diff options
| -rw-r--r-- | libusb/os/linux_usbfs.c | 46 |
1 files changed, 43 insertions, 3 deletions
diff --git a/libusb/os/linux_usbfs.c b/libusb/os/linux_usbfs.c index 02d182d..2bdd510 100644 --- a/libusb/os/linux_usbfs.c +++ b/libusb/os/linux_usbfs.c @@ -212,13 +212,13 @@ static int check_usb_vfs(const char *dirname) static const char *find_usbfs_path(void) { - const char *path = "/dev/bus/usb"; + const char *path = "/proc/bus/usb"; const char *ret = NULL; if (check_usb_vfs(path)) { ret = path; } else { - path = "/proc/bus/usb"; + path = "/dev/bus/usb"; if (check_usb_vfs(path)) ret = path; } @@ -1211,6 +1211,38 @@ static int op_get_device_list(struct libusb_context *ctx, return usbfs_get_device_list(ctx, _discdevs); } +/* Returns the file descriptor of 'file_name', if it has been opened by the process, or -1 otherwise. */ +static int find_fd_by_name(char *file_name) +{ + struct dirent *fd_dirent; + DIR *proc_fd = opendir("/proc/self/fd"); + int ret = -1; + + while (fd_dirent = readdir(proc_fd)) + { + char link_file_name[1024]; + char fd_file_name[1024]; + + if (fd_dirent->d_type != DT_LNK) + { + continue; + } + + snprintf(link_file_name, 1024, "/proc/self/fd/%s", fd_dirent->d_name); + + memset(fd_file_name, 0, sizeof(fd_file_name)); + readlink(link_file_name, fd_file_name, sizeof(fd_file_name) - 1); + + if (!strcmp(fd_file_name, file_name)) + { + ret = atoi(fd_dirent->d_name); + } + } + + closedir(proc_fd); + + return ret; +} static int op_open(struct libusb_device_handle *handle) { struct linux_device_handle_priv *hpriv = _device_handle_priv(handle); @@ -1218,7 +1250,15 @@ static int op_open(struct libusb_device_handle *handle) _get_usbfs_path(handle->dev, filename); usbi_dbg("opening %s", filename); - hpriv->fd = open(filename, O_RDWR); + + hpriv->fd = find_fd_by_name(filename); + + /* Fallback to normal behavior */ + if (hpriv->fd == -1) + { + hpriv->fd = open(filename, O_RDWR); + } + if (hpriv->fd < 0) { if (errno == EACCES) { usbi_err(HANDLE_CTX(handle), "libusb couldn't open USB device %s: " |