cae36a52 |
1 | #include <u.h> |
2 | #include <libc.h> |
3 | #include <ureg.h> |
4 | #include <tos.h> |
5 | #include "dat.h" |
6 | #include "fns.h" |
7 | #include "linux.h" |
8 | |
9 | typedef struct Elfhdr Elfhdr; |
10 | typedef struct Proghdr Proghdr; |
11 | typedef struct ElfEx ElfEx; |
12 | |
13 | struct Elfhdr { |
14 | uchar ident[16]; |
15 | ushort type; |
16 | ushort machine; |
17 | ulong version; |
18 | ulong entry; |
19 | ulong phoff; |
20 | ulong shoff; |
21 | ulong flags; |
22 | ushort ehsize; |
23 | ushort phentsize; |
24 | ushort phnum; |
25 | ushort shentsize; |
26 | ushort shnum; |
27 | ushort shstrndx; |
28 | }; |
29 | |
30 | struct Proghdr { |
31 | ulong type; |
32 | ulong offset; |
33 | ulong vaddr; |
34 | ulong paddr; |
35 | ulong filesz; |
36 | ulong memsz; |
37 | ulong flags; |
38 | ulong align; |
39 | }; |
40 | |
41 | struct ElfEx |
42 | { |
43 | ulong ientry; |
44 | ulong ibase; |
45 | |
46 | ulong entry; |
47 | ulong base; |
48 | |
49 | ulong phdr; |
50 | ulong phnum; |
51 | ulong phent; |
52 | }; |
53 | |
54 | static void |
55 | padzero(ulong addr) |
56 | { |
57 | ulong n; |
58 | |
59 | if(n = (pagealign(addr) - addr)) |
60 | memset((void*)addr, 0, n); |
61 | } |
62 | |
63 | enum { |
64 | /* file types */ |
65 | ElfTNone = 0, |
66 | ElfTReloc = 1, |
67 | ElfTExec = 2, |
68 | ElfTShared = 3, |
69 | ElfTCore = 4, |
70 | ElfTMax = 5, |
71 | |
72 | /* machine architectures */ |
73 | ElfMNone = 0, |
74 | ElfM32 = 1, |
75 | ElfMSparc = 2, |
76 | ElfM386 = 3, |
77 | ElfM68 = 4, |
78 | ElfM88 = 5, |
79 | ElfM860 = 7, |
80 | ElfMMips = 8, |
81 | ElfMMax = 9, |
82 | |
83 | /* program segment types */ |
84 | ElfPNull = 0, |
85 | ElfPLoad = 1, |
86 | ElfPDynamic = 2, |
87 | ElfPInterp = 3, |
88 | ElfPNote = 4, |
89 | ElfPShlib = 5, |
90 | ElfPPhdr = 6, |
91 | ElfPMax = 7, |
92 | |
93 | /* program segment flags */ |
94 | ElfPFX = 1, |
95 | ElfPFW = 2, |
96 | ElfPFR = 4, |
97 | }; |
98 | |
99 | static int |
100 | loadelf(char *file, ElfEx *ex, int depth) |
101 | { |
102 | int fd; |
103 | int i, l; |
104 | int mapprot; |
105 | int mapflags; |
106 | ulong mapbase; |
107 | ulong loadaddr; |
108 | ulong bss; |
109 | |
110 | Elfhdr hdr; |
111 | Proghdr *phdr; |
112 | char *interpreter; |
113 | |
114 | interpreter = nil; |
115 | phdr = nil; |
116 | |
117 | if((fd = sys_open(file, O_RDONLY, 0)) < 0){ |
118 | werrstr("cant open %s", file); |
119 | goto errout; |
120 | } |
121 | |
122 | if(sys_read(fd, &hdr, sizeof(hdr)) != sizeof(hdr)){ |
123 | werrstr("cant read elf header"); |
124 | goto errout; |
125 | } |
126 | |
127 | if(memcmp(hdr.ident, "\x7fELF", 4)!=0){ |
128 | werrstr("no elf magic"); |
129 | goto errout; |
130 | } |
131 | |
132 | l = hdr.phnum * hdr.phentsize; |
133 | phdr = kmalloc(l); |
134 | sys_lseek(fd, hdr.phoff, 0); |
135 | if(sys_read(fd, phdr, l) != l){ |
136 | werrstr("cant read program headers"); |
137 | goto errout; |
138 | } |
139 | |
140 | loadaddr = 0; |
141 | mapbase = 0; |
142 | mapflags = MAP_PRIVATE; |
143 | if(hdr.type != ElfTShared) |
144 | mapflags |= MAP_FIXED; |
145 | |
146 | trace("loadelf(): phnum=%d", hdr.phnum); |
147 | |
148 | bss = 0; |
149 | for(i=0; i<hdr.phnum; i++){ |
150 | Proghdr *p; |
151 | |
152 | p = &phdr[i]; |
153 | if(p->type == ElfPInterp){ |
154 | if(interpreter){ |
155 | werrstr("multiple interpeter sections"); |
156 | goto errout; |
157 | } |
158 | l = p->filesz; |
159 | |
160 | interpreter = kmalloc(l+1); |
161 | sys_lseek(fd, p->offset, 0); |
162 | if(sys_read(fd, interpreter, l)!=l){ |
163 | werrstr("cant read interpreter section"); |
164 | goto errout; |
165 | } |
166 | interpreter[l] = '\0'; |
167 | } |
168 | |
169 | if(p->type == ElfPLoad){ |
170 | ulong a; |
171 | int diff; |
172 | |
173 | trace("loadelf(): phdr %d: vaddr=%lux memsz=%lux filesz=%lux offset=%lux flags=%lux", |
174 | i, |
175 | p->vaddr, |
176 | p->memsz, |
177 | p->filesz, |
178 | p->offset, |
179 | p->flags); |
180 | |
181 | mapprot = 0; |
182 | if(p->flags & ElfPFR) |
183 | mapprot |= PROT_READ; |
184 | if(p->flags & ElfPFW) |
185 | mapprot |= PROT_WRITE; |
186 | if(p->flags & ElfPFX) |
187 | mapprot |= PROT_EXEC; |
188 | |
189 | if(hdr.entry >= p->vaddr && hdr.entry < p->vaddr + p->memsz) |
190 | mapprot |= PROT_EXEC; |
191 | |
192 | diff = p->vaddr - (p->vaddr & ~(PAGESIZE-1)); |
193 | |
194 | /* have to call mapdata() before we do the first mmap */ |
195 | if(loadaddr == 0 && depth == 0){ |
196 | if(hdr.type == ElfTShared){ |
197 | mapbase = pagealign((ulong)end + 0x4000000); |
198 | mapflags |= MAP_FIXED; |
199 | } |
200 | mapdata((mapbase + p->vaddr) - diff); |
201 | } |
202 | |
203 | a = sys_mmap( |
204 | (mapbase + p->vaddr) - diff, |
205 | p->filesz + diff, |
206 | mapprot, |
207 | mapflags, |
208 | fd, |
209 | (p->offset - diff)/PAGESIZE); |
210 | |
211 | if(((int)a < 0) && ((int)a > -EMAX)){ |
212 | werrstr("mmap failed: %E", (int)a); |
213 | goto errout; |
214 | } |
215 | if(loadaddr == 0) |
216 | loadaddr = a; |
217 | if(hdr.type == ElfTShared && mapbase == 0){ |
218 | mapbase = a + diff; |
219 | mapflags |= MAP_FIXED; |
220 | } |
221 | if(mapprot & PROT_WRITE) |
222 | padzero(mapbase + p->vaddr + p->filesz); |
223 | if(depth == 0) |
224 | if(mapbase + p->vaddr + p->memsz > bss) |
225 | bss = mapbase + p->vaddr + p->memsz; |
226 | } else { |
227 | trace("loadelf(): phdr %d: type=%lux", i, p->type); |
228 | } |
229 | } |
230 | |
231 | ex->base = loadaddr; |
232 | ex->entry = hdr.entry + ((hdr.type == ElfTShared) ? loadaddr : 0); |
233 | |
234 | ex->phdr = loadaddr + hdr.phoff; |
235 | ex->phent = hdr.phentsize; |
236 | ex->phnum = hdr.phnum; |
237 | |
238 | if(depth == 0){ |
239 | sys_brk(pagealign(bss)); |
240 | |
241 | current->codestart = loadaddr; |
242 | current->codeend = bss; |
243 | } |
244 | |
245 | if(interpreter){ |
246 | ElfEx interpex; |
247 | |
248 | if(loadelf(interpreter, &interpex, depth+1) < 0){ |
249 | werrstr("cant load interpreter: %r"); |
250 | goto errout; |
251 | } |
252 | free(interpreter); |
253 | |
254 | ex->ientry = interpex.entry; |
255 | ex->ibase = interpex.base; |
256 | } else { |
257 | ex->ientry = ex->entry; |
258 | ex->ibase = 0; /* no interpreter */ |
259 | } |
260 | |
261 | sys_close(fd); |
262 | free(phdr); |
263 | return 0; |
264 | |
265 | errout: |
266 | if(fd >= 0) |
267 | sys_close(fd); |
268 | free(interpreter); |
269 | free(phdr); |
270 | return -1; |
271 | } |
272 | |
273 | |
274 | enum { |
275 | AT_NULL, |
276 | AT_IGNORE, |
277 | AT_EXECFD, |
278 | AT_PHDR, |
279 | AT_PHENT, |
280 | AT_PHNUM, |
281 | AT_PAGESZ, |
282 | AT_BASE, |
283 | AT_FLAGS, |
284 | AT_ENTRY, |
285 | AT_NOTELF, |
286 | AT_UID, |
287 | AT_EUID, |
288 | AT_GID, |
289 | AT_EGID, |
290 | AT_PLATFORM, |
291 | AT_HWCAP, |
292 | AT_CLKTCK, |
293 | AT_SECURE = 23, |
294 | |
295 | AT_SYSINFO = 32, |
296 | AT_SYSINFO_EHDR = 33, |
297 | }; |
298 | |
299 | static void* |
300 | setupstack(ElfEx *ex, char *argv[], char *envp[]) |
301 | { |
302 | int envc; |
303 | int argc; |
304 | |
305 | char **dargv; |
306 | char **denv; |
307 | |
308 | ulong *stack; |
309 | ulong *p; |
310 | char *x; |
311 | int i, n; |
312 | |
313 | /* |
314 | * calculate the size we need on stack |
315 | */ |
316 | argc=0; |
317 | while(argv && argv[argc]) argc++; |
318 | |
319 | envc=0; |
320 | while(envp && envp[envc]) envc++; |
321 | |
322 | n = 0; |
323 | n += sizeof(ulong); // argc |
324 | n += (argc+1)*sizeof(char*); // argv + nil |
325 | n += (envc+1)*sizeof(char*); // envp + nil |
326 | n += 16*(2*sizeof(ulong)); // aux |
327 | |
328 | for(i=0; i<argc; i++) |
329 | n += (strlen(argv[i])+1); |
330 | for(i=0; i<envc; i++) |
331 | n += (strlen(envp[i])+1); |
332 | |
333 | if(USTACK - n < PAGESIZE){ |
334 | werrstr("too many arguments passed on stack"); |
335 | return nil; |
336 | } |
337 | |
338 | stack = mapstack(USTACK); |
339 | |
340 | if(((int)stack < 0) && ((int)stack > -EMAX)){ |
341 | werrstr("mapstack failed: %E", (int)stack); |
342 | return nil; |
343 | } |
344 | stack = (ulong*)(((ulong)stack - n) & ~7); |
345 | |
346 | current->stackstart = (ulong)stack; |
347 | |
348 | p = stack; |
349 | |
350 | *p++ = argc; |
351 | |
352 | dargv = (char**)p; |
353 | p += (argc + 1); |
354 | |
355 | denv = (char**)p; |
356 | p += (envc + 1); |
357 | |
358 | #define AUXENT(k, v) {p[0]=k; p[1]=v; p+=2;} |
359 | AUXENT(AT_PAGESZ, PAGESIZE); |
360 | AUXENT(AT_CLKTCK, HZ); |
361 | AUXENT(AT_PHDR, ex->phdr); |
362 | AUXENT(AT_PHENT, ex->phent); |
363 | AUXENT(AT_PHNUM, ex->phnum); |
364 | AUXENT(AT_BASE, ex->ibase); |
365 | AUXENT(AT_FLAGS, 0); |
366 | AUXENT(AT_ENTRY, ex->entry); |
367 | AUXENT(AT_UID, current->uid); |
368 | AUXENT(AT_EUID, current->uid); |
369 | AUXENT(AT_GID, current->gid); |
370 | AUXENT(AT_EGID, current->gid); |
371 | AUXENT(AT_NULL, 0); |
372 | AUXENT(AT_NULL, 0); |
373 | AUXENT(AT_NULL, 0); |
374 | AUXENT(AT_NULL, 0); |
375 | #undef AUXENT |
376 | |
377 | x = (char*)p; |
378 | |
379 | for(i=0; i<argc; i++) |
380 | x += (strlen(dargv[i] = strcpy(x, argv[i])) + 1); |
381 | dargv[argc] = 0; |
382 | for(i=0; i<envc; i++) |
383 | x += (strlen(denv[i] = strcpy(x, envp[i])) + 1); |
384 | denv[envc] = 0; |
385 | |
386 | return stack; |
387 | } |
388 | |
389 | static char** |
390 | copystrings(char *a[]) |
391 | { |
392 | char **r; |
393 | char *p; |
394 | int i, n; |
395 | |
396 | if(a == nil) |
397 | return nil; |
398 | i = 0; |
399 | n = sizeof(a[0]); |
400 | while(a[i]){ |
401 | n += sizeof(a[0]) + (strlen(a[i]) + 1); |
402 | i++; |
403 | } |
404 | r = kmalloc(n); |
405 | n = i; |
406 | p = (char*)&r[n+1]; |
407 | for(i=0; i<n; i++) |
408 | p += strlen(r[i] = strcpy(p, a[i]))+1; |
409 | r[n] = 0; |
410 | return r; |
411 | } |
412 | |
413 | static void |
414 | setcomm(char *exe, char *name, char *argv[]) |
415 | { |
416 | char *buf, *p; |
417 | int i, n; |
418 | |
419 | n = strlen(exe) + strlen(name) +2; |
420 | for(i=0; argv[i]; i++) |
421 | n += strlen(argv[i])+1; |
422 | |
423 | buf = kmalloc(n); |
424 | |
425 | p = buf; |
426 | p += strlen(strcpy(p, name)); |
427 | for(i=0; argv[i]; i++){ |
428 | p += strlen(strcpy(p, " ")); |
429 | p += strlen(strcpy(p, argv[i])); |
430 | } |
431 | setprocname(buf); |
432 | |
433 | /* comm contains the full exe name + argv */ |
434 | p = buf; |
435 | p += strlen(strcpy(p, exe)); |
436 | *p++ = 0; |
437 | for(i=0; argv[i]; i++){ |
438 | p += strlen(strcpy(p, argv[i])); |
439 | *p++ = 0; |
440 | } |
441 | *p++ = 0; |
442 | |
443 | free(current->comm); |
444 | current->comm = buf; |
445 | current->ncomm = p - buf; |
446 | } |
447 | |
448 | static void |
449 | clinote(struct Ureg *ureg) |
450 | { |
451 | jmp_buf jmp; |
452 | ulong pc; |
453 | ulong sp; |
454 | ulong ax; |
455 | |
456 | pc = ureg->pc; |
457 | sp = ureg->sp; |
458 | ax = ureg->ax; |
459 | |
460 | if(!setjmp(jmp)) |
461 | notejmp(ureg, jmp, 1); |
462 | |
463 | ureg->pc = pc; |
464 | ureg->sp = sp; |
465 | ureg->ax = ax; |
466 | } |
467 | |
468 | struct kexecveargs |
469 | { |
470 | char *name; |
471 | char **argv; |
472 | char **envp; |
473 | }; |
474 | |
475 | #pragma profile off |
476 | |
477 | static int |
478 | kexecve(void *arg) |
479 | { |
480 | struct kexecveargs *args; |
481 | Ufile *f; |
482 | ElfEx ex; |
483 | Ureg u; |
484 | int r, n; |
485 | char *b, *p, *e, *x, **a; |
486 | void *stack; |
487 | char *name, *exe; |
488 | char **argv; |
489 | char **envp; |
490 | int phase; |
491 | |
492 | args = arg; |
493 | name = args->name; |
494 | argv = args->argv; |
495 | envp = args->envp; |
496 | |
497 | phase = 0; |
498 | n = 8192; |
499 | b = kmalloc(n); |
500 | p = b; |
501 | e = b + n; |
502 | again: |
503 | if(r = sys_access(name, 05)){ |
504 | if(r > 0) |
505 | r = -EACCES; |
506 | goto errout; |
507 | } |
508 | if((r = sys_open(name, O_RDONLY, 0)) < 0) |
509 | goto errout; |
510 | exe = "/dev/null"; |
511 | if(f = fdgetfile(r)){ |
512 | if(f->path != nil){ |
513 | strncpy(p, f->path, e-p); |
514 | p += strlen(exe = p)+1; |
515 | } |
516 | putfile(f); |
517 | } |
518 | n = sys_read(r, p, (e-p)-1); |
519 | sys_close(r); |
520 | |
521 | r = -ENOEXEC; |
522 | if(n < 4) |
523 | goto errout; |
524 | |
525 | if(memcmp(p, "#!", 2) == 0){ |
526 | p[n] = 0; |
527 | |
528 | r = -ENAMETOOLONG; |
529 | if((x = strchr(p, '\n')) == nil) |
530 | goto errout; |
531 | *x = 0; |
532 | |
533 | a = (char**)&x[1]; |
534 | n = (e - (char*)a) / sizeof(a[0]); |
535 | if(n < 2) |
536 | goto errout; |
537 | n = getfields(&p[2], a, n, 1, "\t\r\n "); |
538 | if(n < 1) |
539 | goto errout; |
540 | r = -E2BIG; |
541 | if(&a[n+1] >= (char**)e) |
542 | goto errout; |
543 | a[n++] = name; |
544 | if(argv != nil){ |
545 | argv++; |
546 | while(*argv){ |
547 | if(&a[n+1] >= (char**)e) |
548 | goto errout; |
549 | a[n++] = *argv++; |
550 | } |
551 | } |
552 | a[n++] = 0; |
553 | p = (char*)&a[n]; |
554 | if(e - p < 4) |
555 | goto errout; |
556 | argv = a; |
557 | name = argv[0]; |
558 | |
559 | goto again; |
560 | } |
561 | |
562 | if(memcmp(p, "\x7fELF", 4)!=0) |
563 | goto errout; |
564 | |
565 | /* |
566 | * the contents on envp[] or argv[] maybe stored in b[], stack or bss of the calling linux |
567 | * process that is destroyed on free(b) and exitmem()... so we need to temporary |
568 | * copy them. |
569 | */ |
570 | r = -ENOMEM; |
571 | name = kstrdup(name); |
572 | phase++; |
573 | if(argv) |
574 | argv = copystrings(argv); |
575 | phase++; |
576 | if(envp) |
577 | envp = copystrings(envp); |
578 | phase++; |
579 | |
580 | /* get out of the note before we destroy user stack */ |
581 | if(current->innote){ |
582 | clinote(current->ureg); |
583 | current->innote = 0; |
584 | } |
585 | |
586 | /* this is the point of no return! */ |
587 | qlock(&proctab); |
588 | zapthreads(); |
589 | exitmem(); |
590 | exitsignal(); |
591 | |
592 | initmem(); |
593 | initsignal(); |
594 | inittls(); |
595 | qunlock(&proctab); |
596 | |
597 | closexfds(); |
598 | |
599 | setcomm(exe, name, argv); |
600 | |
601 | if(loadelf(name, &ex, 0) < 0){ |
602 | trace("kexecve(): loadelf failed: %r"); |
603 | goto errout; |
604 | } |
605 | |
606 | if((stack = setupstack(&ex, argv, envp)) == nil){ |
607 | trace("kexecve(): setupstack failed: %r"); |
608 | goto errout; |
609 | } |
610 | |
611 | memset(&u, 0, sizeof(u)); |
612 | u.sp = (ulong)stack; |
613 | u.pc = (ulong)ex.ientry; |
614 | current->ureg = &u; |
615 | current->syscall = nil; |
616 | phase++; |
617 | |
618 | trace("kexecve(): startup pc=%lux sp=%lux", current->ureg->pc, current->ureg->sp); |
619 | |
620 | errout: |
621 | switch(phase){ |
622 | default: free(envp); |
623 | case 2: free(argv); |
624 | case 1: free(name); |
625 | case 0: free(b); |
626 | } |
627 | switch(phase){ |
628 | case 4: retuser(); |
629 | case 3: exitproc(current, SIGKILL, 1); |
630 | } |
631 | return r; |
632 | } |
633 | |
634 | int sys_execve(char *name, char *argv[], char *envp[]) |
635 | { |
636 | struct kexecveargs args; |
637 | |
638 | trace("sys_execve(%s, %p, %p)", name, argv, envp); |
639 | |
640 | args.name = name; |
641 | args.argv = argv; |
642 | args.envp = envp; |
643 | |
644 | return onstack(kstack, kexecve, &args); |
645 | } |
646 | |
647 | #pragma profile on |