24 |
* 7) lseek attempted when count==0 even if arg was +0 (from top) |
* 7) lseek attempted when count==0 even if arg was +0 (from top) |
25 |
*/ |
*/ |
26 |
|
|
27 |
#include "busybox.h" |
#include "libbb.h" |
28 |
|
|
29 |
static const struct suffix_mult tail_suffixes[] = { |
static const struct suffix_mult tail_suffixes[] = { |
30 |
{ "b", 512 }, |
{ "b", 512 }, |
31 |
{ "k", 1024 }, |
{ "k", 1024 }, |
32 |
{ "m", 1024*1024 }, |
{ "m", 1024*1024 }, |
33 |
{ NULL, 0 } |
{ } |
34 |
}; |
}; |
35 |
|
|
36 |
static int status; |
struct globals { |
37 |
|
bool status; |
38 |
|
}; |
39 |
|
#define G (*(struct globals*)&bb_common_bufsiz1) |
40 |
|
|
41 |
static void tail_xprint_header(const char *fmt, const char *filename) |
static void tail_xprint_header(const char *fmt, const char *filename) |
42 |
{ |
{ |
47 |
static ssize_t tail_read(int fd, char *buf, size_t count) |
static ssize_t tail_read(int fd, char *buf, size_t count) |
48 |
{ |
{ |
49 |
ssize_t r; |
ssize_t r; |
50 |
off_t current, end; |
off_t current; |
51 |
struct stat sbuf; |
struct stat sbuf; |
52 |
|
|
53 |
end = current = lseek(fd, 0, SEEK_CUR); |
/* (A good comment is missing here) */ |
54 |
if (!fstat(fd, &sbuf)) |
current = lseek(fd, 0, SEEK_CUR); |
55 |
end = sbuf.st_size; |
/* /proc files report zero st_size, don't lseek them. */ |
56 |
lseek(fd, end < current ? 0 : current, SEEK_SET); |
if (fstat(fd, &sbuf) == 0 && sbuf.st_size) |
57 |
r = safe_read(fd, buf, count); |
if (sbuf.st_size < current) |
58 |
|
lseek(fd, 0, SEEK_SET); |
59 |
|
|
60 |
|
r = full_read(fd, buf, count); |
61 |
if (r < 0) { |
if (r < 0) { |
62 |
bb_perror_msg(bb_msg_read_error); |
bb_perror_msg(bb_msg_read_error); |
63 |
status = EXIT_FAILURE; |
G.status = EXIT_FAILURE; |
64 |
} |
} |
65 |
|
|
66 |
return r; |
return r; |
67 |
} |
} |
68 |
|
|
69 |
static const char header_fmt[] = "\n==> %s <==\n"; |
static const char header_fmt[] ALIGN1 = "\n==> %s <==\n"; |
70 |
|
|
71 |
|
static unsigned eat_num(const char *p) |
72 |
|
{ |
73 |
|
if (*p == '-') |
74 |
|
p++; |
75 |
|
else if (*p == '+') { |
76 |
|
p++; |
77 |
|
G.status = 1; /* mark that we saw "+" */ |
78 |
|
} |
79 |
|
return xatou_sfx(p, tail_suffixes); |
80 |
|
} |
81 |
|
|
82 |
|
int tail_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
83 |
int tail_main(int argc, char **argv) |
int tail_main(int argc, char **argv) |
84 |
{ |
{ |
85 |
unsigned count = 10; |
unsigned count = 10; |
86 |
unsigned sleep_period = 1; |
unsigned sleep_period = 1; |
87 |
int from_top = 0; |
bool from_top; |
88 |
int header_threshhold = 1; |
int header_threshhold = 1; |
89 |
const char *str_c, *str_n, *str_s; |
const char *str_c, *str_n; |
90 |
|
|
91 |
char *tailbuf; |
char *tailbuf; |
92 |
size_t tailbufsize; |
size_t tailbufsize; |
93 |
int taillen = 0; |
int taillen = 0; |
94 |
int newline = 0; |
int newlines_seen = 0; |
95 |
int nfiles, nread, nwrite, seen, i, opt; |
int nfiles, nread, nwrite, i, opt; |
96 |
|
unsigned seen; |
97 |
|
|
98 |
int *fds; |
int *fds; |
99 |
char *s, *buf; |
char *s, *buf; |
100 |
const char *fmt; |
const char *fmt; |
101 |
|
|
|
void eat_num(const char *p) { |
|
|
if (*p == '-') p++; |
|
|
else if (*p == '+') { p++; from_top = 1; } |
|
|
count = xatou_sfx(p, tail_suffixes); |
|
|
} |
|
|
|
|
|
|
|
102 |
#if ENABLE_INCLUDE_SUSv2 || ENABLE_FEATURE_FANCY_TAIL |
#if ENABLE_INCLUDE_SUSv2 || ENABLE_FEATURE_FANCY_TAIL |
103 |
/* Allow legacy syntax of an initial numeric option without -n. */ |
/* Allow legacy syntax of an initial numeric option without -n. */ |
104 |
if (argc >= 2 && (argv[1][0] == '+' || argv[1][0] == '-') |
if (argv[1] && (argv[1][0] == '+' || argv[1][0] == '-') |
105 |
&& isdigit(argv[1][1]) |
&& isdigit(argv[1][1]) |
106 |
) { |
) { |
107 |
argv[0] = "-n"; |
count = eat_num(argv[1]); |
108 |
argv--; |
argv++; |
109 |
argc++; |
argc--; |
110 |
} |
} |
111 |
#endif |
#endif |
112 |
|
|
113 |
opt = getopt32(argc, argv, "fc:n:" USE_FEATURE_FANCY_TAIL("qs:v"), &str_c, &str_n, &str_s); |
USE_FEATURE_FANCY_TAIL(opt_complementary = "s+";) /* -s N */ |
114 |
|
opt = getopt32(argv, "fc:n:" USE_FEATURE_FANCY_TAIL("qs:v"), |
115 |
|
&str_c, &str_n USE_FEATURE_FANCY_TAIL(,&sleep_period)); |
116 |
#define FOLLOW (opt & 0x1) |
#define FOLLOW (opt & 0x1) |
117 |
#define COUNT_BYTES (opt & 0x2) |
#define COUNT_BYTES (opt & 0x2) |
118 |
//if (opt & 0x1) // -f |
//if (opt & 0x1) // -f |
119 |
if (opt & 0x2) eat_num(str_c); // -c |
if (opt & 0x2) count = eat_num(str_c); // -c |
120 |
if (opt & 0x4) eat_num(str_n); // -n |
if (opt & 0x4) count = eat_num(str_n); // -n |
121 |
#if ENABLE_FEATURE_FANCY_TAIL |
#if ENABLE_FEATURE_FANCY_TAIL |
122 |
if (opt & 0x8) header_threshhold = INT_MAX; // -q |
if (opt & 0x8) header_threshhold = INT_MAX; // -q |
|
if (opt & 0x10) sleep_period = xatou(str_s); // -s |
|
123 |
if (opt & 0x20) header_threshhold = 0; // -v |
if (opt & 0x20) header_threshhold = 0; // -v |
124 |
#endif |
#endif |
125 |
argc -= optind; |
argc -= optind; |
126 |
argv += optind; |
argv += optind; |
127 |
|
from_top = G.status; /* 1 if there was "-c +N" or "-n +N" */ |
128 |
|
G.status = EXIT_SUCCESS; |
129 |
|
|
130 |
/* open all the files */ |
/* open all the files */ |
131 |
fds = xmalloc(sizeof(int) * (argc + 1)); |
fds = xmalloc(sizeof(int) * (argc + 1)); |
132 |
nfiles = i = 0; |
if (!argv[0]) { |
|
if (argc == 0) { |
|
133 |
struct stat statbuf; |
struct stat statbuf; |
134 |
|
|
135 |
if (!fstat(STDIN_FILENO, &statbuf) && S_ISFIFO(statbuf.st_mode)) { |
if (!fstat(STDIN_FILENO, &statbuf) && S_ISFIFO(statbuf.st_mode)) { |
136 |
opt &= ~1; /* clear FOLLOW */ |
opt &= ~1; /* clear FOLLOW */ |
137 |
} |
} |
138 |
*argv = (char *) bb_msg_standard_input; |
*argv = (char *) bb_msg_standard_input; |
|
goto DO_STDIN; |
|
139 |
} |
} |
140 |
|
nfiles = i = 0; |
141 |
do { |
do { |
142 |
if (NOT_LONE_DASH(argv[i])) { |
int fd = open_or_warn_stdin(argv[i]); |
143 |
fds[nfiles] = open(argv[i], O_RDONLY); |
if (fd < 0) { |
144 |
if (fds[nfiles] < 0) { |
G.status = EXIT_FAILURE; |
145 |
bb_perror_msg("%s", argv[i]); |
continue; |
|
status = EXIT_FAILURE; |
|
|
continue; |
|
|
} |
|
|
} else { |
|
|
DO_STDIN: /* "-" */ |
|
|
fds[nfiles] = STDIN_FILENO; |
|
146 |
} |
} |
147 |
argv[nfiles] = argv[i]; |
fds[nfiles] = fd; |
148 |
++nfiles; |
argv[nfiles++] = argv[i]; |
149 |
} while (++i < argc); |
} while (++i < argc); |
150 |
|
|
151 |
if (!nfiles) |
if (!nfiles) |
152 |
bb_error_msg_and_die("no files"); |
bb_error_msg_and_die("no files"); |
153 |
|
|
154 |
|
/* prepare the buffer */ |
155 |
tailbufsize = BUFSIZ; |
tailbufsize = BUFSIZ; |
|
|
|
|
/* tail the files */ |
|
156 |
if (!from_top && COUNT_BYTES) { |
if (!from_top && COUNT_BYTES) { |
157 |
if (tailbufsize < count) { |
if (tailbufsize < count + BUFSIZ) { |
158 |
tailbufsize = count + BUFSIZ; |
tailbufsize = count + BUFSIZ; |
159 |
} |
} |
160 |
} |
} |
161 |
|
tailbuf = xmalloc(tailbufsize); |
162 |
|
|
163 |
buf = tailbuf = xmalloc(tailbufsize); |
/* tail the files */ |
|
|
|
164 |
fmt = header_fmt + 1; /* Skip header leading newline on first output. */ |
fmt = header_fmt + 1; /* Skip header leading newline on first output. */ |
165 |
i = 0; |
i = 0; |
166 |
do { |
do { |
|
/* Be careful. It would be possible to optimize the count-bytes |
|
|
* case if the file is seekable. If you do though, remember that |
|
|
* starting file position may not be the beginning of the file. |
|
|
* Beware of backing up too far. See example in wc.c. |
|
|
*/ |
|
|
if (!(count | from_top) && lseek(fds[i], 0, SEEK_END) >= 0) { |
|
|
continue; |
|
|
} |
|
|
|
|
167 |
if (nfiles > header_threshhold) { |
if (nfiles > header_threshhold) { |
168 |
tail_xprint_header(fmt, argv[i]); |
tail_xprint_header(fmt, argv[i]); |
169 |
fmt = header_fmt; |
fmt = header_fmt; |
170 |
} |
} |
171 |
|
|
172 |
|
/* Optimizing count-bytes case if the file is seekable. |
173 |
|
* Beware of backing up too far. |
174 |
|
* Also we exclude files with size 0 (because of /proc/xxx) */ |
175 |
|
if (COUNT_BYTES && !from_top) { |
176 |
|
off_t current = lseek(fds[i], 0, SEEK_END); |
177 |
|
if (current > 0) { |
178 |
|
if (count == 0) |
179 |
|
continue; /* showing zero lines is easy :) */ |
180 |
|
current -= count; |
181 |
|
if (current < 0) |
182 |
|
current = 0; |
183 |
|
xlseek(fds[i], current, SEEK_SET); |
184 |
|
bb_copyfd_size(fds[i], STDOUT_FILENO, count); |
185 |
|
continue; |
186 |
|
} |
187 |
|
} |
188 |
|
|
189 |
buf = tailbuf; |
buf = tailbuf; |
190 |
taillen = 0; |
taillen = 0; |
191 |
seen = 1; |
seen = 1; |
192 |
newline = 0; |
newlines_seen = 0; |
|
|
|
193 |
while ((nread = tail_read(fds[i], buf, tailbufsize-taillen)) > 0) { |
while ((nread = tail_read(fds[i], buf, tailbufsize-taillen)) > 0) { |
194 |
if (from_top) { |
if (from_top) { |
195 |
nwrite = nread; |
nwrite = nread; |
211 |
} else if (count) { |
} else if (count) { |
212 |
if (COUNT_BYTES) { |
if (COUNT_BYTES) { |
213 |
taillen += nread; |
taillen += nread; |
214 |
if (taillen > count) { |
if (taillen > (int)count) { |
215 |
memmove(tailbuf, tailbuf + taillen - count, count); |
memmove(tailbuf, tailbuf + taillen - count, count); |
216 |
taillen = count; |
taillen = count; |
217 |
} |
} |
218 |
} else { |
} else { |
219 |
int k = nread; |
int k = nread; |
220 |
int nbuf = 0; |
int newlines_in_buf = 0; |
221 |
|
|
222 |
while (k) { |
do { /* count '\n' in last read */ |
223 |
--k; |
k--; |
224 |
if (buf[k] == '\n') { |
if (buf[k] == '\n') { |
225 |
++nbuf; |
newlines_in_buf++; |
226 |
} |
} |
227 |
} |
} while (k); |
228 |
|
|
229 |
if (newline + nbuf < count) { |
if (newlines_seen + newlines_in_buf < (int)count) { |
230 |
newline += nbuf; |
newlines_seen += newlines_in_buf; |
231 |
taillen += nread; |
taillen += nread; |
|
|
|
232 |
} else { |
} else { |
233 |
int extra = 0; |
int extra = (buf[nread-1] != '\n'); |
|
if (buf[nread-1] != '\n') { |
|
|
extra = 1; |
|
|
} |
|
234 |
|
|
235 |
k = newline + nbuf + extra - count; |
k = newlines_seen + newlines_in_buf + extra - count; |
236 |
s = tailbuf; |
s = tailbuf; |
237 |
while (k) { |
while (k) { |
238 |
if (*s == '\n') { |
if (*s == '\n') { |
239 |
--k; |
k--; |
240 |
} |
} |
241 |
++s; |
s++; |
242 |
} |
} |
|
|
|
243 |
taillen += nread - (s - tailbuf); |
taillen += nread - (s - tailbuf); |
244 |
memmove(tailbuf, s, taillen); |
memmove(tailbuf, s, taillen); |
245 |
newline = count - extra; |
newlines_seen = count - extra; |
246 |
} |
} |
247 |
if (tailbufsize < taillen + BUFSIZ) { |
if (tailbufsize < (size_t)taillen + BUFSIZ) { |
248 |
tailbufsize = taillen + BUFSIZ; |
tailbufsize = taillen + BUFSIZ; |
249 |
tailbuf = xrealloc(tailbuf, tailbufsize); |
tailbuf = xrealloc(tailbuf, tailbufsize); |
250 |
} |
} |
251 |
} |
} |
252 |
buf = tailbuf + taillen; |
buf = tailbuf + taillen; |
253 |
} |
} |
254 |
} |
} /* while (tail_read() > 0) */ |
|
|
|
255 |
if (!from_top) { |
if (!from_top) { |
256 |
xwrite(STDOUT_FILENO, tailbuf, taillen); |
xwrite(STDOUT_FILENO, tailbuf, taillen); |
257 |
} |
} |
|
|
|
|
taillen = 0; |
|
258 |
} while (++i < nfiles); |
} while (++i < nfiles); |
259 |
|
|
260 |
buf = xrealloc(tailbuf, BUFSIZ); |
buf = xrealloc(tailbuf, BUFSIZ); |
268 |
if (nfiles > header_threshhold) { |
if (nfiles > header_threshhold) { |
269 |
fmt = header_fmt; |
fmt = header_fmt; |
270 |
} |
} |
271 |
while ((nread = tail_read(fds[i], buf, sizeof(buf))) > 0) { |
while ((nread = tail_read(fds[i], buf, BUFSIZ)) > 0) { |
272 |
if (fmt) { |
if (fmt) { |
273 |
tail_xprint_header(fmt, argv[i]); |
tail_xprint_header(fmt, argv[i]); |
274 |
fmt = NULL; |
fmt = NULL; |
277 |
} |
} |
278 |
} while (++i < nfiles); |
} while (++i < nfiles); |
279 |
} |
} |
280 |
|
if (ENABLE_FEATURE_CLEAN_UP) { |
281 |
return status; |
free(fds); |
282 |
|
} |
283 |
|
return G.status; |
284 |
} |
} |