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2500b869 TL |
1 | #include "../h/param.h" |
2 | #include "../h/systm.h" | |
3 | #include "../h/dir.h" | |
4 | #include "../h/user.h" | |
5 | #include "../h/proc.h" | |
6 | #include "../h/inode.h" | |
7 | #include "../h/reg.h" | |
8 | #include "../h/text.h" | |
9 | #include "../h/seg.h" | |
10 | #include "../h/mtpr.h" | |
11 | #include "../h/page.h" | |
12 | #include "../h/psl.h" | |
13 | ||
14 | /* | |
15 | * Priority for tracing | |
16 | */ | |
17 | #define IPCPRI PZERO | |
18 | ||
19 | /* | |
20 | * Tracing variables. | |
21 | * Used to pass trace command from | |
22 | * parent to child being traced. | |
23 | * This data base cannot be | |
24 | * shared and is locked | |
25 | * per user. | |
26 | */ | |
27 | struct | |
28 | { | |
29 | int ip_lock; | |
30 | int ip_req; | |
31 | int *ip_addr; | |
32 | int ip_data; | |
33 | } ipc; | |
34 | ||
35 | /* | |
36 | * Send the specified signal to | |
37 | * all processes with 'pgrp' as | |
38 | * process group. | |
39 | * Called by tty.c for quits and | |
40 | * interrupts. | |
41 | */ | |
42 | signal(pgrp, sig) | |
43 | register pgrp; | |
44 | { | |
45 | register struct proc *p; | |
46 | ||
47 | if(pgrp == 0) | |
48 | return; | |
49 | for(p = &proc[0]; p < &proc[NPROC]; p++) | |
50 | if(p->p_pgrp == pgrp) | |
51 | psignal(p, sig); | |
52 | } | |
53 | ||
54 | /* | |
55 | * Send the specified signal to | |
56 | * the specified process. | |
57 | */ | |
58 | psignal(p, sig) | |
59 | register struct proc *p; | |
60 | register unsigned sig; | |
61 | { | |
62 | ||
63 | if((unsigned)sig >= NSIG) | |
64 | return; | |
65 | if(sig) | |
66 | p->p_sig |= 1<<(sig-1); | |
67 | if(p->p_pri > PUSER) | |
68 | p->p_pri = PUSER; | |
69 | if(p->p_stat == SSLEEP && p->p_pri > PZERO) | |
70 | setrun(p); | |
71 | } | |
72 | ||
73 | /* | |
74 | * Returns true if the current | |
75 | * process has a signal to process. | |
76 | * This is asked at least once | |
77 | * each time a process enters the | |
78 | * system. | |
79 | * A signal does not do anything | |
80 | * directly to a process; it sets | |
81 | * a flag that asks the process to | |
82 | * do something to itself. | |
83 | */ | |
84 | issig() | |
85 | { | |
86 | register n; | |
87 | register struct proc *p; | |
88 | ||
89 | p = u.u_procp; | |
90 | while(p->p_sig) { | |
91 | n = fsig(p); | |
92 | if((u.u_signal[n]&1) == 0 || (p->p_flag&STRC)) | |
93 | return(n); | |
94 | p->p_sig &= ~(1<<(n-1)); | |
95 | } | |
96 | return(0); | |
97 | } | |
98 | ||
99 | /* | |
100 | * Enter the tracing STOP state. | |
101 | * In this state, the parent is | |
102 | * informed and the process is able to | |
103 | * receive commands from the parent. | |
104 | */ | |
105 | stop() | |
106 | { | |
107 | register struct proc *pp, *cp; | |
108 | ||
109 | loop: | |
110 | cp = u.u_procp; | |
111 | if(cp->p_ppid != 1) | |
112 | for (pp = &proc[0]; pp < &proc[NPROC]; pp++) | |
113 | if (pp->p_pid == cp->p_ppid) { | |
114 | wakeup((caddr_t)pp); | |
115 | cp->p_stat = SSTOP; | |
116 | swtch(); | |
117 | if ((cp->p_flag&STRC)==0 || procxmt()) | |
118 | return; | |
119 | goto loop; | |
120 | } | |
121 | exit(fsig(u.u_procp)); | |
122 | } | |
123 | ||
124 | /* | |
125 | * Perform the action specified by | |
126 | * the current signal. | |
127 | * The usual sequence is: | |
128 | * if(issig()) | |
129 | * psig(); | |
130 | */ | |
131 | psig() | |
132 | { | |
133 | register n, p; | |
134 | register struct proc *rp; | |
135 | ||
136 | rp = u.u_procp; | |
137 | if (rp->p_flag&STRC) | |
138 | stop(); | |
139 | n = fsig(rp); | |
140 | if (n==0) | |
141 | return; | |
142 | rp->p_sig &= ~(1<<(n-1)); | |
143 | if((p=u.u_signal[n]) != 0) { | |
144 | u.u_error = 0; | |
145 | if(n != SIGINS && n != SIGTRC) | |
146 | u.u_signal[n] = 0; | |
147 | sendsig(p, n); | |
148 | return; | |
149 | } | |
150 | switch(n) { | |
151 | ||
152 | case SIGQUIT: | |
153 | case SIGINS: | |
154 | case SIGTRC: | |
155 | case SIGIOT: | |
156 | case SIGEMT: | |
157 | case SIGFPT: | |
158 | case SIGBUS: | |
159 | case SIGSEG: | |
160 | case SIGSYS: | |
161 | if(core()) | |
162 | n += 0200; | |
163 | } | |
164 | exit(n); | |
165 | } | |
166 | ||
167 | /* | |
168 | * find the signal in bit-position | |
169 | * representation in p_sig. | |
170 | */ | |
171 | fsig(p) | |
172 | struct proc *p; | |
173 | { | |
174 | register n, i; | |
175 | ||
176 | n = p->p_sig; | |
177 | for(i=1; i<NSIG; i++) { | |
178 | if(n & 1) | |
179 | return(i); | |
180 | n >>= 1; | |
181 | } | |
182 | return(0); | |
183 | } | |
184 | ||
185 | /* | |
186 | * Create a core image on the file "core" | |
187 | * If you are looking for protection glitches, | |
188 | * there are probably a wealth of them here | |
189 | * when this occurs to a suid command. | |
190 | * | |
191 | * It writes USIZE block of the | |
192 | * user.h area followed by the entire | |
193 | * data+stack segments. | |
194 | */ | |
195 | core() | |
196 | { | |
197 | register struct inode *ip; | |
198 | register s; | |
199 | extern schar(); | |
200 | ||
201 | u.u_error = 0; | |
202 | u.u_dirp = "core"; | |
203 | ip = namei(schar, 1); | |
204 | if(ip == NULL) { | |
205 | if(u.u_error) | |
206 | return(0); | |
207 | ip = maknode(0666); | |
208 | if (ip==NULL) | |
209 | return(0); | |
210 | } | |
211 | if(!access(ip, IWRITE) && | |
212 | (ip->i_mode&IFMT) == IFREG && | |
213 | u.u_uid == u.u_ruid) { | |
214 | itrunc(ip); | |
215 | u.u_offset = 0; | |
216 | u.u_base = (caddr_t)&u; | |
217 | u.u_count = ctob(USIZE); | |
218 | u.u_segflg = 1; | |
219 | writei(ip); | |
220 | s = u.u_procp->p_size - USIZE; | |
221 | estabur((unsigned)0, s, (unsigned)0, 0, RO); | |
222 | u.u_base = 0; | |
223 | u.u_count = ctob(s); | |
224 | u.u_segflg = 0; | |
225 | writei(ip); | |
226 | } | |
227 | iput(ip); | |
228 | return(u.u_error==0); | |
229 | } | |
230 | ||
231 | /* | |
232 | * grow the stack to include the SP | |
233 | * true return if successful. | |
234 | */ | |
235 | ||
236 | grow(sp) | |
237 | unsigned sp; | |
238 | { | |
239 | register si, i; | |
240 | register struct proc *p; | |
241 | register a; | |
242 | ||
243 | if(sp >= USRSTACK-ctob(u.u_ssize)) | |
244 | return(0); | |
245 | si = btoc((USRSTACK-sp)) - u.u_ssize + SINCR; | |
246 | if(si <= 0) | |
247 | return(0); | |
248 | if(estabur(u.u_tsize, u.u_dsize, u.u_ssize+si, u.u_sep, RO)) | |
249 | return(0); | |
250 | p = u.u_procp; | |
251 | expand(p->p_size+si); | |
252 | a = p->p_addr + p->p_size; | |
253 | for(i=u.u_ssize; i; i--) { | |
254 | a--; | |
255 | copyseg(a-si, a); | |
256 | } | |
257 | for(i=si; i; i--) | |
258 | clearseg(--a); | |
259 | u.u_ssize += si; | |
260 | return(1); | |
261 | } | |
262 | ||
263 | /* | |
264 | * sys-trace system call. | |
265 | */ | |
266 | ptrace() | |
267 | { | |
268 | register struct proc *p; | |
269 | register struct a { | |
270 | int req; | |
271 | int pid; | |
272 | int *addr; | |
273 | int data; | |
274 | } *uap; | |
275 | ||
276 | uap = (struct a *)u.u_ap; | |
277 | if (uap->req <= 0) { | |
278 | u.u_procp->p_flag |= STRC; | |
279 | return; | |
280 | } | |
281 | for (p=proc; p < &proc[NPROC]; p++) | |
282 | if (p->p_stat==SSTOP | |
283 | && p->p_pid==uap->pid | |
284 | && p->p_ppid==u.u_procp->p_pid) | |
285 | goto found; | |
286 | u.u_error = ESRCH; | |
287 | return; | |
288 | ||
289 | found: | |
290 | while (ipc.ip_lock) | |
291 | sleep((caddr_t)&ipc, IPCPRI); | |
292 | ipc.ip_lock = p->p_pid; | |
293 | ipc.ip_data = uap->data; | |
294 | ipc.ip_addr = uap->addr; | |
295 | ipc.ip_req = uap->req; | |
296 | p->p_flag &= ~SWTED; | |
297 | setrun(p); | |
298 | while (ipc.ip_req > 0) | |
299 | sleep((caddr_t)&ipc, IPCPRI); | |
300 | u.u_r.r_val1 = ipc.ip_data; | |
301 | if (ipc.ip_req < 0) | |
302 | u.u_error = EIO; | |
303 | ipc.ip_lock = 0; | |
304 | wakeup((caddr_t)&ipc); | |
305 | } | |
306 | ||
307 | int ipcreg[] = {R0, R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, AP, FP, SP, PC}; | |
308 | /* | |
309 | * Code that the child process | |
310 | * executes to implement the command | |
311 | * of the parent process in tracing. | |
312 | */ | |
313 | procxmt() | |
314 | { | |
315 | register int i; | |
316 | register *p; | |
317 | register struct text *xp; | |
318 | ||
319 | if (ipc.ip_lock != u.u_procp->p_pid) | |
320 | return(0); | |
321 | i = ipc.ip_req; | |
322 | ipc.ip_req = 0; | |
323 | wakeup((caddr_t)&ipc); | |
324 | switch (i) { | |
325 | ||
326 | /* read user I */ | |
327 | case 1: | |
328 | if ( !useracc((caddr_t)ipc.ip_addr, 4, 1)) | |
329 | goto error; | |
330 | ipc.ip_data = fuiword((caddr_t)ipc.ip_addr); | |
331 | break; | |
332 | ||
333 | /* read user D */ | |
334 | case 2: | |
335 | if ( !useracc((caddr_t)ipc.ip_addr, 4, 1)) | |
336 | goto error; | |
337 | ipc.ip_data = fuword((caddr_t)ipc.ip_addr); | |
338 | break; | |
339 | ||
340 | /* read u */ | |
341 | case 3: | |
342 | i = (int)ipc.ip_addr; | |
343 | if (i<0 || i >= ctob(USIZE)) | |
344 | goto error; | |
345 | ipc.ip_data = ((physadr)&u)->r[i>>2]; | |
346 | break; | |
347 | ||
348 | /* write user I */ | |
349 | /* Must set up to allow writing */ | |
350 | case 4: | |
351 | /* | |
352 | * If text, must assure exclusive use | |
353 | */ | |
354 | if (xp = u.u_procp->p_textp) { | |
355 | if (xp->x_count!=1 || xp->x_iptr->i_mode&ISVTX) | |
356 | goto error; | |
357 | xp->x_iptr->i_flag &= ~ITEXT; | |
358 | } | |
359 | estabur(u.u_tsize, u.u_dsize, u.u_ssize, u.u_sep, RW); | |
360 | i = suiword((caddr_t)ipc.ip_addr, 0); | |
361 | suiword((caddr_t)ipc.ip_addr, ipc.ip_data); | |
362 | estabur(u.u_tsize, u.u_dsize, u.u_ssize, u.u_sep, RO); | |
363 | if (i<0) | |
364 | goto error; | |
365 | if (xp) | |
366 | xp->x_flag |= XWRIT; | |
367 | break; | |
368 | ||
369 | /* write user D */ | |
370 | case 5: | |
371 | if (suword((caddr_t)ipc.ip_addr, 0) < 0) | |
372 | goto error; | |
373 | suword((caddr_t)ipc.ip_addr, ipc.ip_data); | |
374 | break; | |
375 | ||
376 | /* write u */ | |
377 | case 6: | |
378 | i = (int)ipc.ip_addr; | |
379 | p = (int *)&((physadr)&u)->r[i>>2]; | |
380 | for (i=0; i<16; i++) | |
381 | if (p == &u.u_ar0[ipcreg[i]]) | |
382 | goto ok; | |
383 | if (p == &u.u_ar0[PS]) { | |
384 | ipc.ip_data |= 0x3c00000; /* modes == user */ | |
385 | ipc.ip_data &= ~0x3c20ff00; /* IS, FPD, ... */ | |
386 | goto ok; | |
387 | } | |
388 | goto error; | |
389 | ||
390 | ok: | |
391 | *p = ipc.ip_data; | |
392 | break; | |
393 | ||
394 | /* set signal and continue */ | |
395 | /* one version causes a trace-trap */ | |
396 | case 9: | |
397 | u.u_ar0[PS] |= PSL_T; | |
398 | case 7: | |
399 | if ((int)ipc.ip_addr != 1) | |
400 | u.u_ar0[PC] = (int)ipc.ip_addr; | |
401 | u.u_procp->p_sig = 0; | |
402 | if (ipc.ip_data) | |
403 | psignal(u.u_procp, ipc.ip_data); | |
404 | return(1); | |
405 | ||
406 | /* force exit */ | |
407 | case 8: | |
408 | exit(fsig(u.u_procp)); | |
409 | ||
410 | default: | |
411 | error: | |
412 | ipc.ip_req = -1; | |
413 | } | |
414 | return(0); | |
415 | } |