From 5714dbfa08cd5f77312d5dbcb06012ff992ed450 Mon Sep 17 00:00:00 2001
From: Peter Marschall <peter@adpm.de>
Date: Sun, 12 Jan 2020 10:40:05 +0100
Subject: [PATCH] opensc-explorer: add function 'get_record'

---
 doc/tools/opensc-explorer.1.xml | 25 +++++++++
 src/tools/opensc-explorer.c     | 90 +++++++++++++++++++++++++++++++++
 2 files changed, 115 insertions(+)

diff --git a/doc/tools/opensc-explorer.1.xml b/doc/tools/opensc-explorer.1.xml
index 30bc3057..8632f8de 100644
--- a/doc/tools/opensc-explorer.1.xml
+++ b/doc/tools/opensc-explorer.1.xml
@@ -403,6 +403,31 @@
 					</listitem>
 				</varlistentry>
 
+				<varlistentry>
+					<term>
+						<command>get_record</command>
+						<replaceable>file-id</replaceable>
+						<replaceable>rec-no</replaceable>
+						<arg choice="opt"><replaceable>output</replaceable></arg>
+					</term>
+					<listitem>
+						<para>
+							Copy a record of a record-oriented EF to a local file.
+							The local file is specified by
+							<replaceable>output</replaceable>
+							while the card file and the record are specified by
+							<replaceable>file-id</replaceable> and
+							<replaceable>rec-no</replaceable>,
+						</para>
+						<para>
+							If <replaceable>output</replaceable> is omitted,
+							the name of the output file will be derived from the
+							full card path to <replaceable>file-id</replaceable>.
+							and the <replaceable>rec-no</replaceable>.
+						</para>
+					</listitem>
+				</varlistentry>
+
 				<varlistentry>
 					<term>
 						<command>help</command>
diff --git a/src/tools/opensc-explorer.c b/src/tools/opensc-explorer.c
index 16ef9d17..d2c7d5ca 100644
--- a/src/tools/opensc-explorer.c
+++ b/src/tools/opensc-explorer.c
@@ -100,6 +100,7 @@ static int do_verify(int argc, char **argv);
 static int do_change(int argc, char **argv);
 static int do_unblock(int argc, char **argv);
 static int do_get(int argc, char **argv);
+static int do_get_record(int argc, char **argv);
 static int do_update_binary(int argc, char **argv);
 static int do_update_record(int argc, char **argv);
 static int do_put(int argc, char **argv);
@@ -174,6 +175,9 @@ static struct command	cmds[] = {
 	{ do_get,
 		"get",	"<file-id> [<output-file>]",
 		"copy an EF to a local file"		},
+	{ do_get_record,
+		"get_record",	"<file-id> <rec-no> [<output-file>]",
+		"copy a record of an EF to a local file"	},
 	{ do_get_data,
 		"do_get",	"<hex-tag> [<output-file>]",
 		"get a data object"			},
@@ -1474,6 +1478,92 @@ err:
 	return -err;
 }
 
+static int do_get_record(int argc, char **argv)
+{
+	u8 buf[SC_MAX_EXT_APDU_RESP_SIZE];
+	int r, err = 1;
+	size_t rec, count = 0;
+	sc_path_t path;
+	sc_file_t *file = NULL;
+	char *filename;
+	FILE *outf = NULL;
+
+	if (argc < 2 || argc > 3)
+		return usage(do_get);
+	if (arg_to_path(argv[0], &path, 0) != 0)
+		return usage(do_get);
+	rec = strtoul(argv[1], NULL, 10);
+
+	filename = (argc == 3) ? argv[2] : path_to_filename(&path, '_', rec);
+	outf = (strcmp(filename, "-") == 0)
+		? stdout
+		: fopen(filename, "wb");
+	if (outf == NULL) {
+		perror(filename);
+		goto err;
+	}
+
+	r = sc_lock(card);
+	if (r == SC_SUCCESS)
+		r = sc_select_file(card, &path, &file);
+	sc_unlock(card);
+	if (r || file == NULL) {
+		check_ret(r, SC_AC_OP_SELECT, "Unable to select file", current_file);
+		goto err;
+	}
+
+	/* fail on wrong file type */
+	if (file->type != SC_FILE_TYPE_WORKING_EF ||
+		(file->ef_structure != SC_FILE_EF_LINEAR_FIXED &&
+		file->ef_structure != SC_FILE_EF_LINEAR_FIXED_TLV &&
+		file->ef_structure != SC_FILE_EF_LINEAR_VARIABLE &&
+		file->ef_structure != SC_FILE_EF_LINEAR_VARIABLE_TLV)) {
+		fprintf(stderr, "Only record-oriented working EFs may be read\n");
+		goto err;
+	}
+
+	/* fail on out of bound record index:
+	 * must be > 0 and if record_count is set <= record_count */
+	if (rec < 1 || (file->record_count > 0 && rec > file->record_count)) {
+		fprintf(stderr, "Invalid record number %"SC_FORMAT_LEN_SIZE_T"u\n", rec);
+		goto err;
+	}
+
+	r = sc_read_record(card, rec, buf, sizeof(buf), SC_RECORD_BY_REC_NR);
+	if (r < 0)   {
+		fprintf(stderr, "Cannot read record %"SC_FORMAT_LEN_SIZE_T"u; return %i\n", rec, r);
+		goto err;
+	}
+
+	count = r;
+
+	if (count > 0) {
+		size_t written = fwrite(buf, 1, (size_t) r, outf);
+
+		if (written != count) {
+			fprintf(stderr, "Cannot write to file %s (only %"SC_FORMAT_LEN_SIZE_T"u of %"SC_FORMAT_LEN_SIZE_T"u bytes written)",
+				filename, written, count);
+			goto err;
+		}
+	}
+
+	if (outf == stdout) {
+		fwrite("\n", 1, 1, outf);
+	}
+	else {
+		printf("Total of %"SC_FORMAT_LEN_SIZE_T"u bytes read from %s and saved to %s.\n",
+		       count, argv[0], filename);
+	}
+
+	err = 0;
+err:
+	sc_file_free(file);
+	if (outf != NULL && outf != stdout)
+		fclose(outf);
+	select_current_path_or_die();
+	return -err;
+}
+
 static int do_update_binary(int argc, char **argv)
 {
 	u8 buf[SC_MAX_EXT_APDU_DATA_SIZE];