driver: qmi_qrtr: Allow selecting SIM slot using environment variable (…

…#97)

Introduce the UIM_SLOT variable which can be set to the SIM slot you
want to manage. Commonly '1' and '2' are available for dual SIM devices,
though nothing should be preventing it from potential 3-or-more SIM slot
devices.

Co-authored-by: Luca Weiss <luca.weiss@fairphone.com>

driver/apdu/qmi_qrtr.c

@@ -13,9 +13,8 @@
 #include <libqrtr-glib.h>
 #include "qmi_qrtr_helpers.h"
 
-#define UIM_SLOT 2 // TODO: Make this runtime-configurable
-
 static int lastChannelId = -1;
+static int uimSlot = -1;
 static GMainContext *context = NULL;
 static QrtrBus *bus = NULL;
 static QmiClientUim *uimClient = NULL;
@@ -99,7 +98,7 @@ static int apdu_interface_transmit(struct euicc_ctx *ctx, uint8_t **rx, uint32_t
 
     QmiMessageUimSendApduInput *input;
     input = qmi_message_uim_send_apdu_input_new ();
-    qmi_message_uim_send_apdu_input_set_slot (input, UIM_SLOT, NULL);
+    qmi_message_uim_send_apdu_input_set_slot (input, uimSlot, NULL);
     qmi_message_uim_send_apdu_input_set_channel_id (input, lastChannelId, NULL);
     qmi_message_uim_send_apdu_input_set_apdu (input, apdu_data, NULL);
 
@@ -143,7 +142,7 @@ static int apdu_interface_logic_channel_open(struct euicc_ctx *ctx, const uint8_
 
     QmiMessageUimOpenLogicalChannelInput *input;
     input = qmi_message_uim_open_logical_channel_input_new ();
-    qmi_message_uim_open_logical_channel_input_set_slot (input, UIM_SLOT, NULL);
+    qmi_message_uim_open_logical_channel_input_set_slot (input, uimSlot, NULL);
     qmi_message_uim_open_logical_channel_input_set_aid (input, aid_data, NULL);
 
     QmiMessageUimOpenLogicalChannelOutput *output;
@@ -181,7 +180,7 @@ static void apdu_interface_logic_channel_close(struct euicc_ctx *ctx, uint8_t ch
 
     QmiMessageUimLogicalChannelInput *input;
     input = qmi_message_uim_logical_channel_input_new ();
-    qmi_message_uim_logical_channel_input_set_slot (input, UIM_SLOT, NULL);
+    qmi_message_uim_logical_channel_input_set_slot (input, uimSlot, NULL);
     qmi_message_uim_logical_channel_input_set_channel_id (input, channel, NULL);
 
     QmiMessageUimLogicalChannelOutput *output;
@@ -237,6 +236,16 @@ static int libapduinterface_init(struct euicc_apdu_interface *ifstruct)
     atexit(cleanup);
     signal(SIGINT, sighandler);
 
+    /*
+     * Allow the user to select the SIM card slot via environment variable.
+     * Use the primary SIM slot if not set.
+     */
+    if (getenv("UIM_SLOT")) {
+        uimSlot = atoi(getenv("UIM_SLOT"));
+    } else {
+        uimSlot = 1;
+    }
+
     return 0;
 }