convert ioctl time64 fallbacks to table-driven framework

[musl] / src / misc / ioctl.c

diff --git a/src/misc/ioctl.c b/src/misc/ioctl.c
index 6f31d4b..48613b3 100644 (file)
--- a/src/misc/ioctl.c
+++ b/src/misc/ioctl.c
@@ -3,8 +3,63 @@
 #include <errno.h>
 #include <time.h>
 #include <sys/time.h>
+#include <stddef.h>
+#include <string.h>
 #include "syscall.h"
 
+#define alignof(t) offsetof(struct { char c; t x; }, x)
+
+#define W 1
+#define R 2
+#define WR 3
+
+struct ioctl_compat_map {
+       int new_req, old_req, old_size;
+       char dir, force_align;
+       int offsets[4];
+};
+
+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 } },
+};
+
+static void convert_ioctl_struct(const struct ioctl_compat_map *map, char *old, char *new, int dir)
+{
+       int new_offset = 0;
+       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++) {
+               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];
+               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);
+               } 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);
+               }
+               new_offset += sizeof new_ts;
+               old_offset += sizeof old_ts;
+       }
+       if (dir==W) memcpy(old+old_offset, new+new_offset, old_size-old_offset);
+       else memcpy(new+new_offset, old+old_offset, old_size-old_offset);
+}
+
 int ioctl(int fd, int req, ...)
 {
        void *arg;
@@ -13,23 +68,17 @@ int ioctl(int fd, int req, ...)
        arg = va_arg(ap, void *);
        va_end(ap);
        int r = __syscall(SYS_ioctl, fd, req, arg);
-       if (r==-ENOTTY) switch (req) {
-       case SIOCGSTAMP:
-       case SIOCGSTAMPNS:
-               if (SIOCGSTAMP==SIOCGSTAMP_OLD) break;
-               if (req==SIOCGSTAMP) req=SIOCGSTAMP_OLD;
-               if (req==SIOCGSTAMPNS) req=SIOCGSTAMPNS_OLD;
-               long t32[2];
-               r = __syscall(SYS_ioctl, fd, req, t32);
-               if (r<0) break;
-               if (req==SIOCGSTAMP_OLD) {
-                       struct timeval *tv = arg;
-                       tv->tv_sec = t32[0];
-                       tv->tv_usec = t32[1];
-               } else {
-                       struct timespec *ts = arg;
-                       ts->tv_sec = t32[0];
-                       ts->tv_nsec = t32[1];
+       if (r==-ENOTTY) {
+               for (int i=0; i<sizeof compat_map/sizeof *compat_map; i++) {
+                       if (compat_map[i].new_req != req) continue;
+                       union {
+                               long long align;
+                               char buf[256];
+                       } u;
+                       convert_ioctl_struct(&compat_map[i], u.buf, arg, W);
+                       r = __syscall(SYS_ioctl, fd, compat_map[i].old_req, u.buf);
+                       if (r<0) break;
+                       convert_ioctl_struct(&compat_map[i], u.buf, arg, R);
                }
        }
        return __syscall_ret(r);