This patch adds cgset tool

This patch adds cgset tool, which sets parameters of controllers
for given cgroup based on input name-variable pairs
- the syntax is:

cgset -r <name=value> <relative path to cgroup>

-------------------------------------------------
EXAMPLES:
$ cgcreate -g cpuset:test1
$ cgset -r cpuset.cpus=1 test
$ cat ./test/cpuset.cpus
1

$ cgcreate -g cpuset:test1 -g cpuset:test2
$ cgset -r cpuset.cpus=0 test1 test2
$ cat /mnt/cgroups/cpuset/test1/cpuset.cpus
0
$ cat /mnt/cgroups/cpuset/test2/cpuset.cpus
0

Signed-off-by: Ivana Varekova <varekova@redhat.com>
Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>

2 files changed, 179 insertions, 1 deletions

diff --git a/src/tools/Makefile.am b/src/tools/Makefile.am
index 73f9130..2b4c9e7 100644
--- a/src/tools/Makefile.am
+++ b/src/tools/Makefile.am
@@ -3,7 +3,7 @@ LDADD = $(top_srcdir)/src/.libs/libcgroup.la
 
 if WITH_TOOLS
 
-bin_PROGRAMS = cgexec cgclassify cgcreate
+bin_PROGRAMS = cgexec cgclassify cgcreate cgset
 
 sbin_PROGRAMS = cgconfigparser
 
diff --git a/src/tools/cgset.c b/src/tools/cgset.c
new file mode 100644
index 0000000..be234be
--- /dev/null
+++ b/src/tools/cgset.c
@@ -0,0 +1,178 @@
+#include <libcgroup.h>
+#include <libcgroup-internal.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "tools-common.h"
+
+int main(int argc, char *argv[])
+{
+	int ret = 0;
+	int i;
+	char c;
+
+	char *buf;
+	char con[FILENAME_MAX];
+	struct control_value *name_value = NULL;
+	int nv_number = 0;
+	int nv_max = 0;
+
+	struct cgroup *cgroup;
+	struct cgroup_controller *cgc;
+
+	/* no parametr on input */
+	if (argc < 2) {
+		fprintf(stderr, "Usage is %s -r <name=value> "
+			"<relative path to cgroup>\n", argv[0]);
+		return -1;
+	}
+
+	/* parse arguments */
+	while ((c = getopt(argc, argv, "r:")) > 0) {
+		switch (c) {
+		case 'r':
+			/* add name-value pair to buffer
+				(= name_value variable) */
+			if (nv_number >= nv_max) {
+				nv_max += CG_NV_MAX;
+				name_value = (struct control_value *)
+					realloc(name_value,
+					nv_max * sizeof(struct control_value));
+				if (!name_value) {
+					fprintf(stderr, "cgset: "
+						"not enough memory\n");
+					ret = -1;
+					goto err;
+				}
+			}
+
+			/* parse optarg value */
+			/* there is necessary to input the tuple n=v */
+			buf = strtok(optarg, "=");
+			if (buf == NULL) {
+				fprintf(stderr, "%s: "
+					"wrong parameter of option -r: %s\n",
+					argv[0], optarg);
+				ret = -1;
+				goto err;
+			}
+
+			strncpy(name_value[nv_number].name, buf, FILENAME_MAX);
+			name_value[nv_number].name[FILENAME_MAX-1] = '\0';
+
+			buf = strtok(NULL, "=");
+			if (buf == NULL) {
+				fprintf(stderr, "%s: "
+					"wrong parameter of option -r: %s\n",
+					argv[0], optarg);
+				ret = -1;
+				goto err;
+			}
+
+			strncpy(name_value[nv_number].value, buf, CG_VALUE_MAX);
+			name_value[nv_number].value[CG_VALUE_MAX-1] = '\0';
+
+			nv_number++;
+			break;
+		default:
+			fprintf(stderr, "%s: invalid command line option\n",
+				argv[0]);
+			ret = -1;
+			goto err;
+			break;
+		}
+	}
+
+	/* no cgroup name */
+	if (!argv[optind]) {
+		fprintf(stderr, "%s: no cgroup specified\n", argv[0]);
+		ret = -1;
+		goto err;
+	}
+
+	if (nv_number == 0) {
+		fprintf(stderr, "%s: no name-value pair was set\n", argv[0]);
+		ret = -1;
+		goto err;
+	}
+
+	/* initialize libcgroup */
+	ret = cgroup_init();
+	if (ret) {
+		fprintf(stderr, "%s: libcgroup initialization failed: %s\n",
+			argv[0], cgroup_strerror(ret));
+		goto err;
+	}
+
+	while (optind < argc) {
+
+		/* create new cgroup */
+		cgroup = cgroup_new_cgroup(argv[optind]);
+		if (!cgroup) {
+			ret = ECGFAIL;
+			fprintf(stderr, "%s: can't add new cgroup: %s\n",
+				argv[0], cgroup_strerror(ret));
+			ret = -1;
+			goto err;
+		}
+
+		/* add pairs name-value to
+		   relevant controllers of this cgroup */
+		for (i = 0; i < nv_number; i++) {
+
+			if ((strchr(name_value[i].name, '.')) == NULL) {
+				fprintf(stderr, "%s: "
+					"wrong -r  parameter (%s=%s)\n",
+					argv[0], name_value[i].name,
+					name_value[i].value);
+				ret = -1;
+				goto cgroup_free_err;
+			}
+
+			strncpy(con, name_value[i].name, FILENAME_MAX);
+			strtok(con, ".");
+
+			/* add relevant controller */
+			cgc = cgroup_add_controller(cgroup, con);
+			if (!cgc) {
+				fprintf(stderr, "%s: "
+					"controller %s can't be add\n",
+					argv[0], con);
+				goto cgroup_free_err;
+			}
+
+			/* add name-value pair to this controller */
+			ret = cgroup_add_value_string(cgc,
+				name_value[i].name, name_value[i].value);
+			if (ret) {
+				fprintf(stderr, "%s: "
+					"name-value pair %s=%s "
+					"can't be set\n",
+					argv[0], name_value[i].name,
+					name_value[i].value);
+				goto cgroup_free_err;
+			}
+		}
+
+		/* modify cgroup */
+		ret = cgroup_modify_cgroup(cgroup);
+		if (ret) {
+			fprintf(stderr, "%s: "
+				"the group can't be modified\n",
+				argv[0]);
+			goto cgroup_free_err;
+		}
+
+		optind++;
+		cgroup_free(&cgroup);
+	}
+cgroup_free_err:
+	if (ret)
+		cgroup_free(&cgroup);
+err:
+	free(name_value);
+	return ret;
+}