libkmod: Fix open file which some char device

use lseek SEEK_CUR to get whether it is a regular file,
lseek return -ESPIPE when fd is associated with a pipe, socket, or FIFO.

commit 883d931d1bd04b089b85b554d1df6f41dcf5fbf5 upstream
("modprobe: Allow passing path to module") allow to modprobe a file,
but not handle opening a FIFO device such as modprobe /dev/tty1.

commit 8d03b6c7d990af301950d3ecdc4b5c69fa525928 uptream
("libkmod: Use pread where appropriate") fix some cases,
such as open /dev/tty1, but not for /dev/vmnet0 or /dev/userio etc.

Can be reproduced in run lshw in root and install some vm such ad vmware,
more about the case are in the Link.

Reference: https://github.com/lyonel/lshw/pull/110
Closes: https://bugs.launchpad.net/ubuntu/+source/lshw/+bug/2069649
Closes: https://bbs.deepin.org.cn/post/291466
Reported-by: Qi Xu <xuqi@uniontech.com>
Reported-by: lionheartyu <dongshengyuan@uniontech.com>
Fixes: 883d931d1bd04 ("modprobe: Allow passing path to module")
Signed-off-by: Wentao Guan <guanwentao@uniontech.com>
Reviewed-by: Lucas De Marchi <demarchi@kernel.org>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Link: https://github.com/kmod-project/kmod/pull/407
Signed-off-by: Lucas De Marchi <demarchi@kernel.org>

diff --git a/libkmod/libkmod-file.c b/libkmod/libkmod-file.c
index d651fa2e4eb5ee49a5b6cd6416225817570d786c..706fef4dc0357c7e2ec386b3f0bbf0af3dbf3566 100644 (file)
--- a/libkmod/libkmod-file.c
+++ b/libkmod/libkmod-file.c
@@ -96,6 +96,13 @@ int kmod_file_open(const struct kmod_ctx *ctx, const char *filename,
        if (file->fd < 0)
                return -errno;
 
        if (file->fd < 0)
                return -errno;
 

+       /*
+        * Bail out if underlying fd is not seekable  - that is not supported
+        */
+       ret = lseek(file->fd, 0, SEEK_CUR);
+       if (ret < 0)
+               return ret;
+

        sz = pread_str_safe(file->fd, buf, sizeof(buf), 0);
        if (sz != (sizeof(buf) - 1)) {
                if (sz < 0)
        sz = pread_str_safe(file->fd, buf, sizeof(buf), 0);
        if (sz != (sizeof(buf) - 1)) {
                if (sz < 0)