Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!julius.cs.uiuc.edu!ux1.cso.uiuc.edu!midway!oddjob!malagoli From: malagoli@oddjob.uchicago.edu (Andrea Malagoli) Newsgroups: comp.sys.sgi Subject: lockscreen (with fewer bugs, I hope) Message-ID: <1990Oct4.225555.23860@midway.uchicago.edu> Date: 4 Oct 90 22:55:55 GMT Sender: news@midway.uchicago.edu (News Administrator) Reply-To: malagoli@oddjob.UChicago.EDU () Distribution: usa Organization: U of Chicago - Astronomy & Astrophysics Lines: 411 I post here a version of lockscreen that has been modified according to the many useful suggestions I got from readers of this newsgroup. Thanks to all of them ! The program is still not 100% safe, but it works fine on several Irises. A problem seemed to occurr when an Iris is running yellow pages. I thought that getpwuid() and getuid() would work even on a yp client, but apparently this is not the case. Does anyone know the solution to this problem ? Thanks in advance. Andrea Malagoli Astronomy Department University of Chicago e-mail: malagoli@mhd4.uchicago.edu -------------------------------cut here-------------------------------- /* * L O C K S C R E E N * * lockscreen utiliy for the SGI machines * * lockscreen allows a user to lock the access to the monitor * without logging out. This is useful when one needs to go * out of the office and does not want to leave the machine * accessible to anybody. * * After calling lockscreen, the screen gets blank and a bouncing * ball appears on a black background. To unlock, press the * RIGHT MOUSE BUTTON. When the prompt asking for the password * appears, just enter the correct password. * * Just compile with * cc -o lockscreen lockscreen.c -lgl_s -lc_s * * This code has been written borrowing some routines available * in 4Dgifts/examples/grafix. * * WRITTEN BY: Andrea Malagoli * Astronomy Department * University of Chicago * malagoli@mhd.uchicago.edu * * DATE: 15 June 1990 * * LAST MODIFIED: 4 October 1990. * Added capability of diplaying * text at the center of the screen * when the ball is bouncing. You * need to compile with the -DTXT * flag. The current text is * "CLASSIFIED PROCESSING", but one * can change it to whatever. * * - Added an open to /dev/console * to prevent remote users to run * lockscreen and seize the screen. * - Added possibility for root to * unlock the screen, by simply typing * the super-user password in. * To prevent this, compile with the * -DNOROOT flag. * ( Modifications suggested by * Dan Watts of Ki Research, Inc.). * * (KNOWN) BUGS: A remote user can still seize the console terminal * by modifing the source code, or by writing a similar * application that does not open /dev/console. I am not * sure how to go around this. * */ #include #include #include #include #include #include int fcons; /* Console file descriptor */ /* These lines contain the color and the text of the line * printed when the bouncing ball is running. You can change * both the color and the text here. */ #ifdef TXT int colortxt = GREEN; static char myline[]="CLASSIFIED PROCESSING"; #endif TXT Icoord maxxval; /* width of prompt window ( in screen coords) */ char filename[20]; /* array to store standard input for the prompt */ struct passwd mypwd; /* User information from /etc/passwd */ static char fprompt[80] = "Enter Password for "; char *prompt, *prompt1; int curpos, prevpos; /* cursor current and previous positions */ long xvelocity = 0, yvelocity = 0; /* initial ball velocity */ int iter=1; #define XMIN 0 #define XMAX XMAXSCREEN #define YMIN 0 #define YMAX YMAXSCREEN /* setup for the prompt box */ Screencoord mask1, mask2, mask3, mask4; /* full window */ main() { Device dev; short val; int check_pwd(); if( (fcons = open("/dev/console", O_RDWR)) == -1 ) { printf("Cannot start lockscreen\n"); exit(1); } init(); hyde_cursor(); mypwd = *getpwuid( getuid() ); /* Get User ID and * encrypted password */ prompt1 = strcat(fprompt,mypwd.pw_name); /* Set the prompt */ prompt = strcat(prompt1,": "); xvelocity = (long int) (rand(0.6)/32767.*150); yvelocity = (long int) (rand(0.3)/32767.*150); /* process events forever */ while(TRUE) { drawball(); while( qtest() ){ dev=qread(&val); switch(dev) { case RIGHTMOUSE: if(val) { singlebuffer(); gconfig(); color( BLUE ); clear(); mktxtport(); if(check_pwd(filename) == 1){ endit(); break; } else { doublebuffer(); gconfig(); break; } } break; default: break; } } } } endit() { close( fcons ); gexit(); exit(0); } init() { /* do all the basic graphics setup */ ginit(); doublebuffer(); gconfig(); maxxval = 590; /* prompt window's width in pixels */ qdevice(RIGHTMOUSE); } #ifdef TXT write_txt() { color(colortxt); cmov2i( (XMAX-strwidth(myline))/2, YMAX/2); charstr(myline); } #endif TXT /* screen positionings of prompt box */ #define FILEX 340 #define FILEY 500 #define FILEYHI (30+FILEY) /* 30 pixels hi */ #define TEXTX (FILEX+5) #define TEXTY (FILEY+10) /* Clear prompt, move to start of prompt box, and output requested prompt */ clearprompt(prmpt) char *prmpt; { color(WHITE); rectfi(FILEX, FILEY, (Screencoord)(FILEX+maxxval-6), FILEYHI); color(BLACK); linewidth(2); recti(FILEX+2, FILEY+2, FILEX+maxxval-6, FILEYHI-3); linewidth(1); cmov2i(TEXTX, TEXTY); charstr(prmpt); } mktxtport() /* get name of file */ { int curstrlen; short c; char *cc = "a"; char *str; Device dev; long maxwidth; size_t maxlen = sizeof(filename); char *prmpt; prmpt = prompt; maxwidth = (XMAXSCREEN-11) - (FILEX + strwidth(prmpt)); /* display prompt */ curstrlen = 0; clearprompt(prmpt); curpos = TEXTX + strwidth(prmpt) + 2; prevpos = curpos; draw_bar(); qdevice(KEYBD); /* read until carriage return or linefeed */ while(dev = qread(&c)) { if(dev != KEYBD) continue; /* don't care */ switch(c) { case '\027': /* ctrl-W sets back to start of prompt */ curstrlen = 0; clearprompt(prmpt); prevpos = curpos; curpos = TEXTX + strwidth(prmpt) + 2; draw_bar(); break; case '\n': case '\r': goto done; case '\b': if(curstrlen) { *cc = filename[--curstrlen]; filename[curstrlen] = '\0'; clearprompt(prmpt); /* display rightmost portion */ for(str=filename; *str && strwidth(str) > maxwidth; str++); prevpos = curpos; curpos = curpos - strwidth(cc); draw_bar(); } break; default: if( curstrlen > 20 ) break; str = &filename[curstrlen]; filename[curstrlen++] = c; filename[curstrlen] = '\0'; *cc = c; prevpos = curpos; curpos = curpos + strwidth(cc); draw_bar(); break; } } done: unqdevice(KEYBD); } int check_pwd(pww) char *pww; { struct passwd rootpwd; /* Root information from /etc/passwd */ char salt[3]; mypwd = *getpwuid( getuid() ); /* Get User ID and * encrypted password */ strncpy(salt, mypwd.pw_passwd, 2); if( strcmp(mypwd.pw_passwd,crypt(pww,salt)) == 0 ){ return 1; #ifdef NOROOT } else return 0; #else NOROOT } else { rootpwd = *getpwnam("root"); /* Get root encrypted password */ strncpy(salt, rootpwd.pw_passwd, 2); if( strcmp(rootpwd.pw_passwd,crypt(pww,salt)) == 0 ) { return 1; /* We can also enter root password */ } else return 0; } #endif NOROOT } drawball() { static xpos = 500,ypos = 500; long radius = 20; if( iter >= 200 ) { xvelocity = (long int) (rand(0.6)/32767.*60); yvelocity = (long int) (rand(0.3)/32767.*60); iter = 0; } iter++; color(BLACK); clear(); #ifdef TXT write_txt(); #endif TXT xpos += xvelocity; ypos += yvelocity; if (xpos > XMAX - radius || xpos < XMIN + radius) { xpos -= xvelocity; xvelocity = -xvelocity; } if (ypos > YMAX - radius || ypos < YMIN + radius) { ypos -= yvelocity; yvelocity = -yvelocity; } color(YELLOW); circfi(xpos, ypos, radius); swapbuffers(); } hyde_cursor() { short index; static short blank[16][16]={{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}}; curstype(C16X1); drawmode(CURSORDRAW); defcursor(1, blank); setcursor(1, 0, 0); drawmode(NORMALDRAW); } draw_bar() { static int ydown = (FILEY + 5); static int yup = (FILEYHI - 7); int vert[2]; linewidth(1); if( prevpos != curpos ){ color( WHITE ); bgnline(); vert[0] = prevpos; vert[1] = ydown; v2i(vert); vert[0] = prevpos; vert[1] = yup; v2i(vert); endline(); color( BLACK ); bgnline(); vert[0] = curpos; vert[1] = ydown; v2i(vert); vert[0] = curpos; vert[1] = yup; v2i(vert); endline(); } else { color( BLACK ); bgnline(); vert[0] = curpos; vert[1] = ydown; v2i(vert); vert[0] = curpos; vert[1] = yup; v2i(vert); endline(); } }