| 1 | #include <signal.h> |
| 2 | #include <sys/types.h> |
| 3 | #include <utmp.h> |
| 4 | #include <setjmp.h> |
| 5 | |
| 6 | #define TABSIZ 100 |
| 7 | #define ALL p = &itab[0]; p < &itab[TABSIZ]; p++ |
| 8 | #define EVER ;; |
| 9 | |
| 10 | char shell[] = "/bin/sh"; |
| 11 | char getty[] = "/etc/getty"; |
| 12 | char minus[] = "-"; |
| 13 | char runc[] = "/etc/rc"; |
| 14 | char ifile[] = "/etc/ttys"; |
| 15 | char utmp[] = "/etc/utmp"; |
| 16 | char wtmpf[] = "/usr/adm/wtmp"; |
| 17 | char ctty[] = "/dev/console"; |
| 18 | char dev[] = "/dev/"; |
| 19 | |
| 20 | struct utmp wtmp; |
| 21 | struct |
| 22 | { |
| 23 | char line[8]; |
| 24 | char comn; |
| 25 | char flag; |
| 26 | } line; |
| 27 | struct tab |
| 28 | { |
| 29 | char line[8]; |
| 30 | char comn; |
| 31 | int pid; |
| 32 | } itab[TABSIZ]; |
| 33 | |
| 34 | int fi; |
| 35 | char tty[20]; |
| 36 | jmp_buf sjbuf; |
| 37 | |
| 38 | main() |
| 39 | { |
| 40 | int reset(); |
| 41 | |
| 42 | setjmp(sjbuf); |
| 43 | signal(SIGHUP, reset); |
| 44 | for(EVER) { |
| 45 | shutdown(); |
| 46 | single(); |
| 47 | runcom(); |
| 48 | merge(); |
| 49 | multiple(); |
| 50 | } |
| 51 | } |
| 52 | |
| 53 | shutdown() |
| 54 | { |
| 55 | register i; |
| 56 | register struct tab *p; |
| 57 | |
| 58 | signal(SIGINT, SIG_IGN); |
| 59 | for(ALL) |
| 60 | term(p); |
| 61 | signal(SIGALRM, reset); |
| 62 | alarm(60); |
| 63 | for(i=0; i<5; i++) |
| 64 | kill(-1, SIGKILL); |
| 65 | while(wait((int *)0) != -1) |
| 66 | ; |
| 67 | alarm(0); |
| 68 | signal(SIGALRM, SIG_DFL); |
| 69 | for(i=0; i<10; i++) |
| 70 | close(i); |
| 71 | } |
| 72 | |
| 73 | single() |
| 74 | { |
| 75 | register pid; |
| 76 | |
| 77 | pid = fork(); |
| 78 | if(pid == 0) { |
| 79 | /* |
| 80 | alarm(300); |
| 81 | */ |
| 82 | signal(SIGHUP, SIG_DFL); |
| 83 | signal(SIGINT, SIG_DFL); |
| 84 | signal(SIGALRM, SIG_DFL); |
| 85 | open(ctty, 2); |
| 86 | dup(0); |
| 87 | dup(0); |
| 88 | execl(shell, minus, (char *)0); |
| 89 | exit(0); |
| 90 | } |
| 91 | while(wait((int *)0) != pid) |
| 92 | ; |
| 93 | } |
| 94 | |
| 95 | runcom() |
| 96 | { |
| 97 | register pid; |
| 98 | |
| 99 | pid = fork(); |
| 100 | if(pid == 0) { |
| 101 | open("/", 0); |
| 102 | dup(0); |
| 103 | dup(0); |
| 104 | execl(shell, shell, runc, (char *)0); |
| 105 | exit(0); |
| 106 | } |
| 107 | while(wait((int *)0) != pid) |
| 108 | ; |
| 109 | } |
| 110 | |
| 111 | multiple() |
| 112 | { |
| 113 | register struct tab *p; |
| 114 | register pid; |
| 115 | |
| 116 | for(EVER) { |
| 117 | pid = wait((int *)0); |
| 118 | if(pid == -1) |
| 119 | return; |
| 120 | for(ALL) |
| 121 | if(p->pid == pid || p->pid == -1) { |
| 122 | rmut(p); |
| 123 | dfork(p); |
| 124 | } |
| 125 | } |
| 126 | } |
| 127 | |
| 128 | term(p) |
| 129 | register struct tab *p; |
| 130 | { |
| 131 | |
| 132 | if(p->pid != 0) { |
| 133 | rmut(p); |
| 134 | kill(p->pid, SIGKILL); |
| 135 | } |
| 136 | p->pid = 0; |
| 137 | p->line[0] = 0; |
| 138 | } |
| 139 | |
| 140 | rline() |
| 141 | { |
| 142 | register c, i; |
| 143 | |
| 144 | c = get(); |
| 145 | if(c < 0) |
| 146 | return(0); |
| 147 | if(c == 0) |
| 148 | goto bad; |
| 149 | line.flag = c; |
| 150 | c = get(); |
| 151 | if(c <= 0) |
| 152 | goto bad; |
| 153 | line.comn = c; |
| 154 | for(i=0; i<8; i++) |
| 155 | line.line[i] = 0; |
| 156 | for(i=0; i<7; i++) { |
| 157 | c = get(); |
| 158 | if(c <= 0) |
| 159 | break; |
| 160 | line.line[i] = c; |
| 161 | } |
| 162 | while(c > 0) |
| 163 | c = get(); |
| 164 | maktty(line.line); |
| 165 | if(access(tty, 06) < 0) |
| 166 | goto bad; |
| 167 | return(1); |
| 168 | |
| 169 | bad: |
| 170 | line.flag = '0'; |
| 171 | return(1); |
| 172 | } |
| 173 | |
| 174 | maktty(lin) |
| 175 | char *lin; |
| 176 | { |
| 177 | register i, j; |
| 178 | |
| 179 | for(i=0; dev[i]; i++) |
| 180 | tty[i] = dev[i]; |
| 181 | for(j=0; lin[j]; j++) { |
| 182 | tty[i] = lin[j]; |
| 183 | i++; |
| 184 | } |
| 185 | tty[i] = 0; |
| 186 | } |
| 187 | |
| 188 | get() |
| 189 | { |
| 190 | char b; |
| 191 | |
| 192 | if(read(fi, &b, 1) != 1) |
| 193 | return(-1); |
| 194 | if(b == '\n') |
| 195 | return(0); |
| 196 | return(b); |
| 197 | } |
| 198 | |
| 199 | merge() |
| 200 | { |
| 201 | register struct tab *p, *q; |
| 202 | register i; |
| 203 | |
| 204 | close(creat(utmp, 0644)); |
| 205 | signal(SIGINT, merge); |
| 206 | fi = open(ifile, 0); |
| 207 | if(fi < 0) |
| 208 | return; |
| 209 | q = &itab[0]; |
| 210 | while(rline()) { |
| 211 | if(line.flag == '0') |
| 212 | continue; |
| 213 | for(ALL) { |
| 214 | if(p->line[0] != 0) |
| 215 | for(i=0; i<8; i++) |
| 216 | if(p->line[i] != line.line[i]) |
| 217 | goto contin; |
| 218 | if(p >= q) { |
| 219 | i = p->pid; |
| 220 | p->pid = q->pid; |
| 221 | q->pid = i; |
| 222 | for(i=0; i<8; i++) |
| 223 | p->line[i] = q->line[i]; |
| 224 | p->comn = q->comn; |
| 225 | for(i=0; i<8; i++) |
| 226 | q->line[i] = line.line[i]; |
| 227 | q->comn = line.comn; |
| 228 | q++; |
| 229 | } |
| 230 | break; |
| 231 | contin: |
| 232 | ; |
| 233 | } |
| 234 | } |
| 235 | close(fi); |
| 236 | for(; q < &itab[TABSIZ]; q++) |
| 237 | term(q); |
| 238 | for(ALL) |
| 239 | if(p->line[0] != 0 && p->pid == 0) |
| 240 | dfork(p); |
| 241 | } |
| 242 | |
| 243 | dfork(p) |
| 244 | struct tab *p; |
| 245 | { |
| 246 | register pid; |
| 247 | |
| 248 | pid = fork(); |
| 249 | if(pid == 0) { |
| 250 | signal(SIGHUP, SIG_DFL); |
| 251 | signal(SIGINT, SIG_DFL); |
| 252 | maktty(p->line); |
| 253 | chown(tty, 0, 0); |
| 254 | chmod(tty, 0622); |
| 255 | open(tty, 2); |
| 256 | dup(0); |
| 257 | dup(0); |
| 258 | tty[0] = p->comn; |
| 259 | tty[1] = 0; |
| 260 | execl(getty, minus, tty, (char *)0); |
| 261 | exit(0); |
| 262 | } |
| 263 | p->pid = pid; |
| 264 | } |
| 265 | |
| 266 | rmut(p) |
| 267 | register struct tab *p; |
| 268 | { |
| 269 | register i, f; |
| 270 | |
| 271 | f = open(utmp, 2); |
| 272 | if(f >= 0) { |
| 273 | while(read(f, (char *)&wtmp, sizeof(wtmp)) == sizeof(wtmp)) { |
| 274 | for(i=0; i<8; i++) |
| 275 | if(wtmp.ut_line[i] != p->line[i]) |
| 276 | goto contin; |
| 277 | lseek(f, (long)-sizeof(wtmp), 1); |
| 278 | for(i=0; i<8; i++) |
| 279 | wtmp.ut_name[i] = 0; |
| 280 | time(&wtmp.ut_time); |
| 281 | write(f, (char *)&wtmp, sizeof(wtmp)); |
| 282 | contin:; |
| 283 | } |
| 284 | close(f); |
| 285 | } |
| 286 | f = open(wtmpf, 1); |
| 287 | if (f >= 0) { |
| 288 | for(i=0; i<8; i++) { |
| 289 | wtmp.ut_name[i] = 0; |
| 290 | wtmp.ut_line[i] = p->line[i]; |
| 291 | } |
| 292 | time(&wtmp.ut_time); |
| 293 | lseek(f, (long)0, 2); |
| 294 | write(f, (char *)&wtmp, sizeof(wtmp)); |
| 295 | close(f); |
| 296 | } |
| 297 | } |
| 298 | |
| 299 | reset() |
| 300 | { |
| 301 | longjmp(sjbuf, 1); |
| 302 | } |