udftools-pktcdvd.patch

   1 From: Peter Osterlund <petero2@telia.com>
   2 Subject: Re: [RFC][PATCH] Control pktcdvd with an auxiliary character device
   3 To: linux-kernel@vger.kernel.org
   4 Cc: Christoph Hellwig <hch@infradead.org>, Arnd Bergmann <arnd@arndb.de>,
   5         Jens Axboe <axboe@suse.de>, Andrew Morton <akpm@osdl.org>
   6 Date: Wed Jul 14 02:17:27 2004 +0200
   7
   8 Peter Osterlund <petero2@telia.com> writes:
   9
  10 > Peter Osterlund <petero2@telia.com> writes:
  11 >
  12 > > Christoph Hellwig <hch@infradead.org> writes:
  13 > >
  14 > > > On Sun, Jul 11, 2004 at 01:20:45AM +0200, Arnd Bergmann wrote:
  15 > > > > These are actually incorrect definitions since the ioctl argument is
  16 > > > > not a pointer to unsigned int but instead just an int. However, that's
  17 > > > > too late to fix without breaking the existing tools.
  18 > > >
  19 > > > The tools need to change anyway to get away from the broken behaviour to
  20 > > > issue in ioctl on the actual block device to bind it..
  21 > >
  22 > > OK, I'll create a patch that gets rid of the ioctl interface and uses
  23 > > an auxiliary character device instead to control device bindings.
  24 >
  25 > Here is a patch for 2.6.7-mm7 that does that. The driver creates a
  26 > misc character device and bind/unbind of the block devices are
  27 > controlled by ioctl commands on the char device.
  28 >
  29 > This patch needs corresponding changes in the pktsetup user space
  30 > program. I'll post a patch for pktsetup as a separate message.
  31
  32 And here is a patch for udftools-1.0.0b3 that updates the pktsetup
  33 program to make it able to use the character device for block device
  34 setup/teardown.
  35
  36 ---
  37
  38  udftools-1.0.0b3-petero/pktsetup/pktsetup.c |  245 +++++++++++++++++++++++++++-
  39  1 files changed, 238 insertions(+), 7 deletions(-)
  40
  41 diff -puN pktsetup/pktsetup.c~pktsetup-char-dev pktsetup/pktsetup.c
  42 --- udftools-1.0.0b3/pktsetup/pktsetup.c~pktsetup-char-dev      2004-07-12 19:57:51.000000000 +0200
  43 +++ udftools-1.0.0b3-petero/pktsetup/pktsetup.c 2004-07-14 00:34:02.471317888 +0200
  44 @@ -1,5 +1,6 @@
  45  /*
  46   * Copyright (c) 1999,2000     Jens Axboe <axboe@suse.de>
  47 + * Copyright (c) 2004          Peter Osterlund <petero2@telia.com>
  48   *
  49   *   This program is free software; you can redistribute it and/or modify
  50   *   it under the terms of the GNU General Public License as published by
  51 @@ -19,6 +20,7 @@
  52  #include <stdio.h>
  53  #include <fcntl.h>
  54  #include <sys/ioctl.h>
  55 +#include <sys/stat.h>
  56  #include <unistd.h>
  57  #include <getopt.h>
  58  #include <bits/types.h>
  59 @@ -33,8 +35,33 @@
  60  #define PACKET_SETUP_DEV       _IOW('X', 1, unsigned int)
  61  #define PACKET_TEARDOWN_DEV    _IOW('X', 2, unsigned int)
  62  #endif
  63 +#ifndef PACKET_CTRL_CMD
  64 +#define PACKET_CTRL_CMD                _IOWR('X', 1, struct pkt_ctrl_command)
  65 +#endif
  66 +
  67 +#define MAJOR(dev)      ((dev & 0xfff00) >> 8)
  68 +#define MINOR(dev)      ((dev & 0xff) | ((dev >> 12) & 0xfff00))
  69 +#define MKDEV(ma,mi)    ((mi & 0xff) | (ma << 8) | ((mi & ~0xff) << 12))
  70 +
  71 +#define MISC_MAJOR             10
  72 +#define CTL_DIR "/dev/pktcdvd"
  73 +#define CTL_DEV "control"
  74 +
  75 +#define PKT_CTRL_CMD_SETUP     0
  76 +#define PKT_CTRL_CMD_TEARDOWN  1
  77 +#define PKT_CTRL_CMD_STATUS    2
  78 +
  79 +struct pkt_ctrl_command {
  80 +       __u32 command;                          /* in: Setup, teardown, status */
  81 +       __u32 dev_index;                        /* in/out: Device index */
  82 +       __u32 dev;                              /* in/out: Device nr for cdrw device */
  83 +       __u32 pkt_dev;                          /* out: Device nr for packet device */
  84 +       __u32 num_devices;                      /* out: Largest device index + 1 */
  85 +       __u32 padding;
  86 +};
  87 +
  88
  89 -int init_cdrom(int fd)
  90 +static int init_cdrom(int fd)
  91  {
  92         if (ioctl(fd, CDROM_DRIVE_STATUS, CDSL_CURRENT) < 0) {
  93                 perror("drive not ready\n");
  94 @@ -54,7 +81,7 @@ int init_cdrom(int fd)
  95         return 0;
  96  }
  97
  98 -void setup_dev(char *pkt_device, char *device, int rem)
  99 +static void setup_dev(char *pkt_device, char *device, int rem)
 100  {
 101         int pkt_fd, dev_fd, cmd;
 102
 103 @@ -88,29 +115,233 @@ void setup_dev(char *pkt_device, char *d
 104         close(pkt_fd);
 105  }
 106
 107 -int usage(void)
 108 +static int usage(void)
 109  {
 110 -       printf("pktsetup /dev/pktcdvd0 /dev/cdrom\tsetup device\n");
 111 -       printf("pktsetup -d /dev/pktcdvd0\t\ttear down device\n");
 112 +       printf("For pktcdvd < 0.2.0:\n");
 113 +       printf("  pktsetup /dev/pktcdvd0 /dev/cdrom  setup device\n");
 114 +       printf("  pktsetup -d /dev/pktcdvd0          tear down device\n");
 115 +       printf("For pktcdvd >= 0.2.0:\n");
 116 +       printf("  pktsetup dev_name /dev/cdrom       setup device\n");
 117 +       printf("  pktsetup -d dev_name               tear down device\n");
 118 +       printf("  pktsetup -d major:minor            tear down device\n");
 119 +       printf("  pktsetup -s                        show device mappings\n");
 120         return 1;
 121  }
 122
 123 +/*
 124 + * Find the minor device number for the pktcdvd control device.
 125 + */
 126 +static int get_misc_minor(void)
 127 +{
 128 +       int minor;
 129 +       char name[64];
 130 +       FILE *f;
 131 +
 132 +       if ((f = fopen("/proc/misc", "r")) == NULL)
 133 +               return -1;
 134 +       while (fscanf(f, " %d %64s", &minor, name) == 2) {
 135 +               if (strcmp(name, "pktcdvd") == 0) {
 136 +                       fclose(f);
 137 +                       return minor;
 138 +               }
 139 +       }
 140 +       fclose(f);
 141 +       return -1;
 142 +}
 143 +
 144 +static const char *pkt_dev_name(const char *dev)
 145 +{
 146 +       static char buf[128];
 147 +       snprintf(buf, sizeof(buf), "%s/%s", CTL_DIR, dev);
 148 +       return buf;
 149 +}
 150 +
 151 +static void create_ctl_dev(void)
 152 +{
 153 +       int misc_minor;
 154 +       struct stat stat_buf;
 155 +       int dev;
 156 +
 157 +       if ((misc_minor = get_misc_minor()) < 0) {
 158 +               system("/sbin/modprobe pktcdvd");
 159 +               misc_minor = get_misc_minor();
 160 +       }
 161 +       if (misc_minor < 0) {
 162 +               fprintf(stderr, "Can't find pktcdvd character device\n");
 163 +               return;
 164 +       }
 165 +       dev = MKDEV(MISC_MAJOR, misc_minor);
 166 +
 167 +       if ((stat(pkt_dev_name(CTL_DEV), &stat_buf) >= 0) &&
 168 +           S_ISCHR(stat_buf.st_mode) && (stat_buf.st_rdev == dev))
 169 +               return;                     /* Already set up */
 170 +
 171 +       mkdir(CTL_DIR, 0755);
 172 +       unlink(pkt_dev_name(CTL_DEV));
 173 +       mknod(pkt_dev_name(CTL_DEV), S_IFCHR | 0644, dev);
 174 +}
 175 +
 176 +static int remove_stale_dev_node(int ctl_fd, char *devname)
 177 +{
 178 +       struct stat stat_buf;
 179 +       int i, dev;
 180 +       struct pkt_ctrl_command c;
 181 +
 182 +       if (stat(pkt_dev_name(devname), &stat_buf) < 0)
 183 +               return 0;
 184 +       if (!S_ISBLK(stat_buf.st_mode))
 185 +               return 1;
 186 +       dev = stat_buf.st_rdev;
 187 +       memset(&c, 0, sizeof(struct pkt_ctrl_command));
 188 +       for (i = 0; ; i++) {
 189 +               c.command = PKT_CTRL_CMD_STATUS;
 190 +               c.dev_index = i;
 191 +               if (ioctl(ctl_fd, PACKET_CTRL_CMD, &c) < 0) {
 192 +                       perror("ioctl");
 193 +                       return 1;
 194 +               }
 195 +               if (i >= c.num_devices)
 196 +                       break;
 197 +               if (c.pkt_dev == dev)
 198 +                       return 1;           /* busy */
 199 +       }
 200 +       unlink(pkt_dev_name(devname));
 201 +       return 0;
 202 +}
 203 +
 204 +static void setup_dev_chardev(char *pkt_device, char *device, int rem)
 205 +{
 206 +       struct pkt_ctrl_command c;
 207 +       struct stat stat_buf;
 208 +       int ctl_fd, dev_fd;
 209 +
 210 +       memset(&c, 0, sizeof(struct pkt_ctrl_command));
 211 +
 212 +       create_ctl_dev();
 213 +       if ((ctl_fd = open(pkt_dev_name(CTL_DEV), O_RDONLY)) < 0) {
 214 +               perror("ctl open");
 215 +               return;
 216 +       }
 217 +
 218 +       if (!rem) {
 219 +               if ((dev_fd = open(device, O_RDONLY | O_NONBLOCK)) == -1) {
 220 +                       perror("open cd-rom");
 221 +                       goto out_close;
 222 +               }
 223 +               if (init_cdrom(dev_fd)) {
 224 +                       close(dev_fd);
 225 +                       goto out_close;
 226 +               }
 227 +               close(dev_fd);
 228 +
 229 +               if (stat(device, &stat_buf) < 0) {
 230 +                       perror("stat cd-rom");
 231 +                       goto out_close;
 232 +               }
 233 +               if (!S_ISBLK(stat_buf.st_mode)) {
 234 +                       fprintf(stderr, "Not a block device\n");
 235 +                       goto out_close;
 236 +               }
 237 +               c.command = PKT_CTRL_CMD_SETUP;
 238 +               c.dev = stat_buf.st_rdev;
 239 +
 240 +               if (remove_stale_dev_node(ctl_fd, pkt_device) != 0) {
 241 +                       fprintf(stderr, "Device node '%s' already in use\n", pkt_device);
 242 +                       goto out_close;
 243 +               }
 244 +               if (ioctl(ctl_fd, PACKET_CTRL_CMD, &c) < 0) {
 245 +                       perror("ioctl");
 246 +                       goto out_close;
 247 +               }
 248 +               mknod(pkt_dev_name(pkt_device), S_IFBLK | 0640, c.pkt_dev);
 249 +       } else {
 250 +               int major, minor, remove_node;
 251 +
 252 +               if ((stat(pkt_dev_name(pkt_device), &stat_buf) >= 0) &&
 253 +                   S_ISBLK(stat_buf.st_mode)) {
 254 +                       major = MAJOR(stat_buf.st_rdev);
 255 +                       minor = MINOR(stat_buf.st_rdev);
 256 +                       remove_node = 1;
 257 +               } else if (sscanf(pkt_device, "%d:%d", &major, &minor) == 2) {
 258 +                       remove_node = 0;
 259 +               } else {
 260 +                       fprintf(stderr, "Can't find major/minor numbers\n");
 261 +                       goto out_close;
 262 +               }
 263 +
 264 +               c.command = PKT_CTRL_CMD_TEARDOWN;
 265 +               c.pkt_dev = MKDEV(major, minor);
 266 +               if (ioctl(ctl_fd, PACKET_CTRL_CMD, &c) < 0) {
 267 +                       perror("ioctl");
 268 +                       goto out_close;
 269 +               }
 270 +               if (remove_node)
 271 +                       unlink(pkt_dev_name(pkt_device));
 272 +       }
 273 +
 274 +out_close:
 275 +       close(ctl_fd);
 276 +}
 277 +
 278 +static void show_mappings(void)
 279 +{
 280 +       struct pkt_ctrl_command c;
 281 +       int ctl_fd, i;
 282 +
 283 +       memset(&c, 0, sizeof(struct pkt_ctrl_command));
 284 +
 285 +       create_ctl_dev();
 286 +       if ((ctl_fd = open(pkt_dev_name(CTL_DEV), O_RDONLY)) < 0) {
 287 +               perror("ctl open");
 288 +               return;
 289 +       }
 290 +
 291 +       for (i = 0; ; i++) {
 292 +               c.command = PKT_CTRL_CMD_STATUS;
 293 +               c.dev_index = i;
 294 +               if (ioctl(ctl_fd, PACKET_CTRL_CMD, &c) < 0) {
 295 +                       perror("ioctl");
 296 +                       goto out_close;
 297 +               }
 298 +               if (i >= c.num_devices)
 299 +                       break;
 300 +               if (c.dev) {
 301 +                       printf("%2d : %d:%d -> %d:%d\n",
 302 +                              i, MAJOR(c.pkt_dev), MINOR(c.pkt_dev),
 303 +                              MAJOR(c.dev), MINOR(c.dev));
 304 +               }
 305 +       }
 306 +
 307 +out_close:
 308 +       close(ctl_fd);
 309 +}
 310 +
 311  int main(int argc, char **argv)
 312  {
 313         int rem = 0, c;
 314 +       char *pkt_device;
 315 +       char *device;
 316
 317         if (argc == 1)
 318                 return usage();
 319
 320 -       while ((c = getopt(argc, argv, "d")) != EOF) {
 321 +       while ((c = getopt(argc, argv, "ds?")) != EOF) {
 322                 switch (c) {
 323                         case 'd':
 324                                 rem = 1;
 325                                 break;
 326 +                       case 's':
 327 +                               show_mappings();
 328 +                               return 0;
 329                         default:
 330                                 return usage();
 331                 }
 332         }
 333 -       setup_dev(argv[optind], argv[optind + 1], rem);
 334 +       pkt_device = argv[optind];
 335 +       device = argv[optind + 1];
 336 +       if (strchr(pkt_device, '/'))
 337 +               setup_dev(pkt_device, device, rem);
 338 +       else
 339 +               setup_dev_chardev(pkt_device, device, rem);
 340         return 0;
 341  }
 342 _
 343
 344 --
 345 Peter Osterlund - petero2@telia.com
 346 http://w1.894.telia.com/~u89404340