summaryrefslogtreecommitdiffstats
path: root/tdesu/tdesu_stub.c
blob: f8054a3136526b7a7aee49206018b7bd09b84e16 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
/* vi: ts=8 sts=4 sw=4
 *
 * $Id$
 *
 * This file is part of the KDE project, module tdesu.
 * Copyright (C) 1999,2000 Geert Jansen <jansen@kde.org>
 *
 * tdesu_stub.c: KDE su executes this stub through su or ssh. This stub in turn
 *               executes the target program. Before that, startup parameters
 *               are sent through stdin.
 *
 *
 * Available parameters:
 *
 *   Parameter       Description         Format (csl = comma separated list)
 *
 * - tdesu_stub      Header              "ok" | "stop"
 * - display         X11 display         string
 * - display_auth    X11 authentication  "type cookie" pair
 * - dcopserver      KDE dcopserver      csl of netids
 * - dcop_auth       DCOP authentication csl of "type cookie" pairs for DCOP
 * - ice_auth        ICE authentication  csl of "type cookie" pairs for ICE
 * - command         Command to run      string
 * - path            PATH env. var       string
 * - build_sycoca    Rebuild sycoca?     "yes" | "no"
 * - user            Target user         string
 * - priority        Process priority    0 <= int <= 100
 * - scheduler       Process scheduler   "fifo" | "normal"
 * - app_startup_id  DESKTOP_STARTUP_ID  string
 * - environment     Additional envvars  strings, last one is empty
 */

#include <config.h>

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <pwd.h>
#include <termios.h>
#include <signal.h>

#ifdef HAVE_INITGROUPS
#include <grp.h>
#endif

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/time.h>
#include <sys/resource.h>

#ifdef POSIX1B_SCHEDULING
#include <sched.h>
#endif

/**
 * Params sent by the peer.
 */

struct param_struct 
{
    const char *name;
    char *value;
};

struct param_struct params[] = 
{
    { "tdesu_stub", 0L },
    { "display", 0L },
    { "display_auth", 0L },
    { "dcopserver", 0L },
    { "dcop_auth", 0L },
    { "ice_auth", 0L },
    { "command", 0L },
    { "path", 0L },
    { "xwindows_only", 0L },
    { "user", 0L },
    { "priority", 0L },
    { "scheduler", 0L },
/* obsoleted by app_startup_id    { "app_start_pid", 0L } */
    { "app_startup_id", 0L }
};

#define P_HEADER 0
#define P_DISPLAY 1
#define P_DISPLAY_AUTH 2
#define P_DCOPSERVER 3
#define P_DCOP_AUTH 4
#define P_ICE_AUTH 5
#define P_COMMAND 6
#define P_PATH 7
#define P_XWIN_ONLY 8
#define P_USER 9
#define P_PRIORITY 10
#define P_SCHEDULER 11
#define P_APP_STARTUP_ID 12
#define P_LAST 13

/* Prototypes */
char *xmalloc(size_t);
char *xrealloc(char *ptr, int size);
int xsetenv(const char *name, const char *value);
char *xstrdup(char *src);
char **xstrsep(char *str);

/**
 * Safe malloc functions.
 */
char *xmalloc(size_t size)
{
    char *ptr = malloc(size);
    if (ptr) return ptr;
    perror("malloc()");
    exit(1);
}


char *xrealloc(char *ptr, int size)
{
    ptr = realloc(ptr, size);
    if (ptr) return ptr;
    perror("realloc()");
    exit(1);
}


/**
 * Solaris does not have a setenv()...
 */
int xsetenv(const char *name, const char *value)
{
    char *s = malloc(strlen(name)+strlen(value)+2);
    if (!s) return -1;
    strcpy(s, name);
    strcat(s, "=");
    strcat(s, value);
    return putenv(s); /* yes: no free()! */
}

/**
 * Safe strdup and strip newline
 */
char *xstrdup(char *src)
{
    int len = strlen(src);
    char *dst = xmalloc(len+1);
    strcpy(dst, src);
    if (dst[len-1] == '\n')
	dst[len-1] = '\000';
    return dst;
}

/**
 * Split comma separated list.
 */
char **xstrsep(char *str)
{
    int i = 0, size = 10;
    char **list = (char **) xmalloc(size * sizeof(char *));
    char *ptr = str, *nptr;
    while ((nptr = strchr(ptr, ',')) != 0L) 
    {
	if (i > size-2)
	    list = realloc(list, (size *= 2) * sizeof(char *));
	*nptr = '\000';
	list[i++] = ptr;
	ptr = nptr+1;
    }
    if (*ptr != '\000')
	list[i++] = ptr;
    list[i] = 0L;
    return list;
}

#define BUFSIZE	8192

/**
 * The main program
 */

int main()
{
    char buf[BUFSIZE+1];
#ifndef QWS
    char xauthority[200];
#endif
    char iceauthority[200];
    char **host, **auth;
    int i/*, res, sycoca*/, prio;
    pid_t pid;
    FILE *fout;
    struct passwd *pw;
    const char* tdesu_lc_all;

    /* Get startup parameters. */

    for (i=0; i<P_LAST; i++) 
    {
	printf("%s\n", params[i].name);
	fflush(stdout);
	if (fgets(buf, BUFSIZE, stdin) == 0L) 
	{
	    printf("end\n"); fflush(stdout);
	    perror("tdesu_stub: fgets()");
	    exit(1);
	}
	params[i].value = xstrdup(buf);
	/* Installation check? */
	if ((i == 0) && !strcmp(params[i].value, "stop")) 
	{
	    printf("end\n");
	    exit(0);
	}
    }
    printf("environment\n");
    fflush(stdout);
    for(;;)
    {
	char* tmp;
	if (fgets(buf, BUFSIZE, stdin) == 0L) 
	{
	    printf("end\n"); fflush(stdout);
	    perror("tdesu_stub: fgets()");
	    exit(1);
	}
	tmp = xstrdup( buf );
	if( tmp[ 0 ] == '\0' ) /* terminator */
	    break;
	putenv( xstrdup( buf ));
    }

    printf("end\n");
    fflush(stdout);

    xsetenv("PATH", params[P_PATH].value);
    xsetenv("DESKTOP_STARTUP_ID", params[P_APP_STARTUP_ID].value);

    tdesu_lc_all = getenv( "TDESU_LC_ALL" );
    if( tdesu_lc_all != NULL )
        xsetenv("LC_ALL",tdesu_lc_all);
    else
        unsetenv("LC_ALL");

    /* Do we need to change uid? */

    pw = getpwnam(params[P_USER].value);
    if (pw == 0L) 
    {
	printf("tdesu_stub: user %s does not exist!\n", params[P_USER].value);
	exit(1);
    }
    xsetenv("HOME", pw->pw_dir);

    /* Set scheduling/priority */

    prio = atoi(params[P_PRIORITY].value);
    if (!strcmp(params[P_SCHEDULER].value, "realtime")) 
    {
#ifdef POSIX1B_SCHEDULING
	struct sched_param sched;
	int min = sched_get_priority_min(SCHED_FIFO);
	int max = sched_get_priority_max(SCHED_FIFO);
	sched.sched_priority = min + (int) (((double) prio) * (max - min) / 100 + 0.5);
	sched_setscheduler(0, SCHED_FIFO, &sched);
#else
	printf("tdesu_stub: realtime scheduling not supported\n");
#endif
    } else 
    {
#ifdef HAVE_SETPRIORITY
	int val = 20 - (int) (((double) prio) * 40 / 100 + 0.5);
	setpriority(PRIO_PROCESS, getpid(), val);
#endif 
    }

    /* Drop privileges (this is permanent) */

    if (getuid() != pw->pw_uid) 
    {
	if (setgid(pw->pw_gid) == -1) 
	{
	    perror("tdesu_stub: setgid()");
	    exit(1);
	}
#ifdef HAVE_INITGROUPS
	if (initgroups(pw->pw_name, pw->pw_gid) == -1) 
	{
	    perror("tdesu_stub: initgroups()");
	    exit(1);
	}
#endif
	if (setuid(pw->pw_uid) == -1) 
	{
	    perror("tdesu_stub: setuid()");
	    exit(1);
	}
	xsetenv("HOME", pw->pw_dir);
    }

    /* Handle display */

    if (strcmp(params[P_DISPLAY].value, "no")) 
    {
#ifndef QWS
	xsetenv("DISPLAY", params[P_DISPLAY].value);
	if (params[P_DISPLAY_AUTH].value[0]) 
	{
           int	fd2;
           /*
           ** save umask and set to 077, so we create those files only
	   ** readable for root. (if someone else could read them, we
	   ** are in deep shit).
           */
	   int oldumask = umask(077);
	   const char *disp = params[P_DISPLAY].value;
	   if (strncmp(disp, "localhost:", 10) == 0)
	      disp += 9;

           strcpy(xauthority, "/tmp/xauth.XXXXXXXXXX");
	   fd2 = mkstemp(xauthority);
	   umask(oldumask);

           if (fd2 == -1) {
                perror("tdesu_stub: mkstemp()");
                exit(1);
           } else
                close(fd2);
           xsetenv("XAUTHORITY", xauthority);

	   fout = popen("xauth >/dev/null 2>&1","w");
           if (fout == NULL)
	   {
		perror("tdesu_stub: popen(xauth)");
		exit(1);
	   }
	   fprintf(fout, "add %s %s\n", disp,
		    params[P_DISPLAY_AUTH].value);
	   pclose(fout);
	}
#else
	xsetenv("DISPLAY", params[P_DISPLAY].value);
#endif
    }


    /* Handle DCOP */

    if (strcmp(params[P_DCOPSERVER].value, "no")) 
    {
	xsetenv("DCOPSERVER", params[P_DCOPSERVER].value);
	host = xstrsep(params[P_DCOPSERVER].value);
	auth = xstrsep(params[P_ICE_AUTH].value);
	if (host[0]) 
	{
            int fd;
	    int	oldumask = umask(077);

            strcpy(iceauthority, "/tmp/iceauth.XXXXXXXXXX");
            fd = mkstemp(iceauthority);
	    umask(oldumask);
            if (fd == -1) {
                perror("tdesu_stub: mkstemp()");
                exit(1);
            } else
                close(fd);
	    xsetenv("ICEAUTHORITY", iceauthority);

	    fout = popen("iceauth >/dev/null 2>&1", "w");
	    if (!fout) {
		perror("tdesu_stub: popen iceauth");
		exit(1);
	    }
	    for (i=0; host[i]; i++)
		fprintf(fout, "add ICE \"\" %s %s\n", host[i], auth[i]);
	    auth = xstrsep(params[P_DCOP_AUTH].value);
	    for (i=0; host[i]; i++)
		fprintf(fout, "add DCOP \"\" %s %s\n", host[i], auth[i]);
	    pclose(fout);
	}
    }

    /* Rebuild the sycoca and start tdeinit? */

    if (strcmp(params[P_XWIN_ONLY].value, "no"))
    {
	system("tdeinit --suicide");
    }

    /* Execute the command */

    pid = fork();
    if (pid == -1) 
    {
	perror("tdesu_stub: fork()");
	exit(1);
    }
    if (pid) 
    {
	/* Parent: wait for child, delete tempfiles and return. */
	int ret, state, xit = 1;
	while (1) 
	{
	    ret = waitpid(pid, &state, 0);
	    if (ret == -1) 
	    {
		if (errno == EINTR)
		    continue;
		if (errno != ECHILD)
		    perror("tdesu_stub: waitpid()");
		break;
	    }
	    if (WIFEXITED(state))
		xit = WEXITSTATUS(state);
	}

#ifndef QWS
	unlink(xauthority);
#endif
	unlink(iceauthority);
	exit(xit);
    } else 
    {
        setsid();
	/* Child: exec command. */
	sprintf(buf, "%s", params[P_COMMAND].value);
	execl("/bin/sh", "sh", "-c", buf, (void *)0);
	perror("tdesu_stub: exec()");
	_exit(1);
    }
}