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-rw-r--r--libblkid/lib/cpuset.c403
1 files changed, 403 insertions, 0 deletions
diff --git a/libblkid/lib/cpuset.c b/libblkid/lib/cpuset.c
new file mode 100644
index 000000000..d715720e3
--- /dev/null
+++ b/libblkid/lib/cpuset.c
@@ -0,0 +1,403 @@
+/*
+ * Terminology:
+ *
+ * cpuset - (libc) cpu_set_t data structure represents set of CPUs
+ * cpumask - string with hex mask (e.g. "0x00000001")
+ * cpulist - string with CPU ranges (e.g. "0-3,5,7,8")
+ *
+ * Based on code from taskset.c and Linux kernel.
+ *
+ * This file may be redistributed under the terms of the
+ * GNU Lesser General Public License.
+ *
+ * Copyright (C) 2010 Karel Zak <kzak@redhat.com>
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sched.h>
+#include <errno.h>
+#include <string.h>
+#include <ctype.h>
+#include <sys/syscall.h>
+
+#include "cpuset.h"
+#include "c.h"
+
+static inline int val_to_char(int v)
+{
+ if (v >= 0 && v < 10)
+ return '0' + v;
+ else if (v >= 10 && v < 16)
+ return ('a' - 10) + v;
+ else
+ return -1;
+}
+
+static inline int char_to_val(int c)
+{
+ int cl;
+
+ cl = tolower(c);
+ if (c >= '0' && c <= '9')
+ return c - '0';
+ else if (cl >= 'a' && cl <= 'f')
+ return cl + (10 - 'a');
+ else
+ return -1;
+}
+
+static const char *nexttoken(const char *q, int sep)
+{
+ if (q)
+ q = strchr(q, sep);
+ if (q)
+ q++;
+ return q;
+}
+
+/*
+ * Number of bits in a CPU bitmask on current system
+ */
+int get_max_number_of_cpus(void)
+{
+#ifdef SYS_sched_getaffinity
+ int n, cpus = 2048;
+ size_t setsize;
+ cpu_set_t *set = cpuset_alloc(cpus, &setsize, NULL);
+
+ if (!set)
+ return -1; /* error */
+
+ for (;;) {
+ CPU_ZERO_S(setsize, set);
+
+ /* the library version does not return size of cpumask_t */
+ n = syscall(SYS_sched_getaffinity, 0, setsize, set);
+
+ if (n < 0 && errno == EINVAL && cpus < 1024 * 1024) {
+ cpuset_free(set);
+ cpus *= 2;
+ set = cpuset_alloc(cpus, &setsize, NULL);
+ if (!set)
+ return -1; /* error */
+ continue;
+ }
+ cpuset_free(set);
+ return n * 8;
+ }
+#endif
+ return -1;
+}
+
+/*
+ * Allocates a new set for ncpus and returns size in bytes and size in bits
+ */
+cpu_set_t *cpuset_alloc(int ncpus, size_t *setsize, size_t *nbits)
+{
+ cpu_set_t *set = CPU_ALLOC(ncpus);
+
+ if (!set)
+ return NULL;
+ if (setsize)
+ *setsize = CPU_ALLOC_SIZE(ncpus);
+ if (nbits)
+ *nbits = cpuset_nbits(CPU_ALLOC_SIZE(ncpus));
+ return set;
+}
+
+void cpuset_free(cpu_set_t *set)
+{
+ CPU_FREE(set);
+}
+
+#if !HAVE_DECL_CPU_ALLOC
+/* Please, use CPU_COUNT_S() macro. This is fallback */
+int __cpuset_count_s(size_t setsize, const cpu_set_t *set)
+{
+ int s = 0;
+ const __cpu_mask *p = set->__bits;
+ const __cpu_mask *end = &set->__bits[setsize / sizeof (__cpu_mask)];
+
+ while (p < end) {
+ __cpu_mask l = *p++;
+
+ if (l == 0)
+ continue;
+# if LONG_BIT > 32
+ l = (l & 0x5555555555555555ul) + ((l >> 1) & 0x5555555555555555ul);
+ l = (l & 0x3333333333333333ul) + ((l >> 2) & 0x3333333333333333ul);
+ l = (l & 0x0f0f0f0f0f0f0f0ful) + ((l >> 4) & 0x0f0f0f0f0f0f0f0ful);
+ l = (l & 0x00ff00ff00ff00fful) + ((l >> 8) & 0x00ff00ff00ff00fful);
+ l = (l & 0x0000ffff0000fffful) + ((l >> 16) & 0x0000ffff0000fffful);
+ l = (l & 0x00000000fffffffful) + ((l >> 32) & 0x00000000fffffffful);
+# else
+ l = (l & 0x55555555ul) + ((l >> 1) & 0x55555555ul);
+ l = (l & 0x33333333ul) + ((l >> 2) & 0x33333333ul);
+ l = (l & 0x0f0f0f0ful) + ((l >> 4) & 0x0f0f0f0ful);
+ l = (l & 0x00ff00fful) + ((l >> 8) & 0x00ff00fful);
+ l = (l & 0x0000fffful) + ((l >> 16) & 0x0000fffful);
+# endif
+ s += l;
+ }
+ return s;
+}
+#endif
+
+/*
+ * Returns human readable representation of the cpuset. The output format is
+ * a list of CPUs with ranges (for example, "0,1,3-9").
+ */
+char *cpulist_create(char *str, size_t len,
+ cpu_set_t *set, size_t setsize)
+{
+ size_t i;
+ char *ptr = str;
+ int entry_made = 0;
+ size_t max = cpuset_nbits(setsize);
+
+ for (i = 0; i < max; i++) {
+ if (CPU_ISSET_S(i, setsize, set)) {
+ int rlen;
+ size_t j, run = 0;
+ entry_made = 1;
+ for (j = i + 1; j < max; j++) {
+ if (CPU_ISSET_S(j, setsize, set))
+ run++;
+ else
+ break;
+ }
+ if (!run)
+ rlen = snprintf(ptr, len, "%zd,", i);
+ else if (run == 1) {
+ rlen = snprintf(ptr, len, "%zd,%zd,", i, i + 1);
+ i++;
+ } else {
+ rlen = snprintf(ptr, len, "%zd-%zd,", i, i + run);
+ i += run;
+ }
+ if (rlen < 0 || (size_t) rlen + 1 > len)
+ return NULL;
+ ptr += rlen;
+ if (rlen > 0 && len > (size_t) rlen)
+ len -= rlen;
+ else
+ len = 0;
+ }
+ }
+ ptr -= entry_made;
+ *ptr = '\0';
+
+ return str;
+}
+
+/*
+ * Returns string with CPU mask.
+ */
+char *cpumask_create(char *str, size_t len,
+ cpu_set_t *set, size_t setsize)
+{
+ char *ptr = str;
+ char *ret = NULL;
+ int cpu;
+
+ for (cpu = cpuset_nbits(setsize) - 4; cpu >= 0; cpu -= 4) {
+ char val = 0;
+
+ if (len == (size_t) (ptr - str))
+ break;
+
+ if (CPU_ISSET_S(cpu, setsize, set))
+ val |= 1;
+ if (CPU_ISSET_S(cpu + 1, setsize, set))
+ val |= 2;
+ if (CPU_ISSET_S(cpu + 2, setsize, set))
+ val |= 4;
+ if (CPU_ISSET_S(cpu + 3, setsize, set))
+ val |= 8;
+
+ if (!ret && val)
+ ret = ptr;
+ *ptr++ = val_to_char(val);
+ }
+ *ptr = '\0';
+ return ret ? ret : ptr - 1;
+}
+
+/*
+ * Parses string with CPUs mask.
+ */
+int cpumask_parse(const char *str, cpu_set_t *set, size_t setsize)
+{
+ int len = strlen(str);
+ const char *ptr = str + len - 1;
+ int cpu = 0;
+
+ /* skip 0x, it's all hex anyway */
+ if (len > 1 && !memcmp(str, "0x", 2L))
+ str += 2;
+
+ CPU_ZERO_S(setsize, set);
+
+ while (ptr >= str) {
+ char val;
+
+ /* cpu masks in /sys uses comma as a separator */
+ if (*ptr == ',')
+ ptr--;
+
+ val = char_to_val(*ptr);
+ if (val == (char) -1)
+ return -1;
+ if (val & 1)
+ CPU_SET_S(cpu, setsize, set);
+ if (val & 2)
+ CPU_SET_S(cpu + 1, setsize, set);
+ if (val & 4)
+ CPU_SET_S(cpu + 2, setsize, set);
+ if (val & 8)
+ CPU_SET_S(cpu + 3, setsize, set);
+ len--;
+ ptr--;
+ cpu += 4;
+ }
+
+ return 0;
+}
+
+/*
+ * Parses string with list of CPU ranges.
+ * Returns 0 on success.
+ * Returns 1 on error.
+ * Returns 2 if fail is set and a cpu number passed in the list doesn't fit
+ * into the cpu_set. If fail is not set cpu numbers that do not fit are
+ * ignored and 0 is returned instead.
+ */
+int cpulist_parse(const char *str, cpu_set_t *set, size_t setsize, int fail)
+{
+ size_t max = cpuset_nbits(setsize);
+ const char *p, *q;
+ int r = 0;
+
+ q = str;
+ CPU_ZERO_S(setsize, set);
+
+ while (p = q, q = nexttoken(q, ','), p) {
+ unsigned int a; /* beginning of range */
+ unsigned int b; /* end of range */
+ unsigned int s; /* stride */
+ const char *c1, *c2;
+ char c;
+
+ if ((r = sscanf(p, "%u%c", &a, &c)) < 1)
+ return 1;
+ b = a;
+ s = 1;
+
+ c1 = nexttoken(p, '-');
+ c2 = nexttoken(p, ',');
+ if (c1 != NULL && (c2 == NULL || c1 < c2)) {
+ if ((r = sscanf(c1, "%u%c", &b, &c)) < 1)
+ return 1;
+ c1 = nexttoken(c1, ':');
+ if (c1 != NULL && (c2 == NULL || c1 < c2)) {
+ if ((r = sscanf(c1, "%u%c", &s, &c)) < 1)
+ return 1;
+ if (s == 0)
+ return 1;
+ }
+ }
+
+ if (!(a <= b))
+ return 1;
+ while (a <= b) {
+ if (fail && (a >= max))
+ return 2;
+ CPU_SET_S(a, setsize, set);
+ a += s;
+ }
+ }
+
+ if (r == 2)
+ return 1;
+ return 0;
+}
+
+#ifdef TEST_PROGRAM
+
+#include <getopt.h>
+
+int main(int argc, char *argv[])
+{
+ cpu_set_t *set;
+ size_t setsize, buflen, nbits;
+ char *buf, *mask = NULL, *range = NULL;
+ int ncpus = 2048, rc, c;
+
+ static const struct option longopts[] = {
+ { "ncpus", 1, 0, 'n' },
+ { "mask", 1, 0, 'm' },
+ { "range", 1, 0, 'r' },
+ { NULL, 0, 0, 0 }
+ };
+
+ while ((c = getopt_long(argc, argv, "n:m:r:", longopts, NULL)) != -1) {
+ switch(c) {
+ case 'n':
+ ncpus = atoi(optarg);
+ break;
+ case 'm':
+ mask = strdup(optarg);
+ break;
+ case 'r':
+ range = strdup(optarg);
+ break;
+ default:
+ goto usage_err;
+ }
+ }
+
+ if (!mask && !range)
+ goto usage_err;
+
+ set = cpuset_alloc(ncpus, &setsize, &nbits);
+ if (!set)
+ err(EXIT_FAILURE, "failed to allocate cpu set");
+
+ /*
+ fprintf(stderr, "ncpus: %d, cpuset bits: %zd, cpuset bytes: %zd\n",
+ ncpus, nbits, setsize);
+ */
+
+ buflen = 7 * nbits;
+ buf = malloc(buflen);
+ if (!buf)
+ err(EXIT_FAILURE, "failed to allocate cpu set buffer");
+
+ if (mask)
+ rc = cpumask_parse(mask, set, setsize);
+ else
+ rc = cpulist_parse(range, set, setsize, 0);
+
+ if (rc)
+ errx(EXIT_FAILURE, "failed to parse string: %s", mask ? : range);
+
+ printf("%-15s = %15s ", mask ? : range,
+ cpumask_create(buf, buflen, set, setsize));
+ printf("[%s]\n", cpulist_create(buf, buflen, set, setsize));
+
+ free(buf);
+ free(mask);
+ free(range);
+ cpuset_free(set);
+
+ return EXIT_SUCCESS;
+
+usage_err:
+ fprintf(stderr,
+ "usage: %s [--ncpus <num>] --mask <mask> | --range <list>",
+ program_invocation_short_name);
+ exit(EXIT_FAILURE);
+}
+#endif
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