Re: [libvirt] [PATCH v3] storage: Check for invalid storage mode before opening

If a directory pool contains pipes or sockets, a pool start can fail or hang: https://bugzilla.redhat.com/show_bug.cgi?id=589577 We already try to avoid these special files, but only attempt after opening the path, which is where the problems lie. Unify volume opening into helper functions, which use the proper open() flags to avoid error, followed by fstat to validate storage mode. --- a/src/storage/storage_backend.c +++ b/src/storage/storage_backend.c @@ -872,6 +872,61 @@ virStorageBackendForType(int type) { return NULL; } +static int +virStorageBackendVolOpenInternal(const char *path) +{ + int fd; + struct stat sb; + + if ((fd = open(path, O_RDONLY|O_NONBLOCK|O_NOCTTY)) < 0) { + virReportSystemError(errno, + _("cannot open volume '%s'"), + path); + return -1; + } + + if (fstat(fd, &sb) < 0) { + virReportSystemError(errno, + _("cannot stat file '%s'"), + path); + close(fd); + return -1; + } + + if (!S_ISREG(sb.st_mode) && + !S_ISCHR(sb.st_mode) && + !S_ISBLK(sb.st_mode)) { + close(fd); + return -2; + } + + return fd; +} + +/* + * Allows caller to silently ignore files with improper mode + * + * Returns -1 on error, -2 if file mode is unexpected. + */ +int virStorageBackendVolOpenModeSkip(const char *path) +{ + return virStorageBackendVolOpenInternal(path); +} + +int +virStorageBackendVolOpen(const char *path)