search for: tmpdiskxxxxxx

An evolution of v1 here: https://www.redhat.com/archives/libguestfs/2020-April/msg00035.html I want to generalize the tmpdisk plugin, particularly so you can use commands like ‘qemu-img create’ or even ‘virt-builder’. (Actually virt-builder really works - I tested it - but of course it causes a 30+ second delay when connecting to the server.) You can now use commands such as: nbdkit tmpdisk

...stat statbuf; h = malloc (sizeof *h); if (h == NULL) { @@ -228,36 +264,25 @@ tmpdisk_open (int readonly) goto error; } h->fd = -1; + h->size = -1; h->can_punch_hole = true; - /* Create the new disk image for this connection. */ - if (asprintf (&disk, "%s/tmpdiskXXXXXX", tmpdir) == -1) { + /* For security reasons we have to create a temporary directory + * under tmpdir that only the current user can access. If we + * created it in a shared directory then another user might be able + * to see the temporary file being created and interfere with it +...

...stat statbuf; h = malloc (sizeof *h); if (h == NULL) { @@ -228,36 +292,25 @@ tmpdisk_open (int readonly) goto error; } h->fd = -1; + h->size = -1; h->can_punch_hole = true; - /* Create the new disk image for this connection. */ - if (asprintf (&disk, "%s/tmpdiskXXXXXX", tmpdir) == -1) { + /* For security reasons we have to create a temporary directory + * under tmpdir that only the current user can access. If we + * created it in a shared directory then another user might be able + * to see the temporary file being created and interfere with it +...

v2 was here: https://www.redhat.com/archives/libguestfs/2020-April/msg00075.html In v3: - Add [VAR=VALUE ...] to manual. - Various minor improvements to the manual. - Work (at least, in theory - not tested) with block devices or symlinks. I didn't document this because it's hard to ensure these files or block devices would be cleaned up, so here be dragons. - Remove O_NOCTTY. -

...} - h->fd = -1; - h->size = -1; - h->can_punch_hole = true; /* For security reasons we have to create a temporary directory * under tmpdir that only the current user can access. If we @@ -303,20 +251,20 @@ tmpdisk_open (int readonly) */ if (asprintf (&dir, "%s/tmpdiskXXXXXX", tmpdir) == -1) { nbdkit_error ("asprintf: %m"); - goto error; + goto error0; } if (mkdtemp (dir) == NULL) { nbdkit_error ("%s: %m", dir); - goto error; + goto error0; } if (asprintf (&disk, "%s/disk", dir) == -1) { nbdk...

...h = malloc (sizeof *h); > + if (h == NULL) { > + nbdkit_error ("malloc: %m"); > + goto error; > + } > + h->fd = -1; > + h->can_punch_hole = true; > + > + /* Create the new disk image for this connection. */ > + if (asprintf (&disk, "%s/tmpdiskXXXXXX", tmpdir) == -1) { [2]...here, a user-supplied TMPDIR may require shell-quoting at the points above. > + nbdkit_error ("asprintf: %m"); > + goto error; > + } > + > + h->fd = mkstemp (disk); [3]...ouch - we are not using mkostemp() to atomically set FD_CL...

...ir) + tmpdir = "/var/tmp"; + + h = malloc (sizeof *h); + if (h == NULL) { + nbdkit_error ("malloc: %m"); + goto error; + } + h->fd = -1; + h->can_punch_hole = true; + + /* Create the new disk image for this connection. */ + if (asprintf (&disk, "%s/tmpdiskXXXXXX", tmpdir) == -1) { + nbdkit_error ("asprintf: %m"); + goto error; + } + + h->fd = mkstemp (disk); + if (h->fd == -1) { + nbdkit_error ("mkstemp: %m"); + goto error; + } + + /* Truncate the disk to a sparse file of the right size. */ + if (ftruncate (...

Unfinished (needs tests). This is my attempt to make a "remote tmpfs" plugin as outlined in this prior email: https://www.redhat.com/archives/libguestfs/2020-March/msg00134.html Although it would be possible to construct something a bit like this using existing plugins and filters (perhaps with some new features in those filters) I think it may be nicer to have a dedicated plugin for

v2 was here: https://www.redhat.com/archives/libguestfs/2020-March/msg00154.html v3: - Micro-optimize tmpdir. - Quote $disk in default command shell fragment. - Don't redirect mkfs output to /dev/null. Instead use exec </dev/null >/dev/null before the shell fragment. We may want to do this in other places where we run external shell scripts, or more generally for all

Needs some work still, see in particular the commit message for patch 3. Rich.