trunk/rdesktop/readpass.c

/*
   rdesktop: A Remote Desktop Protocol client.
   User interface services - X keyboard mapping
   Copyright (C) Matthew Chapman 1999-2001
   
   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.
*/

#include <sys/types.h>
#include <signal.h>
#include <stdio.h>
#include <errno.h>
#include "rdesktop.h"
#include <assert.h>
#include <unistd.h>
#include <sys/wait.h>

/* Execute specified askpass program and fetch password from standard
   output. Return NULL on failure, otherwise a pointer to the data
   read (which must be freed by caller) */

char *
askpass(char *askpass, const char *msg)
{
        pid_t pid;
        size_t len;
        char *pass;
        int p[2], status, ret;
        char buf[1024];

        if (fflush(stdout) != 0)
                error("askpass: fflush: %s", strerror(errno));
        assert(askpass != NULL);
        if (pipe(p) < 0)
        {
                error("askpass: pipe: %s", strerror(errno));
                return NULL;
        }

        pid = fork();
        switch (pid)
        {
                case -1:
                        error("askpass: fork: %s", strerror(errno));
                        return NULL;
                        break;
                case 0:
                        /* Child */
                        seteuid(getuid());
                        setuid(getuid());
                        /* Close read end */
                        close(p[0]);
                        if (dup2(p[1], STDOUT_FILENO) < 0)
                        {
                                error("askpass: dup2: %s", strerror(errno));
                                exit(1);
                        }
                        execlp(askpass, askpass, msg, (char *) 0);
                        error("askpass: exec(%s): %s", askpass, strerror(errno));
                        exit(1);
                        break;
                default:
                        /* Parent */
                        break;
        }
        /* Close write end */
        close(p[1]);

        len = ret = 0;
        do
        {
                ret = read(p[0], buf + len, sizeof(buf) - 1 - len);

                if (ret == -1 && errno == EINTR)
                        continue;
                if (ret <= 0)
                        break;

                len += ret;
        }
        while (sizeof(buf) - 1 - len > 0);


        buf[len] = '\0';

        close(p[0]);
        while (waitpid(pid, &status, 0) < 0)
                if (errno != EINTR)
                        break;

        if (WIFEXITED(status))
        {
                if (WEXITSTATUS(status))
                {
                        error("askpass program returned %d\n", WEXITSTATUS(status));
                        return NULL;
                }
        }
        else
        {
                error("abnormal exit from askpass program");
                return NULL;
        }

        buf[strcspn(buf, "\r\n")] = '\0';
        pass = strdup(buf);
        memset(buf, 0, sizeof(buf));
        return pass;
}
1	astrand	96	/*
2			rdesktop: A Remote Desktop Protocol client.
3			User interface services - X keyboard mapping
4			Copyright (C) Matthew Chapman 1999-2001
5
6			This program is free software; you can redistribute it and/or modify
7			it under the terms of the GNU General Public License as published by
8			the Free Software Foundation; either version 2 of the License, or
9			(at your option) any later version.
10
11			This program is distributed in the hope that it will be useful,
12			but WITHOUT ANY WARRANTY; without even the implied warranty of
13			MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14			GNU General Public License for more details.
15
16			You should have received a copy of the GNU General Public License
17			along with this program; if not, write to the Free Software
18			Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19			*/
20
21			#include <sys/types.h>
22			#include <signal.h>
23			#include <stdio.h>
24			#include <errno.h>
25			#include "rdesktop.h"
26			#include <assert.h>
27			#include <unistd.h>
28			#include <sys/wait.h>
29
30			/* Execute specified askpass program and fetch password from standard
31			output. Return NULL on failure, otherwise a pointer to the data
32			read (which must be freed by caller) */
33
34			char *
35			askpass(char askpass, const char msg)
36			{
37			pid_t pid;
38			size_t len;
39			char *pass;
40			int p[2], status, ret;
41			char buf[1024];
42
43			if (fflush(stdout) != 0)
44			error("askpass: fflush: %s", strerror(errno));
45			assert(askpass != NULL);
46			if (pipe(p) < 0)
47			{
48			error("askpass: pipe: %s", strerror(errno));
49			return NULL;
50			}
51
52			pid = fork();
53			switch (pid)
54			{
55			case -1:
56			error("askpass: fork: %s", strerror(errno));
57			return NULL;
58			break;
59			case 0:
60			/* Child */
61			seteuid(getuid());
62			setuid(getuid());
63			/* Close read end */
64			close(p[0]);
65			if (dup2(p[1], STDOUT_FILENO) < 0)
66			{
67			error("askpass: dup2: %s", strerror(errno));
68			exit(1);
69			}
70			execlp(askpass, askpass, msg, (char *) 0);
71			error("askpass: exec(%s): %s", askpass, strerror(errno));
72			exit(1);
73			break;
74			default:
75			/* Parent */
76			break;
77			}
78			/* Close write end */
79			close(p[1]);
80
81			len = ret = 0;
82			do
83			{
84			ret = read(p[0], buf + len, sizeof(buf) - 1 - len);
85
86			if (ret == -1 && errno == EINTR)
87			continue;
88			if (ret <= 0)
89			break;
90
91			len += ret;
92			}
93			while (sizeof(buf) - 1 - len > 0);
94
95
96			buf[len] = '\0';
97
98			close(p[0]);
99			while (waitpid(pid, &status, 0) < 0)
100			if (errno != EINTR)
101			break;
102
103			if (WIFEXITED(status))
104			{
105			if (WEXITSTATUS(status))
106			{
107			error("askpass program returned %d\n", WEXITSTATUS(status));
108			return NULL;
109			}
110			}
111			else
112			{
113			error("abnormal exit from askpass program");
114			return NULL;
115			}
116
117			buf[strcspn(buf, "\r\n")] = '\0';
118			pass = strdup(buf);
119			memset(buf, 0, sizeof(buf));
120			return pass;
121			}