GNUnet 0.22.1
Helper library

Dealing with SUID helper processes. More...

Collaboration diagram for Helper library:

Typedefs

typedef void(* GNUNET_HELPER_ExceptionCallback) (void *cls)
 Callback that will be called when the helper process dies. More...
 
typedef void(* GNUNET_HELPER_Continuation) (void *cls, enum GNUNET_GenericReturnValue result)
 Continuation function. More...
 

Functions

struct GNUNET_HELPER_HandleGNUNET_HELPER_start (int with_control_pipe, const char *binary_name, char *const binary_argv[], GNUNET_MessageTokenizerCallback cb, GNUNET_HELPER_ExceptionCallback exp_cb, void *cb_cls)
 Starts a helper and begins reading from it. More...
 
enum GNUNET_GenericReturnValue GNUNET_HELPER_kill (struct GNUNET_HELPER_Handle *h, int soft_kill)
 Sends termination signal to the helper process. More...
 
enum GNUNET_GenericReturnValue GNUNET_HELPER_wait (struct GNUNET_HELPER_Handle *h)
 Reap the helper process. More...
 
void GNUNET_HELPER_destroy (struct GNUNET_HELPER_Handle *h)
 Free's the resources occupied by the helper handle. More...
 
void GNUNET_HELPER_stop (struct GNUNET_HELPER_Handle *h, int soft_kill)
 Kills the helper, closes the pipe, frees the handle and calls wait() on the helper process. More...
 
struct GNUNET_HELPER_SendHandleGNUNET_HELPER_send (struct GNUNET_HELPER_Handle *h, const struct GNUNET_MessageHeader *msg, bool can_drop, GNUNET_HELPER_Continuation cont, void *cont_cls)
 Send an message to the helper. More...
 
void GNUNET_HELPER_send_cancel (struct GNUNET_HELPER_SendHandle *sh)
 Cancel a GNUNET_HELPER_send operation. More...
 

Detailed Description

Dealing with SUID helper processes.

Provides an API for dealing with (SUID) helper processes that communicate via GNUNET_MessageHeaders on STDIN/STDOUT.

Typedef Documentation

◆ GNUNET_HELPER_ExceptionCallback

typedef void(* GNUNET_HELPER_ExceptionCallback) (void *cls)

Callback that will be called when the helper process dies.

This is not called when the helper process is stopped using GNUNET_HELPER_stop()

Parameters
clsthe closure from GNUNET_HELPER_start()

Definition at line 64 of file gnunet_helper_lib.h.

◆ GNUNET_HELPER_Continuation

typedef void(* GNUNET_HELPER_Continuation) (void *cls, enum GNUNET_GenericReturnValue result)

Continuation function.

Parameters
clsclosure
resultGNUNET_OK on success, GNUNET_NO if helper process died GNUNET_SYSERR during GNUNET_HELPER_destroy

Definition at line 148 of file gnunet_helper_lib.h.

Function Documentation

◆ GNUNET_HELPER_start()

struct GNUNET_HELPER_Handle * GNUNET_HELPER_start ( int  with_control_pipe,
const char *  binary_name,
char *const  binary_argv[],
GNUNET_MessageTokenizerCallback  cb,
GNUNET_HELPER_ExceptionCallback  exp_cb,
void *  cb_cls 
)

Starts a helper and begins reading from it.

The helper process is restarted when it dies except when it is stopped using GNUNET_HELPER_stop() or when the exp_cb callback is not NULL.

Parameters
with_control_pipedoes the helper support the use of a control pipe for signalling?
binary_namename of the binary to run
binary_argvNULL-terminated list of arguments to give when starting the binary (this argument must not be modified by the client for the lifetime of the helper handle)
cbfunction to call if we get messages from the helper
exp_cbthe exception callback to call. Set this to NULL if the helper process has to be restarted automatically when it dies/crashes
cb_clsclosure for the above callbacks
Returns
the new Handle, NULL on error

Definition at line 460 of file helper.c.

466{
467 struct GNUNET_HELPER_Handle *h;
468 unsigned int c;
469
471 h->with_control_pipe = with_control_pipe;
472 /* Lookup in libexec path only if we are starting gnunet helpers */
473 if (NULL != strstr (binary_name, "gnunet"))
475 else
476 h->binary_name = GNUNET_strdup (binary_name);
477 for (c = 0; NULL != binary_argv[c]; c++)
478 ;
479 h->binary_argv = GNUNET_malloc (sizeof(char *) * (c + 1));
480 for (c = 0; NULL != binary_argv[c]; c++)
481 h->binary_argv[c] = GNUNET_strdup (binary_argv[c]);
482 h->binary_argv[c] = NULL;
483 h->cb_cls = cb_cls;
484 if (NULL != cb)
485 h->mst = GNUNET_MST_create (cb, h->cb_cls);
486 h->exp_cb = exp_cb;
487 h->retry_back_off = 0;
488 start_helper (h);
489 return h;
490}
static struct GNUNET_ARM_Handle * h
Connection with ARM.
Definition: gnunet-arm.c:98
#define GNUNET_strdup(a)
Wrapper around GNUNET_xstrdup_.
#define GNUNET_new(type)
Allocate a struct or union of the given type.
#define GNUNET_malloc(size)
Wrapper around malloc.
char * GNUNET_OS_get_libexec_binary_path(const char *progname)
Given the name of a gnunet-helper, gnunet-service or gnunet-daemon binary, try to prefix it with the ...
struct GNUNET_MessageStreamTokenizer * GNUNET_MST_create(GNUNET_MessageTokenizerCallback cb, void *cb_cls)
Create a message stream tokenizer.
Definition: mst.c:86
static void start_helper(struct GNUNET_HELPER_Handle *h)
Start the helper process.
Definition: helper.c:382
The handle to a helper process.
Definition: helper.c:77
int with_control_pipe
Does the helper support the use of a control pipe for signalling?
Definition: helper.c:156
void * cb_cls
The closure for callbacks.
Definition: helper.c:116
char ** binary_argv
NULL-terminated list of command-line arguments.
Definition: helper.c:136
char * binary_name
Binary to run.
Definition: helper.c:131
static void exp_cb(void *cls)
Callback called if there was an exception during execution of the helper.

References GNUNET_HELPER_Handle::binary_argv, GNUNET_HELPER_Handle::binary_name, GNUNET_HELPER_Handle::cb_cls, exp_cb(), GNUNET_malloc, GNUNET_MST_create(), GNUNET_new, GNUNET_OS_get_libexec_binary_path(), GNUNET_strdup, h, start_helper(), and GNUNET_HELPER_Handle::with_control_pipe.

Referenced by enable(), GNUNET_FS_directory_scan_start(), run(), and start_helper().

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◆ GNUNET_HELPER_kill()

enum GNUNET_GenericReturnValue GNUNET_HELPER_kill ( struct GNUNET_HELPER_Handle h,
int  soft_kill 
)

Sends termination signal to the helper process.

The helper process is not reaped; call GNUNET_HELPER_wait() for reaping the dead helper process.

Parameters
hthe helper handle
soft_killif GNUNET_YES, signals termination by closing the helper's stdin; GNUNET_NO to signal termination by sending SIGTERM to helper
Returns
GNUNET_OK on success; GNUNET_SYSERR on error

Definition at line 166 of file helper.c.

167{
169 int ret;
170
171 while (NULL != (sh = h->sh_head))
172 {
173 GNUNET_CONTAINER_DLL_remove (h->sh_head, h->sh_tail, sh);
174 if (NULL != sh->cont)
175 sh->cont (sh->cont_cls, GNUNET_NO);
176 GNUNET_free (sh);
177 }
178 if (NULL != h->restart_task)
179 {
180 GNUNET_SCHEDULER_cancel (h->restart_task);
181 h->restart_task = NULL;
182 }
183 if (NULL != h->read_task)
184 {
185 GNUNET_SCHEDULER_cancel (h->read_task);
186 h->read_task = NULL;
187 }
188 if (NULL == h->helper_proc)
189 return GNUNET_SYSERR;
190 if (GNUNET_YES == soft_kill)
191 {
192 /* soft-kill only possible with pipes */
193 GNUNET_assert (NULL != h->helper_in);
194 ret = GNUNET_DISK_pipe_close (h->helper_in);
195 h->helper_in = NULL;
196 h->fh_to_helper = NULL;
197 return ret;
198 }
199 if (0 != GNUNET_OS_process_kill (h->helper_proc, GNUNET_TERM_SIG))
200 return GNUNET_SYSERR;
201 return GNUNET_OK;
202}
static int ret
Final status code.
Definition: gnunet-arm.c:93
static struct GNUNET_IDENTITY_Handle * sh
Handle to IDENTITY service.
enum GNUNET_GenericReturnValue GNUNET_DISK_pipe_close(struct GNUNET_DISK_PipeHandle *p)
Closes an interprocess channel.
Definition: disk.c:1588
#define GNUNET_CONTAINER_DLL_remove(head, tail, element)
Remove an element from a DLL.
@ GNUNET_OK
@ GNUNET_YES
@ GNUNET_NO
@ GNUNET_SYSERR
#define GNUNET_assert(cond)
Use this for fatal errors that cannot be handled.
#define GNUNET_free(ptr)
Wrapper around free.
int GNUNET_OS_process_kill(struct GNUNET_OS_Process *proc, int sig)
Sends a signal to the process.
Definition: os_priority.c:210
void * GNUNET_SCHEDULER_cancel(struct GNUNET_SCHEDULER_Task *task)
Cancel the task with the specified identifier.
Definition: scheduler.c:979
#define GNUNET_TERM_SIG
The termination signal.
Definition: platform.h:234
Entry in the queue of messages we need to transmit to the helper.
Definition: helper.c:35

References GNUNET_assert, GNUNET_CONTAINER_DLL_remove, GNUNET_DISK_pipe_close(), GNUNET_free, GNUNET_NO, GNUNET_OK, GNUNET_OS_process_kill(), GNUNET_SCHEDULER_cancel(), GNUNET_SYSERR, GNUNET_TERM_SIG, GNUNET_YES, h, ret, and sh.

Referenced by cleanup(), disable(), and stop_helper().

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◆ GNUNET_HELPER_wait()

enum GNUNET_GenericReturnValue GNUNET_HELPER_wait ( struct GNUNET_HELPER_Handle h)

Reap the helper process.

This call is blocking (!). The helper process should either be sent a termination signal before or should be dead before calling this function

Parameters
hthe helper handle
Returns
GNUNET_OK on success; GNUNET_SYSERR on error

Definition at line 206 of file helper.c.

207{
209 int ret;
210
212 if (NULL != h->helper_proc)
213 {
214 ret = GNUNET_OS_process_wait (h->helper_proc);
215 GNUNET_OS_process_destroy (h->helper_proc);
216 h->helper_proc = NULL;
217 }
218 if (NULL != h->read_task)
219 {
220 GNUNET_SCHEDULER_cancel (h->read_task);
221 h->read_task = NULL;
222 }
223 if (NULL != h->write_task)
224 {
225 GNUNET_SCHEDULER_cancel (h->write_task);
226 h->write_task = NULL;
227 }
228 if (NULL != h->helper_in)
229 {
230 GNUNET_DISK_pipe_close (h->helper_in);
231 h->helper_in = NULL;
232 h->fh_to_helper = NULL;
233 }
234 if (NULL != h->helper_out)
235 {
236 GNUNET_DISK_pipe_close (h->helper_out);
237 h->helper_out = NULL;
238 h->fh_from_helper = NULL;
239 }
240 while (NULL != (sh = h->sh_head))
241 {
242 GNUNET_CONTAINER_DLL_remove (h->sh_head, h->sh_tail, sh);
243 if (NULL != sh->cont)
244 sh->cont (sh->cont_cls, GNUNET_NO);
245 GNUNET_free (sh);
246 }
247 /* purge MST buffer */
248 if (NULL != h->mst)
249 (void) GNUNET_MST_from_buffer (h->mst, NULL, 0, GNUNET_YES, GNUNET_NO);
250 return ret;
251}
void GNUNET_OS_process_destroy(struct GNUNET_OS_Process *proc)
Cleans up process structure contents (OS-dependent) and deallocates it.
Definition: os_priority.c:260
enum GNUNET_GenericReturnValue GNUNET_OS_process_wait(struct GNUNET_OS_Process *proc)
Wait for a process to terminate.
Definition: os_priority.c:878
enum GNUNET_GenericReturnValue GNUNET_MST_from_buffer(struct GNUNET_MessageStreamTokenizer *mst, const char *buf, size_t size, int purge, int one_shot)
Add incoming data to the receive buffer and call the callback for all complete messages.
Definition: mst.c:101

References GNUNET_CONTAINER_DLL_remove, GNUNET_DISK_pipe_close(), GNUNET_free, GNUNET_MST_from_buffer(), GNUNET_NO, GNUNET_OS_process_destroy(), GNUNET_OS_process_wait(), GNUNET_SCHEDULER_cancel(), GNUNET_SYSERR, GNUNET_YES, h, ret, and sh.

Referenced by cleanup(), and stop_helper().

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◆ GNUNET_HELPER_destroy()

void GNUNET_HELPER_destroy ( struct GNUNET_HELPER_Handle h)

Free's the resources occupied by the helper handle.

Parameters
hthe helper handle to free

Definition at line 499 of file helper.c.

500{
501 unsigned int c;
503
504 if (NULL != h->write_task)
505 {
506 GNUNET_SCHEDULER_cancel (h->write_task);
507 h->write_task = NULL;
508 }
509 GNUNET_assert (NULL == h->read_task);
510 GNUNET_assert (NULL == h->restart_task);
511 while (NULL != (sh = h->sh_head))
512 {
513 GNUNET_CONTAINER_DLL_remove (h->sh_head, h->sh_tail, sh);
514 if (NULL != sh->cont)
515 sh->cont (sh->cont_cls, GNUNET_SYSERR);
516 GNUNET_free (sh);
517 }
518 if (NULL != h->mst)
519 GNUNET_MST_destroy (h->mst);
520 GNUNET_free (h->binary_name);
521 for (c = 0; h->binary_argv[c] != NULL; c++)
522 GNUNET_free (h->binary_argv[c]);
523 GNUNET_free (h->binary_argv);
524 GNUNET_free (h);
525}
void GNUNET_MST_destroy(struct GNUNET_MessageStreamTokenizer *mst)
Destroys a tokenizer.
Definition: mst.c:404

References GNUNET_assert, GNUNET_CONTAINER_DLL_remove, GNUNET_free, GNUNET_MST_destroy(), GNUNET_SCHEDULER_cancel(), GNUNET_SYSERR, h, and sh.

Referenced by disable(), and GNUNET_HELPER_stop().

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◆ GNUNET_HELPER_stop()

void GNUNET_HELPER_stop ( struct GNUNET_HELPER_Handle h,
int  soft_kill 
)

Kills the helper, closes the pipe, frees the handle and calls wait() on the helper process.

Parameters
hhandle to helper to stop
soft_killif GNUNET_YES, signals termination by closing the helper's stdin; GNUNET_NO to signal termination by sending SIGTERM to helper

Kills the helper, closes the pipe, frees the handle and calls wait() on the helper process.

Parameters
hhandle to helper to stop
soft_killif GNUNET_YES, signals termination by closing the helper's stdin; GNUNET_NO to signal termination by sending SIGTERM to helper

Definition at line 536 of file helper.c.

537{
538 h->exp_cb = NULL;
539 stop_helper (h, soft_kill);
541}
void GNUNET_HELPER_destroy(struct GNUNET_HELPER_Handle *h)
Free's the resources occupied by the helper handle.
Definition: helper.c:499
static void stop_helper(struct GNUNET_HELPER_Handle *h, int soft_kill)
Stop the helper process, we're closing down or had an error.
Definition: helper.c:262

References GNUNET_HELPER_destroy(), h, and stop_helper().

Referenced by cleanup(), cleanup_task(), finish_scan(), GNUNET_FS_directory_scan_abort(), handle_helper_local_finished(), helper_read(), helper_write(), and netjail_exec_cleanup().

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◆ GNUNET_HELPER_send()

struct GNUNET_HELPER_SendHandle * GNUNET_HELPER_send ( struct GNUNET_HELPER_Handle h,
const struct GNUNET_MessageHeader msg,
bool  can_drop,
GNUNET_HELPER_Continuation  cont,
void *  cont_cls 
)

Send an message to the helper.

Parameters
hhelper to send message to
msgmessage to send
can_dropcan the message be dropped if there is already one in the queue?
contcontinuation to run once the message is out (GNUNET_OK on success, GNUNET_NO if the helper process died, GNUNET_SYSERR during GNUNET_HELPER_destroy).
cont_clsclosure for cont
Returns
NULL if the message was dropped, otherwise handle to cancel cont (actual transmission may not be abortable)

Definition at line 613 of file helper.c.

618{
620 uint16_t mlen;
621
622 if (NULL == h->fh_to_helper)
623 return NULL;
624 if (can_drop && (NULL != h->sh_head))
625 return NULL;
626 mlen = ntohs (msg->size);
627 sh = GNUNET_malloc (sizeof(struct GNUNET_HELPER_SendHandle) + mlen);
628 sh->msg = (const struct GNUNET_MessageHeader *) &sh[1];
629 GNUNET_memcpy (&sh[1], msg, mlen);
630 sh->h = h;
631 sh->cont = cont;
632 sh->cont_cls = cont_cls;
633 GNUNET_CONTAINER_DLL_insert_tail (h->sh_head, h->sh_tail, sh);
634 if (NULL == h->write_task)
635 h->write_task =
637 h->fh_to_helper,
639 h);
640
641 return sh;
642}
struct GNUNET_MessageHeader * msg
Definition: 005.c:2
#define GNUNET_CONTAINER_DLL_insert_tail(head, tail, element)
Insert an element at the tail of a DLL.
#define GNUNET_memcpy(dst, src, n)
Call memcpy() but check for n being 0 first.
uint16_t size
The length of the struct (in bytes, including the length field itself), in big-endian format.
struct GNUNET_SCHEDULER_Task * GNUNET_SCHEDULER_add_write_file(struct GNUNET_TIME_Relative delay, const struct GNUNET_DISK_FileHandle *wfd, GNUNET_SCHEDULER_TaskCallback task, void *task_cls)
Schedule a new task to be run with a specified delay or when the specified file descriptor is ready f...
Definition: scheduler.c:1693
#define GNUNET_TIME_UNIT_FOREVER_REL
Constant used to specify "forever".
static void helper_write(void *cls)
Write to the helper-process.
Definition: helper.c:550
Header for all communications.

References GNUNET_CONTAINER_DLL_insert_tail, GNUNET_malloc, GNUNET_memcpy, GNUNET_SCHEDULER_add_write_file(), GNUNET_TIME_UNIT_FOREVER_REL, h, helper_write(), msg, sh, and GNUNET_MessageHeader::size.

Referenced by GNUNET_TESTING_loop_notify_children_(), handle_icmp_back(), handle_tcp_back(), handle_udp_back(), play(), request_done(), send_icmp_packet_via_tun(), send_start_messages(), send_tcp_packet_via_tun(), and send_udp_packet_via_tun().

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◆ GNUNET_HELPER_send_cancel()

void GNUNET_HELPER_send_cancel ( struct GNUNET_HELPER_SendHandle sh)

Cancel a GNUNET_HELPER_send operation.

If possible, transmitting the message is also aborted, but at least 'cont' won't be called.

Parameters
shoperation to cancel

Definition at line 653 of file helper.c.

654{
655 struct GNUNET_HELPER_Handle *h = sh->h;
656
657 sh->cont = NULL;
658 sh->cont_cls = NULL;
659 if (0 == sh->wpos)
660 {
661 GNUNET_CONTAINER_DLL_remove (h->sh_head, h->sh_tail, sh);
662 GNUNET_free (sh);
663 if (NULL == h->sh_head)
664 {
665 GNUNET_SCHEDULER_cancel (h->write_task);
666 h->write_task = NULL;
667 }
668 }
669}

References GNUNET_CONTAINER_DLL_remove, GNUNET_free, GNUNET_SCHEDULER_cancel(), h, and sh.

Referenced by finish_test().

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