Files
cgproxy/cgattach.cpp
2020-05-14 13:57:39 +08:00

101 lines
2.7 KiB
C++

#include <errno.h>
#include <fstream>
#include <iostream>
#include <regex>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
using namespace std;
#define error(...) {fprintf(stderr, __VA_ARGS__);fprintf(stderr, "\n");}
#define debug(...) {fprintf(stdout, __VA_ARGS__);fprintf(stdout, "\n");}
void print_usage() { fprintf(stdout, "usage: cgattach <pid> <cgroup>\n"); }
bool exist(string path) {
struct stat st;
if (stat(path.c_str(), &st) != -1) {
return S_ISDIR(st.st_mode);
}
return false;
}
bool validate(string pid, string cgroup) {
bool pid_v = regex_match(pid, regex("^[0-9]+$"));
bool cg_v = regex_match(cgroup, regex("^\\/[a-zA-Z0-9\\-_./@]*$"));
if (pid_v && cg_v)
return true;
error("paramater validate error");
print_usage();
exit(EXIT_FAILURE);
}
string get_cgroup2_mount_point(){
char cgroup2_mount_point[100]="";
FILE* fp = popen("findmnt -t cgroup2 -n -o TARGET", "r");
int count=fscanf(fp,"%s",&cgroup2_mount_point);
fclose(fp);
if (count=0){
error("cgroup2 not supported");
exit(EXIT_FAILURE);
}
return cgroup2_mount_point;
}
int main(int argc, char *argv[]) {
int flag=setuid(0);
if (flag!=0) {
perror("cgattach setuid");
exit(EXIT_FAILURE);
}
if (argc != 3) {
error("only need 2 paramaters");
print_usage();
exit(EXIT_FAILURE);
}
string pid = string(argv[1]);
string cgroup_target = string(argv[2]);
validate(pid, cgroup_target);
// string cgroup_mount_point = "/sys/fs/cgroup";
string cgroup_mount_point = get_cgroup2_mount_point();
string cgroup_target_path = cgroup_mount_point + cgroup_target;
string cgroup_target_procs = cgroup_target_path + "/cgroup.procs";
// check if exist, we will create it if not exist
if (!exist(cgroup_target_path)) {
if (mkdir(cgroup_target_path.c_str(),
S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH) == 0) {
debug("created cgroup %s success", cgroup_target.c_str());
} else {
error("created cgroup %s failed, errno %d", cgroup_target.c_str(), errno);
exit(EXIT_FAILURE);
}
// error("cgroup %s not exist",cgroup_target.c_str());
// exit(EXIT_FAILURE);
}
// put pid to target cgroup
ofstream procs(cgroup_target_procs, ofstream::app);
if (!procs.is_open()) {
error("open file %s failed", cgroup_target_procs.c_str());
exit(EXIT_FAILURE);
}
procs << pid.c_str() << endl;
procs.close();
// maybe there some write error, for example process pid may not exist
if (!procs) {
error("write %s to %s failed, maybe process %s not exist",
pid.c_str(), cgroup_target_procs.c_str(), pid.c_str());
exit(EXIT_FAILURE);
}
return EXIT_SUCCESS;
}