tail: -50 text bytes

This commit is contained in:
Denis Vlasenko 2006-12-22 16:06:16 +00:00
parent f4c52b32db
commit e31f721e14

View File

@ -29,32 +29,17 @@
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)
{
@ -66,7 +51,8 @@ static ssize_t tail_read(int fd, char *buf, size_t count)
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:
fds[nfiles] = STDIN_FILENO;
} else if ((fds[nfiles] = open(argv[i], O_RDONLY)) < 0) {
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;
}
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);
}