- Remove redundant code. - Always wait for the initial reply from an asynchronous select request, even if the select has been satisfied on another file descriptor or was canceled due to a serious error. - Restart asynchronous selects if upon reply from the driver turns out that there are deferred operations (and do not forget we're still interested in the results of the deferred operations). - Do not hang a non-blocking select when another blocking select on the same filp is still blocking. - Split blocking operations in read, write, and exceptions (i.e., blocking on read does not imply the write will block as well). - Some loops would iterate over OPEN_MAX file descriptors instead of the "highest" file descriptor. - Use proper internal error return values. - A secondary reply from a synchronous driver is essentially the same as from an asynchronous driver (the only difference being how the answer is received). Merge. - Return proper error code after a driver failure. - Auto-detect whether a driver is synchronous or asynchronous. - Remove some code duplication. - Clean up code (coding style, add missing comments, put all select related code together).
661 lines
19 KiB
C
661 lines
19 KiB
C
/* This file deals with the suspension and revival of processes. A process can
|
|
* be suspended because it wants to read or write from a pipe and can't, or
|
|
* because it wants to read or write from a special file and can't. When a
|
|
* process can't continue it is suspended, and revived later when it is able
|
|
* to continue.
|
|
*
|
|
* The entry points into this file are
|
|
* do_pipe: perform the PIPE system call
|
|
* pipe_check: check to see that a read or write on a pipe is feasible now
|
|
* suspend: suspend a process that cannot do a requested read or write
|
|
* release: check to see if a suspended process can be released and do
|
|
* it
|
|
* revive: mark a suspended process as able to run again
|
|
* unsuspend_by_endpt: revive all processes blocking on a given process
|
|
* do_unpause: a signal has been sent to a process; see if it suspended
|
|
*/
|
|
|
|
#include "fs.h"
|
|
#include <fcntl.h>
|
|
#include <signal.h>
|
|
#include <assert.h>
|
|
#include <minix/callnr.h>
|
|
#include <minix/endpoint.h>
|
|
#include <minix/com.h>
|
|
#include <minix/u64.h>
|
|
#include <sys/select.h>
|
|
#include <sys/time.h>
|
|
#include "file.h"
|
|
#include "fproc.h"
|
|
#include "param.h"
|
|
#include "select.h"
|
|
#include <minix/vfsif.h>
|
|
#include "vnode.h"
|
|
#include "vmnt.h"
|
|
|
|
|
|
/*===========================================================================*
|
|
* do_pipe *
|
|
*===========================================================================*/
|
|
PUBLIC int do_pipe()
|
|
{
|
|
/* Perform the pipe(fil_des) system call. */
|
|
|
|
register struct fproc *rfp;
|
|
int r;
|
|
struct filp *fil_ptr0, *fil_ptr1;
|
|
int fil_des[2]; /* reply goes here */
|
|
struct vnode *vp;
|
|
struct node_details res;
|
|
|
|
/* See if a free vnode is available */
|
|
if ( (vp = get_free_vnode()) == NULL) return(err_code);
|
|
|
|
/* Acquire two file descriptors. */
|
|
rfp = fp;
|
|
if ((r = get_fd(0, R_BIT, &fil_des[0], &fil_ptr0)) != OK) return(r);
|
|
rfp->fp_filp[fil_des[0]] = fil_ptr0;
|
|
FD_SET(fil_des[0], &rfp->fp_filp_inuse);
|
|
fil_ptr0->filp_count = 1;
|
|
if ((r = get_fd(0, W_BIT, &fil_des[1], &fil_ptr1)) != OK) {
|
|
rfp->fp_filp[fil_des[0]] = NULL;
|
|
FD_CLR(fil_des[0], &rfp->fp_filp_inuse);
|
|
fil_ptr0->filp_count = 0;
|
|
return(r);
|
|
}
|
|
rfp->fp_filp[fil_des[1]] = fil_ptr1;
|
|
FD_SET(fil_des[1], &rfp->fp_filp_inuse);
|
|
fil_ptr1->filp_count = 1;
|
|
|
|
/* Create a named pipe inode on PipeFS */
|
|
r = req_newnode(PFS_PROC_NR, fp->fp_effuid, fp->fp_effgid, I_NAMED_PIPE,
|
|
NO_DEV, &res);
|
|
|
|
if (r != OK) {
|
|
rfp->fp_filp[fil_des[0]] = NULL;
|
|
FD_CLR(fil_des[0], &rfp->fp_filp_inuse);
|
|
fil_ptr0->filp_count = 0;
|
|
rfp->fp_filp[fil_des[1]] = NULL;
|
|
FD_CLR(fil_des[1], &rfp->fp_filp_inuse);
|
|
fil_ptr1->filp_count = 0;
|
|
return(r);
|
|
}
|
|
|
|
/* Fill in vnode */
|
|
vp->v_fs_e = res.fs_e;
|
|
vp->v_mapfs_e = res.fs_e;
|
|
vp->v_inode_nr = res.inode_nr;
|
|
vp->v_mapinode_nr = res.inode_nr;
|
|
vp->v_mode = res.fmode;
|
|
vp->v_pipe = I_PIPE;
|
|
vp->v_pipe_rd_pos= 0;
|
|
vp->v_pipe_wr_pos= 0;
|
|
vp->v_fs_count = 1;
|
|
vp->v_mapfs_count = 1;
|
|
vp->v_ref_count = 1;
|
|
vp->v_size = 0;
|
|
vp->v_vmnt = NULL;
|
|
vp->v_dev = NO_DEV;
|
|
|
|
/* Fill in filp objects */
|
|
fil_ptr0->filp_vno = vp;
|
|
dup_vnode(vp);
|
|
fil_ptr1->filp_vno = vp;
|
|
fil_ptr0->filp_flags = O_RDONLY;
|
|
fil_ptr1->filp_flags = O_WRONLY;
|
|
|
|
m_out.reply_i1 = fil_des[0];
|
|
m_out.reply_i2 = fil_des[1];
|
|
|
|
return(OK);
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* map_vnode *
|
|
*===========================================================================*/
|
|
PUBLIC int map_vnode(vp)
|
|
struct vnode *vp;
|
|
{
|
|
int r;
|
|
struct node_details res;
|
|
|
|
if(vp->v_mapfs_e != 0) return(OK); /* Already mapped; nothing to do. */
|
|
|
|
/* Create a temporary mapping of this inode to PipeFS. Read and write
|
|
* operations on data will be handled by PipeFS. The rest by the 'original'
|
|
* FS that holds the inode. */
|
|
if ((r = req_newnode(PFS_PROC_NR, fp->fp_effuid, fp->fp_effgid, I_NAMED_PIPE,
|
|
vp->v_dev, &res)) == OK) {
|
|
vp->v_mapfs_e = res.fs_e;
|
|
vp->v_mapinode_nr = res.inode_nr;
|
|
vp->v_mapfs_count = 1;
|
|
}
|
|
|
|
return(r);
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* pipe_check *
|
|
*===========================================================================*/
|
|
PUBLIC int pipe_check(vp, rw_flag, oflags, bytes, position, notouch)
|
|
register struct vnode *vp; /* the inode of the pipe */
|
|
int rw_flag; /* READING or WRITING */
|
|
int oflags; /* flags set by open or fcntl */
|
|
register int bytes; /* bytes to be read or written (all chunks) */
|
|
u64_t position; /* current file position */
|
|
int notouch; /* check only */
|
|
{
|
|
/* Pipes are a little different. If a process reads from an empty pipe for
|
|
* which a writer still exists, suspend the reader. If the pipe is empty
|
|
* and there is no writer, return 0 bytes. If a process is writing to a
|
|
* pipe and no one is reading from it, give a broken pipe error.
|
|
*/
|
|
off_t pos;
|
|
int r = OK;
|
|
|
|
if (ex64hi(position) != 0)
|
|
panic("pipe_check: position too large in pipe");
|
|
pos = ex64lo(position);
|
|
|
|
/* If reading, check for empty pipe. */
|
|
if (rw_flag == READING) {
|
|
if (pos >= vp->v_size) {
|
|
/* Process is reading from an empty pipe. */
|
|
if (find_filp(vp, W_BIT) != NULL) {
|
|
/* Writer exists */
|
|
if (oflags & O_NONBLOCK)
|
|
r = EAGAIN;
|
|
else
|
|
r = SUSPEND;
|
|
|
|
/* If need be, activate sleeping writers. */
|
|
if (susp_count > 0)
|
|
release(vp, WRITE, susp_count);
|
|
}
|
|
return(r);
|
|
}
|
|
return(bytes);
|
|
}
|
|
|
|
/* Process is writing to a pipe. */
|
|
if (find_filp(vp, R_BIT) == NULL) {
|
|
/* Process is writing, but there is no reader. Tell kernel to generate
|
|
* a SIGPIPE signal. */
|
|
if (!notouch) sys_kill(fp->fp_endpoint, SIGPIPE);
|
|
|
|
return(EPIPE);
|
|
}
|
|
|
|
/* Calculate how many bytes can be written. */
|
|
if (pos + bytes > PIPE_BUF) {
|
|
if (oflags & O_NONBLOCK) {
|
|
if (bytes <= PIPE_BUF) {
|
|
/* Write has to be atomic */
|
|
return(EAGAIN);
|
|
}
|
|
|
|
/* Compute available space */
|
|
bytes = PIPE_BUF - pos;
|
|
|
|
if (bytes > 0) {
|
|
/* Do a partial write. Need to wakeup reader */
|
|
if (!notouch)
|
|
release(vp, READ, susp_count);
|
|
return(bytes);
|
|
} else {
|
|
/* Pipe is full */
|
|
return(EAGAIN);
|
|
}
|
|
}
|
|
|
|
if (bytes > PIPE_BUF) {
|
|
/* Compute available space */
|
|
bytes = PIPE_BUF - pos;
|
|
|
|
if (bytes > 0) {
|
|
/* Do a partial write. Need to wakeup reader
|
|
* since we'll suspend ourself in read_write()
|
|
*/
|
|
if (!notouch)
|
|
release(vp, READ, susp_count);
|
|
return(bytes);
|
|
}
|
|
}
|
|
|
|
/* Pipe is full */
|
|
return(SUSPEND);
|
|
}
|
|
|
|
/* Writing to an empty pipe. Search for suspended reader. */
|
|
if (pos == 0 && !notouch)
|
|
release(vp, READ, susp_count);
|
|
|
|
/* Requested amount fits */
|
|
return(bytes);
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* suspend *
|
|
*===========================================================================*/
|
|
PUBLIC void suspend(int why)
|
|
{
|
|
/* Take measures to suspend the processing of the present system call.
|
|
* Store the parameters to be used upon resuming in the process table.
|
|
* (Actually they are not used when a process is waiting for an I/O device,
|
|
* but they are needed for pipes, and it is not worth making the distinction.)
|
|
* The SUSPEND pseudo error should be returned after calling suspend().
|
|
*/
|
|
|
|
#if DO_SANITYCHECKS
|
|
if (why == FP_BLOCKED_ON_PIPE)
|
|
panic("suspend: called for FP_BLOCKED_ON_PIPE");
|
|
|
|
if(fp_is_blocked(fp))
|
|
panic("suspend: called for suspended process");
|
|
|
|
if(why == FP_BLOCKED_ON_NONE)
|
|
panic("suspend: called for FP_BLOCKED_ON_NONE");
|
|
#endif
|
|
|
|
if (why == FP_BLOCKED_ON_POPEN)
|
|
/* #procs susp'ed on pipe*/
|
|
susp_count++;
|
|
|
|
fp->fp_blocked_on = why;
|
|
assert(fp->fp_grant == GRANT_INVALID || !GRANT_VALID(fp->fp_grant));
|
|
fp->fp_block_fd = m_in.fd;
|
|
fp->fp_block_callnr = call_nr;
|
|
fp->fp_flags &= ~SUSP_REOPEN; /* Clear this flag. The caller
|
|
* can set it when needed.
|
|
*/
|
|
if (why == FP_BLOCKED_ON_LOCK) {
|
|
fp->fp_buffer = (char *) m_in.name1; /* third arg to fcntl() */
|
|
fp->fp_nbytes = m_in.request; /* second arg to fcntl() */
|
|
} else {
|
|
fp->fp_buffer = m_in.buffer; /* for reads and writes */
|
|
fp->fp_nbytes = m_in.nbytes;
|
|
}
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* wait_for *
|
|
*===========================================================================*/
|
|
PUBLIC void wait_for(endpoint_t who)
|
|
{
|
|
if(who == NONE || who == ANY)
|
|
panic("suspend on NONE or ANY");
|
|
suspend(FP_BLOCKED_ON_OTHER);
|
|
fp->fp_task = who;
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* pipe_suspend *
|
|
*===========================================================================*/
|
|
PUBLIC void pipe_suspend(rw_flag, fd_nr, buf, size)
|
|
int rw_flag;
|
|
int fd_nr;
|
|
char *buf;
|
|
size_t size;
|
|
{
|
|
/* Take measures to suspend the processing of the present system call.
|
|
* Store the parameters to be used upon resuming in the process table.
|
|
* (Actually they are not used when a process is waiting for an I/O device,
|
|
* but they are needed for pipes, and it is not worth making the distinction.)
|
|
* The SUSPEND pseudo error should be returned after calling suspend().
|
|
*/
|
|
#if DO_SANITYCHECKS
|
|
if(fp_is_blocked(fp))
|
|
panic("pipe_suspend: called for suspended process");
|
|
#endif
|
|
|
|
susp_count++; /* #procs susp'ed on pipe*/
|
|
fp->fp_blocked_on = FP_BLOCKED_ON_PIPE;
|
|
assert(!GRANT_VALID(fp->fp_grant));
|
|
fp->fp_block_fd = fd_nr;
|
|
fp->fp_block_callnr = ((rw_flag == READING) ? READ : WRITE);
|
|
fp->fp_buffer = buf;
|
|
fp->fp_nbytes = size;
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* unsuspend_by_endpt *
|
|
*===========================================================================*/
|
|
PUBLIC void unsuspend_by_endpt(endpoint_t proc_e)
|
|
{
|
|
/* Revive processes waiting for drivers (SUSPENDed) that have disappeared with
|
|
* return code EAGAIN.
|
|
*/
|
|
struct fproc *rp;
|
|
|
|
for (rp = &fproc[0]; rp < &fproc[NR_PROCS]; rp++) {
|
|
if (rp->fp_pid == PID_FREE) continue;
|
|
if (rp->fp_blocked_on == FP_BLOCKED_ON_OTHER && rp->fp_task == proc_e)
|
|
revive(rp->fp_endpoint, EAGAIN);
|
|
}
|
|
|
|
/* Revive processes waiting in drivers on select()s with EAGAIN too */
|
|
select_unsuspend_by_endpt(proc_e);
|
|
|
|
return;
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* release *
|
|
*===========================================================================*/
|
|
PUBLIC void release(vp, call_nr, count)
|
|
register struct vnode *vp; /* inode of pipe */
|
|
int call_nr; /* READ, WRITE, OPEN or CREAT */
|
|
int count; /* max number of processes to release */
|
|
{
|
|
/* Check to see if any process is hanging on the pipe whose inode is in 'ip'.
|
|
* If one is, and it was trying to perform the call indicated by 'call_nr',
|
|
* release it.
|
|
*/
|
|
|
|
register struct fproc *rp;
|
|
struct filp *f;
|
|
|
|
/* Trying to perform the call also includes SELECTing on it with that
|
|
* operation.
|
|
*/
|
|
if (call_nr == READ || call_nr == WRITE) {
|
|
int op;
|
|
if (call_nr == READ)
|
|
op = SEL_RD;
|
|
else
|
|
op = SEL_WR;
|
|
for(f = &filp[0]; f < &filp[NR_FILPS]; f++) {
|
|
if (f->filp_count < 1 || !(f->filp_pipe_select_ops & op) ||
|
|
f->filp_vno != vp)
|
|
continue;
|
|
select_callback(f, op);
|
|
f->filp_pipe_select_ops &= ~op;
|
|
}
|
|
}
|
|
|
|
/* Search the proc table. */
|
|
for (rp = &fproc[0]; rp < &fproc[NR_PROCS] && count > 0; rp++) {
|
|
if (rp->fp_pid != PID_FREE && fp_is_blocked(rp) &&
|
|
rp->fp_revived == NOT_REVIVING && rp->fp_block_callnr == call_nr &&
|
|
rp->fp_filp[rp->fp_block_fd]->filp_vno == vp) {
|
|
revive(rp->fp_endpoint, 0);
|
|
susp_count--; /* keep track of who is suspended */
|
|
if(susp_count < 0)
|
|
panic("susp_count now negative: %d", susp_count);
|
|
if (--count == 0) return;
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* revive *
|
|
*===========================================================================*/
|
|
PUBLIC void revive(proc_nr_e, returned)
|
|
int proc_nr_e; /* process to revive */
|
|
int returned; /* if hanging on task, how many bytes read */
|
|
{
|
|
/* Revive a previously blocked process. When a process hangs on tty, this
|
|
* is the way it is eventually released.
|
|
*/
|
|
register struct fproc *rfp;
|
|
int blocked_on;
|
|
int fd_nr, proc_nr;
|
|
struct filp *fil_ptr;
|
|
|
|
if(isokendpt(proc_nr_e, &proc_nr) != OK) return;
|
|
|
|
rfp = &fproc[proc_nr];
|
|
if (!fp_is_blocked(rfp) || rfp->fp_revived == REVIVING) return;
|
|
|
|
/* The 'reviving' flag only applies to pipes. Processes waiting for TTY get
|
|
* a message right away. The revival process is different for TTY and pipes.
|
|
* For select and TTY revival, the work is already done, for pipes it is not:
|
|
* the proc must be restarted so it can try again.
|
|
*/
|
|
blocked_on = rfp->fp_blocked_on;
|
|
if (blocked_on == FP_BLOCKED_ON_PIPE || blocked_on == FP_BLOCKED_ON_LOCK) {
|
|
/* Revive a process suspended on a pipe or lock. */
|
|
rfp->fp_revived = REVIVING;
|
|
reviving++; /* process was waiting on pipe or lock */
|
|
} else if (blocked_on == FP_BLOCKED_ON_DOPEN) {
|
|
rfp->fp_blocked_on = FP_BLOCKED_ON_NONE;
|
|
fd_nr = rfp->fp_block_fd;
|
|
if (returned < 0) {
|
|
fil_ptr = rfp->fp_filp[fd_nr];
|
|
rfp->fp_filp[fd_nr] = NULL;
|
|
FD_CLR(fd_nr, &rfp->fp_filp_inuse);
|
|
if (fil_ptr->filp_count != 1) {
|
|
panic("revive: bad count in filp: %d",
|
|
fil_ptr->filp_count);
|
|
}
|
|
fil_ptr->filp_count = 0;
|
|
put_vnode(fil_ptr->filp_vno);
|
|
fil_ptr->filp_vno = NULL;
|
|
reply(proc_nr_e, returned);
|
|
} else
|
|
reply(proc_nr_e, fd_nr);
|
|
} else {
|
|
rfp->fp_blocked_on = FP_BLOCKED_ON_NONE;
|
|
if (blocked_on == FP_BLOCKED_ON_POPEN) {
|
|
/* process blocked in open or create */
|
|
reply(proc_nr_e, rfp->fp_block_fd);
|
|
} else if (blocked_on == FP_BLOCKED_ON_SELECT) {
|
|
reply(proc_nr_e, returned);
|
|
} else {
|
|
/* Revive a process suspended on TTY or other device.
|
|
* Pretend it wants only what there is.
|
|
*/
|
|
rfp->fp_nbytes = returned;
|
|
/* If a grant has been issued by FS for this I/O, revoke
|
|
* it again now that I/O is done.
|
|
*/
|
|
if(GRANT_VALID(rfp->fp_grant)) {
|
|
if(cpf_revoke(rfp->fp_grant)) {
|
|
panic("FS: revoke failed for grant: %d",
|
|
rfp->fp_grant);
|
|
}
|
|
rfp->fp_grant = GRANT_INVALID;
|
|
}
|
|
reply(proc_nr_e, returned); /* unblock the process */
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* unpause *
|
|
*===========================================================================*/
|
|
PUBLIC void unpause(proc_nr_e)
|
|
int proc_nr_e;
|
|
{
|
|
/* A signal has been sent to a user who is paused on the file system.
|
|
* Abort the system call with the EINTR error message.
|
|
*/
|
|
|
|
register struct fproc *rfp;
|
|
int proc_nr_p, blocked_on, fild, status = EINTR;
|
|
struct filp *f;
|
|
dev_t dev;
|
|
message mess;
|
|
int wasreviving = 0;
|
|
|
|
if(isokendpt(proc_nr_e, &proc_nr_p) != OK) {
|
|
printf("VFS: ignoring unpause for bogus endpoint %d\n", proc_nr_e);
|
|
return;
|
|
}
|
|
|
|
rfp = &fproc[proc_nr_p];
|
|
if (!fp_is_blocked(rfp)) return;
|
|
blocked_on = rfp->fp_blocked_on;
|
|
|
|
if (rfp->fp_revived == REVIVING) {
|
|
rfp->fp_revived = NOT_REVIVING;
|
|
reviving--;
|
|
wasreviving = 1;
|
|
}
|
|
|
|
switch (blocked_on) {
|
|
case FP_BLOCKED_ON_PIPE:/* process trying to read or write a pipe */
|
|
break;
|
|
|
|
case FP_BLOCKED_ON_LOCK:/* process trying to set a lock with FCNTL */
|
|
break;
|
|
|
|
case FP_BLOCKED_ON_SELECT:/* process blocking on select() */
|
|
select_forget(proc_nr_e);
|
|
break;
|
|
|
|
case FP_BLOCKED_ON_POPEN: /* process trying to open a fifo */
|
|
break;
|
|
|
|
case FP_BLOCKED_ON_DOPEN:/* process trying to open a device */
|
|
/* Don't cancel OPEN. Just wait until the open completes. */
|
|
return;
|
|
|
|
case FP_BLOCKED_ON_OTHER: /* process trying to do device I/O (e.g. tty)*/
|
|
if (rfp->fp_flags & SUSP_REOPEN) {
|
|
/* Process is suspended while waiting for a reopen.
|
|
* Just reply EINTR.
|
|
*/
|
|
rfp->fp_flags &= ~SUSP_REOPEN;
|
|
status = EINTR;
|
|
break;
|
|
}
|
|
|
|
fild = rfp->fp_block_fd;
|
|
if (fild < 0 || fild >= OPEN_MAX)
|
|
panic("unpause err 2");
|
|
f = rfp->fp_filp[fild];
|
|
dev = (dev_t) f->filp_vno->v_sdev; /* device hung on */
|
|
mess.TTY_LINE = (dev >> MINOR) & BYTE;
|
|
mess.USER_ENDPT = rfp->fp_ioproc;
|
|
mess.IO_GRANT = (char *) rfp->fp_grant;
|
|
|
|
/* Tell kernel R or W. Mode is from current call, not open. */
|
|
mess.COUNT = rfp->fp_block_callnr == READ ? R_BIT : W_BIT;
|
|
mess.m_type = CANCEL;
|
|
fp = rfp; /* hack - ctty_io uses fp */
|
|
(*dmap[(dev >> MAJOR) & BYTE].dmap_io)(rfp->fp_task, &mess);
|
|
status = mess.REP_STATUS;
|
|
if (status == SUSPEND)
|
|
return; /* Process will be revived at a
|
|
* later time.
|
|
*/
|
|
|
|
if(status == EAGAIN) status = EINTR;
|
|
if(GRANT_VALID(rfp->fp_grant)) {
|
|
if(cpf_revoke(rfp->fp_grant)) {
|
|
panic("FS: revoke failed for grant (cancel): %d",
|
|
rfp->fp_grant);
|
|
}
|
|
rfp->fp_grant = GRANT_INVALID;
|
|
}
|
|
break;
|
|
default :
|
|
panic("FS: unknown value: %d", blocked_on);
|
|
}
|
|
|
|
rfp->fp_blocked_on = FP_BLOCKED_ON_NONE;
|
|
|
|
if ((blocked_on == FP_BLOCKED_ON_PIPE ||
|
|
blocked_on == FP_BLOCKED_ON_POPEN) &&
|
|
!wasreviving) {
|
|
susp_count--;
|
|
}
|
|
|
|
reply(proc_nr_e, status); /* signal interrupted call */
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* select_request_pipe *
|
|
*===========================================================================*/
|
|
PUBLIC int select_request_pipe(struct filp *f, int *ops, int block)
|
|
{
|
|
int orig_ops, r = 0, err;
|
|
orig_ops = *ops;
|
|
if ((*ops & (SEL_RD|SEL_ERR))) {
|
|
if ((err = pipe_check(f->filp_vno, READING, 0,
|
|
1, f->filp_pos, 1)) != SUSPEND)
|
|
r |= SEL_RD;
|
|
if (err < 0 && err != SUSPEND)
|
|
r |= SEL_ERR;
|
|
if(err == SUSPEND && f->filp_mode & W_BIT) {
|
|
/* A "meaningless" read select, therefore ready
|
|
for reading and no error set. */
|
|
r |= SEL_RD;
|
|
r &= ~SEL_ERR;
|
|
}
|
|
}
|
|
|
|
if ((*ops & (SEL_WR|SEL_ERR))) {
|
|
if ((err = pipe_check(f->filp_vno, WRITING, 0,
|
|
1, f->filp_pos, 1)) != SUSPEND)
|
|
r |= SEL_WR;
|
|
if (err < 0 && err != SUSPEND)
|
|
r |= SEL_ERR;
|
|
if(err == SUSPEND && f->filp_mode & R_BIT) {
|
|
/* A "meaningless" write select, therefore ready
|
|
for reading and no error set. */
|
|
r |= SEL_WR;
|
|
r &= ~SEL_ERR;
|
|
}
|
|
}
|
|
|
|
/* Some options we collected might not be requested. */
|
|
*ops = r & orig_ops;
|
|
|
|
if (!*ops && block) {
|
|
f->filp_pipe_select_ops |= orig_ops;
|
|
}
|
|
|
|
return(SEL_OK);
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* select_match_pipe *
|
|
*===========================================================================*/
|
|
PUBLIC int select_match_pipe(struct filp *f)
|
|
{
|
|
/* recognize either pipe or named pipe (FIFO) */
|
|
if (f && f->filp_vno && (f->filp_vno->v_mode & I_NAMED_PIPE))
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
#if DO_SANITYCHECKS
|
|
/*===========================================================================*
|
|
* check_pipe *
|
|
*===========================================================================*/
|
|
PUBLIC int check_pipe(void)
|
|
{
|
|
struct fproc *rfp;
|
|
int mycount = 0;
|
|
for (rfp=&fproc[0]; rfp < &fproc[NR_PROCS]; rfp++) {
|
|
if (rfp->fp_pid == PID_FREE)
|
|
continue;
|
|
if(rfp->fp_revived != REVIVING &&
|
|
(rfp->fp_blocked_on == FP_BLOCKED_ON_PIPE ||
|
|
rfp->fp_blocked_on == FP_BLOCKED_ON_POPEN)) {
|
|
mycount++;
|
|
}
|
|
}
|
|
|
|
if(mycount != susp_count) {
|
|
printf("check_pipe: mycount %d susp_count %d\n",
|
|
mycount, susp_count);
|
|
return 0;
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
#endif
|