libprocessgroup: remove legacy C string handling and build for host
Bug: 36970783
Test: kill zygote and see that its children die correctly
Change-Id: I1b0e9a9cdb834a000fec82323d690e3bd288692d
diff --git a/libprocessgroup/processgroup.cpp b/libprocessgroup/processgroup.cpp
index 8526b3a..6dfa697 100644
--- a/libprocessgroup/processgroup.cpp
+++ b/libprocessgroup/processgroup.cpp
@@ -22,6 +22,7 @@
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
+#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
@@ -33,15 +34,19 @@
#include <memory>
#include <mutex>
#include <set>
+#include <string>
#include <thread>
#include <android-base/file.h>
#include <android-base/logging.h>
-#include <android-base/unique_fd.h>
+#include <android-base/stringprintf.h>
+#include <android-base/strings.h>
#include <private/android_filesystem_config.h>
#include <processgroup/processgroup.h>
+using android::base::StartsWith;
+using android::base::StringPrintf;
using android::base::WriteStringToFile;
using namespace std::chrono_literals;
@@ -50,171 +55,58 @@
#define MEM_CGROUP_TASKS "/dev/memcg/apps/tasks"
#define ACCT_CGROUP_PATH "/acct"
-#define PROCESSGROUP_UID_PREFIX "uid_"
-#define PROCESSGROUP_PID_PREFIX "pid_"
#define PROCESSGROUP_CGROUP_PROCS_FILE "/cgroup.procs"
-#define PROCESSGROUP_MAX_UID_LEN 11
-#define PROCESSGROUP_MAX_PID_LEN 11
-#define PROCESSGROUP_MAX_PATH_LEN \
- ((sizeof(MEM_CGROUP_PATH) > sizeof(ACCT_CGROUP_PATH) ? \
- sizeof(MEM_CGROUP_PATH) : sizeof(ACCT_CGROUP_PATH)) + \
- sizeof(PROCESSGROUP_UID_PREFIX) + 1 + \
- PROCESSGROUP_MAX_UID_LEN + \
- sizeof(PROCESSGROUP_PID_PREFIX) + 1 + \
- PROCESSGROUP_MAX_PID_LEN + \
- sizeof(PROCESSGROUP_CGROUP_PROCS_FILE) + \
- 1)
std::once_flag init_path_flag;
-class ProcessGroup {
- public:
- ProcessGroup() : buf_ptr_(buf_), buf_len_(0) {}
-
- bool Open(uid_t uid, int pid);
-
- // Return positive number and sets *pid = next pid in process cgroup on success
- // Returns 0 if there are no pids left in the process cgroup
- // Returns -errno if an error was encountered
- int GetOneAppProcess(pid_t* pid);
-
- private:
- // Returns positive number of bytes filled on success
- // Returns 0 if there was nothing to read
- // Returns -errno if an error was encountered
- int RefillBuffer();
-
- android::base::unique_fd fd_;
- char buf_[128];
- char* buf_ptr_;
- size_t buf_len_;
-};
-
-static const char* getCgroupRootPath() {
- static const char* cgroup_root_path = NULL;
+static const std::string& GetCgroupRootPath() {
+ static std::string cgroup_root_path;
std::call_once(init_path_flag, [&]() {
// Check if mem cgroup is mounted, only then check for write-access to avoid
// SELinux denials
- cgroup_root_path = access(MEM_CGROUP_TASKS, F_OK) || access(MEM_CGROUP_PATH, W_OK) ?
- ACCT_CGROUP_PATH : MEM_CGROUP_PATH;
+ cgroup_root_path =
+ (access(MEM_CGROUP_TASKS, F_OK) || access(MEM_CGROUP_PATH, W_OK) ? ACCT_CGROUP_PATH
+ : MEM_CGROUP_PATH);
});
return cgroup_root_path;
}
-static int convertUidToPath(char *path, size_t size, uid_t uid)
-{
- return snprintf(path, size, "%s/%s%d",
- getCgroupRootPath(),
- PROCESSGROUP_UID_PREFIX,
- uid);
+static std::string ConvertUidToPath(uid_t uid) {
+ return StringPrintf("%s/uid_%d", GetCgroupRootPath().c_str(), uid);
}
-static int convertUidPidToPath(char *path, size_t size, uid_t uid, int pid)
-{
- return snprintf(path, size, "%s/%s%d/%s%d",
- getCgroupRootPath(),
- PROCESSGROUP_UID_PREFIX,
- uid,
- PROCESSGROUP_PID_PREFIX,
- pid);
+static std::string ConvertUidPidToPath(uid_t uid, int pid) {
+ return StringPrintf("%s/uid_%d/pid_%d", GetCgroupRootPath().c_str(), uid, pid);
}
-bool ProcessGroup::Open(uid_t uid, int pid) {
- char path[PROCESSGROUP_MAX_PATH_LEN] = {0};
- convertUidPidToPath(path, sizeof(path), uid, pid);
- strlcat(path, PROCESSGROUP_CGROUP_PROCS_FILE, sizeof(path));
-
- int fd = open(path, O_RDONLY);
- if (fd < 0) return false;
-
- fd_.reset(fd);
-
- LOG(VERBOSE) << "Initialized context for " << path;
-
- return true;
-}
-
-int ProcessGroup::RefillBuffer() {
- memmove(buf_, buf_ptr_, buf_len_);
- buf_ptr_ = buf_;
-
- ssize_t ret = read(fd_, buf_ptr_ + buf_len_, sizeof(buf_) - buf_len_ - 1);
- if (ret < 0) {
- return -errno;
- } else if (ret == 0) {
- return 0;
- }
-
- buf_len_ += ret;
- buf_[buf_len_] = 0;
- LOG(VERBOSE) << "Read " << ret << " to buffer: " << buf_;
-
- assert(buf_len_ <= sizeof(buf_));
-
- return ret;
-}
-
-int ProcessGroup::GetOneAppProcess(pid_t* out_pid) {
- *out_pid = 0;
-
- char* eptr;
- while ((eptr = static_cast<char*>(memchr(buf_ptr_, '\n', buf_len_))) == nullptr) {
- int ret = RefillBuffer();
- if (ret <= 0) return ret;
- }
-
- *eptr = '\0';
- char* pid_eptr = nullptr;
- errno = 0;
- long pid = strtol(buf_ptr_, &pid_eptr, 10);
- if (errno != 0) {
- return -errno;
- }
- if (pid_eptr != eptr) {
- errno = EINVAL;
- return -errno;
- }
-
- buf_len_ -= (eptr - buf_ptr_) + 1;
- buf_ptr_ = eptr + 1;
-
- *out_pid = static_cast<pid_t>(pid);
- return 1;
-}
-
-static int removeProcessGroup(uid_t uid, int pid)
-{
+static int RemoveProcessGroup(uid_t uid, int pid) {
int ret;
- char path[PROCESSGROUP_MAX_PATH_LEN] = {0};
- convertUidPidToPath(path, sizeof(path), uid, pid);
- ret = rmdir(path);
+ auto uid_pid_path = ConvertUidPidToPath(uid, pid);
+ ret = rmdir(uid_pid_path.c_str());
- convertUidToPath(path, sizeof(path), uid);
- rmdir(path);
+ auto uid_path = ConvertUidToPath(uid);
+ rmdir(uid_path.c_str());
return ret;
}
-static void removeUidProcessGroups(const char *uid_path)
-{
- std::unique_ptr<DIR, decltype(&closedir)> uid(opendir(uid_path), closedir);
+static void RemoveUidProcessGroups(const std::string& uid_path) {
+ std::unique_ptr<DIR, decltype(&closedir)> uid(opendir(uid_path.c_str()), closedir);
if (uid != NULL) {
dirent* dir;
while ((dir = readdir(uid.get())) != nullptr) {
- char path[PROCESSGROUP_MAX_PATH_LEN];
-
if (dir->d_type != DT_DIR) {
continue;
}
- if (strncmp(dir->d_name, PROCESSGROUP_PID_PREFIX, strlen(PROCESSGROUP_PID_PREFIX))) {
+ if (!StartsWith(dir->d_name, "pid_")) {
continue;
}
- snprintf(path, sizeof(path), "%s/%s", uid_path, dir->d_name);
+ auto path = StringPrintf("%s/%s", uid_path.c_str(), dir->d_name);
LOG(VERBOSE) << "Removing " << path;
- if (rmdir(path) == -1) PLOG(WARNING) << "Failed to remove " << path;
+ if (rmdir(path.c_str()) == -1) PLOG(WARNING) << "Failed to remove " << path;
}
}
}
@@ -222,38 +114,38 @@
void removeAllProcessGroups()
{
LOG(VERBOSE) << "removeAllProcessGroups()";
- const char* cgroup_root_path = getCgroupRootPath();
- std::unique_ptr<DIR, decltype(&closedir)> root(opendir(cgroup_root_path), closedir);
+ const auto& cgroup_root_path = GetCgroupRootPath();
+ std::unique_ptr<DIR, decltype(&closedir)> root(opendir(cgroup_root_path.c_str()), closedir);
if (root == NULL) {
PLOG(ERROR) << "Failed to open " << cgroup_root_path;
} else {
dirent* dir;
while ((dir = readdir(root.get())) != nullptr) {
- char path[PROCESSGROUP_MAX_PATH_LEN];
-
if (dir->d_type != DT_DIR) {
continue;
}
- if (strncmp(dir->d_name, PROCESSGROUP_UID_PREFIX, strlen(PROCESSGROUP_UID_PREFIX))) {
+
+ if (!StartsWith(dir->d_name, "uid_")) {
continue;
}
- snprintf(path, sizeof(path), "%s/%s", cgroup_root_path, dir->d_name);
- removeUidProcessGroups(path);
+ auto path = StringPrintf("%s/%s", cgroup_root_path.c_str(), dir->d_name);
+ RemoveUidProcessGroups(path);
LOG(VERBOSE) << "Removing " << path;
- if (rmdir(path) == -1) PLOG(WARNING) << "Failed to remove " << path;
+ if (rmdir(path.c_str()) == -1) PLOG(WARNING) << "Failed to remove " << path;
}
}
}
// Returns number of processes killed on success
// Returns 0 if there are no processes in the process cgroup left to kill
-// Returns -errno on error
-static int doKillProcessGroupOnce(uid_t uid, int initialPid, int signal) {
- ProcessGroup process_group;
- if (!process_group.Open(uid, initialPid)) {
+// Returns -1 on error
+static int DoKillProcessGroupOnce(uid_t uid, int initialPid, int signal) {
+ auto path = ConvertUidPidToPath(uid, initialPid) + PROCESSGROUP_CGROUP_PROCS_FILE;
+ std::unique_ptr<FILE, decltype(&fclose)> fd(fopen(path.c_str(), "re"), fclose);
+ if (!fd) {
PLOG(WARNING) << "Failed to open process cgroup uid " << uid << " pid " << initialPid;
- return -errno;
+ return -1;
}
// We separate all of the pids in the cgroup into those pids that are also the leaders of
@@ -262,10 +154,9 @@
pgids.emplace(initialPid);
std::set<pid_t> pids;
- int ret;
pid_t pid;
int processes = 0;
- while ((ret = process_group.GetOneAppProcess(&pid)) > 0 && pid >= 0) {
+ while (fscanf(fd.get(), "%d\n", &pid) == 1 && pid >= 0) {
processes++;
if (pid == 0) {
// Should never happen... but if it does, trying to kill this
@@ -312,15 +203,15 @@
}
}
- return ret >= 0 ? processes : ret;
+ return feof(fd.get()) ? processes : -1;
}
-static int killProcessGroup(uid_t uid, int initialPid, int signal, int retries) {
+static int KillProcessGroup(uid_t uid, int initialPid, int signal, int retries) {
std::chrono::steady_clock::time_point start = std::chrono::steady_clock::now();
int retry = retries;
int processes;
- while ((processes = doKillProcessGroupOnce(uid, initialPid, signal)) > 0) {
+ while ((processes = DoKillProcessGroupOnce(uid, initialPid, signal)) > 0) {
LOG(VERBOSE) << "Killed " << processes << " processes for processgroup " << initialPid;
if (retry > 0) {
std::this_thread::sleep_for(5ms);
@@ -350,7 +241,7 @@
LOG(INFO) << "Successfully killed process cgroup uid " << uid << " pid " << initialPid
<< " in " << static_cast<int>(ms) << "ms";
}
- return removeProcessGroup(uid, initialPid);
+ return RemoveProcessGroup(uid, initialPid);
} else {
if (retries > 0) {
LOG(ERROR) << "Failed to kill process cgroup uid " << uid << " pid " << initialPid
@@ -362,22 +253,21 @@
}
int killProcessGroup(uid_t uid, int initialPid, int signal) {
- return killProcessGroup(uid, initialPid, signal, 40 /*retries*/);
+ return KillProcessGroup(uid, initialPid, signal, 40 /*retries*/);
}
int killProcessGroupOnce(uid_t uid, int initialPid, int signal) {
- return killProcessGroup(uid, initialPid, signal, 0 /*retries*/);
+ return KillProcessGroup(uid, initialPid, signal, 0 /*retries*/);
}
-static bool mkdirAndChown(const char *path, mode_t mode, uid_t uid, gid_t gid)
-{
- if (mkdir(path, mode) == -1 && errno != EEXIST) {
+static bool MkdirAndChown(const std::string& path, mode_t mode, uid_t uid, gid_t gid) {
+ if (mkdir(path.c_str(), mode) == -1 && errno != EEXIST) {
return false;
}
- if (chown(path, uid, gid) == -1) {
+ if (chown(path.c_str(), uid, gid) == -1) {
int saved_errno = errno;
- rmdir(path);
+ rmdir(path.c_str());
errno = saved_errno;
return false;
}
@@ -387,42 +277,38 @@
int createProcessGroup(uid_t uid, int initialPid)
{
- char path[PROCESSGROUP_MAX_PATH_LEN] = {0};
+ auto uid_path = ConvertUidToPath(uid);
- convertUidToPath(path, sizeof(path), uid);
-
- if (!mkdirAndChown(path, 0750, AID_SYSTEM, AID_SYSTEM)) {
- PLOG(ERROR) << "Failed to make and chown " << path;
+ if (!MkdirAndChown(uid_path, 0750, AID_SYSTEM, AID_SYSTEM)) {
+ PLOG(ERROR) << "Failed to make and chown " << uid_path;
return -errno;
}
- convertUidPidToPath(path, sizeof(path), uid, initialPid);
+ auto uid_pid_path = ConvertUidPidToPath(uid, initialPid);
- if (!mkdirAndChown(path, 0750, AID_SYSTEM, AID_SYSTEM)) {
- PLOG(ERROR) << "Failed to make and chown " << path;
+ if (!MkdirAndChown(uid_pid_path, 0750, AID_SYSTEM, AID_SYSTEM)) {
+ PLOG(ERROR) << "Failed to make and chown " << uid_pid_path;
return -errno;
}
- strlcat(path, PROCESSGROUP_CGROUP_PROCS_FILE, sizeof(path));
+ auto uid_pid_procs_file = uid_pid_path + PROCESSGROUP_CGROUP_PROCS_FILE;
int ret = 0;
- if (!WriteStringToFile(std::to_string(initialPid), path)) {
+ if (!WriteStringToFile(std::to_string(initialPid), uid_pid_procs_file)) {
ret = -errno;
- PLOG(ERROR) << "Failed to write '" << initialPid << "' to " << path;
+ PLOG(ERROR) << "Failed to write '" << initialPid << "' to " << uid_pid_procs_file;
}
return ret;
}
-static bool setProcessGroupValue(uid_t uid, int pid, const char* fileName, int64_t value) {
- char path[PROCESSGROUP_MAX_PATH_LEN] = {0};
- if (strcmp(getCgroupRootPath(), MEM_CGROUP_PATH)) {
- PLOG(ERROR) << "Memcg is not mounted." << path;
+static bool SetProcessGroupValue(uid_t uid, int pid, const std::string& file_name, int64_t value) {
+ if (GetCgroupRootPath() != MEM_CGROUP_PATH) {
+ PLOG(ERROR) << "Memcg is not mounted.";
return false;
}
- convertUidPidToPath(path, sizeof(path), uid, pid);
- strlcat(path, fileName, sizeof(path));
+ auto path = ConvertUidPidToPath(uid, pid) + file_name;
if (!WriteStringToFile(std::to_string(value), path)) {
PLOG(ERROR) << "Failed to write '" << value << "' to " << path;
@@ -432,13 +318,13 @@
}
bool setProcessGroupSwappiness(uid_t uid, int pid, int swappiness) {
- return setProcessGroupValue(uid, pid, "/memory.swappiness", swappiness);
+ return SetProcessGroupValue(uid, pid, "/memory.swappiness", swappiness);
}
bool setProcessGroupSoftLimit(uid_t uid, int pid, int64_t soft_limit_in_bytes) {
- return setProcessGroupValue(uid, pid, "/memory.soft_limit_in_bytes", soft_limit_in_bytes);
+ return SetProcessGroupValue(uid, pid, "/memory.soft_limit_in_bytes", soft_limit_in_bytes);
}
bool setProcessGroupLimit(uid_t uid, int pid, int64_t limit_in_bytes) {
- return setProcessGroupValue(uid, pid, "/memory.limit_in_bytes", limit_in_bytes);
+ return SetProcessGroupValue(uid, pid, "/memory.limit_in_bytes", limit_in_bytes);
}