| 1 | /* |
| 2 | * Print working (current) directory |
| 3 | */ |
| 4 | #include <stdio.h> |
| 5 | #include <sys/param.h> |
| 6 | #include <sys/stat.h> |
| 7 | #include <sys/dir.h> |
| 8 | |
| 9 | char dot[] = "."; |
| 10 | char dotdot[] = ".."; |
| 11 | char name[512]; |
| 12 | int file; |
| 13 | int off = -1; |
| 14 | struct stat d, dd; |
| 15 | struct direct dir; |
| 16 | |
| 17 | main() |
| 18 | { |
| 19 | int rdev, rino; |
| 20 | |
| 21 | stat("/", &d); |
| 22 | rdev = d.st_dev; |
| 23 | rino = d.st_ino; |
| 24 | for (;;) { |
| 25 | stat(dot, &d); |
| 26 | if (d.st_ino==rino && d.st_dev==rdev) |
| 27 | prname(); |
| 28 | if ((file = open(dotdot,0)) < 0) { |
| 29 | fprintf(stderr,"pwd: cannot open ..\n"); |
| 30 | exit(1); |
| 31 | } |
| 32 | fstat(file, &dd); |
| 33 | chdir(dotdot); |
| 34 | if(d.st_dev == dd.st_dev) { |
| 35 | if(d.st_ino == dd.st_ino) |
| 36 | prname(); |
| 37 | do |
| 38 | if (read(file, (char *)&dir, sizeof(dir)) < sizeof(dir)) { |
| 39 | fprintf(stderr,"read error in ..\n"); |
| 40 | exit(1); |
| 41 | } |
| 42 | while (dir.d_ino != d.st_ino); |
| 43 | } |
| 44 | else do { |
| 45 | if(read(file, (char *)&dir, sizeof(dir)) < sizeof(dir)) { |
| 46 | fprintf(stderr,"read error in ..\n"); |
| 47 | exit(1); |
| 48 | } |
| 49 | stat(dir.d_name, &dd); |
| 50 | } while(dd.st_ino != d.st_ino || dd.st_dev != d.st_dev); |
| 51 | close(file); |
| 52 | cat(); |
| 53 | } |
| 54 | } |
| 55 | |
| 56 | prname() |
| 57 | { |
| 58 | write(1, "/", 1); |
| 59 | if (off<0) |
| 60 | off = 0; |
| 61 | name[off] = '\n'; |
| 62 | write(1, name, off+1); |
| 63 | exit(0); |
| 64 | } |
| 65 | |
| 66 | cat() |
| 67 | { |
| 68 | register i, j; |
| 69 | |
| 70 | i = -1; |
| 71 | while (dir.d_name[++i] != 0); |
| 72 | if ((off+i+2) > 511) |
| 73 | prname(); |
| 74 | for(j=off+1; j>=0; --j) |
| 75 | name[j+i+1] = name[j]; |
| 76 | off=i+off+1; |
| 77 | name[i] = '/'; |
| 78 | for(--i; i>=0; --i) |
| 79 | name[i] = dir.d_name[i]; |
| 80 | } |