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-rw-r--r--src/cgroups.cpp117
1 files changed, 117 insertions, 0 deletions
diff --git a/src/cgroups.cpp b/src/cgroups.cpp
new file mode 100644
index 0000000..8091195
--- /dev/null
+++ b/src/cgroups.cpp
@@ -0,0 +1,117 @@
+/* -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+#include <config.h>
+#include "cgroups.h"
+#include "util.h"
+
+#include <map>
+#include <unordered_map>
+#include <utility>
+
+bool
+cgroups_enabled(void)
+{
+ static bool initialized = false;
+ static bool has_cgroups;
+
+ if (not initialized) {
+ initialized = true;
+ has_cgroups = Glib::file_test("/proc/cgroups", Glib::FileTest::FILE_TEST_EXISTS);
+ }
+
+ return has_cgroups;
+}
+
+
+
+static const std::pair<std::string, std::string> &
+parse_cgroup_line(const std::string& line) {
+
+ static std::unordered_map<std::string, std::pair<std::string, std::string>> line_cache;
+
+ auto it = line_cache.insert({line, {"", ""} });
+ if (it.second) { // inserted new
+ std::string::size_type cat_start, name_start;
+
+ if ((cat_start = line.find(':')) != std::string::npos
+ && (name_start = line.find(':', cat_start + 1)) != std::string::npos) {
+
+ // printf("%s %lu %lu\n", line.c_str(), cat_start, name_start);
+ auto cat = line.substr(cat_start + 1, name_start - cat_start - 1);
+ auto name = line.substr(name_start + 1);
+
+ // strip the name= prefix
+ if (cat.find("name=") == 0) {
+ cat.erase(0, 5);
+ }
+
+ if (!name.empty() && name != "/") {
+ it.first->second = {name, cat};
+ }
+ }
+ }
+
+ return it.first->second;
+}
+
+
+static const std::string&
+get_process_cgroup_string(pid_t pid) {
+
+ static std::unordered_map<std::string, std::string> file_cache{ {"", ""} };
+
+ /* read out of /proc/pid/cgroup */
+ auto path = "/proc/" + std::to_string(pid) + "/cgroup";
+ std::string text;
+
+ try {
+ text = Glib::file_get_contents(path);
+ } catch (...) {
+ return file_cache[""];
+ }
+
+ auto it = file_cache.insert({ text, "" });
+
+ if (it.second) { // inserted new
+
+ // name -> [cat...], sorted by name;
+ std::map<std::string, std::vector<std::string>> names;
+
+ std::string::size_type last = 0, eol;
+
+ // for each line in the file
+ while ((eol = text.find('\n', last)) != std::string::npos) {
+ auto line = text.substr(last, eol - last);
+ last = eol + 1;
+
+ const auto& p = parse_cgroup_line(line);
+ if (!p.first.empty()) {
+ names[p.first].push_back(p.second);
+ }
+ }
+
+
+ // name (cat1, cat2), ...
+ // sorted by name, categories
+ std::vector<std::string> groups;
+
+ for (auto& i : names) {
+ std::sort(begin(i.second), end(i.second));
+ std::string cats = procman::join(i.second, ", ");
+ groups.push_back(i.first + " (" + cats + ')');
+ }
+
+ it.first->second = procman::join(groups, ", ");
+ }
+
+ return it.first->second;
+}
+
+
+void get_process_cgroup_info(ProcInfo& info) {
+ if (not cgroups_enabled())
+ return;
+
+ const auto& cgroup_string = get_process_cgroup_string(info.pid);
+ info.cgroup_name = cgroup_string;
+}
+