start moving code to the library, and add error codes

.gitignore

@@ -37,6 +37,8 @@ yubico-piv-tool-*-mac.zip.sig
 tests/basic.sh.log
 tests/basic.sh.trs
 tests/test-suite.log
+lib/error.lo
+lib/error.o
 lib/libykpiv.la
 lib/version.lo
 lib/version.o

configure.ac

@@ -136,6 +136,7 @@ if test "$gl_gcc_warnings" = yes; then
   nw="$nw -Wtraditional-conversion" # Too many warnings for now
   nw="$nw -Wconversion"             # Too many warnings for now
   nw="$nw -Wsuggest-attribute=pure" # Is it worth using attributes?
+  nw="$nw -Wsuggest-attribute=const" # Is it worth using attributes?
 
   gl_MANYWARN_ALL_GCC([ws])
   gl_MANYWARN_COMPLEMENT(ws, [$ws], [$nw])

lib/Makefile.am

@@ -30,6 +30,7 @@ AM_CPPFLAGS = $(OPENSSL_CFLAGS) $(PCSC_CFLAGS)
 lib_LTLIBRARIES = libykpiv.la
 
 libykpiv_la_SOURCES = ykpiv.c version.c ykpiv.pc.in ykpiv.map internal.h
+libykpiv_la_SOURCES += error.c
 libykpiv_la_includedir = $(includedir)/ykpiv
 libykpiv_la_include_HEADERS = ykpiv.h ykpiv-version.h
 

lib/error.c

@@ -0,0 +1,95 @@
+ /*
+ * Copyright (c) 2014 Yubico AB
+ * All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Additional permission under GNU GPL version 3 section 7
+ *
+ * If you modify this program, or any covered work, by linking or
+ * combining it with the OpenSSL project's OpenSSL library (or a
+ * modified version of that library), containing parts covered by the
+ * terms of the OpenSSL or SSLeay licenses, We grant you additional 
+ * permission to convey the resulting work. Corresponding Source for a
+ * non-source form of such a combination shall include the source code
+ * for the parts of OpenSSL used as well as that of the covered work.
+ *
+ */
+
+#include "ykpiv.h"
+
+#include <stddef.h>
+
+#define ERR(name, desc) { name, #name, desc }
+
+typedef struct
+{
+  ykpiv_rc rc;
+  const char *name;
+  const char *description;
+} err_t;
+
+static const err_t errors[] = {
+  ERR (YKPIV_OK, "Successful return"),
+  ERR (YKPIV_MEMORY_ERROR, "Error allocating memory"),
+  ERR (YKPIV_PCSC_ERROR, "Error in PCSC call"),
+};
+
+/**
+ * ykpiv_strerror:
+ * @err: error code
+ *
+ * Convert return code to human readable string explanation of the
+ * reason for the particular error code.
+ *
+ * This string can be used to output a diagnostic message to the user.
+ *
+ * Return value: Returns a pointer to a statically allocated string
+ *   containing an explanation of the error code @err.
+ **/
+const char *ykpiv_strerror(ykpiv_rc err) {
+  static const char *unknown = "Unknown ykpiv error";
+  const char *p;
+
+  if (-err < 0 || -err >= (int) (sizeof (errors) / sizeof (errors[0])))
+    return unknown;
+
+  p = errors[-err].description;
+  if (!p)
+    p = unknown;
+
+  return p;
+}
+
+
+/**
+ * ykpiv_strerror_name:
+ * @err: error code
+ *
+ * Convert return code to human readable string representing the error
+ * code symbol itself.  For example, ykpiv_strerror_name(%YKPIV_OK)
+ * returns the string "YKPIV_OK".
+ *
+ * This string can be used to output a diagnostic message to the user.
+ *
+ * Return value: Returns a pointer to a statically allocated string
+ *   containing a string version of the error code @err, or NULL if
+ *   the error code is not known.
+ **/
+const char *ykpiv_strerror_name(ykpiv_rc err) {
+  if (-err < 0 || -err >= (int) (sizeof (errors) / sizeof (errors[0])))
+    return NULL;
+
+  return errors[-err].name;
+}

lib/internal.h

@@ -30,9 +30,25 @@
 #ifndef YKPIV_INTERNAL_H
 #define YKPIV_INTERNAL_H
 
+#include <stdbool.h>
+
+#if BACKEND_PCSC
+#if defined HAVE_PCSC_WINSCARD_H
+# include <PCSC/wintypes.h>
+# include <PCSC/winscard.h>
+#else
+# include <winscard.h>
+#endif
+#endif
+
 struct ykpiv_state {
-	SCARDCONTEXT card;
+	SCARDCONTEXT context;
-	SCARDHANDLE cardHandle;
+	SCARDHANDLE card;
+	int verbose;
+};
+
+unsigned const char aid[] = {
+	0xa0, 0x00, 0x00, 0x03, 0x08
 };
 
 #endif

lib/ykpiv.c

@@ -29,30 +29,99 @@
 
 #include <stdlib.h>
 #include <string.h>
-
+#include <stdio.h>
-#if BACKEND_PCSC
-#if defined HAVE_PCSC_WINSCARD_H
-# include <PCSC/wintypes.h>
-# include <PCSC/winscard.h>
-#else
-# include <winscard.h>
-#endif
-#endif
 
 #include "internal.h"
 #include "ykpiv.h"
 
-int ykpiv_init(ykpiv_state **state) {
+ykpiv_rc ykpiv_init(ykpiv_state **state, int verbose) {
-	ykpiv_state *s = malloc(sizeof(ykpiv_state));
+  ykpiv_state *s = malloc(sizeof(ykpiv_state));
-	if(s == NULL) {
+  if(s == NULL) {
-		return -1;
+    return YKPIV_MEMORY_ERROR;
-	}
+  }
-	memset(s, 0, sizeof(ykpiv_state));
+  memset(s, 0, sizeof(ykpiv_state));
-	*state = s;
+  s->verbose = verbose;
-	return 0;
+  *state = s;
+  return YKPIV_OK;
 }
 
-int ykpiv_done(ykpiv_state *state) {
+ykpiv_rc ykpiv_done(ykpiv_state *state) {
-	free(state);
+  free(state);
-	return 0;
+  return YKPIV_OK;
+}
+
+ykpiv_rc ykpiv_connect(ykpiv_state *state, const char *wanted) {
+  unsigned long num_readers = 0;
+  unsigned long active_protocol;
+  char reader_buf[1024];
+  long rc;
+  char *reader_ptr;
+
+  rc = SCardEstablishContext(SCARD_SCOPE_SYSTEM, NULL, NULL, &state->context);
+  if (rc != SCARD_S_SUCCESS) {
+    if(state->verbose) {
+      fprintf (stderr, "error: SCardEstablishContext failed, rc=%08lx\n", rc);
+    }
+    return YKPIV_PCSC_ERROR;
+  }
+
+  rc = SCardListReaders(state->context, NULL, NULL, &num_readers);
+  if (rc != SCARD_S_SUCCESS) {
+    if(state->verbose) {
+      fprintf (stderr, "error: SCardListReaders failed, rc=%08lx\n", rc);
+    }
+    SCardReleaseContext(state->context);
+    return YKPIV_PCSC_ERROR;
+  }
+
+  if (num_readers > sizeof(reader_buf)) {
+    num_readers = sizeof(reader_buf);
+  }
+
+  rc = SCardListReaders(state->context, NULL, reader_buf, &num_readers);
+  if (rc != SCARD_S_SUCCESS)
+  {
+    if(state->verbose) {
+      fprintf (stderr, "error: SCardListReaders failed, rc=%08lx\n", rc);
+    }
+    SCardReleaseContext(state->context);
+    return YKPIV_PCSC_ERROR;
+  }
+
+  reader_ptr = reader_buf;
+  if(wanted) {
+    while(*reader_ptr != '\0') {
+      if(strstr(reader_ptr, wanted)) {
+	if(state->verbose) {
+	  fprintf(stderr, "using reader '%s' matching '%s'.\n", reader_ptr, wanted);
+	}
+	break;
+      } else {
+	if(state->verbose) {
+	  fprintf(stderr, "skipping reader '%s' since it doesn't match.\n", reader_ptr);
+	}
+	reader_ptr += strlen(reader_ptr) + 1;
+      }
+    }
+  }
+  if(*reader_ptr == '\0') {
+    if(state->verbose) {
+      fprintf(stderr, "error: no useable reader found.\n");
+    }
+    SCardReleaseContext(state->context);
+    return YKPIV_PCSC_ERROR;
+  }
+
+  rc = SCardConnect(state->context, reader_ptr, SCARD_SHARE_SHARED,
+      SCARD_PROTOCOL_T1, &state->card, &active_protocol);
+  if(rc != SCARD_S_SUCCESS)
+  {
+    if(state->verbose) {
+      fprintf(stderr, "error: SCardConnect failed, rc=%08lx\n", rc);
+    }
+    SCardReleaseContext(state->context);
+    return YKPIV_PCSC_ERROR;
+  }
+
+  return YKPIV_OK;
 }

lib/ykpiv.h

@@ -37,8 +37,20 @@ extern "C"
 
 	typedef struct ykpiv_state ykpiv_state;
 
-	int ykpiv_init(ykpiv_state **state);
+	typedef enum {
-	int ykpiv_done(ykpiv_state *state);
+		YKPIV_OK = 0,
+		YKPIV_MEMORY_ERROR = -1,
+		YKPIV_PCSC_ERROR = -2,
+	} ykpiv_rc;
+
+	const char *ykpiv_strerror(ykpiv_rc err);
+	const char *ykpiv_strerror_name(ykpiv_rc err);
+
+	ykpiv_rc ykpiv_init(ykpiv_state **state, int verbose);
+	ykpiv_rc ykpiv_done(ykpiv_state *state);
+	ykpiv_rc ykpiv_connect(ykpiv_state *state, const char *wanted);
+
+
 
 #ifdef __cplusplus
 }

lib/ykpiv.map

@@ -28,6 +28,8 @@ YKPIV_0.1.0
 {
 global:
 	ykpiv_check_version;
+	ykpiv_strerror_name;
+	ykpiv_strerror;
 	ykpiv_init;
 	ykpiv_map;