tools/cgset: add -R option to recursively set variables

Add -R option to recursively set variable(s) passed to cgroups under
<cgroup_path>. This will help users to set a controller setting for
all the cgroups under a cgroup hierarchy, instead of passing the
cgroups multiple times on the command line.

example:
--------
./cgcreate -gcpu,memory:foo -gcpu:memory:foo/ch1 -gcpu,memory:foo/ch2
./cgget -r cpu.shares foo foo/ch1 foo/ch2
foo:
cpu.shares: 1024

foo/ch1:
cpu.shares: 1024

foo/ch2:
cpu.shares: 1024

Without the patch
------------------
./cgset -r cpu.shares=256 foo
./cgget -r cpu.shares foo
foo/ch1 foo/ch2
foo:
cpu.shares: 256

foo/ch1:
cpu.shares: 1024

foo/ch2:
cpu.shares: 1024

With the patch
--------------
./cgset -R -r cpu.shares=512 foo
./cgget  -r cpu.shares foo foo/ch1 foo/ch2
foo:
cpu.shares: 512

foo/ch1:
cpu.shares: 512

foo/ch2:
cpu.shares: 512

[check for ECGEOF recommend by Tom Hromatka]
Signed-off-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Signed-off-by: Tom Hromatka <tom.hromatka@oracle.com>

diff --git a/src/tools/cgset.c b/src/tools/cgset.c
index 57ef1b01400260768966685a94e37a53d95fd0d0..ecd6cfe00fc0290df1d384f882ad741d484759b6 100644 (file)
--- a/src/tools/cgset.c
+++ b/src/tools/cgset.c
@@ -9,6 +9,7 @@
 #include <unistd.h>
 #include <getopt.h>
 #include <stdio.h>
+#include <errno.h>
 
 #define FL_RULES       1
 #define FL_COPY                2
@@ -56,7 +57,7 @@ scgroup_err:
        return NULL;
 }
 
-static int cgroup_set_cgroup_values(struct cgroup *src_cgrp, const char * const new_cgrp)
+static struct cgroup *create_and_copy_cgroup(struct cgroup *src_cgrp, const char * const new_cgrp)
 {
        struct cgroup *cgrp;
        int ret = 0;
@@ -64,9 +65,8 @@ static int cgroup_set_cgroup_values(struct cgroup *src_cgrp, const char * const
        /* create new cgroup */
        cgrp = cgroup_new_cgroup(new_cgrp);
        if (!cgrp) {
-               ret = ECGFAIL;
                err("%s: can't add new cgroup: %s\n", program_name, cgroup_strerror(ret));
-               return ret;
+               return NULL;
        }
 
        /* copy the values from the source cgroup to new one */
@@ -77,11 +77,143 @@ static int cgroup_set_cgroup_values(struct cgroup *src_cgrp, const char * const
                goto err;
        }
 
+       return cgrp;
+
+err:
+       cgroup_free(&cgrp);
+       return NULL;
+}
+
+static int cgroup_set_cgroup_values(struct cgroup *src_cgrp, const char * const new_cgrp)
+{
+       struct cgroup *cgrp;
+       int ret = ECGFAIL;
+
+       cgrp = create_and_copy_cgroup(src_cgrp, new_cgrp);
+       if (!cgrp)
+               return ret;
+
        /* modify cgroup based on values of the new one */
        ret = cgroup_modify_cgroup(cgrp);
        if (ret)
                err("%s: cgroup modify error: %s\n", program_name, cgroup_strerror(ret));
 
+       cgroup_free(&cgrp);
+       return ret;
+}
+
+static int _cgroup_set_cgroup_values_r(struct cgroup *src_cgrp, const char * const new_cgrp)
+{
+       struct cgroup_file_info info;
+       int prefix_len;
+       void *handle;
+       int lvl, ret;
+
+
+       ret = cgroup_walk_tree_begin(src_cgrp->controller[0]->name, new_cgrp, 0, &handle, &info,
+                       &lvl);
+       if (ret) {
+               err("%s: failed to walk the tree for cgroup %s controller %s\n",
+                   program_name, new_cgrp, src_cgrp->controller[0]->name);
+
+               return ret;
+       }
+
+       prefix_len = strlen(info.full_path) - strlen(new_cgrp) - 1;
+       ret = cgroup_set_cgroup_values(src_cgrp, &info.full_path[prefix_len]);
+       if (ret)
+               goto err;
+
+       while ((ret = cgroup_walk_tree_next(0, &handle, &info, lvl)) == 0) {
+               if (info.type == CGROUP_FILE_TYPE_DIR) {
+
+                       ret = cgroup_set_cgroup_values(src_cgrp, &info.full_path[prefix_len]);
+                       if (ret)
+                               goto err;
+               }
+       }
+
+err:
+       if (ret == ECGEOF)
+               ret = 0; /* we successfully walked the tree */
+
+       cgroup_walk_tree_end(&handle);
+       return ret;
+}
+
+static int cgroup_copy_controller_idx(struct cgroup *dst_cgrp, struct cgroup *src_cgrp, int idx)
+{
+       struct cgroup_controller *src_cgc = src_cgrp->controller[idx];
+       struct cgroup_controller *dst_cgc = NULL;
+       int ret, i;
+
+       dst_cgc = cgroup_add_controller(dst_cgrp, src_cgc->name);
+       if (!dst_cgc) {
+               err("%s: failed to add controller %s to %s\n", program_name, src_cgc->name,
+                                                              dst_cgrp->name);
+               return ECGFAIL;
+       }
+
+       for (i = 0; i < src_cgc->index; i++) {
+               ret = cgroup_add_value_string(dst_cgc, src_cgc->values[i]->name,
+                                             src_cgc->values[i]->value);
+               if (ret) {
+                       err("%s: Failed to add value %s to cgroup %s controller %s\n",
+                           program_name, src_cgc->values[i]->name, dst_cgrp->name, src_cgc->name);
+                       return ret;
+               }
+       }
+
+       return 0;
+}
+
+static int cgroup_set_cgroup_values_r(struct cgroup *src_cgrp, const char * const new_cgrp)
+{
+       struct cgroup *cgrp;
+       int i, ret = ECGFAIL;
+
+       if (is_cgroup_mode_unified()) {
+               cgrp = create_and_copy_cgroup(src_cgrp, new_cgrp);
+               if (!cgrp)
+                       return ret;
+
+               ret = _cgroup_set_cgroup_values_r(cgrp, new_cgrp);
+               goto err;
+       }
+
+       /*
+        * for non-unified mode, split every controller and walk the
+        * tree. Unlike unified mode the cgroups in the controller
+        * hierarchy might differ, hence walk per controller.
+        *
+        *          cpu       memory
+        *         /  \         |
+        *        a   a1        a
+        *        |           /   \
+        *        b1         b1   b2
+        *        |               |
+        *        c               c
+        */
+       cgrp = cgroup_new_cgroup(new_cgrp);
+       if (!cgrp) {
+               err("%s: can't add new cgroup: %s\n", program_name, cgroup_strerror(ret));
+               return ret;
+       }
+
+       for (i = 0; i < src_cgrp->index; i++) {
+               cgroup_free_controllers(cgrp);
+
+               ret = cgroup_copy_controller_idx(cgrp, src_cgrp, i);
+               if (ret)
+                       goto err;
+
+               ret = _cgroup_set_cgroup_values_r(cgrp, new_cgrp);
+               if (ret)
+                       goto err;
+       }
+
+       ret = 0;
+
 err:
        cgroup_free(&cgrp);
        return ret;
@@ -105,6 +237,8 @@ static void usage(int status)
        info("  -b                                      Ignore default systemd ");
        info("delegate hierarchy\n");
 #endif
+       info("  -R                                      Recursively set variable(s)");
+       info(" for cgroups under <cgroup_path>\n");
 }
 #endif /* !UNIT_TEST */
 
@@ -168,6 +302,7 @@ int main(int argc, char *argv[])
        int ignore_default_systemd_delegate_slice = 0;
        struct control_value *name_value = NULL;
        int nv_number = 0;
+       int recursive = 0;
        int nv_max = 0;
 
        char src_cg_path[FILENAME_MAX] = "\0";
@@ -186,13 +321,13 @@ int main(int argc, char *argv[])
 
        /* parse arguments */
 #ifdef WITH_SYSTEMD
-       while ((c = getopt_long (argc, argv, "r:hb", long_options, NULL)) != -1) {
+       while ((c = getopt_long (argc, argv, "r:hbR", long_options, NULL)) != -1) {
                switch (c) {
                case 'b':
                        ignore_default_systemd_delegate_slice = 1;
                        break;
 #else
-       while ((c = getopt_long (argc, argv, "r:h", long_options, NULL)) != -1) {
+       while ((c = getopt_long (argc, argv, "r:hR", long_options, NULL)) != -1) {
                switch (c) {
 #endif
                case 'h':
@@ -225,6 +360,7 @@ int main(int argc, char *argv[])
                                goto err;
 
                        nv_number++;
+
                        break;
                case COPY_FROM_OPTION:
                        if (flags != 0) {
@@ -236,6 +372,9 @@ int main(int argc, char *argv[])
                        strncpy(src_cg_path, optarg, FILENAME_MAX);
                        src_cg_path[FILENAME_MAX-1] = '\0';
                        break;
+               case 'R':
+                       recursive = 1;
+                       break;
                default:
                        usage(1);
                        ret = EXIT_BADARGS;
@@ -283,7 +422,10 @@ int main(int argc, char *argv[])
        }
 
        while (optind < argc) {
-               ret = cgroup_set_cgroup_values(src_cgroup, argv[optind]);
+               if (recursive)
+                       ret = cgroup_set_cgroup_values_r(src_cgroup, argv[optind]);
+               else
+                       ret = cgroup_set_cgroup_values(src_cgroup, argv[optind]);
                if (ret)
                        goto err;