sys/src/cmd/aux/cdsh.c

   1 /*
   2  * The `cd' shell.
   3  * Just has cd and lc.
   4  */
   5
   6 #include <u.h>
   7 #include <libc.h>
   8 #include <bio.h>
   9
  10 char *pwd;
  11 char *root = "/";
  12
  13 void
  14 usage(void)
  15 {
  16         fprint(2, "usage: cdsh [-r root]\n");
  17         exits("usage");
  18 }
  19
  20 int
  21 system(char *cmd)
  22 {
  23         int pid;
  24         if((pid = fork()) < 0)
  25                 return -1;
  26
  27         if(pid == 0) {
  28                 dup(2, 1);
  29                 execl("/bin/rc", "rc", "-c", cmd, nil);
  30                 exits("exec");
  31         }
  32         waitpid();
  33         return 0;
  34 }
  35
  36 int
  37 cd(char *s)
  38 {
  39         char *newpwd;
  40         int l;
  41
  42         if(s[0] == '/') {
  43                 cleanname(s);
  44                 newpwd = strdup(s);
  45         } else {
  46                 l = strlen(pwd)+1+strlen(s)+1+50;       /* 50 = crud for unicode mistakes */
  47                 newpwd = malloc(l);
  48                 snprint(newpwd, l, "%s/%s", pwd, s);
  49                 cleanname(newpwd);
  50                 assert(newpwd[0] == '/');
  51         }
  52
  53         if(chdir(root) < 0 || (newpwd[1] != '\0' && chdir(newpwd+1) < 0)) {
  54                 chdir(root);
  55                 chdir(pwd+1);
  56                 free(newpwd);
  57                 return -1;
  58         } else {
  59                 free(pwd);
  60                 pwd = newpwd;
  61                 return 0;
  62         }
  63 }
  64
  65 void
  66 main(int argc, char **argv)
  67 {
  68         char *p;
  69         Biobuf bin;
  70         char *f[2];
  71         int nf;
  72
  73         ARGBEGIN{
  74         case 'r':
  75                 root = ARGF();
  76                 if(root == nil)
  77                         usage();
  78                 if(root[0] != '/') {
  79                         fprint(2, "root must be rooted\n");
  80                         exits("root");
  81                 }
  82                 break;
  83         default:
  84                 usage();
  85         }ARGEND;
  86
  87         if(argc != 0)
  88                 usage();
  89
  90         cleanname(root);
  91         if(cd("/") < 0) {
  92                 fprint(2, "cannot cd %s: %r\n", root);
  93                 exits("root");
  94         }
  95
  96         Binit(&bin, 0, OREAD);
  97         while(fprint(2, "%s%% ", pwd), (p = Brdline(&bin, '\n'))) {
  98                 p[Blinelen(&bin)-1] = '\0';
  99                 nf = tokenize(p, f, nelem(f));
 100                 if(nf < 1)
 101                         continue;
 102                 if(strcmp(f[0], "exit") == 0)
 103                         break;
 104                 if(strcmp(f[0], "lc") == 0) {
 105                         if(nf == 1) {
 106                                 if(system("/bin/lc") < 0)
 107                                         fprint(2, "lc: %r\n");
 108                         } else if(nf == 2) {
 109                                 if(strpbrk(p, "'`{}^@$#&()|\\;><"))
 110                                         fprint(2, "no shell characters allowed\n");
 111                                 else {
 112                                         p = f[1];
 113                                         *--p = ' ';
 114                                         *--p = 'c';
 115                                         *--p = 'l';
 116                                         if(system(p) < 0)
 117                                                 fprint(2, "lc: %r\n");
 118                                 }
 119                         }
 120                         continue;
 121                 }
 122                 if(strcmp(f[0], "cd") == 0) {
 123                         if(nf < 2)
 124                                 fprint(2, "usage: cd dir\n");
 125                         else if(cd(f[1]) < 0)
 126                                 fprint(2, "cd: %r\n");
 127                         continue;
 128                 }
 129                 fprint(2, "commands are cd, lc, and exit\n");
 130         }
 131
 132         print("%s\n", pwd);
 133 }