minix/lib/libsffs/main.c

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/* This file contains the SFFS initialization code and message loop.
*
* The entry points into this file are:
* sffs_init initialization
* sffs_signal signal handler
* sffs_loop main message loop
*
* Created:
* April 2009 (D.C. van Moolenbroek)
*/
#include "inc.h"
/*===========================================================================*
* sffs_init *
*===========================================================================*/
int sffs_init(char *name, const struct sffs_table *table,
struct sffs_params *params)
{
/* Initialize this file server. Called at startup time.
*/
int i;
/* Make sure that the given path prefix doesn't end with a slash. */
i = strlen(params->p_prefix);
while (i > 0 && params->p_prefix[i - 1] == '/') i--;
params->p_prefix[i] = 0;
state.s_mounted = FALSE;
state.s_signaled = FALSE;
sffs_name = name;
sffs_table = table;
sffs_params = params;
return OK;
}
/*===========================================================================*
* sffs_signal *
*===========================================================================*/
void sffs_signal(int signo)
{
/* Only check for termination signal, ignore anything else. */
if (signo != SIGTERM) return;
/* We can now terminate if we have also been unmounted. */
state.s_signaled = TRUE;
if (state.s_mounted) {
dprintf(("%s: got SIGTERM, still mounted\n", sffs_name));
} else {
dprintf(("%s: got SIGTERM, shutting down\n", sffs_name));
/* Break out of the main loop, giving the main program the chance to
* perform further cleanup. This causes sef_receive() to return with
* an EINTR error code.
*/
sef_cancel();
}
}
/*===========================================================================*
* get_work *
*===========================================================================*/
static int get_work(endpoint_t *who_e)
{
/* Receive a request message from VFS. Return TRUE if a new message is ready
* to be processed, or FALSE if sef_stop() was called from the signal handler.
*/
int r;
if ((r = sef_receive(ANY, &m_in)) != OK) {
if (r != EINTR)
panic("receive failed: %d", r);
return FALSE;
}
*who_e = m_in.m_source;
return TRUE;
}
/*===========================================================================*
* send_reply *
*===========================================================================*/
static void send_reply(
int err, /* resulting error code */
int transid
)
{
/* Send a reply message to the requesting party, with the given error code.
*/
int r;
m_out.m_type = err;
if (IS_VFS_FS_TRANSID(transid)) {
/* If a transaction ID was set, reset it */
m_out.m_type = TRNS_ADD_ID(m_out.m_type, transid);
}
if ((r = ipc_send(m_in.m_source, &m_out)) != OK)
printf("%s: ipc_send failed (%d)\n", sffs_name, r);
}
/*===========================================================================*
* sffs_loop *
*===========================================================================*/
void sffs_loop(void)
{
/* The main function of this file server. After initializing, loop, receiving
* one request from VFS at a time, processing it, and sending a reply back to
* VFS. Termination occurs when we both have been unmounted and have received
* a termination signal.
*/
endpoint_t who_e;
int call_nr, err, transid;
while (state.s_mounted || !state.s_signaled) {
if (!get_work(&who_e))
continue; /* Recheck running conditions */
transid = TRNS_GET_ID(m_in.m_type);
m_in.m_type = TRNS_DEL_ID(m_in.m_type);
if (m_in.m_type == 0) {
assert(!IS_VFS_FS_TRANSID(transid));
m_in.m_type = transid; /* Backwards compat. */
transid = 0;
} else
assert(IS_VFS_FS_TRANSID(transid));
call_nr = m_in.m_type;
if (who_e != VFS_PROC_NR) {
continue;
}
if (state.s_mounted || call_nr == REQ_READSUPER) {
call_nr -= FS_BASE;
dprintf(("%s: call %d\n", sffs_name, call_nr));
if (call_nr >= 0 && call_nr < NREQS) {
err = (*call_vec[call_nr])();
} else {
err = ENOSYS;
}
dprintf(("%s: call %d result %d\n", sffs_name, call_nr, err));
}
else err = EINVAL;
send_reply(err, transid);
}
}