cgxget: Add a flag to ignore settings that can't be converted

Add a flag, "-i", to cgxget to ignore settings that can't be
converted from cgroup v1 to cgroup v2 or vice versa.

Some cgroup v1 settings, e.g. cpuset.sched_relax_domain_level,
don't have a cgroup v2 equivalent and likely never will.  This
flag allows users to ignore errors from these unconvertable
settings.

Signed-off-by: Tom Hromatka <tom.hromatka@oracle.com>
Reviewed-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>

diff --git a/src/tools/cgxget.c b/src/tools/cgxget.c
index b82474ff4e667de06ee2fcc54dd0bce335e9aa9c..1fae5e875471a59cfb369004f79a8a40190b073c 100644 (file)
--- a/src/tools/cgxget.c
+++ b/src/tools/cgxget.c
@@ -41,6 +41,7 @@ static struct option const long_options[] =
 {
        {"v1", no_argument, NULL, '1'},
        {"v2", no_argument, NULL, '2'},
+       {"ignore-unmappable", no_argument, NULL, 'i'},
        {"variable", required_argument, NULL, 'r'},
        {"help", no_argument, NULL, 'h'},
        {"all",  no_argument, NULL, 'a'},
@@ -65,6 +66,8 @@ static void usage(int status, const char *program_name)
               "v1 format\n");
        printf("  -2, --v2                      Provided parameters are in "
               "v2 format\n");
+       printf("  -i, --ignore-unmappable       Do not return an error for settings "
+              "that cannot be converted\n");
        printf("  -a, --all                     Print info about all relevant "
               "controllers\n");
        printf("  -g <controllers>              Controller which info should "
@@ -413,7 +416,8 @@ out:
 }
 static int parse_opts(int argc, char *argv[], struct cgroup **cg_list[],
                      int * const cg_list_len, int * const mode,
-                     enum cg_version_t * const version)
+                     enum cg_version_t * const version,
+                     bool * const ignore_unmappable)
 {
        bool do_not_fill_controller = false;
        bool fill_controller = false;
@@ -422,7 +426,7 @@ static int parse_opts(int argc, char *argv[], struct cgroup **cg_list[],
        int c;
 
        /* Parse arguments. */
-       while ((c = getopt_long(argc, argv, "r:hnvg:a12", long_options, NULL))
+       while ((c = getopt_long(argc, argv, "r:hnvg:a12i", long_options, NULL))
                > 0) {
                switch (c) {
                case 'h':
@@ -470,6 +474,9 @@ static int parse_opts(int argc, char *argv[], struct cgroup **cg_list[],
                case '2':
                        *version = CGROUP_V2;
                        break;
+               case 'i':
+                       *ignore_unmappable = true;
+                       break;
                default:
                        usage(1, argv[0]);
                        exit(1);
@@ -786,12 +793,15 @@ int convert_cgroups(struct cgroup **cg_list[], int cg_list_len,
        }
 
 out:
-       if (ret) {
-               /* the conversion failed */
+       if (ret != 0 && ret != ECGNOVERSIONCONVERT) {
+               /* The conversion failed */
                for (j = 0; j < i; j++)
                        cgroup_free(&(cg_converted_list[i]));
        } else {
-               /* the conversion succeeded.  free the old list */
+               /*
+                * The conversion succeeded or was unmappable.  Free the old
+                * list.
+                */
                for (i = 0; i < cg_list_len; i++)
                        cgroup_free(cg_list[i]);
 
@@ -808,6 +818,7 @@ int main(int argc, char *argv[])
        int ret = 0, i;
        int mode = MODE_SHOW_NAMES | MODE_SHOW_HEADERS;
        enum cg_version_t version = CGROUP_UNK;
+       bool ignore_unmappable = false;
 
        /* No parameter on input? */
        if (argc < 2) {
@@ -822,12 +833,18 @@ int main(int argc, char *argv[])
                goto err;
        }
 
-       ret = parse_opts(argc, argv, &cg_list, &cg_list_len, &mode, &version);
+       ret = parse_opts(argc, argv, &cg_list, &cg_list_len, &mode, &version,
+                        &ignore_unmappable);
        if (ret)
                goto err;
 
        ret = convert_cgroups(&cg_list, cg_list_len, version, CGROUP_DISK);
-       if (ret)
+       if (ret == ECGNOVERSIONCONVERT && ignore_unmappable)
+               /* The user has specified that we should ignore any errors
+                * due to being unable to map from v1 to v2 or vice versa
+               */
+               ret = 0;
+       else if (ret)
                goto err;
 
        ret = get_values(cg_list, cg_list_len);