1 files changed, 221 insertions, 0 deletions
diff --git a/util-linux/taskset.c b/util-linux/taskset.c
new file mode 100644
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--- /dev/null
+++ b/util-linux/taskset.c
@@ -0,0 +1,221 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * taskset - retrieve or set a processes' CPU affinity
+ * Copyright (c) 2006 Bernhard Reutner-Fischer
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
+ */
+
+//config:config TASKSET
+//config:	bool "taskset"
+//config:	default y
+//config:	help
+//config:	  Retrieve or set a processes's CPU affinity.
+//config:	  This requires sched_{g,s}etaffinity support in your libc.
+//config:
+//config:config FEATURE_TASKSET_FANCY
+//config:	bool "Fancy output"
+//config:	default y
+//config:	depends on TASKSET
+//config:	help
+//config:	  Needed for machines with more than 32-64 CPUs:
+//config:	  affinity parameter 0xHHHHHHHHHHHHHHHHHHHH can be arbitrarily long
+//config:	  in this case. Otherwise, it is limited to sizeof(long).
+
+//applet:IF_TASKSET(APPLET(taskset, BB_DIR_USR_BIN, BB_SUID_DROP))
+//kbuild:lib-$(CONFIG_TASKSET) += taskset.o
+
+//usage:#define taskset_trivial_usage
+//usage:       "[-p] [HEXMASK] PID | PROG ARGS"
+//usage:#define taskset_full_usage "\n\n"
+//usage:       "Set or get CPU affinity\n"
+//usage:     "\n	-p	Operate on an existing PID"
+//usage:
+//usage:#define taskset_example_usage
+//usage:       "$ taskset 0x7 ./dgemm_test&\n"
+//usage:       "$ taskset -p 0x1 $!\n"
+//usage:       "pid 4790's current affinity mask: 7\n"
+//usage:       "pid 4790's new affinity mask: 1\n"
+//usage:       "$ taskset 0x7 /bin/sh -c './taskset -p 0x1 $$'\n"
+//usage:       "pid 6671's current affinity mask: 1\n"
+//usage:       "pid 6671's new affinity mask: 1\n"
+//usage:       "$ taskset -p 1\n"
+//usage:       "pid 1's current affinity mask: 3\n"
+/*
+ * Not yet implemented:
+ * -a/--all-tasks (affect all threads)
+ *	needs to get TIDs from /proc/PID/task/ and use _them_ as "pid" in sched_setaffinity(pid)
+ * -c/--cpu-list  (specify CPUs via "1,3,5-7")
+ */
+
+#include <sched.h>
+#include "libbb.h"
+
+typedef unsigned long ul;
+#define SZOF_UL (unsigned)(sizeof(ul))
+#define BITS_UL (unsigned)(sizeof(ul)*8)
+#define MASK_UL (unsigned)(sizeof(ul)*8 - 1)
+
+#if ENABLE_FEATURE_TASKSET_FANCY
+#define TASKSET_PRINTF_MASK "%s"
+/* craft a string from the mask */
+static char *from_mask(const ul *mask, unsigned sz_in_bytes)
+{
+	char *str = xzalloc((sz_in_bytes+1) * 2); /* we will leak it */
+	char *p = str;
+	for (;;) {
+		ul v = *mask++;
+		if (SZOF_UL == 4)
+			p += sprintf(p, "%08lx", v);
+		if (SZOF_UL == 8)
+			p += sprintf(p, "%016lx", v);
+		if (SZOF_UL == 16)
+			p += sprintf(p, "%032lx", v); /* :) */
+		sz_in_bytes -= SZOF_UL;
+		if ((int)sz_in_bytes <= 0)
+			break;
+	}
+	while (str[0] == '0' && str[1])
+		str++;
+	return str;
+}
+#else
+#define TASKSET_PRINTF_MASK "%lx"
+static unsigned long long from_mask(ul *mask, unsigned sz_in_bytes UNUSED_PARAM)
+{
+	return *mask;
+}
+#endif
+
+static unsigned long *get_aff(int pid, unsigned *sz)
+{
+	int r;
+	unsigned long *mask = NULL;
+	unsigned sz_in_bytes = *sz;
+
+	for (;;) {
+		mask = xrealloc(mask, sz_in_bytes);
+		r = sched_getaffinity(pid, sz_in_bytes, (void*)mask);
+		if (r == 0)
+			break;
+		sz_in_bytes *= 2;
+		if (errno == EINVAL && (int)sz_in_bytes > 0)
+			continue;
+		bb_perror_msg_and_die("can't %cet pid %d's affinity", 'g', pid);
+	}
+	//bb_error_msg("get mask[0]:%lx sz_in_bytes:%d", mask[0], sz_in_bytes);
+	*sz = sz_in_bytes;
+	return mask;
+}
+
+int taskset_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int taskset_main(int argc UNUSED_PARAM, char **argv)
+{
+	ul *mask;
+	unsigned mask_size_in_bytes;
+	pid_t pid = 0;
+	unsigned opt_p;
+	const char *current_new;
+	char *aff;
+
+	/* NB: we mimic util-linux's taskset: -p does not take
+	 * an argument, i.e., "-pN" is NOT valid, only "-p N"!
+	 * Indeed, util-linux-2.13-pre7 uses:
+	 * getopt_long(argc, argv, "+pchV", ...), not "...p:..." */
+
+	opt_complementary = "-1"; /* at least 1 arg */
+	opt_p = getopt32(argv, "+p");
+	argv += optind;
+
+	aff = *argv++;
+	if (opt_p) {
+		char *pid_str = aff;
+		if (*argv) { /* "-p <aff> <pid> ...rest.is.ignored..." */
+			pid_str = *argv; /* NB: *argv != NULL in this case */
+		}
+		/* else it was just "-p <pid>", and *argv == NULL */
+		pid = xatoul_range(pid_str, 1, ((unsigned)(pid_t)ULONG_MAX) >> 1);
+	} else {
+		/* <aff> <cmd...> */
+		if (!*argv)
+			bb_show_usage();
+	}
+
+	mask_size_in_bytes = SZOF_UL;
+	current_new = "current";
+ print_aff:
+	mask = get_aff(pid, &mask_size_in_bytes);
+	if (opt_p) {
+		printf("pid %d's %s affinity mask: "TASKSET_PRINTF_MASK"\n",
+				pid, current_new, from_mask(mask, mask_size_in_bytes));
+		if (*argv == NULL) {
+			/* Either it was just "-p <pid>",
+			 * or it was "-p <aff> <pid>" and we came here
+			 * for the second time (see goto below) */
+			return EXIT_SUCCESS;
+		}
+		*argv = NULL;
+		current_new = "new";
+	}
+	memset(mask, 0, mask_size_in_bytes);
+
+	/* Affinity was specified, translate it into mask */
+	/* it is always in hex, skip "0x" if it exists */
+	if (aff[0] == '0' && (aff[1]|0x20) == 'x')
+		aff += 2;
+
+	if (!ENABLE_FEATURE_TASKSET_FANCY) {
+		mask[0] = xstrtoul(aff, 16);
+	} else {
+		unsigned i;
+		char *last_char;
+
+		i = 0; /* bit pos in mask[] */
+
+		/* aff is ASCII hex string, accept very long masks in this form.
+		 * Process hex string AABBCCDD... to ulong mask[]
+		 * from the rightmost nibble, which is least-significant.
+		 * Bits not fitting into mask[] are ignored: (example: 1234
+		 * in 12340000000000000000000000000000000000000ff)
+		 */
+		last_char = strchrnul(aff, '\0');
+		while (last_char > aff) {
+			char c;
+			ul val;
+
+			last_char--;
+			c = *last_char;
+			if (isdigit(c))
+				val = c - '0';
+			else if ((c|0x20) >= 'a' && (c|0x20) <= 'f')
+				val = (c|0x20) - ('a' - 10);
+			else
+				bb_error_msg_and_die("bad affinity '%s'", aff);
+
+			if (i < mask_size_in_bytes * 8) {
+				mask[i / BITS_UL] |= val << (i & MASK_UL);
+				//bb_error_msg("bit %d set", i);
+			}
+			/* else:
+			 * We can error out here, but we don't.
+			 * For one, kernel itself ignores bits in mask[]
+			 * which do not map to any CPUs:
+			 * if mask[] has one 32-bit long element,
+			 * but you have only 8 CPUs, all bits beyond first 8
+			 * are ignored, silently.
+			 * No point in making bits past 31th to be errors.
+			 */
+			i += 4;
+		}
+	}
+
+	/* Set pid's or our own (pid==0) affinity */
+	if (sched_setaffinity(pid, mask_size_in_bytes, (void*)mask))
+		bb_perror_msg_and_die("can't %cet pid %d's affinity", 's', pid);
+	//bb_error_msg("set mask[0]:%lx", mask[0]);
+
+	if (!argv[0]) /* "-p <aff> <pid> [...ignored...]" */
+		goto print_aff; /* print new affinity and exit */
+
+	BB_EXECVP_or_die(argv);
+}