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Message-ID: <e2513e72-5949-463d-a950-0778609141d7@t-8ch.de>
Date: Sun, 29 Jun 2025 17:54:02 +0200
From: Thomas Weißschuh <linux@...ssschuh.net>
To: Willy Tarreau <w@....eu>
Cc: Thomas Weißschuh <thomas.weissschuh@...utronix.de>,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/4] tools/nolibc: move FD_* definitions to sys/select.h
On 2025-06-29 17:10:06+0200, Willy Tarreau wrote:
> On Sun, Jun 29, 2025 at 11:40:48AM +0200, Willy Tarreau wrote:
> > On Sun, Jun 29, 2025 at 11:37:06AM +0200, Thomas Weißschuh wrote:
> > > On 2025-06-29 11:25:52+0200, Willy Tarreau wrote:
> > > > On Sun, Jun 29, 2025 at 10:53:34AM +0200, Thomas Weißschuh wrote:
> > > > > On 2025-06-29 10:46:28+0200, Willy Tarreau wrote:
> > > > > > On Mon, Jun 23, 2025 at 04:56:18AM +0200, Willy Tarreau wrote:
> > >
> > > <snip>
> > >
> > > > > > Trying it has reopened the circular dependencies can of worms :-(
> > > > > > It's the same problem as usual that we've worked around till now
> > > > > > by placing some types in types.h, except that this time fd_set is
> > > > > > defined based on the macros FD_* that I moved to sys/select.h.
> > > > >
> > > > > Can't fd_set also move to sys/select.h? This is how I read fd_set(3).
> > > >
> > > > That was what I did and precisely what was causing the problem. We
> > > > have sys.h defining select() with fd_set in it with sys/select not yet
> > > > being included. I moved sys.h after all sys/* and it broke something
> > > > else instead.
> > >
> > > Ah. Then move select() also into sys/select.h; where it belongs. :-)
> >
> > For an unknown reason I thought we avoided to move the syscall definitions
> > there and only used sys/*, but I was apparently confused as we have exactly
> > that in prctl or wait. I can give that one a try again.
>
> So after one more hour on it, I'm admitting abandonning the battle.
> Adding the necessary includes there is causing "declared inside parameter"
> failures in random other totally unrelated stuff (e.g. in sys_getdents64()
> or msleep()). We'll have to really clear that circular includes mess again
> in a near future. For now I'll stay on the stub which works fine without
> affecting the rest.
I saw the same issue, but only because of the changes to types.h.
And these should not be necessary in the first place.
The below works nicely for me:
diff --git a/tools/include/nolibc/Makefile b/tools/include/nolibc/Makefile
index 3fcee9fe4ece..125dbb2f1388 100644
--- a/tools/include/nolibc/Makefile
+++ b/tools/include/nolibc/Makefile
@@ -56,6 +56,7 @@ all_files := \
sys/random.h \
sys/reboot.h \
sys/resource.h \
+ sys/select.h \
sys/stat.h \
sys/syscall.h \
sys/sysmacros.h \
diff --git a/tools/include/nolibc/nolibc.h b/tools/include/nolibc/nolibc.h
index c199ade200c2..6dc2f2a6cbde 100644
--- a/tools/include/nolibc/nolibc.h
+++ b/tools/include/nolibc/nolibc.h
@@ -104,6 +104,7 @@
#include "sys/random.h"
#include "sys/reboot.h"
#include "sys/resource.h"
+#include "sys/select.h"
#include "sys/stat.h"
#include "sys/syscall.h"
#include "sys/sysmacros.h"
diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h
index 9556c69a6ae1..ae4b0970b570 100644
--- a/tools/include/nolibc/sys.h
+++ b/tools/include/nolibc/sys.h
@@ -745,53 +745,6 @@ int sched_yield(void)
}
-/*
- * int select(int nfds, fd_set *read_fds, fd_set *write_fds,
- * fd_set *except_fds, struct timeval *timeout);
- */
-
-static __attribute__((unused))
-int sys_select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds, struct timeval *timeout)
-{
-#if defined(__ARCH_WANT_SYS_OLD_SELECT) && !defined(__NR__newselect)
- struct sel_arg_struct {
- unsigned long n;
- fd_set *r, *w, *e;
- struct timeval *t;
- } arg = { .n = nfds, .r = rfds, .w = wfds, .e = efds, .t = timeout };
- return my_syscall1(__NR_select, &arg);
-#elif defined(__NR__newselect)
- return my_syscall5(__NR__newselect, nfds, rfds, wfds, efds, timeout);
-#elif defined(__NR_select)
- return my_syscall5(__NR_select, nfds, rfds, wfds, efds, timeout);
-#elif defined(__NR_pselect6)
- struct timespec t;
-
- if (timeout) {
- t.tv_sec = timeout->tv_sec;
- t.tv_nsec = timeout->tv_usec * 1000;
- }
- return my_syscall6(__NR_pselect6, nfds, rfds, wfds, efds, timeout ? &t : NULL, NULL);
-#elif defined(__NR_pselect6_time64)
- struct __kernel_timespec t;
-
- if (timeout) {
- t.tv_sec = timeout->tv_sec;
- t.tv_nsec = timeout->tv_usec * 1000;
- }
- return my_syscall6(__NR_pselect6_time64, nfds, rfds, wfds, efds, timeout ? &t : NULL, NULL);
-#else
- return __nolibc_enosys(__func__, nfds, rfds, wfds, efds, timeout);
-#endif
-}
-
-static __attribute__((unused))
-int select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds, struct timeval *timeout)
-{
- return __sysret(sys_select(nfds, rfds, wfds, efds, timeout));
-}
-
-
/*
* int setpgid(pid_t pid, pid_t pgid);
*/
diff --git a/tools/include/nolibc/sys/select.h b/tools/include/nolibc/sys/select.h
new file mode 100644
index 000000000000..74d0e55e3157
--- /dev/null
+++ b/tools/include/nolibc/sys/select.h
@@ -0,0 +1,109 @@
+/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
+
+/* make sure to include all global symbols */
+#include "../nolibc.h"
+
+#ifndef _NOLIBC_SYS_SELECT_H
+#define _NOLIBC_SYS_SELECT_H
+
+#include <linux/time.h>
+#include <linux/unistd.h>
+
+#include "../sys.h"
+
+/* commonly an fd_set represents 256 FDs */
+#ifndef FD_SETSIZE
+#define FD_SETSIZE 256
+#endif
+
+#define FD_SETIDXMASK (8 * sizeof(unsigned long))
+#define FD_SETBITMASK (8 * sizeof(unsigned long)-1)
+
+/* for select() */
+typedef struct {
+ unsigned long fds[(FD_SETSIZE + FD_SETBITMASK) / FD_SETIDXMASK];
+} fd_set;
+
+#define FD_CLR(fd, set) do { \
+ fd_set *__set = (set); \
+ int __fd = (fd); \
+ if (__fd >= 0) \
+ __set->fds[__fd / FD_SETIDXMASK] &= \
+ ~(1U << (__fd & FD_SETBITMASK)); \
+ } while (0)
+
+#define FD_SET(fd, set) do { \
+ fd_set *__set = (set); \
+ int __fd = (fd); \
+ if (__fd >= 0) \
+ __set->fds[__fd / FD_SETIDXMASK] |= \
+ 1 << (__fd & FD_SETBITMASK); \
+ } while (0)
+
+#define FD_ISSET(fd, set) ({ \
+ fd_set *__set = (set); \
+ int __fd = (fd); \
+ int __r = 0; \
+ if (__fd >= 0) \
+ __r = !!(__set->fds[__fd / FD_SETIDXMASK] & \
+1U << (__fd & FD_SETBITMASK)); \
+ __r; \
+ })
+
+#define FD_ZERO(set) do { \
+ fd_set *__set = (set); \
+ int __idx; \
+ int __size = (FD_SETSIZE+FD_SETBITMASK) / FD_SETIDXMASK;\
+ for (__idx = 0; __idx < __size; __idx++) \
+ __set->fds[__idx] = 0; \
+ } while (0)
+
+
+/*
+ * int select(int nfds, fd_set *read_fds, fd_set *write_fds,
+ * fd_set *except_fds, struct timeval *timeout);
+ */
+
+static __attribute__((unused))
+int sys_select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds, struct timeval *timeout)
+{
+#if defined(__ARCH_WANT_SYS_OLD_SELECT) && !defined(__NR__newselect)
+ struct sel_arg_struct {
+ unsigned long n;
+ fd_set *r, *w, *e;
+ struct timeval *t;
+ } arg = { .n = nfds, .r = rfds, .w = wfds, .e = efds, .t = timeout };
+ return my_syscall1(__NR_select, &arg);
+#elif defined(__NR__newselect)
+ return my_syscall5(__NR__newselect, nfds, rfds, wfds, efds, timeout);
+#elif defined(__NR_select)
+ return my_syscall5(__NR_select, nfds, rfds, wfds, efds, timeout);
+#elif defined(__NR_pselect6)
+ struct timespec t;
+
+ if (timeout) {
+ t.tv_sec = timeout->tv_sec;
+ t.tv_nsec = timeout->tv_usec * 1000;
+ }
+ return my_syscall6(__NR_pselect6, nfds, rfds, wfds, efds, timeout ? &t : NULL, NULL);
+#elif defined(__NR_pselect6_time64)
+ struct __kernel_timespec t;
+
+ if (timeout) {
+ t.tv_sec = timeout->tv_sec;
+ t.tv_nsec = timeout->tv_usec * 1000;
+ }
+ return my_syscall6(__NR_pselect6_time64, nfds, rfds, wfds, efds, timeout ? &t : NULL, NULL);
+#else
+ return __nolibc_enosys(__func__, nfds, rfds, wfds, efds, timeout);
+#endif
+}
+
+static __attribute__((unused))
+int select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds, struct timeval *timeout)
+{
+ return __sysret(sys_select(nfds, rfds, wfds, efds, timeout));
+}
+
+
+#endif /* _NOLIBC_SYS_SELECT_H */
diff --git a/tools/include/nolibc/types.h b/tools/include/nolibc/types.h
index 16c6e9ec9451..470a5f77bc0f 100644
--- a/tools/include/nolibc/types.h
+++ b/tools/include/nolibc/types.h
@@ -70,11 +70,6 @@
#define DT_LNK 0xa
#define DT_SOCK 0xc
-/* commonly an fd_set represents 256 FDs */
-#ifndef FD_SETSIZE
-#define FD_SETSIZE 256
-#endif
-
/* PATH_MAX and MAXPATHLEN are often used and found with plenty of different
* values.
*/
@@ -115,48 +110,6 @@
#define EXIT_SUCCESS 0
#define EXIT_FAILURE 1
-#define FD_SETIDXMASK (8 * sizeof(unsigned long))
-#define FD_SETBITMASK (8 * sizeof(unsigned long)-1)
-
-/* for select() */
-typedef struct {
- unsigned long fds[(FD_SETSIZE + FD_SETBITMASK) / FD_SETIDXMASK];
-} fd_set;
-
-#define FD_CLR(fd, set) do { \
- fd_set *__set = (set); \
- int __fd = (fd); \
- if (__fd >= 0) \
- __set->fds[__fd / FD_SETIDXMASK] &= \
- ~(1U << (__fd & FD_SETBITMASK)); \
- } while (0)
-
-#define FD_SET(fd, set) do { \
- fd_set *__set = (set); \
- int __fd = (fd); \
- if (__fd >= 0) \
- __set->fds[__fd / FD_SETIDXMASK] |= \
- 1 << (__fd & FD_SETBITMASK); \
- } while (0)
-
-#define FD_ISSET(fd, set) ({ \
- fd_set *__set = (set); \
- int __fd = (fd); \
- int __r = 0; \
- if (__fd >= 0) \
- __r = !!(__set->fds[__fd / FD_SETIDXMASK] & \
-1U << (__fd & FD_SETBITMASK)); \
- __r; \
- })
-
-#define FD_ZERO(set) do { \
- fd_set *__set = (set); \
- int __idx; \
- int __size = (FD_SETSIZE+FD_SETBITMASK) / FD_SETIDXMASK;\
- for (__idx = 0; __idx < __size; __idx++) \
- __set->fds[__idx] = 0; \
- } while (0)
-
/* for getdents64() */
struct linux_dirent64 {
uint64_t d_ino;
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