extractor_plugin_main.c File Reference

main loop for an out-of-process plugin More...

#include "platform.h"
#include "extractor.h"
#include "extractor_common.h"
#include "extractor_datasource.h"
#include "extractor_plugins.h"
#include "extractor_ipc.h"
#include "extractor_logging.h"
#include "extractor_plugin_main.h"
#include <dirent.h>
#include <sys/types.h>

Include dependency graph for extractor_plugin_main.c:

Go to the source code of this file.

Data Structures
struct	ProcessingContext

Macros
#define	SHM_ID   int
#define	INVALID_SHM_ID   -1

Functions
static int64_t	plugin_env_seek (void *cls, int64_t pos, int whence)
static ssize_t	plugin_env_read (void *cls, void **data, size_t count)
static uint64_t	plugin_env_get_size (void *cls)
static int	plugin_env_send_proc (void *cls, const char *plugin_name, enum EXTRACTOR_MetaType type, enum EXTRACTOR_MetaFormat format, const char *data_mime_type, const char *data, size_t data_len)
static int	handle_init_message (struct ProcessingContext *pc)
static int	handle_start_message (struct ProcessingContext *pc)
static void	process_requests (struct ProcessingContext *pc)
static void	open_dev_null (int target_fd, int flags)
void	EXTRACTOR_plugin_main_ (struct EXTRACTOR_PluginList *plugin, int in, int out)

Detailed Description

main loop for an out-of-process plugin

Author

Christian Grothoff

Definition in file extractor_plugin_main.c.

Macro Definition Documentation

INVALID_SHM_ID

#define INVALID_SHM_ID   -1

Definition at line 46 of file extractor_plugin_main.c.

SHM_ID

#define SHM_ID   int

Definition at line 45 of file extractor_plugin_main.c.

Function Documentation

EXTRACTOR_plugin_main_()

void EXTRACTOR_plugin_main_	(	struct EXTRACTOR_PluginList *	plugin,
		int	in,
		int	out
	)

'main' function of the child process. Loads the plugin, sets up its in and out pipes, then runs the request serving function.

Parameters

plugin	extractor plugin to use
in	stream to read from
out	stream to write to

Definition at line 606 of file extractor_plugin_main.c.

References EXTRACTOR_plugin_load_(), ProcessingContext::in, INVALID_SHM_ID, LOG, LOG_STRERROR, NULL, open_dev_null(), ProcessingContext::out, ProcessingContext::plugin, process_requests(), ProcessingContext::shm, ProcessingContext::shm_id, ProcessingContext::shm_map_size, EXTRACTOR_PluginList::short_libname, and EXTRACTOR_PluginList::specials.

Referenced by EXTRACTOR_IPC_channel_create_().

handle_init_message()

static int handle_init_message ( struct ProcessingContext *  pc )

static

Handle an init message. The opcode itself has already been read.

Parameters

pc	processing context

Returns

0 on success, -1 on error

Definition at line 382 of file extractor_plugin_main.c.

References EXTRACTOR_read_all_(), ProcessingContext::in, LOG, LOG_STRERROR_FILE, MAX_SHM_NAME, MESSAGE_INIT_STATE, NULL, InitMessage::opcode, InitMessage::reserved, ProcessingContext::shm, ProcessingContext::shm_id, InitMessage::shm_map_size, ProcessingContext::shm_map_size, and InitMessage::shm_name_length.

Referenced by process_requests().

handle_start_message()

static int handle_start_message ( struct ProcessingContext *  pc )

static

Handle a start message. The opcode itself has already been read.

Parameters

pc	processing context

Returns

0 on success, -1 on error

Definition at line 461 of file extractor_plugin_main.c.

References EXTRACTOR_ExtractContext::cls, EXTRACTOR_ExtractContext::config, EXTRACTOR_PluginList::extract_method, EXTRACTOR_read_all_(), EXTRACTOR_write_all_(), StartMessage::file_size, ProcessingContext::file_size, EXTRACTOR_ExtractContext::get_size, ProcessingContext::in, LOG, MESSAGE_DONE, MESSAGE_EXTRACT_START, NULL, StartMessage::opcode, ProcessingContext::out, ProcessingContext::plugin, plugin_env_get_size(), plugin_env_read(), plugin_env_seek(), plugin_env_send_proc(), EXTRACTOR_PluginList::plugin_options, EXTRACTOR_ExtractContext::proc, EXTRACTOR_ExtractContext::read, ProcessingContext::read_position, StartMessage::reserved, EXTRACTOR_ExtractContext::seek, ProcessingContext::shm_off, StartMessage::shm_ready_bytes, ProcessingContext::shm_ready_bytes, and EXTRACTOR_PluginList::specials.

Referenced by process_requests().

open_dev_null()

static void open_dev_null ( int  target_fd, int  flags  )

static

Open '/dev/null' and make the result the given file descriptor.

Parameters

target_fd	desired FD to point to /dev/null
flags	open flags (O_RDONLY, O_WRONLY)

Definition at line 568 of file extractor_plugin_main.c.

References LOG_STRERROR, and LOG_STRERROR_FILE.

Referenced by EXTRACTOR_plugin_main_().

plugin_env_get_size()

static uint64_t plugin_env_get_size ( void *  cls )

static

Provide the overall file size to plugins.

Parameters

cls	the 'struct ProcessingContext'

Returns

overall file size of the current file

Definition at line 291 of file extractor_plugin_main.c.

References ProcessingContext::file_size.

Referenced by handle_start_message().

plugin_env_read()

static ssize_t plugin_env_read ( void *  cls, void **  data, size_t  count  )

static

Fills data with a pointer to the data buffer.

Parameters

plugin	plugin context
data	location to store data pointer
count	number of bytes to read

Returns

number of bytes (<= count) available in data, -1 on error

Definition at line 256 of file extractor_plugin_main.c.

References ProcessingContext::file_size, LOG, NULL, plugin_env_seek(), ProcessingContext::read_position, ProcessingContext::shm, ProcessingContext::shm_off, and ProcessingContext::shm_ready_bytes.

Referenced by handle_start_message().

plugin_env_seek()

static int64_t plugin_env_seek ( void *  cls, int64_t  pos, int  whence  )

static

Moves current absolute buffer position to 'pos' in 'whence' mode. Will move logical position without shifting the buffer, if possible. Will not move beyond the end of file.

Parameters

plugin	plugin context
pos	position to move to
whence	seek mode (SEEK_CUR, SEEK_SET, SEEK_END)

Returns

new absolute position, -1 on error

Definition at line 117 of file extractor_plugin_main.c.

References EXTRACTOR_read_all_(), EXTRACTOR_write_all_(), SeekRequestMessage::file_offset, UpdateMessage::file_size, ProcessingContext::file_size, ProcessingContext::in, LOG, MESSAGE_SEEK, MESSAGE_UPDATED_SHM, SeekRequestMessage::opcode, ProcessingContext::out, ProcessingContext::plugin, ProcessingContext::read_position, SeekRequestMessage::requested_bytes, UpdateMessage::reserved, SeekRequestMessage::reserved, ProcessingContext::shm_map_size, UpdateMessage::shm_off, ProcessingContext::shm_off, UpdateMessage::shm_ready_bytes, ProcessingContext::shm_ready_bytes, EXTRACTOR_PluginList::short_libname, and SeekRequestMessage::whence.

Referenced by handle_start_message(), and plugin_env_read().

plugin_env_send_proc()

static int plugin_env_send_proc ( void *  cls, const char *  plugin_name, enum EXTRACTOR_MetaType  type, enum EXTRACTOR_MetaFormat  format, const char *  data_mime_type, const char *  data, size_t  data_len  )

static

Function called by a plugin in a child process. Transmits the meta data back to the parent process.

Parameters

cls	closure, "struct ProcessingContext" with the FD for transmission
plugin_name	name of the plugin that produced this value; special values can be used (i.e. '<zlib>' for zlib being used in the main libextractor library and yielding meta data).
type	libextractor-type describing the meta data
format	basic format information about data
data_mime_type	mime-type of data (not of the original file); can be NULL (if mime-type is not known)
data	actual meta-data found
data_len	number of bytes in data

Returns

0 to continue extracting, 1 to abort (transmission error)

Definition at line 317 of file extractor_plugin_main.c.

References EXTRACTOR_read_all_(), EXTRACTOR_write_all_(), ProcessingContext::in, LOG, MAX_META_DATA, MESSAGE_CONTINUE_EXTRACTING, MESSAGE_DISCARD_STATE, MESSAGE_META, MetaMessage::meta_format, MetaMessage::meta_type, MetaMessage::mime_length, NULL, MetaMessage::opcode, ProcessingContext::out, MetaMessage::reserved, type, and MetaMessage::value_size.

Referenced by handle_start_message().

process_requests()

static void process_requests ( struct ProcessingContext *  pc )

static

Main loop function for plugins. Reads a message from the plugin input pipe and acts on it.

Parameters

pc	processing context

Definition at line 517 of file extractor_plugin_main.c.

References EXTRACTOR_read_all_(), handle_init_message(), handle_start_message(), ProcessingContext::in, LOG, MESSAGE_DISCARD_STATE, MESSAGE_EXTRACT_START, MESSAGE_INIT_STATE, and MESSAGE_UPDATED_SHM.

Referenced by EXTRACTOR_plugin_main_().