Re: [Libguestfs] [PATCH v3.1 7/9] New API: swap_set_uuid_random

-----Original Message----- From: libguestfs-bounces(a)redhat.com [mailto:libguestfs-bounces@redhat.com] On Behalf Of Pino Toscano Sent: Friday, June 26, 2015 9:01 PM To: libguestfs(a)redhat.com Subject: Re: [Libguestfs] [PATCH v3.1 7/9] New API: swap_set_uuid_random In data venerdì 26 giugno 2015 17:35:42, Chen Hanxiao ha scritto: > Also introduce get_random_uuid() > > Signed-off-by: Chen Hanxiao <chenhanxiao(a)cn.fujitsu.com&gt; > --- > daemon/daemon.h | 2 ++ > daemon/swap.c | 32 ++++++++++++++++++++++++++++++++ > 2 files changed, 34 insertions(+) > > diff --git a/daemon/daemon.h b/daemon/daemon.h > index 9c8476c..6c07c6a 100644 > --- a/daemon/daemon.h > +++ b/daemon/daemon.h > @@ -278,6 +278,8 @@ extern char *ntfs_get_label (const char *device); > > /*-- in swap.c --*/ > extern int swap_set_uuid (const char *device, const char *uuid); > +extern int swap_set_uuid_random (const char *device); > +extern char *get_random_uuid (void); > > /* ordinary daemon functions use these to indicate errors > * NB: you don't need to prefix the string with the current command, > diff --git a/daemon/swap.c b/daemon/swap.c > index 26fe30d..923adb2 100644 > --- a/daemon/swap.c > +++ b/daemon/swap.c > @@ -34,6 +34,7 @@ GUESTFSD_EXT_CMD(str_mkswap, mkswap); > GUESTFSD_EXT_CMD(str_swapon, swapon); > GUESTFSD_EXT_CMD(str_swapoff, swapoff); > GUESTFSD_EXT_CMD(str_swaplabel, swaplabel); > +GUESTFSD_EXT_CMD(str_uuidgen, uuidgen); > > /* Confirmed this is true for Linux swap partitions from the Linux sources. */ > #define SWAP_LABEL_MAX 16 > @@ -255,3 +256,34 @@ swap_set_uuid (const char *device, const char *uuid) > > return 0; > } > + > +char * > +get_random_uuid (void) > +{ > + int r; > + char *out; > + CLEANUP_FREE char *err = NULL; > + > + r = command (&out, &err, str_uuidgen, NULL); > + if (r == -1) { > + reply_with_error ("%s", err); > + return NULL; > + } > + > + /* caller free */ > + return out; > + > +} The addition of the get_random_uuid() is worth an own commit. Also, it is not specific to swap, so I'd say to put it directly in guestfsd.c, named like uuidgen() (much like the OCaml equivalent in Common_utils). Furthermore, you should make sure uuidgen is actually in the appliance: while in Fedora is in util-linux (already part of the appliance), e.g. in Debian/Ubuntu is in uuid-runtime. Thus you need to add that package to the Debian ones in appliance/packagelist.in.

> +int > +swap_set_uuid_random (const char *device) > +{ > + CLEANUP_FREE char *err = NULL; > + CLEANUP_FREE char *uuid_random = NULL; > + > + uuid_random = get_random_uuid (); > + if (uuid_random == NULL) > + return -1; > + > + return swap_set_uuid (device, uuid_random); > +} This is nothing specific for swap, and could just be done directly in the set_uuid_random implementation, for all the filesystems we have tools to change their UUIDs (so swap only so far). In practice something like: else if (STREQ (vfs_type, "swap")) { CLEANUP_FREE char *uuid = uuidgen (); if (uuid == NULL) return -1; r = swap_set_uuid (device, uuid); }