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Fixed so storeCommand/getCommand are multithread-safe (at least dual-thread). Hopefully. http://www.proxmark.org/forum/viewtopic.php?pid=7400#p7400

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martin.holst@gmail.com 2013-06-06 18:30:00 +00:00
parent c338502409
commit 1bad971361
1 changed files with 4 additions and 17 deletions
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21
client/cmdmain.c
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@ -39,7 +39,7 @@ static UsbCommand cmdBuffer[CMD_BUFFER_SIZE];
//Points to the next empty position to write to //Points to the next empty position to write to
static int cmd_head;//Starts as 0 static int cmd_head;//Starts as 0
//Points to the position of the last unread command //Points to the position of the last unread command
static int cmd_tail = -1;//Starts as -1 static int cmd_tail;//Starts as 0
static command_t CommandTable[] = static command_t CommandTable[] =
{ {
@ -211,7 +211,7 @@ void UsbCommandReceived(UsbCommand *UC)
*/ */
void storeCommand(UsbCommand *command) void storeCommand(UsbCommand *command)
{ {
if(cmd_head == cmd_tail) if( ( cmd_head+1) % CMD_BUFFER_SIZE == cmd_tail)
{ {
//If these two are equal, we're about to overwrite in the //If these two are equal, we're about to overwrite in the
// circular buffer. // circular buffer.
@ -221,14 +221,7 @@ void storeCommand(UsbCommand *command)
UsbCommand* destination = &cmdBuffer[cmd_head]; UsbCommand* destination = &cmdBuffer[cmd_head];
memcpy(destination, command, sizeof(UsbCommand)); memcpy(destination, command, sizeof(UsbCommand));
//Also, if cmd_tail is still -1 because the buffer was cmd_head = (cmd_head +1) % CMD_BUFFER_SIZE; //increment head and wrap
// previously empty, set it to head
if(cmd_tail < 0) {
cmd_tail = cmd_head;
}
cmd_head++; //increment head
cmd_head %= CMD_BUFFER_SIZE;//wrap around
} }
/** /**
@ -239,7 +232,7 @@ void storeCommand(UsbCommand *command)
int getCommand(UsbCommand* response) int getCommand(UsbCommand* response)
{ {
//If head == tail, there's nothing to read, or if we just got initialized //If head == tail, there's nothing to read, or if we just got initialized
if(cmd_head == cmd_tail || cmd_tail == -1){ if(cmd_head == cmd_tail){
return 0; return 0;
} }
//Pick out the next unread command //Pick out the next unread command
@ -247,12 +240,6 @@ int getCommand(UsbCommand* response)
memcpy(response, last_unread, sizeof(UsbCommand)); memcpy(response, last_unread, sizeof(UsbCommand));
//Increment tail - this is a circular buffer, so modulo buffer size //Increment tail - this is a circular buffer, so modulo buffer size
cmd_tail = (cmd_tail +1 ) % CMD_BUFFER_SIZE; cmd_tail = (cmd_tail +1 ) % CMD_BUFFER_SIZE;
//In order to detect when the buffer overwrites itself, we set the
// tail to -1 whenever it 'catches up' with head : this means the buffer is empty.
// Otherwise, head==tail could mean both: either empty or full.
if(cmd_tail == cmd_head){
cmd_tail = -1 ;
}
return 1; return 1;