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| author | Christian Eggers <ceggers@arri.de> | 2020-11-15 20:25:09 +0100 |
|---|---|---|
| committer | Denys Vlasenko <vda.linux@googlemail.com> | 2020-11-15 20:26:46 +0100 |
| commit | 89f063b900edf8b38c9dc05953887cf09b121378 (patch) | |
| tree | cac0a171637204bafcb92939de84c94221b2fd51 | |
| parent | 64981b4c8e88812c322bee3832f1d421ff670ed5 (diff) | |
| download | busybox-89f063b900edf8b38c9dc05953887cf09b121378.tar.gz | |
chrt: support for musl C library
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 <ceggers@arri.de>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
| -rw-r--r-- | util-linux/chrt.c | 34 |
1 files changed, 32 insertions, 2 deletions
diff --git a/util-linux/chrt.c b/util-linux/chrt.c index 4dd78dabf..6e8f66741 100644 --- a/util-linux/chrt.c +++ b/util-linux/chrt.c @@ -39,6 +39,17 @@ # define SCHED_IDLE 5 #endif +//musl has no __MUSL__ or similar define to check for, +//but its <sys/types.h> has these lines: +// #define __NEED_fsblkcnt_t +// #define __NEED_fsfilcnt_t +#if defined(__linux__) && defined(__NEED_fsblkcnt_t) && defined(__NEED_fsfilcnt_t) +# define LIBC_IS_MUSL 1 +# include <sys/syscall.h> +#else +# define LIBC_IS_MUSL 0 +#endif + static const char *policy_name(int pol) { if (pol > 6) @@ -85,6 +96,7 @@ 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 +144,15 @@ int chrt_main(int argc UNUSED_PARAM, char **argv) if (opt & OPT_p) { int pol; print_rt_info: +#if LIBC_IS_MUSL + /* 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 +169,12 @@ 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 LIBC_IS_MUSL + 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 +193,12 @@ 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 LIBC_IS_MUSL + ret = syscall(SYS_sched_setscheduler, pid, policy, &sp); +#else + ret = sched_setscheduler(pid, policy, &sp); +#endif + if (ret) bb_perror_msg_and_die("can't %cet pid %u's policy", 's', (int)pid); if (!argv[0]) /* "-p PRIO PID [...]" */ |