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minix/servers/vfs/main.c
Ben Gras dc1238b7b9 make unpause() decrease susp_count, as it shouldn't be decreased 
if the process was REVIVING. (susp_count doesn't count those
 processes.) this together with dev_io SELECT suspend side effect
 for asynch. character devices solves the hanging pipe bug. or
 at last vastly improves it.

 added sanity checks, turned off by default.

 made the {NOT_,}{SUSPENDING,REVIVING} constants weirder to
 help sanity checking.
2009-05-08 13:56:41 +00:00

601 lines
15 KiB
C
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/*
* a loop that gets messages requesting work, carries out the work, and sends
* replies.
*
* The entry points into this file are:
* main: main program of the Virtual File System
* reply: send a reply to a process after the requested work is done
*
* Changes for VFS:
* Jul 2006 (Balazs Gerofi)
*/
#include "fs.h"
#include <fcntl.h>
#include <string.h>
#include <stdio.h>
#include <signal.h>
#include <assert.h>
#include <stdlib.h>
#include <sys/ioc_memory.h>
#include <sys/svrctl.h>
#include <sys/select.h>
#include <minix/callnr.h>
#include <minix/com.h>
#include <minix/keymap.h>
#include <minix/const.h>
#include <minix/endpoint.h>
#include <minix/safecopies.h>
#include "file.h"
#include "fproc.h"
#include "param.h"
#include <minix/vfsif.h>
#include "vmnt.h"
#include "vnode.h"
#if ENABLE_SYSCALL_STATS
EXTERN unsigned long calls_stats[NCALLS];
#endif
FORWARD _PROTOTYPE( void fs_init, (void) );
FORWARD _PROTOTYPE( void get_work, (void) );
FORWARD _PROTOTYPE( void init_root, (void) );
FORWARD _PROTOTYPE( void service_pm, (void) );
/*===========================================================================*
* main *
*===========================================================================*/
PUBLIC int main()
{
/* This is the main program of the file system. The main loop consists of
* three major activities: getting new work, processing the work, and sending
* the reply. This loop never terminates as long as the file system runs.
*/
int error;
fs_init();
SANITYCHECK;
/* This is the main loop that gets work, processes it, and sends replies. */
while (TRUE) {
SANITYCHECK;
get_work(); /* sets who and call_nr */
if (who_e == PM_PROC_NR && call_nr != PROC_EVENT)
printf("FS: strange, got message %d from PM\n", call_nr);
if (call_nr == DEV_REVIVE)
{
endpoint_t endpt;
endpt = m_in.REP_ENDPT;
if(endpt == FS_PROC_NR) {
endpt = suspended_ep(m_in.m_source, m_in.REP_IO_GRANT);
if(endpt == NONE) {
printf("FS: proc with "
"grant %d from %d not found (revive)\n",
m_in.REP_IO_GRANT, m_in.m_source);
continue;
}
}
revive(endpt, m_in.REP_STATUS);
continue;
}
if (call_nr == DEV_REOPEN_REPL)
{
reopen_reply();
continue;
}
if (call_nr == DEV_CLOSE_REPL)
{
close_reply();
continue;
}
if (call_nr == DEV_SEL_REPL1)
{
select_reply1();
continue;
}
if (call_nr == DEV_SEL_REPL2)
{
select_reply2();
continue;
}
/* Check for special control messages first. */
if ((call_nr & NOTIFY_MESSAGE)) {
if (call_nr == PROC_EVENT && who_e == PM_PROC_NR)
{
/* PM tries to get FS to do something */
service_pm();
}
else if (call_nr == SYN_ALARM && who_e == CLOCK)
{
/* Alarm timer expired. Used only for select().
* Check it.
*/
fs_expire_timers(m_in.NOTIFY_TIMESTAMP);
}
else
{
/* Device notifies us of an event. */
dev_status(&m_in);
}
SANITYCHECK;
continue;
}
/* We only expect notify()s from tasks. */
if(who_p < 0) {
printf("FS: ignoring message from %d (%d)\n",
who_e, m_in.m_type);
continue;
}
/* Now it's safe to set and check fp. */
fp = &fproc[who_p]; /* pointer to proc table struct */
super_user = (fp->fp_effuid == SU_UID ? TRUE : FALSE); /* su? */
#if DO_SANITYCHECKS
if(fp->fp_suspended != NOT_SUSPENDED) {
printf("VFS: requester %d call %d: not not suspended\n",
who_e, call_nr);
panic(__FILE__, "requester suspended", NO_NUM);
}
#endif
/* Calls from VM. */
if(who_e == VM_PROC_NR) {
int caught = 1;
switch(call_nr)
{
case VM_VFS_OPEN:
error = do_vm_open();
break;
case VM_VFS_CLOSE:
error = do_vm_close();
break;
case VM_VFS_MMAP:
error = do_vm_mmap();
break;
default:
caught = 0;
break;
}
if(caught) {
reply(who_e, error);
continue;
}
}
SANITYCHECK;
/* Other calls. */
switch(call_nr)
{
case DEVCTL:
error= do_devctl();
if (error != SUSPEND) reply(who_e, error);
break;
case MAPDRIVER:
error= do_mapdriver();
if (error != SUSPEND) reply(who_e, error);
break;
default:
/* Call the internal function that does the work. */
if (call_nr < 0 || call_nr >= NCALLS) {
error = SUSPEND;
/* Not supposed to happen. */
printf("VFS: illegal %d system call by %d\n",
call_nr, who_e);
} else if (fp->fp_pid == PID_FREE) {
error = ENOSYS;
printf(
"FS, bad process, who = %d, call_nr = %d, endpt1 = %d\n",
who_e, call_nr, m_in.endpt1);
} else {
#if ENABLE_SYSCALL_STATS
calls_stats[call_nr]++;
#endif
SANITYCHECK;
error = (*call_vec[call_nr])();
SANITYCHECK;
}
/* Copy the results back to the user and send reply. */
if (error != SUSPEND) { reply(who_e, error); }
}
SANITYCHECK;
}
return(OK); /* shouldn't come here */
}
/*===========================================================================*
* get_work *
*===========================================================================*/
PRIVATE void get_work()
{
/* Normally wait for new input. However, if 'reviving' is
* nonzero, a suspended process must be awakened.
*/
int r, found_one, fd_nr;
struct filp *f;
register struct fproc *rp;
while (reviving != 0) {
found_one= FALSE;
/* Revive a suspended process. */
for (rp = &fproc[0]; rp < &fproc[NR_PROCS]; rp++)
if (rp->fp_pid != PID_FREE && rp->fp_revived == REVIVING) {
found_one= TRUE;
who_p = (int)(rp - fproc);
who_e = rp->fp_endpoint;
call_nr = rp->fp_fd & BYTE;
m_in.fd = (rp->fp_fd >>8) & BYTE;
m_in.buffer = rp->fp_buffer;
m_in.nbytes = rp->fp_nbytes;
rp->fp_suspended = NOT_SUSPENDED; /*no longer hanging*/
rp->fp_revived = NOT_REVIVING;
reviving--;
/* This should be a pipe I/O, not a device I/O.
* If it is, it'll 'leak' grants.
*/
assert(!GRANT_VALID(rp->fp_grant));
if (rp->fp_task == -XPIPE)
{
fp= rp;
fd_nr= (rp->fp_fd >> 8);
f= get_filp(fd_nr);
assert(f != NULL);
r= rw_pipe((call_nr == READ) ? READING :
WRITING, who_e, fd_nr, f,
rp->fp_buffer, rp->fp_nbytes);
if (r != SUSPEND)
reply(who_e, r);
continue;
}
return;
}
if (!found_one)
panic(__FILE__,"get_work couldn't revive anyone", NO_NUM);
}
for(;;) {
int r;
/* Normal case. No one to revive. */
if ((r=receive(ANY, &m_in)) != OK)
panic(__FILE__,"fs receive error", r);
who_e = m_in.m_source;
who_p = _ENDPOINT_P(who_e);
if(who_p < -NR_TASKS || who_p >= NR_PROCS)
panic(__FILE__,"receive process out of range", who_p);
if(who_p >= 0 && fproc[who_p].fp_endpoint == NONE) {
printf("FS: ignoring request from %d, endpointless slot %d (%d)\n",
m_in.m_source, who_p, m_in.m_type);
continue;
}
if(who_p >= 0 && fproc[who_p].fp_endpoint != who_e) {
printf("FS: receive endpoint inconsistent (%d, %d, %d).\n",
who_e, fproc[who_p].fp_endpoint, who_e);
panic(__FILE__, "FS: inconsistent endpoint ", NO_NUM);
continue;
}
call_nr = m_in.m_type;
return;
}
}
/*===========================================================================*
* reply *
*===========================================================================*/
PUBLIC void reply(whom, result)
int whom; /* process to reply to */
int result; /* result of the call (usually OK or error #) */
{
/* Send a reply to a user process. If the send fails, just ignore it. */
int s;
#if 0
if (call_nr == SYMLINK)
printf("vfs:reply: replying %d for call %d\n", result, call_nr);
#endif
m_out.reply_type = result;
s = sendnb(whom, &m_out);
if (s != OK) printf("VFS: couldn't send reply %d to %d: %d\n",
result, whom, s);
}
/*===========================================================================*
* fs_init *
*===========================================================================*/
PRIVATE void fs_init()
{
/* Initialize global variables, tables, etc. */
int s;
register struct fproc *rfp;
struct vmnt *vmp;
struct vnode *root_vp;
message mess;
/* Clear endpoint field */
last_login_fs_e = NONE;
mount_m_in.m1_p3 = (char *) NONE;
/* Initialize the process table with help of the process manager messages.
* Expect one message for each system process with its slot number and pid.
* When no more processes follow, the magic process number NONE is sent.
* Then, stop and synchronize with the PM.
*/
do {
if (OK != (s=receive(PM_PROC_NR, &mess)))
panic(__FILE__,"FS couldn't receive from PM", s);
if (NONE == mess.PR_ENDPT) break;
rfp = &fproc[mess.PR_SLOT];
rfp->fp_pid = mess.PR_PID;
rfp->fp_endpoint = mess.PR_ENDPT;
rfp->fp_realuid = (uid_t) SYS_UID;
rfp->fp_effuid = (uid_t) SYS_UID;
rfp->fp_realgid = (gid_t) SYS_GID;
rfp->fp_effgid = (gid_t) SYS_GID;
rfp->fp_umask = ~0;
rfp->fp_grant = GRANT_INVALID;
rfp->fp_suspended = NOT_SUSPENDED;
rfp->fp_revived = NOT_REVIVING;
} while (TRUE); /* continue until process NONE */
mess.m_type = OK; /* tell PM that we succeeded */
s = send(PM_PROC_NR, &mess); /* send synchronization message */
/* All process table entries have been set. Continue with FS initialization.
* Certain relations must hold for the file system to work at all. Some
* extra block_size requirements are checked at super-block-read-in time.
*/
if (OPEN_MAX > 127) panic(__FILE__,"OPEN_MAX > 127", NO_NUM);
/* The following initializations are needed to let dev_opcl succeed .*/
fp = (struct fproc *) NULL;
who_e = who_p = FS_PROC_NR;
build_dmap(); /* build device table and map boot driver */
init_root(); /* init root device and load super block */
init_select(); /* init select() structures */
vmp = &vmnt[0]; /* Should be the root filesystem */
if (vmp->m_dev == NO_DEV)
panic(__FILE__, "vfs:fs_init: no root filesystem", NO_NUM);
root_vp= vmp->m_root_node;
/* The root device can now be accessed; set process directories. */
for (rfp=&fproc[0]; rfp < &fproc[NR_PROCS]; rfp++) {
FD_ZERO(&(rfp->fp_filp_inuse));
if (rfp->fp_pid != PID_FREE) {
dup_vnode(root_vp);
rfp->fp_rd = root_vp;
dup_vnode(root_vp);
rfp->fp_wd = root_vp;
} else rfp->fp_endpoint = NONE;
}
system_hz = sys_hz();
}
/*===========================================================================*
* init_root *
*===========================================================================*/
PRIVATE void init_root()
{
int r = OK;
struct vmnt *vmp;
struct vnode *root_node;
struct dmap *dp;
char *label;
message m;
struct node_details resX;
/* Open the root device. */
root_dev = DEV_IMGRD;
ROOT_FS_E = MFS_PROC_NR;
/* Wait FS login message */
if (last_login_fs_e != ROOT_FS_E) {
/* Wait FS login message */
if (receive(ROOT_FS_E, &m) != OK) {
printf("VFS: Error receiving login request from FS_e %d\n",
ROOT_FS_E);
panic(__FILE__, "Error receiving login request from root filesystem\n", ROOT_FS_E);
}
if (m.m_type != FS_READY) {
printf("VFS: Invalid login request from FS_e %d\n",
ROOT_FS_E);
panic(__FILE__, "Error receiving login request from root filesystem\n", ROOT_FS_E);
}
}
last_login_fs_e = NONE;
/* Initialize vmnt table */
for (vmp = &vmnt[0]; vmp < &vmnt[NR_MNTS]; ++vmp)
vmp->m_dev = NO_DEV;
vmp = &vmnt[0];
/* We'll need a vnode for the root inode, check whether there is one */
if ((root_node = get_free_vnode(__FILE__, __LINE__)) == NIL_VNODE) {
panic(__FILE__,"Cannot get free vnode", r);
}
/* Get driver process' endpoint */
dp = &dmap[(root_dev >> MAJOR) & BYTE];
if (dp->dmap_driver == NONE) {
panic(__FILE__,"No driver for root device", r);
}
label= dp->dmap_label;
if (strlen(label) == 0)
{
panic(__FILE__, "vfs:init_root: no label for major", root_dev >> MAJOR);
}
/* Issue request */
r = req_readsuper(ROOT_FS_E, label, root_dev, 0 /*!readonly*/,
1 /*isroot*/, &resX);
if (r != OK) {
panic(__FILE__,"Cannot read superblock from root", r);
}
/* Fill in root node's fields */
root_node->v_fs_e = resX.fs_e;
root_node->v_inode_nr = resX.inode_nr;
root_node->v_mode = resX.fmode;
root_node->v_size = resX.fsize;
root_node->v_sdev = NO_DEV;
root_node->v_fs_count = 1;
root_node->v_ref_count = 1;
/* Fill in max file size and blocksize for the vmnt */
vmp->m_fs_e = resX.fs_e;
vmp->m_dev = root_dev;
vmp->m_flags = 0;
/* Root node is indeed on the partition */
root_node->v_vmnt = vmp;
root_node->v_dev = vmp->m_dev;
/* Root directory is not mounted on a vnode. */
vmp->m_mounted_on = NULL;
vmp->m_root_node = root_node;
}
/*===========================================================================*
* service_pm *
*===========================================================================*/
PRIVATE void service_pm()
{
int r, call;
struct vmnt *vmp;
message m;
/* Ask PM for work until there is nothing left to do */
for (;;)
{
m.m_type= PM_GET_WORK;
r= sendrec(PM_PROC_NR, &m);
if (r != OK)
{
panic("VFS", "service_pm: sendrec failed", r);
}
if (m.m_type == PM_IDLE) {
break;
}
call= m.m_type;
switch(call)
{
case PM_SETSID:
pm_setsid(m.PM_SETSID_PROC);
/* No need to report status to PM */
break;
case PM_SETGID:
pm_setgid(m.PM_SETGID_PROC, m.PM_SETGID_EGID,
m.PM_SETGID_RGID);
/* No need to report status to PM */
break;
case PM_SETUID:
pm_setuid(m.PM_SETUID_PROC, m.PM_SETUID_EGID,
m.PM_SETUID_RGID);
/* No need to report status to PM */
break;
case PM_FORK:
pm_fork(m.PM_FORK_PPROC, m.PM_FORK_CPROC,
m.PM_FORK_CPID);
/* No need to report status to PM */
break;
case PM_EXIT:
case PM_EXIT_TR:
pm_exit(m.PM_EXIT_PROC);
/* Reply dummy status to PM for synchronization */
m.m_type= (call == PM_EXIT_TR ? PM_EXIT_REPLY_TR :
PM_EXIT_REPLY);
/* Keep m.PM_EXIT_PROC */
r= send(PM_PROC_NR, &m);
if (r != OK)
panic(__FILE__, "service_pm: send failed", r);
break;
case PM_UNPAUSE:
case PM_UNPAUSE_TR:
unpause(m.PM_UNPAUSE_PROC);
/* No need to report status to PM */
break;
case PM_REBOOT:
pm_reboot();
/* Reply dummy status to PM for synchronization */
m.m_type= PM_REBOOT_REPLY;
r= send(PM_PROC_NR, &m);
if (r != OK)
panic(__FILE__, "service_pm: send failed", r);
break;
case PM_EXEC:
r= pm_exec(m.PM_EXEC_PROC, m.PM_EXEC_PATH,
m.PM_EXEC_PATH_LEN, m.PM_EXEC_FRAME,
m.PM_EXEC_FRAME_LEN);
/* Reply status to PM */
m.m_type= PM_EXEC_REPLY;
/* Keep m.PM_EXEC_PROC */
m.PM_EXEC_STATUS= r;
r= send(PM_PROC_NR, &m);
if (r != OK)
panic(__FILE__, "service_pm: send failed", r);
break;
case PM_DUMPCORE:
r= pm_dumpcore(m.PM_CORE_PROC,
(struct mem_map *)m.PM_CORE_SEGPTR);
/* Reply status to PM */
m.m_type= PM_CORE_REPLY;
/* Keep m.PM_CORE_PROC */
m.PM_CORE_STATUS= r;
r= send(PM_PROC_NR, &m);
if (r != OK)
panic(__FILE__, "service_pm: send failed", r);
break;
default:
panic("VFS", "service_pm: unknown call", m.m_type);
}
}
}
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