initramfs-tools.8: Document mkinitramfs and init env variables.

Documentation currently lacked a list of exported variables
for boot or hook scripts.

(closes: #512453)

Reported-by: Arnaud Fontaine <arnau@debian.org>

1 files changed, 66 insertions, 1 deletions

diff --git a/initramfs-tools.8 b/initramfs-tools.8
index 6bdd5fe..9ef8063 100644
--- a/initramfs-tools.8
+++ b/initramfs-tools.8
@@ -1,4 +1,4 @@
-.TH INITRAMFS-TOOLS 8  "2009/01/07" "Linux" "mkinitramfs script overview"
+.TH INITRAMFS-TOOLS 8  "2009/02/17" "Linux" "mkinitramfs script overview"
 
 .SH NAME
 initramfs-tools \- an introduction to writing scripts for mkinitramfs
@@ -226,6 +226,36 @@ and copy them to the initramfs. This means that most executables, unless
 compiled with klibc, will automatically include glibc in the image which will
 increase its size by several hundred kilobytes.
 
+.SS Exported variables
+mkinitramfs sets several variables for the hook scripts environment.
+
+.TP
+\fB\fI MODULESDIR
+corresponds to the linux-2.6 modules dir.
+.TP
+\fB\fI version
+is the $(uname -r) linux-2.6 version against mkinitramfs is run.
+.TP
+\fB\fI CONFDIR
+is the path of the used initramfs-tools configurations.
+.TP
+\fB\fI DESTDIR
+is the root path of the newly build initramfs.
+.TP
+\fB\fI DPKG_ARCH
+allows arch specific hook additions.
+.TP
+\fB\fI verbose
+corresponds to the verbosity of the update-initramfs run.
+.TP
+\fB\fI KEYMAP
+sets if a keymap needs to be added to initramfs.
+.TP
+\fB\fI MODULES
+specifies which kind of modules should land on initramfs.
+This setting shouldn't be overriden by hook script, but can guide them
+on how much they need to include on initramfs.
+
 
 .SH BOOT SCRIPTS
 
@@ -452,6 +482,41 @@ exit 0
 .fi
 .RE
 
+.SS Exported variables
+init sets several variables for the boot scripts environment.
+
+.TP
+\fB\fI ROOT
+correponds to the root boot option.
+Advanced boot scripts like cryptsetup or live-initramfs need to play tricks.
+Otherwise keep it alone.
+.TP
+\fB\fI ROOTDELAY, ROOTFLAGS, ROOTFSTYPE
+correponds to the rootdelay, rootflags or rootfstype boot option.
+.TP
+\fB\fI DPKG_ARCH
+allows arch specific boot actions.
+.TP
+\fB\fI blacklist, panic, quiet, resume, noresume, resume_offset
+set according relevant boot option.
+.TP
+\fB\fI break
+Useful for manual intervention during setup and coding an boot script.
+.TP
+\fB\fI init
+passes the path to init(8) usually /sbin/init.
+.TP
+\fB\fI readonly
+is the default for mounting the root corresponds to the ro bootarg.
+Overriden by rw bootarg.
+.TP
+\fB\fI rootmnt
+is the path where root gets mounted usualy /root.
+.TP
+\fB\fI debug
+indicates that a debug log is captured for further investigation.
+
+
 .SH DEBUG
 It is easy to check the generated initramfs for its content. One may need
 to double-check if it contains the relevant binaries, libs or modules: