wasi使用笔记

1
2

$ wasirun hello.wasm    
Hello wasi    

1
2
3
4
5
6
7

git clone https://github.com/juj/emsdk.git    
cd emsdk    
emsdk update    
emsdk install latest    
emsdk activate latest    
//如果没有出现emcc命令:    
source ./emsdk_env.sh    

1
2
3
4
5
6
7
8

# Extract the contents to a dir    
mkdir wasmer-c-api    
tar -C wasmer-c-api -zxvf wasmer-c-api*.tar.gz    
    
export WASMER_C_API=`pwd`/wasmer-c-api    
    
# Update LD_LIBRARY_PATH to link against the libwasmer.so in the examples    
export LD_LIBRARY_PATH=`pwd`/wasmer-c-api/lib/:$LD_LIBRARY_PATH    

1
2

静态链接：gcc test.c -I${WASMER_C_API}/include -L${WASMER_C_API}/lib -lwasmer -o test    
动态链接：gcc -static main.c -I${WASMER_C_API}/include -L${WASMER_C_API}/lib -lwasmer -lpthread -lm -ldl -o main    

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70

// wasm部分    
#include<stdio.h>    
    
int main()    
{    
char s[20] = {0};    
scanf("%s", s);    
puts(s);    
return 0;    
}    
// c部分    
#include <stdio.h>    
#include "wasmer.h"    
#include <assert.h>    
#include <stdint.h>    
    
// Function to print the most recent error string from Wasmer if we have them    
void print_wasmer_error()    
{    
int error_len = wasmer_last_error_length();    
char *error_str = malloc(error_len);    
wasmer_last_error_message(error_str, error_len);    
printf("Error: `%s`\n", error_str);    
}    
    
int main()    
{    
FILE *file = fopen("hello.wasm", "r");    
assert(file != NULL);    
fseek(file, 0, SEEK_END);    
long len = ftell(file);    
uint8_t *bytes = (uint8_t*)malloc(len);    
fseek(file, 0, SEEK_SET);    
fread(bytes, 1, len, file);    
fclose(file);    
    
wasmer_module_t *module = NULL;    
wasmer_result_t compile_result = wasmer_compile(&module, bytes, len);    
if (compile_result != WASMER_OK)    
{    
    print_wasmer_error();    
    return -1;    
}    
wasmer_import_object_t *wasi_import_obj = wasmer_wasi_generate_default_import_object();    
    
// find out what version of WASI the module is    
Version wasi_version = wasmer_wasi_get_version(module);    
// char* progname = "ProgramName";    
// wasmer_byte_array args[] = { { .bytes = progname; .bytes_len = sizeof(progname); } };    
wasmer_import_object_t * import_object = wasmer_wasi_generate_import_object_for_version(wasi_version, 0, 1, NULL, 0, NULL, 0, NULL, 0);    
    
// Instantiate a WebAssembly Instance from Wasm bytes and imports    
wasmer_instance_t *instance = NULL;    
// clock_gettime(CLOCK_REALTIME, &start);    
wasmer_result_t instantiate_result = wasmer_module_import_instantiate(&instance, module, import_object);    
    
if(instantiate_result != WASMER_OK)    
{    
    print_wasmer_error();    
    return -1;    
}    
wasmer_value_t arguments[] = {0};    
wasmer_value_t results[] = {0};    
// Call the `sum` function with the prepared arguments and the return value.    
wasmer_result_t call_result = wasmer_instance_call(instance, "_start", arguments, 0, results, 1);    
int response_value = results[0].value.I32;     
printf("%d\n", response_value);    
wasmer_instance_destroy(instance);    
return 0;    
}