diff options
| -rw-r--r-- | usr.bin/tail/forward.c | 55 |
1 files changed, 51 insertions, 4 deletions
diff --git a/usr.bin/tail/forward.c b/usr.bin/tail/forward.c index 714efa7de5f..994fcd07baf 100644 --- a/usr.bin/tail/forward.c +++ b/usr.bin/tail/forward.c @@ -1,4 +1,4 @@ -/* $OpenBSD: forward.c,v 1.11 2000/11/21 22:01:47 art Exp $ */ +/* $OpenBSD: forward.c,v 1.12 2001/08/18 14:49:15 art Exp $ */ /* $NetBSD: forward.c,v 1.7 1996/02/13 16:49:10 ghudson Exp $ */ /*- @@ -41,12 +41,13 @@ #if 0 static char sccsid[] = "@(#)forward.c 8.1 (Berkeley) 6/6/93"; #endif -static char rcsid[] = "$OpenBSD: forward.c,v 1.11 2000/11/21 22:01:47 art Exp $"; +static char rcsid[] = "$OpenBSD: forward.c,v 1.12 2001/08/18 14:49:15 art Exp $"; #endif /* not lint */ #include <sys/types.h> #include <sys/stat.h> #include <sys/mman.h> +#include <sys/event.h> #include <err.h> #include <errno.h> @@ -90,8 +91,10 @@ forward(fp, style, off, sbp) long off; struct stat *sbp; { - register int ch; + int ch; struct stat nsb; + int kq; + struct kevent ke; switch(style) { case FBYTES: @@ -170,19 +173,58 @@ forward(fp, style, off, sbp) break; } + kq = -1; +kq_retry: + if (fflag && ((kq = kqueue()) >= 0)) { + ke.ident = fileno(fp); + ke.flags = EV_ENABLE|EV_ADD|EV_CLEAR; + ke.filter = EVFILT_READ; + ke.fflags = ke.data = 0; + ke.udata = NULL; + if (kevent(kq, &ke, 1, NULL, 0, NULL) < 0) { + close(kq); + kq = -1; + } else if (S_ISREG(sbp->st_mode)) { + ke.ident = fileno(fp); + ke.flags = EV_ENABLE|EV_ADD|EV_CLEAR; + ke.filter = EVFILT_VNODE; + ke.fflags = NOTE_DELETE | NOTE_RENAME; + if (kevent(kq, &ke, 1, NULL, 0, NULL) < 0) { + close(kq); + kq = -1; + } + } + } + for (;;) { while (!feof(fp) && (ch = getc(fp)) != EOF) if (putchar(ch) == EOF) oerr(); if (ferror(fp)) { ierr(); + if (kq != -1) + close(kq); return; } (void)fflush(stdout); if (!fflag) break; - sleep(1); clearerr(fp); + if (kq < 0 || kevent(kq, NULL, 0, &ke, 1, NULL) <= 0) { + sleep(1); + } else if (ke.filter == EVFILT_READ) { + continue; + } else { + /* + * File was renamed or deleted. + * + * Continue to look at it until a new file reappears + * with the same name. + * Fall back to the old algorithm for that. + */ + close(kq); + kq = -1; + } if (is_stdin || stat(fname, &nsb) != 0) continue; @@ -191,15 +233,20 @@ forward(fp, style, off, sbp) warnx("%s has been replaced, reopening.", fname); if ((fp = freopen(fname, "r", fp)) == NULL) { ierr(); + if (kq >= 0) + close(kq); return; } (void)memcpy(sbp, &nsb, sizeof(nsb)); + goto kq_retry; } else if (nsb.st_size < sbp->st_size) { warnx("%s has been truncated, resetting.", fname); rewind(fp); (void)memcpy(sbp, &nsb, sizeof(nsb)); } } + if (kq >= 0) + close(kq); } /* |