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1// SPDX-License-Identifier: GPL-2.0-only
2/* Copyright (c) 2022 Benjamin Tissoires
3 *
4 * This program will morph the Microsoft Surface Dial into a mouse,
5 * and depending on the chosen resolution enable or not the haptic feedback:
6 * - a resolution (-r) of 3600 will report 3600 "ticks" in one full rotation
7 * without haptic feedback
8 * - any other resolution will report N "ticks" in a full rotation with haptic
9 * feedback
10 *
11 * A good default for low resolution haptic scrolling is 72 (1 "tick" every 5
12 * degrees), and set to 3600 for smooth scrolling.
13 */
14
15#include <assert.h>
16#include <errno.h>
17#include <fcntl.h>
18#include <libgen.h>
19#include <signal.h>
20#include <stdbool.h>
21#include <stdio.h>
22#include <stdlib.h>
23#include <string.h>
24#include <sys/resource.h>
25#include <unistd.h>
26
27#include <linux/bpf.h>
28#include <linux/errno.h>
29
30#include <bpf/bpf.h>
31#include <bpf/libbpf.h>
32
33#include "hid_surface_dial.skel.h"
34#include "hid_bpf_attach.h"
35
36static bool running = true;
37
38struct haptic_syscall_args {
39 unsigned int hid;
40 int retval;
41};
42
43static void int_exit(int sig)
44{
45 running = false;
46 exit(0);
47}
48
49static void usage(const char *prog)
50{
51 fprintf(stderr,
52 "%s: %s [OPTIONS] /sys/bus/hid/devices/0BUS:0VID:0PID:00ID\n\n"
53 " OPTIONS:\n"
54 " -r N\t set the given resolution to the device (number of ticks per 360°)\n\n",
55 __func__, prog);
56 fprintf(stderr,
57 "This program will morph the Microsoft Surface Dial into a mouse,\n"
58 "and depending on the chosen resolution enable or not the haptic feedback:\n"
59 "- a resolution (-r) of 3600 will report 3600 'ticks' in one full rotation\n"
60 " without haptic feedback\n"
61 "- any other resolution will report N 'ticks' in a full rotation with haptic\n"
62 " feedback\n"
63 "\n"
64 "A good default for low resolution haptic scrolling is 72 (1 'tick' every 5\n"
65 "degrees), and set to 3600 for smooth scrolling.\n");
66}
67
68static int get_hid_id(const char *path)
69{
70 const char *str_id, *dir;
71 char uevent[1024];
72 int fd;
73
74 memset(uevent, 0, sizeof(uevent));
75 snprintf(uevent, sizeof(uevent) - 1, "%s/uevent", path);
76
77 fd = open(uevent, O_RDONLY | O_NONBLOCK);
78 if (fd < 0)
79 return -ENOENT;
80
81 close(fd);
82
83 dir = basename((char *)path);
84
85 str_id = dir + sizeof("0003:0001:0A37.");
86 return (int)strtol(str_id, NULL, 16);
87}
88
89static int attach_prog(struct hid_surface_dial *skel, struct bpf_program *prog, int hid_id)
90{
91 struct attach_prog_args args = {
92 .hid = hid_id,
93 .retval = -1,
94 };
95 int attach_fd, err;
96 DECLARE_LIBBPF_OPTS(bpf_test_run_opts, tattr,
97 .ctx_in = &args,
98 .ctx_size_in = sizeof(args),
99 );
100
101 attach_fd = bpf_program__fd(skel->progs.attach_prog);
102 if (attach_fd < 0) {
103 fprintf(stderr, "can't locate attach prog: %m\n");
104 return 1;
105 }
106
107 args.prog_fd = bpf_program__fd(prog);
108 err = bpf_prog_test_run_opts(attach_fd, &tattr);
109 if (err) {
110 fprintf(stderr, "can't attach prog to hid device %d: %m (err: %d)\n",
111 hid_id, err);
112 return 1;
113 }
114 return 0;
115}
116
117static int set_haptic(struct hid_surface_dial *skel, int hid_id)
118{
119 struct haptic_syscall_args args = {
120 .hid = hid_id,
121 .retval = -1,
122 };
123 int haptic_fd, err;
124 DECLARE_LIBBPF_OPTS(bpf_test_run_opts, tattr,
125 .ctx_in = &args,
126 .ctx_size_in = sizeof(args),
127 );
128
129 haptic_fd = bpf_program__fd(skel->progs.set_haptic);
130 if (haptic_fd < 0) {
131 fprintf(stderr, "can't locate haptic prog: %m\n");
132 return 1;
133 }
134
135 err = bpf_prog_test_run_opts(haptic_fd, &tattr);
136 if (err) {
137 fprintf(stderr, "can't set haptic configuration to hid device %d: %m (err: %d)\n",
138 hid_id, err);
139 return 1;
140 }
141 return 0;
142}
143
144int main(int argc, char **argv)
145{
146 struct hid_surface_dial *skel;
147 struct bpf_program *prog;
148 const char *optstr = "r:";
149 const char *sysfs_path;
150 int opt, hid_id, resolution = 72;
151
152 while ((opt = getopt(argc, argv, optstr)) != -1) {
153 switch (opt) {
154 case 'r':
155 {
156 char *endp = NULL;
157 long l = -1;
158
159 if (optarg) {
160 l = strtol(optarg, &endp, 10);
161 if (endp && *endp)
162 l = -1;
163 }
164
165 if (l < 0) {
166 fprintf(stderr,
167 "invalid r option %s - expecting a number\n",
168 optarg ? optarg : "");
169 exit(EXIT_FAILURE);
170 };
171
172 resolution = (int) l;
173 break;
174 }
175 default:
176 usage(basename(argv[0]));
177 return 1;
178 }
179 }
180
181 if (optind == argc) {
182 usage(basename(argv[0]));
183 return 1;
184 }
185
186 sysfs_path = argv[optind];
187 if (!sysfs_path) {
188 perror("sysfs");
189 return 1;
190 }
191
192 skel = hid_surface_dial__open_and_load();
193 if (!skel) {
194 fprintf(stderr, "%s %s:%d", __func__, __FILE__, __LINE__);
195 return -1;
196 }
197
198 hid_id = get_hid_id(sysfs_path);
199 if (hid_id < 0) {
200 fprintf(stderr, "can not open HID device: %m\n");
201 return 1;
202 }
203
204 skel->data->resolution = resolution;
205 skel->data->physical = (int)(resolution / 72);
206
207 bpf_object__for_each_program(prog, *skel->skeleton->obj) {
208 /* ignore syscalls */
209 if (bpf_program__get_type(prog) != BPF_PROG_TYPE_TRACING)
210 continue;
211
212 attach_prog(skel, prog, hid_id);
213 }
214
215 signal(SIGINT, int_exit);
216 signal(SIGTERM, int_exit);
217
218 set_haptic(skel, hid_id);
219
220 while (running)
221 sleep(1);
222
223 hid_surface_dial__destroy(skel);
224
225 return 0;
226}
1// SPDX-License-Identifier: GPL-2.0-only
2/* Copyright (c) 2022 Benjamin Tissoires
3 *
4 * This program will morph the Microsoft Surface Dial into a mouse,
5 * and depending on the chosen resolution enable or not the haptic feedback:
6 * - a resolution (-r) of 3600 will report 3600 "ticks" in one full rotation
7 * without haptic feedback
8 * - any other resolution will report N "ticks" in a full rotation with haptic
9 * feedback
10 *
11 * A good default for low resolution haptic scrolling is 72 (1 "tick" every 5
12 * degrees), and set to 3600 for smooth scrolling.
13 */
14
15#include <assert.h>
16#include <errno.h>
17#include <fcntl.h>
18#include <libgen.h>
19#include <signal.h>
20#include <stdbool.h>
21#include <stdio.h>
22#include <stdlib.h>
23#include <string.h>
24#include <sys/resource.h>
25#include <unistd.h>
26
27#include <linux/bpf.h>
28#include <linux/errno.h>
29
30#include <bpf/bpf.h>
31#include <bpf/libbpf.h>
32
33#include "hid_surface_dial.skel.h"
34#include "hid_bpf_attach.h"
35
36static bool running = true;
37
38struct haptic_syscall_args {
39 unsigned int hid;
40 int retval;
41};
42
43static void int_exit(int sig)
44{
45 running = false;
46 exit(0);
47}
48
49static void usage(const char *prog)
50{
51 fprintf(stderr,
52 "%s: %s [OPTIONS] /sys/bus/hid/devices/0BUS:0VID:0PID:00ID\n\n"
53 " OPTIONS:\n"
54 " -r N\t set the given resolution to the device (number of ticks per 360°)\n\n",
55 __func__, prog);
56 fprintf(stderr,
57 "This program will morph the Microsoft Surface Dial into a mouse,\n"
58 "and depending on the chosen resolution enable or not the haptic feedback:\n"
59 "- a resolution (-r) of 3600 will report 3600 'ticks' in one full rotation\n"
60 " without haptic feedback\n"
61 "- any other resolution will report N 'ticks' in a full rotation with haptic\n"
62 " feedback\n"
63 "\n"
64 "A good default for low resolution haptic scrolling is 72 (1 'tick' every 5\n"
65 "degrees), and set to 3600 for smooth scrolling.\n");
66}
67
68static int get_hid_id(const char *path)
69{
70 const char *str_id, *dir;
71 char uevent[1024];
72 int fd;
73
74 memset(uevent, 0, sizeof(uevent));
75 snprintf(uevent, sizeof(uevent) - 1, "%s/uevent", path);
76
77 fd = open(uevent, O_RDONLY | O_NONBLOCK);
78 if (fd < 0)
79 return -ENOENT;
80
81 close(fd);
82
83 dir = basename((char *)path);
84
85 str_id = dir + sizeof("0003:0001:0A37.");
86 return (int)strtol(str_id, NULL, 16);
87}
88
89static int attach_prog(struct hid_surface_dial *skel, struct bpf_program *prog, int hid_id)
90{
91 struct attach_prog_args args = {
92 .hid = hid_id,
93 .retval = -1,
94 };
95 int attach_fd, err;
96 DECLARE_LIBBPF_OPTS(bpf_test_run_opts, tattr,
97 .ctx_in = &args,
98 .ctx_size_in = sizeof(args),
99 );
100
101 attach_fd = bpf_program__fd(skel->progs.attach_prog);
102 if (attach_fd < 0) {
103 fprintf(stderr, "can't locate attach prog: %m\n");
104 return 1;
105 }
106
107 args.prog_fd = bpf_program__fd(prog);
108 err = bpf_prog_test_run_opts(attach_fd, &tattr);
109 if (err) {
110 fprintf(stderr, "can't attach prog to hid device %d: %m (err: %d)\n",
111 hid_id, err);
112 return 1;
113 }
114 return 0;
115}
116
117static int set_haptic(struct hid_surface_dial *skel, int hid_id)
118{
119 struct haptic_syscall_args args = {
120 .hid = hid_id,
121 .retval = -1,
122 };
123 int haptic_fd, err;
124 DECLARE_LIBBPF_OPTS(bpf_test_run_opts, tattr,
125 .ctx_in = &args,
126 .ctx_size_in = sizeof(args),
127 );
128
129 haptic_fd = bpf_program__fd(skel->progs.set_haptic);
130 if (haptic_fd < 0) {
131 fprintf(stderr, "can't locate haptic prog: %m\n");
132 return 1;
133 }
134
135 err = bpf_prog_test_run_opts(haptic_fd, &tattr);
136 if (err) {
137 fprintf(stderr, "can't set haptic configuration to hid device %d: %m (err: %d)\n",
138 hid_id, err);
139 return 1;
140 }
141 return 0;
142}
143
144int main(int argc, char **argv)
145{
146 struct hid_surface_dial *skel;
147 struct bpf_program *prog;
148 const char *optstr = "r:";
149 const char *sysfs_path;
150 int opt, hid_id, resolution = 72;
151
152 while ((opt = getopt(argc, argv, optstr)) != -1) {
153 switch (opt) {
154 case 'r':
155 {
156 char *endp = NULL;
157 long l = -1;
158
159 if (optarg) {
160 l = strtol(optarg, &endp, 10);
161 if (endp && *endp)
162 l = -1;
163 }
164
165 if (l < 0) {
166 fprintf(stderr,
167 "invalid r option %s - expecting a number\n",
168 optarg ? optarg : "");
169 exit(EXIT_FAILURE);
170 };
171
172 resolution = (int) l;
173 break;
174 }
175 default:
176 usage(basename(argv[0]));
177 return 1;
178 }
179 }
180
181 if (optind == argc) {
182 usage(basename(argv[0]));
183 return 1;
184 }
185
186 sysfs_path = argv[optind];
187 if (!sysfs_path) {
188 perror("sysfs");
189 return 1;
190 }
191
192 skel = hid_surface_dial__open_and_load();
193 if (!skel) {
194 fprintf(stderr, "%s %s:%d", __func__, __FILE__, __LINE__);
195 return -1;
196 }
197
198 hid_id = get_hid_id(sysfs_path);
199 if (hid_id < 0) {
200 fprintf(stderr, "can not open HID device: %m\n");
201 return 1;
202 }
203
204 skel->data->resolution = resolution;
205 skel->data->physical = (int)(resolution / 72);
206
207 bpf_object__for_each_program(prog, *skel->skeleton->obj) {
208 /* ignore syscalls */
209 if (bpf_program__get_type(prog) != BPF_PROG_TYPE_TRACING)
210 continue;
211
212 attach_prog(skel, prog, hid_id);
213 }
214
215 signal(SIGINT, int_exit);
216 signal(SIGTERM, int_exit);
217
218 set_haptic(skel, hid_id);
219
220 while (running)
221 sleep(1);
222
223 hid_surface_dial__destroy(skel);
224
225 return 0;
226}