musl "implements" several sched_xxx() functions by returning ENOSYS. As an alternative, either pthread_(g|s)etschedparam() or direct syscalls can be used.
References: https://git.kernel.org/pub/scm/utils/util-linux/util-linux.git/commit/schedutils/chrt.c?id=fcc3078754291d2f5121797eb91b364f8e24b2f1 References: http://git.musl-libc.org/cgit/musl/commit/src/sched/sched_setscheduler.c?id=1e21e78bf7a5c24c217446d8760be7b7188711c2 Signed-off-by: Christian Eggers <cegg...@arri.de> --- util-linux/chrt.c | 31 +++++++++++++++++++++++++++++-- 1 file changed, 29 insertions(+), 2 deletions(-) diff --git a/util-linux/chrt.c b/util-linux/chrt.c index 4dd78dabf..e465d7cec 100644 --- a/util-linux/chrt.c +++ b/util-linux/chrt.c @@ -34,6 +34,9 @@ //usage: "You need CAP_SYS_NICE privileges to set scheduling attributes of a process" #include <sched.h> +#if defined (__linux__) +# include <sys/syscall.h> +#endif #include "libbb.h" #ifndef SCHED_IDLE # define SCHED_IDLE 5 @@ -85,6 +88,7 @@ int chrt_main(int argc UNUSED_PARAM, char **argv) char *priority = priority; /* for compiler */ const char *current_new; int policy = SCHED_RR; + int ret; opt = getopt32(argv, "^" "+" "mprfobi" @@ -132,7 +136,15 @@ int chrt_main(int argc UNUSED_PARAM, char **argv) if (opt & OPT_p) { int pol; print_rt_info: +#if defined (__linux__) && defined(SYS_sched_getscheduler) + /* musl libc returns ENOSYS for its sched_getscheduler library + * function, because the sched_getscheduler Linux kernel system call + * does not conform to Posix; so we use the system call directly + */ + pol = syscall(SYS_sched_getscheduler, pid); +#else pol = sched_getscheduler(pid); +#endif if (pol < 0) bb_perror_msg_and_die("can't %cet pid %u's policy", 'g', (int)pid); #ifdef SCHED_RESET_ON_FORK @@ -149,7 +161,12 @@ int chrt_main(int argc UNUSED_PARAM, char **argv) printf("pid %u's %s scheduling policy: SCHED_%s\n", pid, current_new, policy_name(pol) ); - if (sched_getparam(pid, &sp)) +#if defined (__linux__) && defined(SYS_sched_getparam) + ret = syscall(SYS_sched_getparam, pid, &sp); +#else + ret = sched_getparam(pid, &sp); +#endif + if (ret) bb_perror_msg_and_die("can't get pid %u's attributes", (int)pid); printf("pid %u's %s scheduling priority: %d\n", (int)pid, current_new, sp.sched_priority @@ -168,7 +185,17 @@ int chrt_main(int argc UNUSED_PARAM, char **argv) sched_get_priority_min(policy), sched_get_priority_max(policy) ); - if (sched_setscheduler(pid, policy, &sp) < 0) +#if defined (__linux__) && defined(SYS_sched_setscheduler) + /* musl libc returns ENOSYS for its sched_setscheduler library + * function, because the sched_setscheduler Linux kernel system call + * does not conform to Posix; so we use the system call directly + */ + ret = syscall(SYS_sched_setscheduler, pid, policy, &sp); +#else + ret = sched_setscheduler(pid, policy, &sp); +#endif + + if (ret < 0) bb_perror_msg_and_die("can't %cet pid %u's policy", 's', (int)pid); if (!argv[0]) /* "-p PRIO PID [...]" */ -- Christian Eggers Embedded software developer Arnold & Richter Cine Technik GmbH & Co. Betriebs KG Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer: HRA 57918 Persoenlich haftender Gesellschafter: Arnold & Richter Cine Technik GmbH Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer: HRB 54477 Geschaeftsfuehrer: Dr. Michael Neuhaeuser; Stephan Schenk; Walter Trauninger; Markus Zeiler _______________________________________________ busybox mailing list busybox@busybox.net http://lists.busybox.net/mailman/listinfo/busybox