core-agent-linux: misc const fixups

qrexec/qrexec-agent.c

@@ -112,14 +112,14 @@ void no_colon_in_cmd()
 	exit(1);
 }
 
-void do_exec(char *cmd)
+void do_exec(const char *cmd)
 {
 	char buf[strlen(QUBES_RPC_MULTIPLEXER_PATH) + strlen(cmd) - strlen(QUBES_RPC_MAGIC_CMD) + 1];
-	char *realcmd = index(cmd, ':');
+	char *realcmd = index(cmd, ':'), *user;
 	if (!realcmd)
 		no_colon_in_cmd();
 	/* mark end of username and move to command */
-	*realcmd = 0;
+        user=strndup(cmd,realcmd-cmd);
 	realcmd++;
 	/* ignore "nogui:" prefix in linux agent */
 	if (strncmp(realcmd, "nogui:", 6) == 0)
@@ -133,7 +133,7 @@ void do_exec(char *cmd)
 	signal(SIGCHLD, SIG_DFL);
 	signal(SIGPIPE, SIG_DFL);
 
-	execl("/bin/su", "su", "-", cmd, "-c", realcmd, NULL);
+	execl("/bin/su", "su", "-", user, "-c", realcmd, NULL);
 	perror("execl");
 	exit(1);
 }

qubes-rpc/ioall.c

@@ -25,7 +25,7 @@
 #include <fcntl.h>
 #include <errno.h>
 
-void perror_wrapper(char * msg)
+void perror_wrapper(const char * msg)
 {
 	int prev=errno;
 	perror(msg);
@@ -48,7 +48,7 @@ void set_block(int fd)
 	fcntl(fd, F_SETFL, fl & ~O_NONBLOCK);
 }
 
-int write_all(int fd, void *buf, int size)
+int write_all(int fd, const void *buf, int size)
 {
 	int written = 0;
 	int ret;

qubes-rpc/qfile-unpacker.c

@@ -12,7 +12,7 @@
 #include <errno.h>
 #include <libqubes-rpc-filecopy.h>
 #define INCOMING_DIR_ROOT "/home/user/QubesIncoming"
-int prepare_creds_return_uid(char *username)
+int prepare_creds_return_uid(const char *username)
 {
 	struct passwd *pwd;
 	pwd = getpwnam(username);
@@ -37,7 +37,7 @@ int main(int argc, char ** argv)
 {
 	char *incoming_dir;
 	int uid;
-	char *remote_domain;
+	const char *remote_domain;
 
 	uid = prepare_creds_return_uid("user");