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2010-07-04Make sure that argv[] argument pointers are not modified.Wolfgang Denk
The hush shell dynamically allocates (and re-allocates) memory for the argument strings in the "char *argv[]" argument vector passed to commands. Any code that modifies these pointers will cause serious corruption of the malloc data structures and crash U-Boot, so make sure the compiler can check that no such modifications are being done by changing the code into "char * const argv[]". This modification is the result of debugging a strange crash caused after adding a new command, which used the following argument processing code which has been working perfectly fine in all Unix systems since version 6 - but not so in U-Boot: int main (int argc, char **argv) { while (--argc > 0 && **++argv == '-') { /* ====> */ while (*++*argv) { switch (**argv) { case 'd': debug++; break; ... default: usage (); } } } ... } The line marked "====>" will corrupt the malloc data structures and usually cause U-Boot to crash when the next command gets executed by the shell. With the modification, the compiler will prevent this with an error: increment of read-only location '*argv' N.B.: The code above can be trivially rewritten like this: while (--argc > 0 && **++argv == '-') { char *arg = *argv; while (*++arg) { switch (*arg) { ... Signed-off-by: Wolfgang Denk <wd@denx.de> Acked-by: Mike Frysinger <vapier@gentoo.org>
2009-11-23Add 'true' and 'false' commandsPeter Tyser
These commands are only enabled when the hush shell is enabled and can be useful in scripts such as: while true do echo "Booting OS..."; run $bootcmd; echo "Booting OS failed"; sleep 10; done Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
2009-11-23command.c: Break commands out to appropriate cmd_*.c filesPeter Tyser
command.c should contain common code related to commands, not miscellaneous command implementations. Signed-off-by: Peter Tyser <ptyser@xes-inc.com>