On 14-08-07 06:23 AM, Marek Vasut wrote:
On Thursday, August 07, 2014 at 02:28:13 AM, Steve Rae wrote:
On 14-08-06 05:13 PM, Marek Vasut wrote:
On Thursday, August 07, 2014 at 01:48:06 AM, Steve Rae wrote:
On 14-07-30 06:37 PM, Marek Vasut wrote:
On Thursday, June 26, 2014 at 10:13:22 PM, Steve Rae wrote:
[...]
+
+#include <common.h>
+#include <fb_mmc.h>
+#include <part.h>
+#include <sparse_format.h>
+
+/* The 64 defined bytes plus \0 */
+#define RESPONSE_LEN (64 + 1)
+
+static char *response_str;
I'd suggest to pass this "response_str" around instead of making it
global.
That would involve adding it to fastboot_resp(), which is called 11
times in this code, from 3 different functions (so would need to add
this to two of the functions...). And as these evolve, there will likely
be more nested functions, which would all require "passing it
around".... I think that this "static global pointer" is a cleaner
implementation.
Eventually, the amount of these static variables in the code will grow
and it will become increasingly difficult to weed them out. I believe it
would be even better to pass around some kind of a structure with
"private data" of the fastboot, which would cater for all possible
variables which might come in the future. What do you think ?
Yes -- if there is private data that the fastboot implementation
requires, then a data structure is the way to go. However, I still think
that this "fastboot response string" would even be an exception to that
private data....
OK, let's leave it this way for now.
+static void fastboot_resp(const char *s)
+{
+ strncpy(response_str, s, RESPONSE_LEN);
+ response_str[RESPONSE_LEN - 1] = '\0';
This could be shrunk to a single snprintf(response_str,
RESPONSE_LENGTH, s); I think, but I'm not sure if the overhead won't
grow.
snprintf() is used very sparingling in U-Boot
This is not a reason to avoid it.
true....
, and with the cautionary statements in README (line 852)
Which statements? Can you please point them out? I fail to see them,
sorry.
I was referring to what you mention below...
852 - Safe printf() functions
853 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
854 the printf() functions. These are defined in
855 include/vsprintf.h and include snprintf(), vsnprintf() and
856 so on. Code size increase is approximately 300-500 bytes.
857 If this option is not given then these functions will
858 silently discard their buffer size argument - this means
859 you are not getting any overflow checking in this case.
I really don't see the "cautionary statements" here , no . I see that it
discards the size checking if this CONFIG_SYS_VSNPRINTF is not enabled, but that
does not obstruct the operation of those functions.
I'm really confused: my code ensures that the buffer is not overflowed
and that it is terminated properly. If snprintf() (without
CONFIG_SYS_VSNPRINTF defined) doesn't provide "any overflow checking",
then why would I use it?
and the fact that CONFIG_SYS_VSNPRINTF is not defined for armv7 builds,
I am
not going to use it....
Is it a problem to define it? Also, even without CONFIG_SYS_VSNPRINTF ,
the
functions are still available, see the README:
857 If this option is not given then these functions
will 858 silently discard their buffer size argument -
this means 859 you are not getting any overflow
checking in this case.
I have yet to see some hard-evidence against using safe printing
functions here.
I don't want to be the first to defined it for all of armv7....
Honestly, we should just enable this CONFIG_SYS_VSNPRINTF by default for the
good of humanity and all the things, since this unbounded string handling is
just evil (see how OpenSSL ended up, partly because of that ... and I am just
starting to see the pattern in all the security code). I don't want to go down
that road with U-Boot.
So, would you please cook a separate patch to enable this by default, so it
would spur the right kind of discussion on this matter ?
I will apologize in advance, but I just don't know anything about SPL or
TPL or any other boards (outside of my very limited armv7 and armv8
scope)....
I would be happy to review and test this suggested patch (on our
boards), but would be uncomfortable with proposing this patch.
Please go ahead and submit a patch, and I'll check it!
Thanks, Steve
And I really don't want to define it only only my boards running so that
they can run 'fastboot'
What do you suggest?
See above, thanks !
_______________________________________________
U-Boot mailing list
U-Boot@lists.denx.de
http://lists.denx.de/mailman/listinfo/u-boot
