Add logic to filter the container name (+type) from the CGroup name

2 files changed, 142 insertions, 0 deletions

diff --git a/linux/CGroupUtils.c b/linux/CGroupUtils.c
index d38393f4..3626646b 100644
--- a/linux/CGroupUtils.c
+++ b/linux/CGroupUtils.c
@@ -357,3 +357,144 @@ char* CGroup_filterName(const char* cgroup) {
    s.buf[s.size] = '\0';
    return s.buf;
 }
+
+static bool CGroup_filterContainer_internal(const char* cgroup, StrBuf_state* s, StrBuf_putc_t w) {
+   const char* str_lxc_payload_legacy = "lxc.payload";
+   const char* str_lxc_payload_prefix = "lxc.payload.";
+
+   const char* str_nspawn_scope_prefix = "machine-";
+   const char* str_nspawn_monitor_label = "/supervisor";
+   const char* str_nspawn_payload_label = "/payload";
+
+   const char* str_pod_scope_prefix = "libpod-";
+
+   const char* str_scope_suffix = ".scope";
+
+   while (*cgroup) {
+      if ('/' == *cgroup) {
+         while ('/' == *cgroup)
+            cgroup++;
+
+         continue;
+      }
+
+      const char* labelStart = cgroup;
+      const char* nextSlash = String_strchrnul(labelStart, '/');
+      const size_t labelLen = nextSlash - labelStart;
+
+      if (Label_checkPrefix(labelStart, labelLen, str_lxc_payload_prefix)) {
+         const size_t cgroupNameLen = labelLen - strlen(str_lxc_payload_prefix);
+
+         if (!StrBuf_putsz(s, w, "/lxc:"))
+            return false;
+
+         if (!StrBuf_putsn(s, w, cgroup + strlen(str_lxc_payload_prefix), cgroupNameLen))
+            return false;
+
+         cgroup = nextSlash;
+
+         continue;
+      }
+
+      // LXC legacy cgroup naming
+      if (Label_checkEqual(labelStart, labelLen, str_lxc_payload_legacy)) {
+         labelStart = nextSlash;
+         while (*labelStart == '/')
+            labelStart++;
+
+         nextSlash = String_strchrnul(labelStart, '/');
+         if (nextSlash - labelStart > 0) {
+            if (!StrBuf_putsz(s, w, "/lxc:"))
+               return false;
+
+            if (!StrBuf_putsn(s, w, labelStart, nextSlash - labelStart))
+               return false;
+
+            cgroup = nextSlash;
+            continue;
+         }
+
+         labelStart = cgroup;
+         nextSlash = labelStart + labelLen;
+      }
+
+      if (Label_checkSuffix(labelStart, labelLen, str_scope_suffix)) {
+         const size_t scopeNameLen = labelLen - strlen(str_scope_suffix);
+
+         if (Label_checkPrefix(labelStart, scopeNameLen, str_nspawn_scope_prefix)) {
+            const size_t machineScopeNameLen = scopeNameLen - strlen(str_nspawn_scope_prefix);
+
+            const bool is_monitor = String_startsWith(nextSlash, str_nspawn_monitor_label);
+
+            if (!is_monitor) {
+               if (!StrBuf_putsz(s, w, "/snc:"))
+                  return false;
+
+               if (!StrBuf_putsn(s, w, cgroup + strlen(str_nspawn_scope_prefix), machineScopeNameLen))
+                  return false;
+            }
+
+            cgroup = nextSlash;
+            if (String_startsWith(nextSlash, str_nspawn_monitor_label))
+               cgroup += strlen(str_nspawn_monitor_label);
+            else if (String_startsWith(nextSlash, str_nspawn_payload_label))
+               cgroup += strlen(str_nspawn_payload_label);
+
+            continue;
+         } else if (Label_checkPrefix(labelStart, scopeNameLen, str_pod_scope_prefix)) {
+            const char* nextDot = String_strchrnul(labelStart + strlen(str_pod_scope_prefix), '.');
+
+            if (!StrBuf_putsz(s, w, "/pod:"))
+               return false;
+
+            if (nextDot >= labelStart + scopeNameLen) {
+               nextDot = labelStart + scopeNameLen;
+            }
+
+            if (!StrBuf_putsn(s, w, labelStart + strlen(str_pod_scope_prefix),
+               MINIMUM( nextDot - (labelStart + strlen(str_pod_scope_prefix)), 12)))
+               return false;
+
+            cgroup = nextSlash;
+
+            continue;
+         }
+
+         cgroup = nextSlash;
+
+         continue;
+      }
+
+      cgroup = nextSlash;
+   }
+
+   return true;
+}
+
+char* CGroup_filterContainer(const char* cgroup) {
+   StrBuf_state s = {
+      .buf = NULL,
+      .size = 0,
+      .pos = 0,
+   };
+
+   if (!CGroup_filterContainer_internal(cgroup, &s, StrBuf_putc_count)) {
+      return NULL;
+   }
+
+   if (!s.pos) {
+      return xStrdup("/");
+   }
+
+   s.buf = xCalloc(s.pos + 1, sizeof(char));
+   s.size = s.pos;
+   s.pos = 0;
+
+   if (!CGroup_filterContainer_internal(cgroup, &s, StrBuf_putc_write)) {
+      free(s.buf);
+      return NULL;
+   }
+
+   s.buf[s.size] = '\0';
+   return s.buf;
+}
diff --git a/linux/CGroupUtils.h b/linux/CGroupUtils.h
index ff134374..479919bf 100644
--- a/linux/CGroupUtils.h
+++ b/linux/CGroupUtils.h
@@ -12,5 +12,6 @@ in the source distribution for its full text.
 
 
 char* CGroup_filterName(const char* cgroup);
+char* CGroup_filterContainer(const char* cgroup);
 
 #endif /* HEADER_CGroupUtils */