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minix/servers/fs/misc.c
Ben Gras 7967177710 endpoint-aware conversion of servers. 
'who', indicating caller number in pm and fs and some other servers, has
been removed in favour of 'who_e' (endpoint) and 'who_p' (proc nr.).

In both PM and FS, isokendpt() convert endpoints to process slot
numbers, returning OK if it was a valid and consistent endpoint number.
okendpt() does the same but panic()s if it doesn't succeed. (In PM,
this is pm_isok..)

pm and fs keep their own records of process endpoints in their proc tables,
which are needed to make kernel calls about those processes.

message field names have changed.

fs drivers are endpoints.

fs now doesn't try to get out of driver deadlock, as the protocol isn't
supposed to let that happen any more. (A warning is printed if ELOCKED
is detected though.)

fproc[].fp_task (indicating which driver the process is suspended on)
became an int.

PM and FS now get endpoint numbers of initial boot processes from the
kernel. These happen to be the same as the old proc numbers, to let
user processes reach them with the old numbers, but FS and PM don't know
that. All new processes after INIT, even after the generation number
wraps around, get endpoint numbers with generation 1 and higher, so
the first instances of the boot processes are the only processes ever
to have endpoint numbers in the old proc number range.

More return code checks of sys_* functions have been added.

IS has become endpoint-aware. Ditched the 'text' and 'data' fields
in the kernel dump (which show locations, not sizes, so aren't terribly
useful) in favour of the endpoint number. Proc number is still visible.

Some other dumps (e.g. dmap, rs) show endpoint numbers now too which got
the formatting changed.

PM reading segments using rw_seg() has changed - it uses other fields
in the message now instead of encoding the segment and process number and
fd in the fd field. For that it uses _read_pm() and _write_pm() which to
_taskcall()s directly in pm/misc.c.

PM now sys_exit()s itself on panic(), instead of sys_abort().

RS also talks in endpoints instead of process numbers.
2006-03-03 10:20:58 +00:00

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/* This file contains a collection of miscellaneous procedures. Some of them
* perform simple system calls. Some others do a little part of system calls
* that are mostly performed by the Memory Manager.
*
* The entry points into this file are
* do_dup: perform the DUP system call
* do_fcntl: perform the FCNTL system call
* do_sync: perform the SYNC system call
* do_fsync: perform the FSYNC system call
* do_reboot: sync disks and prepare for shutdown
* do_fork: adjust the tables after MM has performed a FORK system call
* do_exec: handle files with FD_CLOEXEC on after MM has done an EXEC
* do_exit: a process has exited; note that in the tables
* do_set: set uid or gid for some process
* do_revive: revive a process that was waiting for something (e.g. TTY)
* do_svrctl: file system control
* do_getsysinfo: request copy of FS data structure
*/
#include "fs.h"
#include <fcntl.h>
#include <unistd.h> /* cc runs out of memory with unistd.h :-( */
#include <minix/callnr.h>
#include <minix/endpoint.h>
#include <minix/com.h>
#include <sys/svrctl.h>
#include "buf.h"
#include "file.h"
#include "fproc.h"
#include "inode.h"
#include "param.h"
#include "super.h"
/*===========================================================================*
* do_getsysinfo *
*===========================================================================*/
PUBLIC int do_getsysinfo()
{
struct fproc *proc_addr;
vir_bytes src_addr, dst_addr;
size_t len;
int s;
switch(m_in.info_what) {
case SI_PROC_ADDR:
proc_addr = &fproc[0];
src_addr = (vir_bytes) &proc_addr;
len = sizeof(struct fproc *);
break;
case SI_PROC_TAB:
src_addr = (vir_bytes) fproc;
len = sizeof(struct fproc) * NR_PROCS;
break;
case SI_DMAP_TAB:
src_addr = (vir_bytes) dmap;
len = sizeof(struct dmap) * NR_DEVICES;
break;
default:
return(EINVAL);
}
dst_addr = (vir_bytes) m_in.info_where;
if (OK != (s=sys_datacopy(SELF, src_addr, who_e, dst_addr, len)))
return(s);
return(OK);
}
/*===========================================================================*
* do_dup *
*===========================================================================*/
PUBLIC int do_dup()
{
/* Perform the dup(fd) or dup2(fd,fd2) system call. These system calls are
* obsolete. In fact, it is not even possible to invoke them using the
* current library because the library routines call fcntl(). They are
* provided to permit old binary programs to continue to run.
*/
register int rfd;
register struct filp *f;
struct filp *dummy;
int r;
/* Is the file descriptor valid? */
rfd = m_in.fd & ~DUP_MASK; /* kill off dup2 bit, if on */
if ((f = get_filp(rfd)) == NIL_FILP) return(err_code);
/* Distinguish between dup and dup2. */
if (m_in.fd == rfd) { /* bit not on */
/* dup(fd) */
if ( (r = get_fd(0, 0, &m_in.fd2, &dummy)) != OK) return(r);
} else {
/* dup2(fd, fd2) */
if (m_in.fd2 < 0 || m_in.fd2 >= OPEN_MAX) return(EBADF);
if (rfd == m_in.fd2) return(m_in.fd2); /* ignore the call: dup2(x, x) */
m_in.fd = m_in.fd2; /* prepare to close fd2 */
(void) do_close(); /* cannot fail */
}
/* Success. Set up new file descriptors. */
f->filp_count++;
fp->fp_filp[m_in.fd2] = f;
return(m_in.fd2);
}
/*===========================================================================*
* do_fcntl *
*===========================================================================*/
PUBLIC int do_fcntl()
{
/* Perform the fcntl(fd, request, ...) system call. */
register struct filp *f;
int new_fd, r, fl;
long cloexec_mask; /* bit map for the FD_CLOEXEC flag */
long clo_value; /* FD_CLOEXEC flag in proper position */
struct filp *dummy;
/* Is the file descriptor valid? */
if ((f = get_filp(m_in.fd)) == NIL_FILP) return(err_code);
switch (m_in.request) {
case F_DUPFD:
/* This replaces the old dup() system call. */
if (m_in.addr < 0 || m_in.addr >= OPEN_MAX) return(EINVAL);
if ((r = get_fd(m_in.addr, 0, &new_fd, &dummy)) != OK) return(r);
f->filp_count++;
fp->fp_filp[new_fd] = f;
return(new_fd);
case F_GETFD:
/* Get close-on-exec flag (FD_CLOEXEC in POSIX Table 6-2). */
return( ((fp->fp_cloexec >> m_in.fd) & 01) ? FD_CLOEXEC : 0);
case F_SETFD:
/* Set close-on-exec flag (FD_CLOEXEC in POSIX Table 6-2). */
cloexec_mask = 1L << m_in.fd; /* singleton set position ok */
clo_value = (m_in.addr & FD_CLOEXEC ? cloexec_mask : 0L);
fp->fp_cloexec = (fp->fp_cloexec & ~cloexec_mask) | clo_value;
return(OK);
case F_GETFL:
/* Get file status flags (O_NONBLOCK and O_APPEND). */
fl = f->filp_flags & (O_NONBLOCK | O_APPEND | O_ACCMODE);
return(fl);
case F_SETFL:
/* Set file status flags (O_NONBLOCK and O_APPEND). */
fl = O_NONBLOCK | O_APPEND;
f->filp_flags = (f->filp_flags & ~fl) | (m_in.addr & fl);
return(OK);
case F_GETLK:
case F_SETLK:
case F_SETLKW:
/* Set or clear a file lock. */
r = lock_op(f, m_in.request);
return(r);
case F_FREESP:
{
/* Free a section of a file. Preparation is done here,
* actual freeing in freesp_inode().
*/
off_t start, end;
struct flock flock_arg;
signed long offset;
/* Check if it's a regular file. */
if((f->filp_ino->i_mode & I_TYPE) != I_REGULAR) {
return EINVAL;
}
/* Copy flock data from userspace. */
if((r = sys_datacopy(who_e, (vir_bytes) m_in.name1,
SELF, (vir_bytes) &flock_arg,
(phys_bytes) sizeof(flock_arg))) != OK)
return r;
/* Convert starting offset to signed. */
offset = (signed long) flock_arg.l_start;
/* Figure out starting position base. */
switch(flock_arg.l_whence) {
case SEEK_SET: start = 0; if(offset < 0) return EINVAL; break;
case SEEK_CUR: start = f->filp_pos; break;
case SEEK_END: start = f->filp_ino->i_size; break;
default: return EINVAL;
}
/* Check for overflow or underflow. */
if(offset > 0 && start + offset < start) { return EINVAL; }
if(offset < 0 && start + offset > start) { return EINVAL; }
start += offset;
if(flock_arg.l_len > 0) {
end = start + flock_arg.l_len;
if(end <= start) {
return EINVAL;
}
r = freesp_inode(f->filp_ino, start, end);
} else {
r = truncate_inode(f->filp_ino, start);
}
return r;
}
default:
return(EINVAL);
}
}
/*===========================================================================*
* do_sync *
*===========================================================================*/
PUBLIC int do_sync()
{
/* Perform the sync() system call. Flush all the tables.
* The order in which the various tables are flushed is critical. The
* blocks must be flushed last, since rw_inode() leaves its results in
* the block cache.
*/
register struct inode *rip;
register struct buf *bp;
/* Write all the dirty inodes to the disk. */
for (rip = &inode[0]; rip < &inode[NR_INODES]; rip++)
if (rip->i_count > 0 && rip->i_dirt == DIRTY) rw_inode(rip, WRITING);
/* Write all the dirty blocks to the disk, one drive at a time. */
for (bp = &buf[0]; bp < &buf[NR_BUFS]; bp++)
if (bp->b_dev != NO_DEV && bp->b_dirt == DIRTY) flushall(bp->b_dev);
return(OK); /* sync() can't fail */
}
/*===========================================================================*
* do_fsync *
*===========================================================================*/
PUBLIC int do_fsync()
{
/* Perform the fsync() system call. For now, don't be unnecessarily smart. */
do_sync();
return(OK);
}
/*===========================================================================*
* do_reboot *
*===========================================================================*/
PUBLIC int do_reboot()
{
/* Perform the FS side of the reboot call. */
int i;
struct super_block *sp;
struct inode dummy;
/* Only PM may make this call directly. */
if (who_e != PM_PROC_NR) return(EGENERIC);
/* Do exit processing for all leftover processes and servers. */
for (i = 0; i < NR_PROCS; i++) {
if((m_in.endpt1 = fproc[i].fp_endpoint) != NONE)
do_exit();
}
/* The root file system is mounted onto itself, which keeps it from being
* unmounted. Pull an inode out of thin air and put the root on it.
*/
put_inode(super_block[0].s_imount);
super_block[0].s_imount= &dummy;
dummy.i_count = 2; /* expect one "put" */
/* Unmount all filesystems. File systems are mounted on other file systems,
* so you have to pull off the loose bits repeatedly to get it all undone.
*/
for (i= 0; i < NR_SUPERS; i++) {
/* Unmount at least one. */
for (sp= &super_block[0]; sp < &super_block[NR_SUPERS]; sp++) {
if (sp->s_dev != NO_DEV) (void) unmount(sp->s_dev);
}
}
return(OK);
}
/*===========================================================================*
* do_fork *
*===========================================================================*/
PUBLIC int do_fork()
{
/* Perform those aspects of the fork() system call that relate to files.
* In particular, let the child inherit its parent's file descriptors.
* The parent and child parameters tell who forked off whom. The file
* system uses the same slot numbers as the kernel. Only MM makes this call.
*/
register struct fproc *cp;
int i, parentno, childno;
/* Only PM may make this call directly. */
if (who_e != PM_PROC_NR) return(EGENERIC);
/* Check up-to-dateness of fproc. */
okendpt(m_in.parent_endpt, &parentno);
/* PM gives child endpoint, which implies process slot information.
* Don't call isokendpt, because that will verify if the endpoint
* number is correct in fproc, which it won't be.
*/
childno = _ENDPOINT_P(m_in.child_endpt);
if(childno < 0 || childno >= NR_PROCS)
panic(__FILE__, "FS: bogus child for forking", m_in.child_endpt);
if(fproc[childno].fp_pid != PID_FREE)
panic(__FILE__, "FS: forking on top of in-use child", childno);
/* Copy the parent's fproc struct to the child. */
fproc[childno] = fproc[parentno];
/* Increase the counters in the 'filp' table. */
cp = &fproc[childno];
for (i = 0; i < OPEN_MAX; i++)
if (cp->fp_filp[i] != NIL_FILP) cp->fp_filp[i]->filp_count++;
/* Fill in new process and endpoint id. */
cp->fp_pid = m_in.pid;
cp->fp_endpoint = m_in.child_endpt;
/* A child is not a process leader. */
cp->fp_sesldr = 0;
/* This child has not exec()ced yet. */
cp->fp_execced = 0;
/* Record the fact that both root and working dir have another user. */
dup_inode(cp->fp_rootdir);
dup_inode(cp->fp_workdir);
return(OK);
}
/*===========================================================================*
* do_exec *
*===========================================================================*/
PUBLIC int do_exec()
{
/* Files can be marked with the FD_CLOEXEC bit (in fp->fp_cloexec). When
* MM does an EXEC, it calls FS to allow FS to find these files and close them.
*/
int i, proc;
long bitmap;
/* Only PM may make this call directly. */
if (who_e != PM_PROC_NR) return(EGENERIC);
/* The array of FD_CLOEXEC bits is in the fp_cloexec bit map. */
okendpt(m_in.endpt1, &proc);
fp = &fproc[proc]; /* get_filp() needs 'fp' */
bitmap = fp->fp_cloexec;
if (bitmap) {
/* Check the file desriptors one by one for presence of FD_CLOEXEC. */
for (i = 0; i < OPEN_MAX; i++) {
m_in.fd = i;
if ( (bitmap >> i) & 01) (void) do_close();
}
}
/* This child has now exec()ced. */
fp->fp_execced = 1;
/* Reply to caller (PM) directly. */
reply(who_e, OK);
/* Check if this is a driver that can now be useful. */
dmap_endpt_up(fp->fp_endpoint);
/* Suppress reply to caller (caller already replied to). */
return SUSPEND;
}
/*===========================================================================*
* do_exit *
*===========================================================================*/
PUBLIC int do_exit()
{
/* Perform the file system portion of the exit(status) system call. */
int i, exitee_p, exitee_e, task;
register struct fproc *rfp;
register struct filp *rfilp;
register struct inode *rip;
dev_t dev;
/* Only PM may do the EXIT call directly. */
if (who_e != PM_PROC_NR) return(EGENERIC);
/* Nevertheless, pretend that the call came from the user. */
exitee_e = m_in.endpt1;
okendpt(exitee_e, &exitee_p);
fp = &fproc[exitee_p]; /* get_filp() needs 'fp' */
if (fp->fp_suspended == SUSPENDED) {
task = -fp->fp_task;
if (task == XPIPE || task == XPOPEN) susp_count--;
m_in.ENDPT = exitee_e;
(void) do_unpause(); /* this always succeeds for MM */
fp->fp_suspended = NOT_SUSPENDED;
}
/* Loop on file descriptors, closing any that are open. */
for (i = 0; i < OPEN_MAX; i++) {
m_in.fd = i;
(void) do_close();
}
/* Release root and working directories. */
put_inode(fp->fp_rootdir);
put_inode(fp->fp_workdir);
fp->fp_rootdir = NIL_INODE;
fp->fp_workdir = NIL_INODE;
/* Check if any process is SUSPENDed on this driver.
* If a driver exits, unmap its entries in the dmap table.
* (unmapping has to be done after the first step, because the
* dmap table is used in the first step.)
*/
unsuspend_by_endpt(exitee_e);
dmap_unmap_by_endpt(exitee_e);
/* Invalidate endpoint number for error and sanity checks. */
fp->fp_endpoint = NONE;
/* If a session leader exits then revoke access to its controlling tty from
* all other processes using it.
*/
if (!fp->fp_sesldr) {
fp->fp_pid = PID_FREE;
return(OK); /* not a session leader */
}
fp->fp_sesldr = FALSE;
if (fp->fp_tty == 0) {
fp->fp_pid = PID_FREE;
return(OK); /* no controlling tty */
}
dev = fp->fp_tty;
for (rfp = &fproc[0]; rfp < &fproc[NR_PROCS]; rfp++) {
if (rfp->fp_tty == dev) rfp->fp_tty = 0;
for (i = 0; i < OPEN_MAX; i++) {
if ((rfilp = rfp->fp_filp[i]) == NIL_FILP) continue;
if (rfilp->filp_mode == FILP_CLOSED) continue;
rip = rfilp->filp_ino;
if ((rip->i_mode & I_TYPE) != I_CHAR_SPECIAL) continue;
if ((dev_t) rip->i_zone[0] != dev) continue;
dev_close(dev);
rfilp->filp_mode = FILP_CLOSED;
}
}
/* Mark slot as free. */
fp->fp_pid = PID_FREE;
return(OK);
}
/*===========================================================================*
* do_set *
*===========================================================================*/
PUBLIC int do_set()
{
/* Set uid_t or gid_t field. */
register struct fproc *tfp;
int proc;
/* Only PM may make this call directly. */
if (who_e != PM_PROC_NR) return(EGENERIC);
okendpt(m_in.endpt1, &proc);
tfp = &fproc[proc];
if (call_nr == SETUID) {
tfp->fp_realuid = (uid_t) m_in.real_user_id;
tfp->fp_effuid = (uid_t) m_in.eff_user_id;
}
if (call_nr == SETGID) {
tfp->fp_effgid = (gid_t) m_in.eff_grp_id;
tfp->fp_realgid = (gid_t) m_in.real_grp_id;
}
return(OK);
}
/*===========================================================================*
* do_revive *
*===========================================================================*/
PUBLIC int do_revive()
{
/* A driver, typically TTY, has now gotten the characters that were needed for
* a previous read. The process did not get a reply when it made the call.
* Instead it was suspended. Now we can send the reply to wake it up. This
* business has to be done carefully, since the incoming message is from
* a driver (to which no reply can be sent), and the reply must go to a process
* that blocked earlier. The reply to the caller is inhibited by returning the
* 'SUSPEND' pseudo error, and the reply to the blocked process is done
* explicitly in revive().
*/
revive(m_in.REP_ENDPT, m_in.REP_STATUS);
return(SUSPEND); /* don't reply to the TTY task */
}
/*===========================================================================*
* do_svrctl *
*===========================================================================*/
PUBLIC int do_svrctl()
{
switch (m_in.svrctl_req) {
case FSSIGNON: {
/* A server in user space calls in to manage a device. */
struct fssignon device;
int r, major;
if (fp->fp_effuid != SU_UID && fp->fp_effuid != SERVERS_UID)
return(EPERM);
/* Try to copy request structure to FS. */
if ((r = sys_datacopy(who_e, (vir_bytes) m_in.svrctl_argp,
FS_PROC_NR, (vir_bytes) &device,
(phys_bytes) sizeof(device))) != OK)
return(r);
/* Try to update device mapping. */
major = (device.dev >> MAJOR) & BYTE;
r=map_driver(major, who_e, device.style);
return(r);
}
case FSDEVUNMAP: {
struct fsdevunmap fdu;
int r, major;
/* Try to copy request structure to FS. */
if ((r = sys_datacopy(who_e, (vir_bytes) m_in.svrctl_argp,
FS_PROC_NR, (vir_bytes) &fdu,
(phys_bytes) sizeof(fdu))) != OK)
return(r);
major = (fdu.dev >> MAJOR) & BYTE;
r=map_driver(major, NONE, 0);
return(r);
}
default:
return(EINVAL);
}
}
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