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improve ioctl time64 conversion fallback framework 

record offsets of individual slots that expand from 32- to 64-bit,
rather than timespec/timeval pairs. this flexibility will be needed
for some ioctls. reduce size of types in table. adjust representation
of offsets to include a count rather than needing -1 padding so that
the table is less ugly and doesn't need large diffs if we increase max
number of slots.
This commit is contained in:
Rich Felker 2019-12-19 10:47:10 -05:00
parent 221b1a1d0a
commit 64d0e86576
1 changed files with 18 additions and 17 deletions
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35
src/misc/ioctl.c
View File

@ -14,14 +14,18 @@
#define WR 3
struct ioctl_compat_map {
int new_req, old_req, old_size;
char dir, force_align;
int offsets[4];
int new_req, old_req;
unsigned char old_size, dir, force_align, noffs;
unsigned char offsets[8];
};
#define NINTH(a,b,c,d,e,f,g,h,i,...) i
#define COUNT(...) NINTH(__VA_ARGS__,8,7,6,5,4,3,2,1,0)
#define OFFS(...) COUNT(__VA_ARGS__), { __VA_ARGS__ }
static const struct ioctl_compat_map compat_map[] = {
{ SIOCGSTAMP, SIOCGSTAMP_OLD, 8, R, 0, { 0, -1, -1, -1 } },
{ SIOCGSTAMPNS, SIOCGSTAMPNS_OLD, 8, R, 0, { 0, -1, -1, -1 } },
{ SIOCGSTAMP, SIOCGSTAMP_OLD, 8, R, 0, OFFS(0, 4) },
{ SIOCGSTAMPNS, SIOCGSTAMPNS_OLD, 8, R, 0, OFFS(0, 4) },
};
static void convert_ioctl_struct(const struct ioctl_compat_map *map, char *old, char *new, int dir)
@ -30,28 +34,25 @@ static void convert_ioctl_struct(const struct ioctl_compat_map *map, char *old,
int old_offset = 0;
int old_size = map->old_size;
if (!(dir & map->dir)) return;
for (int i=0; i < sizeof map->offsets / sizeof *map->offsets; i++) {
for (int i=0; i < map->noffs; i++) {
int ts_offset = map->offsets[i];
if (ts_offset < 0) break;
int len = ts_offset-old_offset;
if (dir==W) memcpy(old+old_offset, new+new_offset, len);
else memcpy(new+new_offset, old+old_offset, len);
new_offset += len;
old_offset += len;
long long new_ts[2];
long old_ts[2];
long long new_ts;
long old_ts;
int align = map->force_align ? sizeof(time_t) : alignof(time_t);
new_offset += (align-1) & -new_offset;
if (dir==W) {
memcpy(new_ts, new+new_offset, sizeof new_ts);
old_ts[0] = new_ts[0];
old_ts[1] = new_ts[1];
memcpy(old+old_offset, old_ts, sizeof old_ts);
memcpy(&new_ts, new+new_offset, sizeof new_ts);
old_ts = new_ts;
memcpy(old+old_offset, &old_ts, sizeof old_ts);
} else {
memcpy(old_ts, old+old_offset, sizeof old_ts);
new_ts[0] = old_ts[0];
new_ts[1] = old_ts[1];
memcpy(new+new_offset, new_ts, sizeof new_ts);
memcpy(&old_ts, old+old_offset, sizeof old_ts);
new_ts = old_ts;
memcpy(new+new_offset, &new_ts, sizeof new_ts);
}
new_offset += sizeof new_ts;
old_offset += sizeof old_ts;