Re: [libvirt] [PATCH 15/20] Provide missing passphrase when creating a volume.

On Thu, Aug 20, 2009 at 08:18:13PM +0200, Miloslav Trma?? wrote: > If the <encryption format='qcow'> element does not specify a secret > during volume creation, generate a suitable secret and add it to the > <encryption> tag. The caller can view the updated <encryption> tag > using virStorageVolGetXMLDesc(). > > Similarly, when <encryption format='default'/> is specified while > creating a qcow or qcow2-formatted volume, change the format to "qcow" > and generate a secret as described above.

> + virBufferAddLit(&buf, "<secret ephemeral='no' private='no'>"); > + /* <uuid/> is chosen by the secret driver */ > + virBufferEscapeString(&buf, > + "<description>qcow passphrase for %s</description>", > + vol->target.path); > + virBufferEscapeString(&buf, "<volume>%s</volume>", vol->target.path); > + virBufferAddLit(&buf, "</secret>"); > + if (virBufferError(&buf)) { > + virReportOOMError(conn); > + goto cleanup; > + } > + xml = virBufferContentAndReset(&buf); This is the first place where we should be just calling into an internal secret_conf.h API for formatting XML from a struct, rather than duplicating the XML formatting.

> + /* A qcow passphrase is up to 16 bytes, with any data following a NUL > + ignored. Prohibit control and non-ASCII characters to avoid possible > + unpleasant surprises with the qemu monitor input mechanism. */ > + fd = open("/dev/urandom", O_RDONLY); > + if (fd < 0) { > + virStorageReportError(conn, VIR_ERR_INTERNAL_ERROR, "%s", > + _("Cannot open /dev/urandom")); > + goto cleanup; > + } > + i = 0; > + while (i < sizeof (value)) { > + ssize_t r; > + > + while ((r = read(fd, value + i, 1)) == -1 && errno == EINTR) > + ; > + if (r <= 0) { > + virStorageReportError(conn, VIR_ERR_INTERNAL_ERROR, "%s", > + _("Cannot read from /dev/urandom")); > + goto cleanup; > + } > + if (value[i] >= 0x20 && value[i] <= 0x7E) > + i++; /* Got an acceptable character */ > + } > + close(fd); I reckon this snippet of code could usefully be put into the util.h file as virFileGenerateRandomkey(), or alternatively perhaps secret_conf.h, as virSecretGenerateRandomKey(unsigned char *buf, size_t buflen);