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-rw-r--r--coreutils/tail.c456
1 files changed, 203 insertions, 253 deletions
diff --git a/coreutils/tail.c b/coreutils/tail.c
index 5f0381882..8e6488931 100644
--- a/coreutils/tail.c
+++ b/coreutils/tail.c
@@ -1,65 +1,30 @@
/* vi: set sw=4 ts=4: */
-/* tail -- output the last part of file(s)
- Copyright (C) 89, 90, 91, 95, 1996 Free Software Foundation, Inc.
-
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2, or (at your option)
- any later version.
-
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
-
- You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software
- Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
-
- Original version by Paul Rubin <phr@ocf.berkeley.edu>.
- Extensions by David MacKenzie <djm@gnu.ai.mit.edu>.
- tail -f for multiple files by Ian Lance Taylor <ian@airs.com>.
-
- Rewrote the option parser, removed locales support,
- and generally busyboxed, Erik Andersen <andersen@lineo.com>
-
- Removed superfluous options and associated code ("-c", "-n", "-q").
- Removed "tail -f" support for multiple files.
- Both changes by Friedrich Vedder <fwv@myrtle.lahn.de>.
+/*
+ * Mini tail implementation for busybox
+ *
+ *
+ * Copyright (C) 2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
- Compleate Rewrite to correctly support "-NUM", "+NUM", and "-s" by
- E.Allen Soard (esp@espsw.net).
+#include "busybox.h"
- */
#include <sys/types.h>
#include <fcntl.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <string.h>
-#include <getopt.h>
-#include "busybox.h"
-
-#define STDIN "standard input"
-#define LINES 0
-#define BYTES 1
-
-static int n_files = 0;
-static char **files = NULL;
-static char * buffer;
-static ssize_t bytes_read=0;
-static ssize_t bs;
-static ssize_t filelocation=0;
-static char pip;
-
-#ifdef BB_FEATURE_SIMPLE_TAIL
-static const char unit_type=LINES;
-#else
-static char unit_type=LINES;
-static char verbose = 0;
-#endif
-
-static off_t units=0;
static struct suffix_mult tail_suffixes[] = {
{ "b", 512 },
@@ -68,232 +33,217 @@ static struct suffix_mult tail_suffixes[] = {
{ NULL, 0 }
};
-static int tail_stream(int fd)
-{
- ssize_t startpoint;
- ssize_t endpoint=0;
- ssize_t count=0;
- ssize_t filesize=0;
- int direction=1;
-
- filelocation=0;
- startpoint=bs=BUFSIZ;
-
- filesize=lseek(fd, -1, SEEK_END)+1;
- pip=(filesize<=0);
-
- if(units>=0)
- lseek(fd,0,SEEK_SET);
- else {
- direction=-1;
- count=1;
- }
- while(units != 0) {
- if (pip) {
- char * line;
- ssize_t f_size=0;
-
- bs=BUFSIZ;
- line=xmalloc(bs);
- while(1) {
- bytes_read=read(fd,line,bs);
- if(bytes_read<=0)
- break;
- buffer=xrealloc(buffer,f_size+bytes_read);
- memcpy(&buffer[f_size],line,bytes_read);
- filelocation=f_size+=bytes_read;
- }
- bs=f_size;
- if(direction<0)
- bs--;
- if (line)
- free(line);
- } else {
- filelocation = lseek(fd, 0, SEEK_CUR);
- if(direction<0) {
- if(filelocation<bs)
- bs=filelocation;
- filelocation = lseek(fd, -bs, SEEK_CUR);
- }
- bytes_read = read(fd, buffer, bs);
- if (bytes_read <= 0)
- break;
- bs=bytes_read;
- }
- startpoint=bs;
- if(direction>0) {
- endpoint=startpoint;
- startpoint=0;
- }
- for(;startpoint!=endpoint;startpoint+=direction) {
#ifndef BB_FEATURE_SIMPLE_TAIL
- if(unit_type==BYTES)
- count++;
- else
+static struct suffix_mult null_suffixes[] = {
+ { NULL, 0 }
+};
#endif
- if(buffer[startpoint-1]=='\n')
- count++;
- if (!pip)
- filelocation=lseek(fd,0,SEEK_CUR);
- if(count==units*direction)
- break;
- }
- if((count==units*direction) | pip)
- break;
- if(direction<0){
- filelocation = lseek(fd, -bytes_read, SEEK_CUR);
- if(filelocation==0)
- break;
- }
- }
- if(pip && (direction<0))
- bs++;
- bytes_read=bs-startpoint;
- memcpy(&buffer[0],&buffer[startpoint],bytes_read);
- return 0;
+#define BYTES 0
+#define LINES 1
+
+static char *tailbuf;
+static int taillen;
+static int newline;
+
+void tailbuf_append(char *buf, int len)
+{
+ tailbuf = xrealloc(tailbuf, taillen + len);
+ memcpy(tailbuf + taillen, buf, len);
+ taillen += len;
}
-void add_file(char *name)
+void tailbuf_trunc()
{
- ++n_files;
- files = xrealloc(files, n_files);
- files[n_files - 1] = (char *) xmalloc(strlen(name) + 1);
- strcpy(files[n_files - 1], name);
+ char *s;
+ s = memchr(tailbuf, '\n', taillen);
+ memmove(tailbuf, s + 1, taillen - ((s + 1) - tailbuf));
+ taillen -= (s + 1) - tailbuf;
+ newline = 0;
}
int tail_main(int argc, char **argv)
{
- int show_headers = 1;
- int test;
- int opt;
- char follow=0;
- int sleep_int=1;
- int *fd;
-
- opterr = 0;
-
- while ((opt=getopt(argc,argv,"c:fhn:s:q:v")) >0) {
+ int from_top = 0, units = LINES, count = 10, sleep_period = 1;
+ int show_headers = 0, hide_headers = 0, follow = 0;
+ int *fds, nfiles = 0, status = EXIT_SUCCESS, nread, nwrite, seen = 0;
+ char *s, *start, *end, buf[BUFSIZ];
+ int i, opt;
+ while ((opt = getopt(argc, argv, "c:fhn:q:s:v")) > 0) {
switch (opt) {
+ case 'f':
+ follow = 1;
+ break;
#ifndef BB_FEATURE_SIMPLE_TAIL
- case 'q':
- show_headers = 0;
- break;
- case 's':
- sleep_int = atoi(optarg);
- if(sleep_int<1)
- sleep_int=1;
- break;
- case 'v':
- verbose = 1;
- break;
- case 'c':
- unit_type = BYTES;
- /* FALLS THROUGH */
+ case 'c':
+ units = BYTES;
+ /* FALLS THROUGH */
#endif
- case 'n':
- test = parse_number(optarg, tail_suffixes);
- if (test) {
+ case 'n':
+ count = parse_number(optarg, tail_suffixes);
+ if (count < 0)
+ count = -count;
if (optarg[0] == '+')
- units = test;
- else
- units = -(test+1);
- } else
+ from_top = 1;
+ break;
+#ifndef BB_FEATURE_SIMPLE_TAIL
+ case 'q':
+ hide_headers = 1;
+ break;
+ case 's':
+ sleep_period = parse_number(optarg, null_suffixes);
+ break;
+ case 'v':
+ show_headers = 1;
+ break;
+#endif
+ default:
usage(tail_usage);
- break;
- case 'f':
- follow = 1;
- break;
- default:
- usage(tail_usage);
}
}
- while (optind <= argc) {
- if(optind==argc) {
- if (n_files==0)
- add_file(STDIN);
- else
- break;
- }else {
- if (!strcmp(argv[optind], "-")) {
- add_file(STDIN);
- } else {
- add_file(argv[optind]);
+
+ /* open all the files */
+ fds = (int *)xmalloc(sizeof(int) * (argc - optind + 1));
+ if (argc == optind) {
+ fds[nfiles++] = STDIN_FILENO;
+ argv[optind] = "standard input";
+ } else {
+ for (i = optind; i < argc; i++) {
+ if (strcmp(argv[i], "-") == 0) {
+ fds[nfiles++] = STDIN_FILENO;
+ argv[i] = "standard input";
+ } else if ((fds[nfiles++] = open(argv[i], O_RDONLY)) < 0) {
+ perror_msg("%s", argv[i]);
+ status = EXIT_FAILURE;
}
- optind++;
}
}
- if(units==0)
- units=-11;
- if(units>0)
- units--;
- fd=xmalloc(sizeof(int)*n_files);
- if (n_files == 1)
+
#ifndef BB_FEATURE_SIMPLE_TAIL
- if (!verbose)
+ /* tail the files */
+ if (!from_top && units == BYTES)
+ tailbuf = xmalloc(count);
#endif
- show_headers = 0;
- buffer=xmalloc(BUFSIZ);
- for (test = 0; test < n_files; test++) {
- if (show_headers)
- printf("==> %s <==\n", files[test]);
- if (!strcmp(files[test], STDIN))
- fd[test] = 0;
- else
- fd[test] = open(files[test], O_RDONLY);
- if (fd[test] == -1)
- error_msg_and_die("Unable to open file %s.\n", files[test]);
- tail_stream(fd[test]);
- bs=BUFSIZ;
- while (1) {
- if((filelocation>0 || pip)){
- write(1,buffer,bytes_read);
+ for (i = 0; i < nfiles; i++) {
+ if (fds[i] == -1)
+ continue;
+ seen = 0;
+ if (show_headers || (!hide_headers && nfiles > 1))
+ printf("%s==> %s <==\n", i == 0 ? "" : "\n", argv[optind + i]);
+ while ((nread = safe_read(fds[i], buf, sizeof(buf))) > 0) {
+ if (from_top) {
+#ifndef BB_FEATURE_SIMPLE_TAIL
+ if (units == BYTES) {
+ if (count - 1 <= seen)
+ nwrite = nread;
+ else if (count - 1 <= seen + nread)
+ nwrite = nread + seen - (count - 1);
+ else
+ nwrite = 0;
+ seen += nread;
+ } else {
+#else
+ {
+#endif
+ if (count - 1 <= seen)
+ nwrite = nread;
+ else {
+ nwrite = 0;
+ for (s = memchr(buf, '\n', nread); s != NULL;
+ s = memchr(s+1, '\n', nread - (s + 1 - buf))) {
+ if (count - 1 <= ++seen) {
+ nwrite = nread - (s + 1 - buf);
+ break;
+ }
+ }
+ }
+ }
+ if (full_write(STDOUT_FILENO, buf + nread - nwrite,
+ nwrite) < 0) {
+ perror_msg("write");
+ status = EXIT_FAILURE;
+ break;
+ }
+ } else {
+#ifndef BB_FEATURE_SIMPLE_TAIL
+ if (units == BYTES) {
+ if (nread < count) {
+ memmove(tailbuf, tailbuf + nread, count - nread);
+ memcpy(tailbuf + count - nread, buf, nread);
+ } else {
+ memcpy(tailbuf, buf + nread - count, count);
+ }
+ seen += nread;
+ } else {
+#else
+ {
+#endif
+ for (start = buf, end = memchr(buf, '\n', nread);
+ end != NULL; start = end+1,
+ end = memchr(start, '\n', nread - (start - buf))) {
+ if (newline && count <= seen)
+ tailbuf_trunc();
+ tailbuf_append(start, end - start + 1);
+ seen++;
+ newline = 1;
+ }
+ if (newline && count <= seen && nread - (start - buf) > 0)
+ tailbuf_trunc();
+ tailbuf_append(start, nread - (start - buf));
+ }
}
- bytes_read = read(fd[test], buffer, bs);
- filelocation+=bytes_read;
- if (bytes_read <= 0) {
- break;
+ }
+
+ if (nread < 0) {
+ perror_msg("read");
+ status = EXIT_FAILURE;
+ }
+
+#ifndef BB_FEATURE_SIMPLE_TAIL
+ if (!from_top && units == BYTES) {
+ if (count < seen)
+ seen = count;
+ if (full_write(STDOUT_FILENO, tailbuf + count - seen, seen) < 0) {
+ perror_msg("write");
+ status = EXIT_FAILURE;
}
- usleep(sleep_int * 1000);
}
- if(n_files>1)
- printf("\n");
+#endif
+
+ if (!from_top && units == LINES) {
+ if (full_write(STDOUT_FILENO, tailbuf, taillen) < 0) {
+ perror_msg("write");
+ status = EXIT_FAILURE;
+ }
+ }
+
+ taillen = 0;
}
- while(1){
- for (test = 0; test < n_files; test++) {
- if(!follow){
- close(fd[test]);
+
+ while (follow) {
+ sleep(sleep_period);
+
+ for (i = 0; i < nfiles; i++) {
+ if (fds[i] == -1)
continue;
- } else {
- sleep(sleep_int);
- bytes_read = read(fd[test], buffer, bs);
- if(bytes_read>0) {
- if (show_headers)
- printf("==> %s <==\n", files[test]);
- write(1,buffer,bytes_read);
- if(n_files>1)
- printf("\n");
- }
+
+ if ((nread = safe_read(fds[i], buf, sizeof(buf))) > 0) {
+ if (show_headers || (!hide_headers && nfiles > 1))
+ printf("\n==> %s <==\n", argv[optind + i]);
+
+ do {
+ full_write(STDOUT_FILENO, buf, nread);
+ } while ((nread = safe_read(fds[i], buf, sizeof(buf))) > 0);
+ }
+
+ if (nread < 0) {
+ perror_msg("read");
+ status = EXIT_FAILURE;
}
}
- if(!follow)
- break;
}
- if (fd)
- free(fd);
- if (buffer)
- free(buffer);
- if(files)
- free(files);
- return 0;
-}
-/*
-Local Variables:
-c-file-style: "linux"
-c-basic-offset: 4
-tab-width: 4
-End:
-*/
+ return status;
+}
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