tail: code shrink

function                                             old     new   delta
tail_main                                           1548    1613     +65
tail_read                                            136      34    -102
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/1 up/down: 65/-102)           Total: -37 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/coreutils/tail.c b/coreutils/tail.c
index fb07ca2..c9f9d00 100644 (file)
--- a/coreutils/tail.c
+++ b/coreutils/tail.c
@@ -66,23 +66,10 @@ static void tail_xprint_header(const char *fmt, const char *filename)
                bb_perror_nomsg_and_die();
 }
 
-static ssize_t tail_read(int fd, char *buf, size_t count, int follow)
+static ssize_t tail_read(int fd, char *buf, size_t count)
 {
        ssize_t r;
 
-       if (follow) {
-               /* tail -f keeps following files even if they are truncated */
-               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) {
                bb_perror_msg(bb_msg_read_error);
@@ -255,7 +242,7 @@ int tail_main(int argc, char **argv)
                 * Used only by +N code ("start from Nth", 1-based): */
                seen = 1;
                newlines_seen = 0;
-               while ((nread = tail_read(fd, buf, tailbufsize - taillen, /*follow:*/ 0)) > 0) {
+               while ((nread = tail_read(fd, buf, tailbufsize - taillen)) > 0) {
                        if (G.from_top) {
                                int nwrite = nread;
                                if (seen < count) {
@@ -367,7 +354,19 @@ int tail_main(int argc, char **argv)
                        if (nfiles > header_threshhold) {
                                fmt = header_fmt_str;
                        }
-                       while ((nread = tail_read(fd, tailbuf, BUFSIZ, /*follow:*/ 1)) > 0) {
+                       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) {
                                        tail_xprint_header(fmt, filename);
                                        fmt = NULL;