diff options
| -rw-r--r-- | MAINTAINERS | 1 | ||||
| -rw-r--r-- | samples/hid/.gitignore | 7 | ||||
| -rw-r--r-- | samples/hid/Makefile | 246 | ||||
| -rw-r--r-- | samples/hid/Makefile.target | 75 | ||||
| -rw-r--r-- | samples/hid/hid_bpf_attach.bpf.c | 18 | ||||
| -rw-r--r-- | samples/hid/hid_bpf_attach.h | 14 | ||||
| -rw-r--r-- | samples/hid/hid_bpf_helpers.h | 19 | ||||
| -rw-r--r-- | samples/hid/hid_mouse.bpf.c | 112 | ||||
| -rw-r--r-- | samples/hid/hid_mouse.c | 155 |
9 files changed, 647 insertions, 0 deletions
diff --git a/MAINTAINERS b/MAINTAINERS index 81eb9abbc17a..76d8185c408e 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -9100,6 +9100,7 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid.git F: drivers/hid/ F: include/linux/hid* F: include/uapi/linux/hid* +F: samples/hid/ F: tools/testing/selftests/hid/ HID LOGITECH DRIVERS diff --git a/samples/hid/.gitignore b/samples/hid/.gitignore new file mode 100644 index 000000000000..8cb45592e29a --- /dev/null +++ b/samples/hid/.gitignore @@ -0,0 +1,7 @@ +# SPDX-License-Identifier: GPL-2.0-only +hid_mouse +*.out +*.skel.h +/vmlinux.h +/bpftool/ +/libbpf/ diff --git a/samples/hid/Makefile b/samples/hid/Makefile new file mode 100644 index 000000000000..8fe6ccfc5f29 --- /dev/null +++ b/samples/hid/Makefile @@ -0,0 +1,246 @@ +# SPDX-License-Identifier: GPL-2.0 + +HID_SAMPLES_PATH ?= $(abspath $(srctree)/$(src)) +TOOLS_PATH := $(HID_SAMPLES_PATH)/../../tools + +pound := \# + +# List of programs to build +tprogs-y += hid_mouse + +# Libbpf dependencies +LIBBPF_SRC = $(TOOLS_PATH)/lib/bpf +LIBBPF_OUTPUT = $(abspath $(HID_SAMPLES_PATH))/libbpf +LIBBPF_DESTDIR = $(LIBBPF_OUTPUT) +LIBBPF_INCLUDE = $(LIBBPF_DESTDIR)/include +LIBBPF = $(LIBBPF_OUTPUT)/libbpf.a + +EXTRA_HEADERS := hid_bpf_attach.h +EXTRA_BPF_HEADERS := hid_bpf_helpers.h + +hid_mouse-objs := hid_mouse.o + +# Tell kbuild to always build the programs +always-y := $(tprogs-y) + +ifeq ($(ARCH), arm) +# Strip all except -D__LINUX_ARM_ARCH__ option needed to handle linux +# headers when arm instruction set identification is requested. +ARM_ARCH_SELECTOR := $(filter -D__LINUX_ARM_ARCH__%, $(KBUILD_CFLAGS)) +BPF_EXTRA_CFLAGS := $(ARM_ARCH_SELECTOR) +TPROGS_CFLAGS += $(ARM_ARCH_SELECTOR) +endif + +ifeq ($(ARCH), mips) +TPROGS_CFLAGS += -D__SANE_USERSPACE_TYPES__ +ifdef CONFIG_MACH_LOONGSON64 +BPF_EXTRA_CFLAGS += -I$(srctree)/arch/mips/include/asm/mach-loongson64 +BPF_EXTRA_CFLAGS += -I$(srctree)/arch/mips/include/asm/mach-generic +endif +endif + +TPROGS_CFLAGS += -Wall -O2 +TPROGS_CFLAGS += -Wmissing-prototypes +TPROGS_CFLAGS += -Wstrict-prototypes + +TPROGS_CFLAGS += -I$(objtree)/usr/include +TPROGS_CFLAGS += -I$(LIBBPF_INCLUDE) +TPROGS_CFLAGS += -I$(srctree)/tools/include + +ifdef SYSROOT +TPROGS_CFLAGS += --sysroot=$(SYSROOT) +TPROGS_LDFLAGS := -L$(SYSROOT)/usr/lib +endif + +TPROGS_LDLIBS += $(LIBBPF) -lelf -lz + +# Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline: +# make M=samples/bpf LLC=~/git/llvm-project/llvm/build/bin/llc CLANG=~/git/llvm-project/llvm/build/bin/clang +LLC ?= llc +CLANG ?= clang +OPT ?= opt +LLVM_DIS ?= llvm-dis +LLVM_OBJCOPY ?= llvm-objcopy +LLVM_READELF ?= llvm-readelf +BTF_PAHOLE ?= pahole + +# Detect that we're cross compiling and use the cross compiler +ifdef CROSS_COMPILE +CLANG_ARCH_ARGS = --target=$(notdir $(CROSS_COMPILE:%-=%)) +endif + +# Don't evaluate probes and warnings if we need to run make recursively +ifneq ($(src),) +HDR_PROBE := $(shell printf "$(pound)include <linux/types.h>\n struct list_head { int a; }; int main() { return 0; }" | \ + $(CC) $(TPROGS_CFLAGS) $(TPROGS_LDFLAGS) -x c - \ + -o /dev/null 2>/dev/null && echo okay) + +ifeq ($(HDR_PROBE),) +$(warning WARNING: Detected possible issues with include path.) +$(warning WARNING: Please install kernel headers locally (make headers_install).) +endif + +BTF_LLC_PROBE := $(shell $(LLC) -march=bpf -mattr=help 2>&1 | grep dwarfris) +BTF_PAHOLE_PROBE := $(shell $(BTF_PAHOLE) --help 2>&1 | grep BTF) +BTF_OBJCOPY_PROBE := $(shell $(LLVM_OBJCOPY) --help 2>&1 | grep -i 'usage.*llvm') +BTF_LLVM_PROBE := $(shell echo "int main() { return 0; }" | \ + $(CLANG) -target bpf -O2 -g -c -x c - -o ./llvm_btf_verify.o; \ + $(LLVM_READELF) -S ./llvm_btf_verify.o | grep BTF; \ + /bin/rm -f ./llvm_btf_verify.o) + +BPF_EXTRA_CFLAGS += -fno-stack-protector +ifneq ($(BTF_LLVM_PROBE),) + BPF_EXTRA_CFLAGS += -g +else +ifneq ($(and $(BTF_LLC_PROBE),$(BTF_PAHOLE_PROBE),$(BTF_OBJCOPY_PROBE)),) + BPF_EXTRA_CFLAGS += -g + LLC_FLAGS += -mattr=dwarfris + DWARF2BTF = y +endif +endif +endif + +# Trick to allow make to be run from this directory +all: + $(MAKE) -C ../../ M=$(CURDIR) HID_SAMPLES_PATH=$(CURDIR) + +clean: + $(MAKE) -C ../../ M=$(CURDIR) clean + @find $(CURDIR) -type f -name '*~' -delete + @$(RM) -r $(CURDIR)/libbpf $(CURDIR)/bpftool + +$(LIBBPF): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(LIBBPF_OUTPUT) +# Fix up variables inherited from Kbuild that tools/ build system won't like + $(MAKE) -C $(LIBBPF_SRC) RM='rm -rf' EXTRA_CFLAGS="$(TPROGS_CFLAGS)" \ + LDFLAGS=$(TPROGS_LDFLAGS) srctree=$(HID_SAMPLES_PATH)/../../ \ + O= OUTPUT=$(LIBBPF_OUTPUT)/ DESTDIR=$(LIBBPF_DESTDIR) prefix= \ + $@ install_headers + +BPFTOOLDIR := $(TOOLS_PATH)/bpf/bpftool +BPFTOOL_OUTPUT := $(abspath $(HID_SAMPLES_PATH))/bpftool +BPFTOOL := $(BPFTOOL_OUTPUT)/bootstrap/bpftool +$(BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile) | $(BPFTOOL_OUTPUT) + $(MAKE) -C $(BPFTOOLDIR) srctree=$(HID_SAMPLES_PATH)/../../ \ + OUTPUT=$(BPFTOOL_OUTPUT)/ bootstrap + +$(LIBBPF_OUTPUT) $(BPFTOOL_OUTPUT): + $(call msg,MKDIR,$@) + $(Q)mkdir -p $@ + +FORCE: + + +# Verify LLVM compiler tools are available and bpf target is supported by llc +.PHONY: verify_cmds verify_target_bpf $(CLANG) $(LLC) + +verify_cmds: $(CLANG) $(LLC) + @for TOOL in $^ ; do \ + if ! (which -- "$${TOOL}" > /dev/null 2>&1); then \ + echo "*** ERROR: Cannot find LLVM tool $${TOOL}" ;\ + exit 1; \ + else true; fi; \ + done + +verify_target_bpf: verify_cmds + @if ! (${LLC} -march=bpf -mattr=help > /dev/null 2>&1); then \ + echo "*** ERROR: LLVM (${LLC}) does not support 'bpf' target" ;\ + echo " NOTICE: LLVM version >= 3.7.1 required" ;\ + exit 2; \ + else true; fi + +$(HID_SAMPLES_PATH)/*.c: verify_target_bpf $(LIBBPF) +$(src)/*.c: verify_target_bpf $(LIBBPF) + +libbpf_hdrs: $(LIBBPF) + +.PHONY: libbpf_hdrs + +$(obj)/hid_mouse.o: $(obj)/hid_mouse.skel.h + +-include $(HID_SAMPLES_PATH)/Makefile.target + +VMLINUX_BTF_PATHS ?= $(abspath $(if $(O),$(O)/vmlinux)) \ + $(abspath $(if $(KBUILD_OUTPUT),$(KBUILD_OUTPUT)/vmlinux)) \ + $(abspath ./vmlinux) +VMLINUX_BTF ?= $(abspath $(firstword $(wildcard $(VMLINUX_BTF_PATHS)))) + +$(obj)/vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL) +ifeq ($(VMLINUX_H),) +ifeq ($(VMLINUX_BTF),) + $(error Cannot find a vmlinux for VMLINUX_BTF at any of "$(VMLINUX_BTF_PATHS)",\ + build the kernel or set VMLINUX_BTF or VMLINUX_H variable) +endif + $(Q)$(BPFTOOL) btf dump file $(VMLINUX_BTF) format c > $@ +else + $(Q)cp "$(VMLINUX_H)" $@ +endif + +clean-files += vmlinux.h + +# Get Clang's default includes on this system, as opposed to those seen by +# '-target bpf'. This fixes "missing" files on some architectures/distros, +# such as asm/byteorder.h, asm/socket.h, asm/sockios.h, sys/cdefs.h etc. +# +# Use '-idirafter': Don't interfere with include mechanics except where the +# build would have failed anyways. +define get_sys_includes +$(shell $(1) -v -E - </dev/null 2>&1 \ + | sed -n '/<...> search starts here:/,/End of search list./{ s| \(/.*\)|-idirafter \1|p }') \ +$(shell $(1) -dM -E - </dev/null | grep '#define __riscv_xlen ' | sed 's/#define /-D/' | sed 's/ /=/') +endef + +CLANG_SYS_INCLUDES = $(call get_sys_includes,$(CLANG)) + +EXTRA_BPF_HEADERS_SRC := $(addprefix $(src)/,$(EXTRA_BPF_HEADERS)) + +$(obj)/%.bpf.o: $(src)/%.bpf.c $(EXTRA_BPF_HEADERS_SRC) $(obj)/vmlinux.h + @echo " CLANG-BPF " $@ + $(Q)$(CLANG) -g -O2 -target bpf -D__TARGET_ARCH_$(SRCARCH) \ + -Wno-compare-distinct-pointer-types -I$(srctree)/include \ + -I$(srctree)/samples/bpf -I$(srctree)/tools/include \ + -I$(LIBBPF_INCLUDE) $(CLANG_SYS_INCLUDES) \ + -c $(filter %.bpf.c,$^) -o $@ + +LINKED_SKELS := hid_mouse.skel.h +clean-files += $(LINKED_SKELS) + +hid_mouse.skel.h-deps := hid_mouse.bpf.o hid_bpf_attach.bpf.o + +LINKED_BPF_SRCS := $(patsubst %.bpf.o,%.bpf.c,$(foreach skel,$(LINKED_SKELS),$($(skel)-deps))) + +BPF_SRCS_LINKED := $(notdir $(wildcard $(src)/*.bpf.c)) +BPF_OBJS_LINKED := $(patsubst %.bpf.c,$(obj)/%.bpf.o, $(BPF_SRCS_LINKED)) +BPF_SKELS_LINKED := $(addprefix $(obj)/,$(LINKED_SKELS)) + +$(BPF_SKELS_LINKED): $(BPF_OBJS_LINKED) $(BPFTOOL) + @echo " BPF GEN-OBJ " $(@:.skel.h=) + $(Q)$(BPFTOOL) gen object $(@:.skel.h=.lbpf.o) $(addprefix $(obj)/,$($(@F)-deps)) + @echo " BPF GEN-SKEL" $(@:.skel.h=) + $(Q)$(BPFTOOL) gen skeleton $(@:.skel.h=.lbpf.o) name $(notdir $(@:.skel.h=)) > $@ + +# asm/sysreg.h - inline assembly used by it is incompatible with llvm. +# But, there is no easy way to fix it, so just exclude it since it is +# useless for BPF samples. +# below we use long chain of commands, clang | opt | llvm-dis | llc, +# to generate final object file. 'clang' compiles the source into IR +# with native target, e.g., x64, arm64, etc. 'opt' does bpf CORE IR builtin +# processing (llvm12) and IR optimizations. 'llvm-dis' converts +# 'opt' output to IR, and finally 'llc' generates bpf byte code. +$(obj)/%.o: $(src)/%.c + @echo " CLANG-bpf " $@ + $(Q)$(CLANG) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(BPF_EXTRA_CFLAGS) \ + -I$(obj) -I$(srctree)/tools/testing/selftests/bpf/ \ + -I$(LIBBPF_INCLUDE) \ + -D__KERNEL__ -D__BPF_TRACING__ -Wno-unused-value -Wno-pointer-sign \ + -D__TARGET_ARCH_$(SRCARCH) -Wno-compare-distinct-pointer-types \ + -Wno-gnu-variable-sized-type-not-at-end \ + -Wno-address-of-packed-member -Wno-tautological-compare \ + -Wno-unknown-warning-option $(CLANG_ARCH_ARGS) \ + -fno-asynchronous-unwind-tables \ + -I$(srctree)/samples/hid/ \ + -O2 -emit-llvm -Xclang -disable-llvm-passes -c $< -o - | \ + $(OPT) -O2 -mtriple=bpf-pc-linux | $(LLVM_DIS) | \ + $(LLC) -march=bpf $(LLC_FLAGS) -filetype=obj -o $@ +ifeq ($(DWARF2BTF),y) + $(BTF_PAHOLE) -J $@ +endif diff --git a/samples/hid/Makefile.target b/samples/hid/Makefile.target new file mode 100644 index 000000000000..7621f55e2947 --- /dev/null +++ b/samples/hid/Makefile.target @@ -0,0 +1,75 @@ +# SPDX-License-Identifier: GPL-2.0 +# ========================================================================== +# Building binaries on the host system +# Binaries are not used during the compilation of the kernel, and intended +# to be build for target board, target board can be host of course. Added to +# build binaries to run not on host system. +# +# Sample syntax +# tprogs-y := xsk_example +# Will compile xsk_example.c and create an executable named xsk_example +# +# tprogs-y := xdpsock +# xdpsock-objs := xdpsock_1.o xdpsock_2.o +# Will compile xdpsock_1.c and xdpsock_2.c, and then link the executable +# xdpsock, based on xdpsock_1.o and xdpsock_2.o +# +# Derived from scripts/Makefile.host +# +__tprogs := $(sort $(tprogs-y)) + +# C code +# Executables compiled from a single .c file +tprog-csingle := $(foreach m,$(__tprogs), \ + $(if $($(m)-objs),,$(m))) + +# C executables linked based on several .o files +tprog-cmulti := $(foreach m,$(__tprogs),\ + $(if $($(m)-objs),$(m))) + +# Object (.o) files compiled from .c files +tprog-cobjs := $(sort $(foreach m,$(__tprogs),$($(m)-objs))) + +tprog-csingle := $(addprefix $(obj)/,$(tprog-csingle)) +tprog-cmulti := $(addprefix $(obj)/,$(tprog-cmulti)) +tprog-cobjs := $(addprefix $(obj)/,$(tprog-cobjs)) + +##### +# Handle options to gcc. Support building with separate output directory + +_tprogc_flags = $(TPROGS_CFLAGS) \ + $(TPROGCFLAGS_$(basetarget).o) + +# $(objtree)/$(obj) for including generated headers from checkin source files +ifeq ($(KBUILD_EXTMOD),) +ifdef building_out_of_srctree +_tprogc_flags += -I $(objtree)/$(obj) +endif +endif + +tprogc_flags = -Wp,-MD,$(depfile) $(_tprogc_flags) + +# Create executable from a single .c file +# tprog-csingle -> Executable +quiet_cmd_tprog-csingle = CC $@ + cmd_tprog-csingle = $(CC) $(tprogc_flags) $(TPROGS_LDFLAGS) -o $@ $< \ + $(TPROGS_LDLIBS) $(TPROGLDLIBS_$(@F)) +$(tprog-csingle): $(obj)/%: $(src)/%.c FORCE + $(call if_changed_dep,tprog-csingle) + +# Link an executable based on list of .o files, all plain c +# tprog-cmulti -> executable +quiet_cmd_tprog-cmulti = LD $@ + cmd_tprog-cmulti = $(CC) $(tprogc_flags) $(TPROGS_LDFLAGS) -o $@ \ + $(addprefix $(obj)/,$($(@F)-objs)) \ + $(TPROGS_LDLIBS) $(TPROGLDLIBS_$(@F)) +$(tprog-cmulti): $(tprog-cobjs) FORCE + $(call if_changed,tprog-cmulti) +$(call multi_depend, $(tprog-cmulti), , -objs) + +# Create .o file from a single .c file +# tprog-cobjs -> .o +quiet_cmd_tprog-cobjs = CC $@ + cmd_tprog-cobjs = $(CC) $(tprogc_flags) -c -o $@ $< +$(tprog-cobjs): $(obj)/%.o: $(src)/%.c FORCE + $(call if_changed_dep,tprog-cobjs) diff --git a/samples/hid/hid_bpf_attach.bpf.c b/samples/hid/hid_bpf_attach.bpf.c new file mode 100644 index 000000000000..d4dce4ea7c6e --- /dev/null +++ b/samples/hid/hid_bpf_attach.bpf.c @@ -0,0 +1,18 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (c) 2022 Benjamin Tissoires + */ + +#include "vmlinux.h" +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> +#include "hid_bpf_attach.h" +#include "hid_bpf_helpers.h" + +SEC("syscall") +int attach_prog(struct attach_prog_args *ctx) +{ + ctx->retval = hid_bpf_attach_prog(ctx->hid, + ctx->prog_fd, + 0); + return 0; +} diff --git a/samples/hid/hid_bpf_attach.h b/samples/hid/hid_bpf_attach.h new file mode 100644 index 000000000000..35bb28b49264 --- /dev/null +++ b/samples/hid/hid_bpf_attach.h @@ -0,0 +1,14 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* Copyright (c) 2022 Benjamin Tissoires + */ + +#ifndef __HID_BPF_ATTACH_H +#define __HID_BPF_ATTACH_H + +struct attach_prog_args { + int prog_fd; + unsigned int hid; + int retval; +}; + +#endif /* __HID_BPF_ATTACH_H */ diff --git a/samples/hid/hid_bpf_helpers.h b/samples/hid/hid_bpf_helpers.h new file mode 100644 index 000000000000..c555aeef5e37 --- /dev/null +++ b/samples/hid/hid_bpf_helpers.h @@ -0,0 +1,19 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* Copyright (c) 2022 Benjamin Tissoires + */ + +#ifndef __HID_BPF_HELPERS_H +#define __HID_BPF_HELPERS_H + +/* following are kfuncs exported by HID for HID-BPF */ +extern __u8 *hid_bpf_get_data(struct hid_bpf_ctx *ctx, + unsigned int offset, + const size_t __sz) __ksym; +extern int hid_bpf_attach_prog(unsigned int hid_id, int prog_fd, u32 flags) __ksym; +extern int hid_bpf_hw_request(struct hid_bpf_ctx *ctx, + __u8 *data, + size_t buf__sz, + enum hid_report_type type, + enum hid_class_request reqtype) __ksym; + +#endif /* __HID_BPF_HELPERS_H */ diff --git a/samples/hid/hid_mouse.bpf.c b/samples/hid/hid_mouse.bpf.c new file mode 100644 index 000000000000..7c8b453ccb16 --- /dev/null +++ b/samples/hid/hid_mouse.bpf.c @@ -0,0 +1,112 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include "vmlinux.h" +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> +#include "hid_bpf_helpers.h" + +SEC("fmod_ret/hid_bpf_device_event") +int BPF_PROG(hid_y_event, struct hid_bpf_ctx *hctx) +{ + s16 y; + __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 9 /* size */); + + if (!data) + return 0; /* EPERM check */ + + bpf_printk("event: size: %d", hctx->size); + bpf_printk("incoming event: %02x %02x %02x", + data[0], + data[1], + data[2]); + bpf_printk(" %02x %02x %02x", + data[3], + data[4], + data[5]); + bpf_printk(" %02x %02x %02x", + data[6], + data[7], + data[8]); + + y = data[3] | (data[4] << 8); + + y = -y; + + data[3] = y & 0xFF; + data[4] = (y >> 8) & 0xFF; + + bpf_printk("modified event: %02x %02x %02x", + data[0], + data[1], + data[2]); + bpf_printk(" %02x %02x %02x", + data[3], + data[4], + data[5]); + bpf_printk(" %02x %02x %02x", + data[6], + data[7], + data[8]); + + return 0; +} + +SEC("fmod_ret/hid_bpf_device_event") +int BPF_PROG(hid_x_event, struct hid_bpf_ctx *hctx) +{ + s16 x; + __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 9 /* size */); + + if (!data) + return 0; /* EPERM check */ + + x = data[1] | (data[2] << 8); + + x = -x; + + data[1] = x & 0xFF; + data[2] = (x >> 8) & 0xFF; + return 0; +} + +SEC("fmod_ret/hid_bpf_rdesc_fixup") +int BPF_PROG(hid_rdesc_fixup, struct hid_bpf_ctx *hctx) +{ + __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 4096 /* size */); + + if (!data) + return 0; /* EPERM check */ + + bpf_printk("rdesc: %02x %02x %02x", + data[0], + data[1], + data[2]); + bpf_printk(" %02x %02x %02x", + data[3], + data[4], + data[5]); + bpf_printk(" %02x %02x %02x ...", + data[6], + data[7], + data[8]); + + /* + * The original report descriptor contains: + * + * 0x05, 0x01, // Usage Page (Generic Desktop) 30 + * 0x16, 0x01, 0x80, // Logical Minimum (-32767) 32 + * 0x26, 0xff, 0x7f, // Logical Maximum (32767) 35 + * 0x09, 0x30, // Usage (X) 38 + * 0x09, 0x31, // Usage (Y) 40 + * + * So byte 39 contains Usage X and byte 41 Usage Y. + * + * We simply swap the axes here. + */ + data[39] = 0x31; + data[41] = 0x30; + + return 0; +} + +char _license[] SEC("license") = "GPL"; diff --git a/samples/hid/hid_mouse.c b/samples/hid/hid_mouse.c new file mode 100644 index 000000000000..018f1185f203 --- /dev/null +++ b/samples/hid/hid_mouse.c @@ -0,0 +1,155 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (c) 2022 Benjamin Tissoires + * + * This is a pure HID-BPF example, and should be considered as such: + * on the Etekcity Scroll 6E, the X and Y axes will be swapped and + * inverted. On any other device... Not sure what this will do. + * + * This C main file is generic though. To adapt the code and test, users + * must amend only the .bpf.c file, which this program will load any + * eBPF program it finds. + */ + +#include <assert.h> +#include <errno.h> +#include <fcntl.h> +#include <libgen.h> +#include <signal.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/resource.h> +#include <unistd.h> + +#include <linux/bpf.h> +#include <linux/errno.h> + +#include <bpf/bpf.h> +#include <bpf/libbpf.h> + +#include "hid_mouse.skel.h" +#include "hid_bpf_attach.h" + +static bool running = true; + +static void int_exit(int sig) +{ + running = false; + exit(0); +} + +static void usage(const char *prog) +{ + fprintf(stderr, + "%s: %s /sys/bus/hid/devices/0BUS:0VID:0PID:00ID\n\n", + __func__, prog); + fprintf(stderr, + "This program will upload and attach a HID-BPF program to the given device.\n" + "On the Etekcity Scroll 6E, the X and Y axis will be inverted, but on any other\n" + "device, chances are high that the device will not be working anymore\n\n" + "consider this as a demo and adapt the eBPF program to your needs\n" + "Hit Ctrl-C to unbind the program and reset the device\n"); +} + +static int get_hid_id(const char *path) +{ + const char *str_id, *dir; + char uevent[1024]; + int fd; + + memset(uevent, 0, sizeof(uevent)); + snprintf(uevent, sizeof(uevent) - 1, "%s/uevent", path); + + fd = open(uevent, O_RDONLY | O_NONBLOCK); + if (fd < 0) + return -ENOENT; + + close(fd); + + dir = basename((char *)path); + + str_id = dir + sizeof("0003:0001:0A37."); + return (int)strtol(str_id, NULL, 16); +} + +int main(int argc, char **argv) +{ + struct hid_mouse *skel; + struct bpf_program *prog; + int err; + const char *optstr = ""; + const char *sysfs_path; + int opt, hid_id, attach_fd; + struct attach_prog_args args = { + .retval = -1, + }; + DECLARE_LIBBPF_OPTS(bpf_test_run_opts, tattr, + .ctx_in = &args, + .ctx_size_in = sizeof(args), + ); + + while ((opt = getopt(argc, argv, optstr)) != -1) { + switch (opt) { + default: + usage(basename(argv[0])); + return 1; + } + } + + if (optind == argc) { + usage(basename(argv[0])); + return 1; + } + + sysfs_path = argv[optind]; + if (!sysfs_path) { + perror("sysfs"); + return 1; + } + + skel = hid_mouse__open_and_load(); + if (!skel) { + fprintf(stderr, "%s %s:%d", __func__, __FILE__, __LINE__); + return -1; + } + + hid_id = get_hid_id(sysfs_path); + + if (hid_id < 0) { + fprintf(stderr, "can not open HID device: %m\n"); + return 1; + } + args.hid = hid_id; + + attach_fd = bpf_program__fd(skel->progs.attach_prog); + if (attach_fd < 0) { + fprintf(stderr, "can't locate attach prog: %m\n"); + return 1; + } + + bpf_object__for_each_program(prog, *skel->skeleton->obj) { + /* ignore syscalls */ + if (bpf_program__get_type(prog) != BPF_PROG_TYPE_TRACING) + continue; + + args.retval = -1; + args.prog_fd = bpf_program__fd(prog); + err = bpf_prog_test_run_opts(attach_fd, &tattr); + if (err) { + fprintf(stderr, "can't attach prog to hid device %d: %m (err: %d)\n", + hid_id, err); + return 1; + } + } + + signal(SIGINT, int_exit); + signal(SIGTERM, int_exit); + + while (running) + sleep(1); + + hid_mouse__destroy(skel); + + return 0; +} |