From 368a12efc24d9e9c758ee99239f79e5f443e6c0e Mon Sep 17 00:00:00 2001
From: Denis Vlasenko <vda.linux@googlemail.com>
Date: Tue, 2 Oct 2007 10:17:56 +0000
Subject: tail: work correctly on /proc files (Kazuo TAKADA
<kztakada@sm.sony.co.jp>)
---
coreutils/tail.c | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)
diff --git a/coreutils/tail.c b/coreutils/tail.c
index 74e14232d..8a112346d 100644
--- a/coreutils/tail.c
+++ b/coreutils/tail.c
@@ -47,13 +47,16 @@ static void tail_xprint_header(const char *fmt, const char *filename)
static ssize_t tail_read(int fd, char *buf, size_t count)
{
ssize_t r;
- off_t current, end;
+ off_t current;
struct stat sbuf;
- end = current = lseek(fd, 0, SEEK_CUR);
- if (!fstat(fd, &sbuf))
- end = sbuf.st_size;
- lseek(fd, end < current ? 0 : current, SEEK_SET);
+ /* (A good comment is missing here) */
+ current = lseek(fd, 0, SEEK_CUR);
+ /* /proc files report zero st_size, don't lseek them. */
+ if (fstat(fd, &sbuf) == 0 && sbuf.st_size)
+ if (sbuf.st_size < current)
+ lseek(fd, 0, SEEK_SET);
+
r = safe_read(fd, buf, count);
if (r < 0) {
bb_perror_msg(bb_msg_read_error);
@@ -67,8 +70,12 @@ static const char header_fmt[] ALIGN1 = "\n==> %s <==\n";
static unsigned eat_num(const char *p)
{
- if (*p == '-') p++;
- else if (*p == '+') { p++; G.status = EXIT_FAILURE; }
+ if (*p == '-')
+ p++;
+ else if (*p == '+') {
+ p++;
+ G.status = EXIT_FAILURE;
+ }
return xatou_sfx(p, tail_suffixes);
}
--
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