From: Jim Meyering <jim@meyering.net>
Date: Tue, 13 Nov 2001 10:14:12 +0000 (+0000)
Subject: `tail /proc/ksyms' would segfault on Linux.
X-Git-Tag: TEXTUTILS-2_0_17~90
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=5579ee544c18c78176474c1a0266ec25630e0980;p=thirdparty%2Fcoreutils.git

`tail /proc/ksyms' would segfault on Linux.

(tail_lines): Use status of lseek (...SEEK_END) call
in deciding whether to call file_lines or pipe_lines.
From Herbert Xu.
---

diff --git a/src/tail.c b/src/tail.c
index 4973ef64bd..375e6316bd 100644
--- a/src/tail.c
+++ b/src/tail.c
@@ -1095,14 +1095,14 @@ tail_lines (const char *pretty_filename, int fd, long int n_lines)
     {
       /* Use file_lines only if FD refers to a regular file with
          its file pointer positioned at beginning of file.  */
-      /* FIXME: adding the lseek conjunct is a kludge.
+      /* FIXME: this first lseek conjunct is a kludge.
 	 Once there's a reasonable test suite, fix the true culprit:
 	 file_lines.  file_lines shouldn't presume that the input
 	 file pointer is initially positioned to beginning of file.  */
       if (S_ISREG (stats.st_mode)
-	  && lseek (fd, (off_t) 0, SEEK_CUR) == (off_t) 0)
+	  && lseek (fd, (off_t) 0, SEEK_CUR) == (off_t) 0
+	  && (length = lseek (fd, (off_t) 0, SEEK_END)) >= 0)
 	{
-	  length = lseek (fd, (off_t) 0, SEEK_END);
 	  if (length != 0 && file_lines (pretty_filename, fd, n_lines, length))
 	    return 1;
 	}