bc7cb1a1 2003-11-23 devnull 
125 bc7cb1a1 2003-11-23 devnull void
126 bc7cb1a1 2003-11-23 devnull trunc(Dir *old, Dir **new)
127 bc7cb1a1 2003-11-23 devnull {
128 bc7cb1a1 2003-11-23 devnull 	Dir *d;
129 b707cb51 2004-06-13 devnull 	vlong olength;
130 bc7cb1a1 2003-11-23 devnull 
131 bc7cb1a1 2003-11-23 devnull 	d = dirfstat(file);
132 bc7cb1a1 2003-11-23 devnull 	if(d == nil)
133 bc7cb1a1 2003-11-23 devnull 		return;
134 bc7cb1a1 2003-11-23 devnull 	olength = 0;
135 bc7cb1a1 2003-11-23 devnull 	if(old)
136 bc7cb1a1 2003-11-23 devnull 		olength = old->length;
137 bc7cb1a1 2003-11-23 devnull 	if(d->length < olength)
138 bc7cb1a1 2003-11-23 devnull 		d->length = tseek(0L, 0);
139 bc7cb1a1 2003-11-23 devnull 	free(*new);
140 bc7cb1a1 2003-11-23 devnull 	*new = d;
141 bc7cb1a1 2003-11-23 devnull }
142 bc7cb1a1 2003-11-23 devnull 
143 bc7cb1a1 2003-11-23 devnull void
144 bc7cb1a1 2003-11-23 devnull suffix(char *s)
145 bc7cb1a1 2003-11-23 devnull {
146 bc7cb1a1 2003-11-23 devnull 	while(*s && strchr("0123456789+-", *s))
147 bc7cb1a1 2003-11-23 devnull 		s++;
148 bc7cb1a1 2003-11-23 devnull 	switch(*s) {
149 bc7cb1a1 2003-11-23 devnull 	case 'b':
150 bc7cb1a1 2003-11-23 devnull 		if((count *= 1024) < 0)
151 bc7cb1a1 2003-11-23 devnull 			fatal("too big");
152 bc7cb1a1 2003-11-23 devnull 	case 'c':
153 bc7cb1a1 2003-11-23 devnull 		units = CHARS;
154 bc7cb1a1 2003-11-23 devnull 	case 'l':
155 bc7cb1a1 2003-11-23 devnull 		s++;
156 bc7cb1a1 2003-11-23 devnull 	}
157 bc7cb1a1 2003-11-23 devnull 	switch(*s) {
158 bc7cb1a1 2003-11-23 devnull 	case 'r':
159 bc7cb1a1 2003-11-23 devnull 		dir = REV;
160 bc7cb1a1 2003-11-23 devnull 		return;
161 bc7cb1a1 2003-11-23 devnull 	case 'f':
162 bc7cb1a1 2003-11-23 devnull 		follow++;
163 bc7cb1a1 2003-11-23 devnull 		return;
164 bc7cb1a1 2003-11-23 devnull 	case 0:
165 bc7cb1a1 2003-11-23 devnull 		return;
166 bc7cb1a1 2003-11-23 devnull 	}
167 bc7cb1a1 2003-11-23 devnull 	usage();
168 bc7cb1a1 2003-11-23 devnull }
169 bc7cb1a1 2003-11-23 devnull 
170 bc7cb1a1 2003-11-23 devnull /*
171 bc7cb1a1 2003-11-23 devnull  * read past head of the file to find tail
172 bc7cb1a1 2003-11-23 devnull  */
173 bc7cb1a1 2003-11-23 devnull void
174 bc7cb1a1 2003-11-23 devnull skip(void)
175 bc7cb1a1 2003-11-23 devnull {
176 bc7cb1a1 2003-11-23 devnull 	int i;
177 bc7cb1a1 2003-11-23 devnull 	long n;
178 bc7cb1a1 2003-11-23 devnull 	char buf[Bsize];
179 bc7cb1a1 2003-11-23 devnull 	if(units == CHARS) {
180 bc7cb1a1 2003-11-23 devnull 		for( ; count>0; count -=n) {
181 bc7cb1a1 2003-11-23 devnull 			n = count<Bsize? count: Bsize;
182 bc7cb1a1 2003-11-23 devnull 			if(!(n = tread(buf, n)))
183 bc7cb1a1 2003-11-23 devnull 				return;
184 bc7cb1a1 2003-11-23 devnull 		}
185 bc7cb1a1 2003-11-23 devnull 	} else /*units == LINES*/ {
186 bc7cb1a1 2003-11-23 devnull 		n = i = 0;
187 bc7cb1a1 2003-11-23 devnull 		while(count > 0) {
188 bc7cb1a1 2003-11-23 devnull 			if(!(n = tread(buf, Bsize)))
189 bc7cb1a1 2003-11-23 devnull 				return;
190 bc7cb1a1 2003-11-23 devnull 			for(i=0; i<n && count>0; i++)
191 bc7cb1a1 2003-11-23 devnull 				if(buf[i]=='\n')
192 bc7cb1a1 2003-11-23 devnull 					count--;
193 bc7cb1a1 2003-11-23 devnull 		}
194 bc7cb1a1 2003-11-23 devnull 		twrite(buf+i, n-i);
195 bc7cb1a1 2003-11-23 devnull 	}
196 bc7cb1a1 2003-11-23 devnull 	copy();
197 bc7cb1a1 2003-11-23 devnull }
198 bc7cb1a1 2003-11-23 devnull 
199 bc7cb1a1 2003-11-23 devnull void
200 bc7cb1a1 2003-11-23 devnull copy(void)
201 bc7cb1a1 2003-11-23 devnull {
202 bc7cb1a1 2003-11-23 devnull 	long n;
203 bc7cb1a1 2003-11-23 devnull 	char buf[Bsize];
204 bc7cb1a1 2003-11-23 devnull 	while((n=tread(buf, Bsize)) > 0) {
205 bc7cb1a1 2003-11-23 devnull 		twrite(buf, n);
206 bc7cb1a1 2003-11-23 devnull 		Bflush(&bout);	/* for FWD on pipe; else harmless */
207 bc7cb1a1 2003-11-23 devnull 	}
208 bc7cb1a1 2003-11-23 devnull }
209 bc7cb1a1 2003-11-23 devnull 
210 bc7cb1a1 2003-11-23 devnull /*
211 bc7cb1a1 2003-11-23 devnull  * read whole file, keeping the tail
212 bc7cb1a1 2003-11-23 devnull  *	complexity is length(file)*length(tail).
213 bc7cb1a1 2003-11-23 devnull  *	could be linear.
214 bc7cb1a1 2003-11-23 devnull  */
215 bc7cb1a1 2003-11-23 devnull void
216 bc7cb1a1 2003-11-23 devnull keep(void)
217 bc7cb1a1 2003-11-23 devnull {
218 bc7cb1a1 2003-11-23 devnull 	int len = 0;
219 bc7cb1a1 2003-11-23 devnull 	long bufsiz = 0;
220 bc7cb1a1 2003-11-23 devnull 	char *buf = 0;
221 bc7cb1a1 2003-11-23 devnull 	int j, k, n;
222 bc7cb1a1 2003-11-23 devnull 
223 bc7cb1a1 2003-11-23 devnull 	for(n=1; n;) {
224 bc7cb1a1 2003-11-23 devnull 		if(len+Bsize > bufsiz) {
225 bc7cb1a1 2003-11-23 devnull 			bufsiz += 2*Bsize;
226 bc7cb1a1 2003-11-23 devnull 			if(!(buf = realloc(buf, bufsiz+1)))
227 bc7cb1a1 2003-11-23 devnull 				fatal("out of space");
228 bc7cb1a1 2003-11-23 devnull 		}
229 bc7cb1a1 2003-11-23 devnull 		for(; n && len<bufsiz; len+=n)
230 bc7cb1a1 2003-11-23 devnull 			n = tread(buf+len, bufsiz-len);
231 bc7cb1a1 2003-11-23 devnull 		if(count >= len)
232 bc7cb1a1 2003-11-23 devnull 			continue;
233 bc7cb1a1 2003-11-23 devnull 		if(units == CHARS)
234 bc7cb1a1 2003-11-23 devnull 			j = len - count;
235 bc7cb1a1 2003-11-23 devnull 		else {
236 bc7cb1a1 2003-11-23 devnull 			/* units == LINES */
237 bc7cb1a1 2003-11-23 devnull 			j = buf[len-1]=='\n'? len-1: len;
238 bc7cb1a1 2003-11-23 devnull 			for(k=0; j>0; j--)
239 bc7cb1a1 2003-11-23 devnull 				if(buf[j-1] == '\n')
240 bc7cb1a1 2003-11-23 devnull 					if(++k >= count)
241 bc7cb1a1 2003-11-23 devnull 						break;
242 bc7cb1a1 2003-11-23 devnull 		}
243 bc7cb1a1 2003-11-23 devnull 		memmove(buf, buf+j, len-=j);
244 bc7cb1a1 2003-11-23 devnull 	}
245 bc7cb1a1 2003-11-23 devnull 	if(dir == REV) {
246 bc7cb1a1 2003-11-23 devnull 		if(len>0 && buf[len-1]!='\n')
247 bc7cb1a1 2003-11-23 devnull 			buf[len++] = '\n';
248 bc7cb1a1 2003-11-23 devnull 		for(j=len-1 ; j>0; j--)
249 bc7cb1a1 2003-11-23 devnull 			if(buf[j-1] == '\n') {
250 bc7cb1a1 2003-11-23 devnull 				twrite(buf+j, len-j);
251 bc7cb1a1 2003-11-23 devnull 				if(--count <= 0)
252 bc7cb1a1 2003-11-23 devnull 					return;
253 bc7cb1a1 2003-11-23 devnull 				len = j;
254 bc7cb1a1 2003-11-23 devnull 			}
255 bc7cb1a1 2003-11-23 devnull 	}
256 bc7cb1a1 2003-11-23 devnull 	if(count > 0)
257 bc7cb1a1 2003-11-23 devnull 		twrite(buf, len);
258 bc7cb1a1 2003-11-23 devnull }
259 bc7cb1a1 2003-11-23 devnull 
260 bc7cb1a1 2003-11-23 devnull /*
261 bc7cb1a1 2003-11-23 devnull  * count backward and print tail of file
262 bc7cb1a1 2003-11-23 devnull  */
263 bc7cb1a1 2003-11-23 devnull void
264 bc7cb1a1 2003-11-23 devnull reverse(void)
265 bc7cb1a1 2003-11-23 devnull {
266 bc7cb1a1 2003-11-23 devnull 	int first;
267 bc7cb1a1 2003-11-23 devnull 	long len = 0;
268 bc7cb1a1 2003-11-23 devnull 	long n = 0;
269 bc7cb1a1 2003-11-23 devnull 	long bufsiz = 0;
270 bc7cb1a1 2003-11-23 devnull 	char *buf = 0;
271 b707cb51 2004-06-13 devnull 	vlong pos = tseek(0L, 2);
272 bc7cb1a1 2003-11-23 devnull 
273 bc7cb1a1 2003-11-23 devnull 	for(first=1; pos>0 && count>0; first=0) {
274 bc7cb1a1 2003-11-23 devnull 		n = pos>Bsize? Bsize: (int)pos;
275 bc7cb1a1 2003-11-23 devnull 		pos -= n;
276 bc7cb1a1 2003-11-23 devnull 		if(len+n > bufsiz) {
277 bc7cb1a1 2003-11-23 devnull 			bufsiz += 2*Bsize;
278 bc7cb1a1 2003-11-23 devnull 			if(!(buf = realloc(buf, bufsiz+1)))
279 bc7cb1a1 2003-11-23 devnull 				fatal("out of space");
280 bc7cb1a1 2003-11-23 devnull 		}
281 bc7cb1a1 2003-11-23 devnull 		memmove(buf+n, buf, len);
282 bc7cb1a1 2003-11-23 devnull 		len += n;
283 bc7cb1a1 2003-11-23 devnull 		tseek(pos, 0);
284 bc7cb1a1 2003-11-23 devnull 		if(tread(buf, n) != n)
285 bc7cb1a1 2003-11-23 devnull 			fatal("length error");
286 bc7cb1a1 2003-11-23 devnull 		if(first && buf[len-1]!='\n')
287 bc7cb1a1 2003-11-23 devnull 			buf[len++] = '\n';
288 bc7cb1a1 2003-11-23 devnull 		for(n=len-1 ; n>0 && count>0; n--)
289 bc7cb1a1 2003-11-23 devnull 			if(buf[n-1] == '\n') {
290 bc7cb1a1 2003-11-23 devnull 				count--;
291 bc7cb1a1 2003-11-23 devnull 				if(dir == REV)
292 bc7cb1a1 2003-11-23 devnull 					twrite(buf+n, len-n);
293 bc7cb1a1 2003-11-23 devnull 				len = n;
294 bc7cb1a1 2003-11-23 devnull 			}
295 bc7cb1a1 2003-11-23 devnull 	}
296 bc7cb1a1 2003-11-23 devnull 	if(dir == FWD) {
297 bc7cb1a1 2003-11-23 devnull 		tseek(n==0? 0 : pos+n+1, 0);
298 bc7cb1a1 2003-11-23 devnull 		copy();
299 bc7cb1a1 2003-11-23 devnull 	} else
300 bc7cb1a1 2003-11-23 devnull 	if(count > 0)
301 bc7cb1a1 2003-11-23 devnull 		twrite(buf, len);
302 bc7cb1a1 2003-11-23 devnull }
303 bc7cb1a1 2003-11-23 devnull 
304 b707cb51 2004-06-13 devnull vlong
305 b707cb51 2004-06-13 devnull tseek(vlong o, int p)
306 bc7cb1a1 2003-11-23 devnull {
307 bc7cb1a1 2003-11-23 devnull 	o = seek(file, o, p);
308 bc7cb1a1 2003-11-23 devnull 	if(o == -1)
309 bc7cb1a1 2003-11-23 devnull 		fatal("");
310 bc7cb1a1 2003-11-23 devnull 	return o;
311 bc7cb1a1 2003-11-23 devnull }
312 bc7cb1a1 2003-11-23 devnull 
313 bc7cb1a1 2003-11-23 devnull long
314 bc7cb1a1 2003-11-23 devnull tread(char *buf, long n)
315 bc7cb1a1 2003-11-23 devnull {
316 bc7cb1a1 2003-11-23 devnull 	int r = read(file, buf, n);
317 bc7cb1a1 2003-11-23 devnull 	if(r == -1)
318 bc7cb1a1 2003-11-23 devnull 		fatal("");
319 bc7cb1a1 2003-11-23 devnull 	return r;
320 bc7cb1a1 2003-11-23 devnull }
321 bc7cb1a1 2003-11-23 devnull 
322 bc7cb1a1 2003-11-23 devnull void
323 bc7cb1a1 2003-11-23 devnull twrite(char *s, long n)
324 bc7cb1a1 2003-11-23 devnull {
325 bc7cb1a1 2003-11-23 devnull 	if(Bwrite(&bout, s, n) != n)
326 bc7cb1a1 2003-11-23 devnull 		fatal("");
327 bc7cb1a1 2003-11-23 devnull }
328 bc7cb1a1 2003-11-23 devnull 
329 bc7cb1a1 2003-11-23 devnull int
330 bc7cb1a1 2003-11-23 devnull getnumber(char *s)
331 bc7cb1a1 2003-11-23 devnull {
332 bc7cb1a1 2003-11-23 devnull 	if(*s=='-' || *s=='+')
333 bc7cb1a1 2003-11-23 devnull 		s++;
334 1c171e3a 2005-07-19 devnull 	if(!isdigit((uchar)*s))
335 bc7cb1a1 2003-11-23 devnull 		return 0;
336 bc7cb1a1 2003-11-23 devnull 	if(s[-1] == '+')
337 bc7cb1a1 2003-11-23 devnull 		origin = BEG;
338 bc7cb1a1 2003-11-23 devnull 	if(anycount++)
339 bc7cb1a1 2003-11-23 devnull 		fatal("excess option");
340 bc7cb1a1 2003-11-23 devnull 	count = atol(s);
341 bc7cb1a1 2003-11-23 devnull 
342 bc7cb1a1 2003-11-23 devnull 	/* check range of count */
343 1c171e3a 2005-07-19 devnull 	if(count < 0 || (int)count != count)
344 bc7cb1a1 2003-11-23 devnull 		fatal("too big");
345 bc7cb1a1 2003-11-23 devnull 	return 1;
346 fa325e9b 2020-01-10 cross }
347 bc7cb1a1 2003-11-23 devnull 
348 fa325e9b 2020-01-10 cross void
349 bc7cb1a1 2003-11-23 devnull fatal(char *s)
350 bc7cb1a1 2003-11-23 devnull {
351 bc7cb1a1 2003-11-23 devnull 	char buf[ERRMAX];
352 bc7cb1a1 2003-11-23 devnull 
353 bc7cb1a1 2003-11-23 devnull 	errstr(buf, sizeof buf);
354 bc7cb1a1 2003-11-23 devnull 	fprint(2, "tail: %s: %s\n", s, buf);
355 bc7cb1a1 2003-11-23 devnull 	exits(s);
356 bc7cb1a1 2003-11-23 devnull }
357 bc7cb1a1 2003-11-23 devnull 
358 bc7cb1a1 2003-11-23 devnull void
359 bc7cb1a1 2003-11-23 devnull usage(void)
360 bc7cb1a1 2003-11-23 devnull {
361 bc7cb1a1 2003-11-23 devnull 	fprint(2, "%s\n", umsg);
362 bc7cb1a1 2003-11-23 devnull 	exits("usage");
363 bc7cb1a1 2003-11-23 devnull }