Nicky Chorley <ndchorley@gmail.com>于2022年8月9日 周二20:31写道：
Hi folks,
I wrote a small program to start a new process (a shell), create a cgroup and add the process to it. This all works fine - the process ID of the shell ends up in the cgroup.procs file and when my program exits, cgroup.procs ends up empty as expected. If I try and remove the cgroup directory, though, I get a load of "Operation not permitted" errors and I'm not sure why. I'm running on openSUSE (kernel 5.3.18) with cgroups v2.
My program looks like:
#define _GNU_SOURCE #include <sched.h> #include <signal.h> #include <stdio.h> #include <stdlib.h> #include <sys/stat.h> #include <sys/wait.h> #include <unistd.h>
int startShell(void *argument) { char* arguments[] = {"bash", NULL}; char* environment[] = {NULL}; execve("/bin/bash", arguments, environment);
return 0; }
int main() { mkdir( "/sys/fs/cgroup/my_group", S_IRWXO | S_IRGRP | S_IROTH );
int stackSizeBytes = 65536; char *stackStart = malloc(stackSizeBytes); char *stackEnd = stackStart + stackSizeBytes;
pid_t childPid = clone( startShell, stackEnd, SIGCHLD, NULL );
FILE* procsFile = fopen( "/sys/fs/cgroup/my_group/cgroup.procs", "w" );
fprintf(procsFile, "%d\n", childPid); fclose(procsFile);
waitpid(childPid, NULL, 0);
return 0; }
and output looks like:
$ su -c ./run Password:
# echo $$ 4382 # cat /sys/fs/cgroup/my_group/cgroup.procs 4382 4522 # exit $ cat /sys/fs/cgroup/my_group/cgroup.procs $ su -c "rm -rf /sys/fs/cgroup/my_group"
You have to use rmdir to remove
Password: rm: cannot remove '/sys/fs/cgroup/my_group/cgroup.events': Operation not permitted rm: cannot remove '/sys/fs/cgroup/my_group/memory.events': Operation not permitted ... other lines omitted for brevity
Could someone please help me understand what's going on here?
Thanks!
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