stage1: implement wasi seek shim

This commit is contained in:
Jacob Young 2023-11-09 19:54:08 -05:00
parent 10f4486c0b
commit a67d378543

View file

@ -178,6 +178,12 @@ struct wasi_ciovec {
uint32_t len;
};
enum wasi_whence {
wasi_whence_set = 0,
wasi_whence_cur = 1,
wasi_whence_end = 2,
};
extern uint8_t **const wasm_memory;
extern void wasm__start(void);
@ -946,6 +952,43 @@ uint32_t wasi_snapshot_preview1_fd_pread(uint32_t fd, uint32_t iovs, uint32_t io
return wasi_errno_success;
}
uint32_t wasi_snapshot_preview1_fd_seek(uint32_t fd, uint64_t in_offset, uint32_t whence, uint32_t res_filesize) {
uint8_t *const m = *wasm_memory;
int64_t offset = (int64_t)in_offset;
uint64_t *res_filesize_ptr = (uint64_t *)&m[res_filesize];
#if LOG_TRACE
fprintf(stderr, "wasi_snapshot_preview1_fd_seek(%u, 0x%lld, %u)\n", fd, (long long)offset, whence);
#endif
if (fd >= fd_len || fds[fd].de >= de_len) return wasi_errno_badf;
switch (des[fds[fd].de].filetype) {
case wasi_filetype_character_device: break;
case wasi_filetype_regular_file: break;
case wasi_filetype_directory: return wasi_errno_inval;
default: panic("unimplemented");
}
int seek_whence;
switch (whence) {
case wasi_whence_set:
seek_whence = SEEK_SET;
break;
case wasi_whence_cur:
seek_whence = SEEK_CUR;
break;
case wasi_whence_end:
seek_whence = SEEK_END;
break;
default:
return wasi_errno_inval;
}
if (fseek(fds[fd].stream, offset, seek_whence) < 0) return wasi_errno_io;
long res_offset = ftell(fds[fd].stream);
if (res_offset < 0) return wasi_errno_io;
*res_filesize_ptr = (uint64_t)res_offset;
return wasi_errno_success;
}
uint32_t wasi_snapshot_preview1_poll_oneoff(uint32_t in, uint32_t out, uint32_t nsubscriptions, uint32_t res_nevents) {
(void)in;
(void)out;
@ -959,7 +1002,6 @@ uint32_t wasi_snapshot_preview1_poll_oneoff(uint32_t in, uint32_t out, uint32_t
return wasi_errno_success;
}
void wasi_snapshot_preview1_debug(uint32_t string, uint64_t x) {
uint8_t *const m = *wasm_memory;
const char *string_ptr = (const char *)&m[string];