binutils: Initial implementation of aa-exec in C

Create a simple aa-exec implementation, written in C, matching the
--help, --debug, --verbose, and --profile options present in the current
Perl implementation.

The new aa-exec sources reside in the binutils/ directory.

Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Acked-by: John Johansen <john.johansen@canonical.com>

binutils/Makefile

@@ -50,7 +50,7 @@ EXTRA_CFLAGS+=-DPACKAGE=\"${NAME}\" -DLOCALEDIR=\"${LOCALEDIR}\"
 
 SRCS = aa_enabled.c
 HDRS =
-TOOLS = aa-enabled
+TOOLS = aa-enabled aa-exec
 
 AALIB = -Wl,-Bstatic -lapparmor  -Wl,-Bdynamic -lpthread
 
@@ -106,7 +106,7 @@ all:	arch indep
 
 .PHONY: coverage
 coverage:
-	$(MAKE) clean aa-enabled COVERAGE=1
+	$(MAKE) clean $(TOOLS) COVERAGE=1
 
 ifndef USE_SYSTEM
 $(LIBAPPARMOR_A):
@@ -121,12 +121,15 @@ endif
 aa-enabled: aa_enabled.c $(LIBAPPARMOR_A)
 	$(CC) $(LDFLAGS) $(EXTRA_CFLAGS) -o $@ $< $(LIBS) $(AALIB) 
 
+aa-exec: aa_exec.c $(LIBAPPARMOR_A)
+	$(CC) $(LDFLAGS) $(EXTRA_CFLAGS) -o $@ $< $(LIBS) $(AALIB)
+
 .SILENT: check
 .PHONY: check
 check: check_pod_files tests
 
 .SILENT: tests
-tests: aa-enabled $(TESTS)
+tests: $(TOOLS) $(TESTS)
 	echo "no tests atm"
 
 .PHONY: install

binutils/aa_exec.c

@@ -0,0 +1,167 @@
+/*
+ *   Copyright (c) 2015
+ *   Canonical, Ltd. (All rights reserved)
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of version 2 of the GNU General Public
+ *   License published by the Free Software Foundation.
+ *
+ *   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, contact Novell, Inc. or Canonical
+ *   Ltd.
+ */
+
+#include <errno.h>
+#include <getopt.h>
+#include <libintl.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/apparmor.h>
+#include <unistd.h>
+#define _(s) gettext(s)
+
+static const char *opt_profile = NULL;
+static bool opt_debug = false;
+static bool opt_verbose = false;
+
+static void usage(const char *name, bool error)
+{
+	FILE *stream = stdout;
+	int status = EXIT_SUCCESS;
+
+	if (error) {
+		stream = stderr;
+		status = EXIT_FAILURE;
+	}
+
+	fprintf(stream,
+		_("USAGE: %s [OPTIONS] <prog> <args>\n"
+		"\n"
+		"Confine <prog> with the specified PROFILE.\n"
+		"\n"
+		"OPTIONS:\n"
+		"  -p PROFILE, --profile=PROFILE		PROFILE to confine <prog> with\n"
+		"  -d, --debug				show messages with debugging information\n"
+		"  -v, --verbose				show messages with stats\n"
+		"  -h, --help				display this help\n"
+		"\n"), name);
+	exit(status);
+}
+
+#define error(fmt, args...) _error(_("aa-exec: ERROR: " fmt "\n"), ## args)
+static void _error(const char *fmt, ...)
+{
+	va_list args;
+
+	va_start(args, fmt);
+	vfprintf(stderr, fmt, args);
+	va_end(args);
+	exit(EXIT_FAILURE);
+}
+
+#define debug(fmt, args...) _debug(_("aa-exec: DEBUG: " fmt "\n"), ## args)
+static void _debug(const char *fmt, ...)
+{
+	va_list args;
+
+	if (!opt_debug)
+		return;
+
+	va_start(args, fmt);
+	vfprintf(stderr, fmt, args);
+	va_end(args);
+}
+
+#define verbose(fmt, args...) _verbose(_(fmt "\n"), ## args)
+static void _verbose(const char *fmt, ...)
+{
+	va_list args;
+
+	if (!opt_verbose)
+		return;
+
+	va_start(args, fmt);
+	vfprintf(stderr, fmt, args);
+	va_end(args);
+}
+
+static void verbose_print_argv(char **argv)
+{
+	if (!opt_verbose)
+		return;
+
+	fprintf(stderr, _("exec"));
+	for (; *argv; argv++)
+		fprintf(stderr, " %s", *argv);
+	fprintf(stderr, "\n");
+}
+
+static char **parse_args(int argc, char **argv)
+{
+	int opt;
+	struct option long_opts[] = {
+		{"debug", no_argument, 0, 'd'},
+		{"help", no_argument, 0, 'h'},
+		{"profile", required_argument, 0, 'p'},
+		{"verbose", no_argument, 0, 'v'},
+	};
+
+	while ((opt = getopt_long(argc, argv, "+dhp:v", long_opts, NULL)) != -1) {
+		switch (opt) {
+		case 'd':
+			opt_debug = true;
+			break;
+		case 'h':
+			usage(argv[0], false);
+			break;
+		case 'p':
+			opt_profile = optarg;
+			break;
+		case 'v':
+			opt_verbose = true;
+			break;
+		default:
+			usage(argv[0], true);
+			break;
+		}
+	}
+
+	if (optind >= argc)
+		usage(argv[0], true);
+
+	return argv + optind;
+}
+
+int main(int argc, char **argv)
+{
+	int rc = 0;
+
+	argv = parse_args(argc, argv);
+
+	if (opt_profile) {
+		verbose("aa_change_onexec(\"%s\")", opt_profile);
+		rc = aa_change_onexec(opt_profile);
+		debug("%d = aa_change_onexec(\"%s\")", rc, opt_profile);
+	}
+
+	if (rc) {
+		if (errno == ENOENT || errno == EACCES) {
+			error("profile '%s' does not exist", opt_profile);
+		} else if (errno == EINVAL) {
+			error("AppArmor interface not available");
+		} else {
+			error("%m");
+		}
+	}
+
+	verbose_print_argv(argv);
+	execvp(argv[0], argv);
+	error("Failed to execute \"%s\": %m", argv[0]);
+}