From b1807797a32435c934fb0034d183bfdbb60078a5 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Wed, 8 Nov 2023 00:11:55 -0800
Subject: [PATCH] Make sure joysticks are locked when adding and removing them
Fixes https://github.com/libsdl-org/SDL/issues/8146
(cherry picked from commit ed1e0c1530e7902d6562f8e8cab2aa38e829a834)
---
src/joystick/linux/SDL_sysjoystick.c | 94 ++++++++++++++++++----------
1 file changed, 62 insertions(+), 32 deletions(-)
diff --git a/src/joystick/linux/SDL_sysjoystick.c b/src/joystick/linux/SDL_sysjoystick.c
index 1862785fe391..9652351c1430 100644
--- a/src/joystick/linux/SDL_sysjoystick.c
+++ b/src/joystick/linux/SDL_sysjoystick.c
@@ -146,8 +146,8 @@ typedef enum
static EnumerationMethod enumeration_method = ENUMERATION_UNSET;
static SDL_bool IsJoystickJSNode(const char *node);
-static int MaybeAddDevice(const char *path);
-static int MaybeRemoveDevice(const char *path);
+static void MaybeAddDevice(const char *path);
+static void MaybeRemoveDevice(const char *path);
/* A linked list of available joysticks */
typedef struct SDL_joylist_item
@@ -177,10 +177,10 @@ typedef struct SDL_sensorlist_item
} SDL_sensorlist_item;
static SDL_bool SDL_classic_joysticks = SDL_FALSE;
-static SDL_joylist_item *SDL_joylist = NULL;
-static SDL_joylist_item *SDL_joylist_tail = NULL;
-static int numjoysticks = 0;
-static SDL_sensorlist_item *SDL_sensorlist = NULL;
+static SDL_joylist_item *SDL_joylist SDL_GUARDED_BY(SDL_joystick_lock) = NULL;
+static SDL_joylist_item *SDL_joylist_tail SDL_GUARDED_BY(SDL_joystick_lock) = NULL;
+static int numjoysticks SDL_GUARDED_BY(SDL_joystick_lock) = 0;
+static SDL_sensorlist_item *SDL_sensorlist SDL_GUARDED_BY(SDL_joystick_lock) = NULL;
static int inotify_fd = -1;
static Uint32 last_joy_detect_time;
@@ -380,7 +380,7 @@ static void FreeSensorlistItem(SDL_sensorlist_item *item)
SDL_free(item);
}
-static int MaybeAddDevice(const char *path)
+static void MaybeAddDevice(const char *path)
{
struct stat sb;
int fd = -1;
@@ -390,28 +390,30 @@ static int MaybeAddDevice(const char *path)
SDL_sensorlist_item *item_sensor;
if (path == NULL) {
- return -1;
+ return;
}
if (stat(path, &sb) == -1) {
- return -1;
+ return;
}
+ SDL_LockJoysticks();
+
/* Check to make sure it's not already in list. */
for (item = SDL_joylist; item != NULL; item = item->next) {
if (sb.st_rdev == item->devnum) {
- return -1; /* already have this one */
+ goto done; /* already have this one */
}
}
for (item_sensor = SDL_sensorlist; item_sensor != NULL; item_sensor = item_sensor->next) {
if (sb.st_rdev == item_sensor->devnum) {
- return -1; /* already have this one */
+ goto done; /* already have this one */
}
}
fd = open(path, O_RDONLY | O_CLOEXEC, 0);
if (fd < 0) {
- return -1;
+ goto done;
}
#ifdef DEBUG_INPUT_EVENTS
@@ -426,7 +428,7 @@ static int MaybeAddDevice(const char *path)
item = (SDL_joylist_item *)SDL_calloc(1, sizeof(SDL_joylist_item));
if (item == NULL) {
SDL_free(name);
- return -1;
+ goto done;
}
item->devnum = sb.st_rdev;
@@ -436,7 +438,7 @@ static int MaybeAddDevice(const char *path)
if ((item->path == NULL) || (item->name == NULL)) {
FreeJoylistItem(item);
- return -1;
+ goto done;
}
item->device_instance = SDL_GetNextJoystickInstanceID();
@@ -451,7 +453,7 @@ static int MaybeAddDevice(const char *path)
++numjoysticks;
SDL_PrivateJoystickAdded(item->device_instance);
- return numjoysticks;
+ goto done;
}
if (IsSensor(path, fd)) {
@@ -461,27 +463,30 @@ static int MaybeAddDevice(const char *path)
close(fd);
item_sensor = (SDL_sensorlist_item *)SDL_calloc(1, sizeof(SDL_sensorlist_item));
if (item_sensor == NULL) {
- return -1;
+ goto done;
}
item_sensor->devnum = sb.st_rdev;
item_sensor->path = SDL_strdup(path);
if (item_sensor->path == NULL) {
FreeSensorlistItem(item_sensor);
- return -1;
+ goto done;
}
item_sensor->next = SDL_sensorlist;
SDL_sensorlist = item_sensor;
- return -1;
+ goto done;
}
close(fd);
- return -1;
+done:
+ SDL_UnlockJoysticks();
}
static void RemoveJoylistItem(SDL_joylist_item *item, SDL_joylist_item *prev)
{
+ SDL_AssertJoysticksLocked();
+
if (item->hwdata) {
item->hwdata->item = NULL;
}
@@ -506,6 +511,8 @@ static void RemoveJoylistItem(SDL_joylist_item *item, SDL_joylist_item *prev)
static void RemoveSensorlistItem(SDL_sensorlist_item *item, SDL_sensorlist_item *prev)
{
+ SDL_AssertJoysticksLocked();
+
if (item->hwdata) {
item->hwdata->item_sensor = NULL;
}
@@ -522,7 +529,7 @@ static void RemoveSensorlistItem(SDL_sensorlist_item *item, SDL_sensorlist_item
FreeSensorlistItem(item);
}
-static int MaybeRemoveDevice(const char *path)
+static void MaybeRemoveDevice(const char *path)
{
SDL_joylist_item *item;
SDL_joylist_item *prev = NULL;
@@ -530,15 +537,15 @@ static int MaybeRemoveDevice(const char *path)
SDL_sensorlist_item *prev_sensor = NULL;
if (path == NULL) {
- return -1;
+ return;
}
+ SDL_LockJoysticks();
for (item = SDL_joylist; item != NULL; item = item->next) {
/* found it, remove it. */
if (SDL_strcmp(path, item->path) == 0) {
- const int retval = item->device_instance;
RemoveJoylistItem(item, prev);
- return retval;
+ goto done;
}
prev = item;
}
@@ -546,21 +553,24 @@ static int MaybeRemoveDevice(const char *path)
/* found it, remove it. */
if (SDL_strcmp(path, item_sensor->path) == 0) {
RemoveSensorlistItem(item_sensor, prev_sensor);
- return -1;
+ goto done;
}
prev_sensor = item_sensor;
}
-
- return -1;
+done:
+ SDL_UnlockJoysticks();
}
static void HandlePendingRemovals(void)
{
SDL_joylist_item *prev = NULL;
- SDL_joylist_item *item = SDL_joylist;
+ SDL_joylist_item *item = NULL;
SDL_sensorlist_item *prev_sensor = NULL;
- SDL_sensorlist_item *item_sensor = SDL_sensorlist;
+ SDL_sensorlist_item *item_sensor = NULL;
+ SDL_AssertJoysticksLocked();
+
+ item = SDL_joylist;
while (item != NULL) {
if (item->hwdata && item->hwdata->gone) {
RemoveJoylistItem(item, prev);
@@ -576,6 +586,7 @@ static void HandlePendingRemovals(void)
}
}
+ item_sensor = SDL_sensorlist;
while (item_sensor != NULL) {
if (item_sensor->hwdata && item_sensor->hwdata->sensor_gone) {
RemoveSensorlistItem(item_sensor, prev_sensor);
@@ -612,6 +623,7 @@ static SDL_bool SteamControllerConnectedCallback(const char *name, SDL_JoystickG
}
*device_instance = item->device_instance = SDL_GetNextJoystickInstanceID();
+ SDL_LockJoysticks();
if (SDL_joylist_tail == NULL) {
SDL_joylist = SDL_joylist_tail = item;
} else {
@@ -623,6 +635,7 @@ static SDL_bool SteamControllerConnectedCallback(const char *name, SDL_JoystickG
++numjoysticks;
SDL_PrivateJoystickAdded(item->device_instance);
+ SDL_UnlockJoysticks();
return SDL_TRUE;
}
@@ -632,14 +645,16 @@ static void SteamControllerDisconnectedCallback(int device_instance)
SDL_joylist_item *item;
SDL_joylist_item *prev = NULL;
+ SDL_LockJoysticks();
for (item = SDL_joylist; item != NULL; item = item->next) {
/* found it, remove it. */
if (item->device_instance == device_instance) {
RemoveJoylistItem(item, prev);
- return;
+ break;
}
prev = item;
}
+ SDL_UnlockJoysticks();
}
static int StrHasPrefix(const char *string, const char *prefix)
@@ -965,17 +980,22 @@ static int LINUX_JoystickInit(void)
static int LINUX_JoystickGetCount(void)
{
+ SDL_AssertJoysticksLocked();
+
return numjoysticks;
}
static SDL_joylist_item *JoystickByDevIndex(int device_index)
{
- SDL_joylist_item *item = SDL_joylist;
+ SDL_joylist_item *item;
+
+ SDL_AssertJoysticksLocked();
if ((device_index < 0) || (device_index >= numjoysticks)) {
return NULL;
}
+ item = SDL_joylist;
while (device_index > 0) {
SDL_assert(item != NULL);
device_index--;
@@ -1405,6 +1425,8 @@ static SDL_sensorlist_item *GetSensor(SDL_joylist_item *item)
char uniq_item[128];
int fd_item = -1;
+ SDL_AssertJoysticksLocked();
+
if (item == NULL || SDL_sensorlist == NULL) {
return NULL;
}
@@ -1458,11 +1480,12 @@ static SDL_sensorlist_item *GetSensor(SDL_joylist_item *item)
*/
static int LINUX_JoystickOpen(SDL_Joystick *joystick, int device_index)
{
- SDL_joylist_item *item = JoystickByDevIndex(device_index);
- SDL_sensorlist_item *item_sensor = GetSensor(item);
+ SDL_joylist_item *item;
+ SDL_sensorlist_item *item_sensor;
SDL_AssertJoysticksLocked();
+ item = JoystickByDevIndex(device_index);
if (item == NULL) {
return SDL_SetError("No such device");
}
@@ -1474,6 +1497,7 @@ static int LINUX_JoystickOpen(SDL_Joystick *joystick, int device_index)
return SDL_OutOfMemory();
}
+ item_sensor = GetSensor(item);
if (PrepareJoystickHwdata(joystick, item, item_sensor) == -1) {
SDL_free(joystick->hwdata);
joystick->hwdata = NULL;
@@ -1578,6 +1602,8 @@ static int LINUX_JoystickSendEffect(SDL_Joystick *joystick, const void *data, in
static int LINUX_JoystickSetSensorsEnabled(SDL_Joystick *joystick, SDL_bool enabled)
{
+ SDL_AssertJoysticksLocked();
+
if (!joystick->hwdata->has_accelerometer && !joystick->hwdata->has_gyro) {
return SDL_Unsupported();
}
@@ -1759,6 +1785,8 @@ static void PollAllSensors(SDL_Joystick *joystick)
struct input_absinfo absinfo;
int i;
+ SDL_AssertJoysticksLocked();
+
SDL_assert(joystick->hwdata->fd_sensor >= 0);
if (joystick->hwdata->has_gyro) {
@@ -2092,6 +2120,8 @@ static void LINUX_JoystickQuit(void)
SDL_sensorlist_item *item_sensor = NULL;
SDL_sensorlist_item *next_sensor = NULL;
+ SDL_AssertJoysticksLocked();
+
if (inotify_fd >= 0) {
close(inotify_fd);
inotify_fd = -1;