- add applet taskset to set/retrieve the CPU affinity of a process

   text    data     bss     dec     hex filename
    584       0       0     584     248 taskset.o.gcc-2.95
    509       0       0     509     1fd taskset.o.gcc-3.3
    505       0       0     505     1f9 taskset.o.gcc-3.4
    506       0       0     506     1fa taskset.o.gcc-4.0
    498       0       0     498     1f2 taskset.o.gcc-4.1
    495       0       0     495     1ef taskset.o.gcc-4.2-HEAD

3 files changed, 74 insertions, 0 deletions

diff --git a/miscutils/Config.in b/miscutils/Config.in
index fc90b54..37c1de8 100644
--- a/miscutils/Config.in
+++ b/miscutils/Config.in
@@ -291,6 +291,12 @@ config CONFIG_SETSID
 	help
 	  setsid runs a program in a new session
 
+config CONFIG_TASKSET
+	bool "taskset"
+	default n
+	help
+	  Retrieve or set a processes's CPU affinity (on linux)
+
 config CONFIG_TIME
 	bool "time"
 	default n
diff --git a/miscutils/Makefile.in b/miscutils/Makefile.in
index a0b6b72..d60d687 100644
--- a/miscutils/Makefile.in
+++ b/miscutils/Makefile.in
@@ -28,6 +28,7 @@ MISCUTILS-$(CONFIG_RUNLEVEL)    += runlevel.o
 MISCUTILS-$(CONFIG_RX)          += rx.o
 MISCUTILS-$(CONFIG_SETSID)      += setsid.o
 MISCUTILS-$(CONFIG_STRINGS)     += strings.o
+MISCUTILS-$(CONFIG_TASKSET)     += taskset.o
 MISCUTILS-$(CONFIG_TIME)        += time.o
 MISCUTILS-$(CONFIG_WATCHDOG)    += watchdog.o
 
diff --git a/miscutils/taskset.c b/miscutils/taskset.c
new file mode 100644
index 0000000..a72f3ff
--- /dev/null
+++ b/miscutils/taskset.c
@@ -0,0 +1,67 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * taskset - retrieve or set a processes's CPU affinity
+ * Copyright (c) 2006 Bernhard Fischer
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ */
+
+#include "busybox.h"
+#include <sched.h>
+#include <unistd.h>
+#include <getopt.h> /* optind */
+
+int taskset_main(int argc, char** argv)
+{
+	cpu_set_t mask, new_mask;
+	pid_t pid = 0;
+	unsigned long ul;
+	const char *state = "current\0new";
+	char *p_opt = NULL, *aff = NULL;
+
+	ul = bb_getopt_ulflags(argc, argv, "+p:", &p_opt);
+#define TASKSET_OPT_p (1)
+
+	if (ul & TASKSET_OPT_p) {
+		if (argc == optind+1) { /* -p <aff> <pid> */
+			aff = p_opt;
+			p_opt = argv[optind];
+		}
+		argv += optind; /* me -p <arg> */
+		pid = bb_xgetularg10_bnd(p_opt, 1, ULONG_MAX); /* -p <pid> */
+	} else
+		aff = *++argv; /* <aff> <cmd...> */
+	if (aff) {
+/*		to_cpuset(bb_xgetularg_bnd(aff, 16, 1, ULONG_MAX), &new_mask); */
+		unsigned i = 0;
+		unsigned long l = bb_xgetularg_bnd(aff, 16, 1, ULONG_MAX);
+
+		CPU_ZERO(&new_mask);
+		while (i < CPU_SETSIZE && l >= (1<<i)) {
+			if ((1<<i) & l)
+				CPU_SET(i, &new_mask);
+			++i;
+		}
+	}
+
+	if (ul & TASKSET_OPT_p) {
+print_aff:
+		if (sched_getaffinity(pid, sizeof (mask), &mask) < 0)
+			bb_perror_msg_and_die("Failed to %cet pid %d's affinity", 'g', pid);
+		bb_printf("pid %d's %s affinity mask: %x\n", /* %x .. perhaps _FANCY */
+				pid, state, mask);
+		if (!*argv) /* no new affinity given or we did print already, done. */
+			return EXIT_SUCCESS;
+	}
+
+	if (sched_setaffinity(pid, sizeof (new_mask), &new_mask))
+		bb_perror_msg_and_die("Failed to %cet pid %d's affinity", 's', pid);
+	if (ul & TASKSET_OPT_p) {
+		state += 8;
+		++argv;
+		goto print_aff;
+	}
+	++argv;
+	execvp(*argv, argv);
+	bb_perror_msg_and_die("%s", *argv);
+}