1 #ifndef lint 2 static char sccsid[] = "@(#)access.c 1.1 (Berkeley) 02/25/86"; 3 #endif 4 /* 5 * Adb: access data in file/process address space. 6 * 7 * The routines in this file access referenced data using 8 * the maps to access files, ptrace to access subprocesses, 9 * or the system page tables when debugging the kernel, 10 * to translate virtual to physical addresses. 11 */ 12 13 #include "defs.h" 14 15 MAP txtmap; 16 MAP datmap; 17 INT wtflag; 18 STRING errflg; 19 INT errno; 20 21 L_INT pid; 22 23 /* 24 * Primitives: put a value in a space, get a value from a space 25 * and get a word or byte not returning if an error occurred. 26 */ 27 put(addr, space, value) 28 off_t addr; { (void) access(WT, addr, space, value); } 29 30 u_int 31 get(addr, space) 32 off_t addr; { return (access(RD, addr, space, 0)); }; 33 34 u_int 35 chkget(addr, space) 36 off_t addr; { u_int w = get(addr, space); chkerr(); return(w); } 37 38 u_int 39 bchkget(addr, space) 40 off_t addr; { return (byte(chkget(addr, space))); } 41 42 /* 43 * Read/write according to mode at address addr in i/d space. 44 * Value is quantity to be written, if write. 45 * 46 * This routine decides whether to get the data from the subprocess 47 * address space with ptrace, or to get it from the files being 48 * debugged. 49 * 50 * When the kernel is being debugged with the -k flag we interpret 51 * the system page tables for data space, mapping p0 and p1 addresses 52 * relative to the ``current'' process (as specified by its p_addr in 53 * <p) and mapping system space addresses through the system page tables. 54 */ 55 access(mode, addr, space, value) 56 int mode, space, value; 57 off_t addr; 58 { 59 int rd = mode == RD; 60 int file, w; 61 62 if (space == NSP) 63 return(0); 64 if (pid) { 65 int pmode = (space&DSP?(rd?RDUSER:WDUSER):(rd?RIUSER:WIUSER)); 66 67 w = ptrace(pmode, pid, addr, value); 68 if (errno) 69 rwerr(space); 70 return (w); 71 } 72 w = 0; 73 if (mode==WT && wtflag==0) 74 error("not in write mode"); 75 if (!chkmap(&addr, space)) 76 return (0); 77 file = (space&DSP) ? datmap.ufd : txtmap.ufd; 78 if (kernel && space == DSP) { 79 addr = vtophys(addr); 80 if (addr < 0) 81 return (0); 82 } 83 if (physrw(file, addr, rd ? &w : &value, rd) < 0) 84 rwerr(space); 85 return (w); 86 } 87 88 /* 89 * When looking at kernel data space through /dev/mem or 90 * with a core file, do virtual memory mapping. 91 */ 92 vtophys(addr) 93 off_t addr; 94 { 95 int oldaddr = addr; 96 int v; 97 struct pte pte; 98 99 addr &= ~0xc0000000; 100 v = btop(addr); 101 switch (oldaddr&0xc0000000) { 102 103 case 0xc0000000: 104 /* 105 * In system space get system pte. If 106 * valid or reclaimable then physical address 107 * is combination of its page number and the page 108 * offset of the original address. 109 */ 110 if (v >= slr) 111 goto oor; 112 addr = ((long)(sbr+v)) &~ 0xc0000000; 113 goto simple; 114 115 case 0x80000000: 116 /* 117 * In p2 spce must not be in shadow region. 118 */ 119 if (v < pcb.pcb_p2lr) 120 goto oor; 121 addr = (long)(pcb.pcb_p2br+v); 122 break; 123 124 case 0x40000000: 125 /* 126 * In p1 space everything is verboten (for now). 127 */ 128 goto oor; 129 130 case 0x00000000: 131 /* 132 * In p0 space must not be off end of region. 133 */ 134 if (v >= pcb.pcb_p0lr) 135 goto oor; 136 addr = (long)(pcb.pcb_p0br+v); 137 break; 138 oor: 139 errflg = "address out of segment"; 140 return (-1); 141 } 142 /* 143 * For p0/p1/p2 address, user-level page table should 144 * be in kernel vm. Do second-level indirect by recursing. 145 */ 146 if ((addr & 0xc0000000) != 0xc0000000) { 147 errflg = "bad p0br, p1br, or p2br in pcb"; 148 return (-1); 149 } 150 addr = vtophys(addr); 151 simple: 152 /* 153 * Addr is now address of the pte of the page we 154 * are interested in; get the pte and paste up the 155 * physical address. 156 */ 157 if (physrw(fcor, addr, (int *)&pte, 1) < 0) { 158 errflg = "page table botch"; 159 return (-1); 160 } 161 /* SHOULD CHECK NOT I/O ADDRESS; NEED CPU TYPE! */ 162 if (pte.pg_v == 0 && (pte.pg_fod || pte.pg_pfnum == 0)) { 163 errflg = "page not valid/reclaimable"; 164 return (-1); 165 } 166 return ((long)(ptob(pte.pg_pfnum) + (oldaddr & PGOFSET))); 167 } 168 169 rwerr(space) 170 int space; 171 { 172 173 if (space & DSP) 174 errflg = "data address not found"; 175 else 176 errflg = "text address not found"; 177 } 178 179 physrw(file, addr, aw, rd) 180 off_t addr; 181 int *aw, rd; 182 { 183 184 if (longseek(file,addr)==0 || 185 (rd ? read(file,aw,sizeof(int)) : write(file,aw,sizeof(int))) < 1) 186 return (-1); 187 return (0); 188 } 189 190 chkmap(addr,space) 191 REG L_INT *addr; 192 REG INT space; 193 { 194 REG MAPPTR amap; 195 196 amap=((space&DSP?&datmap:&txtmap)); 197 IF space&STAR ORF !within(*addr,amap->b1,amap->e1) 198 THEN IF within(*addr,amap->b2,amap->e2) 199 THEN *addr += (amap->f2)-(amap->b2); 200 ELSE rwerr(space); return(0); 201 FI 202 ELSE *addr += (amap->f1)-(amap->b1); 203 FI 204 return(1); 205 } 206 207 within(addr,lbd,ubd) 208 u_int addr, lbd, ubd; { return(addr>=lbd && addr<ubd); } 209 210 longseek(f, a) 211 off_t a; { return(lseek(f, a, 0) != -1); } 212