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minix/servers/vfs/main.c
Ben Gras 41e9fedf87 Mostly bugfixes of bugs triggered by the test set. 
bugfixes:
 SYSTEM:
 . removed
        rc->p_priv->s_flags = 0;
   for the priv struct shared by all user processes in get_priv(). this
   should only be done once. doing a SYS_PRIV_USER in sys_privctl()
   caused the flags of all user processes to be reset, so they were no
   longer PREEMPTIBLE. this happened when RS executed a policy script.
   (this broke test1 in the test set)

 VFS/MFS:
 . chown can change the mode of a file, and chmod arguments are only
   part of the full file mode so the full filemode is slightly magic.
   changed these calls so that the final modes are returned to VFS, so
   that the vnode can be kept up-to-date.
   (this broke test11 in the test set)

 MFS:
 . lookup() checked for sizeof(string) instead of sizeof(user_path),
   truncating long path names
   (caught by test 23)
 . truncate functions neglected to update ctime
   (this broke test16)

 VFS:
 . corner case of an empty filename lookup caused fields of a request
   not to be filled in in the lookup functions, not making it clear
   that the lookup had failed, causing messages to garbage processes,
   causing strange failures.
   (caught by test 30)
 . trust v_size in vnode when doing reads or writes on non-special
   files, truncating i/o where necessary; this is necessary for pipes,
   as MFS can't tell when a pipe has been truncated without it being
   told explicitly each time.
   when the last reader/writer on a pipe closes, tell FS about
   the new size using truncate_vn().
   (this broke test 25, among others)
 . permission check for chdir() had disappeared; added a
   forbidden() call
   (caught by test 23)

new code, shouldn't change anything:
 . introduced RTS_SET, RTS_UNSET, and RTS_ISSET macro's, and their
   LOCK variants. These macros set and clear the p_rts_flags field,
   causing a lot of duplicated logic like

       old_flags = rp->p_rts_flags;            /* save value of the flags */
       rp->p_rts_flags &= ~NO_PRIV;
       if (old_flags != 0 && rp->p_rts_flags == 0) lock_enqueue(rp);

   to change into the simpler

       RTS_LOCK_UNSET(rp, NO_PRIV);

   so the macros take care of calling dequeue() and enqueue() (or lock_*()),
   as the case may be). This makes the code a bit more readable and a
   bit less fragile.
 . removed return code from do_clocktick in CLOCK as it currently
   never replies
 . removed some debug code from VFS
 . fixed grant debug message in device.c
 
preemptive checks, tests, changes:
 . added return code checks of receive() to SYSTEM and CLOCK
 . O_TRUNC should never arrive at MFS (added sanity check and removed
   O_TRUNC code)
 . user_path declared with PATH_MAX+1 to let it be null-terminated
 . checks in MFS to see if strings passed by VFS are null-terminated
 
 IS:
 . static irq name table thrown out
2007-02-01 17:50:02 +00:00

512 lines
14 KiB
C
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/* This file contains the main program of the File System. It consists of
* 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();
/* This is the main loop that gets work, processes it, and sends replies. */
while (TRUE) {
get_work(); /* sets who and call_nr */
fp = &fproc[who_p]; /* pointer to proc table struct */
super_user = (fp->fp_effuid == SU_UID ? TRUE : FALSE); /* su? */
if (who_e == PM_PROC_NR && call_nr != PROC_EVENT)
printf("FS: strange, got message %d from PM\n", call_nr);
/* Check for special control messages first. */
if ((call_nr & NOTIFY_MESSAGE)) {
if (call_nr == PROC_EVENT)
{
/* PM tries to get FS to do something */
service_pm();
}
else if (call_nr == SYN_ALARM)
{
/* 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);
}
#if 0
if (!check_vrefs())
{
printf("after call %d from %d/%d\n",
call_nr, who_p, who_e);
panic(__FILE__, "check_vrefs failed at line", __LINE__);
}
#endif
continue;
}
switch(call_nr)
{
case DEVCTL:
error= do_devctl();
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("FS, warning 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
error = (*call_vec[call_nr])();
}
/* Copy the results back to the user and send reply. */
if (error != SUSPEND) { reply(who_e, error); }
}
#if 0
if (!check_vrefs())
{
printf("after call %d from %d/%d\n", call_nr, who_p, who_e);
panic(__FILE__, "check_vrefs failed at line", __LINE__);
}
#endif
}
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.
*/
register struct fproc *rp;
if (reviving != 0) {
/* Revive a suspended process. */
for (rp = &fproc[0]; rp < &fproc[NR_PROCS]; rp++)
if (rp->fp_pid != PID_FREE && rp->fp_revived == REVIVING) {
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));
return;
}
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;
m_out.reply_type = result;
s = send(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. */
register struct inode *rip;
register struct fproc *rfp;
message mess;
int s;
/* 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;
} 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);
/*
if (NR_BUFS < 6) panic(__FILE__,"NR_BUFS < 6", NO_NUM);
if (V1_INODE_SIZE != 32) panic(__FILE__,"V1 inode size != 32", NO_NUM);
if (V2_INODE_SIZE != 64) panic(__FILE__,"V2 inode size != 64", NO_NUM);
if (OPEN_MAX > 8 * sizeof(long))
panic(__FILE__,"Too few bits in fp_cloexec", 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 */
/* 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) {
rfp->fp_rd = get_vnode_x(ROOT_FS_E, ROOT_INODE);
rfp->fp_wd = get_vnode_x(ROOT_FS_E, ROOT_INODE);
} else rfp->fp_endpoint = NONE;
}
}
/*===========================================================================*
* init_root *
*===========================================================================*/
PRIVATE void init_root()
{
struct vmnt *vmp;
struct vnode *root_node;
struct dmap *dp;
message m;
int r = OK;
struct readsuper_req sreq;
struct readsuper_res sres;
/* 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);
}
/* Open the device the file system lives on. */
if ((r = dev_open(root_dev, ROOT_FS_E, (R_BIT|W_BIT))) != OK)
panic(__FILE__,"Cannot open root device", r);
/* Request for reading superblock and root inode */
sreq.fs_e = ROOT_FS_E;
sreq.readonly = 0;
sreq.boottime = boottime;
sreq.driver_e = dp->dmap_driver;
sreq.dev = root_dev;
sreq.slink_storage = user_fullpath;
sreq.isroot = 1;
/* Issue request */
if ((r = req_readsuper(&sreq, &sres)) != OK) {
dev_close(root_dev);
panic(__FILE__,"Cannot read superblock from root", r);
}
/* Fill in root node's fields */
root_node->v_fs_e = sres.fs_e;
root_node->v_inode_nr = sres.inode_nr;
root_node->v_mode = sres.fmode;
root_node->v_size = sres.fsize;
root_node->v_sdev = NO_DEV;
root_node->v_fs_count = 0; /* Is this correct? */
root_node->v_ref_count = 1;
/* Fill in max file size and blocksize for the vmnt */
vmp->m_fs_e = sres.fs_e;
vmp->m_dev = root_dev;
vmp->m_block_size = sres.blocksize;
vmp->m_max_file_size = sres.maxsize;
vmp->m_driver_e = dp->dmap_driver;
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 mounted on itself */
vmp->m_mounted_on = root_node;
root_node->v_ref_count++;
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_STIME:
boottime = m.PM_STIME_TIME;
/* Send new time for all FS processes */
for (vmp = &vmnt[0]; vmp < &vmnt[NR_MNTS]; ++vmp) {
if (vmp->m_fs_e)
req_stime(vmp->m_fs_e, boottime);
}
/* No need to report status to PM */
break;
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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