1 /* sys_process.c 5.5 82/10/31 */ 2 3 #include "../h/param.h" 4 #include "../h/systm.h" 5 #include "../h/dir.h" 6 #include "../h/user.h" 7 #include "../h/proc.h" 8 #include "../h/inode.h" 9 #include "../h/reg.h" 10 #include "../h/text.h" 11 #include "../h/seg.h" 12 #include "../h/pte.h" 13 #include "../h/psl.h" 14 #include "../h/vm.h" 15 #include "../h/buf.h" 16 #include "../h/acct.h" 17 18 /* 19 * Priority for tracing 20 */ 21 #define IPCPRI PZERO 22 23 /* 24 * Tracing variables. 25 * Used to pass trace command from 26 * parent to child being traced. 27 * This data base cannot be 28 * shared and is locked 29 * per user. 30 */ 31 struct { 32 int ip_lock; 33 int ip_req; 34 int *ip_addr; 35 int ip_data; 36 } ipc; 37 38 /* 39 * sys-trace system call. 40 */ 41 ptrace() 42 { 43 register struct proc *p; 44 register struct a { 45 int req; 46 int pid; 47 int *addr; 48 int data; 49 } *uap; 50 51 uap = (struct a *)u.u_ap; 52 if (uap->req <= 0) { 53 u.u_procp->p_flag |= STRC; 54 return; 55 } 56 p = pfind(uap->pid); 57 if (p == 0 || p->p_stat != SSTOP || p->p_ppid != u.u_procp->p_pid) { 58 u.u_error = ESRCH; 59 return; 60 } 61 while (ipc.ip_lock) 62 sleep((caddr_t)&ipc, IPCPRI); 63 ipc.ip_lock = p->p_pid; 64 ipc.ip_data = uap->data; 65 ipc.ip_addr = uap->addr; 66 ipc.ip_req = uap->req; 67 p->p_flag &= ~SWTED; 68 while (ipc.ip_req > 0) { 69 if (p->p_stat==SSTOP) 70 setrun(p); 71 sleep((caddr_t)&ipc, IPCPRI); 72 } 73 u.u_r.r_val1 = ipc.ip_data; 74 if (ipc.ip_req < 0) 75 u.u_error = EIO; 76 ipc.ip_lock = 0; 77 wakeup((caddr_t)&ipc); 78 } 79 80 #if vax 81 #define NIPCREG 16 82 #endif 83 #if sun 84 #define NIPCREG 17 85 #endif 86 int ipcreg[NIPCREG] = 87 #if vax 88 {R0,R1,R2,R3,R4,R5,R6,R7,R8,R9,R10,R11,AP,FP,SP,PC}; 89 #endif 90 #if sun 91 {R0,R1,R2,R3,R4,R5,R6,R7,AR0,AR1,AR2,AR3,AR4,AR5,AR6,AR7,PC}; 92 #endif 93 94 #define PHYSOFF(p, o) 95 ((physadr)(p)+((o)/sizeof(((physadr)0)->r[0]))) 96 97 /* 98 * Code that the child process 99 * executes to implement the command 100 * of the parent process in tracing. 101 */ 102 procxmt() 103 { 104 register int i; 105 register *p; 106 register struct text *xp; 107 108 if (ipc.ip_lock != u.u_procp->p_pid) 109 return (0); 110 u.u_procp->p_slptime = 0; 111 i = ipc.ip_req; 112 ipc.ip_req = 0; 113 switch (i) { 114 115 /* read user I */ 116 case 1: 117 if (!useracc((caddr_t)ipc.ip_addr, 4, B_READ)) 118 goto error; 119 ipc.ip_data = fuiword((caddr_t)ipc.ip_addr); 120 break; 121 122 /* read user D */ 123 case 2: 124 if (!useracc((caddr_t)ipc.ip_addr, 4, B_READ)) 125 goto error; 126 ipc.ip_data = fuword((caddr_t)ipc.ip_addr); 127 break; 128 129 /* read u */ 130 case 3: 131 i = (int)ipc.ip_addr; 132 if (i<0 || i >= ctob(UPAGES)) 133 goto error; 134 ipc.ip_data = *(int *)PHYSOFF(&u, i); 135 break; 136 137 /* write user I */ 138 /* Must set up to allow writing */ 139 case 4: 140 /* 141 * If text, must assure exclusive use 142 */ 143 if (xp = u.u_procp->p_textp) { 144 if (xp->x_count!=1 || xp->x_iptr->i_mode&ISVTX) 145 goto error; 146 xp->x_iptr->i_flag &= ~ITEXT; 147 } 148 i = -1; 149 if ((i = suiword((caddr_t)ipc.ip_addr, ipc.ip_data)) < 0) { 150 if (chgprot((caddr_t)ipc.ip_addr, RW) && 151 chgprot((caddr_t)ipc.ip_addr+(sizeof(int)-1), RW)) 152 i = suiword((caddr_t)ipc.ip_addr, ipc.ip_data); 153 (void) chgprot((caddr_t)ipc.ip_addr, RO); 154 (void) chgprot((caddr_t)ipc.ip_addr+(sizeof(int)-1), RO); 155 } 156 if (i < 0) 157 goto error; 158 if (xp) 159 xp->x_flag |= XWRIT; 160 break; 161 162 /* write user D */ 163 case 5: 164 if (suword((caddr_t)ipc.ip_addr, 0) < 0) 165 goto error; 166 (void) suword((caddr_t)ipc.ip_addr, ipc.ip_data); 167 break; 168 169 /* write u */ 170 case 6: 171 i = (int)ipc.ip_addr; 172 p = (int *)PHYSOFF(&u, i); 173 for (i=0; i<NIPCREG; i++) 174 if (p == &u.u_ar0[ipcreg[i]]) 175 goto ok; 176 if (p == &u.u_ar0[PS]) { 177 ipc.ip_data |= PSL_USERSET; 178 ipc.ip_data &= ~PSL_USERCLR; 179 goto ok; 180 } 181 goto error; 182 183 ok: 184 *p = ipc.ip_data; 185 break; 186 187 /* set signal and continue */ 188 /* one version causes a trace-trap */ 189 case 9: 190 case 7: 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 == 9) 197 u.u_ar0[PS] |= PSL_T; 198 wakeup((caddr_t)&ipc); 199 return (1); 200 201 /* force exit */ 202 case 8: 203 wakeup((caddr_t)&ipc); 204 exit(u.u_procp->p_cursig); 205 206 default: 207 error: 208 ipc.ip_req = -1; 209 } 210 wakeup((caddr_t)&ipc); 211 return (0); 212 } 213