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1.1.1.2 root 1: /*
2: * linux/kernel/sys.c
3: *
4: * (C) 1991 Linus Torvalds
5: */
6:
1.1 root 7: #include <errno.h>
8:
9: #include <linux/sched.h>
10: #include <linux/tty.h>
11: #include <linux/kernel.h>
1.1.1.3 root 12: #include <linux/config.h>
1.1 root 13: #include <asm/segment.h>
14: #include <sys/times.h>
1.1.1.7 root 15: #include <linux/utsname.h>
1.1.1.3 root 16: #include <sys/param.h>
17: #include <sys/resource.h>
1.1.1.6 root 18: #include <linux/string.h>
1.1.1.3 root 19:
1.1.1.4 root 20: /*
21: * this indicates wether you can reboot with ctrl-alt-del: the deault is yes
22: */
23: static int C_A_D = 1;
24:
1.1.1.3 root 25: /*
26: * The timezone where the local system is located. Used as a default by some
27: * programs who obtain this value by using gettimeofday.
28: */
29: struct timezone sys_tz = { 0, 0};
30:
31: extern int session_of_pgrp(int pgrp);
1.1 root 32:
1.1.1.6 root 33: #define PZERO 15
34:
35: static int proc_sel(struct task_struct *p, int which, int who)
36: {
37: switch (which) {
38: case PRIO_PROCESS:
39: if (!who && p == current)
40: return 1;
41: return(p->pid == who);
42: case PRIO_PGRP:
43: if (!who)
44: who = current->pgrp;
45: return(p->pgrp == who);
46: case PRIO_USER:
47: if (!who)
48: who = current->uid;
49: return(p->uid == who);
50: }
51: return 0;
52: }
53:
54: int sys_setpriority(int which, int who, int niceval)
55: {
56: struct task_struct **p;
57: int error = ESRCH;
58: int priority;
59:
60: if (which > 2 || which < 0)
61: return -EINVAL;
62:
63: if ((priority = PZERO - niceval) <= 0)
64: priority = 1;
65:
66: for(p = &LAST_TASK; p > &FIRST_TASK; --p) {
67: if (!*p || !proc_sel(*p, which, who))
68: continue;
69: if ((*p)->uid != current->euid &&
70: (*p)->uid != current->uid && !suser()) {
71: error = EPERM;
72: continue;
73: }
74: if (error == ESRCH)
75: error = 0;
76: if (priority > (*p)->priority && !suser())
77: error = EACCES;
78: else
79: (*p)->priority = priority;
80: }
81: return -error;
82: }
83:
84: int sys_getpriority(int which, int who)
85: {
86: struct task_struct **p;
87: int max_prio = 0;
88:
89: if (which > 2 || which < 0)
90: return -EINVAL;
91:
92: for(p = &LAST_TASK; p > &FIRST_TASK; --p) {
93: if (!*p || !proc_sel(*p, which, who))
94: continue;
95: if ((*p)->priority > max_prio)
96: max_prio = (*p)->priority;
97: }
98: return(max_prio ? max_prio : -ESRCH);
99: }
100:
101: int sys_profil()
102: {
103: return -ENOSYS;
104: }
105:
1.1 root 106: int sys_ftime()
107: {
108: return -ENOSYS;
109: }
110:
111: int sys_break()
112: {
113: return -ENOSYS;
114: }
115:
1.1.1.4 root 116: int sys_stty()
1.1 root 117: {
118: return -ENOSYS;
119: }
120:
1.1.1.4 root 121: int sys_gtty()
1.1 root 122: {
123: return -ENOSYS;
124: }
125:
1.1.1.4 root 126: int sys_prof()
1.1 root 127: {
128: return -ENOSYS;
129: }
130:
1.1.1.4 root 131: extern void hard_reset_now(void);
132:
133: /*
134: * Reboot system call: for obvious reasons only root may call it,
135: * and even root needs to set up some magic numbers in the registers
136: * so that some mistake won't make this reboot the whole machine.
137: * You can also set the meaning of the ctrl-alt-del-key here.
138: *
139: * reboot doesn't sync: do that yourself before calling this.
140: */
141: int sys_reboot(int magic, int magic_too, int flag)
1.1 root 142: {
1.1.1.4 root 143: if (!suser())
144: return -EPERM;
145: if (magic != 0xfee1dead || magic_too != 672274793)
146: return -EINVAL;
147: if (flag == 0x01234567)
148: hard_reset_now();
149: else if (flag == 0x89ABCDEF)
150: C_A_D = 1;
151: else if (!flag)
152: C_A_D = 0;
153: else
154: return -EINVAL;
155: return (0);
1.1 root 156: }
157:
1.1.1.4 root 158: /*
159: * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
160: * As it's called within an interrupt, it may NOT sync: the only choice
161: * is wether to reboot at once, or just ignore the ctrl-alt-del.
162: */
163: void ctrl_alt_del(void)
1.1 root 164: {
1.1.1.4 root 165: if (C_A_D)
166: hard_reset_now();
1.1.1.8 ! root 167: else
! 168: if (task[1])
! 169: send_sig(SIGINT,task[1],1);
1.1 root 170: }
1.1.1.4 root 171:
1.1 root 172:
1.1.1.3 root 173: /*
174: * This is done BSD-style, with no consideration of the saved gid, except
175: * that if you set the effective gid, it sets the saved gid too. This
176: * makes it possible for a setgid program to completely drop its privileges,
177: * which is often a useful assertion to make when you are doing a security
178: * audit over a program.
179: *
180: * The general idea is that a program which uses just setregid() will be
181: * 100% compatible with BSD. A program which uses just setgid() will be
182: * 100% compatible with POSIX w/ Saved ID's.
183: */
1.1.1.2 root 184: int sys_setregid(int rgid, int egid)
1.1 root 185: {
1.1.1.7 root 186: if (rgid >= 0) {
1.1.1.2 root 187: if ((current->gid == rgid) ||
188: suser())
189: current->gid = rgid;
190: else
191: return(-EPERM);
192: }
1.1.1.7 root 193: if (egid >= 0) {
1.1.1.2 root 194: if ((current->gid == egid) ||
195: (current->egid == egid) ||
1.1.1.3 root 196: suser()) {
1.1.1.2 root 197: current->egid = egid;
1.1.1.3 root 198: current->sgid = egid;
199: } else
1.1.1.2 root 200: return(-EPERM);
201: }
1.1 root 202: return 0;
203: }
204:
1.1.1.3 root 205: /*
206: * setgid() is implemeneted like SysV w/ SAVED_IDS
207: */
1.1.1.2 root 208: int sys_setgid(int gid)
209: {
1.1.1.3 root 210: if (suser())
211: current->gid = current->egid = current->sgid = gid;
212: else if ((gid == current->gid) || (gid == current->sgid))
213: current->egid = gid;
214: else
215: return -EPERM;
216: return 0;
1.1.1.2 root 217: }
218:
1.1 root 219: int sys_acct()
220: {
221: return -ENOSYS;
222: }
223:
224: int sys_phys()
225: {
226: return -ENOSYS;
227: }
228:
229: int sys_lock()
230: {
231: return -ENOSYS;
232: }
233:
234: int sys_mpx()
235: {
236: return -ENOSYS;
237: }
238:
239: int sys_ulimit()
240: {
241: return -ENOSYS;
242: }
243:
244: int sys_time(long * tloc)
245: {
246: int i;
247:
248: i = CURRENT_TIME;
249: if (tloc) {
250: verify_area(tloc,4);
251: put_fs_long(i,(unsigned long *)tloc);
252: }
253: return i;
254: }
255:
1.1.1.2 root 256: /*
257: * Unprivileged users may change the real user id to the effective uid
1.1.1.3 root 258: * or vice versa. (BSD-style)
259: *
260: * When you set the effective uid, it sets the saved uid too. This
261: * makes it possible for a setuid program to completely drop its privileges,
262: * which is often a useful assertion to make when you are doing a security
263: * audit over a program.
264: *
265: * The general idea is that a program which uses just setreuid() will be
266: * 100% compatible with BSD. A program which uses just setuid() will be
267: * 100% compatible with POSIX w/ Saved ID's.
1.1.1.2 root 268: */
269: int sys_setreuid(int ruid, int euid)
1.1 root 270: {
1.1.1.2 root 271: int old_ruid = current->uid;
272:
1.1.1.7 root 273: if (ruid >= 0) {
1.1.1.2 root 274: if ((current->euid==ruid) ||
1.1.1.7 root 275: (old_ruid == ruid) ||
1.1.1.2 root 276: suser())
277: current->uid = ruid;
1.1 root 278: else
1.1.1.2 root 279: return(-EPERM);
280: }
1.1.1.7 root 281: if (euid >= 0) {
1.1.1.2 root 282: if ((old_ruid == euid) ||
1.1.1.7 root 283: (current->euid == euid) ||
1.1.1.3 root 284: suser()) {
1.1.1.2 root 285: current->euid = euid;
1.1.1.3 root 286: current->suid = euid;
287: } else {
1.1.1.2 root 288: current->uid = old_ruid;
289: return(-EPERM);
290: }
291: }
1.1 root 292: return 0;
293: }
294:
1.1.1.3 root 295: /*
296: * setuid() is implemeneted like SysV w/ SAVED_IDS
297: *
298: * Note that SAVED_ID's is deficient in that a setuid root program
299: * like sendmail, for example, cannot set its uid to be a normal
300: * user and then switch back, because if you're root, setuid() sets
301: * the saved uid too. If you don't like this, blame the bright people
302: * in the POSIX commmittee and/or USG. Note that the BSD-style setreuid()
303: * will allow a root program to temporarily drop privileges and be able to
304: * regain them by swapping the real and effective uid.
305: */
1.1.1.2 root 306: int sys_setuid(int uid)
307: {
1.1.1.3 root 308: if (suser())
309: current->uid = current->euid = current->suid = uid;
310: else if ((uid == current->uid) || (uid == current->suid))
311: current->euid = uid;
312: else
313: return -EPERM;
314: return(0);
1.1.1.2 root 315: }
316:
1.1 root 317: int sys_stime(long * tptr)
318: {
1.1.1.2 root 319: if (!suser())
320: return -EPERM;
1.1 root 321: startup_time = get_fs_long((unsigned long *)tptr) - jiffies/HZ;
1.1.1.3 root 322: jiffies_offset = 0;
1.1 root 323: return 0;
324: }
325:
326: int sys_times(struct tms * tbuf)
327: {
1.1.1.2 root 328: if (tbuf) {
329: verify_area(tbuf,sizeof *tbuf);
330: put_fs_long(current->utime,(unsigned long *)&tbuf->tms_utime);
331: put_fs_long(current->stime,(unsigned long *)&tbuf->tms_stime);
332: put_fs_long(current->cutime,(unsigned long *)&tbuf->tms_cutime);
333: put_fs_long(current->cstime,(unsigned long *)&tbuf->tms_cstime);
334: }
1.1 root 335: return jiffies;
336: }
337:
338: int sys_brk(unsigned long end_data_seg)
339: {
340: if (end_data_seg >= current->end_code &&
341: end_data_seg < current->start_stack - 16384)
342: current->brk = end_data_seg;
343: return current->brk;
344: }
345:
346: /*
347: * This needs some heave checking ...
348: * I just haven't get the stomach for it. I also don't fully
349: * understand sessions/pgrp etc. Let somebody who does explain it.
1.1.1.3 root 350: *
351: * OK, I think I have the protection semantics right.... this is really
352: * only important on a multi-user system anyway, to make sure one user
353: * can't send a signal to a process owned by another. -TYT, 12/12/91
1.1 root 354: */
355: int sys_setpgid(int pid, int pgid)
356: {
1.1.1.3 root 357: int i;
1.1 root 358:
359: if (!pid)
360: pid = current->pid;
361: if (!pgid)
1.1.1.2 root 362: pgid = current->pid;
1.1.1.3 root 363: if (pgid < 0)
364: return -EINVAL;
1.1 root 365: for (i=0 ; i<NR_TASKS ; i++)
1.1.1.3 root 366: if (task[i] && (task[i]->pid == pid) &&
367: ((task[i]->p_pptr == current) ||
368: (task[i] == current))) {
1.1 root 369: if (task[i]->leader)
370: return -EPERM;
1.1.1.3 root 371: if ((task[i]->session != current->session) ||
372: ((pgid != pid) &&
373: (session_of_pgrp(pgid) != current->session)))
1.1 root 374: return -EPERM;
375: task[i]->pgrp = pgid;
376: return 0;
377: }
378: return -ESRCH;
379: }
380:
381: int sys_getpgrp(void)
382: {
383: return current->pgrp;
384: }
385:
386: int sys_setsid(void)
387: {
1.1.1.2 root 388: if (current->leader && !suser())
1.1 root 389: return -EPERM;
390: current->leader = 1;
391: current->session = current->pgrp = current->pid;
392: current->tty = -1;
393: return current->pgrp;
394: }
395:
1.1.1.3 root 396: /*
397: * Supplementary group ID's
398: */
399: int sys_getgroups(int gidsetsize, gid_t *grouplist)
400: {
401: int i;
402:
403: if (gidsetsize)
404: verify_area(grouplist, sizeof(gid_t) * gidsetsize);
405:
406: for (i = 0; (i < NGROUPS) && (current->groups[i] != NOGROUP);
407: i++, grouplist++) {
408: if (gidsetsize) {
409: if (i >= gidsetsize)
410: return -EINVAL;
411: put_fs_word(current->groups[i], (short *) grouplist);
412: }
413: }
414: return(i);
415: }
416:
417: int sys_setgroups(int gidsetsize, gid_t *grouplist)
418: {
419: int i;
420:
421: if (!suser())
422: return -EPERM;
423: if (gidsetsize > NGROUPS)
424: return -EINVAL;
425: for (i = 0; i < gidsetsize; i++, grouplist++) {
426: current->groups[i] = get_fs_word((unsigned short *) grouplist);
427: }
428: if (i < NGROUPS)
429: current->groups[i] = NOGROUP;
430: return 0;
431: }
432:
433: int in_group_p(gid_t grp)
434: {
435: int i;
436:
437: if (grp == current->egid)
438: return 1;
439:
440: for (i = 0; i < NGROUPS; i++) {
441: if (current->groups[i] == NOGROUP)
442: break;
443: if (current->groups[i] == grp)
444: return 1;
445: }
446: return 0;
447: }
448:
1.1.1.7 root 449: static struct new_utsname thisname = {
1.1.1.3 root 450: UTS_SYSNAME, UTS_NODENAME, UTS_RELEASE, UTS_VERSION, UTS_MACHINE
451: };
452:
1.1.1.7 root 453: int sys_newuname(struct new_utsname * name)
1.1 root 454: {
1.1.1.7 root 455: if (!name)
456: return -EFAULT;
457: verify_area(name, sizeof *name);
458: memcpy_tofs(name,&thisname,sizeof *name);
459: return 0;
460: }
1.1 root 461:
1.1.1.7 root 462: int sys_uname(struct old_utsname * name)
463: {
1.1.1.6 root 464: if (!name)
465: return -EINVAL;
1.1 root 466: verify_area(name,sizeof *name);
1.1.1.7 root 467: memcpy_tofs(&name->sysname,&thisname.sysname,__OLD_UTS_LEN);
468: put_fs_byte(0,name->sysname+__OLD_UTS_LEN);
469: memcpy_tofs(&name->nodename,&thisname.nodename,__OLD_UTS_LEN);
470: put_fs_byte(0,name->nodename+__OLD_UTS_LEN);
471: memcpy_tofs(&name->release,&thisname.release,__OLD_UTS_LEN);
472: put_fs_byte(0,name->release+__OLD_UTS_LEN);
473: memcpy_tofs(&name->version,&thisname.version,__OLD_UTS_LEN);
474: put_fs_byte(0,name->version+__OLD_UTS_LEN);
475: memcpy_tofs(&name->machine,&thisname.machine,__OLD_UTS_LEN);
476: put_fs_byte(0,name->machine+__OLD_UTS_LEN);
1.1.1.2 root 477: return 0;
1.1 root 478: }
479:
1.1.1.3 root 480: /*
481: * Only sethostname; gethostname can be implemented by calling uname()
482: */
483: int sys_sethostname(char *name, int len)
484: {
485: int i;
486:
487: if (!suser())
488: return -EPERM;
1.1.1.7 root 489: if (len > __NEW_UTS_LEN)
1.1.1.3 root 490: return -EINVAL;
491: for (i=0; i < len; i++) {
492: if ((thisname.nodename[i] = get_fs_byte(name+i)) == 0)
1.1.1.7 root 493: return 0;
1.1.1.3 root 494: }
1.1.1.7 root 495: thisname.nodename[i] = 0;
1.1.1.3 root 496: return 0;
497: }
498:
499: int sys_getrlimit(int resource, struct rlimit *rlim)
500: {
501: if (resource >= RLIM_NLIMITS)
502: return -EINVAL;
503: verify_area(rlim,sizeof *rlim);
504: put_fs_long(current->rlim[resource].rlim_cur,
505: (unsigned long *) rlim);
506: put_fs_long(current->rlim[resource].rlim_max,
507: ((unsigned long *) rlim)+1);
508: return 0;
509: }
510:
511: int sys_setrlimit(int resource, struct rlimit *rlim)
512: {
513: struct rlimit new, *old;
514:
515: if (resource >= RLIM_NLIMITS)
516: return -EINVAL;
517: old = current->rlim + resource;
518: new.rlim_cur = get_fs_long((unsigned long *) rlim);
519: new.rlim_max = get_fs_long(((unsigned long *) rlim)+1);
520: if (((new.rlim_cur > old->rlim_max) ||
521: (new.rlim_max > old->rlim_max)) &&
522: !suser())
523: return -EPERM;
524: *old = new;
525: return 0;
526: }
527:
528: /*
529: * It would make sense to put struct rusuage in the task_struct,
530: * except that would make the task_struct be *really big*. After
531: * task_struct gets moved into malloc'ed memory, it would
532: * make sense to do this. It will make moving the rest of the information
533: * a lot simpler! (Which we're not doing right now because we're not
534: * measuring them yet).
535: */
536: int sys_getrusage(int who, struct rusage *ru)
537: {
538: struct rusage r;
539: unsigned long *lp, *lpend, *dest;
540:
541: if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN)
542: return -EINVAL;
543: verify_area(ru, sizeof *ru);
544: memset((char *) &r, 0, sizeof(r));
545: if (who == RUSAGE_SELF) {
546: r.ru_utime.tv_sec = CT_TO_SECS(current->utime);
547: r.ru_utime.tv_usec = CT_TO_USECS(current->utime);
548: r.ru_stime.tv_sec = CT_TO_SECS(current->stime);
549: r.ru_stime.tv_usec = CT_TO_USECS(current->stime);
1.1.1.5 root 550: r.ru_minflt = current->min_flt;
551: r.ru_majflt = current->maj_flt;
1.1.1.3 root 552: } else {
553: r.ru_utime.tv_sec = CT_TO_SECS(current->cutime);
554: r.ru_utime.tv_usec = CT_TO_USECS(current->cutime);
555: r.ru_stime.tv_sec = CT_TO_SECS(current->cstime);
556: r.ru_stime.tv_usec = CT_TO_USECS(current->cstime);
1.1.1.5 root 557: r.ru_minflt = current->cmin_flt;
558: r.ru_majflt = current->cmaj_flt;
1.1.1.3 root 559: }
560: lp = (unsigned long *) &r;
561: lpend = (unsigned long *) (&r+1);
562: dest = (unsigned long *) ru;
563: for (; lp < lpend; lp++, dest++)
564: put_fs_long(*lp, dest);
565: return(0);
566: }
567:
568: int sys_gettimeofday(struct timeval *tv, struct timezone *tz)
569: {
570: if (tv) {
571: verify_area(tv, sizeof *tv);
572: put_fs_long(startup_time + CT_TO_SECS(jiffies+jiffies_offset),
573: (unsigned long *) tv);
574: put_fs_long(CT_TO_USECS(jiffies+jiffies_offset),
575: ((unsigned long *) tv)+1);
576: }
577: if (tz) {
578: verify_area(tz, sizeof *tz);
579: put_fs_long(sys_tz.tz_minuteswest, (unsigned long *) tz);
580: put_fs_long(sys_tz.tz_dsttime, ((unsigned long *) tz)+1);
581: }
582: return 0;
583: }
584:
585: /*
586: * The first time we set the timezone, we will warp the clock so that
587: * it is ticking GMT time instead of local time. Presumably,
588: * if someone is setting the timezone then we are running in an
589: * environment where the programs understand about timezones.
590: * This should be done at boot time in the /etc/rc script, as
591: * soon as possible, so that the clock can be set right. Otherwise,
592: * various programs will get confused when the clock gets warped.
593: */
594: int sys_settimeofday(struct timeval *tv, struct timezone *tz)
595: {
596: static int firsttime = 1;
597: void adjust_clock();
598:
599: if (!suser())
600: return -EPERM;
601: if (tz) {
602: sys_tz.tz_minuteswest = get_fs_long((unsigned long *) tz);
603: sys_tz.tz_dsttime = get_fs_long(((unsigned long *) tz)+1);
604: if (firsttime) {
605: firsttime = 0;
606: if (!tv)
607: adjust_clock();
608: }
609: }
610: if (tv) {
611: int sec, usec;
612:
613: sec = get_fs_long((unsigned long *)tv);
614: usec = get_fs_long(((unsigned long *)tv)+1);
615:
616: startup_time = sec - jiffies/HZ;
617: jiffies_offset = usec * HZ / 1000000 - jiffies%HZ;
618: }
619: return 0;
620: }
621:
622: /*
623: * Adjust the time obtained from the CMOS to be GMT time instead of
624: * local time.
625: *
626: * This is ugly, but preferable to the alternatives. Otherwise we
627: * would either need to write a program to do it in /etc/rc (and risk
628: * confusion if the program gets run more than once; it would also be
629: * hard to make the program warp the clock precisely n hours) or
630: * compile in the timezone information into the kernel. Bad, bad....
631: *
632: * XXX Currently does not adjust for daylight savings time. May not
633: * need to do anything, depending on how smart (dumb?) the BIOS
634: * is. Blast it all.... the best thing to do not depend on the CMOS
635: * clock at all, but get the time via NTP or timed if you're on a
636: * network.... - TYT, 1/1/92
637: */
638: void adjust_clock()
639: {
640: startup_time += sys_tz.tz_minuteswest*60;
641: }
642:
1.1 root 643: int sys_umask(int mask)
644: {
645: int old = current->umask;
646:
647: current->umask = mask & 0777;
648: return (old);
649: }
1.1.1.3 root 650:
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