Re: [libvirt] [PATCH] nodeinfo: Make sure we always reset errno before calling readdir

On 04/10/2014 02:52 PM, Natanael Copa wrote: >>> I suppose we could use helper function to make it more readable: >>> >> int virReaddir(DIR *dirp, struct dirent **ent) >> { >> errno = 0; >> *ent = readdir(dirp); >> if (!*ent && errno) { >> virReportSystemError(errno, _("unable to read directory")) >> return -1; >> } >> return *ent ? 1 : 0; or shorter, return !!*ent; >> } >> >> and used as: >> >> while ((ret = virReaddir(dirp, &entry)) > 0) { >> process entry >> } >> if (ret < 0) >> goto error; > > This looks better yes. > > Should I prepare a new patch with this? And grep for more readdirs? Sure; and while at it, update cfg.mk to add a new syntax check to enforce this style. We've wrapped other awkward standard functions that require errno manipulation for correct use (such as strtol and getpwuid_r), precisely because code is more maintainable when we can enforce that the awkward functions are always used correctly.

Food for thought: depending on how many clients you find, it may be worth a version of virReaddir() that takes a flag argument, for auto-filtering '.' and '..' entries.