tail: work correctly on /proc files (Kazuo TAKADA <kztakada@sm.sony.co.jp>)

This commit is contained in:
Denis Vlasenko 2007-10-02 10:17:56 +00:00
parent ebeaea04dc
commit 368a12efc2

View File

@ -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);
}