GNUnet  0.19.3
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"
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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

int GNUNET_HELPER_kill (struct GNUNET_HELPER_Handle *h, int soft_kill)
 Sends termination signal to the helper process. More...
 
int 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, int 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 263 of file helper.c.

264 {
265  if (NULL != h->restart_task)
266  {
267  GNUNET_SCHEDULER_cancel (h->restart_task);
268  h->restart_task = NULL;
269  }
270  else
271  {
272  GNUNET_break (GNUNET_OK == GNUNET_HELPER_kill (h, soft_kill));
274  }
275 }
static struct GNUNET_ARM_Handle * h
Connection with ARM.
Definition: gnunet-arm.c:99
int GNUNET_HELPER_kill(struct GNUNET_HELPER_Handle *h, int soft_kill)
Sends termination signal to the helper process.
Definition: helper.c:167
int GNUNET_HELPER_wait(struct GNUNET_HELPER_Handle *h)
Reap the helper process.
Definition: helper.c:207
@ 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:975

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 447 of file helper.c.

448 {
449  struct GNUNET_HELPER_Handle *h = cls;
450 
451  h->restart_task = NULL;
452  h->retry_back_off++;
454  "Restarting helper with back-off %u\n",
455  h->retry_back_off);
456  start_helper (h);
457 }
#define GNUNET_log(kind,...)
@ GNUNET_ERROR_TYPE_INFO
static void start_helper(struct GNUNET_HELPER_Handle *h)
Start the helper process.
Definition: helper.c:383
The handle to a helper process.
Definition: helper.c:78

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 293 of file helper.c.

294 {
295  struct GNUNET_HELPER_Handle *h = cls;
297  ssize_t t;
298 
299  h->read_task = NULL;
300  t = GNUNET_DISK_file_read (h->fh_from_helper, &buf, sizeof(buf));
301  if (t < 0)
302  {
303  /* On read-error, restart the helper */
305  _ ("Error reading from `%s': %s\n"),
306  h->binary_name,
307  strerror (errno));
308  if (NULL != h->exp_cb)
309  {
310  h->exp_cb (h->cb_cls);
312  return;
313  }
315  /* Restart the helper */
316  h->restart_task = GNUNET_SCHEDULER_add_delayed (
318  h->retry_back_off),
319  &restart_task,
320  h);
321  return;
322  }
323  if (0 == t)
324  {
325  /* this happens if the helper is shut down via a
326  signal, so it is not a "hard" error */
328  "Got 0 bytes from helper `%s' (EOF)\n",
329  h->binary_name);
330  if (NULL != h->exp_cb)
331  {
332  h->exp_cb (h->cb_cls);
334  return;
335  }
337  /* Restart the helper */
338  h->restart_task = GNUNET_SCHEDULER_add_delayed (
340  h->retry_back_off),
341  &restart_task,
342  h);
343  return;
344  }
346  "Got %u bytes from helper `%s'\n",
347  (unsigned int) t,
348  h->binary_name);
350  h->fh_from_helper,
351  &helper_read,
352  h);
353  if (GNUNET_SYSERR ==
355  {
357  _ ("Failed to parse inbound message from helper `%s'\n"),
358  h->binary_name);
359  if (NULL != h->exp_cb)
360  {
361  h->exp_cb (h->cb_cls);
363  return;
364  }
366  /* Restart the helper */
367  h->restart_task = GNUNET_SCHEDULER_add_delayed (
369  h->retry_back_off),
370  &restart_task,
371  h);
372  return;
373  }
374 }
static char buf[2048]
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:621
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:537
#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:1656
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:1272
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:447
static void helper_read(void *cls)
Read from the helper-process.
Definition: helper.c:293
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:263
#define _(String)
GNU gettext support macro.
Definition: platform.h:177

References _, buf, 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, restart_task(), stop_helper(), and t.

Referenced by 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 383 of file helper.c.

384 {
385  h->helper_in =
387  h->helper_out =
389  if ((h->helper_in == NULL) || (h->helper_out == NULL))
390  {
391  /* out of file descriptors? try again later... */
393  "out of file descriptors? try again later\n");
395  h->restart_task = GNUNET_SCHEDULER_add_delayed (
397  h->retry_back_off),
398  &restart_task,
399  h);
400  return;
401  }
403  "Starting HELPER process `%s'\n",
404  h->binary_name);
405  h->fh_from_helper =
407  h->fh_to_helper =
409  h->helper_proc = GNUNET_OS_start_process_vap (h->with_control_pipe
413  h->helper_in,
414  h->helper_out,
415  NULL,
416  h->binary_name,
417  h->binary_argv);
418  if (NULL == h->helper_proc)
419  {
420  /* failed to start process? try again later... */
422  "failed to start process? try again later\n");
424  h->restart_task = GNUNET_SCHEDULER_add_delayed (
426  h->retry_back_off),
427  &restart_task,
428  h);
429  return;
430  }
433  if (NULL != h->mst)
435  h->fh_from_helper,
436  &helper_read,
437  h);
438 }
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:1615
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:1531
struct GNUNET_DISK_PipeHandle * GNUNET_DISK_pipe(enum GNUNET_DISK_PipeFlags pf)
Creates an interprocess channel.
Definition: disk.c:1441
@ 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:580
@ 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 551 of file helper.c.

552 {
553  struct GNUNET_HELPER_Handle *h = cls;
555  const char *buf;
556  ssize_t t;
557 
558  h->write_task = NULL;
559  if (NULL == (sh = h->sh_head))
560  {
561  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Helper write had no work!\n");
562  return; /* how did this happen? */
563  }
564  buf = (const char *) sh->msg;
565  t = GNUNET_DISK_file_write (h->fh_to_helper,
566  &buf[sh->wpos],
567  ntohs (sh->msg->size) - sh->wpos);
568  if (-1 == t)
569  {
570  /* On write-error, restart the helper */
572  _ ("Error writing to `%s': %s\n"),
573  h->binary_name,
574  strerror (errno));
575  if (NULL != h->exp_cb)
576  {
577  h->exp_cb (h->cb_cls);
579  return;
580  }
582  "Stopping and restarting helper task!\n");
584  /* Restart the helper */
585  h->restart_task = GNUNET_SCHEDULER_add_delayed (
587  h->retry_back_off),
588  &restart_task,
589  h);
590  return;
591  }
593  "Transmitted %u bytes to %s\n",
594  (unsigned int) t,
595  h->binary_name);
596  sh->wpos += t;
597  if (sh->wpos == ntohs (sh->msg->size))
598  {
599  GNUNET_CONTAINER_DLL_remove (h->sh_head, h->sh_tail, sh);
600  if (NULL != sh->cont)
601  sh->cont (sh->cont_cls, GNUNET_YES);
602  GNUNET_free (sh);
603  }
604  if (NULL != h->sh_head)
605  h->write_task =
607  h->fh_to_helper,
608  &helper_write,
609  h);
610 }
static struct SolverHandle * sh
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:685
#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:1689
static void helper_write(void *cls)
Write to the helper-process.
Definition: helper.c:551
Entry in the queue of messages we need to transmit to the helper.
Definition: helper.c:36

References _, buf, 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, restart_task(), sh, stop_helper(), and t.

Referenced by GNUNET_HELPER_send().

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