This patch modifies test_current_task_under_cgroup_user. The test has several helpers around creating a temporary environment for cgroup testing, and moving the current task around cgroups. This set of helpers can then be used in other tests. Signed-off-by: Sargun Dhillon <sargun@sargun.me> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>tirimbino
Sargun Dhillon
8 years ago
committed by
David S. Miller
parent
69a9d09b22
commit
1a922fee66
@ -0,0 +1,177 @@ |
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#define _GNU_SOURCE |
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#include <sched.h> |
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#include <sys/mount.h> |
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#include <sys/stat.h> |
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#include <sys/types.h> |
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#include <linux/limits.h> |
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#include <stdio.h> |
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#include <linux/sched.h> |
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#include <fcntl.h> |
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#include <unistd.h> |
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#include <ftw.h> |
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#include "cgroup_helpers.h" |
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/*
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* To avoid relying on the system setup, when setup_cgroup_env is called |
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* we create a new mount namespace, and cgroup namespace. The cgroup2 |
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* root is mounted at CGROUP_MOUNT_PATH |
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* |
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* Unfortunately, most people don't have cgroupv2 enabled at this point in time. |
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* It's easier to create our own mount namespace and manage it ourselves. |
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* |
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* We assume /mnt exists. |
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*/ |
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#define WALK_FD_LIMIT 16 |
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#define CGROUP_MOUNT_PATH "/mnt" |
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#define CGROUP_WORK_DIR "/cgroup-test-work-dir" |
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#define format_cgroup_path(buf, path) \ |
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snprintf(buf, sizeof(buf), "%s%s%s", CGROUP_MOUNT_PATH, \
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CGROUP_WORK_DIR, path) |
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/**
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* setup_cgroup_environment() - Setup the cgroup environment |
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* |
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* After calling this function, cleanup_cgroup_environment should be called |
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* once testing is complete. |
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* |
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* This function will print an error to stderr and return 1 if it is unable |
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* to setup the cgroup environment. If setup is successful, 0 is returned. |
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*/ |
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int setup_cgroup_environment(void) |
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{ |
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char cgroup_workdir[PATH_MAX + 1]; |
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format_cgroup_path(cgroup_workdir, ""); |
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if (unshare(CLONE_NEWNS)) { |
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log_err("unshare"); |
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return 1; |
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} |
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if (mount("none", "/", NULL, MS_REC | MS_PRIVATE, NULL)) { |
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log_err("mount fakeroot"); |
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return 1; |
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} |
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if (mount("none", CGROUP_MOUNT_PATH, "cgroup2", 0, NULL)) { |
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log_err("mount cgroup2"); |
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return 1; |
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} |
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/* Cleanup existing failed runs, now that the environment is setup */ |
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cleanup_cgroup_environment(); |
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if (mkdir(cgroup_workdir, 0777) && errno != EEXIST) { |
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log_err("mkdir cgroup work dir"); |
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return 1; |
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} |
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return 0; |
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} |
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static int nftwfunc(const char *filename, const struct stat *statptr, |
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int fileflags, struct FTW *pfwt) |
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{ |
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if ((fileflags & FTW_D) && rmdir(filename)) |
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log_err("Removing cgroup: %s", filename); |
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return 0; |
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} |
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static int join_cgroup_from_top(char *cgroup_path) |
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{ |
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char cgroup_procs_path[PATH_MAX + 1]; |
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pid_t pid = getpid(); |
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int fd, rc = 0; |
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snprintf(cgroup_procs_path, sizeof(cgroup_procs_path), |
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"%s/cgroup.procs", cgroup_path); |
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fd = open(cgroup_procs_path, O_WRONLY); |
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if (fd < 0) { |
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log_err("Opening Cgroup Procs: %s", cgroup_procs_path); |
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return 1; |
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} |
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if (dprintf(fd, "%d\n", pid) < 0) { |
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log_err("Joining Cgroup"); |
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rc = 1; |
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} |
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close(fd); |
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return rc; |
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} |
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/**
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* join_cgroup() - Join a cgroup |
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* @path: The cgroup path, relative to the workdir, to join |
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* |
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* This function expects a cgroup to already be created, relative to the cgroup |
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* work dir, and it joins it. For example, passing "/my-cgroup" as the path |
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* would actually put the calling process into the cgroup |
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* "/cgroup-test-work-dir/my-cgroup" |
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* |
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* On success, it returns 0, otherwise on failure it returns 1. |
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*/ |
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int join_cgroup(char *path) |
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{ |
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char cgroup_path[PATH_MAX + 1]; |
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format_cgroup_path(cgroup_path, path); |
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return join_cgroup_from_top(cgroup_path); |
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} |
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/**
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* cleanup_cgroup_environment() - Cleanup Cgroup Testing Environment |
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* |
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* This is an idempotent function to delete all temporary cgroups that |
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* have been created during the test, including the cgroup testing work |
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* directory. |
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* |
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* At call time, it moves the calling process to the root cgroup, and then |
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* runs the deletion process. It is idempotent, and should not fail, unless |
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* a process is lingering. |
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* |
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* On failure, it will print an error to stderr, and try to continue. |
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*/ |
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void cleanup_cgroup_environment(void) |
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{ |
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char cgroup_workdir[PATH_MAX + 1]; |
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format_cgroup_path(cgroup_workdir, ""); |
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join_cgroup_from_top(CGROUP_MOUNT_PATH); |
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nftw(cgroup_workdir, nftwfunc, WALK_FD_LIMIT, FTW_DEPTH | FTW_MOUNT); |
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} |
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/**
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* create_and_get_cgroup() - Create a cgroup, relative to workdir, and get the FD |
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* @path: The cgroup path, relative to the workdir, to join |
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* |
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* This function creates a cgroup under the top level workdir and returns the |
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* file descriptor. It is idempotent. |
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* |
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* On success, it returns the file descriptor. On failure it returns 0. |
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* If there is a failure, it prints the error to stderr. |
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*/ |
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int create_and_get_cgroup(char *path) |
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{ |
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char cgroup_path[PATH_MAX + 1]; |
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int fd; |
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format_cgroup_path(cgroup_path, path); |
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if (mkdir(cgroup_path, 0777) && errno != EEXIST) { |
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log_err("mkdiring cgroup"); |
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return 0; |
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} |
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fd = open(cgroup_path, O_RDONLY); |
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if (fd < 0) { |
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log_err("Opening Cgroup"); |
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return 0; |
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} |
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return fd; |
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} |
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@ -0,0 +1,16 @@ |
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#ifndef __CGROUP_HELPERS_H |
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#define __CGROUP_HELPERS_H |
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#include <errno.h> |
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#include <string.h> |
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#define clean_errno() (errno == 0 ? "None" : strerror(errno)) |
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#define log_err(MSG, ...) fprintf(stderr, "(%s:%d: errno: %s) " MSG "\n", \ |
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__FILE__, __LINE__, clean_errno(), ##__VA_ARGS__) |
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int create_and_get_cgroup(char *path); |
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int join_cgroup(char *path); |
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int setup_cgroup_environment(void); |
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void cleanup_cgroup_environment(void); |
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#endif |
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