On 2023-05-24 02:33, Chris Johns wrote:
On 24/5/2023 9:13 am, Chris Johns wrote:
On 23/5/2023 5:30 pm, Christian MAUDERER wrote:
Hello Chris,
On 2023-05-23 08:53, Chris Johns wrote:
On 23/5/2023 4:25 pm, Christian MAUDERER wrote:
Hello Chris,
On 2023-05-23 03:36, Chris Johns wrote:
Hi,
I have been resolving this by adding:
#define preset_mask *preset_mask_prealloc
#define active_mask *active_mask_prealloc
as the assignment logic works as is. It does not catch FD_ZERO which is a shame
but is helps avoid us adding a special case.
Thanks for the suggestion. I used that solution already in the file during the
initial port. But it doesn't work in this case (and maybe we should check other
cases in libbsd too). It only copies the first element of the array of fd_sets.
The variables / defines are (in the patched version - see [1]):
static fd_set *allocated_preset_mask, *allocated_active_mask;
static struct fd_monitor *allocated_fd_monitors;
#define preset_mask (*allocated_preset_mask)
#define active_mask (*allocated_active_mask)
#define fd_monitors (allocated_fd_monitors)
They are allocated as follows (see [2]):
allocated_preset_mask = calloc(sizeof(fd_set),
howmany(rtems_libio_number_iops, sizeof(fd_set) * 8));
allocated_active_mask = calloc(sizeof(fd_set),
howmany(rtems_libio_number_iops, sizeof(fd_set) * 8));
allocated_fd_monitors = calloc(
rtems_libio_number_iops, sizeof(struct fd_monitor));
So basically it's a bunch of arrays of fd_sets. If I now use the following
(unpatched) assignment:
active_mask = preset_mask;
After the preprocessor the line will be
(*allocated_active_mask) = (*allocated_preset_mask);
Which copies only the first element. That's why I had to add the memcpy. Did I
miss some better solution?
I am using this in ntpd which I checked yesterday:
#ifdef __rtems__
#include <rtems/libio_.h>
static size_t rtems_ntpd_fds_size;
static int rtems_fd_set_alloc(fd_set **setp) {
if (*setp == NULL) {
rtems_ntpd_fds_size = sizeof(fd_set) *
(howmany(rtems_libio_number_iops, sizeof(fd_set) * 8));
*setp = malloc(rtems_ntpd_fds_size);
if (*setp == NULL) {
errno = ENOMEM;
return -1;
}
memset(*setp, 0, rtems_ntpd_fds_size);
}
return 0;
}
#define activefds (*activefds_prealloc)
static fd_set *activefds_prealloc;
#define rtems_activefds_alloc() rtems_fd_set_alloc(&activefds_prealloc)
#else /* __rtems__ */
static fd_set activefds;
#endif /* __rtems__ */
and:
#if __rtems__
#define rdfdes (*rdfdes_prealloc)
static fd_set *rdfdes_prealloc;
#else /* __rtems__ */
fd_set rdfdes;
#endif /* __rtems__ */
int nfound;
#if __rtems__
if (rtems_fd_set_alloc(&rdfdes_prealloc) < 0) {
return;
}
memset(rdfdes_prealloc, 0, rtems_ntpd_fds_size);
#else /* __rtems__ */
FD_ZERO(&set);
#endif /* __rtems__ */
with:
++handler_calls;
rdfdes = activefds;
But isn't that line resolving to
(*rdfdes_prealloc) = (*activefds_prealloc);
That would also copy only the first element.
Stepping:
Thread 9 hit Breakpoint 1, _ntp_io_handler () at
../../bsd/freebsd/contrib/ntp/ntpd/ntp_io.c:3727
3727 rdfdes = activefds;
(gdb) x /8bx activefds_prealloc
0x1083e650: 0x20 0x44 0x05 0x20 0x00 0x40 0x00 0x00
(gdb) x /8bx rdfdes_prealloc
0x108353a0: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
(gdb) n
3736 t1.tv_usec = 0;
(gdb) x /8bx rdfdes_prealloc
0x108353a0: 0x20 0x44 0x05 0x20 0x00 0x40 0x00 0x00
Looks ok to me.
fd_set is 64 bit wide. So a copy of the first 64 bit works. Does it still work
if you have 256 files in the system?
Good question. I have not checked but I will.
FYI EPICS has set its limit to 64 because of this issue with select. I suspect
they do not want to hack their select calls like this and I understand them
taking that position.
Yes, I see the issue. The equate only works if the file ops count is the same as
the newlib defined fd_set.
Chris
Thanks for the confirmation. Do you see a better solution than the
memcpy in my patch?
Best regards
Christian
--
--------------------------------------------
embedded brains GmbH & Co. KG
Herr Christian MAUDERER
Dornierstr. 4
82178 Puchheim
Germany
email: christian.maude...@embedded-brains.de
phone: +49-89-18 94 741 - 18
mobile: +49-176-152 206 08
Registergericht: Amtsgericht München
Registernummer: HRA 117265
Vertretungsberechtigte Geschäftsführer: Peter Rasmussen, Thomas Dörfler
Unsere Datenschutzerklärung finden Sie hier:
https://embedded-brains.de/datenschutzerklaerung/
_______________________________________________
devel mailing list
devel@rtems.org
http://lists.rtems.org/mailman/listinfo/devel
