.. | ||
curl_wrapper | ||
examples | ||
.gitignore | ||
CMakeLists.txt | ||
README.md |
Curl Sandboxed
This library is a sandboxed version of curl's C API, libcurl, implemented using Sandboxed API.
Implementation details
All of libcurl's methods are supported by the library. However, a few of these have different signatures defined in the sandboxed header custom_curl.h
, which wraps and extends libcurl.
This is necessary because Sandboxed API sandboxes most of libcurl correctly, but encounters some issues when sandboxing a few methods. The simplest solution is wrapping these methods into wrapper methods that accomplish the same tasks but can also be sandboxed.
The next sections describe the issues encountered and contain some information on the signatures of the wrapper methods solving these issues.
Variadic methods
Variadic methods are currently not supported by Sandboxed API. To solve this, these methods are defined with an additional explicit parameter in custom_curl.h
.
The methods are:
curl_easy_setopt
. Usecurl_easy_setopt_ptr
,curl_easy_setopt_long
orcurl_easy_setopt_curl_off_t
instead.curl_easy_getinfo
. Usecurl_easy_getinfo_ptr
instead.curl_multi_setopt
. Usecurl_multi_setopt_ptr
,curl_multi_setopt_long
orcurl_multi_setopt_curl_off_t
instead.curl_share_setopt
. Usecurl_share_setopt_ptr
orcurl_share_setopt_long
instead
Methods with incomplete array arguments
Incomplete array arguments are currently not supported by Sandboxed API. To solve this, methods taking an incomplete array argument have a wrapper in custom_curl.h
, and take a pointer as the argument.
The methods are:
curl_multi_poll
. Usecurl_multi_poll_sapi
instead.curl_multi_wait
. Usecurl_multi_wait_sapi
instead.
Methods with conflicts on the generated header
Some methods create conflicts on the generated header because of redefined #define
directives from files included by the header. To solve this, the conflicting types and methods are redefined in custom_curl.h
.
The types are:
time_t
. Usetime_t_sapi
instead.fd_set
. Usefd_set_sapi
instead.
The methods are:
curl_getdate
. Usecurl_getdate_sapi
instead.curl_multi_fdset
. Usecurl_multi_fdset_sapi
instead.
Function pointers
The functions whose pointers will be passed to the library's methods (callbacks) can't be implemented in the files making use of the library, but must be in other files. These files must be compiled together with the library, and this is done by adding their absolute path to the cmake variable CURL_SAPI_CALLBACKS
.
The pointers can then be obtained using an RPCChannel
object, as shown in example2.cc
.
Examples
The examples
directory contains the sandboxed versions of example source codes taken from this page on curl's website. More information about each example can be found in the examples' README.
To build these examples when building the library, the cmake variable CURL_SAPI_ENABLE_EXAMPLES
must be set to ON
.
The callbacks.h
and callbacks.cc
files implement all the callbacks used by the examples.