Add a new attribute to the bpf(BPF_PROG_LOAD) system call. If this new attribute is non-zero, then the fd_array is considered to be a continuous array of the fd_array_cnt length and to contain only proper map file descriptors or btf file descriptors. This change allows maps (and btfs), which aren't referenced directly by a BPF program, to be bound to the program _and_ also to be present during the program verification (so BPF_PROG_BIND_MAP is not enough for this use case). The primary reason for this change is that it is a prerequisite for adding "instruction set" maps, which are both non-referenced by the program and must be present during the program verification. The first five commits add the new functionality, the sixth adds corresponding self-tests, and the last one is a small additional fix. v1 -> v2: * rewrite the add_fd_from_fd_array() function (Eduard) * a few cleanups in selftests (Eduard) v2 -> v3: * various renamings (Alexei) * "0 is not special" (Alexei, Andrii) * do not alloc memory on fd_array init (Alexei) * fix leaking maps for error path (Hou Tao) * use libbpf helpers vs. raw syscalls (Andrii) * add comments on __btf_get_by_fd/__bpf_map_get (Alexei) * remove extra code (Alexei) v3 -> v4: * simplify error path when parsing fd_array * libbpf: pass fd_array_cnt only in prog_load (Alexei) * selftests patch contained extra code (Alexei) * renames, fix comments (Alexei) v4 -> v5: * Add btfs to env->used_btfs (Andrii) * Fix an integer overflow (Andrii) * A set of cleanups for selftests (Andrii) Anton Protopopov (7): bpf: add a __btf_get_by_fd helper bpf: move map/prog compatibility checks bpf: refactor check_pseudo_btf_id bpf: add fd_array_cnt attribute for prog_load libbpf: prog load: allow to use fd_array_cnt selftests/bpf: Add tests for fd_array_cnt selftest/bpf: replace magic constants by macros include/linux/bpf.h | 17 + include/uapi/linux/bpf.h | 10 + kernel/bpf/btf.c | 11 +- kernel/bpf/syscall.c | 2 +- kernel/bpf/verifier.c | 333 ++++++++----- tools/include/uapi/linux/bpf.h | 10 + tools/lib/bpf/bpf.c | 3 +- tools/lib/bpf/bpf.h | 5 +- .../selftests/bpf/prog_tests/fd_array.c | 441 ++++++++++++++++++ tools/testing/selftests/bpf/progs/syscall.c | 6 +- 10 files changed, 701 insertions(+), 137 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/fd_array.c -- 2.34.1
