Commit graph

34 commits

Author SHA1 Message Date
Lukasz Majewski
0226d8780b env: import: hashtable: Free memory allocated before exiting from himport_r()
ithout this patch memory is not released on early exit.

Signed-off-by: Lukasz Majewski <l.majewski@majess.pl>
2015-09-15 15:05:13 -04:00
Lukasz Majewski
817e48d8a2 env: import: hashtable: Prevent buffer overrun when importing environment from file
Lets consider following scenario:
- One uses echo -n "key=value" to define environment variable in a file (single variable)
- The file content is "key=value" without any terminating byte (e.g. 0x0a or
0x0d).
- The file is loaded to u-boot non zero'ed RAM buffer (with load command).
- Then "env import -t -r $loadaddr $filesize" is executed.
- Due to lack of proper termination byte we have classical example of buffer
  overrun.

This patch prevents from this by allocating one extra byte than size and
explicitly null terminate it.

There should be no change for normal env import operation after applying
this patch.

Signed-off-by: Lukasz Majewski <l.majewski@majess.pl>
2015-09-15 15:05:08 -04:00
Alexander Holler
ecd1446fe1 Add option -r to env import to allow import of text files with CRLF as line endings
When this option is enabled, CRLF is treated like LF when importing environments
from text files, which means CRs ('\r') in front of LFs ('\n') are just ignored.

Drawback of enabling this option is that (maybe exported) variables which have
a trailing CR in their content will get imported without that CR. But this
drawback is very unlikely and the big advantage of letting Windows user create
a *working* uEnv.txt too is likely more welcome.

Signed-off-by: Alexander Holler <holler@ahsoftware.de>
2014-07-22 07:44:26 -04:00
Pierre Aubert
9a8323311c env: fix the env export varname
The env export command doesn't export the first variable of the list
since commit 5a31ea04c9
"env grep" - reimplement command using hexport_r()

Signed-off-by: Pierre Aubert <p.aubert@staubli.com>
2013-11-08 15:25:14 -05:00
Robert P. J. Day
1bce2aeb6f Cosmetic: Fix a number of typos, no functional changes.
Fix various misspellings of things like "environment", "kernel",
"default" and "volatile", and throw in a couple grammar fixes.

Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
2013-09-20 10:30:54 -04:00
Wolfgang Denk
eee479cf6a Add LGPL-2.1+ SPDX-License-Identifier to source files
Signed-off-by: Wolfgang Denk <wd@denx.de>
2013-07-24 09:45:01 -04:00
Lucian Cojocar
e4fdcadd8a env: throw an error when an empty key is used
If the environment contains an entry like "=value" "\0" we should throw
an error when parsing the environment. Otherwise, U-Boot will enter in
an infinite loop.

Signed-off-by: Lucian Cojocar <cojocar@gmail.com>
2013-05-09 17:03:05 -04:00
Wolfgang Denk
be29df6a1a "env grep" - add support for regular expression matches
When CONFIG_REGEX is enabled, the new option "-e" becomes available
which causes regular expression matches to be used.  This allows for
example things like these:

- print all MAC addresses:

	=> env grep -e eth.*addr
	eth1addr=00:10:ec:80:c5:15
	ethaddr=00:10:ec:00:c5:15

- print all variables that have at least 2 colons in their value:

	=> env grep -v -e :.*:
	addip=setenv bootargs ${bootargs} ip=${ipaddr}:${serverip}:${gatewayip}:${netmask}:${hostname}:${netdev}:off
	panic=1
	eth1addr=00:10:ec:80:c5:15
	ethaddr=00:10:ec:00:c5:15
	ver=U-Boot 2013.04-rc1-00289-g497746b-dirty (Mar 22 2013 - 12:50:25)

etc.

Signed-off-by: Wolfgang Denk <wd@denx.de>
2013-05-01 16:24:00 -04:00
Wolfgang Denk
5a31ea04c9 "env grep" - reimplement command using hexport_r()
Also drop hstrstr_r() which is not needed any more.
The new code is way more flexible.

Signed-off-by: Wolfgang Denk <wd@denx.de>
2013-05-01 16:24:00 -04:00
Wolfgang Denk
ea009d4743 hashtable: preparations to use hexport_r() for "env grep"
The output of "env grep" is unsorted, and printing is done by a
private implementation to parse the hash table.  We have all the
needed code in place in hexport_r() alsready, so let's use this
instead.  Here we prepare the code for this, without any functional
changes yet.

Signed-off-by: Wolfgang Denk <wd@denx.de>
2013-05-01 16:24:00 -04:00
Joe Hershberger
2598090b7e env: Add environment variable flags
Currently just validates variable types as decimal, hexidecimal,
boolean, ip address, and mac address.

If the entry is not found in the env ".flags", then look in the static
one. This allows the env to override the static definitions, but prevents
the need to have every definition in the environment distracting you.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
2012-12-13 11:46:56 -07:00
Joe Hershberger
170ab11075 env: Add support for callbacks to environment vars
Add support for per-variable callbacks to the "hashtable" functions.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>

!!!fix comment in callback
2012-12-13 11:46:55 -07:00
Joe Hershberger
be11235ab8 env: Hide '.' variables in env print by default
When printing all variables with env print, don't print variables that
begin with '.'.  If env print is called with a '-a' switch, then
include variables that begin with '.' (just like the ls command).

Variables printed explicitly will be printed even without the -a.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
2012-12-13 11:46:55 -07:00
Joe Hershberger
7afcf3a55b env: Refactor apply into change_ok
Move the read of the old value to inside the check function.  In some
cases it can be avoided all together and at the least the code is only
called from one place.

Also name the function and the callback to more clearly describe what
it does.

Pass the ENTRY instead of just the name for direct access to the whole
data structure.

Pass an enum to the callback that specifies the operation being approved.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
2012-12-13 11:46:55 -07:00
Joe Hershberger
3d3b52f258 env: Consolidate common code in hsearch_r()
The same chunk of code was replicated in two places and the following
changes will make that chunk grow a bit, so combine into a static func.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
2012-12-13 11:46:54 -07:00
Joe Hershberger
c4e0057fa7 env: Refactor do_apply to a flag
Use a flag in hsearch_r for insert mode passed from import to allow the
behavior be different based on use.

Now that "do_check" is called for all imports, ensure console init is
complete before updating the console on relocation import

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
2012-12-13 11:46:54 -07:00
Ilya Yanok
7ac2fe2da2 OMAP: networking support for SPL
This patch adds support for networking in SPL. Some devices are
capable of loading SPL via network so it makes sense to load the
main U-Boot binary via network too. This patch tries to use
existing network code as much as possible. Unfortunately, it depends
on environment which in turn depends on other code so SPL size
is increased significantly. No effort was done to decouple network
code and environment so far.

Signed-off-by: Ilya Yanok <ilya.yanok@cogentembedded.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
Signed-off-by: Tom Rini <trini@ti.com>
2012-10-01 10:02:14 -07:00
Gerlando Falauto
d5370febbc env: delete selected vars not present in imported env
When variables explicitly specified on the command line are not present
in the imported env, delete them from the running env.
If the variable is also missing from the running env, issue a warning.

Signed-off-by: Gerlando Falauto <gerlando.falauto@keymile.com>
Reviewed-by: Marek Vasut <marex@denx.de>
2012-09-18 12:01:52 -07:00
Gerlando Falauto
152874b65b env: check and apply changes on delete/destroy
Signed-off-by: Gerlando Falauto <gerlando.falauto@keymile.com>
Reviewed-by: Marek Vasut <marex@denx.de>
2012-09-18 12:01:52 -07:00
Gerlando Falauto
c5983592e9 env: add check/apply logic to himport_r()
Change hashtable so that a callback function will decide whether a
variable can be overwritten, and possibly apply the changes.

So add a new field to struct hsearch_data:

 o "apply" callback function to check whether a variable can be
    overwritten, and possibly immediately apply the changes;
    when NULL, no check is performed.

And a new argument to himport_r():
 o "do_apply": whether to call the apply callback function

NOTE: This patch does not change the current behavior.

Signed-off-by: Gerlando Falauto <gerlando.falauto@keymile.com>
Reviewed-by: Marek Vasut <marex@denx.de>
2012-09-18 12:01:52 -07:00
Gerlando Falauto
348b1f1c60 env: make himport_r() selective on variables
Add 2 new arguments to himport_r():

 o "nvars", "vars": number and list of variables to take into account
   (0 means ALL)

NOTE: This patch does not change the current behaviour.

Signed-off-by: Gerlando Falauto <gerlando.falauto@keymile.com>
Reviewed-by: Marek Vasut <marex@denx.de>
2012-09-18 12:01:52 -07:00
Simon Glass
ff85628674 sandbox: Fix warnings in hashtable.c
This fixes a few printf() strings for size_t which are missing the 'z'
modifier.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Mike Frysinger <vapier@gentoo.org>
2011-11-22 08:40:05 +01:00
Wolfgang Denk
37f2fe7472 env: allow to export only selected variables
New syntax:
	env export [-t | -b | -c] [-s size] addr [var ...]

With this change it is possible to provide a list of variables names
that shall be exported.  Whenno arguments are given, the whole
environment gets exported.

NOTE: The new handling of the "size" argument means a change to the
user API.

Signed-off-by: Wolfgang Denk <wd@denx.de>
2011-11-08 13:20:42 +01:00
Jason Hobbs
4d91a6ecab Replace space and tab checks with isblank
These are various places I found that checked for conditions equivalent
to isblank.

Signed-off-by: Jason Hobbs <jason.hobbs@calxeda.com>
2011-10-17 22:25:34 +02:00
Wolfgang Denk
84b5e8022e Constify getenv(), setenv() and hash code functions
This is needed to get rid of build warnings like

main.c:311: warning: passing argument 2 of 'setenv' discards qualifiers from pointer target type

which result from commit 09c2e90 "unify version_string".

Signed-off-by: Wolfgang Denk <wd@denx.de>
Cc: Andreas Bießmann <andreas.devel@googlemail.com>
2011-07-30 01:37:44 +02:00
Kim Phillips
a000b7950d common: add a grepenv command
u-boot environments, esp. when boards are shared across multiple
users, can get pretty large and time consuming to visually parse.
The grepenv command this patch adds can be used in lieu of printenv
to facilitate searching.  grepenv works like printenv but limits
its output only to environment strings (variable name and value
pairs) that match the user specified substring.

the following examples are on a board with a 5313 byte environment
that spans multiple screen pages:

Example 1:  summarize ethernet configuration:

=> grepenv eth TSEC
etact=FM1@DTSEC2
eth=FM1@DTSEC4
ethact=FM1@DTSEC2
eth1addr=00:E0:0C:00:8b:01
eth2addr=00:E0:0C:00:8b:02
eth3addr=00:E0:0C:00:8b:03
eth4addr=00:E0:0C:00:8b:04
eth5addr=00:E0:0C:00:8b:05
eth6addr=00:E0:0C:00:8b:06
eth7addr=00:E0:0C:00:8b:07
eth8addr=00:E0:0C:00:8b:08
eth9addr=00:E0:0C:00:8b:09
ethaddr=00:E0:0C:00:8b:00
netdev=eth0
uprcw=setenv ethact $eth;setenv filename p4080ds/R_PPSXX_0xe/rcw_0xe_2sgmii_rev2_high.bin;setenv start 0xe8000000;protect off all;run upimage;protect on all
upuboot=setenv ethact $eth;setenv filename u-boot.bin;setenv start eff80000;protect off all;run upimage;protect on all
upucode=setenv ethact $eth;setenv filename fsl_fman_ucode_P4080_101_6.bin;setenv start 0xef000000;protect off all;run upimage;protect on all
usdboot=setenv ethact $eth;tftp 1000000 $dir/$bootfile;tftp 2000000 $dir/initramfs.cpio.gz.uboot;tftp c00000 $dir/p4080ds-usdpaa.dtb;setenv bootargs root=/dev/ram rw console=ttyS0,115200 $othbootargs;bootm 1000000 2000000 c00000;
=>

Example 2: detect unused env vars:

=> grepenv etact
etact=FM1@DTSEC2
=>

Example 3: reveal hardcoded variables; e.g., for fdtaddr:

=> grepenv fdtaddr
fdtaddr=c00000
nfsboot=setenv bootargs root=/dev/nfs rw nfsroot=$serverip:$rootpath ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname:$netdev:off console=$consoledev,$baudrate $othbootargs;tftp $loadaddr $bootfile;tftp $fdtaddr $fdtfile;bootm $loadaddr - $fdtaddr
ramboot=setenv bootargs root=/dev/ram rw console=$consoledev,$baudrate $othbootargs;tftp $ramdiskaddr $ramdiskfile;tftp $loadaddr $bootfile;tftp $fdtaddr $fdtfile;bootm $loadaddr $ramdiskaddr $fdtaddr
=> grep $fdtaddr
fdtaddr=c00000
my_boot=bootm 0x40000000 0x41000000 0x00c00000
my_dtb=tftp 0x00c00000 $prefix/p4080ds.dtb
nohvboot=tftp 1000000 $dir/$bootfile;tftp 2000000 $dir/$ramdiskfile;tftp c00000 $dir/$fdtfile;setenv bootargs root=/dev/ram rw ramdisk_size=0x10000000 console=ttyS0,115200;bootm 1000000 2000000 c00000;
=>

This patch also enables the grepenv command by default on
corenet_ds based boards (and repositions the DHCP command
entry to keep the list sorted).

Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
Cc: Kumar Gala <kumar.gala@freescale.com>
Cc: Andy Fleming <afleming@freescale.com>
2011-04-28 01:00:07 +02:00
Kim Phillips
af4d9074aa env: fix env var autocompletion
commit 560d424b6d "env: re-add
support for auto-completion" fell short of its description -
the 'used' logic in hmatch_r was reversed - 'used' is 0 if
the hash table entry is not used, or -1 if deleted.  This
patch makes hmatch_r actually match on valid ('used') entries,
instead of skipping them and failing to match anything.

typing 'printenv tft' and hitting 'tab' now displays valid
choices for variable names.

Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Tested-by: Mike Frysinger <vapier@gentoo.org>
2011-04-28 00:54:40 +02:00
Peter Barada
c81c122242 Fix hash table deletion to prevent lost entries
Use negative used value to mark deleted entry.  Search keeps probing
past deleted entries.  Adding an entry uses first deleted entry when
it hits end of probe chain.

Initially found that "ramdiskimage" and "preboot" collide modulus 347,
causing "preboot" to be inserted at idx 190, "ramdiskimage" at idx 191.
Previous to this fix when "preboot" is deleted, "ramdiskimage" is
orphaned.

Signed-off-by: Peter Barada <peter.barada@logicpd.com>
Tested-by: Wolfgang Denk <wd@denx.de>
2011-03-22 22:43:04 +01:00
Mike Frysinger
560d424b6d env: re-add support for auto-completion
Currently, only basic completion is supported (no globs), but this is
what we had previously.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-01-09 17:57:37 +01:00
Mike Frysinger
2eb1573f01 hashtable: drop all non-reentrant versions
The non-reentrant versions of the hashtable functions operate on a single
shared hashtable.  So if two different people try using these funcs for
two different purposes, they'll cause problems for the other.

Avoid this by converting all existing hashtable consumers over to the
reentrant versions and then punting the non-reentrant ones.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-12-17 21:07:14 +01:00
Wolfgang Denk
071bc92330 Coding Style cleanup
Signed-off-by: Wolfgang Denk <wd@denx.de>
2010-10-27 22:48:30 +02:00
Andreas Bießmann
fc5fc76bda lib/hashtable.c: add CONFIG_ENV_MIN_ENTRIES
This patch adds a new config parameter for adjusting the calculation of
hash table size when importing a buffer.

When importing a extremely small buffer (e.g. the default_environment)
the old calculation generated a hash table which could hold at most the
buffer content but no more entires.

The new calculation add a fixed number of entries to the result to fit
better for small import buffers. This amount may be configured by the
user in board file to adjust the behaviour.

Signed-off-by: Andreas Bießmann <andreas.devel@googlemail.com>
2010-10-06 22:46:35 +02:00
Wolfgang Denk
ea882baf9c New implementation for internal handling of environment variables.
Motivation:

* Old environment code used a pessimizing implementation:
  - variable lookup used linear search => slow
  - changed/added variables were added at the end, i. e. most
    frequently used variables had the slowest access times => slow
  - each setenv() would calculate the CRC32 checksum over the whole
    environment block => slow
* "redundant" envrionment was locked down to two copies
* No easy way to implement features like "reset to factory defaults",
  or to select one out of several pre-defined (previously saved) sets
  of environment settings ("profiles")
* No easy way to import or export environment settings

======================================================================

API Changes:

- Variable names starting with '#' are no longer allowed

  I didn't find any such variable names being used; it is highly
  recommended to follow standard conventions and start variable names
  with an alphanumeric character

- "printenv" will now print a backslash at the end of all but the last
  lines of a multi-line variable value.

  Multi-line variables have never been formally defined, allthough
  there is no reason not to use them. Now we define rules how to deal
  with them, allowing for import and export.

- Function forceenv() and the related code in saveenv() was removed.
  At the moment this is causing build problems for the only user of
  this code (schmoogie - which has no entry in MAINTAINERS); may be
  fixed later by implementing the "env set -f" feature.

Inconsistencies:

- "printenv" will '\\'-escape the '\n' in multi-line variables, while
  "printenv var" will not do that.

======================================================================

Advantages:

- "printenv" output much better readable (sorted)
- faster!
- extendable (additional variable properties can be added)
- new, powerful features like "factory reset" or easy switching
  between several different environment settings ("profiles")

Disadvantages:

- Image size grows by typically 5...7 KiB (might shrink a bit again on
  systems with redundant environment with a following patch series)

======================================================================

Implemented:

- env command with subcommands:

  - env print [arg ...]

    same as "printenv": print environment

  - env set [-f] name [arg ...]

    same as "setenv": set (and delete) environment variables

    ["-f" - force setting even for read-only variables - not
    implemented yet.]

  - end delete [-f] name

    not implemented yet

    ["-f" - force delete even for read-only variables]

  - env save

    same as "saveenv": save environment

  - env export [-t | -b | -c] addr [size]

    export internal representation (hash table) in formats usable for
    persistent storage or processing:

	-t:	export as text format; if size is given, data will be
		padded with '\0' bytes; if not, one terminating '\0'
		will be added (which is included in the "filesize"
		setting so you can for exmple copy this to flash and
		keep the termination).
	-b:	export as binary format (name=value pairs separated by
		'\0', list end marked by double "\0\0")
	-c:	export as checksum protected environment format as
		used for example by "saveenv" command
	addr:	memory address where environment gets stored
	size:	size of output buffer

	With "-c" and size is NOT given, then the export command will
	format the data as currently used for the persistent storage,
	i. e. it will use CONFIG_ENV_SECT_SIZE as output block size and
	prepend a valid CRC32 checksum and, in case of resundant
	environment, a "current" redundancy flag. If size is given, this
	value will be used instead of CONFIG_ENV_SECT_SIZE; again, CRC32
	checksum and redundancy flag will be inserted.

	With "-b" and "-t", always only the real data (including a
	terminating '\0' byte) will be written; here the optional size
	argument will be used to make sure not to overflow the user
	provided buffer; the command will abort if the size is not
	sufficient. Any remainign space will be '\0' padded.

        On successful return, the variable "filesize" will be set.
        Note that filesize includes the trailing/terminating '\0'
        byte(s).

        Usage szenario: create a text snapshot/backup of the current
	settings:

		=> env export -t 100000
		=> era ${backup_addr} +${filesize}
		=> cp.b 100000 ${backup_addr} ${filesize}

	Re-import this snapshot, deleting all other settings:

		=> env import -d -t ${backup_addr}

  - env import [-d] [-t | -b | -c] addr [size]

    import external format (text or binary) into hash table,
    optionally deleting existing values:

	-d:	delete existing environment before importing;
		otherwise overwrite / append to existion definitions
	-t:	assume text format; either "size" must be given or the
		text data must be '\0' terminated
	-b:	assume binary format ('\0' separated, "\0\0" terminated)
	-c:	assume checksum protected environment format
	addr:	memory address to read from
	size:	length of input data; if missing, proper '\0'
		termination is mandatory

  - env default -f

    reset default environment: drop all environment settings and load
    default environment

  - env ask name [message] [size]

    same as "askenv": ask for environment variable

  - env edit name

    same as "editenv": edit environment variable

  - env run

    same as "run": run commands in an environment variable

======================================================================

TODO:

- drop default env as implemented now; provide a text file based
  initialization instead (eventually using several text files to
  incrementally build it from common blocks) and a tool to convert it
  into a binary blob / object file.

- It would be nice if we could add wildcard support for environment
  variables; this is needed for variable name auto-completion,
  but it would also be nice to be able to say "printenv ip*" or
  "printenv *addr*"

- Some boards don't link any more due to the grown code size:
  DU405, canyonlands, sequoia, socrates.

	=> cc: Matthias Fuchs <matthias.fuchs@esd-electronics.com>,
	       Stefan Roese <sr@denx.de>,
	       Heiko Schocher <hs@denx.de>

- Dropping forceenv() causes build problems on schmoogie

	=> cc: Sergey Kubushyn <ksi@koi8.net>

- Build tested on PPC and ARM only; runtime tested with NOR and NAND
  flash only => needs testing!!

Signed-off-by: Wolfgang Denk <wd@denx.de>
Cc: Matthias Fuchs <matthias.fuchs@esd-electronics.com>,
Cc: Stefan Roese <sr@denx.de>,
Cc: Heiko Schocher <hs@denx.de>
Cc: Sergey Kubushyn <ksi@koi8.net>
2010-09-19 19:29:48 +02:00
Wolfgang Denk
a6826fbc5c Add hash table support as base for new environment code
This implementation is based on code from uClibc-0.9.30.3 but was
modified and extended for use within U-Boot.

Major modifications and extensions:

* hsearch() [modified / extended]:
  - While the standard version does not make any assumptions about
    the type of the stored data objects at all, this implementation
    works with NUL terminated strings only.
  - Instead of storing just pointers to the original objects, we
    create local copies so the caller does not need to care about the
    data any more.
  - The standard implementation does not provide a way to update an
    existing entry.  This version will create a new entry or update an
    existing one when both "action == ENTER" and "item.data != NULL".
  - hsearch_r(): Instead of returning 1 on success, we return the
    index into the internal hash table, which is also guaranteed to be
    positive.  This allows us direct access to the found hash table
    slot for example for functions like hdelete().
* hdelete() [added]:
  - The standard implementation of hsearch(3) does not provide any way
    to delete any entries from the hash table.  We extend the code to
    do that.
* hexport() [added]:
  - Export the data stored in the hash table in linearized form:
    Entries are exported as "name=value" strings, separated by an
    arbitrary (non-NUL, of course) separator character. This allows to
    use this function both when formatting the U-Boot environment for
    external storage (using '\0' as separator), but also when using it
    for the "printenv" command to print all variables, simply by using
    as '\n" as separator. This can also be used for new features like
    exporting the environment data as text file, including the option
    for later re-import.
  - The entries in the result list will be sorted by ascending key
    values.
* himport() [added]:
  - Import linearized data into hash table.  This is the inverse
    function to hexport(): it takes a linear list of "name=value"
    pairs and creates hash table entries from it.
  - Entries without "value", i. e. consisting of only "name" or
    "name=", will cause this entry to be deleted from the hash table.
  - The "flag" argument can be used to control the behaviour: when
    the H_NOCLEAR bit is set, then an existing hash table will kept,
    i. e. new data will be added to an existing hash table;
    otherwise, old data will be discarded and a new hash table will
    be created.
  - The separator character for the "name=value" pairs can be
    selected, so we both support importing from externally stored
    environment data (separated by NUL characters) and from plain text
    files (entries separated by newline characters).
  - To allow for nicely formatted text input, leading white space
    (sequences of SPACE and TAB chars) is ignored, and entries
    starting (after removal of any leading white space) with a '#'
    character are considered comments and ignored.
  - NOTE: this means that a variable name cannot start with a '#'
    character.
  - When using a non-NUL separator character, backslash is used as
    escape character in the value part, allowing for example fo
    multi-line values.
  - In theory, arbitrary separator characters can be used, but only
    '\0' and '\n' have really been tested.

Signed-off-by: Wolfgang Denk <wd@denx.de>
2010-09-19 19:29:47 +02:00