improve ioctl time64 conversion fallback framework

[musl] / src / misc / ioctl.c

diff --git a/src/misc/ioctl.c b/src/misc/ioctl.c
index 5a41f0e..245876e 100644 (file)
--- a/src/misc/ioctl.c
+++ b/src/misc/ioctl.c
@@ -1,7 +1,66 @@
 #include <sys/ioctl.h>
 #include <stdarg.h>
+#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;
+       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, 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)
+{
+       int new_offset = 0;
+       int old_offset = 0;
+       int old_size = map->old_size;
+       if (!(dir & map->dir)) return;
+       for (int i=0; i < map->noffs; i++) {
+               int ts_offset = map->offsets[i];
+               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;
+               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 = new_ts;
+                       memcpy(old+old_offset, &old_ts, sizeof old_ts);
+               } else {
+                       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;
+       }
+       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;
@@ -9,5 +68,19 @@ int ioctl(int fd, int req, ...)
        va_start(ap, req);
        arg = va_arg(ap, void *);
        va_end(ap);
-       return syscall(SYS_ioctl, fd, req, arg);
+       int r = __syscall(SYS_ioctl, fd, req, arg);
+       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);
 }