how sha256.lua call C function?

starofcore · 2017-07-17T11:59:35+00:00

Hi, I have a question about the openresty update.I'm using the ngx.shared.DICT as the cache backend for ngx_srcache.When updating OpenResty Linux Pa...

how sha256.lua call C function?

starofcore

in sha256.lua, C struct and funcions are declared:

typedef struct SHA256state_st
        {
        SHA_LONG h[8];
        SHA_LONG Nl,Nh;
        SHA_LONG data[SHA_LBLOCK];
        unsigned int num,md_len;
        } SHA256_CTX;

int SHA256_Init(SHA256_CTX *c);
int SHA256_Update(SHA256_CTX *c, const void *data, size_t len);
int SHA256_Final(unsigned char *md, SHA256_CTX *c);
]]

...

function _M.new(self)
    local ctx = ffi_new(ctx_ptr_type)
    if C.SHA256_Init(ctx) == 0 then
        return nil
    end

    return setmetatable({ _ctx = ctx }, mt)
end
I'm confused how luajit finds the location C funcions definded while no ffi.load() is used.
And how can I call some custom C function in default C namespace like above？
Thank you.

qleex001

~ % grep "int SHA256_Init" /usr/include/openssl/sha.h -n -A2
150:int SHA256_Init(SHA256_CTX *c);
151-int SHA256_Update(SHA256_CTX *c, const void *data, size_t len);
152-int SHA256_Final(unsigned char *md, SHA256_CTX *c);

Functions like SHA256_Init() is defined in openssl library, and had been loaded.

在 2017年7月17日星期一 UTC+8上午11:59:35，徐威远写道：

in sha256.lua, C struct and funcions are declared:
typedef struct SHA256state_st
{
SHA_LONG h[8];
SHA_LONG Nl,Nh;
SHA_LONG data[SHA_LBLOCK];
unsigned int num,md_len;
} SHA256_CTX;

int SHA256_Init(SHA256_CTX *c);
int SHA256_Update(SHA256_CTX *c, const void *data, size_t len);
int SHA256_Final(unsigned char *md, SHA256_CTX *c);
]]

...

function _M.new(self)
local ctx = ffi_new(ctx_ptr_type)
if C.SHA256_Init(ctx) == 0 then
return nil
end

return setmetatable({ _ctx = ctx }, mt)
end
I'm confused how luajit finds the location C funcions definded while no ffi.load() is used.
And how can I call some custom C function in default C namespace like above？
Thank you.

starofcore

Thanks for your help, I have found the functions defined in openssl-1.0.2k\crypto\evp\e_aes_cbc_hmac_sha256.c

but I still have no idea when and where openresty load them...

在 2017年7月17日星期一 UTC+8下午1:42:24，FQ Liu写道：

~ % grep "int SHA256_Init" /usr/include/openssl/sha.h -n -A2 150:int SHA256_Init(SHA256_CTX *c); 151-int SHA256_Update(SHA256_CTX *c, const void *data, size_t len); 152-int SHA256_Final(unsigned char *md, SHA256_CTX *c);

Functions like SHA256_Init() is defined in openssl library, and had been loaded.

在 2017年7月17日星期一 UTC+8上午11:59:35，徐威远写道：
in sha256.lua, C struct and funcions are declared:
typedef struct SHA256state_st
{
SHA_LONG h[8];
SHA_LONG Nl,Nh;
SHA_LONG data[SHA_LBLOCK];
unsigned int num,md_len;
} SHA256_CTX;

int SHA256_Init(SHA256_CTX *c);
int SHA256_Update(SHA256_CTX *c, const void *data, size_t len);
int SHA256_Final(unsigned char *md, SHA256_CTX *c);
]]

...

function _M.new(self)
local ctx = ffi_new(ctx_ptr_type)
if C.SHA256_Init(ctx) == 0 then
return nil
end

return setmetatable({ _ctx = ctx }, mt)
end
I'm confused how luajit finds the location C funcions definded while no ffi.load() is used.
And how can I call some custom C function in default C namespace like above？
Thank you.

qleex001

When nginx startup, linked library was automaticly loaded.

在 2017年7月17日星期一 UTC+8下午4:36:23，徐威远写道：

Thanks for your help, I have found the functions defined in openssl-1.0.2k\crypto\evp\e_aes_cbc_hmac_sha256.c
but I still have no idea when and where openresty load them...

在 2017年7月17日星期一 UTC+8下午1:42:24，FQ Liu写道：
~ % grep "int SHA256_Init" /usr/include/openssl/sha.h -n -A2 150:int SHA256_Init(SHA256_CTX *c); 151-int SHA256_Update(SHA256_CTX *c, const void *data, size_t len); 152-int SHA256_Final(unsigned char *md, SHA256_CTX *c);

Functions like SHA256_Init() is defined in openssl library, and had been loaded.

在 2017年7月17日星期一 UTC+8上午11:59:35，徐威远写道：
in sha256.lua, C struct and funcions are declared:
typedef struct SHA256state_st
{
SHA_LONG h[8];
SHA_LONG Nl,Nh;
SHA_LONG data[SHA_LBLOCK];
unsigned int num,md_len;
} SHA256_CTX;

int SHA256_Init(SHA256_CTX *c);
int SHA256_Update(SHA256_CTX *c, const void *data, size_t len);
int SHA256_Final(unsigned char *md, SHA256_CTX *c);
]]

...

function _M.new(self)
local ctx = ffi_new(ctx_ptr_type)
if C.SHA256_Init(ctx) == 0 then
return nil
end

return setmetatable({ _ctx = ctx }, mt)
end
I'm confused how luajit finds the location C funcions definded while no ffi.load() is used.
And how can I call some custom C function in default C namespace like above？
Thank you.