| 1 | /* |
| 2 | * Copyright (c) 1982, 1986, 1989 Regents of the University of California. |
| 3 | * All rights reserved. The Berkeley software License Agreement |
| 4 | * specifies the terms and conditions for redistribution. |
| 5 | * |
| 6 | * @(#)sys_process.c 7.6 (Berkeley) %G% |
| 7 | */ |
| 8 | |
| 9 | #define IPCREG |
| 10 | #include "param.h" |
| 11 | #include "user.h" |
| 12 | #include "proc.h" |
| 13 | #include "vnode.h" |
| 14 | #include "text.h" |
| 15 | #include "seg.h" |
| 16 | #include "buf.h" |
| 17 | #include "ptrace.h" |
| 18 | |
| 19 | #include "machine/reg.h" |
| 20 | #include "machine/psl.h" |
| 21 | #include "machine/pte.h" |
| 22 | |
| 23 | /* |
| 24 | * Priority for tracing |
| 25 | */ |
| 26 | #define IPCPRI PZERO |
| 27 | |
| 28 | /* |
| 29 | * Tracing variables. |
| 30 | * Used to pass trace command from |
| 31 | * parent to child being traced. |
| 32 | * This data base cannot be |
| 33 | * shared and is locked |
| 34 | * per user. |
| 35 | */ |
| 36 | struct { |
| 37 | int ip_lock; |
| 38 | int ip_req; |
| 39 | int *ip_addr; |
| 40 | int ip_data; |
| 41 | } ipc; |
| 42 | |
| 43 | /* |
| 44 | * sys-trace system call. |
| 45 | */ |
| 46 | ptrace() |
| 47 | { |
| 48 | register struct proc *p; |
| 49 | register struct a { |
| 50 | int req; |
| 51 | int pid; |
| 52 | int *addr; |
| 53 | int data; |
| 54 | } *uap; |
| 55 | |
| 56 | uap = (struct a *)u.u_ap; |
| 57 | if (uap->req <= 0) { |
| 58 | u.u_procp->p_flag |= STRC; |
| 59 | return; |
| 60 | } |
| 61 | p = pfind(uap->pid); |
| 62 | if (p == 0 || p->p_stat != SSTOP || p->p_ppid != u.u_procp->p_pid || |
| 63 | !(p->p_flag & STRC)) { |
| 64 | u.u_error = ESRCH; |
| 65 | return; |
| 66 | } |
| 67 | while (ipc.ip_lock) |
| 68 | sleep((caddr_t)&ipc, IPCPRI); |
| 69 | ipc.ip_lock = p->p_pid; |
| 70 | ipc.ip_data = uap->data; |
| 71 | ipc.ip_addr = uap->addr; |
| 72 | ipc.ip_req = uap->req; |
| 73 | p->p_flag &= ~SWTED; |
| 74 | while (ipc.ip_req > 0) { |
| 75 | if (p->p_stat==SSTOP) |
| 76 | setrun(p); |
| 77 | sleep((caddr_t)&ipc, IPCPRI); |
| 78 | } |
| 79 | u.u_r.r_val1 = ipc.ip_data; |
| 80 | if (ipc.ip_req < 0) |
| 81 | u.u_error = EIO; |
| 82 | ipc.ip_lock = 0; |
| 83 | wakeup((caddr_t)&ipc); |
| 84 | } |
| 85 | |
| 86 | #define PHYSOFF(p, o) \ |
| 87 | ((physadr)(p)+((o)/sizeof(((physadr)0)->r[0]))) |
| 88 | |
| 89 | /* |
| 90 | * Code that the child process |
| 91 | * executes to implement the command |
| 92 | * of the parent process in tracing. |
| 93 | */ |
| 94 | procxmt() |
| 95 | { |
| 96 | register int i; |
| 97 | register *p; |
| 98 | register struct text *xp; |
| 99 | struct vattr vattr; |
| 100 | struct vnode *vp; |
| 101 | |
| 102 | if (ipc.ip_lock != u.u_procp->p_pid) |
| 103 | return (0); |
| 104 | u.u_procp->p_slptime = 0; |
| 105 | i = ipc.ip_req; |
| 106 | ipc.ip_req = 0; |
| 107 | switch (i) { |
| 108 | |
| 109 | case PT_READ_I: /* read the child's text space */ |
| 110 | if (!useracc((caddr_t)ipc.ip_addr, 4, B_READ)) |
| 111 | goto error; |
| 112 | ipc.ip_data = fuiword((caddr_t)ipc.ip_addr); |
| 113 | break; |
| 114 | |
| 115 | case PT_READ_D: /* read the child's data space */ |
| 116 | if (!useracc((caddr_t)ipc.ip_addr, 4, B_READ)) |
| 117 | goto error; |
| 118 | ipc.ip_data = fuword((caddr_t)ipc.ip_addr); |
| 119 | break; |
| 120 | |
| 121 | case PT_READ_U: /* read the child's u. */ |
| 122 | i = (int)ipc.ip_addr; |
| 123 | if (i<0 || i >= ctob(UPAGES)) |
| 124 | goto error; |
| 125 | ipc.ip_data = *(int *)PHYSOFF(&u, i); |
| 126 | break; |
| 127 | |
| 128 | case PT_WRITE_I: /* write the child's text space */ |
| 129 | /* |
| 130 | * If text, must assure exclusive use |
| 131 | */ |
| 132 | if (xp = u.u_procp->p_textp) { |
| 133 | vp = xp->x_vptr; |
| 134 | VOP_GETATTR(vp, &vattr, u.u_cred); |
| 135 | if (xp->x_count!=1 || (vattr.va_mode & VSVTX)) |
| 136 | goto error; |
| 137 | xp->x_flag |= XTRC; |
| 138 | } |
| 139 | i = -1; |
| 140 | if ((i = suiword((caddr_t)ipc.ip_addr, ipc.ip_data)) < 0) { |
| 141 | if (chgprot((caddr_t)ipc.ip_addr, RW) && |
| 142 | chgprot((caddr_t)ipc.ip_addr+(sizeof(int)-1), RW)) |
| 143 | i = suiword((caddr_t)ipc.ip_addr, ipc.ip_data); |
| 144 | (void) chgprot((caddr_t)ipc.ip_addr, RO); |
| 145 | (void) chgprot((caddr_t)ipc.ip_addr+(sizeof(int)-1), RO); |
| 146 | } |
| 147 | if (i < 0) |
| 148 | goto error; |
| 149 | #if defined(tahoe) |
| 150 | /* make sure the old value is not in cache */ |
| 151 | ckeyrelease(u.u_procp->p_ckey); |
| 152 | u.u_procp->p_ckey = getcodekey(); |
| 153 | #endif |
| 154 | if (xp) { |
| 155 | xp->x_flag |= XWRIT; |
| 156 | #if defined(tahoe) |
| 157 | xp->x_ckey = u.u_procp->p_ckey; |
| 158 | #endif |
| 159 | } |
| 160 | break; |
| 161 | |
| 162 | case PT_WRITE_D: /* write the child's data space */ |
| 163 | if (suword((caddr_t)ipc.ip_addr, 0) < 0) |
| 164 | goto error; |
| 165 | (void) suword((caddr_t)ipc.ip_addr, ipc.ip_data); |
| 166 | break; |
| 167 | |
| 168 | case PT_WRITE_U: /* write the child's u. */ |
| 169 | i = (int)ipc.ip_addr; |
| 170 | p = (int *)PHYSOFF(&u, i); |
| 171 | for (i=0; i<NIPCREG; i++) |
| 172 | if (p == &u.u_ar0[ipcreg[i]]) |
| 173 | goto ok; |
| 174 | if (p == &u.u_ar0[PS]) { |
| 175 | ipc.ip_data |= PSL_USERSET; |
| 176 | ipc.ip_data &= ~PSL_USERCLR; |
| 177 | #ifdef PSL_CM_CLR |
| 178 | if (ipc.ip_data & PSL_CM) |
| 179 | ipc.ip_data &= ~PSL_CM_CLR; |
| 180 | #endif |
| 181 | goto ok; |
| 182 | } |
| 183 | goto error; |
| 184 | |
| 185 | ok: |
| 186 | *p = ipc.ip_data; |
| 187 | break; |
| 188 | |
| 189 | case PT_STEP: /* single step the child */ |
| 190 | case PT_CONTINUE: /* continue the child */ |
| 191 | if ((int)ipc.ip_addr != 1) |
| 192 | u.u_ar0[PC] = (int)ipc.ip_addr; |
| 193 | if ((unsigned)ipc.ip_data > NSIG) |
| 194 | goto error; |
| 195 | u.u_procp->p_cursig = ipc.ip_data; /* see issig */ |
| 196 | if (i == PT_STEP) |
| 197 | u.u_ar0[PS] |= PSL_T; |
| 198 | wakeup((caddr_t)&ipc); |
| 199 | return (1); |
| 200 | |
| 201 | case PT_KILL: /* kill the child process */ |
| 202 | wakeup((caddr_t)&ipc); |
| 203 | exit(u.u_procp->p_cursig); |
| 204 | |
| 205 | default: |
| 206 | error: |
| 207 | ipc.ip_req = -1; |
| 208 | } |
| 209 | wakeup((caddr_t)&ipc); |
| 210 | return (0); |
| 211 | } |