> On Oct 18, 2017, at 9:31 PM, David Gibson <da...@gibson.dropbear.id.au> wrote:
>
> On Wed, Oct 18, 2017 at 06:31:16PM -0400, John Arbuckle wrote:
>> Implement the strnlen() function if it isn't implemented.
>>
>> Signed-off-by: John Arbuckle <programmingk...@gmail.com>
>
> Nice idea, but this won't work.
>
>> ---
>> libfdt/fdt_ro.c | 24 ++++++++++++++++++++++++
>> 1 file changed, 24 insertions(+)
>>
>> diff --git a/libfdt/fdt_ro.c b/libfdt/fdt_ro.c
>> index 3d00d2e..a7986fb 100644
>> --- a/libfdt/fdt_ro.c
>> +++ b/libfdt/fdt_ro.c
>> @@ -55,6 +55,30 @@
>>
>> #include "libfdt_internal.h"
>>
>> +/* if the current environment does not define strnlen */
>> +#ifndef strnlen
>
> This will only trigger if strnlen is defined as a macro. The C
> library (or other environment) *might* do that, but there's no
> guarantee, whether or not it defines strnlen as a function. With
> extra complications if the compiler has a strnlen builtin like gcc.
:(
>> +
>> +/* This eliminates the missing prototype warning */
>> +int strnlen(const char *string, int max_count);
>> +
>> +/*
>> + * strnlen: return the length of a string or max_count
>> + * which ever is shortest
>> + */
>> +
>> +int strnlen(const char *string, int max_count)
>
> Also strnlen is supposed to take and return size_t, not int.
Will change this.
>
>> +{
>> + int count;
>> + for(count = 0; count < max_count; count++) {
>> + if (string[count] == '\0') {
>> + break;
>> + }
>> + }
>> + return count;
>> +}
>> +
>> +#endif /* strnlen */
>> +
>> static int _fdt_nodename_eq(const void *fdt, int offset,
>> const char *s, int len)
>> {
>
> In any case, this sort of compatibility munging is the job of
> libfdt_env.h. It's purpose is to provide all the external things that
> libfdt needs - there's not that many of them and strnlen() is one.
> The included libfdt_env.h is intended for POSIXy userspace
> environments, which should already include strnlen() in string.h.
QEMU supports Mac OS 10.5 and higher. The strnlen() function might have been
added to Mac OS X in version 10.7. libfdt prevents QEMU from compiling on Mac
OS X because of the missing strnlen() function. This issue needs to be
resolved. If libfdt_env.h is where you want a fix located, would something like
this be good:
#ifdef __APPLE__
#if (MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_7)
size_t strnlen(const char *string, int max_count)
{
... // pretend this is implemented
}
#endif
#endif
