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Copy only received bytes from socket recv buffer into the app buffer #1497

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Merged
merged 3 commits into from
Sep 20, 2022
Merged

Copy only received bytes from socket recv buffer into the app buffer #1497

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a8b45fb
Copy min amount from recv buffer
cimacmillan Sep 15, 2022
db6701e
Add size_to_copy argument to copy_buffer_to_iovec_app
cimacmillan Sep 20, 2022
70d4c3b
Remove unescessary size to copy check
cimacmillan Sep 20, 2022
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39 changes: 33 additions & 6 deletions core/iwasm/libraries/libc-wasi/libc_wasi_wrapper.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1841,6 +1841,11 @@ allocate_iovec_app_buffer(wasm_module_inst_t module_inst,
for (total_size = 0, i = 0; i < data_len; i++, data++) {
total_size += data->buf_len;
}

if (total_size == 0) {
return __WASI_EINVAL;
}

if (total_size >= UINT32_MAX
|| !(buf_begin = wasm_runtime_malloc((uint32)total_size))) {
return __WASI_ENOMEM;
Expand All @@ -1852,12 +1857,24 @@ allocate_iovec_app_buffer(wasm_module_inst_t module_inst,
return __WASI_ESUCCESS;
}

static inline size_t
min(size_t a, size_t b)
{
return a > b ? b : a;
}

static wasi_errno_t
copy_buffer_to_iovec_app(wasm_module_inst_t module_inst, uint8 *buf_begin,
uint32 buf_size, iovec_app_t *data, uint32 data_len)
uint32 buf_size, iovec_app_t *data, uint32 data_len,
uint32 size_to_copy)
{
uint8 *buf = buf_begin;
uint32 i;
uint32 size_to_copy_into_iovec;

if (buf_size < size_to_copy) {
return __WASI_EINVAL;
}

for (i = 0; i < data_len; data++, i++) {
char *native_addr;
Expand All @@ -1868,13 +1885,23 @@ copy_buffer_to_iovec_app(wasm_module_inst_t module_inst, uint8 *buf_begin,

if (buf >= buf_begin + buf_size
|| buf + data->buf_len < buf /* integer overflow */
|| buf + data->buf_len > buf_begin + buf_size) {
|| buf + data->buf_len > buf_begin + buf_size
|| size_to_copy == 0) {
break;
}

/**
* If our app buffer size is smaller than the amount to be copied,
* only copy the amount in the app buffer. Otherwise, we fill the iovec
* buffer and reduce size to copy on the next iteration
*/
size_to_copy_into_iovec = min(data->buf_len, size_to_copy);

native_addr = (void *)addr_app_to_native(data->buf_offset);
bh_memcpy_s(native_addr, data->buf_len, buf, data->buf_len);
buf += data->buf_len;
bh_memcpy_s(native_addr, size_to_copy_into_iovec, buf,
size_to_copy_into_iovec);
buf += size_to_copy_into_iovec;
size_to_copy -= size_to_copy_into_iovec;
}

return __WASI_ESUCCESS;
Expand Down Expand Up @@ -1921,8 +1948,8 @@ wasi_sock_recv_from(wasm_exec_env_t exec_env, wasi_fd_t sock,
}
*ro_data_len = (uint32)recv_bytes;

err = copy_buffer_to_iovec_app(module_inst, buf_begin, (uint32)recv_bytes,
ri_data, ri_data_len);
err = copy_buffer_to_iovec_app(module_inst, buf_begin, (uint32)total_size,
ri_data, ri_data_len, (uint32)recv_bytes);

fail:
if (buf_begin) {
Expand Down
2 changes: 2 additions & 0 deletions samples/socket-api/CMakeLists.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -91,6 +91,8 @@ ExternalProject_Add(wasm-app
tcp_server.wasm ${CMAKE_BINARY_DIR}
send_recv.wasm ${CMAKE_BINARY_DIR}
socket_opts.wasm ${CMAKE_BINARY_DIR}
udp_client.wasm ${CMAKE_BINARY_DIR}
udp_server.wasm ${CMAKE_BINARY_DIR}
)

add_executable(tcp_server ${CMAKE_CURRENT_SOURCE_DIR}/wasm-src/tcp_server.c)
Expand Down