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>

1 files changed, 11 insertions, 14 deletions

diff --git a/common/dlmalloc.c b/common/dlmalloc.c
index 2276532..ae5702d 100644
--- a/common/dlmalloc.c
+++ b/common/dlmalloc.c
@@ -222,7 +222,6 @@
 
 
 
-
 /* Preliminaries */
 
 #ifndef __STD_C
@@ -935,10 +934,10 @@ struct mallinfo mALLINFo();
 #endif
 
 /* ---------- To make a malloc.h, end cutting here ------------ */
-#else				/* Moved to malloc.h */
+#endif	/* 0 */			/* Moved to malloc.h */
 
 #include <malloc.h>
-#if 0
+#ifdef DEBUG
 #if __STD_C
 static void malloc_update_mallinfo (void);
 void malloc_stats (void);
@@ -946,9 +945,7 @@ void malloc_stats (void);
 static void malloc_update_mallinfo ();
 void malloc_stats();
 #endif
-#endif	/* 0 */
-
-#endif	/* 0 */			/* Moved to malloc.h */
+#endif	/* DEBUG */
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -1618,9 +1615,9 @@ static struct mallinfo current_mallinfo = {  0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
 
 /* Tracking mmaps */
 
-#if 0
+#ifdef DEBUG
 static unsigned int n_mmaps = 0;
-#endif	/* 0 */
+#endif	/* DEBUG */
 static unsigned long mmapped_mem = 0;
 #if HAVE_MMAP
 static unsigned int max_n_mmaps = 0;
@@ -3101,7 +3098,7 @@ size_t malloc_usable_size(mem) Void_t* mem;
 
 /* Utility to update current_mallinfo for malloc_stats and mallinfo() */
 
-#if 0
+#ifdef DEBUG
 static void malloc_update_mallinfo()
 {
   int i;
@@ -3139,7 +3136,7 @@ static void malloc_update_mallinfo()
   current_mallinfo.keepcost = chunksize(top);
 
 }
-#endif	/* 0 */
+#endif	/* DEBUG */
 
 
 
@@ -3158,7 +3155,7 @@ static void malloc_update_mallinfo()
 
 */
 
-#if 0
+#ifdef DEBUG
 void malloc_stats()
 {
   malloc_update_mallinfo();
@@ -3173,19 +3170,19 @@ void malloc_stats()
 	  (unsigned int)max_n_mmaps);
 #endif
 }
-#endif	/* 0 */
+#endif	/* DEBUG */
 
 /*
   mallinfo returns a copy of updated current mallinfo.
 */
 
-#if 0
+#ifdef DEBUG
 struct mallinfo mALLINFo()
 {
   malloc_update_mallinfo();
   return current_mallinfo;
 }
-#endif	/* 0 */
+#endif	/* DEBUG */