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tail: implement -F

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function                                             old     new   delta
tail_main                                           1190    1494    +304

Signed-off-by: Eric Lammerts <busybox@lists.lammerts.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Eric Lammerts 2009-07-22 00:31:27 +02:00 committed by Denys Vlasenko
parent 997538ab58
commit 3b5a664440
2 changed files with 66 additions and 21 deletions
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2
coreutils/Config.in
View File

@ -635,7 +635,7 @@ config TAIL
from files.
config FEATURE_FANCY_TAIL
bool "Enable extra tail options (-q, -s, and -v)"
bool "Enable extra tail options (-q, -s, -v, and -F)"
default y
depends on TAIL
help

85
coreutils/tail.c
View File

@ -85,18 +85,15 @@ int tail_main(int argc, char **argv)
unsigned count = 10;
unsigned sleep_period = 1;
bool from_top;
int header_threshhold = 1;
const char *str_c, *str_n;
char *tailbuf;
size_t tailbufsize;
int taillen = 0;
int newlines_seen = 0;
int nfiles, nread, nwrite, i, opt;
unsigned seen;
unsigned header_threshhold = 1;
unsigned nfiles;
int i, opt;
int *fds;
char *s, *buf;
const char *fmt;
#if ENABLE_INCLUDE_SUSv2 || ENABLE_FEATURE_FANCY_TAIL
@ -110,8 +107,9 @@ int tail_main(int argc, char **argv)
}
#endif
IF_FEATURE_FANCY_TAIL(opt_complementary = "s+";) /* -s N */
opt = getopt32(argv, "fc:n:" IF_FEATURE_FANCY_TAIL("qs:v"),
/* -s NUM, -F imlies -f */
IF_FEATURE_FANCY_TAIL(opt_complementary = "s+:Ff";)
opt = getopt32(argv, "fc:n:" IF_FEATURE_FANCY_TAIL("qs:vF"),
&str_c, &str_n IF_FEATURE_FANCY_TAIL(,&sleep_period));
#define FOLLOW (opt & 0x1)
#define COUNT_BYTES (opt & 0x2)
@ -119,8 +117,12 @@ int tail_main(int argc, char **argv)
if (opt & 0x2) count = eat_num(str_c); // -c
if (opt & 0x4) count = eat_num(str_n); // -n
#if ENABLE_FEATURE_FANCY_TAIL
if (opt & 0x8) header_threshhold = INT_MAX; // -q
/* q: make it impossible for nfiles to be > header_threshhold */
if (opt & 0x8) header_threshhold = UINT_MAX; // -q
if (opt & 0x20) header_threshhold = 0; // -v
#define FOLLOW_RETRY (opt & 0x40)
#else
#define FOLLOW_RETRY 0
#endif
argc -= optind;
argv += optind;
@ -128,19 +130,21 @@ int tail_main(int argc, char **argv)
G.status = EXIT_SUCCESS;
/* open all the files */
fds = xmalloc(sizeof(int) * (argc + 1));
fds = xmalloc(sizeof(fds[0]) * (argc + 1));
if (!argv[0]) {
struct stat statbuf;
if (!fstat(STDIN_FILENO, &statbuf) && S_ISFIFO(statbuf.st_mode)) {
if (fstat(STDIN_FILENO, &statbuf) == 0
&& S_ISFIFO(statbuf.st_mode)
) {
opt &= ~1; /* clear FOLLOW */
}
*argv = (char *) bb_msg_standard_input;
argv[0] = (char *) bb_msg_standard_input;
}
nfiles = i = 0;
do {
int fd = open_or_warn_stdin(argv[i]);
if (fd < 0) {
if (fd < 0 && !FOLLOW_RETRY) {
G.status = EXIT_FAILURE;
continue;
}
@ -161,9 +165,18 @@ int tail_main(int argc, char **argv)
tailbuf = xmalloc(tailbufsize);
/* tail the files */
fmt = header_fmt + 1; /* Skip header leading newline on first output. */
fmt = header_fmt + 1; /* skip header leading newline on first output */
i = 0;
do {
char *buf;
int taillen;
int newlines_seen;
unsigned seen;
int nread;
if (ENABLE_FEATURE_FANCY_TAIL && fds[i] < 0)
continue; /* may happen with -E */
if (nfiles > header_threshhold) {
tail_xprint_header(fmt, argv[i]);
fmt = header_fmt;
@ -192,13 +205,13 @@ int tail_main(int argc, char **argv)
newlines_seen = 0;
while ((nread = tail_read(fds[i], buf, tailbufsize-taillen)) > 0) {
if (from_top) {
nwrite = nread;
int nwrite = nread;
if (seen < count) {
if (COUNT_BYTES) {
nwrite -= (count - seen);
seen = count;
} else {
s = buf;
char *s = buf;
do {
--nwrite;
if (*s++ == '\n' && ++seen == count) {
@ -231,6 +244,7 @@ int tail_main(int argc, char **argv)
taillen += nread;
} else {
int extra = (buf[nread-1] != '\n');
char *s;
k = newlines_seen + newlines_in_buf + extra - count;
s = tailbuf;
@ -257,23 +271,54 @@ int tail_main(int argc, char **argv)
}
} while (++i < nfiles);
buf = xrealloc(tailbuf, BUFSIZ);
tailbuf = xrealloc(tailbuf, BUFSIZ);
fmt = NULL;
if (FOLLOW) while (1) {
sleep(sleep_period);
i = 0;
do {
int nread;
const char *filename = argv[i];
int fd = fds[i];
if (FOLLOW_RETRY) {
struct stat sbuf, fsbuf;
if (fd < 0
|| fstat(fd, &fsbuf) < 0
|| stat(filename, &sbuf) < 0
|| fsbuf.st_dev != sbuf.st_dev
|| fsbuf.st_ino != sbuf.st_ino
) {
int new_fd;
if (fd >= 0)
close(fd);
new_fd = open(filename, O_RDONLY);
if (new_fd >= 0) {
bb_error_msg("%s has %s; following end of new file",
filename, (fd < 0) ? "appeared" : "been replaced"
);
} else if (fd >= 0) {
bb_perror_msg("%s has become inaccessible", filename);
}
fds[i] = fd = new_fd;
}
}
if (ENABLE_FEATURE_FANCY_TAIL && fd < 0)
continue;
if (nfiles > header_threshhold) {
fmt = header_fmt;
}
while ((nread = tail_read(fds[i], buf, BUFSIZ)) > 0) {
while ((nread = tail_read(fd, tailbuf, BUFSIZ)) > 0) {
if (fmt) {
tail_xprint_header(fmt, argv[i]);
tail_xprint_header(fmt, filename);
fmt = NULL;
}
xwrite(STDOUT_FILENO, buf, nread);
xwrite(STDOUT_FILENO, tailbuf, nread);
}
} while (++i < nfiles);
}