Added qfile-agent-dvm.c

Nations, rejoice.

appvm/Makefile

@@ -1,8 +1,10 @@
 CC=gcc
 CFLAGS=-Wall -I../common
-all:	qubes_penctl qubes_add_pendrive_script qvm-open-in-dvm dvm_file_editor
+all:	qubes_penctl qubes_add_pendrive_script qvm-open-in-dvm dvm_file_editor qfile-agent-dvm
 dvm_file_editor: dvm_file_editor.o ../common/ioall.o
 	$(CC) -o dvm_file_editor dvm_file_editor.o ../common/ioall.o
+qfile-agent-dvm: qfile-agent-dvm.o ../common/ioall.o
+	$(CC) -o qfile-agent-dvm qfile-agent-dvm.o ../common/ioall.o
 qubes_penctl: qubes_penctl.o
 	$(CC) -o qubes_penctl qubes_penctl.o -lxenstore
 qubes_add_pendrive_script: qubes_add_pendrive_script.o

appvm/qfile-agent-dvm.c

@@ -0,0 +1,156 @@
+#define _GNU_SOURCE
+#include <dirent.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <signal.h>
+#include <fcntl.h>
+#include <malloc.h>
+#include <stdlib.h>
+#include <ioall.h>
+#include <unistd.h>
+#include "dvm2.h"
+
+//the below usage of "system" is smelly, but should be fine - input comes from the same vm
+void fatal(char *msg)
+{
+	char *errcmd;
+	asprintf(&errcmd, "DISPLAY=:0 kdialog --sorry 'qfile-agent-dvm: %s'", msg);
+	system(errcmd);
+	perror(msg);
+	exit(1);
+}
+
+void nonfatal(char *msg)
+{
+	char *errcmd;
+	asprintf(&errcmd, "DISPLAY=:0 kdialog --sorry 'qfile-agent-dvm: %s'", msg);
+	system(errcmd);
+	fprintf(stderr, "%s", msg);
+}
+
+void send_file(char *fname)
+{
+	char *base;
+	int fd = open(fname, O_RDONLY);
+	if (fd < 0)
+		fatal("open file_to_be_edited");
+	base = rindex(fname, '/');
+	if (!base)
+		base = fname;
+	else
+		base++;
+	if (strlen(base) >= DVM_FILENAME_SIZE)
+		base += strlen(base) - DVM_FILENAME_SIZE + 1;
+	if (!write_all(1, base, DVM_FILENAME_SIZE))
+		fatal("send filename");
+	if (!copy_fd_all(1, fd))
+		fatal("send file");
+	close(1);
+}
+
+int copy_and_return_nonemptiness(int tmpfd)
+{
+	struct stat st;
+	if (!copy_fd_all(tmpfd, 0))
+		fatal("receiving file");
+	if (fstat(tmpfd, &st))
+		fatal("fstat");
+	close(tmpfd);
+
+	return st.st_size;
+}
+
+void recv_file_nowrite(char *fname)
+{
+	char *tempfile;
+	char *errmsg;
+	int tmpfd;
+
+	asprintf(&tempfile, "/tmp/file_edited_in_dvm.XXXXXX");
+	tmpfd = mkstemp(tempfile);
+	if (tmpfd < 0)
+		fatal("unable to create any temporary file, aborting");
+	if (!copy_and_return_nonemptiness(tmpfd)) {
+		unlink(tempfile);
+		return;
+	}
+	asprintf(&errmsg,
+		 "The file %s has been edited in Disposable VM and the modified content has been received, "
+		 "but this file is in nonwritable directory and thus cannot be modified safely. The edited file has been "
+		 "saved to %s", fname, tempfile);
+	nonfatal(errmsg);
+}
+
+void actually_recv_file(char *fname, char *tempfile, int tmpfd)
+{
+	if (!copy_and_return_nonemptiness(tmpfd)) {
+		unlink(tempfile);
+		return;
+	}
+	if (rename(tempfile, fname))
+		fatal("rename");
+}
+
+void recv_file(char *fname)
+{
+	int tmpfd;
+	char *tempfile;
+	asprintf(&tempfile, "%s.XXXXXX", fname);
+	tmpfd = mkstemp(tempfile);
+	if (tmpfd < 0)
+		recv_file_nowrite(fname);
+	else
+		actually_recv_file(fname, tempfile, tmpfd);
+}
+
+void talk_to_daemon(char *fname)
+{
+	send_file(fname);
+	recv_file(fname);
+}
+
+void process_spoolentry(char *entry_name)
+{
+	char *abs_spool_entry_name;
+	int entry_fd;
+	struct stat st;
+	char *filename;
+	int entry_size;
+	asprintf(&abs_spool_entry_name, "%s/%s", DVM_SPOOL, entry_name);
+	entry_fd = open(abs_spool_entry_name, O_RDONLY);
+	unlink(abs_spool_entry_name);
+	if (entry_fd < 0 || fstat(entry_fd, &st))
+		fatal("bad dvm_entry");
+	entry_size = st.st_size;
+	filename = calloc(1, entry_size + DVM_FILENAME_SIZE);
+	if (!filename)
+		fatal("malloc");
+	if (!read_all(entry_fd, filename, entry_size))
+		fatal("read dvm entry");
+	close(entry_fd);
+	talk_to_daemon(filename);
+}
+
+void scan_spool(char *name)
+{
+	struct dirent *ent;
+	DIR *dir = opendir(name);
+	if (!dir)
+		fatal("opendir");
+	while ((ent = readdir(dir))) {
+		char *fname = ent->d_name;
+		if (!strcmp(fname, ".") || !strcmp(fname, ".."))
+			continue;
+		process_spoolentry(fname);
+		break;
+	}
+	closedir(dir);
+}
+
+int main()
+{
+	signal(SIGPIPE, SIG_IGN);
+	scan_spool(DVM_SPOOL);
+	return 0;
+}