minix/servers/vfs/filedes.c

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/* This file contains the procedures that manipulate file descriptors.
*
* The entry points into this file are
* get_fd: look for free file descriptor and free filp slots
* get_filp: look up the filp entry for a given file descriptor
* find_filp: find a filp slot that points to a given vnode
* inval_filp: invalidate a filp and associated fd's, only let close()
* happen on it
* do_verify_fd: verify whether the given file descriptor is valid for
* the given endpoint.
* do_set_filp: marks a filp as in-flight.
* do_copy_filp: copies a filp to another endpoint.
* do_put_filp: marks a filp as not in-flight anymore.
* do_cancel_fd: cancel the transaction when something goes wrong for
* the receiver.
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*/
#include <sys/select.h>
#include <minix/callnr.h>
#include <minix/u64.h>
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
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#include <assert.h>
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#include "fs.h"
#include "file.h"
#include "fproc.h"
#include "vnode.h"
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/*===========================================================================*
* get_fd *
*===========================================================================*/
PUBLIC int get_fd(int start, mode_t bits, int *k, struct filp **fpt)
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{
/* Look for a free file descriptor and a free filp slot. Fill in the mode word
* in the latter, but don't claim either one yet, since the open() or creat()
* may yet fail.
*/
register struct filp *f;
register int i;
/* Search the fproc fp_filp table for a free file descriptor. */
for (i = start; i < OPEN_MAX; i++) {
if (fp->fp_filp[i] == NULL && !FD_ISSET(i, &fp->fp_filp_inuse)) {
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/* A file descriptor has been located. */
*k = i;
break;
}
}
/* Check to see if a file descriptor has been found. */
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
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if (i >= OPEN_MAX) return(EMFILE);
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/* Now that a file descriptor has been found, look for a free filp slot. */
for (f = &filp[0]; f < &filp[NR_FILPS]; f++) {
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
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assert(f->filp_count >= 0);
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if (f->filp_count == 0) {
f->filp_mode = bits;
f->filp_pos = cvu64(0);
f->filp_selectors = 0;
f->filp_select_ops = 0;
f->filp_pipe_select_ops = 0;
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f->filp_flags = 0;
f->filp_state = FS_NORMAL;
f->filp_select_flags = 0;
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*fpt = f;
return(OK);
}
}
/* If control passes here, the filp table must be full. Report that back. */
return(ENFILE);
}
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/*===========================================================================*
* get_filp *
*===========================================================================*/
PUBLIC struct filp *get_filp(fild)
int fild; /* file descriptor */
{
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/* See if 'fild' refers to a valid file descr. If so, return its filp ptr. */
return get_filp2(fp, fild);
}
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/*===========================================================================*
* get_filp2 *
*===========================================================================*/
PUBLIC struct filp *get_filp2(rfp, fild)
register struct fproc *rfp;
int fild; /* file descriptor */
{
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/* See if 'fild' refers to a valid file descr. If so, return its filp ptr. */
err_code = EBADF;
if (fild < 0 || fild >= OPEN_MAX ) return(NULL);
if (rfp->fp_filp[fild] == NULL && FD_ISSET(fild, &rfp->fp_filp_inuse))
err_code = EIO; /* The filedes is not there, but is not closed either.
*/
return(rfp->fp_filp[fild]); /* may also be NULL */
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}
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/*===========================================================================*
* find_filp *
*===========================================================================*/
PUBLIC struct filp *find_filp(register struct vnode *vp, mode_t bits)
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{
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
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/* Find a filp slot that refers to the vnode 'vp' in a way as described
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* by the mode bit 'bits'. Used for determining whether somebody is still
* interested in either end of a pipe. Also used when opening a FIFO to
* find partners to share a filp field with (to shared the file position).
* Like 'get_fd' it performs its job by linear search through the filp table.
*/
register struct filp *f;
for (f = &filp[0]; f < &filp[NR_FILPS]; f++) {
if (f->filp_count != 0 && f->filp_vno == vp && (f->filp_mode & bits)){
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return(f);
}
}
/* If control passes here, the filp wasn't there. Report that back. */
return(NULL);
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}
/*===========================================================================*
* invalidate *
*===========================================================================*/
PUBLIC int invalidate(struct filp *fp)
{
/* Invalidate filp. fp_filp_inuse is not cleared, so filp can't be reused
until it is closed first. */
int f, fd, n = 0;
for(f = 0; f < NR_PROCS; f++) {
if(fproc[f].fp_pid == PID_FREE) continue;
for(fd = 0; fd < OPEN_MAX; fd++) {
if(fproc[f].fp_filp[fd] && fproc[f].fp_filp[fd] == fp) {
fproc[f].fp_filp[fd] = NULL;
n++;
}
}
}
return(n); /* Report back how often this filp has been invalidated. */
}
/*===========================================================================*
* verify_fd *
*===========================================================================*/
PUBLIC filp_id_t verify_fd(ep, fd)
endpoint_t ep;
int fd;
{
/*
* verify whether the given file descriptor 'fd' is valid for the
* endpoint 'ep'. When the file descriptor is valid verify_fd returns a
* pointer to that filp, else it returns NULL.
*/
int proc;
if (isokendpt(ep, &proc) != OK) {
return NULL;
}
return get_filp2(&fproc[proc], fd);
}
/*===========================================================================*
* do_verify_fd *
*===========================================================================*/
PUBLIC int do_verify_fd(void)
{
m_out.ADDRESS = (void *) verify_fd(m_in.USER_ENDPT, m_in.COUNT);
return (m_out.ADDRESS != NULL) ? OK : EINVAL;
}
/*===========================================================================*
* set_filp *
*===========================================================================*/
PUBLIC int set_filp(sfilp)
filp_id_t sfilp;
{
if (sfilp == NULL) {
return EINVAL;
} else {
sfilp->filp_count++;
return OK;
}
}
/*===========================================================================*
* do_set_filp *
*===========================================================================*/
PUBLIC int do_set_filp(void)
{
return set_filp((filp_id_t) m_in.ADDRESS);;
}
/*===========================================================================*
* copy_filp *
*===========================================================================*/
PUBLIC int copy_filp(to_ep, cfilp)
endpoint_t to_ep;
filp_id_t cfilp;
{
int j;
int proc;
if (isokendpt(to_ep, &proc) != OK) {
return EINVAL;
}
/* Find an open slot in fp_filp */
for (j = 0; j < OPEN_MAX; j++) {
if (fproc[proc].fp_filp[j] == NULL &&
!FD_ISSET(j, &fproc[proc].fp_filp_inuse)) {
/* Found a free slot, add descriptor */
FD_SET(j, &fproc[proc].fp_filp_inuse);
fproc[proc].fp_filp[j] = cfilp;
fproc[proc].fp_filp[j]->filp_count++;
return j;
}
}
/* File Descriptor Table is Full */
return EMFILE;
}
/*===========================================================================*
* do_copy_filp *
*===========================================================================*/
PUBLIC int do_copy_filp(void)
{
return copy_filp(m_in.USER_ENDPT, (filp_id_t) m_in.ADDRESS);
}
/*===========================================================================*
* put_filp *
*===========================================================================*/
PUBLIC int put_filp(pfilp)
filp_id_t pfilp;
{
if (pfilp == NULL) {
return EINVAL;
} else {
close_filp(pfilp);
return OK;
}
}
/*===========================================================================*
* do_put_filp *
*===========================================================================*/
PUBLIC int do_put_filp(void)
{
return put_filp((filp_id_t) m_in.ADDRESS);
}
/*===========================================================================*
* cancel_fd *
*===========================================================================*/
PUBLIC int cancel_fd(ep, fd)
endpoint_t ep;
int fd;
{
int proc;
if (isokendpt(ep, &proc) != OK) {
return EINVAL;
}
/* Check that the input 'fd' is valid */
if (verify_fd(ep, fd) != NULL) {
/* Found a valid descriptor, remove it */
FD_CLR(fd, &fproc[proc].fp_filp_inuse);
fproc[proc].fp_filp[fd]->filp_count--;
fproc[proc].fp_filp[fd] = NULL;
return fd;
}
/* File descriptor is not valid for the endpoint. */
return EINVAL;
}
/*===========================================================================*
* do_cancel_fd *
*===========================================================================*/
PUBLIC int do_cancel_fd(void)
{
return cancel_fd(m_in.USER_ENDPT, m_in.COUNT);
}
/*===========================================================================*
* close_filp *
*===========================================================================*/
PUBLIC void close_filp(fp)
struct filp *fp;
{
int mode_word, rw;
dev_t dev;
struct vnode *vp;
vp = fp->filp_vno;
if (fp->filp_count - 1 == 0 && fp->filp_mode != FILP_CLOSED) {
/* Check to see if the file is special. */
mode_word = vp->v_mode & I_TYPE;
if (mode_word == I_CHAR_SPECIAL || mode_word == I_BLOCK_SPECIAL) {
dev = (dev_t) vp->v_sdev;
if (mode_word == I_BLOCK_SPECIAL) {
if (vp->v_bfs_e == ROOT_FS_E) {
/* Invalidate the cache unless the special is
* mounted. Assume that the root filesystem's
* is open only for fsck.
*/
req_flush(vp->v_bfs_e, dev);
}
}
/* Do any special processing on device close. */
(void) dev_close(dev, fp-filp);
/* Ignore any errors, even SUSPEND. */
fp->filp_mode = FILP_CLOSED;
}
}
/* If the inode being closed is a pipe, release everyone hanging on it. */
if (vp->v_pipe == I_PIPE) {
rw = (fp->filp_mode & R_BIT ? WRITE : READ);
release(vp, rw, NR_PROCS);
}
/* If a write has been done, the inode is already marked as DIRTY. */
if (--fp->filp_count == 0) {
if (vp->v_pipe == I_PIPE) {
/* Last reader or writer is going. Tell PFS about latest
* pipe size.
*/
truncate_vnode(vp, vp->v_size);
}
put_vnode(fp->filp_vno);
}
}