Handle the case when /sys/class/tty/ entries are not symlinks.

For example:

$ uname -a
Linux RT-N66U 2.6.22.19 #1 Thu Feb 12 20:33:36 CST 2015 mips GNU/Linux

$ ls -lF /sys/class/tty/
drwxr-xr-x    2 foo  root             0 May 18 18:12 ttyACM0/

$ ls -lF /sys/class/tty/ttyACM0/
-r--r--r--    1 foo  root          4096 May 18 18:12 dev
lrwxrwxrwx    1 foo  root             0 May 18 18:12 device -> ../../../devices/pci0000:00/0000:00:04.1/usb1/1-1/1-1.1/1-1.1:1.0/
lrwxrwxrwx    1 foo  root             0 May 18 18:12 subsystem -> ../../../class/tty/
-rw-r--r--    1 foo  root          4096 May 18 18:12 uevent

diff --git a/linux.c b/linux.c
index d2cf1294646f1a7a7b1e4fd6fca1f5dcc11aa2bc..f9b2ec69c888ed96ded15ad177126116ff97af20 100644 (file)
--- a/linux.c
+++ b/linux.c
@@ -36,11 +36,16 @@ SP_PRIV enum sp_return get_port_details(struct sp_port *port)
        char *ptr, *dev = port->name + 5;
        FILE *file;
        int i, count;
+       struct stat statbuf;
 
        if (strncmp(port->name, "/dev/", 5))
                RETURN_ERROR(SP_ERR_ARG, "Device name not recognized");
 
        snprintf(file_name, sizeof(file_name), "/sys/class/tty/%s", dev);
+       if (lstat(file_name, &statbuf) == -1)
+               RETURN_ERROR(SP_ERR_ARG, "Device not found");
+       if (!S_ISLNK(statbuf.st_mode))
+               snprintf(file_name, sizeof(file_name), "/sys/class/tty/%s/device", dev);
        count = readlink(file_name, file_name, sizeof(file_name));
        if (count <= 0 || count >= (int)(sizeof(file_name) - 1))
                RETURN_ERROR(SP_ERR_ARG, "Device not found");
@@ -176,10 +181,11 @@ SP_PRIV enum sp_return list_ports(struct sp_port ***list)
        struct serial_struct serial_info;
        int ioctl_result;
 #endif
-       char buf[sizeof(entry.d_name) + 16];
+       char buf[sizeof(entry.d_name) + 23];
        int len, fd;
        DIR *dir;
        int ret = SP_OK;
+       struct stat statbuf;
 
        DEBUG("Enumerating tty devices");
        if (!(dir = opendir("/sys/class/tty")))
@@ -188,6 +194,10 @@ SP_PRIV enum sp_return list_ports(struct sp_port ***list)
        DEBUG("Iterating over results");
        while (!readdir_r(dir, &entry, &result) && result) {
                snprintf(buf, sizeof(buf), "/sys/class/tty/%s", entry.d_name);
+               if (lstat(buf, &statbuf) == -1)
+                       continue;
+               if (!S_ISLNK(statbuf.st_mode))
+                       snprintf(buf, sizeof(buf), "/sys/class/tty/%s/device", entry.d_name);
                len = readlink(buf, target, sizeof(target));
                if (len <= 0 || len >= (int)(sizeof(target) - 1))
                        continue;