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Add a new -F flag which is a superset of -f. It will cause tail to

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stat() the file being followed and do a close/reopen if the file has been
renamed and/or rotated.  This is damn useful for leaving running on files
in /var/log when newsyslog(8) rotates them.
This commit is contained in:
Peter Wemm 1998-04-06 16:13:49 +00:00
parent aacdc613e5
commit eb1c943900
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=35081
4 changed files with 42 additions and 4 deletions
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2
usr.bin/tail/extern.h
View File

@ -48,5 +48,5 @@ int lines __P((FILE *, off_t));
void ierr __P((void));
void oerr __P((void));
extern int fflag, rflag, rval;
extern int Fflag, fflag, rflag, rval;
extern char *fname;

16
usr.bin/tail/forward.c
View File

@ -86,6 +86,7 @@ forward(fp, style, off, sbp)
{
register int ch;
struct timeval interval;
struct stat sb2;
switch(style) {
case FBYTES:
@ -179,6 +180,21 @@ forward(fp, style, off, sbp)
(void) usleep(250000);
clearerr(fp);
if (Fflag && fileno(fp) != STDIN_FILENO &&
stat(fname, &sb2) != -1) {
if (sb2.st_ino != sbp->st_ino ||
sb2.st_dev != sbp->st_dev ||
sb2.st_rdev != sbp->st_rdev ||
sb2.st_nlink == 0) {
fp = freopen(fname, "r", fp);
if (fp == NULL) {
ierr();
break;
}
*sbp = sb2;
}
}
}
}

21
usr.bin/tail/tail.1
View File

@ -42,7 +42,11 @@
.Nd display the last part of a file
.Sh SYNOPSIS
.Nm
.Op Fl f Li | Fl r
.Oo
.Fl F |
.Fl f |
.Fl r
.Oc
.Oo
.Fl b Ar number |
.Fl c Ar number |
@ -91,6 +95,20 @@ data to be appended to the input.
The
.Fl f
option is ignored if the standard input is a pipe, but not if it is a FIFO.
.It Fl F
The
.Fl F
option implies the
.Fl f
option, but
.Nm
will also check to see if the file being followed has been renamed or rotated.
The file is closed and reopened when
.Nm
detects that the filename being read from has a new inode number.
The
.Fl F
option is ignored if reading from standard input rather than a file.
.It Fl n Ar number
The location is
.Ar number
@ -136,6 +154,7 @@ utility is expected to be a superset of the
.St -p1003.2-92
specification.
In particular, the
.Fl F ,
.Fl b
and
.Fl r

7
usr.bin/tail/tail.c
View File

@ -54,7 +54,7 @@ static char sccsid[] = "@(#)tail.c 8.1 (Berkeley) 6/6/93";
#include <err.h>
#include "extern.h"
int fflag, rflag, rval;
int Fflag, fflag, rflag, rval;
char *fname;
static void obsolete __P((char **));
@ -107,8 +107,11 @@ main(argc, argv)
obsolete(argv);
style = NOTSET;
while ((ch = getopt(argc, argv, "b:c:fn:r")) != -1)
while ((ch = getopt(argc, argv, "Fb:c:fn:r")) != -1)
switch(ch) {
case 'F': /* -F is superset of (and implies) -f */
Fflag = fflag = 1;
break;
case 'b':
ARG(512, FBYTES, RBYTES);
break;