diff options
Diffstat (limited to 'tools/testing/selftests/bpf/cgroup_helpers.c')
| -rw-r--r-- | tools/testing/selftests/bpf/cgroup_helpers.c | 361 |
1 files changed, 311 insertions, 50 deletions
diff --git a/tools/testing/selftests/bpf/cgroup_helpers.c b/tools/testing/selftests/bpf/cgroup_helpers.c index 0fb910df5387..e914cc45b766 100644 --- a/tools/testing/selftests/bpf/cgroup_helpers.c +++ b/tools/testing/selftests/bpf/cgroup_helpers.c @@ -12,62 +12,73 @@ #include <unistd.h> #include <ftw.h> - #include "cgroup_helpers.h" /* * To avoid relying on the system setup, when setup_cgroup_env is called - * we create a new mount namespace, and cgroup namespace. The cgroup2 - * root is mounted at CGROUP_MOUNT_PATH - * - * Unfortunately, most people don't have cgroupv2 enabled at this point in time. - * It's easier to create our own mount namespace and manage it ourselves. + * we create a new mount namespace, and cgroup namespace. The cgroupv2 + * root is mounted at CGROUP_MOUNT_PATH. Unfortunately, most people don't + * have cgroupv2 enabled at this point in time. It's easier to create our + * own mount namespace and manage it ourselves. We assume /mnt exists. * - * We assume /mnt exists. + * Related cgroupv1 helpers are named *classid*(), since we only use the + * net_cls controller for tagging net_cls.classid. We assume the default + * mount under /sys/fs/cgroup/net_cls, which should be the case for the + * vast majority of users. */ #define WALK_FD_LIMIT 16 + #define CGROUP_MOUNT_PATH "/mnt" +#define CGROUP_MOUNT_DFLT "/sys/fs/cgroup" +#define NETCLS_MOUNT_PATH CGROUP_MOUNT_DFLT "/net_cls" #define CGROUP_WORK_DIR "/cgroup-test-work-dir" + +#define format_cgroup_path_pid(buf, path, pid) \ + snprintf(buf, sizeof(buf), "%s%s%d%s", CGROUP_MOUNT_PATH, \ + CGROUP_WORK_DIR, pid, path) + #define format_cgroup_path(buf, path) \ - snprintf(buf, sizeof(buf), "%s%s%s", CGROUP_MOUNT_PATH, \ - CGROUP_WORK_DIR, path) + format_cgroup_path_pid(buf, path, getpid()) -/** - * enable_all_controllers() - Enable all available cgroup v2 controllers - * - * Enable all available cgroup v2 controllers in order to increase - * the code coverage. - * - * If successful, 0 is returned. - */ -static int enable_all_controllers(char *cgroup_path) +#define format_parent_cgroup_path(buf, path) \ + format_cgroup_path_pid(buf, path, getppid()) + +#define format_classid_path(buf) \ + snprintf(buf, sizeof(buf), "%s%s", NETCLS_MOUNT_PATH, \ + CGROUP_WORK_DIR) + +static int __enable_controllers(const char *cgroup_path, const char *controllers) { char path[PATH_MAX + 1]; - char buf[PATH_MAX]; + char enable[PATH_MAX + 1]; char *c, *c2; int fd, cfd; ssize_t len; - snprintf(path, sizeof(path), "%s/cgroup.controllers", cgroup_path); - fd = open(path, O_RDONLY); - if (fd < 0) { - log_err("Opening cgroup.controllers: %s", path); - return 1; - } - - len = read(fd, buf, sizeof(buf) - 1); - if (len < 0) { + /* If not controllers are passed, enable all available controllers */ + if (!controllers) { + snprintf(path, sizeof(path), "%s/cgroup.controllers", + cgroup_path); + fd = open(path, O_RDONLY); + if (fd < 0) { + log_err("Opening cgroup.controllers: %s", path); + return 1; + } + len = read(fd, enable, sizeof(enable) - 1); + if (len < 0) { + close(fd); + log_err("Reading cgroup.controllers: %s", path); + return 1; + } else if (len == 0) { /* No controllers to enable */ + close(fd); + return 0; + } + enable[len] = 0; close(fd); - log_err("Reading cgroup.controllers: %s", path); - return 1; + } else { + strncpy(enable, controllers, sizeof(enable)); } - buf[len] = 0; - close(fd); - - /* No controllers available? We're probably on cgroup v1. */ - if (len == 0) - return 0; snprintf(path, sizeof(path), "%s/cgroup.subtree_control", cgroup_path); cfd = open(path, O_RDWR); @@ -76,7 +87,7 @@ static int enable_all_controllers(char *cgroup_path) return 1; } - for (c = strtok_r(buf, " ", &c2); c; c = strtok_r(NULL, " ", &c2)) { + for (c = strtok_r(enable, " ", &c2); c; c = strtok_r(NULL, " ", &c2)) { if (dprintf(cfd, "+%s\n", c) <= 0) { log_err("Enabling controller %s: %s", c, path); close(cfd); @@ -88,6 +99,87 @@ static int enable_all_controllers(char *cgroup_path) } /** + * enable_controllers() - Enable cgroup v2 controllers + * @relative_path: The cgroup path, relative to the workdir + * @controllers: List of controllers to enable in cgroup.controllers format + * + * + * Enable given cgroup v2 controllers, if @controllers is NULL, enable all + * available controllers. + * + * If successful, 0 is returned. + */ +int enable_controllers(const char *relative_path, const char *controllers) +{ + char cgroup_path[PATH_MAX + 1]; + + format_cgroup_path(cgroup_path, relative_path); + return __enable_controllers(cgroup_path, controllers); +} + +static int __write_cgroup_file(const char *cgroup_path, const char *file, + const char *buf) +{ + char file_path[PATH_MAX + 1]; + int fd; + + snprintf(file_path, sizeof(file_path), "%s/%s", cgroup_path, file); + fd = open(file_path, O_RDWR); + if (fd < 0) { + log_err("Opening %s", file_path); + return 1; + } + + if (dprintf(fd, "%s", buf) <= 0) { + log_err("Writing to %s", file_path); + close(fd); + return 1; + } + close(fd); + return 0; +} + +/** + * write_cgroup_file() - Write to a cgroup file + * @relative_path: The cgroup path, relative to the workdir + * @file: The name of the file in cgroupfs to write to + * @buf: Buffer to write to the file + * + * Write to a file in the given cgroup's directory. + * + * If successful, 0 is returned. + */ +int write_cgroup_file(const char *relative_path, const char *file, + const char *buf) +{ + char cgroup_path[PATH_MAX - 24]; + + format_cgroup_path(cgroup_path, relative_path); + return __write_cgroup_file(cgroup_path, file, buf); +} + +/** + * write_cgroup_file_parent() - Write to a cgroup file in the parent process + * workdir + * @relative_path: The cgroup path, relative to the parent process workdir + * @file: The name of the file in cgroupfs to write to + * @buf: Buffer to write to the file + * + * Write to a file in the given cgroup's directory under the parent process + * workdir. + * + * If successful, 0 is returned. + */ +int write_cgroup_file_parent(const char *relative_path, const char *file, + const char *buf) +{ + char cgroup_path[PATH_MAX - 24]; + + format_parent_cgroup_path(cgroup_path, relative_path); + return __write_cgroup_file(cgroup_path, file, buf); +} + +/** * setup_cgroup_environment() - Setup the cgroup environment * * After calling this function, cleanup_cgroup_environment should be called @@ -125,7 +217,9 @@ int setup_cgroup_environment(void) return 1; } - if (enable_all_controllers(cgroup_workdir)) + /* Enable all available controllers to increase test coverage */ + if (__enable_controllers(CGROUP_MOUNT_PATH, NULL) || + __enable_controllers(cgroup_workdir, NULL)) return 1; return 0; @@ -139,8 +233,7 @@ static int nftwfunc(const char *filename, const struct stat *statptr, return 0; } - -static int join_cgroup_from_top(char *cgroup_path) +static int join_cgroup_from_top(const char *cgroup_path) { char cgroup_procs_path[PATH_MAX + 1]; pid_t pid = getpid(); @@ -166,7 +259,7 @@ static int join_cgroup_from_top(char *cgroup_path) /** * join_cgroup() - Join a cgroup - * @path: The cgroup path, relative to the workdir, to join + * @relative_path: The cgroup path, relative to the workdir, to join * * This function expects a cgroup to already be created, relative to the cgroup * work dir, and it joins it. For example, passing "/my-cgroup" as the path @@ -175,11 +268,27 @@ static int join_cgroup_from_top(char *cgroup_path) * * On success, it returns 0, otherwise on failure it returns 1. */ -int join_cgroup(const char *path) +int join_cgroup(const char *relative_path) { char cgroup_path[PATH_MAX + 1]; - format_cgroup_path(cgroup_path, path); + format_cgroup_path(cgroup_path, relative_path); + return join_cgroup_from_top(cgroup_path); +} + +/** + * join_parent_cgroup() - Join a cgroup in the parent process workdir + * @relative_path: The cgroup path, relative to parent process workdir, to join + * + * See join_cgroup(). + * + * On success, it returns 0, otherwise on failure it returns 1. + */ +int join_parent_cgroup(const char *relative_path) +{ + char cgroup_path[PATH_MAX + 1]; + + format_parent_cgroup_path(cgroup_path, relative_path); return join_cgroup_from_top(cgroup_path); } @@ -206,8 +315,26 @@ void cleanup_cgroup_environment(void) } /** + * get_root_cgroup() - Get the FD of the root cgroup + * + * On success, it returns the file descriptor. On failure, it returns -1. + * If there is a failure, it prints the error to stderr. + */ +int get_root_cgroup(void) +{ + int fd; + + fd = open(CGROUP_MOUNT_PATH, O_RDONLY); + if (fd < 0) { + log_err("Opening root cgroup"); + return -1; + } + return fd; +} + +/** * create_and_get_cgroup() - Create a cgroup, relative to workdir, and get the FD - * @path: The cgroup path, relative to the workdir, to join + * @relative_path: The cgroup path, relative to the workdir, to join * * This function creates a cgroup under the top level workdir and returns the * file descriptor. It is idempotent. @@ -215,14 +342,14 @@ void cleanup_cgroup_environment(void) * On success, it returns the file descriptor. On failure it returns -1. * If there is a failure, it prints the error to stderr. */ -int create_and_get_cgroup(const char *path) +int create_and_get_cgroup(const char *relative_path) { char cgroup_path[PATH_MAX + 1]; int fd; - format_cgroup_path(cgroup_path, path); + format_cgroup_path(cgroup_path, relative_path); if (mkdir(cgroup_path, 0777) && errno != EEXIST) { - log_err("mkdiring cgroup %s .. %s", path, cgroup_path); + log_err("mkdiring cgroup %s .. %s", relative_path, cgroup_path); return -1; } @@ -237,13 +364,13 @@ int create_and_get_cgroup(const char *path) /** * get_cgroup_id() - Get cgroup id for a particular cgroup path - * @path: The cgroup path, relative to the workdir, to join + * @relative_path: The cgroup path, relative to the workdir, to join * * On success, it returns the cgroup id. On failure it returns 0, * which is an invalid cgroup id. * If there is a failure, it prints the error to stderr. */ -unsigned long long get_cgroup_id(const char *path) +unsigned long long get_cgroup_id(const char *relative_path) { int dirfd, err, flags, mount_id, fhsize; union { @@ -254,7 +381,7 @@ unsigned long long get_cgroup_id(const char *path) struct file_handle *fhp, *fhp2; unsigned long long ret = 0; - format_cgroup_path(cgroup_workdir, path); + format_cgroup_path(cgroup_workdir, relative_path); dirfd = AT_FDCWD; flags = 0; @@ -290,3 +417,137 @@ free_mem: free(fhp); return ret; } + +int cgroup_setup_and_join(const char *path) { + int cg_fd; + + if (setup_cgroup_environment()) { + fprintf(stderr, "Failed to setup cgroup environment\n"); + return -EINVAL; + } + + cg_fd = create_and_get_cgroup(path); + if (cg_fd < 0) { + fprintf(stderr, "Failed to create test cgroup\n"); + cleanup_cgroup_environment(); + return cg_fd; + } + + if (join_cgroup(path)) { + fprintf(stderr, "Failed to join cgroup\n"); + cleanup_cgroup_environment(); + return -EINVAL; + } + return cg_fd; +} + +/** + * setup_classid_environment() - Setup the cgroupv1 net_cls environment + * + * After calling this function, cleanup_classid_environment should be called + * once testing is complete. + * + * This function will print an error to stderr and return 1 if it is unable + * to setup the cgroup environment. If setup is successful, 0 is returned. + */ +int setup_classid_environment(void) +{ + char cgroup_workdir[PATH_MAX + 1]; + + format_classid_path(cgroup_workdir); + + if (mount("tmpfs", CGROUP_MOUNT_DFLT, "tmpfs", 0, NULL) && + errno != EBUSY) { + log_err("mount cgroup base"); + return 1; + } + + if (mkdir(NETCLS_MOUNT_PATH, 0777) && errno != EEXIST) { + log_err("mkdir cgroup net_cls"); + return 1; + } + + if (mount("net_cls", NETCLS_MOUNT_PATH, "cgroup", 0, "net_cls") && + errno != EBUSY) { + log_err("mount cgroup net_cls"); + return 1; + } + + cleanup_classid_environment(); + + if (mkdir(cgroup_workdir, 0777) && errno != EEXIST) { + log_err("mkdir cgroup work dir"); + return 1; + } + + return 0; +} + +/** + * set_classid() - Set a cgroupv1 net_cls classid + * @id: the numeric classid + * + * Writes the passed classid into the cgroup work dir's net_cls.classid + * file in order to later on trigger socket tagging. + * + * On success, it returns 0, otherwise on failure it returns 1. If there + * is a failure, it prints the error to stderr. + */ +int set_classid(unsigned int id) +{ + char cgroup_workdir[PATH_MAX - 42]; + char cgroup_classid_path[PATH_MAX + 1]; + int fd, rc = 0; + + format_classid_path(cgroup_workdir); + snprintf(cgroup_classid_path, sizeof(cgroup_classid_path), + "%s/net_cls.classid", cgroup_workdir); + + fd = open(cgroup_classid_path, O_WRONLY); + if (fd < 0) { + log_err("Opening cgroup classid: %s", cgroup_classid_path); + return 1; + } + + if (dprintf(fd, "%u\n", id) < 0) { + log_err("Setting cgroup classid"); + rc = 1; + } + + close(fd); + return rc; +} + +/** + * join_classid() - Join a cgroupv1 net_cls classid + * + * This function expects the cgroup work dir to be already created, as we + * join it here. This causes the process sockets to be tagged with the given + * net_cls classid. + * + * On success, it returns 0, otherwise on failure it returns 1. + */ +int join_classid(void) +{ + char cgroup_workdir[PATH_MAX + 1]; + + format_classid_path(cgroup_workdir); + return join_cgroup_from_top(cgroup_workdir); +} + +/** + * cleanup_classid_environment() - Cleanup the cgroupv1 net_cls environment + * + * At call time, it moves the calling process to the root cgroup, and then + * runs the deletion process. + * + * On failure, it will print an error to stderr, and try to continue. + */ +void cleanup_classid_environment(void) +{ + char cgroup_workdir[PATH_MAX + 1]; + + format_classid_path(cgroup_workdir); + join_cgroup_from_top(NETCLS_MOUNT_PATH); + nftw(cgroup_workdir, nftwfunc, WALK_FD_LIMIT, FTW_DEPTH | FTW_MOUNT); +} |