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, 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 four commits add the new functionality, the fifth adds corresponding self-tests, and the last two are small additional fixes. v1 -> v2: * rewrite the add_fd_from_fd_array() function (Eduard) * a few cleanups in selftests (Eduard) v2 -> v3: * various renamings (Alexey) * "0 is not special" (Alexey, Andrii) * do not alloc memory on fd_array init (Alexey) * 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 (Alexey) * remove extra code (Alexey) Anton Protopopov (7): bpf: add a __btf_get_by_fd helper bpf: move map/prog compatibility checks 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 bpf: fix potential error return selftest/bpf: replace magic constants by macros include/linux/bpf.h | 17 + include/linux/btf.h | 2 + include/uapi/linux/bpf.h | 10 + kernel/bpf/btf.c | 13 +- kernel/bpf/core.c | 6 +- kernel/bpf/syscall.c | 2 +- kernel/bpf/verifier.c | 215 ++++++----- tools/include/uapi/linux/bpf.h | 10 + tools/lib/bpf/bpf.c | 5 +- tools/lib/bpf/bpf.h | 5 +- tools/lib/bpf/features.c | 2 +- .../selftests/bpf/prog_tests/fd_array.c | 340 ++++++++++++++++++ tools/testing/selftests/bpf/progs/syscall.c | 6 +- 13 files changed, 535 insertions(+), 98 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/fd_array.c -- 2.34.1
