core-agent-linux/qubes-rpc/vm-file-editor.c

#include <sys/stat.h>
#include <sys/wait.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <ioall.h>
#include "dvm2.h"

#define USER_HOME "/home/user"
#define MIMEINFO_DATABASES "/usr/share/mime:/usr/local/share:" USER_HOME "/.local/share:/usr/share/qubes/mime-override"

char *gettime()
{
	static char retbuf[60];
	struct timeval tv;
	gettimeofday(&tv, NULL);
	snprintf(retbuf, sizeof(retbuf), "%lld.%06lld",
		 (long long) tv.tv_sec, (long long) tv.tv_usec);
	return retbuf;
}

char *get_filename()
{
	char buf[DVM_FILENAME_SIZE];
	static char retname[sizeof(buf) + sizeof("/tmp/")];
	int i;
	if (!read_all(0, buf, sizeof(buf)))
		exit(1);
	buf[DVM_FILENAME_SIZE-1] = 0;
	if (index(buf, '/')) {
		fprintf(stderr, "filename contains /");
		exit(1);
	}
	for (i=0; buf[i]!=0; i++) {
		// replace some characters with _ (eg mimeopen have problems with some of them)
		if (index(" !?\"#$%^&*()[]<>;`~", buf[i]))
			buf[i]='_';
	}
	snprintf(retname, sizeof(retname), "/tmp/%s", buf);
	return retname;
}

void copy_file(char *filename)
{
	int fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0600);
	if (fd < 0) {
		perror("open file");
		exit(1);
	}
	if (!copy_fd_all(fd, 0))
        exit(1);
	close(fd);
}

void send_file_back(char * filename)
{
	int fd = open(filename, O_RDONLY);
	if (fd < 0) {
		perror("open file");
		exit(1);
	}
	if (!copy_fd_all(1, fd))
	 exit(1);
	close(fd);
	close(1);
}

int
main()
{
	struct stat stat_pre, stat_post, session_stat;
	char *filename = get_filename();
	int child, status, log_fd, null_fd;
	char var[1024], val[4096];
	FILE *env_file;
	FILE *waiter_pidfile;

	copy_file(filename);
	if (stat(filename, &stat_pre)) {
		perror("stat pre");
		exit(1);
	}
	fprintf(stderr, "time=%s, waiting for qubes-session\n", gettime());
	// wait for X server to starts (especially in DispVM)
	if (stat("/tmp/qubes-session-env", &session_stat)) {
		switch (child = fork()) {
			case -1:
				perror("fork");
				exit(1);
			case 0:
				waiter_pidfile = fopen("/tmp/qubes-session-waiter", "a");
				if (waiter_pidfile == NULL) {
					perror("fopen waiter_pidfile");
					exit(1);
				}
				fprintf(waiter_pidfile, "%d\n", getpid());
				fclose(waiter_pidfile);
				// check the second time, to prevent race
				if (stat("/tmp/qubes-session-env", &session_stat)) {
					// wait for qubes-session notify
					pause();
				}
				exit(0);
			default:
				waitpid(child, &status, 0);
				if (WIFEXITED(status) && WEXITSTATUS(status) != 0) {
					//propagate exit code from child
					exit(WEXITSTATUS(status));
				}
		}
	}
	fprintf(stderr, "time=%s, starting editor\n", gettime());
	switch (child = fork()) {
		case -1:
			perror("fork");
			exit(1);
		case 0:
			null_fd = open("/dev/null", O_RDONLY);
			dup2(null_fd, 0);
			close(null_fd);		

			env_file = fopen("/tmp/qubes-session-env", "r");
			while(fscanf(env_file, "%1024[^=]=%4096[^\n]\n", var, val) == 2) {
				setenv(var, val, 1);
			}
			fclose(env_file);

			log_fd = open("/tmp/mimeopen.log", O_CREAT | O_APPEND, 0666);
			if (log_fd == -1) {
				perror("open /tmp/mimeopen.log");
				exit(1);
			}
			dup2(log_fd, 1);
			close(log_fd);

			setenv("HOME", USER_HOME, 1);
			setenv("DISPLAY", ":0", 1);
			execl("/usr/bin/mimeopen", "mimeopen", "-n",
					"--database", MIMEINFO_DATABASES, filename, (char*)NULL);
			perror("execl");
			exit(1);
		default:
			waitpid(child, &status, 0);
			if (status != 0) {
				char cmd[512];
#ifdef USE_KDIALOG
				snprintf(cmd, sizeof(cmd),
						"HOME=/home/user DISPLAY=:0 /usr/bin/kdialog --sorry 'Unable to handle mimetype of the requested file (exit status: %d)!' > /tmp/kdialog.log 2>&1 </dev/null", status);
					("HOME=/home/user DISPLAY=:0 /usr/bin/kdialog --sorry 'Unable to handle mimetype of the requested file (exit status: %d)!' > /tmp/kdialog.log 2>&1 </dev/null", status);
#else
				snprintf(cmd, sizeof(cmd),
						"HOME=/home/user DISPLAY=:0 /usr/bin/zenity --error --text 'Unable to handle mimetype of the requested file (exit status: %d)!' > /tmp/kdialog.log 2>&1 </dev/null", status);
#endif
				system(cmd);
			}
	}

	if (stat(filename, &stat_post)) {
		perror("stat post");
		exit(1);
	}
	if (stat_pre.st_mtime != stat_post.st_mtime)
		send_file_back(filename);
	return 0;
}