am edeed28b: am 4a280e3d: Merge "Don\'t use control requests to read device serial numbers."
* commit 'edeed28bd397f863686ba3e5bb7479f881efc657':
Don't use control requests to read device serial numbers.
diff --git a/fastboot/usb_linux.c b/fastboot/usb_linux.c
index b7a9ca3..9153c8d 100644
--- a/fastboot/usb_linux.c
+++ b/fastboot/usb_linux.c
@@ -75,10 +75,18 @@
unsigned char ep_out;
};
+/* True if name isn't a valid name for a USB device in /sys/bus/usb/devices.
+ * Device names are made up of numbers, dots, and dashes, e.g., '7-1.5'.
+ * We reject interfaces (e.g., '7-1.5:1.0') and host controllers (e.g. 'usb1').
+ * The name must also start with a digit, to disallow '.' and '..'
+ */
static inline int badname(const char *name)
{
- while(*name) {
- if(!isdigit(*name++)) return 1;
+ if (!isdigit(*name))
+ return 1;
+ while(*++name) {
+ if(!isdigit(*name) && *name != '.' && *name != '-')
+ return 1;
}
return 0;
}
@@ -95,7 +103,8 @@
return 0;
}
-static int filter_usb_device(int fd, char *ptr, int len, int writable,
+static int filter_usb_device(int fd, char* sysfs_name,
+ char *ptr, int len, int writable,
ifc_match_func callback,
int *ept_in_id, int *ept_out_id, int *ifc_id)
{
@@ -131,69 +140,35 @@
info.dev_protocol = dev->bDeviceProtocol;
info.writable = writable;
- // read device serial number (if there is one)
- info.serial_number[0] = 0;
- if (dev->iSerialNumber) {
- struct usbdevfs_ctrltransfer ctrl;
- // Keep it short enough because some bootloaders are borked if the URB len is > 255
- // 128 is too big by 1.
- __u16 buffer[127];
+ snprintf(info.device_path, sizeof(info.device_path), "usb:%s", sysfs_name);
- memset(buffer, 0, sizeof(buffer));
-
- ctrl.bRequestType = USB_DIR_IN|USB_TYPE_STANDARD|USB_RECIP_DEVICE;
- ctrl.bRequest = USB_REQ_GET_DESCRIPTOR;
- ctrl.wValue = (USB_DT_STRING << 8) | dev->iSerialNumber;
- //language ID (en-us) for serial number string
- ctrl.wIndex = 0x0409;
- ctrl.wLength = sizeof(buffer);
- ctrl.data = buffer;
- ctrl.timeout = 50;
-
- result = ioctl(fd, USBDEVFS_CONTROL, &ctrl);
- if (result > 0) {
- int i;
- // skip first word, and copy the rest to the serial string, changing shorts to bytes.
- result /= 2;
- for (i = 1; i < result; i++)
- info.serial_number[i - 1] = buffer[i];
- info.serial_number[i - 1] = 0;
- }
- }
-
- /* We need to get a path that represents a particular port on a particular
- * hub. We are passed an fd that was obtained by opening an entry under
- * /dev/bus/usb. Unfortunately, the names of those entries change each
- * time devices are plugged and unplugged. So how to get a repeatable
- * path? udevadm provided the inspiration. We can get the major and
- * minor of the device file, read the symlink that can be found here:
- * /sys/dev/char/<major>:<minor>
- * and then use the last element of that path. As a concrete example, I
- * have an Android device at /dev/bus/usb/001/027 so working with bash:
- * $ ls -l /dev/bus/usb/001/027
- * crw-rw-r-- 1 root plugdev 189, 26 Apr 9 11:03 /dev/bus/usb/001/027
- * $ ls -l /sys/dev/char/189:26
- * lrwxrwxrwx 1 root root 0 Apr 9 11:03 /sys/dev/char/189:26 ->
- * ../../devices/pci0000:00/0000:00:1a.7/usb1/1-4/1-4.2/1-4.2.3
- * So our device_path would be 1-4.2.3 which says my device is connected
- * to port 3 of a hub on port 2 of a hub on port 4 of bus 1 (per
- * http://www.linux-usb.org/FAQ.html).
+ /* Read device serial number (if there is one).
+ * We read the serial number from sysfs, since it's faster and more
+ * reliable than issuing a control pipe read, and also won't
+ * cause problems for devices which don't like getting descriptor
+ * requests while they're in the middle of flashing.
*/
- info.device_path[0] = '\0';
- result = fstat(fd, &st);
- if (!result && S_ISCHR(st.st_mode)) {
- char cdev[128];
- char link[256];
- char *slash;
- ssize_t link_len;
- snprintf(cdev, sizeof(cdev), "/sys/dev/char/%d:%d",
- major(st.st_rdev), minor(st.st_rdev));
- link_len = readlink(cdev, link, sizeof(link) - 1);
- if (link_len > 0) {
- link[link_len] = '\0';
- slash = strrchr(link, '/');
- if (slash)
- snprintf(info.device_path, sizeof(info.device_path), "usb:%s", slash+1);
+ info.serial_number[0] = '\0';
+ if (dev->iSerialNumber) {
+ char path[80];
+ int fd;
+
+ snprintf(path, sizeof(path),
+ "/sys/bus/usb/devices/%s/serial", sysfs_name);
+ path[sizeof(path) - 1] = '\0';
+
+ fd = open(path, O_RDONLY);
+ if (fd >= 0) {
+ int chars_read = read(fd, info.serial_number,
+ sizeof(info.serial_number) - 1);
+ close(fd);
+
+ if (chars_read <= 0)
+ info.serial_number[0] = '\0';
+ else if (info.serial_number[chars_read - 1] == '\n') {
+ // strip trailing newline
+ info.serial_number[chars_read - 1] = '\0';
+ }
}
}
@@ -241,14 +216,73 @@
return -1;
}
+static int read_sysfs_string(const char *sysfs_name, const char *sysfs_node,
+ char* buf, int bufsize)
+{
+ char path[80];
+ int fd, n;
+
+ snprintf(path, sizeof(path),
+ "/sys/bus/usb/devices/%s/%s", sysfs_name, sysfs_node);
+ path[sizeof(path) - 1] = '\0';
+
+ fd = open(path, O_RDONLY);
+ if (fd < 0)
+ return -1;
+
+ n = read(fd, buf, bufsize - 1);
+ close(fd);
+
+ if (n < 0)
+ return -1;
+
+ buf[n] = '\0';
+
+ return n;
+}
+
+static int read_sysfs_number(const char *sysfs_name, const char *sysfs_node)
+{
+ char buf[16];
+ int value;
+
+ if (read_sysfs_string(sysfs_name, sysfs_node, buf, sizeof(buf)) < 0)
+ return -1;
+
+ if (sscanf(buf, "%d", &value) != 1)
+ return -1;
+
+ return value;
+}
+
+/* Given the name of a USB device in sysfs, get the name for the same
+ * device in devfs. Returns 0 for success, -1 for failure.
+ */
+static int convert_to_devfs_name(const char* sysfs_name,
+ char* devname, int devname_size)
+{
+ int busnum, devnum;
+
+ busnum = read_sysfs_number(sysfs_name, "busnum");
+ if (busnum < 0)
+ return -1;
+
+ devnum = read_sysfs_number(sysfs_name, "devnum");
+ if (devnum < 0)
+ return -1;
+
+ snprintf(devname, devname_size, "/dev/bus/usb/%03d/%03d", busnum, devnum);
+ return 0;
+}
+
static usb_handle *find_usb_device(const char *base, ifc_match_func callback)
{
usb_handle *usb = 0;
- char busname[64], devname[64];
+ char devname[64];
char desc[1024];
int n, in, out, ifc;
- DIR *busdir, *devdir;
+ DIR *busdir;
struct dirent *de;
int fd;
int writable;
@@ -259,15 +293,7 @@
while((de = readdir(busdir)) && (usb == 0)) {
if(badname(de->d_name)) continue;
- sprintf(busname, "%s/%s", base, de->d_name);
- devdir = opendir(busname);
- if(devdir == 0) continue;
-
-// DBG("[ scanning %s ]\n", busname);
- while((de = readdir(devdir)) && (usb == 0)) {
-
- if(badname(de->d_name)) continue;
- sprintf(devname, "%s/%s", busname, de->d_name);
+ if(!convert_to_devfs_name(de->d_name, devname, sizeof(devname))) {
// DBG("[ scanning %s ]\n", devname);
writable = 1;
@@ -282,7 +308,7 @@
n = read(fd, desc, sizeof(desc));
- if(filter_usb_device(fd, desc, n, writable, callback,
+ if(filter_usb_device(fd, de->d_name, desc, n, writable, callback,
&in, &out, &ifc) == 0) {
usb = calloc(1, sizeof(usb_handle));
strcpy(usb->fname, devname);
@@ -301,7 +327,6 @@
close(fd);
}
}
- closedir(devdir);
}
closedir(busdir);
@@ -431,5 +456,5 @@
usb_handle *usb_open(ifc_match_func callback)
{
- return find_usb_device("/dev/bus/usb", callback);
+ return find_usb_device("/sys/bus/usb/devices", callback);
}