*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
-
-/* BB_AUDIT SUSv3 compliant (need fancy for -c) */
-/* BB_AUDIT GNU compatible -c, -q, and -v options in 'fancy' configuration. */
-/* http://www.opengroup.org/onlinepubs/007904975/utilities/tail.html */
-
/* Mar 16, 2003 Manuel Novoa III (mjn3@codepoet.org)
*
* Pretty much rewritten to fix numerous bugs and reduce realloc() calls.
* 6) no check for lseek error
* 7) lseek attempted when count==0 even if arg was +0 (from top)
*/
+//config:config TAIL
+//config: bool "tail (7.1 kb)"
+//config: default y
+//config: help
+//config: tail is used to print the last specified number of lines
+//config: from files.
+//config:
+//config:config FEATURE_FANCY_TAIL
+//config: bool "Enable -q, -s, -v, and -F options"
+//config: default y
+//config: depends on TAIL
+//config: help
+//config: These options are provided by GNU tail, but
+//config: are not specified in the SUSv3 standard:
+//config: -q Never output headers giving file names
+//config: -s SEC Wait SEC seconds between reads with -f
+//config: -v Always output headers giving file names
+//config: -F Same as -f, but keep retrying
+
+//applet:IF_TAIL(APPLET(tail, BB_DIR_USR_BIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_TAIL) += tail.o
-//kbuild:lib-$(CONFIG_TAIL) += head_tail.o
+
+/* BB_AUDIT SUSv3 compliant (need fancy for -c) */
+/* BB_AUDIT GNU compatible -c, -q, and -v options in 'fancy' configuration. */
+/* http://www.opengroup.org/onlinepubs/007904975/utilities/tail.html */
//usage:#define tail_trivial_usage
//usage: "[OPTIONS] [FILE]..."
//usage: "Print last 10 lines of each FILE (or stdin) to stdout.\n"
//usage: "With more than one FILE, precede each with a filename header.\n"
//usage: "\n -f Print data as file grows"
-//usage: IF_FEATURE_FANCY_TAIL(
-//usage: "\n -s SECONDS Wait SECONDS between reads with -f"
-//usage: )
+//usage: "\n -c [+]N[kbm] Print last N bytes"
//usage: "\n -n N[kbm] Print last N lines"
//usage: "\n -n +N[kbm] Start on Nth line and print the rest"
//usage: IF_FEATURE_FANCY_TAIL(
-//usage: "\n -c [+]N[kbm] Print last N bytes"
//usage: "\n -q Never print headers"
+//usage: "\n -s SECONDS Wait SECONDS between reads with -f"
//usage: "\n -v Always print headers"
+//usage: "\n -F Same as -f, but keep retrying"
//usage: "\n"
//usage: "\nN may be suffixed by k (x1024), b (x512), or m (x1024^2)."
//usage: )
//usage: "nameserver 10.0.0.1\n"
#include "libbb.h"
-#include "head_tail.h"
+#include "common_bufsiz.h"
struct globals {
bool from_top;
bool exitcode;
} FIX_ALIASING;
-#define G (*(struct globals*)&bb_common_bufsiz1)
-#define INIT_G() do { } while (0)
+#define G (*(struct globals*)bb_common_bufsiz1)
+#define INIT_G() do { setup_common_bufsiz(); } while (0)
static void tail_xprint_header(const char *fmt, const char *filename)
{
static ssize_t tail_read(int fd, char *buf, size_t count)
{
ssize_t r;
- off_t current;
- struct stat sbuf;
-
- /* /proc files report zero st_size, don't lseek them. */
- if (fstat(fd, &sbuf) == 0 && sbuf.st_size > 0) {
- current = lseek(fd, 0, SEEK_CUR);
- if (sbuf.st_size < current)
- xlseek(fd, 0, SEEK_SET);
- }
r = full_read(fd, buf, count);
if (r < 0) {
p++;
G.from_top = 1;
}
- return xatou_sfx(p, head_tail_suffixes);
+ return xatou_sfx(p, bkm_suffixes);
}
int tail_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int *fds;
const char *fmt;
+ int prev_fd;
INIT_G();
#endif
/* -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));
+ opt = getopt32(argv, IF_FEATURE_FANCY_TAIL("^")
+ "fc:n:"IF_FEATURE_FANCY_TAIL("qs:+vF")
+ IF_FEATURE_FANCY_TAIL("\0" "Ff"),
+ &str_c, &str_n IF_FEATURE_FANCY_TAIL(,&sleep_period)
+ );
#define FOLLOW (opt & 0x1)
#define COUNT_BYTES (opt & 0x2)
//if (opt & 0x1) // -f
xwrite(STDOUT_FILENO, tailbuf, taillen);
}
} while (++i < nfiles);
+ prev_fd = fds[i-1];
tailbuf = xrealloc(tailbuf, BUFSIZ);
if (nfiles > header_threshhold) {
fmt = header_fmt_str;
}
- while ((nread = tail_read(fd, tailbuf, BUFSIZ)) > 0) {
- if (fmt) {
+ for (;;) {
+ /* tail -f keeps following files even if they are truncated */
+ struct stat sbuf;
+ /* /proc files report zero st_size, don't lseek them */
+ if (fstat(fd, &sbuf) == 0 && sbuf.st_size > 0) {
+ off_t current = lseek(fd, 0, SEEK_CUR);
+ if (sbuf.st_size < current)
+ xlseek(fd, 0, SEEK_SET);
+ }
+
+ nread = tail_read(fd, tailbuf, BUFSIZ);
+ if (nread <= 0)
+ break;
+ if (fmt && (fd != prev_fd)) {
tail_xprint_header(fmt, filename);
fmt = NULL;
+ prev_fd = fd;
}
xwrite(STDOUT_FILENO, tailbuf, nread);
}
projects / oweals / busybox.git / blobdiff