tail: -50 text bytes
This commit is contained in:
Denis Vlasenko
parent
f4c52b32db
commit
e31f721e14
136
coreutils/tail.c
136
coreutils/tail.c
@ -29,44 +29,30 @@
|
||||
static const struct suffix_mult tail_suffixes[] = {
|
||||
{ "b", 512 },
|
||||
{ "k", 1024 },
|
||||
{ "m", 1048576 },
|
||||
{ "m", 1024*1024 },
|
||||
{ NULL, 0 }
|
||||
};
|
||||
|
||||
static int status;
|
||||
|
||||
static void tail_xbb_full_write(const char *buf, size_t len)
|
||||
{
|
||||
/* If we get a write error, there is really no sense in continuing. */
|
||||
if (full_write(STDOUT_FILENO, buf, len) < 0)
|
||||
bb_perror_nomsg_and_die();
|
||||
}
|
||||
|
||||
static void tail_xprint_header(const char *fmt, const char *filename)
|
||||
{
|
||||
#if defined __GLIBC__
|
||||
if (dprintf(STDOUT_FILENO, fmt, filename) < 0) {
|
||||
if (fdprintf(STDOUT_FILENO, fmt, filename) < 0)
|
||||
bb_perror_nomsg_and_die();
|
||||
}
|
||||
#else
|
||||
int hdr_len = strlen(fmt) + strlen(filename);
|
||||
char *hdr = xzalloc(hdr_len);
|
||||
sprintf(hdr, filename, filename);
|
||||
tail_xbb_full_write(hdr, hdr_len);
|
||||
#endif
|
||||
}
|
||||
|
||||
static ssize_t tail_read(int fd, char *buf, size_t count)
|
||||
{
|
||||
ssize_t r;
|
||||
off_t current,end;
|
||||
off_t current, end;
|
||||
struct stat sbuf;
|
||||
|
||||
end = current = lseek(fd, 0, SEEK_CUR);
|
||||
if (!fstat(fd, &sbuf))
|
||||
end = sbuf.st_size;
|
||||
lseek(fd, end < current ? 0 : current, SEEK_SET);
|
||||
if ((r = safe_read(fd, buf, count)) < 0) {
|
||||
r = safe_read(fd, buf, count);
|
||||
if (r < 0) {
|
||||
bb_perror_msg(bb_msg_read_error);
|
||||
status = EXIT_FAILURE;
|
||||
}
|
||||
@ -74,82 +60,55 @@ static ssize_t tail_read(int fd, char *buf, size_t count)
|
||||
return r;
|
||||
}
|
||||
|
||||
static const char tail_opts[] =
|
||||
"fn:c:"
|
||||
#if ENABLE_FEATURE_FANCY_TAIL
|
||||
"qs:v"
|
||||
#endif
|
||||
;
|
||||
|
||||
static const char header_fmt[] = "\n==> %s <==\n";
|
||||
|
||||
int tail_main(int argc, char **argv)
|
||||
{
|
||||
long count = 10;
|
||||
unsigned count = 10;
|
||||
unsigned sleep_period = 1;
|
||||
int from_top = 0;
|
||||
int follow = 0;
|
||||
int header_threshhold = 1;
|
||||
int count_bytes = 0;
|
||||
const char *str_c, *str_n, *str_s;
|
||||
|
||||
char *tailbuf;
|
||||
size_t tailbufsize;
|
||||
int taillen = 0;
|
||||
int newline = 0;
|
||||
int nfiles, nread, nwrite, seen, i, opt;
|
||||
|
||||
int *fds, nfiles, nread, nwrite, seen, i, opt;
|
||||
int *fds;
|
||||
char *s, *buf;
|
||||
const char *fmt;
|
||||
|
||||
void eat_num(const char *p) {
|
||||
if (*p == '-') p++;
|
||||
else if (*p == '+') { p++; from_top = 1; }
|
||||
count = xatou_sfx(p, tail_suffixes);
|
||||
}
|
||||
|
||||
|
||||
#if ENABLE_INCLUDE_SUSv2 || ENABLE_FEATURE_FANCY_TAIL
|
||||
/* Allow legacy syntax of an initial numeric option without -n. */
|
||||
if (argc >= 2 && (argv[1][0] == '+' || argv[1][0] == '-')
|
||||
&& isdigit(argv[1][1])
|
||||
) {
|
||||
optind = 2;
|
||||
optarg = argv[1];
|
||||
goto GET_COUNT;
|
||||
argv[0] = "-n";
|
||||
argv--;
|
||||
argc++;
|
||||
}
|
||||
#endif
|
||||
|
||||
while ((opt = getopt(argc, argv, tail_opts)) > 0) {
|
||||
switch (opt) {
|
||||
case 'f':
|
||||
follow = 1;
|
||||
break;
|
||||
case 'c':
|
||||
count_bytes = 1;
|
||||
/* FALLS THROUGH */
|
||||
case 'n':
|
||||
#if ENABLE_INCLUDE_SUSv2 || ENABLE_FEATURE_FANCY_TAIL
|
||||
GET_COUNT:
|
||||
#endif
|
||||
from_top = 0;
|
||||
if (*optarg == '+') {
|
||||
++optarg;
|
||||
from_top = 1;
|
||||
}
|
||||
count = xatol_sfx(optarg, tail_suffixes);
|
||||
/* Note: Leading whitespace is an error trapped above. */
|
||||
if (count < 0) {
|
||||
count = -count;
|
||||
}
|
||||
break;
|
||||
opt = getopt32(argc, argv, "fc:n:" USE_FEATURE_FANCY_TAIL("qs:v"), &str_c, &str_n, &str_s);
|
||||
#define FOLLOW (opt & 0x1)
|
||||
#define COUNT_BYTES (opt & 0x2)
|
||||
//if (opt & 0x1) // -f
|
||||
if (opt & 0x2) eat_num(str_c); // -c
|
||||
if (opt & 0x4) eat_num(str_n); // -n
|
||||
#if ENABLE_FEATURE_FANCY_TAIL
|
||||
case 'q':
|
||||
header_threshhold = INT_MAX;
|
||||
break;
|
||||
case 's':
|
||||
sleep_period = xatou(optarg);
|
||||
break;
|
||||
case 'v':
|
||||
header_threshhold = 0;
|
||||
break;
|
||||
if (opt & 0x8) header_threshhold = INT_MAX; // -q
|
||||
if (opt & 0x10) sleep_period = xatou(str_s); // -s
|
||||
if (opt & 0x20) header_threshhold = 0; // -v
|
||||
#endif
|
||||
default:
|
||||
bb_show_usage();
|
||||
}
|
||||
}
|
||||
argc -= optind;
|
||||
argv += optind;
|
||||
|
||||
@ -160,34 +119,35 @@ int tail_main(int argc, char **argv)
|
||||
struct stat statbuf;
|
||||
|
||||
if (!fstat(STDIN_FILENO, &statbuf) && S_ISFIFO(statbuf.st_mode)) {
|
||||
follow = 0;
|
||||
opt &= ~1; /* clear FOLLOW */
|
||||
}
|
||||
*argv = (char *) bb_msg_standard_input;
|
||||
goto DO_STDIN;
|
||||
}
|
||||
|
||||
do {
|
||||
if (LONE_DASH(argv[i])) {
|
||||
DO_STDIN:
|
||||
if (NOT_LONE_DASH(argv[i])) {
|
||||
fds[nfiles] = open(argv[i], O_RDONLY);
|
||||
if (fds[nfiles] < 0) {
|
||||
bb_perror_msg("%s", argv[i]);
|
||||
status = EXIT_FAILURE;
|
||||
continue;
|
||||
}
|
||||
} else {
|
||||
DO_STDIN: /* "-" */
|
||||
fds[nfiles] = STDIN_FILENO;
|
||||
} else if ((fds[nfiles] = open(argv[i], O_RDONLY)) < 0) {
|
||||
bb_perror_msg("%s", argv[i]);
|
||||
status = EXIT_FAILURE;
|
||||
continue;
|
||||
}
|
||||
argv[nfiles] = argv[i];
|
||||
++nfiles;
|
||||
} while (++i < argc);
|
||||
|
||||
if (!nfiles) {
|
||||
if (!nfiles)
|
||||
bb_error_msg_and_die("no files");
|
||||
}
|
||||
|
||||
tailbufsize = BUFSIZ;
|
||||
|
||||
/* tail the files */
|
||||
if (from_top < count_bytes) { /* Each is 0 or 1, so true iff 0 < 1. */
|
||||
/* Hence, !from_top && count_bytes */
|
||||
if (!from_top && COUNT_BYTES) {
|
||||
if (tailbufsize < count) {
|
||||
tailbufsize = count + BUFSIZ;
|
||||
}
|
||||
@ -203,7 +163,7 @@ int tail_main(int argc, char **argv)
|
||||
* 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)) {
|
||||
if (!(count|from_top) && lseek(fds[i], 0, SEEK_END) >= 0) {
|
||||
continue;
|
||||
}
|
||||
|
||||
@ -221,22 +181,22 @@ int tail_main(int argc, char **argv)
|
||||
if (from_top) {
|
||||
nwrite = nread;
|
||||
if (seen < count) {
|
||||
if (count_bytes) {
|
||||
if (COUNT_BYTES) {
|
||||
nwrite -= (count - seen);
|
||||
seen = count;
|
||||
} else {
|
||||
s = buf;
|
||||
do {
|
||||
--nwrite;
|
||||
if ((*s++ == '\n') && (++seen == count)) {
|
||||
if (*s++ == '\n' && ++seen == count) {
|
||||
break;
|
||||
}
|
||||
} while (nwrite);
|
||||
}
|
||||
}
|
||||
tail_xbb_full_write(buf + nread - nwrite, nwrite);
|
||||
xwrite(STDOUT_FILENO, buf + nread - nwrite, nwrite);
|
||||
} else if (count) {
|
||||
if (count_bytes) {
|
||||
if (COUNT_BYTES) {
|
||||
taillen += nread;
|
||||
if (taillen > count) {
|
||||
memmove(tailbuf, tailbuf + taillen - count, count);
|
||||
@ -286,7 +246,7 @@ int tail_main(int argc, char **argv)
|
||||
}
|
||||
|
||||
if (!from_top) {
|
||||
tail_xbb_full_write(tailbuf, taillen);
|
||||
xwrite(STDOUT_FILENO, tailbuf, taillen);
|
||||
}
|
||||
|
||||
taillen = 0;
|
||||
@ -296,7 +256,7 @@ int tail_main(int argc, char **argv)
|
||||
|
||||
fmt = NULL;
|
||||
|
||||
while (follow) {
|
||||
if (FOLLOW) while (1) {
|
||||
sleep(sleep_period);
|
||||
i = 0;
|
||||
do {
|
||||
@ -308,7 +268,7 @@ int tail_main(int argc, char **argv)
|
||||
tail_xprint_header(fmt, argv[i]);
|
||||
fmt = NULL;
|
||||
}
|
||||
tail_xbb_full_write(buf, nread);
|
||||
xwrite(STDOUT_FILENO, buf, nread);
|
||||
}
|
||||
} while (++i < nfiles);
|
||||
}
|
||||
|
||||
Loading…
Reference in New Issue
Block a user