[libvirt] [PATCH] virFileInData: Report an error if unable to reposition file

The purpose of this function is to tell if the current position in given FD is in data section or a hole and how much bytes there is remaining until the end of the section. This is achieved by couple of lseeks(). The most important part is that we reposition the FD back, so that the position is unchanged from the caller POV. And until now the final lseek() back to the original position was done with no check for errors. And I was convinced that that's okay since nothing can go wrong. However, John persuaded me, that it's better to be safe than sorry. Therefore, lets check if the final lseek() succeeded and if it doesn't report an error. Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; --- src/util/virfile.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/src/util/virfile.c b/src/util/virfile.c index d444b32f8..2f28e83f4 100644 --- a/src/util/virfile.c +++ b/src/util/virfile.c @@ -3900,8 +3900,12 @@ virFileInData(int fd, ret = 0; cleanup: /* At any rate, reposition back to where we started. */ - if (cur != (off_t) -1) - ignore_value(lseek(fd, cur, SEEK_SET)); + if (cur != (off_t) -1 && + lseek(fd, cur, SEEK_SET) == (off_t) -1) { + virReportSystemError(errno, "%s", + _("unable to restore position in file")); + ret = -1; + } return ret; } -- 2.13.0