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minix/kernel/system/do_trace.c
Ben Gras 41e9fedf87 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
2007-02-01 17:50:02 +00:00

170 lines
5.1 KiB
C
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/* The kernel call implemented in this file:
* m_type: SYS_TRACE
*
* The parameters for this kernel call are:
* m2_i1: CTL_ENDPT process that is traced
* m2_i2: CTL_REQUEST trace request
* m2_l1: CTL_ADDRESS address at traced process' space
* m2_l2: CTL_DATA data to be written or returned here
*/
#include "../system.h"
#include <sys/ptrace.h>
#if USE_TRACE
/*==========================================================================*
* do_trace *
*==========================================================================*/
#define TR_VLSIZE ((vir_bytes) sizeof(long))
PUBLIC int do_trace(m_ptr)
register message *m_ptr;
{
/* Handle the debugging commands supported by the ptrace system call
* The commands are:
* T_STOP stop the process
* T_OK enable tracing by parent for this process
* T_GETINS return value from instruction space
* T_GETDATA return value from data space
* T_GETUSER return value from user process table
* T_SETINS set value from instruction space
* T_SETDATA set value from data space
* T_SETUSER set value in user process table
* T_RESUME resume execution
* T_EXIT exit
* T_STEP set trace bit
*
* The T_OK and T_EXIT commands are handled completely by the process manager,
* all others come here.
*/
register struct proc *rp;
phys_bytes src, dst;
vir_bytes tr_addr = (vir_bytes) m_ptr->CTL_ADDRESS;
long tr_data = m_ptr->CTL_DATA;
int tr_request = m_ptr->CTL_REQUEST;
int tr_proc_nr_e = m_ptr->CTL_ENDPT, tr_proc_nr;
unsigned char ub;
int i;
if(!isokendpt(tr_proc_nr_e, &tr_proc_nr)) return(EINVAL);
if (iskerneln(tr_proc_nr)) return(EPERM);
rp = proc_addr(tr_proc_nr);
if (isemptyp(rp)) return(EIO);
switch (tr_request) {
case T_STOP: /* stop process */
RTS_LOCK_SET(rp, P_STOP);
rp->p_reg.psw &= ~TRACEBIT; /* clear trace bit */
return(OK);
case T_GETINS: /* return value from instruction space */
if (rp->p_memmap[T].mem_len != 0) {
if ((src = umap_local(rp, T, tr_addr, TR_VLSIZE)) == 0) return(EIO);
phys_copy(src, vir2phys(&tr_data), (phys_bytes) sizeof(long));
m_ptr->CTL_DATA = tr_data;
break;
}
/* Text space is actually data space - fall through. */
case T_GETDATA: /* return value from data space */
if ((src = umap_local(rp, D, tr_addr, TR_VLSIZE)) == 0) return(EIO);
phys_copy(src, vir2phys(&tr_data), (phys_bytes) sizeof(long));
m_ptr->CTL_DATA= tr_data;
break;
case T_GETUSER: /* return value from process table */
if ((tr_addr & (sizeof(long) - 1)) != 0 ||
tr_addr > sizeof(struct proc) - sizeof(long))
return(EIO);
m_ptr->CTL_DATA = *(long *) ((char *) rp + (int) tr_addr);
break;
case T_SETINS: /* set value in instruction space */
if (rp->p_memmap[T].mem_len != 0) {
if ((dst = umap_local(rp, T, tr_addr, TR_VLSIZE)) == 0) return(EIO);
phys_copy(vir2phys(&tr_data), dst, (phys_bytes) sizeof(long));
m_ptr->CTL_DATA = 0;
break;
}
/* Text space is actually data space - fall through. */
case T_SETDATA: /* set value in data space */
if ((dst = umap_local(rp, D, tr_addr, TR_VLSIZE)) == 0) return(EIO);
phys_copy(vir2phys(&tr_data), dst, (phys_bytes) sizeof(long));
m_ptr->CTL_DATA = 0;
break;
case T_SETUSER: /* set value in process table */
if ((tr_addr & (sizeof(reg_t) - 1)) != 0 ||
tr_addr > sizeof(struct stackframe_s) - sizeof(reg_t))
return(EIO);
i = (int) tr_addr;
#if (_MINIX_CHIP == _CHIP_INTEL)
/* Altering segment registers might crash the kernel when it
* tries to load them prior to restarting a process, so do
* not allow it.
*/
if (i == (int) &((struct proc *) 0)->p_reg.cs ||
i == (int) &((struct proc *) 0)->p_reg.ds ||
i == (int) &((struct proc *) 0)->p_reg.es ||
#if _WORD_SIZE == 4
i == (int) &((struct proc *) 0)->p_reg.gs ||
i == (int) &((struct proc *) 0)->p_reg.fs ||
#endif
i == (int) &((struct proc *) 0)->p_reg.ss)
return(EIO);
#endif
if (i == (int) &((struct proc *) 0)->p_reg.psw)
/* only selected bits are changeable */
SETPSW(rp, tr_data);
else
*(reg_t *) ((char *) &rp->p_reg + i) = (reg_t) tr_data;
m_ptr->CTL_DATA = 0;
break;
case T_RESUME: /* resume execution */
RTS_LOCK_UNSET(rp, P_STOP);
m_ptr->CTL_DATA = 0;
break;
case T_STEP: /* set trace bit */
rp->p_reg.psw |= TRACEBIT;
RTS_LOCK_UNSET(rp, P_STOP);
m_ptr->CTL_DATA = 0;
break;
case T_READB_INS: /* get value from instruction space */
if (rp->p_memmap[T].mem_len != 0) {
if ((dst = umap_local(rp, T, tr_addr, 1)) == 0) return(EFAULT);
phys_copy(dst, vir2phys(&ub), (phys_bytes) 1);
m_ptr->CTL_DATA = ub;
break;
}
if ((dst = umap_local(rp, D, tr_addr, 1)) == 0) return(EFAULT);
phys_copy(dst, vir2phys(&ub), (phys_bytes) 1);
m_ptr->CTL_DATA = ub;
break;
case T_WRITEB_INS: /* set value in instruction space */
if (rp->p_memmap[T].mem_len != 0) {
if ((dst = umap_local(rp, T, tr_addr, 1)) == 0) return(EFAULT);
phys_copy(vir2phys(&tr_data), dst, (phys_bytes) 1);
m_ptr->CTL_DATA = 0;
break;
}
if ((dst = umap_local(rp, D, tr_addr, 1)) == 0) return(EFAULT);
phys_copy(vir2phys(&tr_data), dst, (phys_bytes) 1);
m_ptr->CTL_DATA = 0;
break;
default:
return(EIO);
}
return(OK);
}
#endif /* USE_TRACE */
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