qemu-start/trunk/qemu-start.c

/*
    qemu-start.c - Part of qemu-start, a package to start qemu nicely.
    Copyright (c) 2006  Frodo Looijaard <frodo@frodo.looijaard.name>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    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, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#define _GNU_SOURCE /* asprintf */
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <pwd.h>
#include <grp.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <net/if.h>
#include <linux/if_tun.h>
#include <sys/wait.h>
#include <errno.h>

/* Autogenerated by gengetopt */
#include "cmdline.h"

/* This define is present in recent glibc, it is not available on sarge */
#ifndef HOST_NAME_MAX
#define HOST_NAME_MAX 64
#endif

#define QEMU "/usr/bin/qemu"
#define USER "qemu"

/* 
 * This function merges the xauthority data of the current X context
 * into the QEMU user's .Xauthority file.
 */
void fix_xauthority(void) {
        struct passwd *userdata;
        int pfd[2];
        char *xauthfile;
        char *display;
        char *newdisplay;
        char *hostname;
//      int status1, status2;
        int status,pid;
        pid_t cpid1, cpid2;

        if (pipe(pfd)) {
                perror("pipe failed");
                exit(1);
        }

        cpid1 = fork();
        if (cpid1 < 0) {
                perror("first fork failed");
                exit(1);
        }

        /* Child: will execute the xauth extract */
        if (cpid1 == 0) {
                /* Child may run as original process starter */
                if (setgroups(0, NULL)) {
                        perror("setgroups failed");
                        exit(1);
                }
                if (setgid(getgid())) {
                        perror("setgid failed");
                        exit(1);
                }
                if (setuid(getuid())) {
                        perror("setuid failed");
                        exit(1);
                }

                /* Write side of pipe corresponds to stdout */
                if (dup2(pfd[1],1) < 0) {
                        perror("dup2 failed");
                        exit(1);
                }
                if (close(pfd[0])) {
                        perror("close of pfd[0] failed");
                        exit(1);
                }
                if (close(pfd[1])) {
                        perror("close of pfd[1] failed");
                        exit(1);
                }
                
                userdata = getpwuid(getuid());
                if (!userdata) {
                        fprintf(stderr, "No user '%s'\n", USER);
                        exit(1);
                }


                /* Get xauthority file to use */
                if (! (xauthfile = getenv("XAUTHORITY"))) {
                        if (asprintf(&xauthfile,"%s/.Xauthority",userdata->pw_dir) < 1) {
                                perror("Constructing xauthority filename failed");
                                exit(1);
                        }
                }

                /* Get display */
                if (! (display = getenv("DISPLAY"))) {
                        perror("No DISPLAY variable found\n");
                        exit(1);
                }

                /* Substitution: if display starts with `localhost', substitute 
                   `localhost' by `HOSTNAME/unix'. */
                if (strstr(display,"localhost") == display) {
                        hostname = malloc(HOST_NAME_MAX+1);
                        if (gethostname(hostname,HOST_NAME_MAX+1)) {
                                perror("Getting hostname failed");
                                exit(1);
                        }

                        if (!(newdisplay = malloc(strlen(hostname) + 5 + strlen(display)-9 + 1))) {
                                perror("Allocating new display failed");
                                exit(1);
                        }
                        strcpy(newdisplay,hostname);
                        strcpy(newdisplay + strlen(hostname),"/unix");
                        strcpy(newdisplay + strlen(hostname) + 5, display + 9);
                        display = newdisplay;
                } else if (! (display = strdup(display))) {
                        perror("strdup DISPLAY failed");
                        exit(1);
                }

                execl("/usr/bin/X11/xauth","/usr/bin/X11/xauth","-f",xauthfile,"extract","-",display,NULL);
                exit(1);
        }


        cpid2 = fork();
        if (cpid2 < 0) {
                perror("second fork failed");
                exit(1);
        }

        /* Child: will execute the xauth merge */
        if (cpid2 == 0) {
                /* Get userid data. */
                userdata = getpwnam(USER);
                if (!userdata) {
                        fprintf(stderr, "No user '%s'\n", USER);
                        exit(1);
                }

                if (setgroups(0, NULL)) {
                        perror("setgroups failed");
                        exit(1);
                }
                 
                /* Child may run as qemu user */
                if (setgid(userdata->pw_gid)) {
                        perror("setgid failed");
                        exit(1);
                }
                if (setuid(userdata->pw_uid)) {
                        perror("setuid failed");
                        exit(1);
                }
                /* Read side of pipe is stdin */
                if (dup2(pfd[0],0) < 0) {
                        perror("dup2 failed");
                        exit(1);
                }
                if (close(pfd[0])) {
                        perror("close of pfd[0] failed");
                        exit(1);
                }
                if (close(pfd[1])) {
                        perror("close of pfd[1] failed");
                        exit(1);
                }

                if (asprintf(&xauthfile,"%s/.Xauthority",userdata->pw_dir) < 1) {
                        perror("Constructing xauthority filename failed");
                        exit(1);
                }

                execl("/usr/bin/X11/xauth","/usr/bin/X11/xauth","-f",xauthfile,"merge","-",NULL);
                exit(1);
        }

        if (close(pfd[0])) {
                perror("close of pfd[0] failed");
                exit(1);
        }
        if (close(pfd[1])) {
                perror("close of pfd[1] failed");
                exit(1);
        }

        while(1) {
        
                pid = wait(&status);
                if ((pid < 1) && (errno == ECHILD))
                        break;
                if (pid < 1) {
                        perror("wait failed");
                        exit(1);
                }
                if (! WIFEXITED(status) || WEXITSTATUS(status)) {
                        fprintf(stderr,"Child returned error\n");
                        exit(1);
                }
        }
}


/* Tiny code to open tap/tun device, and hand the fd to qemu.
   Run as root, drops to given user. */
int main(int argc, char *argv[])
{
        struct ifreq ifr;
        struct passwd *userdata;
        char *newargs[argc + 2];
        int fd,vlan,tapnr;
        unsigned int i;
        unsigned new_arg_count = 5;
        struct gengetopt_args_info args_info;
        char *display;
        char *system;
        char *topleft;

        /* Ugly fix because gengetopt 2.18 does not have the `usage' option */
        gengetopt_args_info_usage = "qemu-start [OPTIONS] -- [OPTIONS for QEMU]";

        if (cmdline_parser(argc, argv, &args_info))
                exit(1);

        /* parameter: TAPDEVNR */
        tapnr = args_info.tapnr_arg;

        /* parameter: VLAN */
        vlan = args_info.vlan_arg;

        /* parameter: System type */
        if (args_info.system_given) {
                if (index(args_info.system_arg,'/')) {
                        fprintf(stderr, "Invalid value `%s' for system (may not contain a slash character)\n", args_info.system_arg);
                        exit(1);
                }
                asprintf(&system, "%s", args_info.system_arg);
        }

        /* parameters: Window location */
        if (args_info.window_left_given || args_info.window_top_given) {
                if (!(args_info.window_left_given && args_info.window_top_given)) {
                        fprintf(stderr,("If either window-left (x) or window-top (y) are given, then both must be given\n"));
                        exit(1);
                }
                if (asprintf(&topleft, "%d,%d",args_info.window_left_arg,args_info.window_top_arg) < 0) {
                        perror("Preparing top-left environment value string failed");
                        exit(1);
                }
        }

        /* Export the xauth data */
        fix_xauthority();

        /* Open /dev/net/tun */
        fd = open("/dev/net/tun", O_RDWR);
        if (fd < 0) {
                perror("Could not open /dev/net/tun");
                exit(1);
        }

        /* Bind to the right tap device */
        memset(&ifr, 0, sizeof(ifr));
        ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
        snprintf(ifr.ifr_name,IFNAMSIZ,"tap%d",tapnr);

        if (ioctl(fd, TUNSETIFF, (void *) &ifr) != 0) {
                perror("Could not get tap device");
                exit(1);
        }

        /* Get userid data. */
        userdata = getpwnam(USER);
        if (!userdata) {
                fprintf(stderr, "No user '%s'\n", USER);
                exit(1);
        }

        /* Change to QEMU user */
        if (setgroups(0, NULL)) {
                perror("setgroups failed");
                exit(1);
        }
        if (setgid(userdata->pw_gid)) {
                perror("setgid failed");
                exit(1);
        }
        if (setuid(userdata->pw_uid)) {
                perror("setuid failed");
                exit(1);
        }

        /* Clean the environment */
        if(!(display=getenv("DISPLAY"))) {
                perror("Getting DISPLAY failed");
                exit(1);
        }
        if(clearenv()) {
                perror("Clearing environment failed");
                exit(1);
        }
        if(setenv("HOME",userdata->pw_dir,1) ||
           setenv("DISPLAY",display,1) ||
           setenv("PATH","/usr/bin:/bin:/usr/local/bin",1) ||
           setenv("LOGNAME",userdata->pw_name,1) ||
           setenv("USER",userdata->pw_name,1)) {
                perror("Setting environment failed");
                exit(1);
        }
        if (args_info.window_left_given || args_info.window_top_given) {
                if (setenv("SDL_VIDEO_WINDOW_POS", topleft, 1)) {
                        perror("Setting top-left environment value failed");
                        exit(1);
                }
        }

        /* Create the right qemu invocation */
        if (!args_info.system_given)
                newargs[0] = QEMU;
        else if (asprintf(&newargs[0],"%s-system-%s",QEMU,args_info.system_arg) < 0) {
                perror("Preparing qemu executable filename failed");
                exit(1);
        }
        newargs[1] = "-net";
        if (asprintf(&newargs[2],"nic,vlan=%d",vlan) < 0) {
                perror("Preparing nic argument failed");
                exit(1);
        }
        if (args_info.macaddr_given) {
                if (asprintf(&newargs[2], "%s,mac=%s", newargs[2], args_info.macaddr_arg) < 0) {
                        perror("Adding macaddress to nic argument failed");
                }
        }
        if (args_info.nic_model_given) {
                if (asprintf(&newargs[2], "%s,model=%s", newargs[2], args_info.nic_model_arg) < 0) {
                        perror("Adding nic model to nic argument failed");
                }
        }
        newargs[3] = "-net";
        if (asprintf(&newargs[4],"tap,fd=%d,vlan=%d",fd,vlan) < 0) {
                perror("Preparing tap argument failed");
                exit(1);
        }
        for (i = 0; i < args_info.inputs_num; i++) {
                newargs[i+5] = args_info.inputs[i];
                new_arg_count++;
        }
        newargs[new_arg_count] = NULL;

        execvp(newargs[0], newargs);
        perror("Execution of qemu failed");
        exit(1);
}
1	frodo	290	/*
2			qemu-start.c - Part of qemu-start, a package to start qemu nicely.
3			Copyright (c) 2006 Frodo Looijaard <frodo@frodo.looijaard.name>
4
5			This program is free software; you can redistribute it and/or modify
6			it under the terms of the GNU General Public License as published by
7			the Free Software Foundation; either version 2 of the License, or
8			(at your option) any later version.
9
10			This program is distributed in the hope that it will be useful,
11			but WITHOUT ANY WARRANTY; without even the implied warranty of
12			MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13			GNU General Public License for more details.
14
15			You should have received a copy of the GNU General Public License
16			along with this program; if not, write to the Free Software
17			Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18			*/
19
20			#define _GNU_SOURCE /* asprintf */
21			#include <stdio.h>
22			#include <string.h>
23			#include <sys/types.h>
24			#include <pwd.h>
25			#include <grp.h>
26			#include <sys/stat.h>
27			#include <sys/ioctl.h>
28			#include <fcntl.h>
29			#include <unistd.h>
30			#include <stdlib.h>
31			#include <net/if.h>
32			#include <linux/if_tun.h>
33	frodo	295	#include <sys/wait.h>
34			#include <errno.h>
35	frodo	290
36	frodo	314	/* Autogenerated by gengetopt */
37			#include "cmdline.h"
38
39	frodo	295	/* This define is present in recent glibc, it is not available on sarge */
40			#ifndef HOST_NAME_MAX
41			#define HOST_NAME_MAX 64
42			#endif
43
44	frodo	290	#define QEMU "/usr/bin/qemu"
45			#define USER "qemu"
46
47	frodo	295	/*
48			* This function merges the xauthority data of the current X context
49			* into the QEMU user's .Xauthority file.
50			*/
51			void fix_xauthority(void) {
52			struct passwd *userdata;
53			int pfd[2];
54			char *xauthfile;
55			char *display;
56			char *newdisplay;
57			char *hostname;
58			// int status1, status2;
59			int status,pid;
60			pid_t cpid1, cpid2;
61
62			if (pipe(pfd)) {
63			perror("pipe failed");
64			exit(1);
65			}
66
67			cpid1 = fork();
68			if (cpid1 < 0) {
69			perror("first fork failed");
70			exit(1);
71			}
72
73			/* Child: will execute the xauth extract */
74			if (cpid1 == 0) {
75			/* Child may run as original process starter */
76			if (setgroups(0, NULL)) {
77			perror("setgroups failed");
78			exit(1);
79			}
80			if (setgid(getgid())) {
81			perror("setgid failed");
82			exit(1);
83			}
84			if (setuid(getuid())) {
85			perror("setuid failed");
86			exit(1);
87			}
88
89			/* Write side of pipe corresponds to stdout */
90			if (dup2(pfd[1],1) < 0) {
91			perror("dup2 failed");
92			exit(1);
93			}
94			if (close(pfd[0])) {
95			perror("close of pfd[0] failed");
96			exit(1);
97			}
98			if (close(pfd[1])) {
99			perror("close of pfd[1] failed");
100			exit(1);
101			}
102
103			userdata = getpwuid(getuid());
104			if (!userdata) {
105			fprintf(stderr, "No user '%s'\n", USER);
106			exit(1);
107			}
108
109
110			/* Get xauthority file to use */
111			if (! (xauthfile = getenv("XAUTHORITY"))) {
112			if (asprintf(&xauthfile,"%s/.Xauthority",userdata->pw_dir) < 1) {
113			perror("Constructing xauthority filename failed");
114			exit(1);
115			}
116			}
117
118			/* Get display */
119			if (! (display = getenv("DISPLAY"))) {
120			perror("No DISPLAY variable found\n");
121			exit(1);
122			}
123
124			/* Substitution: if display starts with `localhost', substitute
125			`localhost' by `HOSTNAME/unix'. */
126			if (strstr(display,"localhost") == display) {
127			hostname = malloc(HOST_NAME_MAX+1);
128			if (gethostname(hostname,HOST_NAME_MAX+1)) {
129			perror("Getting hostname failed");
130			exit(1);
131			}
132
133			if (!(newdisplay = malloc(strlen(hostname) + 5 + strlen(display)-9 + 1))) {
134			perror("Allocating new display failed");
135			exit(1);
136			}
137			strcpy(newdisplay,hostname);
138			strcpy(newdisplay + strlen(hostname),"/unix");
139			strcpy(newdisplay + strlen(hostname) + 5, display + 9);
140			display = newdisplay;
141			} else if (! (display = strdup(display))) {
142			perror("strdup DISPLAY failed");
143			exit(1);
144			}
145
146			execl("/usr/bin/X11/xauth","/usr/bin/X11/xauth","-f",xauthfile,"extract","-",display,NULL);
147			exit(1);
148			}
149
150
151			cpid2 = fork();
152			if (cpid2 < 0) {
153			perror("second fork failed");
154			exit(1);
155			}
156
157			/* Child: will execute the xauth merge */
158			if (cpid2 == 0) {
159			/* Get userid data. */
160			userdata = getpwnam(USER);
161			if (!userdata) {
162			fprintf(stderr, "No user '%s'\n", USER);
163			exit(1);
164			}
165
166			if (setgroups(0, NULL)) {
167			perror("setgroups failed");
168			exit(1);
169			}
170
171			/* Child may run as qemu user */
172			if (setgid(userdata->pw_gid)) {
173			perror("setgid failed");
174			exit(1);
175			}
176			if (setuid(userdata->pw_uid)) {
177			perror("setuid failed");
178			exit(1);
179			}
180			/* Read side of pipe is stdin */
181			if (dup2(pfd[0],0) < 0) {
182			perror("dup2 failed");
183			exit(1);
184			}
185			if (close(pfd[0])) {
186			perror("close of pfd[0] failed");
187			exit(1);
188			}
189			if (close(pfd[1])) {
190			perror("close of pfd[1] failed");
191			exit(1);
192			}
193
194			if (asprintf(&xauthfile,"%s/.Xauthority",userdata->pw_dir) < 1) {
195	frodo	314	perror("Constructing xauthority filename failed");
196	frodo	295	exit(1);
197			}
198
199			execl("/usr/bin/X11/xauth","/usr/bin/X11/xauth","-f",xauthfile,"merge","-",NULL);
200			exit(1);
201			}
202
203			if (close(pfd[0])) {
204			perror("close of pfd[0] failed");
205			exit(1);
206			}
207			if (close(pfd[1])) {
208			perror("close of pfd[1] failed");
209			exit(1);
210			}
211
212			while(1) {
213
214			pid = wait(&status);
215			if ((pid < 1) && (errno == ECHILD))
216			break;
217			if (pid < 1) {
218			perror("wait failed");
219			exit(1);
220			}
221			if (! WIFEXITED(status) \|\| WEXITSTATUS(status)) {
222	frodo	314	fprintf(stderr,"Child returned error\n");
223	frodo	295	exit(1);
224			}
225			}
226			}
227
228
229	frodo	290	/* Tiny code to open tap/tun device, and hand the fd to qemu.
230			Run as root, drops to given user. */
231			int main(int argc, char *argv[])
232			{
233			struct ifreq ifr;
234			struct passwd *userdata;
235			char *newargs[argc + 2];
236	frodo	314	int fd,vlan,tapnr;
237			unsigned int i;
238			unsigned new_arg_count = 5;
239			struct gengetopt_args_info args_info;
240	frodo	290	char *display;
241	frodo	314	char *system;
242			char *topleft;
243	frodo	290
244	frodo	314	/* Ugly fix because gengetopt 2.18 does not have the `usage' option */
245			gengetopt_args_info_usage = "qemu-start [OPTIONS] -- [OPTIONS for QEMU]";
246	frodo	290
247	frodo	314	if (cmdline_parser(argc, argv, &args_info))
248	frodo	290	exit(1);
249
250	frodo	314	/* parameter: TAPDEVNR */
251			tapnr = args_info.tapnr_arg;
252
253			/* parameter: VLAN */
254			vlan = args_info.vlan_arg;
255
256			/* parameter: System type */
257			if (args_info.system_given) {
258			if (index(args_info.system_arg,'/')) {
259			fprintf(stderr, "Invalid value `%s' for system (may not contain a slash character)\n", args_info.system_arg);
260			exit(1);
261			}
262			asprintf(&system, "%s", args_info.system_arg);
263	frodo	290	}
264
265	frodo	314	/* parameters: Window location */
266			if (args_info.window_left_given \|\| args_info.window_top_given) {
267			if (!(args_info.window_left_given && args_info.window_top_given)) {
268			fprintf(stderr,("If either window-left (x) or window-top (y) are given, then both must be given\n"));
269			exit(1);
270			}
271			if (asprintf(&topleft, "%d,%d",args_info.window_left_arg,args_info.window_top_arg) < 0) {
272			perror("Preparing top-left environment value string failed");
273			exit(1);
274			}
275	frodo	295	}
276
277			/* Export the xauth data */
278			fix_xauthority();
279
280	frodo	290	/* Open /dev/net/tun */
281			fd = open("/dev/net/tun", O_RDWR);
282			if (fd < 0) {
283			perror("Could not open /dev/net/tun");
284			exit(1);
285			}
286
287			/* Bind to the right tap device */
288			memset(&ifr, 0, sizeof(ifr));
289			ifr.ifr_flags = IFF_TAP \| IFF_NO_PI;
290			snprintf(ifr.ifr_name,IFNAMSIZ,"tap%d",tapnr);
291
292			if (ioctl(fd, TUNSETIFF, (void *) &ifr) != 0) {
293			perror("Could not get tap device");
294			exit(1);
295			}
296
297	frodo	295	/* Get userid data. */
298	frodo	290	userdata = getpwnam(USER);
299			if (!userdata) {
300			fprintf(stderr, "No user '%s'\n", USER);
301			exit(1);
302			}
303	frodo	295
304			/* Change to QEMU user */
305			if (setgroups(0, NULL)) {
306			perror("setgroups failed");
307	frodo	290	exit(1);
308			}
309	frodo	295	if (setgid(userdata->pw_gid)) {
310			perror("setgid failed");
311			exit(1);
312			}
313			if (setuid(userdata->pw_uid)) {
314			perror("setuid failed");
315			exit(1);
316			}
317	frodo	290
318			/* Clean the environment */
319	frodo	295	if(!(display=getenv("DISPLAY"))) {
320			perror("Getting DISPLAY failed");
321			exit(1);
322			}
323			if(clearenv()) {
324			perror("Clearing environment failed");
325			exit(1);
326			}
327			if(setenv("HOME",userdata->pw_dir,1) \|\|
328			setenv("DISPLAY",display,1) \|\|
329			setenv("PATH","/usr/bin:/bin:/usr/local/bin",1) \|\|
330			setenv("LOGNAME",userdata->pw_name,1) \|\|
331			setenv("USER",userdata->pw_name,1)) {
332			perror("Setting environment failed");
333			exit(1);
334			}
335	frodo	314	if (args_info.window_left_given \|\| args_info.window_top_given) {
336			if (setenv("SDL_VIDEO_WINDOW_POS", topleft, 1)) {
337			perror("Setting top-left environment value failed");
338			exit(1);
339			}
340			}
341	frodo	290
342			/* Create the right qemu invocation */
343	frodo	314	if (!args_info.system_given)
344	frodo	290	newargs[0] = QEMU;
345	frodo	314	else if (asprintf(&newargs[0],"%s-system-%s",QEMU,args_info.system_arg) < 0) {
346	frodo	295	perror("Preparing qemu executable filename failed");
347			exit(1);
348			}
349	frodo	290	newargs[1] = "-net";
350	frodo	295	if (asprintf(&newargs[2],"nic,vlan=%d",vlan) < 0) {
351			perror("Preparing nic argument failed");
352			exit(1);
353			}
354	frodo	314	if (args_info.macaddr_given) {
355			if (asprintf(&newargs[2], "%s,mac=%s", newargs[2], args_info.macaddr_arg) < 0) {
356			perror("Adding macaddress to nic argument failed");
357			}
358			}
359			if (args_info.nic_model_given) {
360			if (asprintf(&newargs[2], "%s,model=%s", newargs[2], args_info.nic_model_arg) < 0) {
361			perror("Adding nic model to nic argument failed");
362			}
363			}
364	frodo	290	newargs[3] = "-net";
365	frodo	295	if (asprintf(&newargs[4],"tap,fd=%d,vlan=%d",fd,vlan) < 0) {
366			perror("Preparing tap argument failed");
367			exit(1);
368			}
369	frodo	314	for (i = 0; i < args_info.inputs_num; i++) {
370			newargs[i+5] = args_info.inputs[i];
371			new_arg_count++;
372			}
373			newargs[new_arg_count] = NULL;
374	frodo	290
375			execvp(newargs[0], newargs);
376	frodo	301	perror("Execution of qemu failed");
377	frodo	290	exit(1);
378			}
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