xref: /third_party/musl/src/misc/ioctl.c (revision 570af302)
1#include <sys/ioctl.h>
2#include <stdarg.h>
3#include <errno.h>
4#include <time.h>
5#include <sys/time.h>
6#include <stddef.h>
7#include <stdint.h>
8#include <string.h>
9#include <endian.h>
10#include "syscall.h"
11
12#define alignof(t) offsetof(struct { char c; t x; }, x)
13
14#define W 1
15#define R 2
16#define WR 3
17
18struct ioctl_compat_map {
19	int new_req, old_req;
20	unsigned char old_size, dir, force_align, noffs;
21	unsigned char offsets[8];
22};
23
24#define NINTH(a,b,c,d,e,f,g,h,i,...) i
25#define COUNT(...) NINTH(__VA_ARGS__,8,7,6,5,4,3,2,1,0)
26#define OFFS(...) COUNT(__VA_ARGS__), { __VA_ARGS__ }
27
28/* yields a type for a struct with original size n, with a misaligned
29 * timeval/timespec expanded from 32- to 64-bit. for use with ioctl
30 * number producing macros; only size of result is meaningful. */
31#define new_misaligned(n) struct { int i; time_t t; char c[(n)-4]; }
32
33struct v4l2_event {
34	uint32_t a;
35	uint64_t b[8];
36	uint32_t c[2], ts[2], d[9];
37};
38
39static const struct ioctl_compat_map compat_map[] = {
40	{ SIOCGSTAMP, SIOCGSTAMP_OLD, 8, R, 0, OFFS(0, 4) },
41	{ SIOCGSTAMPNS, SIOCGSTAMPNS_OLD, 8, R, 0, OFFS(0, 4) },
42
43	/* SNDRV_TIMER_IOCTL_STATUS */
44	{ _IOR('T', 0x14, char[96]), _IOR('T', 0x14, 88), 88, R, 0, OFFS(0,4) },
45
46	/* SNDRV_PCM_IOCTL_STATUS[_EXT] */
47	{ _IOR('A', 0x20, char[128]), _IOR('A', 0x20, char[108]), 108, R, 1, OFFS(4,8,12,16,52,56,60,64) },
48	{ _IOWR('A', 0x24, char[128]), _IOWR('A', 0x24, char[108]), 108, WR, 1, OFFS(4,8,12,16,52,56,60,64) },
49
50	/* SNDRV_RAWMIDI_IOCTL_STATUS */
51	{ _IOWR('W', 0x20, char[48]), _IOWR('W', 0x20, char[36]), 36, WR, 1, OFFS(4,8) },
52
53	/* SNDRV_PCM_IOCTL_SYNC_PTR - with 3 subtables */
54	{ _IOWR('A', 0x23, char[136]), _IOWR('A', 0x23, char[132]), 0, WR, 1, 0 },
55	{ 0, 0, 4, WR, 1, 0 }, /* snd_pcm_sync_ptr (flags only) */
56	{ 0, 0, 32, WR, 1, OFFS(8,12,16,24,28) }, /* snd_pcm_mmap_status */
57	{ 0, 0, 4, WR, 1, 0 }, /* snd_pcm_mmap_control (each member) */
58
59	/* VIDIOC_QUERYBUF, VIDIOC_QBUF, VIDIOC_DQBUF, VIDIOC_PREPARE_BUF */
60	{ _IOWR('V',  9, new_misaligned(68)), _IOWR('V',  9, char[68]), 68, WR, 1, OFFS(20, 24) },
61	{ _IOWR('V', 15, new_misaligned(68)), _IOWR('V', 15, char[68]), 68, WR, 1, OFFS(20, 24) },
62	{ _IOWR('V', 17, new_misaligned(68)), _IOWR('V', 17, char[68]), 68, WR, 1, OFFS(20, 24) },
63	{ _IOWR('V', 93, new_misaligned(68)), _IOWR('V', 93, char[68]), 68, WR, 1, OFFS(20, 24) },
64
65	/* VIDIOC_DQEVENT */
66	{ _IOR('V', 89, new_misaligned(120)), _IOR('V', 89, struct v4l2_event), sizeof(struct v4l2_event),
67	  R, 0, OFFS(offsetof(struct v4l2_event, ts[0]), offsetof(struct v4l2_event, ts[1])) },
68
69	/* VIDIOC_OMAP3ISP_STAT_REQ */
70	{ _IOWR('V', 192+6, char[32]), _IOWR('V', 192+6, char[24]), 22, WR, 0, OFFS(0,4) },
71
72	/* PPPIOCGIDLE */
73	{ _IOR('t', 63, char[16]), _IOR('t', 63, char[8]), 8, R, 0, OFFS(0,4) },
74
75	/* PPGETTIME, PPSETTIME */
76	{ _IOR('p', 0x95, char[16]), _IOR('p', 0x95, char[8]), 8, R, 0, OFFS(0,4) },
77	{ _IOW('p', 0x96, char[16]), _IOW('p', 0x96, char[8]), 8, W, 0, OFFS(0,4) },
78
79	/* LPSETTIMEOUT */
80	{ _IOW(0x6, 0xf, char[16]), 0x060f, 8, W, 0, OFFS(0,4) },
81};
82
83static void convert_ioctl_struct(const struct ioctl_compat_map *map, char *old, char *new, int dir)
84{
85	int new_offset = 0;
86	int old_offset = 0;
87	int old_size = map->old_size;
88	if (!(dir & map->dir)) return;
89	if (!map->old_size) {
90		/* offsets hard-coded for SNDRV_PCM_IOCTL_SYNC_PTR;
91		 * if another exception appears this needs changing. */
92		convert_ioctl_struct(map+1, old, new, dir);
93		convert_ioctl_struct(map+2, old+4, new+8, dir);
94		/* snd_pcm_mmap_control, special-cased due to kernel
95		 * type definition having been botched. */
96		int adj = BYTE_ORDER==BIG_ENDIAN ? 4 : 0;
97		convert_ioctl_struct(map+3, old+68, new+72+adj, dir);
98		convert_ioctl_struct(map+3, old+72, new+76+3*adj, dir);
99		return;
100	}
101	for (int i=0; i < map->noffs; i++) {
102		int ts_offset = map->offsets[i];
103		int len = ts_offset-old_offset;
104		if (dir==W) memcpy(old+old_offset, new+new_offset, len);
105		else memcpy(new+new_offset, old+old_offset, len);
106		new_offset += len;
107		old_offset += len;
108		long long new_ts;
109		long old_ts;
110		int align = map->force_align ? sizeof(time_t) : alignof(time_t);
111		new_offset += (align-1) & -new_offset;
112		if (dir==W) {
113			memcpy(&new_ts, new+new_offset, sizeof new_ts);
114			old_ts = new_ts;
115			memcpy(old+old_offset, &old_ts, sizeof old_ts);
116		} else {
117			memcpy(&old_ts, old+old_offset, sizeof old_ts);
118			new_ts = old_ts;
119			memcpy(new+new_offset, &new_ts, sizeof new_ts);
120		}
121		new_offset += sizeof new_ts;
122		old_offset += sizeof old_ts;
123	}
124	if (dir==W) memcpy(old+old_offset, new+new_offset, old_size-old_offset);
125	else memcpy(new+new_offset, old+old_offset, old_size-old_offset);
126}
127
128int ioctl(int fd, int req, ...)
129{
130	void *arg;
131	va_list ap;
132	va_start(ap, req);
133	arg = va_arg(ap, void *);
134	va_end(ap);
135	int r = __syscall(SYS_ioctl, fd, req, arg);
136	if (SIOCGSTAMP != SIOCGSTAMP_OLD && req && r==-ENOTTY) {
137		for (int i=0; i<sizeof compat_map/sizeof *compat_map; i++) {
138			if (compat_map[i].new_req != req) continue;
139			union {
140				long long align;
141				char buf[256];
142			} u;
143			convert_ioctl_struct(&compat_map[i], u.buf, arg, W);
144			r = __syscall(SYS_ioctl, fd, compat_map[i].old_req, u.buf);
145			if (r<0) break;
146			convert_ioctl_struct(&compat_map[i], u.buf, arg, R);
147			break;
148		}
149	}
150	return __syscall_ret(r);
151}
152