service: add workdir support for daemon instances

jail/jail.c

@@ -102,7 +102,7 @@
 #define PR_MDWE_NO_INHERIT (1UL << 1)
 #endif
 
-#define OPT_ARGS	"a:A:b:cC:d:De:EfFG:h:iI:j:J:k:lm:M:n:NoO:pP:r:R:sS:uU:V:w:x:t:T:yY:Z"
+#define OPT_ARGS	"a:A:b:cC:d:De:EfFG:h:iI:j:J:k:lm:M:n:NoO:pP:r:R:sS:uU:V:w:W:x:t:T:yY:Z"
 
 #define JAIL_MAX_CREDENTIALS	16
 static const char *cred_targets[JAIL_MAX_CREDENTIALS];
@@ -2464,6 +2464,7 @@ static void usage(void)
 	fprintf(stderr, "  -n <name>\tthe name of the jail\n");
 	fprintf(stderr, "  -e <var>\timport environment variable\n");
 	fprintf(stderr, "  -x <file>\tappend KEY=VALUE lines from <file> to the container env\n");
+	fprintf(stderr, "  -W <dir>\tworking directory for the jailed process\n");
 	fprintf(stderr, "namespace jail options:\n");
 	fprintf(stderr, "  -h <hostname>\tchange the hostname of the jail\n");
 	fprintf(stderr, "  -N\t\tjail has network namespace\n");
@@ -4084,8 +4085,10 @@ static int parseOCIprocess(struct blob_attr *msg)
 	if (tb[OCI_PROCESS_NONEWPRIVILEGES])
 		opts.no_new_privs = blobmsg_get_bool(tb[OCI_PROCESS_NONEWPRIVILEGES]);
 
-	if (tb[OCI_PROCESS_CWD])
+	if (tb[OCI_PROCESS_CWD]) {
+		free(opts.cwd);
 		opts.cwd = strdup(blobmsg_get_string(tb[OCI_PROCESS_CWD]));
+	}
 
 	if (tb[OCI_PROCESS_ENV]) {
 		res = parseOCIenvarray(tb[OCI_PROCESS_ENV], &opts.envp);
@@ -6841,6 +6844,12 @@ int main(int argc, char **argv)
 		case 'G':
 			opts.group = optarg;
 			break;
+		case 'W':
+			free(opts.cwd);
+			opts.cwd = strdup(optarg);
+			if (!opts.cwd)
+				free_and_exit(EXIT_FAILURE);
+			break;
 		case 'O':
 			opts.overlaydir = realpath(optarg, NULL);
 			break;

service/instance.c

@@ -46,6 +46,7 @@
 
 enum {
 	INSTANCE_ATTR_COMMAND,
+	INSTANCE_ATTR_WORKDIR,
 	INSTANCE_ATTR_ENV,
 	INSTANCE_ATTR_DATA,
 	INSTANCE_ATTR_NETDEV,
@@ -81,6 +82,7 @@ enum {
 
 static const struct blobmsg_policy instance_attr[__INSTANCE_ATTR_MAX] = {
 	[INSTANCE_ATTR_COMMAND] = { "command", BLOBMSG_TYPE_ARRAY },
+	[INSTANCE_ATTR_WORKDIR] = { "workdir", BLOBMSG_TYPE_STRING },
 	[INSTANCE_ATTR_ENV] = { "env", BLOBMSG_TYPE_TABLE },
 	[INSTANCE_ATTR_DATA] = { "data", BLOBMSG_TYPE_TABLE },
 	[INSTANCE_ATTR_NETDEV] = { "netdev", BLOBMSG_TYPE_ARRAY },
@@ -359,6 +361,11 @@ jail_run(struct service_instance *in, char **argv)
 		argv[argc++] = in->group;
 	}
 
+	if (in->workdir) {
+		argv[argc++] = "-W";
+		argv[argc++] = in->workdir;
+	}
+
 	if (in->capabilities) {
 		argv[argc++] = "-C";
 		argv[argc++] = in->capabilities;
@@ -632,6 +639,12 @@ instance_run(struct service_instance *in, int _stdout, int _stderr)
 		exit(127);
 	}
 
+	if (!in->has_jail && in->workdir && chdir(in->workdir)) {
+		ERROR("failed to change directory to %s for %s::%s: %m\n",
+		      in->workdir, in->srv->name, in->name);
+		exit(127);
+	}
+
 	execvp(argv[0], argv);
 	exit(127);
 }
@@ -1279,6 +1292,9 @@ instance_config_changed(struct service_instance *in, struct service_instance *in
 	if (!blob_attr_equal(in->command, in_new->command))
 		return true;
 
+	if (string_changed(in->workdir, in_new->workdir))
+		return true;
+
 	if (string_changed(in->bundle, in_new->bundle))
 		return true;
 
@@ -1622,6 +1638,9 @@ instance_jail_parse(struct service_instance *in, struct blob_attr *attr)
 	if (in->group)
 		jail->argc += 2;
 
+	if (in->workdir)
+		jail->argc += 2;
+
 	if (in->extroot)
 		jail->argc += 2;
 
@@ -1736,6 +1755,12 @@ instance_config_parse(struct service_instance *in)
 		}
 	}
 
+	if (tb[INSTANCE_ATTR_WORKDIR]) {
+		in->workdir = strdup(blobmsg_get_string(tb[INSTANCE_ATTR_WORKDIR]));
+		if (!in->workdir)
+			return false;
+	}
+
 	if (tb[INSTANCE_ATTR_TRACE])
 		in->trace = blobmsg_get_bool(tb[INSTANCE_ATTR_TRACE]);
 
@@ -1934,6 +1959,7 @@ instance_config_move(struct service_instance *in, struct service_instance *in_sr
 	instance_config_move_strdup(&in->tmpoverlaysize, in_src->tmpoverlaysize);
 	instance_config_move_strdup(&in->user, in_src->user);
 	instance_config_move_strdup(&in->group, in_src->group);
+	instance_config_move_strdup(&in->workdir, in_src->workdir);
 	instance_config_move_strdup(&in->jail.name, in_src->jail.name);
 	instance_config_move_strdup(&in->jail.hostname, in_src->jail.hostname);
 	instance_config_move_strdup(&in->jail.pidfile, in_src->jail.pidfile);
@@ -2041,6 +2067,7 @@ instance_free(struct service_instance *in)
 	free(in->data_blob);
 	free(in->user);
 	free(in->group);
+	free(in->workdir);
 	free(in->extroot);
 	free(in->overlaydir);
 	free(in->tmpoverlaysize);
@@ -2126,6 +2153,8 @@ void instance_dump(struct blob_buf *b, struct service_instance *in, int verbose)
 		blobmsg_add_u64(b, "incarnation", in->incarnation);
 	if (in->command)
 		blobmsg_add_blob(b, in->command);
+	if (in->workdir)
+		blobmsg_add_string(b, "workdir", in->workdir);
 	if (in->bundle)
 		blobmsg_add_string(b, "bundle", in->bundle);
 	blobmsg_add_u32(b, "term_timeout", in->term_timeout);

service/instance.h

@@ -99,6 +99,7 @@ struct service_instance {
 	char *seccomp_log;
 	char *capabilities;
 	char *pidfile;
+	char *workdir;
 	char *extroot;
 	char *overlaydir;
 	char *tmpoverlaysize;