server_ipc.h File Reference

#include <stdint.h>
#include <atalk/cnid.h>
#include <atalk/globals.h>
#include <atalk/server_child.h>

Go to the source code of this file.

Data Structures
struct	ipc_cache_hint_payload

Macros
#define	IPC_HEADERLEN   14
#define	IPC_MAXMSGSIZE   90
#define	IPC_DISCOLDSESSION   0
#define	IPC_GETSESSION   1
#define	IPC_STATE   2
#define	IPC_VOLUMES   3
#define	IPC_LOGINDONE   4
#define	IPC_CACHE_HINT   5
#define	IPC_SESSIONTOKEN   6
#define	CACHE_HINT_REFRESH   0
#define	CACHE_HINT_DELETE   1
#define	CACHE_HINT_DELETE_CHILDREN   2
#define	HINT_BUF_SIZE   128
#define	HINT_FLUSH_INTERVAL_MS   50

Functions
int	ipc_server_read (server_child_t *children, int fd)
	Read a IPC message from a child.
int	ipc_child_write (AFPObj *obj, uint16_t command, size_t len, void *token)
int	ipc_child_state (AFPObj *obj, uint16_t state)
int	ipc_send_cache_hint (const AFPObj *obj, uint16_t vid, cnid_t cnid, uint8_t event)
	Send a dircache invalidation hint from child to parent.
unsigned long long	ipc_get_hints_sent (void)
unsigned long long	ipc_get_hints_dropped (void)
void	hint_flush_pending (server_child_t *children)
	Flush all buffered hints to sibling children.
int	hint_buf_count (void)
	Return current number of buffered hints.

Macro Definition Documentation

CACHE_HINT_DELETE

#define CACHE_HINT_DELETE   1

direct dir_remove() by CNID

CACHE_HINT_DELETE_CHILDREN

#define CACHE_HINT_DELETE_CHILDREN   2

dircache_remove_children() + remove/refresh parent

CACHE_HINT_REFRESH

#define CACHE_HINT_REFRESH   0

ostat + dir_modify(DCMOD_STAT)

HINT_BUF_SIZE

#define HINT_BUF_SIZE   128

HINT_FLUSH_INTERVAL_MS

#define HINT_FLUSH_INTERVAL_MS   50

IPC_CACHE_HINT

#define IPC_CACHE_HINT   5

Cross-process dircache invalidation hint

IPC_DISCOLDSESSION

#define IPC_DISCOLDSESSION   0

IPC_GETSESSION

#define IPC_GETSESSION   1

IPC_HEADERLEN

#define IPC_HEADERLEN   14

IPC_LOGINDONE

#define IPC_LOGINDONE   4

IPC_MAXMSGSIZE

#define IPC_MAXMSGSIZE   90

IPC_SESSIONTOKEN

#define IPC_SESSIONTOKEN   6

pass opaque reconnect token

IPC_STATE

#define IPC_STATE   2

pass AFP session state

IPC_VOLUMES

#define IPC_VOLUMES   3

pass list of open volumes

Function Documentation

hint_buf_count()

int hint_buf_count ( void )

extern

Return current number of buffered hints.

Used by main event loop to decide poll timeout:

• count > 0: use HINT_FLUSH_INTERVAL_MS timeout
• count == 0: use -1 (infinite, block until event)

hint_flush_pending()

void hint_flush_pending ( server_child_t * children )

extern

Flush all buffered hints to sibling children.

Called from the parent main event loop when:

1. The 50ms poll timeout expires and hint_buf.count > 0
2. hint_buf.count reaches HINT_BUF_SIZE after ipc_server_read

Iterates the child table directly:

• Signals are blocked (no SIGCHLD can modify table)
• SIGCHLD already processed before flush (dead children removed)
• No other thread modifies the table

Performs priority sorting, PIPE_BUF-safe chunked writes.

While this function writes to child pipes, new IPC messages from children accumulate in the kernel socket buffer and are read on the next poll() iteration.

ipc_child_state()

int ipc_child_state ( AFPObj * obj, uint16_t state )

extern

ipc_child_write()

int ipc_child_write ( AFPObj * obj, uint16_t command, size_t len, void * token )

extern

ipc_get_hints_dropped()

unsigned long long ipc_get_hints_dropped ( void )

extern

ipc_get_hints_sent()

unsigned long long ipc_get_hints_sent ( void )

extern

ipc_send_cache_hint()

int ipc_send_cache_hint ( const AFPObj * obj, uint16_t vid, cnid_t cnid, uint8_t event )

extern

Send a dircache invalidation hint from child to parent.

Called directly from AFP command handlers that modify dircache state. Independent of the external FCE system — always active when IPC is available.

Uses a direct non-blocking write() to the IPC socketpair instead of ipc_child_write()/writet() — this ensures the AFP command handler is never blocked waiting for IPC buffer space. If the kernel socket buffer is full (parent not draining fast enough), the hint is silently dropped. Hints are best-effort optimizations, and the dircache validation mechanism & graceful fail-on-use detection makes drops safe.

The 22-byte message (14-byte IPC header + 8-byte payload) is well under the kernel socket buffer size, so partial writes cannot occur when space is available.

Parameters

[in]	obj	AFPObj with ipc_fd
[in]	vid	Volume ID (network byte order, matches vol->v_vid)
[in]	cnid	CNID of affected file/dir (network byte order)
[in]	event	Hint type: CACHE_HINT_REFRESH, CACHE_HINT_DELETE, or CACHE_HINT_DELETE_CHILDREN

Returns

0 on success (or graceful drop), -1 on fatal error

ipc_server_read()

int ipc_server_read ( server_child_t * children, int fd )

extern

Read a IPC message from a child.

This is using an fd with non-blocking IO, so EAGAIN is not an error

Parameters

[in,out]	children	pointer to our structure with all childs
[in]	fd	IPC socket with child

Returns

-1 on error, 0 on success