linux.c

   1 /*
   2  * This file is part of the libserialport project.
   3  *
   4  * Copyright (C) 2013 Martin Ling <martin-libserialport@earth.li>
   5  * Copyright (C) 2014 Aurelien Jacobs <aurel@gnuage.org>
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU Lesser General Public License as
   9  * published by the Free Software Foundation, either version 3 of the
  10  * License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public License
  18  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include <config.h>
  22 #include "libserialport.h"
  23 #include "libserialport_internal.h"
  24
  25 /*
  26  * The 'e' modifier for O_CLOEXEC is glibc >= 2.7 only, hence not
  27  * portable, so provide an own wrapper for this functionality.
  28  */
  29 static FILE *fopen_cloexec_rdonly(const char *pathname)
  30 {
  31         int fd;
  32         if ((fd = open(pathname, O_RDONLY | O_CLOEXEC)) < 0)
  33                 return NULL;
  34         return fdopen(fd, "r");
  35 }
  36
  37 SP_PRIV enum sp_return get_port_details(struct sp_port *port)
  38 {
  39         /*
  40          * Description limited to 127 char, anything longer
  41          * would not be user friendly anyway.
  42          */
  43         char description[128];
  44         int bus, address;
  45         unsigned int vid, pid;
  46         char manufacturer[128], product[128], serial[128];
  47         char baddr[32];
  48         const char dir_name[] = "/sys/class/tty/%s/device/%s%s";
  49         char sub_dir[32] = "", link_name[PATH_MAX], file_name[PATH_MAX];
  50         char *ptr, *dev = port->name + 5;
  51         FILE *file;
  52         int i, count;
  53         struct stat statbuf;
  54
  55         if (strncmp(port->name, "/dev/", 5))
  56                 RETURN_ERROR(SP_ERR_ARG, "Device name not recognized");
  57
  58         snprintf(link_name, sizeof(link_name), "/sys/class/tty/%s", dev);
  59         if (lstat(link_name, &statbuf) == -1)
  60                 RETURN_ERROR(SP_ERR_ARG, "Device not found");
  61         if (!S_ISLNK(statbuf.st_mode))
  62                 snprintf(link_name, sizeof(link_name), "/sys/class/tty/%s/device", dev);
  63         count = readlink(link_name, file_name, sizeof(file_name));
  64         if (count <= 0 || count >= (int)(sizeof(file_name) - 1))
  65                 RETURN_ERROR(SP_ERR_ARG, "Device not found");
  66         file_name[count] = 0;
  67         if (strstr(file_name, "bluetooth"))
  68                 port->transport = SP_TRANSPORT_BLUETOOTH;
  69         else if (strstr(file_name, "usb"))
  70                 port->transport = SP_TRANSPORT_USB;
  71
  72         if (port->transport == SP_TRANSPORT_USB) {
  73                 for (i = 0; i < 5; i++) {
  74                         strcat(sub_dir, "../");
  75
  76                         snprintf(file_name, sizeof(file_name), dir_name, dev, sub_dir, "busnum");
  77                         if (!(file = fopen_cloexec_rdonly(file_name)))
  78                                 continue;
  79                         count = fscanf(file, "%d", &bus);
  80                         fclose(file);
  81                         if (count != 1)
  82                                 continue;
  83
  84                         snprintf(file_name, sizeof(file_name), dir_name, dev, sub_dir, "devnum");
  85                         if (!(file = fopen_cloexec_rdonly(file_name)))
  86                                 continue;
  87                         count = fscanf(file, "%d", &address);
  88                         fclose(file);
  89                         if (count != 1)
  90                                 continue;
  91
  92                         snprintf(file_name, sizeof(file_name), dir_name, dev, sub_dir, "idVendor");
  93                         if (!(file = fopen_cloexec_rdonly(file_name)))
  94                                 continue;
  95                         count = fscanf(file, "%4x", &vid);
  96                         fclose(file);
  97                         if (count != 1)
  98                                 continue;
  99
 100                         snprintf(file_name, sizeof(file_name), dir_name, dev, sub_dir, "idProduct");
 101                         if (!(file = fopen_cloexec_rdonly(file_name)))
 102                                 continue;
 103                         count = fscanf(file, "%4x", &pid);
 104                         fclose(file);
 105                         if (count != 1)
 106                                 continue;
 107
 108                         port->usb_bus = bus;
 109                         port->usb_address = address;
 110                         port->usb_vid = vid;
 111                         port->usb_pid = pid;
 112
 113                         snprintf(file_name, sizeof(file_name), dir_name, dev, sub_dir, "product");
 114                         if ((file = fopen_cloexec_rdonly(file_name))) {
 115                                 if ((ptr = fgets(description, sizeof(description), file))) {
 116                                         ptr = description + strlen(description) - 1;
 117                                         if (ptr >= description && *ptr == '\n')
 118                                                 *ptr = 0;
 119                                         port->description = strdup(description);
 120                                 }
 121                                 fclose(file);
 122                         }
 123                         if (!file || !ptr)
 124                                 port->description = strdup(dev);
 125
 126                         snprintf(file_name, sizeof(file_name), dir_name, dev, sub_dir, "manufacturer");
 127                         if ((file = fopen_cloexec_rdonly(file_name))) {
 128                                 if ((ptr = fgets(manufacturer, sizeof(manufacturer), file))) {
 129                                         ptr = manufacturer + strlen(manufacturer) - 1;
 130                                         if (ptr >= manufacturer && *ptr == '\n')
 131                                                 *ptr = 0;
 132                                         port->usb_manufacturer = strdup(manufacturer);
 133                                 }
 134                                 fclose(file);
 135                         }
 136
 137                         snprintf(file_name, sizeof(file_name), dir_name, dev, sub_dir, "product");
 138                         if ((file = fopen_cloexec_rdonly(file_name))) {
 139                                 if ((ptr = fgets(product, sizeof(product), file))) {
 140                                         ptr = product + strlen(product) - 1;
 141                                         if (ptr >= product && *ptr == '\n')
 142                                                 *ptr = 0;
 143                                         port->usb_product = strdup(product);
 144                                 }
 145                                 fclose(file);
 146                         }
 147
 148                         snprintf(file_name, sizeof(file_name), dir_name, dev, sub_dir, "serial");
 149                         if ((file = fopen_cloexec_rdonly(file_name))) {
 150                                 if ((ptr = fgets(serial, sizeof(serial), file))) {
 151                                         ptr = serial + strlen(serial) - 1;
 152                                         if (ptr >= serial && *ptr == '\n')
 153                                                 *ptr = 0;
 154                                         port->usb_serial = strdup(serial);
 155                                 }
 156                                 fclose(file);
 157                         }
 158
 159                         /* If present, add serial to description for better identification. */
 160                         if (port->usb_serial && strlen(port->usb_serial)) {
 161                                 snprintf(description, sizeof(description),
 162                                         "%s - %s", port->description, port->usb_serial);
 163                                 if (port->description)
 164                                         free(port->description);
 165                                 port->description = strdup(description);
 166                         }
 167
 168                         break;
 169                 }
 170         } else {
 171                 port->description = strdup(dev);
 172
 173                 if (port->transport == SP_TRANSPORT_BLUETOOTH) {
 174                         snprintf(file_name, sizeof(file_name), dir_name, dev, "", "address");
 175                         if ((file = fopen_cloexec_rdonly(file_name))) {
 176                                 if ((ptr = fgets(baddr, sizeof(baddr), file))) {
 177                                         ptr = baddr + strlen(baddr) - 1;
 178                                         if (ptr >= baddr && *ptr == '\n')
 179                                                 *ptr = 0;
 180                                         port->bluetooth_address = strdup(baddr);
 181                                 }
 182                                 fclose(file);
 183                         }
 184                 }
 185         }
 186
 187         RETURN_OK();
 188 }
 189
 190 SP_PRIV enum sp_return list_ports(struct sp_port ***list)
 191 {
 192         char name[PATH_MAX], target[PATH_MAX];
 193         struct dirent *entry;
 194 #ifdef HAVE_STRUCT_SERIAL_STRUCT
 195         struct serial_struct serial_info;
 196         int ioctl_result;
 197 #endif
 198         char buf[sizeof(entry->d_name) + 23];
 199         int len, fd;
 200         DIR *dir;
 201         int ret = SP_OK;
 202         struct stat statbuf;
 203
 204         DEBUG("Enumerating tty devices");
 205         if (!(dir = opendir("/sys/class/tty")))
 206                 RETURN_FAIL("Could not open /sys/class/tty");
 207
 208         DEBUG("Iterating over results");
 209         while ((entry = readdir(dir))) {
 210                 snprintf(buf, sizeof(buf), "/sys/class/tty/%s", entry->d_name);
 211                 if (lstat(buf, &statbuf) == -1)
 212                         continue;
 213                 if (!S_ISLNK(statbuf.st_mode))
 214                         snprintf(buf, sizeof(buf), "/sys/class/tty/%s/device", entry->d_name);
 215                 len = readlink(buf, target, sizeof(target));
 216                 if (len <= 0 || len >= (int)(sizeof(target) - 1))
 217                         continue;
 218                 target[len] = 0;
 219                 if (strstr(target, "virtual"))
 220                         continue;
 221                 snprintf(name, sizeof(name), "/dev/%s", entry->d_name);
 222                 DEBUG_FMT("Found device %s", name);
 223                 if (strstr(target, "serial8250")) {
 224                         /*
 225                          * The serial8250 driver has a hardcoded number of ports.
 226                          * The only way to tell which actually exist on a given system
 227                          * is to try to open them and make an ioctl call.
 228                          */
 229                         DEBUG("serial8250 device, attempting to open");
 230                         if ((fd = open(name, O_RDWR | O_NONBLOCK | O_NOCTTY | O_CLOEXEC)) < 0) {
 231                                 DEBUG("Open failed, skipping");
 232                                 continue;
 233                         }
 234 #ifdef HAVE_STRUCT_SERIAL_STRUCT
 235                         ioctl_result = ioctl(fd, TIOCGSERIAL, &serial_info);
 236 #endif
 237                         close(fd);
 238 #ifdef HAVE_STRUCT_SERIAL_STRUCT
 239                         if (ioctl_result != 0) {
 240                                 DEBUG("ioctl failed, skipping");
 241                                 continue;
 242                         }
 243                         if (serial_info.type == PORT_UNKNOWN) {
 244                                 DEBUG("Port type is unknown, skipping");
 245                                 continue;
 246                         }
 247 #endif
 248                 }
 249                 DEBUG_FMT("Found port %s", name);
 250                 *list = list_append(*list, name);
 251                 if (!*list) {
 252                         SET_ERROR(ret, SP_ERR_MEM, "List append failed");
 253                         break;
 254                 }
 255         }
 256         closedir(dir);
 257
 258         return ret;
 259 }