Update live-boot(7) man page and add new one for live.persist(5).

2 files changed, 216 insertions, 2 deletions

diff --git a/manpages/en/live-boot.7 b/manpages/en/live-boot.7
index ad6d1d2..65c9c31 100644
--- a/manpages/en/live-boot.7
+++ b/manpages/en/live-boot.7
@@ -1,4 +1,4 @@
-.TH LIVE\-BOOT 7 2012\-02\-06 3.0~a25-1 "Debian Live Project"
+.TH LIVE\-BOOT 7 2012\-03\-23 3.0~a25-1 "Debian Live Project"
 
 .SH NAME
 \fBlive\-boot\fR \- System Boot Scripts
@@ -107,7 +107,7 @@ This parameters allows to set a custom ramdisk size (it's the '\-o size' option
 .IP "\fBswapon\fR" 4
 This parameter enables usage of local swap partitions.
 .IP "\fBpersistent\fR" 4
-live\-boot will probe filesystems for persistent media. These can either be the filesystems themselves, if labeled correctly, or image/archive files, if named correctly. Overlays are labeled/named either "live\-rw" or "home\-rw" and will be mounted on / or /home, respectively; snapshots are labeled/named either "live\-sn" or "home\-sn" and will be extracted into / or /home, respectively (see live\-snapshot(1) for more information). Overlays are mounted before snapshots are extracted, and for both overlays and snapshots, "live\-*" are handled before "home\-*". Overlay image files and snapshot archive files have extensions which determines their filesystem or archive type, e.g. "live\-rw.ext3" and "\home\-sn.squashfs".
+live\-boot will probe devices for persistent media. These can be partitions (with the correct GPT name), filesystems (with the correct label) or image/archive files (with the correct file name). Overlays are labeled/named either "full\-ov", which will be mounted on /, or "custom\-ov", which can be completely customized (see \fIlive.persist\fR(5)); snapshots are labeled/named either "live\-sn" or "home\-sn" and will be extracted into / or /home, respectively (see \fIlive\-snapshot\fR(1) for more information). The order these are handled are: full\-ov, custom\-ov, live-sn, home-sn. Overlay image files and snapshot archive files have extensions which determines their filesystem or archive type, e.g. "custom\-ov.ext3" and "\home\-sn.squashfs".
 .IP "\fBpersistent\-encryption\fR=\fITYPE1\fR,\fITYPE2\fR ... \fITYPEn\fR" 4
 This option determines which types of encryption that we allow to be used when probing devices for persistent media. If "none" is in the list, we allow unencrypted media; if "luks" is in the list, we allow LUKS\-encrypted media. Whenever a device containing encrypted media is probed the user will be prompted for the passphrase. The default value is "none".
 .IP "\fBpersistent\-media\fR={\fIremovable\fR|\fIremovable\-usb\fR}" 4
@@ -157,10 +157,13 @@ This saves expensive writes and speeds up operations on volatile data such as we
 .IP "\fB/etc/live/boot.d/\fR" 4
 .IP "\fBlive/boot.conf\fR" 4
 .IP "\fBlive/boot.d/\fR" 4
+.IP "\fBlive.persist\fR" 4
 
 .SH SEE ALSO
 \fIlive\-snapshot\fR(1)
 .PP
+\fIlive.persist\fR(5)
+.PP
 \fIlive\-build\fR(7)
 .PP
 \fIlive\-config\fR(7)
diff --git a/manpages/en/live.persist.5 b/manpages/en/live.persist.5
new file mode 100644
index 0000000..eff56da
--- /dev/null
+++ b/manpages/en/live.persist.5
@@ -0,0 +1,211 @@
+.TH LIVE.PERSIST 5 2012\-03\-23 3.0~a25-1 "Debian Live Project"
+
+.SH NAME
+\fBlive.persist\fR \- Configuration file for persistent media in
+live\-boot
+
+.SH DESCRIPTION
+If live-boot probes a persistent volume with the label (or GPT name,
+or file name, but from now on we will just say "label") "custom\-ov",
+that volume's persistence is fully customizable through the
+\fBlive.persist\fR file stored on the root of its file system. Any such
+labeled volume must have such a file, or it will be ignored.
+.PP
+The format of \fBlive.persist\fR allow empty lines and lines starting
+with a "#" (used for comments), both which will be ignored. A so
+called "custom mount" has the format:
+.PP
+.RS
+\fIDIR\fR [\fIOPTION\fR]...
+.RE
+.PP
+which roughly translates to "make \fIDIR\fR persistent in the way
+described by the list of \fIOPTION\fRs".
+.PP
+For each custom mount \fIDIR\fR must be an absolute path that cannot
+contain white spaces or the special . and .. path components, and
+cannot be /live (or any of its sub-directories), or / (for the latter,
+use "full-ov" persistence instead). Once activated all changes (file
+deletion, creation and modification) to \fIDIR\fR on the live file
+system are stored persistently into a path equivalent to \fIDIR\fR on
+the persistent media, called the source directory. The default way to
+achieve persistence is to simply bind-mount the corresponding source
+directory to \fIDIR\fR, but this can be changed through the use of
+\fIOPTION\fRs.
+.PP
+All custom mounts will be done in an order so that no two custom
+mounts can "hide" each other. For instance, if we have the two
+\fIDIR\fR:s /a and /a/b it would always be the case that /a is mounted
+first, then /a/b. This remains true no matter how the lines in
+\fBlive.persist\fR are ordered, or if several \fBlive.persist\fR files
+on different persistent media are used at the same time. However, it
+is forbidden for custom mounts to have their source directory inside
+the source directory of another custom mount, so the source
+directories that are auto-created by live-boot does not support
+"nested" mounts like /a and /a/b on the same media. In this case you
+must use the \fBsource\fR option (see below) to make sure that they
+are stored in different source directories.
+.PP
+When a source directory doesn't exist on the persistent media for a
+certain custom mount, it will be created automatically, and
+permissions and ownership will be optimistically set according to
+\fIDIR\fR. It will also be bootstrapped by copying the contents of the
+\fIDIR\fR into its source directory on the persistent media. The
+bootstrapping will not happen when the \fBlinkfiles\fR or \fBunion\fR
+options are used (see below).
+
+.SH OPTIONS
+Custom mounts defined in \fBlive.persist\fR accept the following
+options in a coma-separated list:
+.IP "\fBsource\fR=\fIPATH\fR" 4
+When given, store the persistent changes into \fIPATH\fR on the
+persistent media. \fIPATH\fR must be a relative path (w.r.t. the
+persistent media root) that cannot contain white spaces or the
+special . or .. path components, with the exception that it can be
+just . which means the persistent media root. This option is mostly
+relevant if you want to nest custom mounts, which otherwise would
+cause errors, or if you want to make the whole media root available
+(similar to the now deprecated \fBhome-rw\fR type of persistence).
+.PP
+The following options will override the default bind-mount behaviour
+of custom mounts, and are mutually exclusive:
+.IP "\fBlinkfiles\fR" 4
+Create the directory structure of the source directory on the
+persistent media in \fIDIR\fR and create symbolic links from the
+corresponding place in \fIDIR\fR to each file in the source directory.
+Existing files or directories with the same name as any link will be
+overwritten. Note that deleting the links in \fIDIR\fR will only
+remove the link, not the corresponding file in the source; removed
+links will reappear after a reboot. To permanently add or delete a
+file one must do so directly in the source directory.
+.IP
+Effectively \fBlinkfiles\fR will make only files already in the source
+directory persistent, not any other files in \fIDIR\fR. These files
+must be manually added to the source directory to make use of this
+option, and they will appear in \fIDIR\fR in addition to files already
+there. This option is useful when only certain files need to be
+persistent, not the whole directory they're in, e.g. some
+configuration files in a user's home directory.
+.IP "\fBunion\fR" 4
+Save the rw branch of a union on the persistent media, so only the
+changes are stored persistently. This can potentially reduce disk
+usage compared to bind-mounts, and will not hide files added to the
+read-only media. One caveat is that the union will use \fIDIR\fR from
+the image's read-only file system, not the real file system root, so
+files created after boot (e.g. by live-config) will not appear in the
+union. This option will use the union file system specified by
+live-boot's \fBunion\fR boot parameter, but is not supported with
+\fBunion=unionmount\fR.
+
+.SH DIRECTORIES
+.IP "\fB/live/persistent\fR" 4
+All persistent volumes will be mounted here (in a directory
+corresponding to the device name). The \fBlive.persist\fR file can
+easily be edited through this mount, as well as any source directories
+(which is especially practical for custom mounts using the
+\fBlinkfiles\fR option).
+
+.SH EXAMPLES
+
+Let's say we have a persistent volume \fIVOL\fR with the a
+\fBlive.persist\fR file containing the following four lines (numbered
+for ease of reference):
+.TP 7
+1.
+/home/user1 linkfiles,source=config-files/user1
+.TP
+2.
+/home/user2 linkfiles,source=config-files/user2
+.TP
+3.
+/home
+.TP
+4.
+/usr union
+.PP
+The corresponding source directories are:
+.TP 7
+1.
+\fIVOL\fR/config-files/user1 (but it would be \fIVOL\fR/home/user1
+without the \fBsource\fR option)
+.TP
+2.
+\fIVOL\fR/config-files/user2 (but it would be \fIVOL\fR/home/user2
+without the \fBsource\fR option)
+.TP
+3.
+\fIVOL\fR/home
+.TP
+4.
+\fIVOL\fR/usr
+.PP
+It was necessary to set the \fBsource\fR options for 1 and 2, since
+they otherwise would become nested with 3's source, which is illegal.
+.PP
+Line 3 will be taken care of before line 1 and 2 in order to prevent
+custom mounts 1 and 2 from being hidden by 3. When line 3 is handled,
+\fIVOL\fR/home is simply bind-mounted on /home. To illustrate what
+happens for lines 1 and 2, let's say that the following files exist:
+.TP 7
+a.
+\fIVOL\fR/config-files/user1/.emacs
+.TP
+b.
+\fIVOL\fR/config-files/user2/.bashrc
+.TP
+c.
+\fIVOL\fR/config-files/user2/.ssh/config
+.PP
+Then the following links and directories will be created:
+.TP 7
+Link:
+/home/user1/.emacs -> \fIVOL\fR/config-files/user1/.emacs (from a)
+.TP
+Link:
+/home/user2/.bashrc -> \fIVOL\fR/config-files/user2/.bashrc (from b)
+.TP
+Dir:
+/homea/user2/.ssh (from c)
+.TP
+Link:
+/home/user2/.ssh/config -> \fIVOL\fR/config-files/user2/.ssh/config
+(from c)
+.PP
+One could argue, though, that lines 1 and 2 in the example
+\fBlive.persist\fR file above are unnecessary since line 3 already
+would make all of /home persistent. The \fBlinkfiles\fR option is
+intended for situations where you don't want a complete directory to
+be persistent, only certain files in it or its sub-directories.
+.PP
+Line 4 can be mounted at any time since its \fIDIR\fR (and source
+directory) is completely disjoint from all the other custom
+mounts. When mounted, \fIVOL\fR/usr will be the rw branch due to the
+\fBunion\fR option, and will only contain the difference compared to
+the underlying read-only file system. Hence packages could be
+installed into /usr with great space-wise efficiency compared to
+bind-mounts, since in the latter case all of /usr would have to be
+copied into \fIVOL\fR/usr during the initial bootstrap.
+
+.SH SEE ALSO
+\fIlive\-boot\fR(7)
+.PP
+\fIlive\-build\fR(7)
+.PP
+\fIlive\-config\fR(7)
+.PP
+\fIlive\-tools\fR(7)
+
+.SH HOMEPAGE
+More information about live\-boot and the Debian Live project can be
+found on the homepage at <\fIhttp://live.debian.net/\fR> and in the
+manual at <\fIhttp://live.debian.net/manual/\fR>.
+
+.SH BUGS
+Bugs can be reported by submitting a bugreport for the live\-boot
+package in the Debian Bug Tracking System at
+<\fIhttp://bugs.debian.org/\fR> or by writing a mail to the Debian
+Live mailing list at <\fIdebian-live@lists.debian.org\fR>.
+
+.SH AUTHOR
+live\-boot was written by anonym <\fIanonym@lavabit.com\fR> for the
+Debian project.