minix/servers/fs/misc.c
Ben Gras ff67776995 FS:
. loops checked for PID_FREE
  . exit broken down in exit and cleanup functions; when reboot happens,
    cleanup is done but not exit (as processes have not actually exited),
    this keeps drivers working
  . fixed a few uninitialized and unused variables

scripts:
  . new packaging system
2006-03-15 15:34:12 +00:00

590 lines
18 KiB
C

/* 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"
FORWARD _PROTOTYPE( int free_proc, (struct fproc *freed, int flags));
#define FP_EXITING 1
/*===========================================================================*
* 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;
FD_SET(m_in.fd2, &fp->fp_filp_inuse);
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,
* but don't actually exit them (if they were really gone, PM
* will tell us about it).
*/
for (i = 0; i < NR_PROCS; i++)
if((m_in.endpt1 = fproc[i].fp_endpoint) != NONE)
free_proc(&fproc[i], 0);
/* 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);
}
}
/* Sync any unwritten buffers. */
do_sync();
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;
#if 0
printf("do_fork: child %d, slot %d\n", m_in.child_endpt, cp-fproc);
#endif
/* 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;
}
/*===========================================================================*
* free_proc *
*===========================================================================*/
PRIVATE int free_proc(struct fproc *exiter, int flags)
{
int i, task;
register struct fproc *rfp;
register struct filp *rfilp;
register struct inode *rip;
dev_t dev;
fp = exiter; /* get_filp() needs 'fp' */
if (fp->fp_suspended == SUSPENDED) {
task = -fp->fp_task;
if (task == XPIPE || task == XPOPEN) susp_count--;
m_in.ENDPT = fp->fp_endpoint;
(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(fp->fp_endpoint);
/* The rest of these actions is only done when processes actually
* exit.
*/
if(!(flags & FP_EXITING))
return OK;
dmap_unmap_by_endpt(fp->fp_endpoint);
/* Invalidate endpoint number for error and sanity checks. */
fp->fp_endpoint = NONE;
/* If a session leader exits and it has a controlling tty, then revoke
* access to its controlling tty from all other processes using it.
*/
if (fp->fp_sesldr && fp->fp_tty != 0) {
dev = fp->fp_tty;
for (rfp = &fproc[0]; rfp < &fproc[NR_PROCS]; rfp++) {
if(rfp->fp_pid == PID_FREE) continue;
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;
}
}
}
/* Exit done. Mark slot as free. */
fp->fp_pid = PID_FREE;
return(OK);
}
/*===========================================================================*
* do_exit *
*===========================================================================*/
PUBLIC int do_exit()
{
int exitee_p, exitee_e;
/* Perform the file system portion of the exit(status) system call. */
/* 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);
return free_proc(&fproc[exitee_p], FP_EXITING);
}
/*===========================================================================*
* 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, proc_nr_n;
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);
if (isokendpt(who_e, &proc_nr_n) != OK)
return(EINVAL);
/* Try to update device mapping. */
major = (device.dev >> MAJOR) & BYTE;
r=map_driver(major, who_e, device.style);
if (r == OK)
{
/* If a driver has completed its exec(), it can be announced
* to be up.
*/
if(fproc[proc_nr_n].fp_execced) {
dev_up(major);
} else {
dmap[major].dmap_flags |= DMAP_BABY;
}
}
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);
}
}