uptime: fix a problem with subsequent reads.

When doing subsequent reads of uptime on an open file handle
in the form:

read
lseek 0L, SEEK_SET
read

the second (and later) reads cause that the error
"failed to write to cache" was printed. This
happens for example with "top". top would print the error:

bad data in /proc/uptime

To fix this problem use the whole size of the buffer instead of the d->size
because this is set on the first read.

This behavior was introduced with commit 0ecddf023a4caf8e8d2fe7e9125d777a06c5ec12.

Signed-off-by: Bernhard Miklautz <bernhard.miklautz@shacknet.at>

diff --git a/bindings.c b/bindings.c
index 1442b9a52365dd32ca168b29bbac7dd2a2992ee1..d7c2d1da7fd067b7c6b3c6efcc35b0193d2b906c 100644 (file)
--- a/bindings.c
+++ b/bindings.c
@@ -3842,10 +3842,10 @@ static int proc_uptime_read(char *buf, size_t size, off_t offset,
 #endif
 
        if (offset){
-               if (offset > d->size)
-                       return -EINVAL;
                if (!d->cached)
                        return 0;
+               if (offset > d->size)
+                       return -EINVAL;
                int left = d->size - offset;
                total_len = left > size ? size: left;
                memcpy(buf, cache + offset, total_len);
@@ -3860,8 +3860,8 @@ static int proc_uptime_read(char *buf, size_t size, off_t offset,
        if (reaperage >= busytime)
                idletime = reaperage - busytime;
 
-       total_len = snprintf(d->buf, d->size, "%"PRIu64".00 %"PRIu64".00\n", reaperage, idletime);
-       if (total_len < 0 || total_len >=  d->size){
+       total_len = snprintf(d->buf, d->buflen, "%"PRIu64".00 %"PRIu64".00\n", reaperage, idletime);
+       if (total_len < 0 || total_len >=  d->buflen){
                lxcfs_error("%s\n", "failed to write to cache");
                return 0;
        }