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minix/drivers/libdriver_asyn/driver.c
David van Moolenbroek b423d7b477 Merge of David's ptrace branch. Summary: 
o Support for ptrace T_ATTACH/T_DETACH and T_SYSCALL
o PM signal handling logic should now work properly, even with debuggers
  being present
o Asynchronous PM/VFS protocol, full IPC support for senda(), and
  AMF_NOREPLY senda() flag

DETAILS

Process stop and delay call handling of PM:
o Added sys_runctl() kernel call with sys_stop() and sys_resume()
  aliases, for PM to stop and resume a process
o Added exception for sending/syscall-traced processes to sys_runctl(),
  and matching SIGKREADY pseudo-signal to PM
o Fixed PM signal logic to deal with requests from a process after
  stopping it (so-called "delay calls"), using the SIGKREADY facility
o Fixed various PM panics due to race conditions with delay calls versus
  VFS calls
o Removed special PRIO_STOP priority value
o Added SYS_LOCK RTS kernel flag, to stop an individual process from
  running while modifying its process structure

Signal and debugger handling in PM:
o Fixed debugger signals being dropped if a second signal arrives when
  the debugger has not retrieved the first one
o Fixed debugger signals being sent to the debugger more than once
o Fixed debugger signals unpausing process in VFS; removed PM_UNPAUSE_TR
  protocol message
o Detached debugger signals from general signal logic and from being
  blocked on VFS calls, meaning that even VFS can now be traced
o Fixed debugger being unable to receive more than one pending signal in
  one process stop
o Fixed signal delivery being delayed needlessly when multiple signals
  are pending
o Fixed wait test for tracer, which was returning for children that were
  not waited for
o Removed second parallel pending call from PM to VFS for any process
o Fixed process becoming runnable between exec() and debugger trap
o Added support for notifying the debugger before the parent when a
  debugged child exits
o Fixed debugger death causing child to remain stopped forever
o Fixed consistently incorrect use of _NSIG

Extensions to ptrace():
o Added T_ATTACH and T_DETACH ptrace request, to attach and detach a
  debugger to and from a process
o Added T_SYSCALL ptrace request, to trace system calls
o Added T_SETOPT ptrace request, to set trace options
o Added TO_TRACEFORK trace option, to attach automatically to children
  of a traced process
o Added TO_ALTEXEC trace option, to send SIGSTOP instead of SIGTRAP upon
  a successful exec() of the tracee
o Extended T_GETUSER ptrace support to allow retrieving a process's priv
  structure
o Removed T_STOP ptrace request again, as it does not help implementing
  debuggers properly
o Added MINIX3-specific ptrace test (test42)
o Added proper manual page for ptrace(2)

Asynchronous PM/VFS interface:
o Fixed asynchronous messages not being checked when receive() is called
  with an endpoint other than ANY
o Added AMF_NOREPLY senda() flag, preventing such messages from
  satisfying the receive part of a sendrec()
o Added asynsend3() that takes optional flags; asynsend() is now a
  #define passing in 0 as third parameter
o Made PM/VFS protocol asynchronous; reintroduced tell_fs()
o Made PM_BASE request/reply number range unique
o Hacked in a horrible temporary workaround into RS to deal with newly
  revealed RS-PM-VFS race condition triangle until VFS is asynchronous

System signal handling:
o Fixed shutdown logic of device drivers; removed old SIGKSTOP signal
o Removed is-superuser check from PM's do_procstat() (aka getsigset())
o Added sigset macros to allow system processes to deal with the full
  signal set, rather than just the POSIX subset

Miscellaneous PM fixes:
o Split do_getset into do_get and do_set, merging common code and making
  structure clearer
o Fixed setpriority() being able to put to sleep processes using an
  invalid parameter, or revive zombie processes
o Made find_proc() global; removed obsolete proc_from_pid()
o Cleanup here and there

Also included:
o Fixed false-positive boot order kernel warning
o Removed last traces of old NOTIFY_FROM code

THINGS OF POSSIBLE INTEREST

o It should now be possible to run PM at any priority, even lower than
  user processes
o No assumptions are made about communication speed between PM and VFS,
  although communication must be FIFO
o A debugger will now receive incoming debuggee signals at kill time
  only; the process may not yet be fully stopped
o A first step has been made towards making the SYSTEM task preemptible
2009-09-30 09:57:22 +00:00

631 lines
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/* This file contains device independent device driver interface.
*
* Changes:
* Sep 25, 2009 removed all macros depending on NOTIFY_FROM() (T. Hruby)
* Jul 25, 2005 added SYS_SIG type for signals (Jorrit N. Herder)
* Sep 15, 2004 added SYN_ALARM type for timeouts (Jorrit N. Herder)
* Jul 23, 2004 removed kernel dependencies (Jorrit N. Herder)
* Apr 02, 1992 constructed from AT wini and floppy driver (Kees J. Bot)
*
*
* The drivers support the following operations (using message format m2):
*
* m_type DEVICE IO_ENDPT COUNT POSITION ADRRESS
* ----------------------------------------------------------------
* | DEV_OPEN | device | proc nr | | | |
* |------------+---------+---------+---------+---------+---------|
* | DEV_CLOSE | device | proc nr | | | |
* |------------+---------+---------+---------+---------+---------|
* | DEV_READ | device | proc nr | bytes | offset | buf ptr |
* |------------+---------+---------+---------+---------+---------|
* | DEV_WRITE | device | proc nr | bytes | offset | buf ptr |
* |------------+---------+---------+---------+---------+---------|
* | DEV_GATHER | device | proc nr | iov len | offset | iov ptr |
* |------------+---------+---------+---------+---------+---------|
* | DEV_SCATTER| device | proc nr | iov len | offset | iov ptr |
* |------------+---------+---------+---------+---------+---------|
* | DEV_IOCTL | device | proc nr |func code| | buf ptr |
* |------------+---------+---------+---------+---------+---------|
* | CANCEL | device | proc nr | r/w | | |
* |------------+---------+---------+---------+---------+---------|
* | HARD_STOP | | | | | |
* |------------+---------+---------+---------+---------+---------|
* | DEV_*_S | variants using safecopies of above |
* ----------------------------------------------------------------
*
* The file contains one entry point:
*
* driver_task: called by the device dependent task entry
*/
#include "../drivers.h"
#include <sys/ioc_disk.h>
#include <minix/mq.h>
#include <minix/endpoint.h>
#include "driver.h"
/* Claim space for variables. */
u8_t *tmp_buf = NULL; /* the DMA buffer eventually */
phys_bytes tmp_phys; /* phys address of DMA buffer */
FORWARD _PROTOTYPE( void init_buffer, (void) );
FORWARD _PROTOTYPE( int do_rdwt, (struct driver *dr, message *mp, int safe) );
FORWARD _PROTOTYPE( int do_vrdwt, (struct driver *dr, message *mp, int safe) );
int device_caller;
PRIVATE mq_t *queue_head = NULL;
/*===========================================================================*
* driver_task *
*===========================================================================*/
PUBLIC void driver_task(dp)
struct driver *dp; /* Device dependent entry points. */
{
/* Main program of any device driver task. */
int r, proc_nr;
message mess, reply_mess;
sigset_t set;
/* Init MQ library. */
mq_init();
/* Here is the main loop of the disk task. It waits for a message, carries
* it out, and sends a reply.
*/
while (TRUE) {
/* Any queued messages? Oldest are at the head. */
if(queue_head) {
mq_t *mq;
mq = queue_head;
memcpy(&mess, &mq->mq_mess, sizeof(mess));
queue_head = queue_head->mq_next;
mq_free(mq);
} else {
int s;
/* Wait for a request to read or write a disk block. */
if ((s=receive(ANY, &mess)) != OK)
panic((*dp->dr_name)(),"receive() failed", s);
}
device_caller = mess.m_source;
proc_nr = mess.IO_ENDPT;
if (mess.m_type == DEV_SELECT)
{
static int first= 1;
if (first)
{
first= 0;
#if 0
printf(
"libdriver_asyn`driver_task: first DEV_SELECT: minor 0x%x, ops 0x%x\n",
mess.DEVICE, mess.IO_ENDPT);
#endif
}
}
/* Now carry out the work. */
if (is_notify(mess.m_type)) {
switch (_ENDPOINT_P(mess.m_source)) {
case HARDWARE:
/* leftover interrupt or expired timer. */
if(dp->dr_hw_int) {
(*dp->dr_hw_int)(dp, &mess);
}
break;
case PM_PROC_NR:
if (getsigset(&set) != 0) break;
(*dp->dr_signal)(dp, &set);
break;
case SYSTEM:
set = mess.NOTIFY_ARG;
(*dp->dr_signal)(dp, &set);
break;
case CLOCK:
(*dp->dr_alarm)(dp, &mess);
break;
case RS_PROC_NR:
notify(mess.m_source);
break;
default:
if(dp->dr_other)
r = (*dp->dr_other)(dp, &mess, 0);
else
r = EINVAL;
goto send_reply;
}
/* done, get a new message */
continue;
}
switch(mess.m_type) {
case DEV_OPEN: r = (*dp->dr_open)(dp, &mess); break;
case DEV_CLOSE: r = (*dp->dr_close)(dp, &mess); break;
#ifdef DEV_IOCTL
case DEV_IOCTL: r = (*dp->dr_ioctl)(dp, &mess, 0); break;
#endif
case DEV_IOCTL_S: r = (*dp->dr_ioctl)(dp, &mess, 1); break;
case CANCEL: r = (*dp->dr_cancel)(dp, &mess);break;
case DEV_SELECT: r = (*dp->dr_select)(dp, &mess);break;
#ifdef DEV_READ
case DEV_READ:
case DEV_WRITE: r = do_rdwt(dp, &mess, 0); break;
#endif
case DEV_READ_S:
case DEV_WRITE_S: r = do_rdwt(dp, &mess, 1); break;
#ifdef DEV_GATHER
case DEV_GATHER:
case DEV_SCATTER: r = do_vrdwt(dp, &mess, 0); break;
#endif
case DEV_GATHER_S:
case DEV_SCATTER_S: r = do_vrdwt(dp, &mess, 1); break;
default:
if(dp->dr_other)
r = (*dp->dr_other)(dp, &mess, 0);
else
r = EINVAL;
break;
}
send_reply:
/* Clean up leftover state. */
(*dp->dr_cleanup)();
/* Finally, prepare and send the reply message. */
if (r != EDONTREPLY) {
if (mess.m_type == DEV_OPEN)
{
reply_mess.m_type = DEV_REVIVE;
reply_mess.REP_ENDPT = proc_nr;
reply_mess.REP_STATUS = r;
}
else if (mess.m_type == DEV_CLOSE)
{
reply_mess.m_type = DEV_CLOSE_REPL;
reply_mess.REP_ENDPT = proc_nr;
reply_mess.REP_STATUS = r;
}
else if (mess.m_type == DEV_READ_S ||
mess.m_type == DEV_WRITE_S)
{
if (r == SUSPEND)
{
printf(
"driver_task: reviving %d with SUSPEND\n",
proc_nr);
}
reply_mess.m_type = DEV_REVIVE;
reply_mess.REP_ENDPT = proc_nr;
reply_mess.REP_IO_GRANT = (cp_grant_id_t)mess.ADDRESS;
reply_mess.REP_STATUS = r;
}
else if (mess.m_type == CANCEL)
{
continue; /* The original request should send a
* reply.
*/
}
else if (mess.m_type == DEV_SELECT)
{
reply_mess.m_type = DEV_SEL_REPL1;
reply_mess.DEV_MINOR = mess.DEVICE;
reply_mess.DEV_SEL_OPS = r;
}
else
{
#if 0
printf("driver_task: TASK_REPLY to req %d\n",
mess.m_type);
#endif
reply_mess.m_type = TASK_REPLY;
reply_mess.REP_ENDPT = proc_nr;
/* Status is # of bytes transferred or error code. */
reply_mess.REP_STATUS = r;
}
r= asynsend(device_caller, &reply_mess);
if (r != OK)
{
printf("driver_task: unable to asynsend to %d: %d\n",
device_caller, r);
}
}
}
}
/*===========================================================================*
* init_buffer *
*===========================================================================*/
PRIVATE void init_buffer()
{
/* Select a buffer that can safely be used for DMA transfers. It may also
* be used to read partition tables and such. Its absolute address is
* 'tmp_phys', the normal address is 'tmp_buf'.
*/
unsigned left;
if(!(tmp_buf = alloc_contig(2*DMA_BUF_SIZE, 0, &tmp_phys))) {
panic(__FILE__, "can't allocate tmp_buf", NO_NUM);
}
}
/*===========================================================================*
* do_rdwt *
*===========================================================================*/
PRIVATE int do_rdwt(dp, mp, safe)
struct driver *dp; /* device dependent entry points */
message *mp; /* pointer to read or write message */
int safe; /* use safecopies? */
{
/* Carry out a single read or write request. */
iovec_t iovec1;
int r, opcode;
phys_bytes phys_addr;
u64_t position;
/* Disk address? Address and length of the user buffer? */
if (mp->COUNT < 0) return(EINVAL);
/* Check the user buffer (not relevant for safe copies). */
if(!safe) {
sys_umap(mp->IO_ENDPT, D, (vir_bytes) mp->ADDRESS, mp->COUNT, &phys_addr);
if (phys_addr == 0) return(EFAULT);
}
/* Prepare for I/O. */
if ((*dp->dr_prepare)(mp->DEVICE) == NIL_DEV) return(ENXIO);
/* Create a one element scatter/gather vector for the buffer. */
if(
#ifdef DEV_READ
mp->m_type == DEV_READ ||
#endif
mp->m_type == DEV_READ_S) opcode = DEV_GATHER_S;
else opcode = DEV_SCATTER_S;
iovec1.iov_addr = (vir_bytes) mp->ADDRESS;
iovec1.iov_size = mp->COUNT;
/* Transfer bytes from/to the device. */
position= make64(mp->POSITION, mp->HIGHPOS);
r = (*dp->dr_transfer)(mp->IO_ENDPT, opcode, position, &iovec1, 1, safe);
/* Return the number of bytes transferred or an error code. */
return(r == OK ? (mp->COUNT - iovec1.iov_size) : r);
}
/*==========================================================================*
* do_vrdwt *
*==========================================================================*/
PRIVATE int do_vrdwt(dp, mp, safe)
struct driver *dp; /* device dependent entry points */
message *mp; /* pointer to read or write message */
int safe; /* use safecopies? */
{
/* Carry out an device read or write to/from a vector of user addresses.
* The "user addresses" are assumed to be safe, i.e. FS transferring to/from
* its own buffers, so they are not checked.
*/
static iovec_t iovec[NR_IOREQS];
iovec_t *iov;
phys_bytes iovec_size;
unsigned nr_req;
int r, j, opcode;
u64_t position;
nr_req = mp->COUNT; /* Length of I/O vector */
{
/* Copy the vector from the caller to kernel space. */
if (nr_req > NR_IOREQS) nr_req = NR_IOREQS;
iovec_size = (phys_bytes) (nr_req * sizeof(iovec[0]));
if(safe) {
if (OK != sys_safecopyfrom(mp->m_source, (vir_bytes) mp->IO_GRANT,
0, (vir_bytes) iovec, iovec_size, D)) {
panic((*dp->dr_name)(),"bad (safe) I/O vector by", mp->m_source);
}
} else {
if (OK != sys_datacopy(mp->m_source, (vir_bytes) mp->ADDRESS,
SELF, (vir_bytes) iovec, iovec_size)) {
panic((*dp->dr_name)(),"bad I/O vector by", mp->m_source);
}
}
iov = iovec;
}
/* Prepare for I/O. */
if ((*dp->dr_prepare)(mp->DEVICE) == NIL_DEV) return(ENXIO);
/* Transfer bytes from/to the device. */
opcode = mp->m_type;
position= make64(mp->POSITION, mp->HIGHPOS);
r = (*dp->dr_transfer)(mp->IO_ENDPT, opcode, position, iov,
nr_req, safe);
/* Copy the I/O vector back to the caller. */
if(safe) {
if (OK != sys_safecopyto(mp->m_source, (vir_bytes) mp->IO_GRANT,
0, (vir_bytes) iovec, iovec_size, D)) {
panic((*dp->dr_name)(),"couldn't return I/O vector", mp->m_source);
}
} else {
sys_datacopy(SELF, (vir_bytes) iovec,
mp->m_source, (vir_bytes) mp->ADDRESS, iovec_size);
}
return(r);
}
/*===========================================================================*
* no_name *
*===========================================================================*/
PUBLIC char *no_name()
{
/* Use this default name if there is no specific name for the device. This was
* originally done by fetching the name from the task table for this process:
* "return(tasktab[proc_number(proc_ptr) + NR_TASKS].name);", but currently a
* real "noname" is returned. Perhaps, some system information service can be
* queried for a name at a later time.
*/
static char name[] = "noname";
return name;
}
/*============================================================================*
* do_nop *
*============================================================================*/
PUBLIC int do_nop(dp, mp)
struct driver *dp;
message *mp;
{
/* Nothing there, or nothing to do. */
switch (mp->m_type) {
case DEV_OPEN: return(ENODEV);
case DEV_CLOSE: return(OK);
case DEV_IOCTL_S:
#ifdef DEV_IOCTL
case DEV_IOCTL: return(ENOTTY);
#endif
default: printf("nop: ignoring code %d\n", mp->m_type); return(EIO);
}
}
/*============================================================================*
* nop_ioctl *
*============================================================================*/
PUBLIC int nop_ioctl(dp, mp, safe)
struct driver *dp;
message *mp;
int safe;
{
return(ENOTTY);
}
/*============================================================================*
* nop_signal *
*============================================================================*/
PUBLIC void nop_signal(dp, set)
struct driver *dp;
sigset_t *set;
{
/* Default action for signal is to ignore. */
}
/*============================================================================*
* nop_alarm *
*============================================================================*/
PUBLIC void nop_alarm(dp, mp)
struct driver *dp;
message *mp;
{
/* Ignore the leftover alarm. */
}
/*===========================================================================*
* nop_prepare *
*===========================================================================*/
PUBLIC struct device *nop_prepare(device)
{
/* Nothing to prepare for. */
return(NIL_DEV);
}
/*===========================================================================*
* nop_cleanup *
*===========================================================================*/
PUBLIC void nop_cleanup()
{
/* Nothing to clean up. */
}
/*===========================================================================*
* nop_cancel *
*===========================================================================*/
PUBLIC int nop_cancel(struct driver *dr, message *m)
{
/* Nothing to do for cancel. */
return(OK);
}
/*===========================================================================*
* nop_select *
*===========================================================================*/
PUBLIC int nop_select(struct driver *dr, message *m)
{
/* Nothing to do for select. */
return(OK);
}
/*============================================================================*
* do_diocntl *
*============================================================================*/
PUBLIC int do_diocntl(dp, mp, safe)
struct driver *dp;
message *mp; /* pointer to ioctl request */
int safe; /* addresses or grants? */
{
/* Carry out a partition setting/getting request. */
struct device *dv;
struct partition entry;
int s;
if (mp->REQUEST != DIOCSETP && mp->REQUEST != DIOCGETP) {
if(dp->dr_other) {
return dp->dr_other(dp, mp, safe);
} else return(ENOTTY);
}
/* Decode the message parameters. */
if ((dv = (*dp->dr_prepare)(mp->DEVICE)) == NIL_DEV) return(ENXIO);
if (mp->REQUEST == DIOCSETP) {
/* Copy just this one partition table entry. */
if(safe) {
s=sys_safecopyfrom(mp->IO_ENDPT, (vir_bytes) mp->IO_GRANT,
0, (vir_bytes) &entry, sizeof(entry), D);
} else{
s=sys_datacopy(mp->IO_ENDPT, (vir_bytes) mp->ADDRESS,
SELF, (vir_bytes) &entry, sizeof(entry));
}
if(s != OK)
return s;
dv->dv_base = entry.base;
dv->dv_size = entry.size;
} else {
/* Return a partition table entry and the geometry of the drive. */
entry.base = dv->dv_base;
entry.size = dv->dv_size;
(*dp->dr_geometry)(&entry);
if(safe) {
s=sys_safecopyto(mp->IO_ENDPT, (vir_bytes) mp->IO_GRANT,
0, (vir_bytes) &entry, sizeof(entry), D);
} else {
s=sys_datacopy(SELF, (vir_bytes) &entry,
mp->IO_ENDPT, (vir_bytes) mp->ADDRESS, sizeof(entry));
}
if (OK != s)
return s;
}
return(OK);
}
/*===========================================================================*
* mq_queue *
*===========================================================================*/
PUBLIC int mq_queue(message *m)
{
mq_t *mq, *mi;
if(!(mq = mq_get()))
panic("libdriver","mq_queue: mq_get failed", NO_NUM);
memcpy(&mq->mq_mess, m, sizeof(mq->mq_mess));
mq->mq_next = NULL;
if(!queue_head) {
queue_head = mq;
} else {
for(mi = queue_head; mi->mq_next; mi = mi->mq_next)
;
mi->mq_next = mq;
}
return OK;
}
#if 0
#define ASYN_NR 100
PRIVATE asynmsg_t msgtable[ASYN_NR];
PRIVATE int first_slot= 0, next_slot= 0;
PUBLIC int asynsend(dst, mp)
endpoint_t dst;
message *mp;
{
int r, src_ind, dst_ind;
unsigned flags;
/* Update first_slot */
for (; first_slot < next_slot; first_slot++)
{
flags= msgtable[first_slot].flags;
if ((flags & (AMF_VALID|AMF_DONE)) == (AMF_VALID|AMF_DONE))
{
if (msgtable[first_slot].result != OK)
{
printf(
"asynsend: found completed entry %d with error %d\n",
first_slot,
msgtable[first_slot].result);
}
continue;
}
if (flags != AMF_EMPTY)
break;
}
if (first_slot >= next_slot)
{
/* Reset first_slot and next_slot */
next_slot= first_slot= 0;
}
if (next_slot >= ASYN_NR)
{
/* Tell the kernel to stop processing */
r= senda(NULL, 0);
if (r != OK)
panic(__FILE__, "asynsend: senda failed", r);
dst_ind= 0;
for (src_ind= first_slot; src_ind<next_slot; src_ind++)
{
flags= msgtable[src_ind].flags;
if ((flags & (AMF_VALID|AMF_DONE)) ==
(AMF_VALID|AMF_DONE))
{
if (msgtable[src_ind].result != OK)
{
printf(
"asynsend: found completed entry %d with error %d\n",
src_ind,
msgtable[src_ind].result);
}
continue;
}
if (flags == AMF_EMPTY)
continue;
#if 0
printf("asynsend: copying entry %d to %d\n",
src_ind, dst_ind);
#endif
if (src_ind != dst_ind)
msgtable[dst_ind]= msgtable[src_ind];
dst_ind++;
}
first_slot= 0;
next_slot= dst_ind;
if (next_slot >= ASYN_NR)
panic(__FILE__, "asynsend: msgtable full", NO_NUM);
}
msgtable[next_slot].dst= dst;
msgtable[next_slot].msg= *mp;
msgtable[next_slot].flags= AMF_VALID; /* Has to be last. The kernel
* scans this table while we
* are sleeping.
*/
next_slot++;
/* Tell the kernel to rescan the table */
return senda(msgtable+first_slot, next_slot-first_slot);
}
#endif
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