//================================================================= // // usb_chmod.c // // A utility to manipulate /proc/bus/usb access rights // //========================================================================== //####ECOSGPLCOPYRIGHTBEGIN#### // ------------------------------------------- // This file is part of eCos, the Embedded Configurable Operating System. // Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc. // // eCos is free software; you can redistribute it and/or modify it under // the terms of the GNU General Public License as published by the Free // Software Foundation; either version 2 or (at your option) any later version. // // eCos is distributed in the hope that it will be useful, but WITHOUT ANY // WARRANTY; without even the implied warranty of MERCHANTABILITY or // FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License // for more details. // // You should have received a copy of the GNU General Public License along // with eCos; if not, write to the Free Software Foundation, Inc., // 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. // // As a special exception, if other files instantiate templates or use macros // or inline functions from this file, or you compile this file and link it // with other works to produce a work based on this file, this file does not // by itself cause the resulting work to be covered by the GNU General Public // License. However the source code for this file must still be made available // in accordance with section (3) of the GNU General Public License. // // This exception does not invalidate any other reasons why a work based on // this file might be covered by the GNU General Public License. // // Alternative licenses for eCos may be arranged by contacting Red Hat, Inc. // at http://sources.redhat.com/ecos/ecos-license/ // ------------------------------------------- //####ECOSGPLCOPYRIGHTEND#### //========================================================================== //#####DESCRIPTIONBEGIN#### // // The Linux kernel allows raw access to USB devices via /proc/bus/usb. // However, such access requires root privileges: this makes perfect // sense for typical USB devices, but gets in the way of eCos USB // testing. This utility runs suid and can be used to change the access // rights to a specific and validated USB device. // // Author(s): bartv // Date: 2001-07-18 //####DESCRIPTIONEND#### //========================================================================== #include #include #include #include #include #include // Note: this code is duplicated in usbhost.c. Any changes here // should be propagated. For now the routine is too small to warrant // a separate source file. #define USB_ROOT "/proc/bus/usb/" #define PRODUCT_STRING "Red Hat eCos USB test" static int usb_scan_devices(int* bus, int* dev) { FILE* devs_file = fopen(USB_ROOT "devices", "r"); int current_bus = -1; int current_dev = -1; int ch; if (NULL == devs_file) { fprintf(stderr, "Error: unable to access " USB_ROOT "devices\n"); return 0; } ch = getc(devs_file); while (EOF != ch) { if ('T' == ch) { if (2 !=fscanf(devs_file, ": Bus=%d %*[^D\n]Dev#=%d", ¤t_bus, ¤t_dev)) { current_bus = -1; current_dev = -1; } } else if ('S' == ch) { int start = 0, end = 0; if (EOF != fscanf(devs_file, ": Product=%n" PRODUCT_STRING "%n", &start, &end)) { if (start < end) { *bus = current_bus; *dev = current_dev; break; } } } // Move to the end of the current line. do { ch = getc(devs_file); } while ((EOF != ch) && ('\n' != ch)); if (EOF != ch) { ch = getc(devs_file); } } fclose(devs_file); if ((-1 != *bus) && (-1 != *dev)) { return 1; } fprintf(stderr, "Error: failed to find a USB device \"" PRODUCT_STRING "\"\n"); return 0; } int main(int argc, char** argv) { int bus, dev; int actual_bus, actual_dev; char devname[_POSIX_PATH_MAX]; long strtol_tmp1; char* strtol_tmp2; if (3 != argc) { fprintf(stderr, "usb_chmod: wrong number of arguments\n"); fprintf(stderr, " : usage, usb_chmod \n"); exit(EXIT_FAILURE); } if (('\0' == argv[1][0]) || ('\0' == argv[2][0])) { fprintf(stderr, "usb_chmod: invalid arguments\n"); exit(EXIT_FAILURE); } strtol_tmp1 = strtol(argv[1], &strtol_tmp2, 10); if ('\0' != *strtol_tmp2) { fprintf(stderr, "usbchmod: invalid first argument, not a number\n"); exit(EXIT_FAILURE); } if (strtol_tmp1 > INT_MAX) { fprintf(stderr, "usbchmod: invalid first argument, number too large\n"); exit(EXIT_FAILURE); } bus = (int) strtol_tmp1; strtol_tmp1 = strtol(argv[2], &strtol_tmp2, 10); if ('\0' != *strtol_tmp2) { fprintf(stderr, "usbchmod: invalid second argument, not a number\n"); exit(EXIT_FAILURE); } if (strtol_tmp1 > INT_MAX) { fprintf(stderr, "usbchmod: invalid second argument, number too large\n"); exit(EXIT_FAILURE); } dev = (int) strtol_tmp1; if (!usb_scan_devices(&actual_bus, &actual_dev)) { fprintf(stderr, "usb_chmod: failed to find eCos USB test application\n"); exit(EXIT_FAILURE); } if ((bus != actual_bus) || (dev != actual_dev)) { fprintf(stderr, "usbchmod: mismatch between specified and actual USB identifiers.\n"); fprintf(stderr, " : eCos test application is at %03d/%03d, not %03d/%03d\n", actual_bus, actual_dev, bus, dev); exit(EXIT_FAILURE); } if (_POSIX_PATH_MAX == snprintf(devname, _POSIX_PATH_MAX, "/proc/bus/usb/" "%03d/%03d", actual_bus, actual_dev)) { fprintf(stderr, "usbchmod: internal error, buffer overflow\n"); exit(EXIT_FAILURE); } if (0 != chmod(devname, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH)) { int old_errno = errno; fprintf(stderr, "usbchmod: failed to modify access rights on %s\n", devname); if ((old_errno >= 0) && (old_errno < sys_nerr)) { fprintf(stderr, " : %s\n", sys_errlist[old_errno]); } exit(EXIT_FAILURE); } return EXIT_SUCCESS; }