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Merge "libusbhost: permits client polling on inotify wd"

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Mike Lockwood Gerrit Code Review
Mike Lockwood authored and Gerrit Code Review committed Dec 17, 2012
2 parents 13306d9 + dea46b6 commit dea9a93ddd66f8f40ae17d923e5ba0a4b109ac14
Showing with 118 additions and 65 deletions.
  1. +13 −0 include/usbhost/usbhost.h
  2. +105 −65 libusbhost/usbhost.c
@@ -72,6 +72,19 @@ struct usb_host_context *usb_host_init(void);
/* Call this to cleanup the USB host library. */
void usb_host_cleanup(struct usb_host_context *context);

/* Call this to get the inotify file descriptor. */
int usb_host_get_fd(struct usb_host_context *context);

/* Call this to initialize the usb host context. */
int usb_host_load(struct usb_host_context *context,
usb_device_added_cb added_cb,
usb_device_removed_cb removed_cb,
usb_discovery_done_cb discovery_done_cb,
void *client_data);

/* Call this to read and handle occuring usb event. */
int usb_host_read_event(struct usb_host_context *context);

/* Call this to monitor the USB bus for new and removed devices.
* This is intended to be called from a dedicated thread,
* as it will not return until one of the callbacks returns true.
@@ -33,6 +33,7 @@
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <stddef.h>

#include <sys/ioctl.h>
#include <sys/types.h>
@@ -50,16 +51,23 @@
#include "usbhost/usbhost.h"

#define DEV_DIR "/dev"
#define USB_FS_DIR "/dev/bus/usb"
#define USB_FS_ID_SCANNER "/dev/bus/usb/%d/%d"
#define USB_FS_ID_FORMAT "/dev/bus/usb/%03d/%03d"
#define USB_FS_DIR DEV_DIR "/bus/usb"
#define USB_FS_ID_SCANNER USB_FS_DIR "/%d/%d"
#define USB_FS_ID_FORMAT USB_FS_DIR "/%03d/%03d"

// From drivers/usb/core/devio.c
// I don't know why this isn't in a kernel header
#define MAX_USBFS_BUFFER_SIZE 16384

#define MAX_USBFS_WD_COUNT 10

struct usb_host_context {
int fd;
int fd;
usb_device_added_cb cb_added;
usb_device_removed_cb cb_removed;
void *data;
int wds[MAX_USBFS_WD_COUNT];
int wdd;
};

struct usb_device {
@@ -116,10 +124,10 @@ static int find_existing_devices(usb_device_added_cb added_cb,
while ((de = readdir(busdir)) != 0 && !done) {
if(badname(de->d_name)) continue;

snprintf(busname, sizeof(busname), "%s/%s", USB_FS_DIR, de->d_name);
snprintf(busname, sizeof(busname), USB_FS_DIR "/%s", de->d_name);
done = find_existing_devices_bus(busname, added_cb,
client_data);
}
} //end of busdir while
closedir(busdir);

return done;
@@ -137,7 +145,7 @@ static void watch_existing_subdirs(struct usb_host_context *context,

/* watch existing subdirectories of USB_FS_DIR */
for (i = 1; i < wd_count; i++) {
snprintf(path, sizeof(path), "%s/%03d", USB_FS_DIR, i);
snprintf(path, sizeof(path), USB_FS_DIR "/%03d", i);
ret = inotify_add_watch(context->fd, path, IN_CREATE | IN_DELETE);
if (ret >= 0)
wds[i] = ret;
@@ -166,93 +174,126 @@ void usb_host_cleanup(struct usb_host_context *context)
free(context);
}

void usb_host_run(struct usb_host_context *context,
int usb_host_get_fd(struct usb_host_context *context)
{
return context->fd;
} /* usb_host_get_fd() */

int usb_host_load(struct usb_host_context *context,
usb_device_added_cb added_cb,
usb_device_removed_cb removed_cb,
usb_discovery_done_cb discovery_done_cb,
void *client_data)
{
struct inotify_event* event;
char event_buf[512];
char path[100];
int i, ret, done = 0;
int wd, wdd, wds[10];
int wd_count = sizeof(wds) / sizeof(wds[0]);
int done = 0;
int i;

context->cb_added = added_cb;
context->cb_removed = removed_cb;
context->data = client_data;

D("Created device discovery thread\n");

/* watch for files added and deleted within USB_FS_DIR */
for (i = 0; i < wd_count; i++)
wds[i] = -1;
for (i = 0; i < MAX_USBFS_WD_COUNT; i++)
context->wds[i] = -1;

/* watch the root for new subdirectories */
wdd = inotify_add_watch(context->fd, DEV_DIR, IN_CREATE | IN_DELETE);
if (wdd < 0) {
context->wdd = inotify_add_watch(context->fd, DEV_DIR, IN_CREATE | IN_DELETE);
if (context->wdd < 0) {
fprintf(stderr, "inotify_add_watch failed\n");
if (discovery_done_cb)
discovery_done_cb(client_data);
return;
return done;
}

watch_existing_subdirs(context, wds, wd_count);
watch_existing_subdirs(context, context->wds, MAX_USBFS_WD_COUNT);

/* check for existing devices first, after we have inotify set up */
done = find_existing_devices(added_cb, client_data);
if (discovery_done_cb)
done |= discovery_done_cb(client_data);

while (!done) {
ret = read(context->fd, event_buf, sizeof(event_buf));
if (ret >= (int)sizeof(struct inotify_event)) {
event = (struct inotify_event *)event_buf;
wd = event->wd;
if (wd == wdd) {
if ((event->mask & IN_CREATE) && !strcmp(event->name, "bus")) {
watch_existing_subdirs(context, wds, wd_count);
done = find_existing_devices(added_cb, client_data);
} else if ((event->mask & IN_DELETE) && !strcmp(event->name, "bus")) {
for (i = 0; i < wd_count; i++) {
if (wds[i] >= 0) {
inotify_rm_watch(context->fd, wds[i]);
wds[i] = -1;
}
return done;
} /* usb_host_load() */

int usb_host_read_event(struct usb_host_context *context)
{
struct inotify_event* event;
char event_buf[512];
char path[100];
int i, ret, done = 0;
int j, event_size;
int wd;

ret = read(context->fd, event_buf, sizeof(event_buf));
if (ret >= (int)sizeof(struct inotify_event)) {
event = (struct inotify_event *)event_buf;
wd = event->wd;
if (wd == context->wdd) {
if ((event->mask & IN_CREATE) && !strcmp(event->name, "bus")) {
watch_existing_subdirs(context, context->wds, MAX_USBFS_WD_COUNT);
done = find_existing_devices(context->cb_added, context->data);
} else if ((event->mask & IN_DELETE) && !strcmp(event->name, "bus")) {
for (i = 0; i < MAX_USBFS_WD_COUNT; i++) {
if (context->wds[i] >= 0) {
inotify_rm_watch(context->fd, context->wds[i]);
context->wds[i] = -1;
}
}
} else if (wd == wds[0]) {
i = atoi(event->name);
snprintf(path, sizeof(path), "%s/%s", USB_FS_DIR, event->name);
D("%s subdirectory %s: index: %d\n", (event->mask & IN_CREATE) ?
"new" : "gone", path, i);
if (i > 0 && i < wd_count) {
if (event->mask & IN_CREATE) {
ret = inotify_add_watch(context->fd, path,
IN_CREATE | IN_DELETE);
if (ret >= 0)
wds[i] = ret;
done = find_existing_devices_bus(path, added_cb,
client_data);
} else if (event->mask & IN_DELETE) {
inotify_rm_watch(context->fd, wds[i]);
wds[i] = -1;
}
}
} else if (wd == context->wds[0]) {
i = atoi(event->name);
snprintf(path, sizeof(path), USB_FS_DIR "/%s", event->name);
D("%s subdirectory %s: index: %d\n", (event->mask & IN_CREATE) ?
"new" : "gone", path, i);
if (i > 0 && i < MAX_USBFS_WD_COUNT) {
if (event->mask & IN_CREATE) {
ret = inotify_add_watch(context->fd, path,
IN_CREATE | IN_DELETE);
if (ret >= 0)
context->wds[i] = ret;
done = find_existing_devices_bus(path, context->cb_added,
context->data);
} else if (event->mask & IN_DELETE) {
inotify_rm_watch(context->fd, context->wds[i]);
context->wds[i] = -1;
}
} else {
for (i = 1; i < wd_count && !done; i++) {
if (wd == wds[i]) {
snprintf(path, sizeof(path), "%s/%03d/%s", USB_FS_DIR, i, event->name);
if (event->mask == IN_CREATE) {
D("new device %s\n", path);
done = added_cb(path, client_data);
} else if (event->mask == IN_DELETE) {
D("gone device %s\n", path);
done = removed_cb(path, client_data);
}
}
} else {
for (i = 1; (i < MAX_USBFS_WD_COUNT) && !done; i++) {
if (wd == context->wds[i]) {
snprintf(path, sizeof(path), USB_FS_DIR "/%03d/%s", i, event->name);
if (event->mask == IN_CREATE) {
D("new device %s\n", path);
done = context->cb_added(path, context->data);
} else if (event->mask == IN_DELETE) {
D("gone device %s\n", path);
done = context->cb_removed(path, context->data);
}
}
}
}
}
}

return done;
} /* usb_host_read_event() */

void usb_host_run(struct usb_host_context *context,
usb_device_added_cb added_cb,
usb_device_removed_cb removed_cb,
usb_discovery_done_cb discovery_done_cb,
void *client_data)
{
int done;

done = usb_host_load(context, added_cb, removed_cb, discovery_done_cb, client_data);

while (!done) {

done = usb_host_read_event(context);
}
} /* usb_host_run() */

struct usb_device *usb_device_open(const char *dev_name)
{
@@ -606,7 +647,6 @@ struct usb_request *usb_request_wait(struct usb_device *dev)
{
struct usbdevfs_urb *urb = NULL;
struct usb_request *req = NULL;
int res;

while (1) {
int res = ioctl(dev->fd, USBDEVFS_REAPURB, &urb);

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