From 26d086f98690646319cf6d7809072f74ccc41795 Mon Sep 17 00:00:00 2001
From: Wiktor Garbacz <wiktorg@google.com>
Date: Thu, 26 Jul 2018 14:16:55 +0200
Subject: [PATCH] cgroup: refactor cgroup code
Extract common functions, use c++ strings.
Fixes #83
---
cgroup.cc | 290 +++++++++++++++++++++-----------------------------------------
util.h | 7 ++
2 files changed, 106 insertions(+), 191 deletions(-)
diff --git a/cgroup.cc b/cgroup.cc
index cc8b94b..91a09ce 100644
--- a/cgroup.cc
+++ b/cgroup.cc
@@ -30,54 +30,62 @@
#include <sys/stat.h>
#include <unistd.h>
+#include <sstream>
+
#include "logs.h"
#include "util.h"
namespace cgroup {
+static bool createCgroup(const std::string& cgroup_path, pid_t pid) {
+ LOG_D("Create '%s' for PID=%d", cgroup_path.c_str(), (int)pid);
+ if (mkdir(cgroup_path.c_str(), 0700) == -1 && errno != EEXIST) {
+ PLOG_W("mkdir('%s', 0700) failed", cgroup_path.c_str());
+ return false;
+ }
+
+ return true;
+}
+
+static bool writeToCgroup(
+ const std::string& cgroup_path, const std::string& value, const std::string& what) {
+ LOG_D("Setting '%s' to '%s'", cgroup_path.c_str(), value.c_str());
+ if (!util::writeBufToFile(
+ cgroup_path.c_str(), value.c_str(), value.length(), O_WRONLY | O_CLOEXEC)) {
+ LOG_W("Could not update %s", what.c_str());
+ return false;
+ }
+
+ return true;
+}
+
+static bool addPidToTaskList(const std::string& cgroup_path, pid_t pid) {
+ std::string pid_str = std::to_string(pid);
+ std::string tasks_path = cgroup_path + "/tasks";
+ LOG_D("Adding PID='%s' to '%s'", pid_str.c_str(), tasks_path.c_str());
+ return writeToCgroup(tasks_path, pid_str, "'" + tasks_path + "' task list");
+}
+
static bool initNsFromParentMem(nsjconf_t* nsjconf, pid_t pid) {
if (nsjconf->cgroup_mem_max == (size_t)0) {
return true;
}
- char mem_cgroup_path[PATH_MAX];
- snprintf(mem_cgroup_path, sizeof(mem_cgroup_path), "%s/%s/NSJAIL.%d",
- nsjconf->cgroup_mem_mount.c_str(), nsjconf->cgroup_mem_parent.c_str(), (int)pid);
- LOG_D("Create '%s' for PID=%d", mem_cgroup_path, (int)pid);
- if (mkdir(mem_cgroup_path, 0700) == -1 && errno != EEXIST) {
- PLOG_W("mkdir('%s', 0700) failed", mem_cgroup_path);
- return false;
- }
+ std::string mem_cgroup_path = nsjconf->cgroup_mem_mount + '/' + nsjconf->cgroup_mem_parent +
+ "/NSJAIL." + std::to_string(pid);
+ RETURN_ON_FAILURE(createCgroup(mem_cgroup_path, pid));
- char fname[PATH_MAX];
std::string mem_max_str = std::to_string(nsjconf->cgroup_mem_max);
- snprintf(fname, sizeof(fname), "%s/memory.limit_in_bytes", mem_cgroup_path);
- LOG_D("Setting '%s' to '%s'", fname, mem_max_str.c_str());
- if (!util::writeBufToFile(
- fname, mem_max_str.data(), mem_max_str.length(), O_WRONLY | O_CLOEXEC)) {
- LOG_W("Could not update memory cgroup max limit");
- return false;
- }
+ RETURN_ON_FAILURE(writeToCgroup(
+ mem_cgroup_path + "/memory.limit_in_bytes", mem_max_str, "memory cgroup max limit"));
/*
* Use OOM-killer instead of making processes hang/sleep
*/
- snprintf(fname, sizeof(fname), "%s/memory.oom_control", mem_cgroup_path);
- LOG_D("Writting '0' '%s'", fname);
- if (!util::writeBufToFile(fname, "0", strlen("0"), O_WRONLY | O_CLOEXEC)) {
- LOG_W("Could not update memory cgroup oom control");
- return false;
- }
-
- std::string pid_str = std::to_string(pid);
- snprintf(fname, sizeof(fname), "%s/tasks", mem_cgroup_path);
- LOG_D("Adding PID='%s' to '%s'", pid_str.c_str(), fname);
- if (!util::writeBufToFile(fname, pid_str.data(), pid_str.length(), O_WRONLY | O_CLOEXEC)) {
- LOG_W("Could not update '%s' task list", fname);
- return false;
- }
+ RETURN_ON_FAILURE(writeToCgroup(
+ mem_cgroup_path + "/memory.oom_control", "0", "memory cgroup oom control"));
- return true;
+ return addPidToTaskList(mem_cgroup_path, pid);
}
static bool initNsFromParentPids(nsjconf_t* nsjconf, pid_t pid) {
@@ -85,34 +93,16 @@ static bool initNsFromParentPids(nsjconf_t* nsjconf, pid_t pid) {
return true;
}
- char pids_cgroup_path[PATH_MAX];
- snprintf(pids_cgroup_path, sizeof(pids_cgroup_path), "%s/%s/NSJAIL.%d",
- nsjconf->cgroup_pids_mount.c_str(), nsjconf->cgroup_pids_parent.c_str(), (int)pid);
- LOG_D("Create '%s' for PID=%d", pids_cgroup_path, (int)pid);
- if (mkdir(pids_cgroup_path, 0700) == -1 && errno != EEXIST) {
- PLOG_W("mkdir('%s', 0700) failed", pids_cgroup_path);
- return false;
- }
+ std::string pids_cgroup_path = nsjconf->cgroup_pids_mount + '/' +
+ nsjconf->cgroup_pids_parent + "/NSJAIL." +
+ std::to_string(pid);
+ RETURN_ON_FAILURE(createCgroup(pids_cgroup_path, pid));
- char fname[PATH_MAX];
std::string pids_max_str = std::to_string(nsjconf->cgroup_pids_max);
- snprintf(fname, sizeof(fname), "%s/pids.max", pids_cgroup_path);
- LOG_D("Setting '%s' to '%s'", fname, pids_max_str.c_str());
- if (!util::writeBufToFile(
- fname, pids_max_str.data(), pids_max_str.length(), O_WRONLY | O_CLOEXEC)) {
- LOG_W("Could not update pids cgroup max limit");
- return false;
- }
-
- std::string pid_str = std::to_string(pid);
- snprintf(fname, sizeof(fname), "%s/tasks", pids_cgroup_path);
- LOG_D("Adding PID='%s' to '%s'", pid_str.c_str(), fname);
- if (!util::writeBufToFile(fname, pid_str.data(), pid_str.length(), O_WRONLY | O_CLOEXEC)) {
- LOG_W("Could not update '%s' task list", fname);
- return false;
- }
+ RETURN_ON_FAILURE(
+ writeToCgroup(pids_cgroup_path + "/pids.max", pids_max_str, "pids cgroup max limit"));
- return true;
+ return addPidToTaskList(pids_cgroup_path, pid);
}
static bool initNsFromParentNetCls(nsjconf_t* nsjconf, pid_t pid) {
@@ -120,37 +110,21 @@ static bool initNsFromParentNetCls(nsjconf_t* nsjconf, pid_t pid) {
return true;
}
- char net_cls_cgroup_path[PATH_MAX];
- snprintf(net_cls_cgroup_path, sizeof(net_cls_cgroup_path), "%s/%s/NSJAIL.%d",
- nsjconf->cgroup_net_cls_mount.c_str(), nsjconf->cgroup_net_cls_parent.c_str(),
- (int)pid);
- LOG_D("Create '%s' for PID=%d", net_cls_cgroup_path, (int)pid);
- if (mkdir(net_cls_cgroup_path, 0700) == -1 && errno != EEXIST) {
- PLOG_W("mkdir('%s', 0700) failed", net_cls_cgroup_path);
- return false;
- }
-
- char fname[PATH_MAX];
- char net_cls_classid_str[512];
- snprintf(net_cls_classid_str, sizeof(net_cls_classid_str), "0x%x",
- nsjconf->cgroup_net_cls_classid);
- snprintf(fname, sizeof(fname), "%s/net_cls.classid", net_cls_cgroup_path);
- LOG_D("Setting '%s' to '%s'", fname, net_cls_classid_str);
- if (!util::writeBufToFile(
- fname, net_cls_classid_str, strlen(net_cls_classid_str), O_WRONLY | O_CLOEXEC)) {
- LOG_W("Could not update net_cls cgroup classid");
- return false;
- }
+ std::string net_cls_cgroup_path = nsjconf->cgroup_net_cls_mount + '/' +
+ nsjconf->cgroup_net_cls_parent + "/NSJAIL." +
+ std::to_string(pid);
+ RETURN_ON_FAILURE(createCgroup(net_cls_cgroup_path, pid));
- std::string pid_str = std::to_string(pid);
- snprintf(fname, sizeof(fname), "%s/tasks", net_cls_cgroup_path);
- LOG_D("Adding PID='%s' to '%s'", pid_str.c_str(), fname);
- if (!util::writeBufToFile(fname, pid_str.data(), pid_str.length(), O_WRONLY | O_CLOEXEC)) {
- LOG_W("Could not update '%s' task list", fname);
- return false;
+ std::string net_cls_classid_str;
+ {
+ std::stringstream ss;
+ ss << "0x" << std::hex << nsjconf->cgroup_net_cls_classid;
+ net_cls_classid_str = ss.str();
}
+ RETURN_ON_FAILURE(writeToCgroup(net_cls_cgroup_path + "/net_cls.classid",
+ net_cls_classid_str, "net_cls cgroup classid"));
- return true;
+ return addPidToTaskList(net_cls_cgroup_path, pid);
}
static bool initNsFromParentCpu(nsjconf_t* nsjconf, pid_t pid) {
@@ -158,125 +132,59 @@ static bool initNsFromParentCpu(nsjconf_t* nsjconf, pid_t pid) {
return true;
}
- char cpu_cgroup_path[PATH_MAX];
- snprintf(cpu_cgroup_path, sizeof(cpu_cgroup_path), "%s/%s/NSJAIL.%d",
- nsjconf->cgroup_cpu_mount.c_str(), nsjconf->cgroup_cpu_parent.c_str(), (int)pid);
- LOG_D("Create '%s' for PID=%d", cpu_cgroup_path, (int)pid);
- if (mkdir(cpu_cgroup_path, 0700) == -1 && errno != EEXIST) {
- PLOG_W("mkdir('%s', 0700) failed", cpu_cgroup_path);
- return false;
- }
+ std::string cpu_cgroup_path = nsjconf->cgroup_cpu_mount + '/' + nsjconf->cgroup_cpu_parent +
+ "/NSJAIL." + std::to_string(pid);
+ RETURN_ON_FAILURE(createCgroup(cpu_cgroup_path, pid));
- char fname[PATH_MAX];
- char cpu_ms_per_sec_str[512];
- snprintf(cpu_ms_per_sec_str, sizeof(cpu_ms_per_sec_str), "%u",
- nsjconf->cgroup_cpu_ms_per_sec * 1000U);
- snprintf(fname, sizeof(fname), "%s/cpu.cfs_quota_us", cpu_cgroup_path);
- LOG_D("Setting '%s' to '%s'", fname, cpu_ms_per_sec_str);
- if (!util::writeBufToFile(
- fname, cpu_ms_per_sec_str, strlen(cpu_ms_per_sec_str), O_WRONLY | O_CLOEXEC)) {
- LOG_W("Could not update cpu quota");
- return false;
- }
-
- static const char cpu_period_us[] = "1000000";
- snprintf(fname, sizeof(fname), "%s/cpu.cfs_period_us", cpu_cgroup_path);
- LOG_D("Setting '%s' to '%s'", fname, cpu_period_us);
- if (!util::writeBufToFile(
- fname, cpu_period_us, strlen(cpu_period_us), O_WRONLY | O_CLOEXEC)) {
- LOG_W("Could not update cpu period");
- return false;
- }
+ std::string cpu_ms_per_sec_str = std::to_string(nsjconf->cgroup_cpu_ms_per_sec * 1000U);
+ RETURN_ON_FAILURE(
+ writeToCgroup(cpu_cgroup_path + "/cpu.cfs_quota_us", cpu_ms_per_sec_str, "cpu quota"));
- std::string pid_str = std::to_string(pid);
- snprintf(fname, sizeof(fname), "%s/tasks", cpu_cgroup_path);
- LOG_D("Adding PID='%s' to '%s'", pid_str.c_str(), fname);
- if (!util::writeBufToFile(fname, pid_str.data(), pid_str.length(), O_WRONLY | O_CLOEXEC)) {
- LOG_W("Could not update '%s' task list", fname);
- return false;
- }
+ RETURN_ON_FAILURE(
+ writeToCgroup(cpu_cgroup_path + "/cpu.cfs_period_us", "1000000", "cpu period"));
- return true;
+ return addPidToTaskList(cpu_cgroup_path, pid);
}
bool initNsFromParent(nsjconf_t* nsjconf, pid_t pid) {
- if (!initNsFromParentMem(nsjconf, pid)) {
- return false;
- }
- if (!initNsFromParentPids(nsjconf, pid)) {
- return false;
- }
- if (!initNsFromParentNetCls(nsjconf, pid)) {
- return false;
- }
- if (!initNsFromParentCpu(nsjconf, pid)) {
- return false;
- }
- return true;
-}
-
-void finishFromParentMem(nsjconf_t* nsjconf, pid_t pid) {
- if (nsjconf->cgroup_mem_max == (size_t)0) {
- return;
- }
- char mem_cgroup_path[PATH_MAX];
- snprintf(mem_cgroup_path, sizeof(mem_cgroup_path), "%s/%s/NSJAIL.%d",
- nsjconf->cgroup_mem_mount.c_str(), nsjconf->cgroup_mem_parent.c_str(), (int)pid);
- LOG_D("Remove '%s'", mem_cgroup_path);
- if (rmdir(mem_cgroup_path) == -1) {
- PLOG_W("rmdir('%s') failed", mem_cgroup_path);
- }
- return;
-}
-
-void finishFromParentPids(nsjconf_t* nsjconf, pid_t pid) {
- if (nsjconf->cgroup_pids_max == 0U) {
- return;
- }
- char pids_cgroup_path[PATH_MAX];
- snprintf(pids_cgroup_path, sizeof(pids_cgroup_path), "%s/%s/NSJAIL.%d",
- nsjconf->cgroup_pids_mount.c_str(), nsjconf->cgroup_pids_parent.c_str(), (int)pid);
- LOG_D("Remove '%s'", pids_cgroup_path);
- if (rmdir(pids_cgroup_path) == -1) {
- PLOG_W("rmdir('%s') failed", pids_cgroup_path);
- }
- return;
+ RETURN_ON_FAILURE(initNsFromParentMem(nsjconf, pid));
+ RETURN_ON_FAILURE(initNsFromParentPids(nsjconf, pid));
+ RETURN_ON_FAILURE(initNsFromParentNetCls(nsjconf, pid));
+ return initNsFromParentCpu(nsjconf, pid);
}
-void finishFromParentCpu(nsjconf_t* nsjconf, pid_t pid) {
- if (nsjconf->cgroup_cpu_ms_per_sec == 0U) {
- return;
- }
- char cpu_cgroup_path[PATH_MAX];
- snprintf(cpu_cgroup_path, sizeof(cpu_cgroup_path), "%s/%s/NSJAIL.%d",
- nsjconf->cgroup_cpu_mount.c_str(), nsjconf->cgroup_cpu_parent.c_str(), (int)pid);
- LOG_D("Remove '%s'", cpu_cgroup_path);
- if (rmdir(cpu_cgroup_path) == -1) {
- PLOG_W("rmdir('%s') failed", cpu_cgroup_path);
+static void removeCgroup(const std::string& cgroup_path) {
+ LOG_D("Remove '%s'", cgroup_path.c_str());
+ if (rmdir(cgroup_path.c_str()) == -1) {
+ PLOG_W("rmdir('%s') failed", cgroup_path.c_str());
}
- return;
-}
-
-void finishFromParentNetCls(nsjconf_t* nsjconf, pid_t pid) {
- if (nsjconf->cgroup_net_cls_classid == 0U) {
- return;
- }
- char net_cls_cgroup_path[PATH_MAX];
- snprintf(net_cls_cgroup_path, sizeof(net_cls_cgroup_path), "%s/%s/NSJAIL.%d",
- nsjconf->cgroup_net_cls_mount.c_str(), nsjconf->cgroup_net_cls_parent.c_str(),
- (int)pid);
- LOG_D("Remove '%s'", net_cls_cgroup_path);
- if (rmdir(net_cls_cgroup_path) == -1) {
- PLOG_W("rmdir('%s') failed", net_cls_cgroup_path);
- }
- return;
}
void finishFromParent(nsjconf_t* nsjconf, pid_t pid) {
- finishFromParentMem(nsjconf, pid);
- finishFromParentPids(nsjconf, pid);
- finishFromParentNetCls(nsjconf, pid);
- finishFromParentCpu(nsjconf, pid);
+ if (nsjconf->cgroup_mem_max != (size_t)0) {
+ std::string mem_cgroup_path = nsjconf->cgroup_mem_mount + '/' +
+ nsjconf->cgroup_mem_parent + "/NSJAIL." +
+ std::to_string(pid);
+ removeCgroup(mem_cgroup_path);
+ }
+ if (nsjconf->cgroup_pids_max != 0U) {
+ std::string pids_cgroup_path = nsjconf->cgroup_pids_mount + '/' +
+ nsjconf->cgroup_pids_parent + "/NSJAIL." +
+ std::to_string(pid);
+ removeCgroup(pids_cgroup_path);
+ }
+ if (nsjconf->cgroup_net_cls_classid != 0U) {
+ std::string net_cls_cgroup_path = nsjconf->cgroup_net_cls_mount + '/' +
+ nsjconf->cgroup_net_cls_parent + "/NSJAIL." +
+ std::to_string(pid);
+ removeCgroup(net_cls_cgroup_path);
+ }
+ if (nsjconf->cgroup_cpu_ms_per_sec != 0U) {
+ std::string cpu_cgroup_path = nsjconf->cgroup_cpu_mount + '/' +
+ nsjconf->cgroup_cpu_parent + "/NSJAIL." +
+ std::to_string(pid);
+ removeCgroup(cpu_cgroup_path);
+ }
}
bool initNs(void) {
diff --git a/util.h b/util.h
index 3bf71a5..d87399c 100644
--- a/util.h
+++ b/util.h
@@ -31,6 +31,13 @@
#include "nsjail.h"
+#define RETURN_ON_FAILURE(expr) \
+ do { \
+ if (!(expr)) { \
+ return false; \
+ } \
+ } while (0)
+
namespace util {
ssize_t readFromFd(int fd, void* buf, size_t len);