Research V6 development

Work on file usr/source/s2/su.c

Co-Authored-By: Ken Thompson <ken@research.uucp>
Synthesized-from: v6

diff --git a/usr/source/s2/su.c b/usr/source/s2/su.c
new file mode 100644 (file)
index 0000000..679502c
--- /dev/null
+++ b/usr/source/s2/su.c
@@ -0,0 +1,46 @@
+/* su -- become super-user */
+
+char   password[100];
+char   pwbuf[100];
+int    ttybuf[3];
+main()
+{
+       register char *p, *q;
+       extern fin;
+
+       if(getpw(0, pwbuf))
+               goto badpw;
+       (&fin)[1] = 0;
+       p = pwbuf;
+       while(*p != ':')
+               if(*p++ == '\0')
+                       goto badpw;
+       if(*++p == ':')
+               goto ok;
+       gtty(0, ttybuf);
+       ttybuf[2] =& ~010;
+       stty(0, ttybuf);
+       printf("password: ");
+       q = password;
+       while((*q = getchar()) != '\n')
+               if(*q++ == '\0')
+                       return;
+       *q = '\0';
+       ttybuf[2] =| 010;
+       stty(0, ttybuf);
+       printf("\n");
+       q = crypt(password);
+       while(*q++ == *p++);
+       if(*--q == '\0' && *--p == ':')
+               goto ok;
+       goto error;
+
+badpw:
+       printf("bad password file\n");
+ok:
+       setuid(0);
+       execl("/bin/sh", "-", 0);
+       printf("cannot execute shell\n");
+error:
+       printf("sorry\n");
+}