The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/kern/sys_process.c

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    1 /*-
    2  * Copyright (c) 1994, Sean Eric Fagan
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  * 3. All advertising materials mentioning features or use of this software
   14  *    must display the following acknowledgement:
   15  *      This product includes software developed by Sean Eric Fagan.
   16  * 4. The name of the author may not be used to endorse or promote products
   17  *    derived from this software without specific prior written permission.
   18  *
   19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   29  * SUCH DAMAGE.
   30  */
   31 
   32 #include <sys/cdefs.h>
   33 __FBSDID("$FreeBSD: releng/9.0/sys/kern/sys_process.c 225617 2011-09-16 13:58:51Z kmacy $");
   34 
   35 #include "opt_compat.h"
   36 
   37 #include <sys/param.h>
   38 #include <sys/systm.h>
   39 #include <sys/lock.h>
   40 #include <sys/mutex.h>
   41 #include <sys/syscallsubr.h>
   42 #include <sys/sysent.h>
   43 #include <sys/sysproto.h>
   44 #include <sys/proc.h>
   45 #include <sys/vnode.h>
   46 #include <sys/ptrace.h>
   47 #include <sys/sx.h>
   48 #include <sys/malloc.h>
   49 #include <sys/signalvar.h>
   50 
   51 #include <machine/reg.h>
   52 
   53 #include <security/audit/audit.h>
   54 
   55 #include <vm/vm.h>
   56 #include <vm/pmap.h>
   57 #include <vm/vm_extern.h>
   58 #include <vm/vm_map.h>
   59 #include <vm/vm_kern.h>
   60 #include <vm/vm_object.h>
   61 #include <vm/vm_page.h>
   62 #include <vm/vm_pager.h>
   63 #include <vm/vm_param.h>
   64 
   65 #ifdef COMPAT_FREEBSD32
   66 #include <sys/procfs.h>
   67 #include <compat/freebsd32/freebsd32_signal.h>
   68 
   69 struct ptrace_io_desc32 {
   70         int             piod_op;
   71         uint32_t        piod_offs;
   72         uint32_t        piod_addr;
   73         uint32_t        piod_len;
   74 };
   75 
   76 struct ptrace_vm_entry32 {
   77         int             pve_entry;
   78         int             pve_timestamp;
   79         uint32_t        pve_start;
   80         uint32_t        pve_end;
   81         uint32_t        pve_offset;
   82         u_int           pve_prot;
   83         u_int           pve_pathlen;
   84         int32_t         pve_fileid;
   85         u_int           pve_fsid;
   86         uint32_t        pve_path;
   87 };
   88 
   89 struct ptrace_lwpinfo32 {
   90         lwpid_t pl_lwpid;       /* LWP described. */
   91         int     pl_event;       /* Event that stopped the LWP. */
   92         int     pl_flags;       /* LWP flags. */
   93         sigset_t        pl_sigmask;     /* LWP signal mask */
   94         sigset_t        pl_siglist;     /* LWP pending signal */
   95         struct siginfo32 pl_siginfo;    /* siginfo for signal */
   96         char    pl_tdname[MAXCOMLEN + 1];       /* LWP name. */
   97         int     pl_child_pid;           /* New child pid */
   98 };
   99 
  100 #endif
  101 
  102 /*
  103  * Functions implemented using PROC_ACTION():
  104  *
  105  * proc_read_regs(proc, regs)
  106  *      Get the current user-visible register set from the process
  107  *      and copy it into the regs structure (<machine/reg.h>).
  108  *      The process is stopped at the time read_regs is called.
  109  *
  110  * proc_write_regs(proc, regs)
  111  *      Update the current register set from the passed in regs
  112  *      structure.  Take care to avoid clobbering special CPU
  113  *      registers or privileged bits in the PSL.
  114  *      Depending on the architecture this may have fix-up work to do,
  115  *      especially if the IAR or PCW are modified.
  116  *      The process is stopped at the time write_regs is called.
  117  *
  118  * proc_read_fpregs, proc_write_fpregs
  119  *      deal with the floating point register set, otherwise as above.
  120  *
  121  * proc_read_dbregs, proc_write_dbregs
  122  *      deal with the processor debug register set, otherwise as above.
  123  *
  124  * proc_sstep(proc)
  125  *      Arrange for the process to trap after executing a single instruction.
  126  */
  127 
  128 #define PROC_ACTION(action) do {                                        \
  129         int error;                                                      \
  130                                                                         \
  131         PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);                        \
  132         if ((td->td_proc->p_flag & P_INMEM) == 0)                       \
  133                 error = EIO;                                            \
  134         else                                                            \
  135                 error = (action);                                       \
  136         return (error);                                                 \
  137 } while(0)
  138 
  139 int
  140 proc_read_regs(struct thread *td, struct reg *regs)
  141 {
  142 
  143         PROC_ACTION(fill_regs(td, regs));
  144 }
  145 
  146 int
  147 proc_write_regs(struct thread *td, struct reg *regs)
  148 {
  149 
  150         PROC_ACTION(set_regs(td, regs));
  151 }
  152 
  153 int
  154 proc_read_dbregs(struct thread *td, struct dbreg *dbregs)
  155 {
  156 
  157         PROC_ACTION(fill_dbregs(td, dbregs));
  158 }
  159 
  160 int
  161 proc_write_dbregs(struct thread *td, struct dbreg *dbregs)
  162 {
  163 
  164         PROC_ACTION(set_dbregs(td, dbregs));
  165 }
  166 
  167 /*
  168  * Ptrace doesn't support fpregs at all, and there are no security holes
  169  * or translations for fpregs, so we can just copy them.
  170  */
  171 int
  172 proc_read_fpregs(struct thread *td, struct fpreg *fpregs)
  173 {
  174 
  175         PROC_ACTION(fill_fpregs(td, fpregs));
  176 }
  177 
  178 int
  179 proc_write_fpregs(struct thread *td, struct fpreg *fpregs)
  180 {
  181 
  182         PROC_ACTION(set_fpregs(td, fpregs));
  183 }
  184 
  185 #ifdef COMPAT_FREEBSD32
  186 /* For 32 bit binaries, we need to expose the 32 bit regs layouts. */
  187 int
  188 proc_read_regs32(struct thread *td, struct reg32 *regs32)
  189 {
  190 
  191         PROC_ACTION(fill_regs32(td, regs32));
  192 }
  193 
  194 int
  195 proc_write_regs32(struct thread *td, struct reg32 *regs32)
  196 {
  197 
  198         PROC_ACTION(set_regs32(td, regs32));
  199 }
  200 
  201 int
  202 proc_read_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
  203 {
  204 
  205         PROC_ACTION(fill_dbregs32(td, dbregs32));
  206 }
  207 
  208 int
  209 proc_write_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
  210 {
  211 
  212         PROC_ACTION(set_dbregs32(td, dbregs32));
  213 }
  214 
  215 int
  216 proc_read_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
  217 {
  218 
  219         PROC_ACTION(fill_fpregs32(td, fpregs32));
  220 }
  221 
  222 int
  223 proc_write_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
  224 {
  225 
  226         PROC_ACTION(set_fpregs32(td, fpregs32));
  227 }
  228 #endif
  229 
  230 int
  231 proc_sstep(struct thread *td)
  232 {
  233 
  234         PROC_ACTION(ptrace_single_step(td));
  235 }
  236 
  237 int
  238 proc_rwmem(struct proc *p, struct uio *uio)
  239 {
  240         vm_map_t map;
  241         vm_offset_t pageno;             /* page number */
  242         vm_prot_t reqprot;
  243         int error, fault_flags, page_offset, writing;
  244 
  245         /*
  246          * Assert that someone has locked this vmspace.  (Should be
  247          * curthread but we can't assert that.)  This keeps the process
  248          * from exiting out from under us until this operation completes.
  249          */
  250         KASSERT(p->p_lock >= 1, ("%s: process %p (pid %d) not held", __func__,
  251             p, p->p_pid));
  252 
  253         /*
  254          * The map we want...
  255          */
  256         map = &p->p_vmspace->vm_map;
  257 
  258         /*
  259          * If we are writing, then we request vm_fault() to create a private
  260          * copy of each page.  Since these copies will not be writeable by the
  261          * process, we must explicity request that they be dirtied.
  262          */
  263         writing = uio->uio_rw == UIO_WRITE;
  264         reqprot = writing ? VM_PROT_COPY | VM_PROT_READ : VM_PROT_READ;
  265         fault_flags = writing ? VM_FAULT_DIRTY : VM_FAULT_NORMAL;
  266 
  267         /*
  268          * Only map in one page at a time.  We don't have to, but it
  269          * makes things easier.  This way is trivial - right?
  270          */
  271         do {
  272                 vm_offset_t uva;
  273                 u_int len;
  274                 vm_page_t m;
  275 
  276                 uva = (vm_offset_t)uio->uio_offset;
  277 
  278                 /*
  279                  * Get the page number of this segment.
  280                  */
  281                 pageno = trunc_page(uva);
  282                 page_offset = uva - pageno;
  283 
  284                 /*
  285                  * How many bytes to copy
  286                  */
  287                 len = min(PAGE_SIZE - page_offset, uio->uio_resid);
  288 
  289                 /*
  290                  * Fault and hold the page on behalf of the process.
  291                  */
  292                 error = vm_fault_hold(map, pageno, reqprot, fault_flags, &m);
  293                 if (error != KERN_SUCCESS) {
  294                         if (error == KERN_RESOURCE_SHORTAGE)
  295                                 error = ENOMEM;
  296                         else
  297                                 error = EFAULT;
  298                         break;
  299                 }
  300 
  301                 /*
  302                  * Now do the i/o move.
  303                  */
  304                 error = uiomove_fromphys(&m, page_offset, len, uio);
  305 
  306                 /* Make the I-cache coherent for breakpoints. */
  307                 if (writing && error == 0) {
  308                         vm_map_lock_read(map);
  309                         if (vm_map_check_protection(map, pageno, pageno +
  310                             PAGE_SIZE, VM_PROT_EXECUTE))
  311                                 vm_sync_icache(map, uva, len);
  312                         vm_map_unlock_read(map);
  313                 }
  314 
  315                 /*
  316                  * Release the page.
  317                  */
  318                 vm_page_lock(m);
  319                 vm_page_unhold(m);
  320                 vm_page_unlock(m);
  321 
  322         } while (error == 0 && uio->uio_resid > 0);
  323 
  324         return (error);
  325 }
  326 
  327 static int
  328 ptrace_vm_entry(struct thread *td, struct proc *p, struct ptrace_vm_entry *pve)
  329 {
  330         struct vattr vattr;
  331         vm_map_t map;
  332         vm_map_entry_t entry;
  333         vm_object_t obj, tobj, lobj;
  334         struct vmspace *vm;
  335         struct vnode *vp;
  336         char *freepath, *fullpath;
  337         u_int pathlen;
  338         int error, index, vfslocked;
  339 
  340         error = 0;
  341         obj = NULL;
  342 
  343         vm = vmspace_acquire_ref(p);
  344         map = &vm->vm_map;
  345         vm_map_lock_read(map);
  346 
  347         do {
  348                 entry = map->header.next;
  349                 index = 0;
  350                 while (index < pve->pve_entry && entry != &map->header) {
  351                         entry = entry->next;
  352                         index++;
  353                 }
  354                 if (index != pve->pve_entry) {
  355                         error = EINVAL;
  356                         break;
  357                 }
  358                 while (entry != &map->header &&
  359                     (entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0) {
  360                         entry = entry->next;
  361                         index++;
  362                 }
  363                 if (entry == &map->header) {
  364                         error = ENOENT;
  365                         break;
  366                 }
  367 
  368                 /* We got an entry. */
  369                 pve->pve_entry = index + 1;
  370                 pve->pve_timestamp = map->timestamp;
  371                 pve->pve_start = entry->start;
  372                 pve->pve_end = entry->end - 1;
  373                 pve->pve_offset = entry->offset;
  374                 pve->pve_prot = entry->protection;
  375 
  376                 /* Backing object's path needed? */
  377                 if (pve->pve_pathlen == 0)
  378                         break;
  379 
  380                 pathlen = pve->pve_pathlen;
  381                 pve->pve_pathlen = 0;
  382 
  383                 obj = entry->object.vm_object;
  384                 if (obj != NULL)
  385                         VM_OBJECT_LOCK(obj);
  386         } while (0);
  387 
  388         vm_map_unlock_read(map);
  389         vmspace_free(vm);
  390 
  391         pve->pve_fsid = VNOVAL;
  392         pve->pve_fileid = VNOVAL;
  393 
  394         if (error == 0 && obj != NULL) {
  395                 lobj = obj;
  396                 for (tobj = obj; tobj != NULL; tobj = tobj->backing_object) {
  397                         if (tobj != obj)
  398                                 VM_OBJECT_LOCK(tobj);
  399                         if (lobj != obj)
  400                                 VM_OBJECT_UNLOCK(lobj);
  401                         lobj = tobj;
  402                         pve->pve_offset += tobj->backing_object_offset;
  403                 }
  404                 vp = (lobj->type == OBJT_VNODE) ? lobj->handle : NULL;
  405                 if (vp != NULL)
  406                         vref(vp);
  407                 if (lobj != obj)
  408                         VM_OBJECT_UNLOCK(lobj);
  409                 VM_OBJECT_UNLOCK(obj);
  410 
  411                 if (vp != NULL) {
  412                         freepath = NULL;
  413                         fullpath = NULL;
  414                         vn_fullpath(td, vp, &fullpath, &freepath);
  415                         vfslocked = VFS_LOCK_GIANT(vp->v_mount);
  416                         vn_lock(vp, LK_SHARED | LK_RETRY);
  417                         if (VOP_GETATTR(vp, &vattr, td->td_ucred) == 0) {
  418                                 pve->pve_fileid = vattr.va_fileid;
  419                                 pve->pve_fsid = vattr.va_fsid;
  420                         }
  421                         vput(vp);
  422                         VFS_UNLOCK_GIANT(vfslocked);
  423 
  424                         if (fullpath != NULL) {
  425                                 pve->pve_pathlen = strlen(fullpath) + 1;
  426                                 if (pve->pve_pathlen <= pathlen) {
  427                                         error = copyout(fullpath, pve->pve_path,
  428                                             pve->pve_pathlen);
  429                                 } else
  430                                         error = ENAMETOOLONG;
  431                         }
  432                         if (freepath != NULL)
  433                                 free(freepath, M_TEMP);
  434                 }
  435         }
  436 
  437         return (error);
  438 }
  439 
  440 #ifdef COMPAT_FREEBSD32
  441 static int      
  442 ptrace_vm_entry32(struct thread *td, struct proc *p,
  443     struct ptrace_vm_entry32 *pve32)
  444 {
  445         struct ptrace_vm_entry pve;
  446         int error;
  447 
  448         pve.pve_entry = pve32->pve_entry;
  449         pve.pve_pathlen = pve32->pve_pathlen;
  450         pve.pve_path = (void *)(uintptr_t)pve32->pve_path;
  451 
  452         error = ptrace_vm_entry(td, p, &pve);
  453         if (error == 0) {
  454                 pve32->pve_entry = pve.pve_entry;
  455                 pve32->pve_timestamp = pve.pve_timestamp;
  456                 pve32->pve_start = pve.pve_start;
  457                 pve32->pve_end = pve.pve_end;
  458                 pve32->pve_offset = pve.pve_offset;
  459                 pve32->pve_prot = pve.pve_prot;
  460                 pve32->pve_fileid = pve.pve_fileid;
  461                 pve32->pve_fsid = pve.pve_fsid;
  462         }
  463 
  464         pve32->pve_pathlen = pve.pve_pathlen;
  465         return (error);
  466 }
  467 
  468 static void
  469 ptrace_lwpinfo_to32(const struct ptrace_lwpinfo *pl,
  470     struct ptrace_lwpinfo32 *pl32)
  471 {
  472 
  473         pl32->pl_lwpid = pl->pl_lwpid;
  474         pl32->pl_event = pl->pl_event;
  475         pl32->pl_flags = pl->pl_flags;
  476         pl32->pl_sigmask = pl->pl_sigmask;
  477         pl32->pl_siglist = pl->pl_siglist;
  478         siginfo_to_siginfo32(&pl->pl_siginfo, &pl32->pl_siginfo);
  479         strcpy(pl32->pl_tdname, pl->pl_tdname);
  480         pl32->pl_child_pid = pl->pl_child_pid;
  481 }
  482 #endif /* COMPAT_FREEBSD32 */
  483 
  484 /*
  485  * Process debugging system call.
  486  */
  487 #ifndef _SYS_SYSPROTO_H_
  488 struct ptrace_args {
  489         int     req;
  490         pid_t   pid;
  491         caddr_t addr;
  492         int     data;
  493 };
  494 #endif
  495 
  496 #ifdef COMPAT_FREEBSD32
  497 /*
  498  * This CPP subterfuge is to try and reduce the number of ifdefs in
  499  * the body of the code.
  500  *   COPYIN(uap->addr, &r.reg, sizeof r.reg);
  501  * becomes either:
  502  *   copyin(uap->addr, &r.reg, sizeof r.reg);
  503  * or
  504  *   copyin(uap->addr, &r.reg32, sizeof r.reg32);
  505  * .. except this is done at runtime.
  506  */
  507 #define COPYIN(u, k, s)         wrap32 ? \
  508         copyin(u, k ## 32, s ## 32) : \
  509         copyin(u, k, s)
  510 #define COPYOUT(k, u, s)        wrap32 ? \
  511         copyout(k ## 32, u, s ## 32) : \
  512         copyout(k, u, s)
  513 #else
  514 #define COPYIN(u, k, s)         copyin(u, k, s)
  515 #define COPYOUT(k, u, s)        copyout(k, u, s)
  516 #endif
  517 int
  518 sys_ptrace(struct thread *td, struct ptrace_args *uap)
  519 {
  520         /*
  521          * XXX this obfuscation is to reduce stack usage, but the register
  522          * structs may be too large to put on the stack anyway.
  523          */
  524         union {
  525                 struct ptrace_io_desc piod;
  526                 struct ptrace_lwpinfo pl;
  527                 struct ptrace_vm_entry pve;
  528                 struct dbreg dbreg;
  529                 struct fpreg fpreg;
  530                 struct reg reg;
  531 #ifdef COMPAT_FREEBSD32
  532                 struct dbreg32 dbreg32;
  533                 struct fpreg32 fpreg32;
  534                 struct reg32 reg32;
  535                 struct ptrace_io_desc32 piod32;
  536                 struct ptrace_lwpinfo32 pl32;
  537                 struct ptrace_vm_entry32 pve32;
  538 #endif
  539         } r;
  540         void *addr;
  541         int error = 0;
  542 #ifdef COMPAT_FREEBSD32
  543         int wrap32 = 0;
  544 
  545         if (SV_CURPROC_FLAG(SV_ILP32))
  546                 wrap32 = 1;
  547 #endif
  548         AUDIT_ARG_PID(uap->pid);
  549         AUDIT_ARG_CMD(uap->req);
  550         AUDIT_ARG_VALUE(uap->data);
  551         addr = &r;
  552         switch (uap->req) {
  553         case PT_GETREGS:
  554         case PT_GETFPREGS:
  555         case PT_GETDBREGS:
  556         case PT_LWPINFO:
  557                 break;
  558         case PT_SETREGS:
  559                 error = COPYIN(uap->addr, &r.reg, sizeof r.reg);
  560                 break;
  561         case PT_SETFPREGS:
  562                 error = COPYIN(uap->addr, &r.fpreg, sizeof r.fpreg);
  563                 break;
  564         case PT_SETDBREGS:
  565                 error = COPYIN(uap->addr, &r.dbreg, sizeof r.dbreg);
  566                 break;
  567         case PT_IO:
  568                 error = COPYIN(uap->addr, &r.piod, sizeof r.piod);
  569                 break;
  570         case PT_VM_ENTRY:
  571                 error = COPYIN(uap->addr, &r.pve, sizeof r.pve);
  572                 break;
  573         default:
  574                 addr = uap->addr;
  575                 break;
  576         }
  577         if (error)
  578                 return (error);
  579 
  580         error = kern_ptrace(td, uap->req, uap->pid, addr, uap->data);
  581         if (error)
  582                 return (error);
  583 
  584         switch (uap->req) {
  585         case PT_VM_ENTRY:
  586                 error = COPYOUT(&r.pve, uap->addr, sizeof r.pve);
  587                 break;
  588         case PT_IO:
  589                 error = COPYOUT(&r.piod, uap->addr, sizeof r.piod);
  590                 break;
  591         case PT_GETREGS:
  592                 error = COPYOUT(&r.reg, uap->addr, sizeof r.reg);
  593                 break;
  594         case PT_GETFPREGS:
  595                 error = COPYOUT(&r.fpreg, uap->addr, sizeof r.fpreg);
  596                 break;
  597         case PT_GETDBREGS:
  598                 error = COPYOUT(&r.dbreg, uap->addr, sizeof r.dbreg);
  599                 break;
  600         case PT_LWPINFO:
  601                 error = copyout(&r.pl, uap->addr, uap->data);
  602                 break;
  603         }
  604 
  605         return (error);
  606 }
  607 #undef COPYIN
  608 #undef COPYOUT
  609 
  610 #ifdef COMPAT_FREEBSD32
  611 /*
  612  *   PROC_READ(regs, td2, addr);
  613  * becomes either:
  614  *   proc_read_regs(td2, addr);
  615  * or
  616  *   proc_read_regs32(td2, addr);
  617  * .. except this is done at runtime.  There is an additional
  618  * complication in that PROC_WRITE disallows 32 bit consumers
  619  * from writing to 64 bit address space targets.
  620  */
  621 #define PROC_READ(w, t, a)      wrap32 ? \
  622         proc_read_ ## w ## 32(t, a) : \
  623         proc_read_ ## w (t, a)
  624 #define PROC_WRITE(w, t, a)     wrap32 ? \
  625         (safe ? proc_write_ ## w ## 32(t, a) : EINVAL ) : \
  626         proc_write_ ## w (t, a)
  627 #else
  628 #define PROC_READ(w, t, a)      proc_read_ ## w (t, a)
  629 #define PROC_WRITE(w, t, a)     proc_write_ ## w (t, a)
  630 #endif
  631 
  632 int
  633 kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
  634 {
  635         struct iovec iov;
  636         struct uio uio;
  637         struct proc *curp, *p, *pp;
  638         struct thread *td2 = NULL;
  639         struct ptrace_io_desc *piod = NULL;
  640         struct ptrace_lwpinfo *pl;
  641         int error, write, tmp, num;
  642         int proctree_locked = 0;
  643         lwpid_t tid = 0, *buf;
  644 #ifdef COMPAT_FREEBSD32
  645         int wrap32 = 0, safe = 0;
  646         struct ptrace_io_desc32 *piod32 = NULL;
  647         struct ptrace_lwpinfo32 *pl32 = NULL;
  648         struct ptrace_lwpinfo plr;
  649 #endif
  650 
  651         curp = td->td_proc;
  652 
  653         /* Lock proctree before locking the process. */
  654         switch (req) {
  655         case PT_TRACE_ME:
  656         case PT_ATTACH:
  657         case PT_STEP:
  658         case PT_CONTINUE:
  659         case PT_TO_SCE:
  660         case PT_TO_SCX:
  661         case PT_SYSCALL:
  662         case PT_FOLLOW_FORK:
  663         case PT_DETACH:
  664                 sx_xlock(&proctree_lock);
  665                 proctree_locked = 1;
  666                 break;
  667         default:
  668                 break;
  669         }
  670 
  671         write = 0;
  672         if (req == PT_TRACE_ME) {
  673                 p = td->td_proc;
  674                 PROC_LOCK(p);
  675         } else {
  676                 if (pid <= PID_MAX) {
  677                         if ((p = pfind(pid)) == NULL) {
  678                                 if (proctree_locked)
  679                                         sx_xunlock(&proctree_lock);
  680                                 return (ESRCH);
  681                         }
  682                 } else {
  683                         td2 = tdfind(pid, -1);
  684                         if (td2 == NULL) {
  685                                 if (proctree_locked)
  686                                         sx_xunlock(&proctree_lock);
  687                                 return (ESRCH);
  688                         }
  689                         p = td2->td_proc;
  690                         tid = pid;
  691                         pid = p->p_pid;
  692                 }
  693         }
  694         AUDIT_ARG_PROCESS(p);
  695 
  696         if ((p->p_flag & P_WEXIT) != 0) {
  697                 error = ESRCH;
  698                 goto fail;
  699         }
  700         if ((error = p_cansee(td, p)) != 0)
  701                 goto fail;
  702 
  703         if ((error = p_candebug(td, p)) != 0)
  704                 goto fail;
  705 
  706         /*
  707          * System processes can't be debugged.
  708          */
  709         if ((p->p_flag & P_SYSTEM) != 0) {
  710                 error = EINVAL;
  711                 goto fail;
  712         }
  713 
  714         if (tid == 0) {
  715                 if ((p->p_flag & P_STOPPED_TRACE) != 0) {
  716                         KASSERT(p->p_xthread != NULL, ("NULL p_xthread"));
  717                         td2 = p->p_xthread;
  718                 } else {
  719                         td2 = FIRST_THREAD_IN_PROC(p);
  720                 }
  721                 tid = td2->td_tid;
  722         }
  723 
  724 #ifdef COMPAT_FREEBSD32
  725         /*
  726          * Test if we're a 32 bit client and what the target is.
  727          * Set the wrap controls accordingly.
  728          */
  729         if (SV_CURPROC_FLAG(SV_ILP32)) {
  730                 if (SV_PROC_FLAG(td2->td_proc, SV_ILP32))
  731                         safe = 1;
  732                 wrap32 = 1;
  733         }
  734 #endif
  735         /*
  736          * Permissions check
  737          */
  738         switch (req) {
  739         case PT_TRACE_ME:
  740                 /* Always legal. */
  741                 break;
  742 
  743         case PT_ATTACH:
  744                 /* Self */
  745                 if (p->p_pid == td->td_proc->p_pid) {
  746                         error = EINVAL;
  747                         goto fail;
  748                 }
  749 
  750                 /* Already traced */
  751                 if (p->p_flag & P_TRACED) {
  752                         error = EBUSY;
  753                         goto fail;
  754                 }
  755 
  756                 /* Can't trace an ancestor if you're being traced. */
  757                 if (curp->p_flag & P_TRACED) {
  758                         for (pp = curp->p_pptr; pp != NULL; pp = pp->p_pptr) {
  759                                 if (pp == p) {
  760                                         error = EINVAL;
  761                                         goto fail;
  762                                 }
  763                         }
  764                 }
  765 
  766 
  767                 /* OK */
  768                 break;
  769 
  770         case PT_CLEARSTEP:
  771                 /* Allow thread to clear single step for itself */
  772                 if (td->td_tid == tid)
  773                         break;
  774 
  775                 /* FALLTHROUGH */
  776         default:
  777                 /* not being traced... */
  778                 if ((p->p_flag & P_TRACED) == 0) {
  779                         error = EPERM;
  780                         goto fail;
  781                 }
  782 
  783                 /* not being traced by YOU */
  784                 if (p->p_pptr != td->td_proc) {
  785                         error = EBUSY;
  786                         goto fail;
  787                 }
  788 
  789                 /* not currently stopped */
  790                 if ((p->p_flag & (P_STOPPED_SIG | P_STOPPED_TRACE)) == 0 ||
  791                     p->p_suspcount != p->p_numthreads  ||
  792                     (p->p_flag & P_WAITED) == 0) {
  793                         error = EBUSY;
  794                         goto fail;
  795                 }
  796 
  797                 if ((p->p_flag & P_STOPPED_TRACE) == 0) {
  798                         static int count = 0;
  799                         if (count++ == 0)
  800                                 printf("P_STOPPED_TRACE not set.\n");
  801                 }
  802 
  803                 /* OK */
  804                 break;
  805         }
  806 
  807         /* Keep this process around until we finish this request. */
  808         _PHOLD(p);
  809 
  810 #ifdef FIX_SSTEP
  811         /*
  812          * Single step fixup ala procfs
  813          */
  814         FIX_SSTEP(td2);
  815 #endif
  816 
  817         /*
  818          * Actually do the requests
  819          */
  820 
  821         td->td_retval[0] = 0;
  822 
  823         switch (req) {
  824         case PT_TRACE_ME:
  825                 /* set my trace flag and "owner" so it can read/write me */
  826                 p->p_flag |= P_TRACED;
  827                 p->p_oppid = p->p_pptr->p_pid;
  828                 break;
  829 
  830         case PT_ATTACH:
  831                 /* security check done above */
  832                 /*
  833                  * It would be nice if the tracing relationship was separate
  834                  * from the parent relationship but that would require
  835                  * another set of links in the proc struct or for "wait"
  836                  * to scan the entire proc table.  To make life easier,
  837                  * we just re-parent the process we're trying to trace.
  838                  * The old parent is remembered so we can put things back
  839                  * on a "detach".
  840                  */
  841                 p->p_flag |= P_TRACED;
  842                 p->p_oppid = p->p_pptr->p_pid;
  843                 if (p->p_pptr != td->td_proc) {
  844                         /* Remember that a child is being debugged(traced). */
  845                         p->p_pptr->p_dbg_child++;
  846                         proc_reparent(p, td->td_proc);
  847                 }
  848                 data = SIGSTOP;
  849                 goto sendsig;   /* in PT_CONTINUE below */
  850 
  851         case PT_CLEARSTEP:
  852                 error = ptrace_clear_single_step(td2);
  853                 break;
  854 
  855         case PT_SETSTEP:
  856                 error = ptrace_single_step(td2);
  857                 break;
  858 
  859         case PT_SUSPEND:
  860                 td2->td_dbgflags |= TDB_SUSPEND;
  861                 thread_lock(td2);
  862                 td2->td_flags |= TDF_NEEDSUSPCHK;
  863                 thread_unlock(td2);
  864                 break;
  865 
  866         case PT_RESUME:
  867                 td2->td_dbgflags &= ~TDB_SUSPEND;
  868                 break;
  869 
  870         case PT_FOLLOW_FORK:
  871                 if (data)
  872                         p->p_flag |= P_FOLLOWFORK;
  873                 else
  874                         p->p_flag &= ~P_FOLLOWFORK;
  875                 break;
  876 
  877         case PT_STEP:
  878         case PT_CONTINUE:
  879         case PT_TO_SCE:
  880         case PT_TO_SCX:
  881         case PT_SYSCALL:
  882         case PT_DETACH:
  883                 /* Zero means do not send any signal */
  884                 if (data < 0 || data > _SIG_MAXSIG) {
  885                         error = EINVAL;
  886                         break;
  887                 }
  888 
  889                 switch (req) {
  890                 case PT_STEP:
  891                         error = ptrace_single_step(td2);
  892                         if (error)
  893                                 goto out;
  894                         break;
  895                 case PT_CONTINUE:
  896                 case PT_TO_SCE:
  897                 case PT_TO_SCX:
  898                 case PT_SYSCALL:
  899                         if (addr != (void *)1) {
  900                                 error = ptrace_set_pc(td2,
  901                                     (u_long)(uintfptr_t)addr);
  902                                 if (error)
  903                                         goto out;
  904                         }
  905                         switch (req) {
  906                         case PT_TO_SCE:
  907                                 p->p_stops |= S_PT_SCE;
  908                                 break;
  909                         case PT_TO_SCX:
  910                                 p->p_stops |= S_PT_SCX;
  911                                 break;
  912                         case PT_SYSCALL:
  913                                 p->p_stops |= S_PT_SCE | S_PT_SCX;
  914                                 break;
  915                         }
  916                         break;
  917                 case PT_DETACH:
  918                         /* reset process parent */
  919                         if (p->p_oppid != p->p_pptr->p_pid) {
  920                                 struct proc *pp;
  921 
  922                                 PROC_LOCK(p->p_pptr);
  923                                 sigqueue_take(p->p_ksi);
  924                                 PROC_UNLOCK(p->p_pptr);
  925 
  926                                 PROC_UNLOCK(p);
  927                                 pp = pfind(p->p_oppid);
  928                                 if (pp == NULL)
  929                                         pp = initproc;
  930                                 else
  931                                         PROC_UNLOCK(pp);
  932                                 PROC_LOCK(p);
  933                                 proc_reparent(p, pp);
  934                                 p->p_pptr->p_dbg_child--;
  935                                 if (pp == initproc)
  936                                         p->p_sigparent = SIGCHLD;
  937                         }
  938                         p->p_oppid = 0;
  939                         p->p_flag &= ~(P_TRACED | P_WAITED | P_FOLLOWFORK);
  940 
  941                         /* should we send SIGCHLD? */
  942                         /* childproc_continued(p); */
  943                         break;
  944                 }
  945 
  946         sendsig:
  947                 if (proctree_locked) {
  948                         sx_xunlock(&proctree_lock);
  949                         proctree_locked = 0;
  950                 }
  951                 p->p_xstat = data;
  952                 p->p_xthread = NULL;
  953                 if ((p->p_flag & (P_STOPPED_SIG | P_STOPPED_TRACE)) != 0) {
  954                         /* deliver or queue signal */
  955                         td2->td_dbgflags &= ~TDB_XSIG;
  956                         td2->td_xsig = data;
  957 
  958                         if (req == PT_DETACH) {
  959                                 struct thread *td3;
  960                                 FOREACH_THREAD_IN_PROC(p, td3) {
  961                                         td3->td_dbgflags &= ~TDB_SUSPEND; 
  962                                 }
  963                         }
  964                         /*
  965                          * unsuspend all threads, to not let a thread run,
  966                          * you should use PT_SUSPEND to suspend it before
  967                          * continuing process.
  968                          */
  969                         PROC_SLOCK(p);
  970                         p->p_flag &= ~(P_STOPPED_TRACE|P_STOPPED_SIG|P_WAITED);
  971                         thread_unsuspend(p);
  972                         PROC_SUNLOCK(p);
  973                 } else {
  974                         if (data)
  975                                 kern_psignal(p, data);
  976                 }
  977                 break;
  978 
  979         case PT_WRITE_I:
  980         case PT_WRITE_D:
  981                 td2->td_dbgflags |= TDB_USERWR;
  982                 write = 1;
  983                 /* FALLTHROUGH */
  984         case PT_READ_I:
  985         case PT_READ_D:
  986                 PROC_UNLOCK(p);
  987                 tmp = 0;
  988                 /* write = 0 set above */
  989                 iov.iov_base = write ? (caddr_t)&data : (caddr_t)&tmp;
  990                 iov.iov_len = sizeof(int);
  991                 uio.uio_iov = &iov;
  992                 uio.uio_iovcnt = 1;
  993                 uio.uio_offset = (off_t)(uintptr_t)addr;
  994                 uio.uio_resid = sizeof(int);
  995                 uio.uio_segflg = UIO_SYSSPACE;  /* i.e.: the uap */
  996                 uio.uio_rw = write ? UIO_WRITE : UIO_READ;
  997                 uio.uio_td = td;
  998                 error = proc_rwmem(p, &uio);
  999                 if (uio.uio_resid != 0) {
 1000                         /*
 1001                          * XXX proc_rwmem() doesn't currently return ENOSPC,
 1002                          * so I think write() can bogusly return 0.
 1003                          * XXX what happens for short writes?  We don't want
 1004                          * to write partial data.
 1005                          * XXX proc_rwmem() returns EPERM for other invalid
 1006                          * addresses.  Convert this to EINVAL.  Does this
 1007                          * clobber returns of EPERM for other reasons?
 1008                          */
 1009                         if (error == 0 || error == ENOSPC || error == EPERM)
 1010                                 error = EINVAL; /* EOF */
 1011                 }
 1012                 if (!write)
 1013                         td->td_retval[0] = tmp;
 1014                 PROC_LOCK(p);
 1015                 break;
 1016 
 1017         case PT_IO:
 1018 #ifdef COMPAT_FREEBSD32
 1019                 if (wrap32) {
 1020                         piod32 = addr;
 1021                         iov.iov_base = (void *)(uintptr_t)piod32->piod_addr;
 1022                         iov.iov_len = piod32->piod_len;
 1023                         uio.uio_offset = (off_t)(uintptr_t)piod32->piod_offs;
 1024                         uio.uio_resid = piod32->piod_len;
 1025                 } else
 1026 #endif
 1027                 {
 1028                         piod = addr;
 1029                         iov.iov_base = piod->piod_addr;
 1030                         iov.iov_len = piod->piod_len;
 1031                         uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs;
 1032                         uio.uio_resid = piod->piod_len;
 1033                 }
 1034                 uio.uio_iov = &iov;
 1035                 uio.uio_iovcnt = 1;
 1036                 uio.uio_segflg = UIO_USERSPACE;
 1037                 uio.uio_td = td;
 1038 #ifdef COMPAT_FREEBSD32
 1039                 tmp = wrap32 ? piod32->piod_op : piod->piod_op;
 1040 #else
 1041                 tmp = piod->piod_op;
 1042 #endif
 1043                 switch (tmp) {
 1044                 case PIOD_READ_D:
 1045                 case PIOD_READ_I:
 1046                         uio.uio_rw = UIO_READ;
 1047                         break;
 1048                 case PIOD_WRITE_D:
 1049                 case PIOD_WRITE_I:
 1050                         td2->td_dbgflags |= TDB_USERWR;
 1051                         uio.uio_rw = UIO_WRITE;
 1052                         break;
 1053                 default:
 1054                         error = EINVAL;
 1055                         goto out;
 1056                 }
 1057                 PROC_UNLOCK(p);
 1058                 error = proc_rwmem(p, &uio);
 1059 #ifdef COMPAT_FREEBSD32
 1060                 if (wrap32)
 1061                         piod32->piod_len -= uio.uio_resid;
 1062                 else
 1063 #endif
 1064                         piod->piod_len -= uio.uio_resid;
 1065                 PROC_LOCK(p);
 1066                 break;
 1067 
 1068         case PT_KILL:
 1069                 data = SIGKILL;
 1070                 goto sendsig;   /* in PT_CONTINUE above */
 1071 
 1072         case PT_SETREGS:
 1073                 td2->td_dbgflags |= TDB_USERWR;
 1074                 error = PROC_WRITE(regs, td2, addr);
 1075                 break;
 1076 
 1077         case PT_GETREGS:
 1078                 error = PROC_READ(regs, td2, addr);
 1079                 break;
 1080 
 1081         case PT_SETFPREGS:
 1082                 td2->td_dbgflags |= TDB_USERWR;
 1083                 error = PROC_WRITE(fpregs, td2, addr);
 1084                 break;
 1085 
 1086         case PT_GETFPREGS:
 1087                 error = PROC_READ(fpregs, td2, addr);
 1088                 break;
 1089 
 1090         case PT_SETDBREGS:
 1091                 td2->td_dbgflags |= TDB_USERWR;
 1092                 error = PROC_WRITE(dbregs, td2, addr);
 1093                 break;
 1094 
 1095         case PT_GETDBREGS:
 1096                 error = PROC_READ(dbregs, td2, addr);
 1097                 break;
 1098 
 1099         case PT_LWPINFO:
 1100                 if (data <= 0 ||
 1101 #ifdef COMPAT_FREEBSD32
 1102                     (!wrap32 && data > sizeof(*pl)) ||
 1103                     (wrap32 && data > sizeof(*pl32))) {
 1104 #else
 1105                     data > sizeof(*pl)) {
 1106 #endif
 1107                         error = EINVAL;
 1108                         break;
 1109                 }
 1110 #ifdef COMPAT_FREEBSD32
 1111                 if (wrap32) {
 1112                         pl = &plr;
 1113                         pl32 = addr;
 1114                 } else
 1115 #endif
 1116                 pl = addr;
 1117                 pl->pl_lwpid = td2->td_tid;
 1118                 pl->pl_flags = 0;
 1119                 if (td2->td_dbgflags & TDB_XSIG) {
 1120                         pl->pl_event = PL_EVENT_SIGNAL;
 1121                         if (td2->td_dbgksi.ksi_signo != 0 &&
 1122 #ifdef COMPAT_FREEBSD32
 1123                             ((!wrap32 && data >= offsetof(struct ptrace_lwpinfo,
 1124                             pl_siginfo) + sizeof(pl->pl_siginfo)) ||
 1125                             (wrap32 && data >= offsetof(struct ptrace_lwpinfo32,
 1126                             pl_siginfo) + sizeof(struct siginfo32)))
 1127 #else
 1128                             data >= offsetof(struct ptrace_lwpinfo, pl_siginfo)
 1129                             + sizeof(pl->pl_siginfo)
 1130 #endif
 1131                         ){
 1132                                 pl->pl_flags |= PL_FLAG_SI;
 1133                                 pl->pl_siginfo = td2->td_dbgksi.ksi_info;
 1134                         }
 1135                 }
 1136                 if ((pl->pl_flags & PL_FLAG_SI) == 0)
 1137                         bzero(&pl->pl_siginfo, sizeof(pl->pl_siginfo));
 1138                 if (td2->td_dbgflags & TDB_SCE)
 1139                         pl->pl_flags |= PL_FLAG_SCE;
 1140                 else if (td2->td_dbgflags & TDB_SCX)
 1141                         pl->pl_flags |= PL_FLAG_SCX;
 1142                 if (td2->td_dbgflags & TDB_EXEC)
 1143                         pl->pl_flags |= PL_FLAG_EXEC;
 1144                 if (td2->td_dbgflags & TDB_FORK) {
 1145                         pl->pl_flags |= PL_FLAG_FORKED;
 1146                         pl->pl_child_pid = td2->td_dbg_forked;
 1147                 }
 1148                 pl->pl_sigmask = td2->td_sigmask;
 1149                 pl->pl_siglist = td2->td_siglist;
 1150                 strcpy(pl->pl_tdname, td2->td_name);
 1151 #ifdef COMPAT_FREEBSD32
 1152                 if (wrap32)
 1153                         ptrace_lwpinfo_to32(pl, pl32);
 1154 #endif
 1155                 break;
 1156 
 1157         case PT_GETNUMLWPS:
 1158                 td->td_retval[0] = p->p_numthreads;
 1159                 break;
 1160 
 1161         case PT_GETLWPLIST:
 1162                 if (data <= 0) {
 1163                         error = EINVAL;
 1164                         break;
 1165                 }
 1166                 num = imin(p->p_numthreads, data);
 1167                 PROC_UNLOCK(p);
 1168                 buf = malloc(num * sizeof(lwpid_t), M_TEMP, M_WAITOK);
 1169                 tmp = 0;
 1170                 PROC_LOCK(p);
 1171                 FOREACH_THREAD_IN_PROC(p, td2) {
 1172                         if (tmp >= num)
 1173                                 break;
 1174                         buf[tmp++] = td2->td_tid;
 1175                 }
 1176                 PROC_UNLOCK(p);
 1177                 error = copyout(buf, addr, tmp * sizeof(lwpid_t));
 1178                 free(buf, M_TEMP);
 1179                 if (!error)
 1180                         td->td_retval[0] = tmp;
 1181                 PROC_LOCK(p);
 1182                 break;
 1183 
 1184         case PT_VM_TIMESTAMP:
 1185                 td->td_retval[0] = p->p_vmspace->vm_map.timestamp;
 1186                 break;
 1187 
 1188         case PT_VM_ENTRY:
 1189                 PROC_UNLOCK(p);
 1190 #ifdef COMPAT_FREEBSD32
 1191                 if (wrap32)
 1192                         error = ptrace_vm_entry32(td, p, addr);
 1193                 else
 1194 #endif
 1195                 error = ptrace_vm_entry(td, p, addr);
 1196                 PROC_LOCK(p);
 1197                 break;
 1198 
 1199         default:
 1200 #ifdef __HAVE_PTRACE_MACHDEP
 1201                 if (req >= PT_FIRSTMACH) {
 1202                         PROC_UNLOCK(p);
 1203                         error = cpu_ptrace(td2, req, addr, data);
 1204                         PROC_LOCK(p);
 1205                 } else
 1206 #endif
 1207                         /* Unknown request. */
 1208                         error = EINVAL;
 1209                 break;
 1210         }
 1211 
 1212 out:
 1213         /* Drop our hold on this process now that the request has completed. */
 1214         _PRELE(p);
 1215 fail:
 1216         PROC_UNLOCK(p);
 1217         if (proctree_locked)
 1218                 sx_xunlock(&proctree_lock);
 1219         return (error);
 1220 }
 1221 #undef PROC_READ
 1222 #undef PROC_WRITE
 1223 
 1224 /*
 1225  * Stop a process because of a debugging event;
 1226  * stay stopped until p->p_step is cleared
 1227  * (cleared by PIOCCONT in procfs).
 1228  */
 1229 void
 1230 stopevent(struct proc *p, unsigned int event, unsigned int val)
 1231 {
 1232 
 1233         PROC_LOCK_ASSERT(p, MA_OWNED);
 1234         p->p_step = 1;
 1235         do {
 1236                 p->p_xstat = val;
 1237                 p->p_xthread = NULL;
 1238                 p->p_stype = event;     /* Which event caused the stop? */
 1239                 wakeup(&p->p_stype);    /* Wake up any PIOCWAIT'ing procs */
 1240                 msleep(&p->p_step, &p->p_mtx, PWAIT, "stopevent", 0);
 1241         } while (p->p_step);
 1242 }

Cache object: 20b9d5532b1bd248e0cf62b4c29053dd


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