Add libprocessgroup
libprocessgroup will allow Zygote to place processes
in a cgroup, and then kill the process and all forked processes
later. lmkd will also kill all forked processes.
Bug: 15313911
Change-Id: I20404d0dbe448f1c475d2f4c61cccca462f9e544
diff --git a/libprocessgroup/processgroup.cpp b/libprocessgroup/processgroup.cpp
new file mode 100644
index 0000000..c32e741
--- /dev/null
+++ b/libprocessgroup/processgroup.cpp
@@ -0,0 +1,316 @@
+/*
+ * Copyright 2014 Google, Inc
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+//#define LOG_NDEBUG 0
+#define LOG_TAG "libprocessgroup"
+
+#include <assert.h>
+#include <dirent.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include <log/log.h>
+#include <private/android_filesystem_config.h>
+
+#include <processgroup/processgroup.h>
+#include "processgroup_priv.h"
+
+struct ctx {
+ bool initialized;
+ int fd;
+ char buf[128];
+ char *buf_ptr;
+ size_t buf_len;
+};
+
+static int convertUidToPath(char *path, size_t size, uid_t uid)
+{
+ return snprintf(path, size, "%s/%s%d",
+ PROCESSGROUP_CGROUP_PATH,
+ PROCESSGROUP_UID_PREFIX,
+ uid);
+}
+
+static int convertUidPidToPath(char *path, size_t size, uid_t uid, int pid)
+{
+ return snprintf(path, size, "%s/%s%d/%s%d",
+ PROCESSGROUP_CGROUP_PATH,
+ PROCESSGROUP_UID_PREFIX,
+ uid,
+ PROCESSGROUP_PID_PREFIX,
+ pid);
+}
+
+static int initCtx(uid_t uid, int pid, struct ctx *ctx)
+{
+ int ret;
+ 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) {
+ ret = -errno;
+ SLOGV("failed to open %s: %s", path, strerror(errno));
+ return ret;
+ }
+
+ ctx->fd = fd;
+ ctx->buf_ptr = ctx->buf;
+ ctx->buf_len = 0;
+ ctx->initialized = true;
+
+ return 0;
+}
+
+static int refillBuffer(struct ctx *ctx)
+{
+ memmove(ctx->buf, ctx->buf_ptr, ctx->buf_len);
+ ctx->buf_ptr = ctx->buf;
+
+ ssize_t ret = read(ctx->fd, ctx->buf_ptr + ctx->buf_len,
+ sizeof(ctx->buf) - ctx->buf_len);
+ if (ret < 0) {
+ return -errno;
+ } else if (ret == 0) {
+ return 0;
+ }
+
+ ctx->buf_len += ret;
+ assert(ctx->buf_len <= sizeof(ctx->buf));
+
+ return ret;
+}
+
+static pid_t getOneAppProcess(uid_t uid, int appProcessPid, struct ctx *ctx)
+{
+ if (!ctx->initialized) {
+ int ret = initCtx(uid, appProcessPid, ctx);
+ if (ret < 0) {
+ return ret;
+ }
+ }
+
+ char *eptr;
+ while ((eptr = (char *)memchr(ctx->buf_ptr, '\n', ctx->buf_len)) == NULL) {
+ int ret = refillBuffer(ctx);
+ if (ret == 0) {
+ return -ERANGE;
+ }
+ if (ret < 0) {
+ return ret;
+ }
+ }
+
+ *eptr = '\0';
+ char *pid_eptr = NULL;
+ errno = 0;
+ long pid = strtol(ctx->buf_ptr, &pid_eptr, 10);
+ if (errno != 0) {
+ return -errno;
+ }
+ if (pid_eptr != eptr) {
+ return -EINVAL;
+ }
+
+ ctx->buf_ptr = eptr + 1;
+
+ return (pid_t)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);
+
+ convertUidToPath(path, sizeof(path), uid);
+ rmdir(path);
+
+ return ret;
+}
+
+static void removeUidProcessGroups(const char *uid_path)
+{
+ DIR *uid = opendir(uid_path);
+ if (uid != NULL) {
+ struct dirent cur;
+ struct dirent *dir;
+ while ((readdir_r(uid, &cur, &dir) == 0) && dir) {
+ 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))) {
+ continue;
+ }
+
+ snprintf(path, sizeof(path), "%s/%s", uid_path, dir->d_name);
+ SLOGV("removing %s\n", path);
+ rmdir(path);
+ }
+ }
+}
+
+void removeAllProcessGroups()
+{
+ SLOGV("removeAllProcessGroups()");
+ DIR *root = opendir(PROCESSGROUP_CGROUP_PATH);
+ if (root == NULL) {
+ SLOGE("failed to open %s: %s", PROCESSGROUP_CGROUP_PATH, strerror(errno));
+ }
+ if (root != NULL) {
+ struct dirent cur;
+ struct dirent *dir;
+ while ((readdir_r(root, &cur, &dir) == 0) && dir) {
+ 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))) {
+ continue;
+ }
+
+ snprintf(path, sizeof(path), "%s/%s", PROCESSGROUP_CGROUP_PATH, dir->d_name);
+ removeUidProcessGroups(path);
+ SLOGV("removing %s\n", path);
+ rmdir(path);
+ }
+ }
+}
+
+static int killProcessGroupOnce(uid_t uid, int initialPid, int signal)
+{
+ int processes = 0;
+ struct ctx ctx;
+ pid_t pid;
+
+ ctx.initialized = false;
+
+ while ((pid = getOneAppProcess(uid, initialPid, &ctx)) >= 0) {
+ processes++;
+ SLOGV("sending processgroup kill to pid %d\n", pid);
+ int ret = kill(pid, signal);
+ if (ret == -1) {
+ SLOGV("failed to kill pid %d: %s", pid, strerror(errno));
+ }
+ }
+
+ if (ctx.initialized) {
+ close(ctx.fd);
+ }
+
+ return processes;
+}
+
+int killProcessGroup(uid_t uid, int initialPid, int signal)
+{
+ int processes;
+ int sleep_us = 100;
+
+ while ((processes = killProcessGroupOnce(uid, initialPid, signal)) > 0) {
+ SLOGV("killed %d processes for processgroup %d\n", processes, initialPid);
+ if (sleep_us < 128000) {
+ usleep(sleep_us);
+ sleep_us *= 2;
+ } else {
+ SLOGE("failed to kill %d processes for processgroup %d\n",
+ processes, initialPid);
+ break;
+ }
+ }
+
+ if (processes == 0) {
+ return removeProcessGroup(uid, initialPid);
+ } else {
+ return -1;
+ }
+}
+
+static int mkdirAndChown(const char *path, mode_t mode, uid_t uid, gid_t gid)
+{
+ int ret;
+
+ ret = mkdir(path, 0750);
+ if (ret < 0 && errno != EEXIST) {
+ return -errno;
+ }
+
+ ret = chown(path, AID_SYSTEM, AID_SYSTEM);
+ if (ret < 0) {
+ ret = -errno;
+ rmdir(path);
+ return ret;
+ }
+
+ return 0;
+}
+
+int createProcessGroup(uid_t uid, int initialPid)
+{
+ char path[PROCESSGROUP_MAX_PATH_LEN] = {0};
+ int ret;
+
+ convertUidToPath(path, sizeof(path), uid);
+
+ ret = mkdirAndChown(path, 0750, AID_SYSTEM, AID_SYSTEM);
+ if (ret < 0) {
+ SLOGE("failed to make and chown %s: %s", path, strerror(-ret));
+ return ret;
+ }
+
+ convertUidPidToPath(path, sizeof(path), uid, initialPid);
+
+ ret = mkdirAndChown(path, 0750, AID_SYSTEM, AID_SYSTEM);
+ if (ret < 0) {
+ SLOGE("failed to make and chown %s: %s", path, strerror(-ret));
+ return ret;
+ }
+
+ strlcat(path, PROCESSGROUP_CGROUP_PROCS_FILE, sizeof(path));
+
+ int fd = open(path, O_WRONLY);
+ if (fd < 0) {
+ ret = -errno;
+ SLOGE("failed to open %s: %s", path, strerror(errno));
+ return ret;
+ }
+
+ char pid[PROCESSGROUP_MAX_PID_LEN + 1] = {0};
+ int len = snprintf(pid, sizeof(pid), "%d", initialPid);
+
+ ret = write(fd, pid, len);
+ if (ret < 0) {
+ ret = -errno;
+ SLOGE("failed to write '%s' to %s: %s", pid, path, strerror(errno));
+ } else {
+ ret = 0;
+ }
+
+ close(fd);
+ return ret;
+}
+