GNUnet 0.21.1
helper.c File Reference

API for dealing with (SUID) helper processes that communicate via GNUNET_MessageHeaders on stdin/stdout. More...

#include "platform.h"
#include "gnunet_util_lib.h"
Include dependency graph for helper.c:

Go to the source code of this file.

Data Structures

struct  GNUNET_HELPER_SendHandle
 Entry in the queue of messages we need to transmit to the helper. More...
 
struct  GNUNET_HELPER_Handle
 The handle to a helper process. More...
 

Functions

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...
 
static void stop_helper (struct GNUNET_HELPER_Handle *h, int soft_kill)
 Stop the helper process, we're closing down or had an error. More...
 
static void restart_task (void *cls)
 Restart the helper process. More...
 
static void helper_read (void *cls)
 Read from the helper-process. More...
 
static void start_helper (struct GNUNET_HELPER_Handle *h)
 Start the helper process. More...
 
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...
 
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 and frees the handle. More...
 
static void helper_write (void *cls)
 Write to 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

API for dealing with (SUID) helper processes that communicate via GNUNET_MessageHeaders on stdin/stdout.

Author
Philipp Toelke
Christian Grothoff

Definition in file helper.c.

Function Documentation

◆ stop_helper()

static void stop_helper ( struct GNUNET_HELPER_Handle h,
int  soft_kill 
)
static

Stop the helper process, we're closing down or had an error.

Parameters
hhandle to the helper process
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 262 of file helper.c.

263{
264 if (NULL != h->restart_task)
265 {
266 GNUNET_SCHEDULER_cancel (h->restart_task);
267 h->restart_task = NULL;
268 }
269 else
270 {
271 GNUNET_break (GNUNET_OK == GNUNET_HELPER_kill (h, soft_kill));
273 }
274}
static struct GNUNET_ARM_Handle * h
Connection with ARM.
Definition: gnunet-arm.c:99
enum GNUNET_GenericReturnValue GNUNET_HELPER_wait(struct GNUNET_HELPER_Handle *h)
Reap the helper process.
Definition: helper.c:206
enum GNUNET_GenericReturnValue GNUNET_HELPER_kill(struct GNUNET_HELPER_Handle *h, int soft_kill)
Sends termination signal to the helper process.
Definition: helper.c:166
@ GNUNET_OK
#define GNUNET_break(cond)
Use this for internal assertion violations that are not fatal (can be handled) but should not occur.
void * GNUNET_SCHEDULER_cancel(struct GNUNET_SCHEDULER_Task *task)
Cancel the task with the specified identifier.
Definition: scheduler.c:981

References GNUNET_break, GNUNET_HELPER_kill(), GNUNET_HELPER_wait(), GNUNET_OK, GNUNET_SCHEDULER_cancel(), and h.

Referenced by GNUNET_HELPER_stop(), helper_read(), helper_write(), and start_helper().

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◆ restart_task()

static void restart_task ( void *  cls)
static

Restart the helper process.

Parameters
clshandle to the helper process

Definition at line 446 of file helper.c.

447{
448 struct GNUNET_HELPER_Handle *h = cls;
449
450 h->restart_task = NULL;
451 h->retry_back_off++;
453 "Restarting helper with back-off %u\n",
454 h->retry_back_off);
455 start_helper (h);
456}
#define GNUNET_log(kind,...)
@ GNUNET_ERROR_TYPE_INFO
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

References GNUNET_ERROR_TYPE_INFO, GNUNET_log, h, and start_helper().

Referenced by helper_read(), helper_write(), and start_helper().

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◆ helper_read()

static void helper_read ( void *  cls)
static

Read from the helper-process.

Parameters
clshandle to the helper process

Definition at line 292 of file helper.c.

293{
294 struct GNUNET_HELPER_Handle *h = cls;
296 ssize_t t;
297
298 h->read_task = NULL;
299 t = GNUNET_DISK_file_read (h->fh_from_helper, &buf, sizeof(buf));
300 if (t < 0)
301 {
302 /* On read-error, restart the helper */
304 _ ("Error reading from `%s': %s\n"),
305 h->binary_name,
306 strerror (errno));
307 if (NULL != h->exp_cb)
308 {
309 h->exp_cb (h->cb_cls);
311 return;
312 }
314 /* Restart the helper */
315 h->restart_task = GNUNET_SCHEDULER_add_delayed (
317 h->retry_back_off),
319 h);
320 return;
321 }
322 if (0 == t)
323 {
324 /* this happens if the helper is shut down via a
325 signal, so it is not a "hard" error */
327 "Got 0 bytes from helper `%s' (EOF)\n",
328 h->binary_name);
329 if (NULL != h->exp_cb)
330 {
331 h->exp_cb (h->cb_cls);
333 return;
334 }
336 /* Restart the helper */
337 h->restart_task = GNUNET_SCHEDULER_add_delayed (
339 h->retry_back_off),
341 h);
342 return;
343 }
345 "Got %u bytes from helper `%s'\n",
346 (unsigned int) t,
347 h->binary_name);
349 h->fh_from_helper,
351 h);
352 if (GNUNET_SYSERR ==
354 {
356 _ ("Failed to parse inbound message from helper `%s'\n"),
357 h->binary_name);
358 if (NULL != h->exp_cb)
359 {
360 h->exp_cb (h->cb_cls);
362 return;
363 }
365 /* Restart the helper */
366 h->restart_task = GNUNET_SCHEDULER_add_delayed (
368 h->retry_back_off),
370 h);
371 return;
372 }
373}
static struct GNUNET_SCHEDULER_Task * t
Main task.
#define GNUNET_MAX_MESSAGE_SIZE
Largest supported message (to be precise, one byte more than the largest possible message,...
ssize_t GNUNET_DISK_file_read(const struct GNUNET_DISK_FileHandle *h, void *result, size_t len)
Read the contents of a binary file into a buffer.
Definition: disk.c:622
void GNUNET_HELPER_stop(struct GNUNET_HELPER_Handle *h, int soft_kill)
Kills the helper, closes the pipe and frees the handle.
Definition: helper.c:536
#define GNUNET_ALIGN
gcc-ism to force alignment; we use this to align char-arrays that may then be cast to 'struct's.
@ GNUNET_NO
@ GNUNET_SYSERR
@ GNUNET_ERROR_TYPE_WARNING
@ GNUNET_ERROR_TYPE_DEBUG
struct GNUNET_SCHEDULER_Task * GNUNET_SCHEDULER_add_read_file(struct GNUNET_TIME_Relative delay, const struct GNUNET_DISK_FileHandle *rfd, 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:1662
struct GNUNET_SCHEDULER_Task * GNUNET_SCHEDULER_add_delayed(struct GNUNET_TIME_Relative delay, GNUNET_SCHEDULER_TaskCallback task, void *task_cls)
Schedule a new task to be run with a specified delay.
Definition: scheduler.c:1278
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
#define GNUNET_TIME_UNIT_FOREVER_REL
Constant used to specify "forever".
#define GNUNET_TIME_UNIT_SECONDS
One second.
struct GNUNET_TIME_Relative GNUNET_TIME_relative_multiply(struct GNUNET_TIME_Relative rel, unsigned long long factor)
Multiply relative time by a given factor.
Definition: time.c:484
static void restart_task(void *cls)
Restart the helper process.
Definition: helper.c:446
static void helper_read(void *cls)
Read from the helper-process.
Definition: helper.c:292
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
#define _(String)
GNU gettext support macro.
Definition: platform.h:178

References _, GNUNET_ALIGN, GNUNET_DISK_file_read(), GNUNET_ERROR_TYPE_DEBUG, GNUNET_ERROR_TYPE_WARNING, GNUNET_HELPER_stop(), GNUNET_log, GNUNET_MAX_MESSAGE_SIZE, GNUNET_MST_from_buffer(), GNUNET_NO, GNUNET_SCHEDULER_add_delayed(), GNUNET_SCHEDULER_add_read_file(), GNUNET_SYSERR, GNUNET_TIME_relative_multiply(), GNUNET_TIME_UNIT_FOREVER_REL, GNUNET_TIME_UNIT_SECONDS, h, helper_read(), restart_task(), stop_helper(), and t.

Referenced by helper_read(), and start_helper().

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◆ start_helper()

static void start_helper ( struct GNUNET_HELPER_Handle h)
static

Start the helper process.

Parameters
hhandle to the helper process

Definition at line 382 of file helper.c.

383{
384 h->helper_in =
386 h->helper_out =
388 if ((h->helper_in == NULL) || (h->helper_out == NULL))
389 {
390 /* out of file descriptors? try again later... */
392 "out of file descriptors? try again later\n");
394 h->restart_task = GNUNET_SCHEDULER_add_delayed (
396 h->retry_back_off),
398 h);
399 return;
400 }
402 "Starting HELPER process `%s'\n",
403 h->binary_name);
404 h->fh_from_helper =
406 h->fh_to_helper =
408 h->helper_proc = GNUNET_OS_start_process_vap (h->with_control_pipe
412 h->helper_in,
413 h->helper_out,
414 NULL,
415 h->binary_name,
416 h->binary_argv);
417 if (NULL == h->helper_proc)
418 {
419 /* failed to start process? try again later... */
421 "failed to start process? try again later\n");
423 h->restart_task = GNUNET_SCHEDULER_add_delayed (
425 h->retry_back_off),
427 h);
428 return;
429 }
432 if (NULL != h->mst)
434 h->fh_from_helper,
436 h);
437}
const struct GNUNET_DISK_FileHandle * GNUNET_DISK_pipe_handle(const struct GNUNET_DISK_PipeHandle *p, enum GNUNET_DISK_PipeEnd n)
Get the handle to a particular pipe end.
Definition: disk.c:1617
struct GNUNET_DISK_PipeHandle * GNUNET_DISK_pipe(enum GNUNET_DISK_PipeFlags pf)
Creates an interprocess channel.
Definition: disk.c:1444
enum GNUNET_GenericReturnValue GNUNET_DISK_pipe_close_end(struct GNUNET_DISK_PipeHandle *p, enum GNUNET_DISK_PipeEnd end)
Closes one half of an interprocess channel.
Definition: disk.c:1534
@ GNUNET_DISK_PF_BLOCKING_RW
Configure both pipe ends for blocking operations if set.
@ GNUNET_DISK_PIPE_END_WRITE
The writing-end of a pipe.
@ GNUNET_DISK_PIPE_END_READ
The reading-end of a pipe.
struct GNUNET_OS_Process * GNUNET_OS_start_process_vap(enum GNUNET_OS_InheritStdioFlags std_inheritance, struct GNUNET_DISK_PipeHandle *pipe_stdin, struct GNUNET_DISK_PipeHandle *pipe_stdout, struct GNUNET_DISK_PipeHandle *pipe_stderr, const char *filename, char *const argv[])
Start a process.
Definition: os_priority.c:573
@ GNUNET_OS_INHERIT_STD_ERR
When this flag is set, the child process will inherit stderr of the parent.
Definition: gnunet_os_lib.h:95
@ GNUNET_OS_USE_PIPE_CONTROL
Should a pipe be used to send signals to the child?

References GNUNET_DISK_PF_BLOCKING_RW, GNUNET_DISK_pipe(), GNUNET_DISK_pipe_close_end(), GNUNET_DISK_PIPE_END_READ, GNUNET_DISK_PIPE_END_WRITE, GNUNET_DISK_pipe_handle(), GNUNET_ERROR_TYPE_DEBUG, GNUNET_ERROR_TYPE_WARNING, GNUNET_log, GNUNET_NO, GNUNET_OS_INHERIT_STD_ERR, GNUNET_OS_start_process_vap(), GNUNET_OS_USE_PIPE_CONTROL, GNUNET_SCHEDULER_add_delayed(), GNUNET_SCHEDULER_add_read_file(), GNUNET_TIME_relative_multiply(), GNUNET_TIME_UNIT_FOREVER_REL, GNUNET_TIME_UNIT_SECONDS, h, helper_read(), restart_task(), and stop_helper().

Referenced by GNUNET_HELPER_start(), and restart_task().

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◆ helper_write()

static void helper_write ( void *  cls)
static

Write to the helper-process.

Parameters
clshandle to the helper process

Definition at line 550 of file helper.c.

551{
552 struct GNUNET_HELPER_Handle *h = cls;
554 const char *buf;
555 ssize_t t;
556
557 h->write_task = NULL;
558 if (NULL == (sh = h->sh_head))
559 {
560 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Helper write had no work!\n");
561 return; /* how did this happen? */
562 }
563 buf = (const char *) sh->msg;
564 t = GNUNET_DISK_file_write (h->fh_to_helper,
565 &buf[sh->wpos],
566 ntohs (sh->msg->size) - sh->wpos);
567 if (-1 == t)
568 {
569 /* On write-error, restart the helper */
571 _ ("Error writing to `%s': %s\n"),
572 h->binary_name,
573 strerror (errno));
574 if (NULL != h->exp_cb)
575 {
576 h->exp_cb (h->cb_cls);
578 return;
579 }
581 "Stopping and restarting helper task!\n");
583 /* Restart the helper */
584 h->restart_task = GNUNET_SCHEDULER_add_delayed (
586 h->retry_back_off),
588 h);
589 return;
590 }
592 "Transmitted %u bytes to %s\n",
593 (unsigned int) t,
594 h->binary_name);
595 sh->wpos += t;
596 if (sh->wpos == ntohs (sh->msg->size))
597 {
598 GNUNET_CONTAINER_DLL_remove (h->sh_head, h->sh_tail, sh);
599 if (NULL != sh->cont)
600 sh->cont (sh->cont_cls, GNUNET_YES);
601 GNUNET_free (sh);
602 }
603 if (NULL != h->sh_head)
604 h->write_task =
606 h->fh_to_helper,
608 h);
609}
static struct GNUNET_IDENTITY_Handle * sh
Handle to IDENTITY service.
ssize_t GNUNET_DISK_file_write(const struct GNUNET_DISK_FileHandle *h, const void *buffer, size_t n)
Write a buffer to a file.
Definition: disk.c:686
#define GNUNET_CONTAINER_DLL_remove(head, tail, element)
Remove an element from a DLL.
@ GNUNET_YES
#define GNUNET_free(ptr)
Wrapper around free.
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:1695
static void helper_write(void *cls)
Write to the helper-process.
Definition: helper.c:550
Entry in the queue of messages we need to transmit to the helper.
Definition: helper.c:35

References _, GNUNET_CONTAINER_DLL_remove, GNUNET_DISK_file_write(), GNUNET_ERROR_TYPE_DEBUG, GNUNET_ERROR_TYPE_WARNING, GNUNET_free, GNUNET_HELPER_stop(), GNUNET_log, GNUNET_NO, GNUNET_SCHEDULER_add_delayed(), GNUNET_SCHEDULER_add_write_file(), GNUNET_TIME_relative_multiply(), GNUNET_TIME_UNIT_FOREVER_REL, GNUNET_TIME_UNIT_SECONDS, GNUNET_YES, h, helper_write(), restart_task(), sh, stop_helper(), and t.

Referenced by GNUNET_HELPER_send(), and helper_write().

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