diff options
Diffstat (limited to 'kernel/bpf/preload/iterators/iterators.c')
-rw-r--r-- | kernel/bpf/preload/iterators/iterators.c | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/kernel/bpf/preload/iterators/iterators.c b/kernel/bpf/preload/iterators/iterators.c new file mode 100644 index 000000000..b7ff87939 --- /dev/null +++ b/kernel/bpf/preload/iterators/iterators.c @@ -0,0 +1,94 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2020 Facebook */ +#include <argp.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <fcntl.h> +#include <sys/resource.h> +#include <bpf/libbpf.h> +#include <bpf/bpf.h> +#include <sys/mount.h> +#include "iterators.skel.h" +#include "bpf_preload_common.h" + +int to_kernel = -1; +int from_kernel = 0; + +static int send_link_to_kernel(struct bpf_link *link, const char *link_name) +{ + struct bpf_preload_info obj = {}; + struct bpf_link_info info = {}; + __u32 info_len = sizeof(info); + int err; + + err = bpf_obj_get_info_by_fd(bpf_link__fd(link), &info, &info_len); + if (err) + return err; + obj.link_id = info.id; + if (strlen(link_name) >= sizeof(obj.link_name)) + return -E2BIG; + strcpy(obj.link_name, link_name); + if (write(to_kernel, &obj, sizeof(obj)) != sizeof(obj)) + return -EPIPE; + return 0; +} + +int main(int argc, char **argv) +{ + struct rlimit rlim = { RLIM_INFINITY, RLIM_INFINITY }; + struct iterators_bpf *skel; + int err, magic; + int debug_fd; + + debug_fd = open("/dev/console", O_WRONLY | O_NOCTTY | O_CLOEXEC); + if (debug_fd < 0) + return 1; + to_kernel = dup(1); + close(1); + dup(debug_fd); + /* now stdin and stderr point to /dev/console */ + + read(from_kernel, &magic, sizeof(magic)); + if (magic != BPF_PRELOAD_START) { + printf("bad start magic %d\n", magic); + return 1; + } + setrlimit(RLIMIT_MEMLOCK, &rlim); + /* libbpf opens BPF object and loads it into the kernel */ + skel = iterators_bpf__open_and_load(); + if (!skel) { + /* iterators.skel.h is little endian. + * libbpf doesn't support automatic little->big conversion + * of BPF bytecode yet. + * The program load will fail in such case. + */ + printf("Failed load could be due to wrong endianness\n"); + return 1; + } + err = iterators_bpf__attach(skel); + if (err) + goto cleanup; + + /* send two bpf_link IDs with names to the kernel */ + err = send_link_to_kernel(skel->links.dump_bpf_map, "maps.debug"); + if (err) + goto cleanup; + err = send_link_to_kernel(skel->links.dump_bpf_prog, "progs.debug"); + if (err) + goto cleanup; + + /* The kernel will proceed with pinnging the links in bpffs. + * UMD will wait on read from pipe. + */ + read(from_kernel, &magic, sizeof(magic)); + if (magic != BPF_PRELOAD_END) { + printf("bad final magic %d\n", magic); + err = -EINVAL; + } +cleanup: + iterators_bpf__destroy(skel); + + return err != 0; +} |