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phunix/servers/vfs/main.c
Thomas Veerman 958b25be50 - Introduce support for sticky bit. 
- Revise VFS-FS protocol and update VFS/MFS/ISOFS accordingly.
- Clean up MFS by removing old, dead code (backwards compatibility is broken by
  the new VFS-FS protocol, anyway) and rewrite other parts. Also, make sure all
  functions have proper banners and prototypes.
- VFS should always provide a (syntactically) valid path to the FS; no need for
  the FS to do sanity checks when leaving/entering mount points.
- Fix several bugs in MFS:
  - Several path lookup bugs in MFS.
  - A link can be too big for the path buffer.
  - A mountpoint can become inaccessible when the creation of a new inode
    fails, because the inode already exists and is a mountpoint.
- Introduce support for supplemental groups.
- Add test 46 to test supplemental group functionality (and removed obsolete
  suppl. tests from test 2).
- Clean up VFS (not everything is done yet).
- ISOFS now opens device read-only. This makes the -r flag in the mount command
  unnecessary (but will still report to be mounted read-write).
- Introduce PipeFS. PipeFS is a new FS that handles all anonymous and
  named pipes. However, named pipes still reside on the (M)FS, as they are part
  of the file system on disk. To make this work VFS now has a concept of
  'mapped' inodes, which causes read, write, truncate and stat requests to be
  redirected to the mapped FS, and all other requests to the original FS.
2009-12-20 20:27:14 +00:00

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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 <minix/debug.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(void)
{
/* 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;
#if DO_SANITYCHECKS
FIXME("VFS: DO_SANITYCHECKS is on");
#endif
/* This is the main loop that gets work, processes it, and sends replies. */
while (TRUE) {
SANITYCHECK;
get_work(); /* sets who and 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 (is_notify(call_nr)) {
if (who_p == PM_PROC_NR)
{
/* Signaled by PM, ignore. */
}
else if (who_p == 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_is_blocked(fp)) {
printf("VFS: requester %d call %d: suspended\n",
who_e, call_nr);
panic(__FILE__, "requester suspended", NO_NUM);
}
#endif
/* Calls from PM. */
if (who_e == PM_PROC_NR) {
service_pm();
continue;
}
/* 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) {
int blocked_on = rp->fp_blocked_on;
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;
/*no longer hanging*/
rp->fp_blocked_on = FP_BLOCKED_ON_NONE;
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 (blocked_on == FP_BLOCKED_ON_PIPE)
{
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);
/*
* negative who_p is never used to access the fproc array. Negative numbers
* (kernel tasks) are treated in a special way
*/
if(who_p >= (int)(sizeof(fproc) / sizeof(struct fproc)))
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) {
if(fproc[who_p].fp_endpoint == NONE) {
printf("slot unknown even\n");
}
printf("FS: receive endpoint inconsistent (source %d, who_p %d, stored ep %d, who_e %d).\n",
m_in.m_source, who_p, fproc[who_p].fp_endpoint, who_e);
#if 0
panic(__FILE__, "FS: inconsistent endpoint ", NO_NUM);
#endif
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_blocked_on = FP_BLOCKED_ON_NONE;
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 res;
/* 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()) == 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*/, &res);
if (r != OK) {
panic(__FILE__,"Cannot read superblock from root", r);
}
/* Fill in root node's fields */
root_node->v_fs_e = res.fs_e;
root_node->v_inode_nr = res.inode_nr;
root_node->v_mode = res.fmode;
root_node->v_size = res.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 = res.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;
switch (call_nr) {
case PM_SETUID:
pm_setuid(m_in.PM_PROC, m_in.PM_EID, m_in.PM_RID);
m_out.m_type = PM_SETUID_REPLY;
m_out.PM_PROC = m_in.PM_PROC;
break;
case PM_SETGID:
pm_setgid(m_in.PM_PROC, m_in.PM_EID, m_in.PM_RID);
m_out.m_type = PM_SETGID_REPLY;
m_out.PM_PROC = m_in.PM_PROC;
break;
case PM_SETSID:
pm_setsid(m_in.PM_PROC);
m_out.m_type = PM_SETSID_REPLY;
m_out.PM_PROC = m_in.PM_PROC;
break;
case PM_EXEC:
r = pm_exec(m_in.PM_PROC, m_in.PM_PATH, m_in.PM_PATH_LEN,
m_in.PM_FRAME, m_in.PM_FRAME_LEN);
/* Reply status to PM */
m_out.m_type = PM_EXEC_REPLY;
m_out.PM_PROC = m_in.PM_PROC;
m_out.PM_STATUS = r;
break;
case PM_EXIT:
pm_exit(m_in.PM_PROC);
/* Reply dummy status to PM for synchronization */
m_out.m_type = PM_EXIT_REPLY;
m_out.PM_PROC = m_in.PM_PROC;
break;
case PM_DUMPCORE:
r = pm_dumpcore(m_in.PM_PROC,
NULL /* (struct mem_map *) m_in.PM_SEGPTR */);
/* Reply status to PM */
m_out.m_type = PM_CORE_REPLY;
m_out.PM_PROC = m_in.PM_PROC;
m_out.PM_STATUS = r;
break;
case PM_FORK:
case PM_FORK_NB:
pm_fork(m_in.PM_PPROC, m_in.PM_PROC, m_in.PM_CPID);
m_out.m_type = (call_nr == PM_FORK) ? PM_FORK_REPLY : PM_FORK_NB_REPLY;
m_out.PM_PROC = m_in.PM_PROC;
break;
case PM_SETGROUPS:
pm_setgroups(m_in.PM_PROC, m_in.PM_GROUP_NO, m_in.PM_GROUP_ADDR);
m_out.m_type = PM_SETGROUPS_REPLY;
m_out.PM_PROC = m_in.PM_PROC;
break;
case PM_UNPAUSE:
unpause(m_in.PM_PROC);
m_out.m_type = PM_UNPAUSE_REPLY;
m_out.PM_PROC = m_in.PM_PROC;
break;
case PM_REBOOT:
pm_reboot();
/* Reply dummy status to PM for synchronization */
m_out.m_type = PM_REBOOT_REPLY;
break;
default:
printf("VFS: don't know how to handle PM request %x\n", call_nr);
return;
}
r = send(PM_PROC_NR, &m_out);
if (r != OK)
panic(__FILE__, "service_pm: send failed", r);
}
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