[PATCH 3/3] trace-cmd record: add --cpu-list option

[Luiz Capitulino <lcapitulino@redhat.com>]

With --cpu-list you can do:

  # trace-cmd record --cpu-list 1,4,10-15 [...]

Which is much more human friendly than -M.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
---
 Documentation/trace-cmd-record.1.txt |   4 +
 trace-record.c                       | 138 +++++++++++++++++++++++++++++++++++
 2 files changed, 142 insertions(+)

diff --git a/Documentation/trace-cmd-record.1.txt b/Documentation/trace-cmd-record.1.txt
index b80520e..d7e806a 100644
--- a/Documentation/trace-cmd-record.1.txt
+++ b/Documentation/trace-cmd-record.1.txt
@@ -304,6 +304,10 @@ OPTIONS
     executed will not be changed. This is useful if you want to monitor the
     output of the command being executed, but not see the output from trace-cmd.
 
+*--cpu-list list*::
+    List of CPUs to be traced. The "list" argument can be comma separated
+    (eg. 1,2,4,5), a range (eg. 1-10) or a mix of the two (eg. 1,2,10-15).
+
 EXAMPLES
 --------
 
diff --git a/trace-record.c b/trace-record.c
index b042993..4452979 100644
--- a/trace-record.c
+++ b/trace-record.c
@@ -23,6 +23,7 @@
 #include <string.h>
 #include <stdarg.h>
 #include <getopt.h>
+#include <limits.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/time.h>
@@ -47,6 +48,7 @@
 
 #include "trace-local.h"
 #include "trace-msg.h"
+#include "cpu.h"
 
 #define _STR(x) #x
 #define STR(x) _STR(x)
@@ -179,6 +181,118 @@ static struct tracecmd_recorder *recorder;
 
 static int ignore_event_not_found = 0;
 
+static int read_cpu_nr(const char *str, int *ret)
+{
+	char *endptr;
+	int val;
+
+	errno = 0;
+	val = strtol(str, &endptr, 10);
+
+	if ((errno == ERANGE && (val == LONG_MAX || val == LONG_MIN))
+			|| (errno != 0 && val == 0))
+				return -1;
+
+	if (endptr == str)
+		return -1;
+
+	if (*endptr != '\0')
+		return -1;
+
+	*ret = val;
+	return 0;
+}
+
+static int set_single_cpu(const char *str, uint64_t *ret_mask)
+{
+	int cpu, err;
+
+	err = read_cpu_nr(str, &cpu);
+	if (err || cpu < 0)
+		return -1;
+
+	cpu_set(ret_mask, cpu);
+	return 0;
+}
+
+static int parse_one(char *str, char **saveptr)
+{
+	int err, cpu;
+	char *p;
+
+	p = strtok_r(str, "-", saveptr);
+	if (!p)
+		return -1;
+
+	err = read_cpu_nr(p, &cpu);
+	if (err)
+		return -1;
+
+	return cpu;
+}
+
+static int set_range_cpu(const char *str, uint64_t *ret_mask)
+{
+	int i, begin, end, err = -1;
+	char *saveptr, *range;
+
+	range = strdup(str);
+	if (!range)
+		return -1;
+
+	begin = parse_one(range, &saveptr);
+	if (begin < 0)
+		goto out;
+
+	end = parse_one(NULL, &saveptr);
+	if (begin < 0)
+		goto out;
+
+	if (begin > end)
+		goto out;
+
+	for (i = begin; i <= end; i++)
+		cpu_set(ret_mask, i);
+
+	err = 0;
+
+out:
+	free(range);
+	return err;
+}
+
+static int has_range(const char *str)
+{
+	return strchr(str, '-') != NULL;
+}
+
+static int parse_cpumask_str(const char *cpumask_str, uint64_t *ret_mask)
+{
+	char *saveptr, *str, *p;
+	int err = 0;
+
+	str = strdup(cpumask_str);
+	if (!str)
+		return -1;
+
+	*ret_mask = 0;
+
+	p = strtok_r(str, ",", &saveptr);
+	while (p) {
+		if (has_range(p))
+			err = set_range_cpu(p, ret_mask);
+		else
+			err = set_single_cpu(p, ret_mask);
+		if (err)
+			goto out;
+		p = strtok_r(NULL, ",", &saveptr);
+	}
+
+out:
+	free(str);
+	return err;
+}
+
 static inline int is_top_instance(struct buffer_instance *instance)
 {
 	return instance == &top_instance;
@@ -2114,6 +2228,25 @@ static char *alloc_mask_from_hex(const char *str)
 	return cpumask;
 }
 
+static char *alloc_mask_from_list(const char *cpu_list)
+{
+	char *cpumask_str;
+	uint64_t cpumask;
+	int ret;
+
+	ret = parse_cpumask_str(cpu_list, &cpumask);
+	if (ret < 0)
+		die("can't parse cpumask");
+
+	cpumask_str = malloc(MASK_STR_MAX);
+	if (!cpumask_str)
+		die("can't allocate cpumask");
+
+	snprintf(cpumask_str, MASK_STR_MAX-1, "%lx", cpumask);
+	return cpumask_str;
+}
+
+
 static void set_mask(struct buffer_instance *instance)
 {
 	struct stat st;
@@ -4136,6 +4269,7 @@ enum {
 	OPT_nosplice		= 253,
 	OPT_funcstack		= 254,
 	OPT_date		= 255,
+	OPT_cpulist			= 256,
 };
 
 void trace_record (int argc, char **argv)
@@ -4337,6 +4471,7 @@ void trace_record (int argc, char **argv)
 			{"stderr", no_argument, NULL, OPT_stderr},
 			{"by-comm", no_argument, NULL, OPT_bycomm},
 			{"ts-offset", required_argument, NULL, OPT_tsoffset},
+			{"cpu-list", required_argument, NULL, OPT_cpulist},
 			{"max-graph-depth", required_argument, NULL, OPT_max_graph_depth},
 			{"debug", no_argument, NULL, OPT_debug},
 			{"help", no_argument, NULL, '?'},
@@ -4545,6 +4680,9 @@ void trace_record (int argc, char **argv)
 		case 'M':
 			instance->cpumask = alloc_mask_from_hex(optarg);
 			break;
+		case OPT_cpulist:
+			instance->cpumask = alloc_mask_from_list(optarg);
+			break;
 		case 't':
 			if (extract)
 				topt = 1; /* Extract top instance also */
-- 
2.5.5