From 14afdf38e371e57db39d6236f60f5458a0bdb0d8 Mon Sep 17 00:00:00 2001
From: David Ward <david.ward@ll.mit.edu>
Date: Fri, 18 May 2018 07:11:49 -0400
Subject: [PATCH] Do not temporarily set SC_READER_REMOVED on all readers
 (#1335)

* reader-pcsc: Do not temporarily set SC_READER_REMOVED on all readers

Fixes #1324.

* reader-cryptotokenkit: Do not temporarily set SC_READER_REMOVED on all readers

See #1324.
---
 src/libopensc/reader-cryptotokenkit.m | 51 ++++++++++++++++-----------------
 src/libopensc/reader-pcsc.c           | 53 +++++++++++++++++++----------------
 2 files changed, 55 insertions(+), 49 deletions(-)

diff --git a/src/libopensc/reader-cryptotokenkit.m b/src/libopensc/reader-cryptotokenkit.m
index cf0774697..449b9f86d 100644
--- a/src/libopensc/reader-cryptotokenkit.m
+++ b/src/libopensc/reader-cryptotokenkit.m
@@ -543,8 +543,10 @@ int cryptotokenkit_use_reader(sc_context_t *ctx, void *pcsc_context_handle, void
 static int cryptotokenkit_detect_readers(sc_context_t *ctx)
 {
 	size_t i;
+	NSUInteger j;
 	int r;
 	TKSmartCardSlotManager *mngr = [TKSmartCardSlotManager defaultManager];
+	NSMutableArray *slotNames;
 
 	LOG_FUNC_CALLED(ctx);
 
@@ -554,38 +556,37 @@ static int cryptotokenkit_detect_readers(sc_context_t *ctx)
 	 	goto err;
 	}
 
-	/* temporarily mark all readers as removed */
-	for (i=0; i < sc_ctx_get_reader_count(ctx); i++) {
-		sc_reader_t *reader = sc_ctx_get_reader(ctx, i);
-		reader->flags |= SC_READER_REMOVED;
-	}
-
 	sc_log(ctx, "Probing CryptoTokenKit readers");
 
-	for (NSString *slotName in [mngr slotNames]) {
-		sc_reader_t *old_reader;
-		int found = 0;
-		const char *reader_name = [slotName UTF8String];
-		dispatch_semaphore_t sema = dispatch_semaphore_create(0);
+	slotNames = [[mngr slotNames] mutableCopy];
 
-		for (i=0; i < sc_ctx_get_reader_count(ctx) && !found; i++) {
-			old_reader = sc_ctx_get_reader(ctx, i);
-			if (old_reader == NULL) {
-				r = SC_ERROR_INTERNAL;
-				goto err;
-			}
-			if (!strcmp(old_reader->name, reader_name)) {
-				found = 1;
-			}
+	/* check if existing readers were returned in the list */
+	for (i = 0; i < sc_ctx_get_reader_count(ctx); i++) {
+		sc_reader_t *reader = sc_ctx_get_reader(ctx, i);
+
+		if (reader == NULL) {
+			r = SC_ERROR_INTERNAL;
+			goto err;
+		}
+
+		for (j = 0; j < [slotNames count]; j++) {
+			if (!strcmp(reader->name, [slotNames[j] UTF8String]))
+				break;
 		}
 
-		/* Reader already available, skip */
-		if (found) {
-			old_reader->flags &= ~SC_READER_REMOVED;
-			continue;
+		if (j < [slotNames count]) {
+			/* existing reader found; remove it from the list */
+			[slotNames removeObjectAtIndex:j];
+		} else {
+			/* existing reader not found */
+			reader->flags |= SC_READER_REMOVED;
 		}
+	}
 
-		sc_log(ctx, "Found new CryptoTokenKit reader '%s'", reader_name);
+	/* add readers remaining in the list */
+	for (NSString *slotName in slotNames) {
+		dispatch_semaphore_t sema = dispatch_semaphore_create(0);
+		sc_log(ctx, "Found new CryptoTokenKit reader '%s'", [slotName UTF8String]);
 		[mngr getSlotWithName:slotName reply:^(TKSmartCardSlot *slot) {
 			cryptotokenkit_use_reader(ctx, slot, NULL);
 		 	dispatch_semaphore_signal(sema);
diff --git a/src/libopensc/reader-pcsc.c b/src/libopensc/reader-pcsc.c
index 18d97f0c8..c9edad608 100644
--- a/src/libopensc/reader-pcsc.c
+++ b/src/libopensc/reader-pcsc.c
@@ -1298,12 +1298,6 @@ static int pcsc_detect_readers(sc_context_t *ctx)
 		goto out;
 	}
 
-	/* temporarily mark all readers as removed */
-	for (i=0;i < sc_ctx_get_reader_count(ctx);i++) {
-		sc_reader_t *reader = sc_ctx_get_reader(ctx, i);
-		reader->flags |= SC_READER_REMOVED;
-	}
-
 	sc_log(ctx, "Probing PC/SC readers");
 
 	do {
@@ -1359,28 +1353,39 @@ static int pcsc_detect_readers(sc_context_t *ctx)
 		goto out;
 	}
 
-	for (reader_name = reader_buf; *reader_name != '\x0';
-		   	reader_name += strlen(reader_name) + 1) {
-		sc_reader_t *reader = NULL, *old_reader = NULL;
-		struct pcsc_private_data *priv = NULL;
-		int found = 0;
+	/* check if existing readers were returned in the list */
+	for (i = 0; i < sc_ctx_get_reader_count(ctx); i++) {
+		sc_reader_t *reader = sc_ctx_get_reader(ctx, i);
 
-		for (i=0;i < sc_ctx_get_reader_count(ctx) && !found;i++) {
-			old_reader = sc_ctx_get_reader(ctx, i);
-			if (old_reader == NULL) {
-				ret = SC_ERROR_INTERNAL;
-				goto out;
-			}
-			if (!strcmp(old_reader->name, reader_name)) {
-				found = 1;
-			}
+		if (!reader) {
+			ret = SC_ERROR_INTERNAL;
+			goto out;
 		}
 
-		/* Reader already available, skip */
-		if (found) {
-			old_reader->flags &= ~SC_READER_REMOVED;
-			continue;
+		for (reader_name = reader_buf; *reader_name != '\x0';
+				reader_name += strlen(reader_name) + 1) {
+			if (!strcmp(reader->name, reader_name))
+				break;
+		}
+
+		if (*reader_name != '\x0') {
+			/* existing reader found; remove it from the list */
+			char *next_reader_name = reader_name + strlen(reader_name) + 1;
+
+			memmove(reader_name, next_reader_name,
+					(reader_buf + reader_buf_size) - next_reader_name);
+			reader_buf_size -= (next_reader_name - reader_name);
+		} else {
+			/* existing reader not found */
+			reader->flags |= SC_READER_REMOVED;
 		}
+	}
+
+	/* add readers remaining in the list */
+	for (reader_name = reader_buf; *reader_name != '\x0';
+		   	reader_name += strlen(reader_name) + 1) {
+		sc_reader_t *reader = NULL;
+		struct pcsc_private_data *priv = NULL;
 
 		ret = pcsc_add_reader(ctx, reader_name, strlen(reader_name), &reader);
 		if (ret != SC_SUCCESS) {