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d8ae9abd NW |
1 | /*- |
2 | * Copyright (c) 1991 The Regents of the University of California. | |
3 | * All rights reserved. | |
4 | * | |
5 | * This code is derived from software contributed to Berkeley by | |
6 | * Edward Sze-Tyan Wang. | |
7 | * | |
8 | * Redistribution and use in source and binary forms, with or without | |
9 | * modification, are permitted provided that the following conditions | |
10 | * are met: | |
11 | * 1. Redistributions of source code must retain the above copyright | |
12 | * notice, this list of conditions and the following disclaimer. | |
13 | * 2. Redistributions in binary form must reproduce the above copyright | |
14 | * notice, this list of conditions and the following disclaimer in the | |
15 | * documentation and/or other materials provided with the distribution. | |
16 | * 3. All advertising materials mentioning features or use of this software | |
17 | * must display the following acknowledgement: | |
18 | * This product includes software developed by the University of | |
19 | * California, Berkeley and its contributors. | |
20 | * 4. Neither the name of the University nor the names of its contributors | |
21 | * may be used to endorse or promote products derived from this software | |
22 | * without specific prior written permission. | |
23 | * | |
24 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
25 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
26 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
27 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
28 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
29 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
30 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
31 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
32 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
33 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
34 | * SUCH DAMAGE. | |
35 | */ | |
36 | ||
37 | #ifndef lint | |
38 | char copyright[] = | |
39 | "@(#) Copyright (c) 1991 The Regents of the University of California.\n\ | |
40 | All rights reserved.\n"; | |
41 | #endif /* not lint */ | |
42 | ||
43 | #ifndef lint | |
44 | static char sccsid[] = "@(#)tail.c 5.7 (Berkeley) 2/12/92"; | |
45 | #endif /* not lint */ | |
15637ed4 | 46 | |
15637ed4 | 47 | #include <sys/types.h> |
15637ed4 | 48 | #include <sys/stat.h> |
d8ae9abd | 49 | #include <errno.h> |
15637ed4 | 50 | #include <unistd.h> |
d8ae9abd NW |
51 | #include <stdio.h> |
52 | #include <stdlib.h> | |
15637ed4 | 53 | #include <string.h> |
d8ae9abd | 54 | #include "extern.h" |
15637ed4 | 55 | |
d8ae9abd NW |
56 | int fflag, rflag, rval; |
57 | char *fname; | |
15637ed4 | 58 | |
d8ae9abd NW |
59 | static void obsolete __P((char **)); |
60 | static void usage __P((void)); | |
15637ed4 | 61 | |
d8ae9abd NW |
62 | main(argc, argv) |
63 | int argc; | |
64 | char **argv; | |
15637ed4 | 65 | { |
d8ae9abd NW |
66 | struct stat sb; |
67 | FILE *fp; | |
68 | long off; | |
69 | enum STYLE style; | |
70 | int ch; | |
71 | char *p; | |
72 | ||
73 | /* | |
74 | * Tail's options are weird. First, -n10 is the same as -n-10, not | |
75 | * -n+10. Second, the number options are 1 based and not offsets, | |
76 | * so -n+1 is the first line, and -c-1 is the last byte. Third, the | |
77 | * number options for the -r option specify the number of things that | |
78 | * get displayed, not the starting point in the file. The one major | |
79 | * incompatibility in this version as compared to historical versions | |
80 | * is that the 'r' option couldn't be modified by the -lbc options, | |
81 | * i.e. it was always done in lines. This version treats -rc as a | |
82 | * number of characters in reverse order. Finally, the default for | |
83 | * -r is the entire file, not 10 lines. | |
84 | */ | |
85 | #define ARG(units, forward, backward) { \ | |
86 | if (style) \ | |
87 | usage(); \ | |
88 | off = strtol(optarg, &p, 10) * (units); \ | |
89 | if (*p) \ | |
90 | err("illegal offset -- %s", optarg); \ | |
91 | switch(optarg[0]) { \ | |
92 | case '+': \ | |
93 | if (off) \ | |
94 | off -= (units); \ | |
95 | style = (forward); \ | |
96 | break; \ | |
97 | case '-': \ | |
98 | off = -off; \ | |
99 | /* FALLTHROUGH */ \ | |
100 | default: \ | |
101 | style = (backward); \ | |
102 | break; \ | |
103 | } \ | |
104 | } | |
15637ed4 | 105 | |
d8ae9abd NW |
106 | obsolete(argv); |
107 | style = NOTSET; | |
108 | while ((ch = getopt(argc, argv, "b:c:fn:r")) != EOF) | |
109 | switch(ch) { | |
15637ed4 | 110 | case 'b': |
d8ae9abd NW |
111 | ARG(512, FBYTES, RBYTES); |
112 | break; | |
15637ed4 | 113 | case 'c': |
d8ae9abd NW |
114 | ARG(1, FBYTES, RBYTES); |
115 | break; | |
15637ed4 | 116 | case 'f': |
d8ae9abd NW |
117 | fflag = 1; |
118 | break; | |
119 | case 'n': | |
120 | ARG(1, FLINES, RLINES); | |
121 | break; | |
122 | case 'r': | |
123 | rflag = 1; | |
124 | break; | |
125 | case '?': | |
15637ed4 | 126 | default: |
d8ae9abd | 127 | usage(); |
15637ed4 | 128 | } |
d8ae9abd NW |
129 | argc -= optind; |
130 | argv += optind; | |
131 | ||
132 | /* | |
133 | * If displaying in reverse, don't permit follow option, and convert | |
134 | * style values. | |
135 | */ | |
136 | if (rflag) { | |
137 | if (fflag) | |
138 | usage(); | |
139 | if (style == FBYTES) | |
140 | style = RBYTES; | |
141 | if (style == FLINES) | |
142 | style = RLINES; | |
15637ed4 | 143 | } |
15637ed4 | 144 | |
d8ae9abd NW |
145 | /* |
146 | * If style not specified, the default is the whole file for -r, and | |
147 | * the last 10 lines if not -r. | |
148 | */ | |
149 | if (style == NOTSET) | |
150 | if (rflag) { | |
151 | off = 0; | |
152 | style = REVERSE; | |
153 | } else { | |
154 | off = 10; | |
155 | style = RLINES; | |
156 | } | |
15637ed4 | 157 | |
d8ae9abd NW |
158 | if (fname = *argv) { |
159 | if ((fp = fopen(fname, "r")) == NULL) | |
160 | ierr(); | |
161 | } else { | |
162 | fp = stdin; | |
163 | fname = "stdin"; | |
15637ed4 | 164 | } |
15637ed4 | 165 | |
d8ae9abd NW |
166 | if (fstat(fileno(fp), &sb)) |
167 | ierr(); | |
15637ed4 | 168 | |
d8ae9abd NW |
169 | /* |
170 | * Determine if input is a pipe. 4.4BSD will set the SOCKET | |
171 | * bit in the st_mode field for pipes. Fix this then. | |
172 | */ | |
173 | if (lseek(fileno(fp), 0L, SEEK_CUR) == -1 && errno == ESPIPE) { | |
174 | errno = 0; | |
175 | fflag = 0; /* POSIX.2 requires this. */ | |
15637ed4 | 176 | } |
15637ed4 | 177 | |
d8ae9abd NW |
178 | if (rflag) |
179 | reverse(fp, style, off, &sb); | |
180 | else | |
181 | forward(fp, style, off, &sb); | |
182 | exit(rval); | |
15637ed4 RG |
183 | } |
184 | ||
d8ae9abd NW |
185 | /* |
186 | * Convert the obsolete argument form into something that getopt can handle. | |
187 | * This means that anything of the form [+-][0-9][0-9]*[lbc][fr] that isn't | |
188 | * the option argument for a -b, -c or -n option gets converted. | |
189 | */ | |
190 | static void | |
191 | obsolete(argv) | |
192 | char **argv; | |
15637ed4 | 193 | { |
d8ae9abd NW |
194 | register char *ap, *p, *t; |
195 | int len; | |
196 | char *start; | |
197 | ||
198 | while (ap = *++argv) { | |
199 | /* Return if "--" or not an option of any form. */ | |
200 | if (ap[0] != '-') { | |
201 | if (ap[0] != '+') | |
202 | return; | |
203 | } else if (ap[1] == '-') | |
204 | return; | |
205 | ||
206 | switch(*++ap) { | |
207 | /* Old-style option. */ | |
208 | case '0': case '1': case '2': case '3': case '4': | |
209 | case '5': case '6': case '7': case '8': case '9': | |
210 | ||
211 | /* Malloc space for dash, new option and argument. */ | |
212 | len = strlen(*argv); | |
213 | if ((start = p = malloc(len + 3)) == NULL) | |
214 | err("%s", strerror(errno)); | |
215 | *p++ = '-'; | |
216 | ||
217 | /* | |
218 | * Go to the end of the option argument. Save off any | |
219 | * trailing options (-3lf) and translate any trailing | |
220 | * output style characters. | |
221 | */ | |
222 | t = *argv + len - 1; | |
223 | if (*t == 'f' || *t == 'r') { | |
224 | *p++ = *t; | |
225 | *t-- = '\0'; | |
226 | } | |
227 | switch(*t) { | |
228 | case 'b': | |
229 | *p++ = 'b'; | |
230 | *t = '\0'; | |
231 | break; | |
232 | case 'c': | |
233 | *p++ = 'c'; | |
234 | *t = '\0'; | |
235 | break; | |
236 | case 'l': | |
237 | *t = '\0'; | |
238 | /* FALLTHROUGH */ | |
239 | case '0': case '1': case '2': case '3': case '4': | |
240 | case '5': case '6': case '7': case '8': case '9': | |
241 | *p++ = 'n'; | |
242 | break; | |
243 | default: | |
244 | err("illegal option -- %s", *argv); | |
245 | } | |
246 | *p++ = *argv[0]; | |
247 | (void)strcpy(p, ap); | |
248 | *argv = start; | |
249 | continue; | |
250 | ||
251 | /* | |
252 | * Options w/ arguments, skip the argument and continue | |
253 | * with the next option. | |
254 | */ | |
255 | case 'b': | |
256 | case 'c': | |
257 | case 'n': | |
258 | if (!ap[1]) | |
259 | ++argv; | |
260 | /* FALLTHROUGH */ | |
261 | /* Options w/o arguments, continue with the next option. */ | |
262 | case 'f': | |
263 | case 'r': | |
264 | continue; | |
15637ed4 | 265 | |
d8ae9abd NW |
266 | /* Illegal option, return and let getopt handle it. */ |
267 | default: | |
268 | return; | |
269 | } | |
15637ed4 | 270 | } |
15637ed4 RG |
271 | } |
272 | ||
d8ae9abd NW |
273 | static void |
274 | usage() | |
15637ed4 | 275 | { |
d8ae9abd NW |
276 | (void)fprintf(stderr, |
277 | "usage: tail [-f | -r] [-b # | -c # | -n #] [file]\n"); | |
278 | exit(1); | |
15637ed4 | 279 | } |