use bb_xbind/bb_xlisten

[oweals/busybox.git] / coreutils / tail.c

diff --git a/coreutils/tail.c b/coreutils/tail.c
index 8e0adf5b5c5e927ee71a8c40450bee962be875f8..e63406e3155631d1045cd43889718b28202fa6e5 100644 (file)
--- a/coreutils/tail.c
+++ b/coreutils/tail.c
@@ -4,20 +4,7 @@
  *
  * 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
- *
+ * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  */
 
 /* BB_AUDIT SUSv3 compliant (need fancy for -c) */
@@ -53,11 +40,7 @@ static const struct suffix_mult tail_suffixes[] = {
        { NULL, 0 }
 };
 
-static int status
-#if EXIT_SUCCESS != 0
-       = EXIT_SUCCESS  /* If it is 0 (paranoid check), let bss initialize it. */
-#endif
-       ;
+static int status;
 
 static void tail_xprint_header(const char *fmt, const char *filename)
 {
@@ -79,9 +62,15 @@ static void tail_xbb_full_write(const char *buf, size_t len)
 static ssize_t tail_read(int fd, char *buf, size_t count)
 {
        ssize_t r;
+       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) {
-               bb_perror_msg("read");
+               bb_perror_msg(bb_msg_read_error);
                status = EXIT_FAILURE;
        }
 
@@ -89,9 +78,9 @@ static ssize_t tail_read(int fd, char *buf, size_t count)
 }
 
 static const char tail_opts[] =
-       "fn:"
-#ifdef CONFIG_FEATURE_FANCY_TAIL
-       "c:qs:v"
+       "fn:c:"
+#if ENABLE_FEATURE_FANCY_TAIL
+       "qs:v"
 #endif
        ;
 
@@ -104,9 +93,7 @@ int tail_main(int argc, char **argv)
        int from_top = 0;
        int follow = 0;
        int header_threshhold = 1;
-#ifdef CONFIG_FEATURE_FANCY_TAIL
        int count_bytes = 0;
-#endif
 
        char *tailbuf;
        size_t tailbufsize;
@@ -117,29 +104,30 @@ int tail_main(int argc, char **argv)
        char *s, *buf;
        const char *fmt;
 
+#if !ENABLE_DEBUG_YANK_SUSv2 || ENABLE_FEATURE_FANCY_TAIL
        /* Allow legacy syntax of an initial numeric option without -n. */
-       if ((argv[1][0] == '+')
-               || ((argv[1][0] == '-')
+       if (argc >=2 && ((argv[1][0] == '+') || ((argv[1][0] == '-')
                        /* && (isdigit)(argv[1][1]) */
-                       && (((unsigned int)(argv[1][1] - '0')) <= 9))
-               ) {
+                       && (((unsigned int)(argv[1][1] - '0')) <= 9))))
+       {
                optind = 2;
                optarg = argv[1];
                goto GET_COUNT;
        }
+#endif
 
        while ((opt = getopt(argc, argv, tail_opts)) > 0) {
                switch (opt) {
                        case 'f':
                                follow = 1;
                                break;
-#ifdef CONFIG_FEATURE_FANCY_TAIL
                        case 'c':
                                count_bytes = 1;
                                /* FALLS THROUGH */
-#endif
                        case 'n':
+#if !ENABLE_DEBUG_YANK_SUSv2 || ENABLE_FEATURE_FANCY_TAIL
                        GET_COUNT:
+#endif
                                count = bb_xgetlarg10_sfx(optarg, tail_suffixes);
                                /* Note: Leading whitespace is an error trapped above. */
                                if (*optarg == '+') {
@@ -151,7 +139,7 @@ int tail_main(int argc, char **argv)
                                        count = -count;
                                }
                                break;
-#ifdef CONFIG_FEATURE_FANCY_TAIL
+#if ENABLE_FEATURE_FANCY_TAIL
                        case 'q':
                                header_threshhold = INT_MAX;
                                break;
@@ -202,7 +190,7 @@ int tail_main(int argc, char **argv)
        }
 
        tailbufsize = BUFSIZ;
-#ifdef CONFIG_FEATURE_FANCY_TAIL
+
        /* tail the files */
        if (from_top < count_bytes) {   /* Each is 0 or 1, so true iff 0 < 1. */
                /* Hence, !from_top && count_bytes */
@@ -210,7 +198,7 @@ int tail_main(int argc, char **argv)
                        tailbufsize = count + BUFSIZ;
                }
        }
-#endif
+
        buf = tailbuf = xmalloc(tailbufsize);
 
        fmt = header_fmt + 1;   /* Skip header leading newline on first output. */
@@ -233,18 +221,16 @@ int tail_main(int argc, char **argv)
                buf = tailbuf;
                taillen = 0;
                seen = 1;
+               newline = 0;
 
                while ((nread = tail_read(fds[i], buf, tailbufsize-taillen)) > 0) {
                        if (from_top) {
                                nwrite = nread;
                                if (seen < count) {
-#ifdef CONFIG_FEATURE_FANCY_TAIL
                                        if (count_bytes) {
                                                nwrite -= (count - seen);
                                                seen = count;
-                                       } else
-#endif
-                                       {
+                                       } else {
                                                s = buf;
                                                do {
                                                        --nwrite;
@@ -256,16 +242,13 @@ int tail_main(int argc, char **argv)
                                }
                                tail_xbb_full_write(buf + nread - nwrite, nwrite);
                        } else if (count) {
-#ifdef CONFIG_FEATURE_FANCY_TAIL
                                if (count_bytes) {
                                        taillen += nread;
                                        if (taillen > count) {
                                                memmove(tailbuf, tailbuf + taillen - count, count);
                                                taillen = count;
                                        }
-                               } else
-#endif
-                               {
+                               } else {
                                        int k = nread;
                                        int nbuf = 0;