[Qemu-devel] [PATCH] Add USB sys file-system support (v5)

[TJ <linux@tjworld.net>]

On Wed, 2008-09-17 at 15:31 -0500, Anthony Liguori wrote:

> Signed-off-by: TJ <linux@tjworld.net>
> >   
> 
> A valid Signed-off-by requires a full name, not just an abbreviation.

This is valid and full.

> usb_host_device_path please.  Also, the explicit initialization to 0 is 
> unnecessary.  This should probably be a const char * too?

If it were 'const' it would cause a compiler warning with
strcpy(usb_host_device_path, devpath) in usb_host_scan().

> 
> >      if (fd < 0) {
> >          perror(buf);
> >          goto fail;
> >      }
> > +    printf("husb: opened %s\n", buf);
> >   
> 
> Please don't add unconditional printfs.

This was changed to dprintf() as described in the previous precis but
the patch-generation accidentally came from older code.

> This indenting is wrong.  QEMU uses 4-space tabs.

Hmmm... something certainly went wrong. The source has 4-space tabs...
aha! Forgot to do a "git-add" after "git-reset --soft" when modifying
white-space (an interim text editor decided to silently translate spaces
to tabs), before "git-commit -C", thus ending up with the working
directory copy more recent than the commit, which was the source of
"git-format-patch -1".

The attached patch *should* be tab-free.

> 
> >  static int usb_host_scan(void *opaque, USBScanFunc *func)
> >  {
> > -    FILE *f;
> > -    char line[1024];
> > -    char buf[1024];
> > -    int bus_num, addr, speed, device_count, class_id, product_id, vendor_id;
> > -    int ret;
> > -    char product_name[512];
> > +	FILE *f = 0;
> > +	DIR *dir = 0;
> > +	int ret = 0;
> > +	char *devices = "/devices";
> > +	char *trying = "husb: trying to open %s%s\n";
> > +	char *failed = "husb: could not open %s%s\n";
> > +	char devpath[PATH_MAX];
> > +
> > +	// only check the host once
> > +	if (!USBfs) {
> > +		// test for dev file-system access in /proc/
> > +		term_printf(trying, USBPROCBUS_PATH, devices);
> > +		f = fopen(USBPROCBUS_PATH "/devices", "r");
> > +		if (!f) {
> > +			term_printf(failed, USBPROCBUS_PATH, devices);
> > +			// maybe it has been moved to the /dev/ base
> > +			term_printf(trying, USBDEVBUS_PATH, devices);
> > +			f = fopen(USBDEVBUS_PATH "/devices", "r");
> > +			if (!f) {
> > +				term_printf(failed, USBDEVBUS_PATH, devices);
> > +				// test for newer sys file-system access
> > +				term_printf(trying, USBSYSBUS_PATH, devices);
> > +				dir = opendir(USBSYSBUS_PATH "/devices");
> > +				if (!dir) {
> > +					term_printf(failed, USBSYSBUS_PATH, devices);
> > +					goto the_end;
> > +				}
> > +				else { // devices found in /dev/bus/usb/ (yes - not a mistake!)
> > +					strcpy(devpath, USBDEVBUS_PATH);
> > +					USBfs = USB_FS_SYS;
> > +				}
> > +				if (dir) closedir(dir);
> > +			}
> > +			else { // devices found in /dev/bus/usb/
> > +				strcpy(devpath, USBDEVBUS_PATH);
> > +				USBfs = USB_FS_DEV;
> > +			}
> > +		}
> > +		else { // devices found in /proc/bus/usb/
> > +			strcpy(devpath, USBPROCBUS_PATH);
> > +			USBfs = USB_FS_PROC;
> > +		}
> > +		if (f) fclose(f);
> >   
> 
> The term_printfs are also way too verbose.

Demoted to dprintf().

--------------------------------------
This patch adds support for host USB devices discovered via:

/sys/bus/usb/devices/* and opened from /dev/bus/usb/*/*
/dev/bus/usb/devices and opened from /dev/bus/usb/*/*

in addition to the existing discovery via:

/proc/bus/usb/devices and opened from /proc/bus/usb/*/*

Signed-off-by: TJ <linux@tjworld.net>
---
--- a/usb-linux.c   2008-09-17 22:39:38.000000000 +0100
+++ b/usb-linux.c   2008-09-17 23:42:32.000000000 +0100
@@ -7,6 +7,10 @@
  *      Support for host device auto connect & disconnect
  *      Major rewrite to support fully async operation
  *
+ * Copyright 2008 TJ <linux@tjworld.net>
+ *      Added flexible support for /dev/bus/usb /sys/bus/usb/devices in addition
+ *      to the legacy /proc/bus/usb USB device discovery and handling
+ *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
@@ -72,9 +76,20 @@
 #define dprintf(...)
 #endif
 
-#define USBDEVFS_PATH "/proc/bus/usb"
+#define USBPROCBUS_PATH "/proc/bus/usb"
 #define PRODUCT_NAME_SZ 32
 #define MAX_ENDPOINTS 16
+#define USBDEVBUS_PATH "/dev/bus/usb"
+#define USBSYSBUS_PATH "/sys/bus/usb"
+
+static char *usb_host_device_path;
+
+#define USB_FS_NONE 0
+#define USB_FS_PROC 1
+#define USB_FS_DEV 2
+#define USB_FS_SYS 3
+
+static int usb_fs_type = 0;
 
 /* endpoint association data */
 struct endp_data {
@@ -890,13 +905,18 @@
 
     printf("husb: open device %d.%d\n", bus_num, addr);
 
-    snprintf(buf, sizeof(buf), USBDEVFS_PATH "/%03d/%03d",
+    if (!usb_host_device_path) {
+        perror("husb: USB Host Device Path not set");
+        goto fail;
+    }
+    snprintf(buf, sizeof(buf), "%s/%03d/%03d", usb_host_device_path,
              bus_num, addr);
     fd = open(buf, O_RDWR | O_NONBLOCK);
     if (fd < 0) {
         perror(buf);
         goto fail;
     }
+    dprintf("husb: opened %s\n", buf);
 
     /* read the device description */
     dev->descr_len = read(fd, dev->descr, sizeof(dev->descr));
@@ -1038,80 +1058,275 @@
     return q - buf;
 }
 
-static int usb_host_scan(void *opaque, USBScanFunc *func)
+/*
+ Use /proc/bus/usb/devices or /dev/bus/usb/devices file to determine
+ host's USB devices. This is legacy support since many distributions
+ are moving to /sys/bus/usb
+*/
+static int usb_host_scan_dev(void *opaque, USBScanFunc *func)
 {
-    FILE *f;
+    FILE *f = 0;
     char line[1024];
     char buf[1024];
     int bus_num, addr, speed, device_count, class_id, product_id, vendor_id;
-    int ret;
     char product_name[512];
+    int ret = 0;
 
-    f = fopen(USBDEVFS_PATH "/devices", "r");
+    snprintf(line, sizeof(line), "%s/devices", usb_host_device_path);
+    f = fopen(line, "r");
     if (!f) {
-        term_printf("husb: could not open %s\n", USBDEVFS_PATH "/devices");
-        return 0;
+        perror("husb: cannot open devices file");
+        goto the_end;
     }
+
     device_count = 0;
     bus_num = addr = speed = class_id = product_id = vendor_id = 0;
-    ret = 0;
     for(;;) {
-        if (fgets(line, sizeof(line), f) == NULL)
-            break;
-        if (strlen(line) > 0)
-            line[strlen(line) - 1] = '\0';
-        if (line[0] == 'T' && line[1] == ':') {
-            if (device_count && (vendor_id || product_id)) {
-                /* New device.  Add the previously discovered device.  */
-                ret = func(opaque, bus_num, addr, class_id, vendor_id,
-                           product_id, product_name, speed);
-                if (ret)
-                    goto the_end;
-            }
-            if (get_tag_value(buf, sizeof(buf), line, "Bus=", " ") < 0)
-                goto fail;
-            bus_num = atoi(buf);
-            if (get_tag_value(buf, sizeof(buf), line, "Dev#=", " ") < 0)
-                goto fail;
-            addr = atoi(buf);
-            if (get_tag_value(buf, sizeof(buf), line, "Spd=", " ") < 0)
-                goto fail;
-            if (!strcmp(buf, "480"))
-                speed = USB_SPEED_HIGH;
-            else if (!strcmp(buf, "1.5"))
-                speed = USB_SPEED_LOW;
-            else
-                speed = USB_SPEED_FULL;
-            product_name[0] = '\0';
-            class_id = 0xff;
-            device_count++;
-            product_id = 0;
-            vendor_id = 0;
-        } else if (line[0] == 'P' && line[1] == ':') {
-            if (get_tag_value(buf, sizeof(buf), line, "Vendor=", " ") < 0)
-                goto fail;
-            vendor_id = strtoul(buf, NULL, 16);
-            if (get_tag_value(buf, sizeof(buf), line, "ProdID=", " ") < 0)
-                goto fail;
-            product_id = strtoul(buf, NULL, 16);
-        } else if (line[0] == 'S' && line[1] == ':') {
-            if (get_tag_value(buf, sizeof(buf), line, "Product=", "") < 0)
-                goto fail;
-            pstrcpy(product_name, sizeof(product_name), buf);
-        } else if (line[0] == 'D' && line[1] == ':') {
-            if (get_tag_value(buf, sizeof(buf), line, "Cls=", " (") < 0)
-                goto fail;
-            class_id = strtoul(buf, NULL, 16);
-        }
-    fail: ;
+        if (fgets(line, sizeof(line), f) == NULL)
+            break;
+        if (strlen(line) > 0)
+            line[strlen(line) - 1] = '\0';
+        if (line[0] == 'T' && line[1] == ':') {
+            if (device_count && (vendor_id || product_id)) {
+                /* New device.  Add the previously discovered device.  */
+                ret = func(opaque, bus_num, addr, class_id, vendor_id,
+                            product_id, product_name, speed);
+                if (ret)
+                    goto the_end;
+            }
+            if (get_tag_value(buf, sizeof(buf), line, "Bus=", " ") < 0)
+                goto fail;
+
+            bus_num = atoi(buf);
+            if (get_tag_value(buf, sizeof(buf), line, "Dev#=", " ") < 0)
+                goto fail;
+
+            addr = atoi(buf);
+            if (get_tag_value(buf, sizeof(buf), line, "Spd=", " ") < 0)
+                goto fail;
+
+            if (!strcmp(buf, "480"))
+                speed = USB_SPEED_HIGH;
+            else if (!strcmp(buf, "1.5"))
+                speed = USB_SPEED_LOW;
+            else
+                speed = USB_SPEED_FULL;
+            product_name[0] = '\0';
+            class_id = 0xff;
+            device_count++;
+            product_id = 0;
+            vendor_id = 0;
+        }
+        else if (line[0] == 'P' && line[1] == ':') {
+            if (get_tag_value(buf, sizeof(buf), line, "Vendor=", " ") < 0)
+                goto fail;
+
+            vendor_id = strtoul(buf, NULL, 16);
+            if (get_tag_value(buf, sizeof(buf), line, "ProdID=", " ") < 0)
+                goto fail;
+
+            product_id = strtoul(buf, NULL, 16);
+        }
+        else if (line[0] == 'S' && line[1] == ':') {
+            if (get_tag_value(buf, sizeof(buf), line, "Product=", "") < 0)
+                goto fail;
+
+            pstrcpy(product_name, sizeof(product_name), buf);
+        }
+        else if (line[0] == 'D' && line[1] == ':') {
+            if (get_tag_value(buf, sizeof(buf), line, "Cls=", " (") < 0)
+                goto fail;
+
+            class_id = strtoul(buf, NULL, 16);
+        }
+ fail: ;
     }
     if (device_count && (vendor_id || product_id)) {
-        /* Add the last device.  */
-        ret = func(opaque, bus_num, addr, class_id, vendor_id,
-                   product_id, product_name, speed);
+        /* Add the last device.  */
+        ret = func(opaque, bus_num, addr, class_id, vendor_id,
+                    product_id, product_name, speed);
+    }
+ the_end:
+    if (f) fclose(f);
+    return ret;
+}
+
+/*
+ Use /sys/bus/usb/devices/ directory to determine host's USB devices.
+
+ This code is taken from Robert Schiele's original patches posted to the
+ Novell bug-tracker https://bugzilla.novell.com/show_bug.cgi?id=241950
+*/
+static int usb_host_scan_sys(void *opaque, USBScanFunc *func)
+{
+    FILE *f;
+    DIR *dir = 0;
+    char line[1024];
+    int bus_num, addr, speed, class_id, product_id, vendor_id;
+    int ret = 0;
+    char product_name[512];
+    struct dirent* de;
+
+    dir = opendir(USBSYSBUS_PATH "/devices");
+    if (!dir) {
+        perror("husb: cannot open devices directory");
+        goto the_end;
+    }
+
+    while ((de = readdir(dir))) {
+        if (de->d_name[0] != '.' && ! strchr(de->d_name, ':')) {
+            char filename[PATH_MAX];
+            char* tmpstr = de->d_name;
+            if (!strncmp(de->d_name, "usb", 3))
+                tmpstr += 3;
+
+            bus_num = atoi(tmpstr);
+            snprintf(filename, PATH_MAX, USBSYSBUS_PATH "/devices/%s/devnum", de->d_name);
+            f = fopen(filename, "r");
+            if (!f) {
+                term_printf("Could not open %s\n", filename);
+                goto the_end;
+            }
+            fgets(line, sizeof(line), f);
+            fclose(f);
+            addr = atoi(line);
+            snprintf(filename, PATH_MAX, USBSYSBUS_PATH "/devices/%s/bDeviceClass", de->d_name);
+            f = fopen(filename, "r");
+            if (!f) {
+                term_printf("Could not open %s\n", filename);
+                goto the_end;
+            }
+            fgets(line, sizeof(line), f);
+            fclose(f);
+            class_id = strtoul(line, NULL, 16);
+            snprintf(filename, PATH_MAX, USBSYSBUS_PATH "/devices/%s/idVendor", de->d_name);
+            f = fopen(filename, "r");
+            if (!f) {
+                term_printf("Could not open %s\n", filename);
+                goto the_end;
+            }
+            fgets(line, sizeof(line), f);
+            fclose(f);
+            vendor_id = strtoul(line, NULL, 16);
+            snprintf(filename, PATH_MAX, USBSYSBUS_PATH "/devices/%s/idProduct", de->d_name);
+            f = fopen(filename, "r");
+            if (!f) {
+                term_printf("Could not open %s\n", filename);
+                goto the_end;
+            }
+            fgets(line, sizeof(line), f);
+            fclose(f);
+            product_id = strtoul(line, NULL, 16);
+            snprintf(filename, PATH_MAX, USBSYSBUS_PATH "/devices/%s/product", de->d_name);
+            f = fopen(filename, "r");
+            if (f) {
+                fgets(line, sizeof(line), f);
+                fclose(f);
+                if (strlen(line) > 0)
+                    line[strlen(line) - 1] = '\0';
+
+                pstrcpy(product_name, sizeof(product_name), line);
+            } else
+                *product_name = 0;
+
+            snprintf(filename, PATH_MAX, USBSYSBUS_PATH "/devices/%s/speed", de->d_name);
+            f = fopen(filename, "r");
+            if (!f) {
+                term_printf("Could not open %s\n", filename);
+                goto the_end;
+            }
+            fgets(line, sizeof(line), f);
+            fclose(f);
+            if (!strcmp(line, "480\n"))
+                speed = USB_SPEED_HIGH;
+            else if (!strcmp(line, "1.5\n"))
+                speed = USB_SPEED_LOW;
+            else
+                speed = USB_SPEED_FULL;
+
+            ret = func(opaque, bus_num, addr, class_id, vendor_id,
+                        product_id, product_name, speed);
+            if (ret)
+                goto the_end;
+        }
+    }
+ the_end:
+    if (dir) closedir(dir);
+    return ret;
+}
+
+/*
+ Determine how to access the host's USB devices and call the specific
+ support function.
+ */
+static int usb_host_scan(void *opaque, USBScanFunc *func)
+{
+    FILE *f = 0;
+    DIR *dir = 0;
+    int ret = 0;
+    const char *devices = "/devices";
+    const char *trying = "husb: trying to open %s%s\n";
+    const char *failed = "husb: could not open %s%s\n";
+    char devpath[PATH_MAX];
+
+    // only check the host once
+    if (!usb_fs_type) {
+        // test for dev file-system access in /proc/
+        dprintf(trying, USBPROCBUS_PATH, devices);
+        f = fopen(USBPROCBUS_PATH "/devices", "r");
+        if (!f) {
+            dprintf(failed, USBPROCBUS_PATH, devices);
+            // maybe it has been moved to the /dev/ base
+            dprintf(trying, USBDEVBUS_PATH, devices);
+            f = fopen(USBDEVBUS_PATH "/devices", "r");
+            if (!f) {
+                dprintf(failed, USBDEVBUS_PATH, devices);
+                // test for newer sys file-system access
+                dprintf(trying, USBSYSBUS_PATH, devices);
+                dir = opendir(USBSYSBUS_PATH "/devices");
+                if (!dir) {
+                    dprintf(failed, USBSYSBUS_PATH, devices);
+                    goto the_end;
+                }
+                else { // devices found in /dev/bus/usb/ (yes - not a mistake!)
+                    strcpy(devpath, USBDEVBUS_PATH);
+                    usb_fs_type = USB_FS_SYS;
+                }
+                if (dir) closedir(dir);
+            }
+            else { // devices found in /dev/bus/usb/
+                strcpy(devpath, USBDEVBUS_PATH);
+                usb_fs_type = USB_FS_DEV;
+            }
+        }
+        else { // devices found in /proc/bus/usb/
+            strcpy(devpath, USBPROCBUS_PATH);
+            usb_fs_type = USB_FS_PROC;
+        }
+        if (f) fclose(f);
+
+        // the module setting (used later for opening devices)
+        usb_host_device_path = qemu_mallocz(strlen(devpath)+1);
+        if (usb_host_device_path) {
+            strcpy(usb_host_device_path, devpath);
+            term_printf("husb: using %s\n", usb_host_device_path);
+        }
+        else { // out of memory?
+            perror("husb: unable to allocate memory for device path");
+            goto the_end;
+        }
+    }
+
+    switch (usb_fs_type) {
+        case USB_FS_PROC:
+        case USB_FS_DEV:
+            ret = usb_host_scan_dev(opaque, func);
+            break;
+        case USB_FS_SYS:
+            ret = usb_host_scan_sys(opaque, func);
+            break;
     }
  the_end:
-    fclose(f);
     return ret;
 }