From c3c258c1794231c9dba49b80128c53e018640332 Mon Sep 17 00:00:00 2001 From: Ian Jackson Date: Tue, 14 Oct 2008 11:46:53 +0100 Subject: [PATCH] Fix blktap device backend patch check Regarding http://bugzilla.xensource.com/bugzilla/show_bug.cgi?id=1367, it appears that the expected backend path check is too strict for' blktap devices. Therefore if the devtype is `vbd' we allow the backend to be `tap'. Thanks to report and inspiration from Yosuke Iwamatsu. Signed-off-by: Ian Jackson (cherry picked from commit 629adb3f5244169731ff18b16ae919641d81ad76) --- xenstore.c | 35 +++++++++++++++++++++++++++-------- 1 file changed, 27 insertions(+), 8 deletions(-) diff --git a/xenstore.c b/xenstore.c index 2a50584f..ac91e204 100644 --- a/xenstore.c +++ b/xenstore.c @@ -190,17 +190,36 @@ static void xenstore_get_backend_path(char **backend, const char *devtype, backend_dompath = xs_get_domain_path(xsh, domid_backend); if (!backend_dompath) goto out; - if (pasprintf(&expected_backend, "%s/backend/%s/%lu/%s", - backend_dompath, devtype, frontend_domid, inst_danger) - == -1) goto out; + const char *expected_devtypes[3]; + const char **expected_devtype = expected_devtypes; + + *expected_devtype++ = devtype; + if (!strcmp(devtype, "vbd")) *expected_devtype++ = "tap"; + *expected_devtype = 0; + assert(expected_devtype < + expected_devtypes + ARRAY_SIZE(expected_devtypes)); + + for (expected_devtype = expected_devtypes; + *expected_devtype; + expected_devtype++) { + + if (pasprintf(&expected_backend, "%s/backend/%s/%lu/%s", + backend_dompath, *expected_devtype, + frontend_domid, inst_danger) + == -1) goto out; - if (strcmp(bpath, expected_backend)) { - fprintf(stderr, "frontend `%s' expected backend `%s' got `%s'," - " ignoring\n", frontend_path, expected_backend, bpath); - errno = EINVAL; - goto out; + if (!strcmp(bpath, expected_backend)) + goto found; } + fprintf(stderr, "frontend `%s' devtype `%s' expected backend `%s'" + " got `%s', ignoring\n", + frontend_path, devtype, expected_backend, bpath); + errno = EINVAL; + goto out; + + found: + if (pasprintf(&backend_frontend_path, "%s/frontend", bpath) == -1) goto out; -- 2.39.5