misc/137365: let last(1) read from stdin via "-f -"

[Jan Schaumann]

>Number:         137365
>Category:       misc
>Synopsis:       let last(1) read from stdin via "-f -"
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          change-request
>Submitter-Id:   current-users
>Arrival-Date:   Sun Aug 02 21:40:03 UTC 2009
>Closed-Date:
>Last-Modified:
>Originator:     Jan Schaumann
>Release:        
>Organization:
>Environment:
>Description:
last -f <file>  lets you read from a specified file.  However, there's no way to read from a pipe.  NetBSD's last(1) let's you use "-f -" to specify reading from stdin -- port this to FreeBSD.
>How-To-Repeat:
cat /var/tmp/wtmp | last -f -
>Fix:
Index: last.c
===================================================================
RCS file: /home/ncvs/src/usr.bin/last/last.c,v
retrieving revision 1.34
diff -b -u -r1.34 last.c
--- last.c      8 Aug 2004 18:59:19 -0000       1.34
+++ last.c      2 Aug 2009 21:24:51 -0000
@@ -216,7 +216,10 @@

        LIST_INIT(&ttylist);

-       if ((wfd = open(file, O_RDONLY, 0)) < 0 || fstat(wfd, &stb) == -1)
+       if (!strcmp(file, "-")) {
+               wfd = STDIN_FILENO;
+               file = "<stdin>";
+       } else if ((wfd = open(file, O_RDONLY, 0)) < 0 || fstat(wfd, &stb) == -1)
                err(1, "%s", file);
        bl = (stb.st_size + sizeof(buf) - 1) / sizeof(buf);

@@ -226,9 +229,11 @@
        (void)signal(SIGQUIT, onintr);

        while (--bl >= 0) {
-               if (lseek(wfd, (off_t)(bl * sizeof(buf)), L_SET) == -1 ||
-                   (bytes = read(wfd, buf, sizeof(buf))) == -1)
+               if (((lseek(wfd, (off_t)(bl * sizeof(buf)), L_SET) == -1) &&
+                       (ESPIPE != errno)) ||
+                               ((bytes = read(wfd, buf, sizeof(buf))) == -1)) {
                        err(1, "%s", file);
+               }
                for (bp = &buf[bytes / sizeof(buf[0]) - 1]; bp >= buf; --bp)
                        doentry(bp);
        }


>Release-Note:
>Audit-Trail:
>Unformatted: