Skip to main content
aboutsummaryrefslogtreecommitdiffstats
blob: d012cfb051c685ffa74bd9f6ece28a8f94a97675 (plain) (blame)
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
#include "exec0.h"
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <libgen.h>
#include <stdlib.h>
#include <termios.h>

/* from pfind.c */
extern char *pfind(const char *name);

pid_t
exec_pty(const char *path, char *const argv[], char *const envp[],
      const char *dirpath, int channels[3], const char *pts_name, int fdm)
{
	int pipe2[2];
	pid_t childpid;
	char *full_path;

	/*
	 * We use pfind() to check that the program exists and is an executable.
	 * If not pass the error up.  Also execve() wants a full path.
	 */ 
	full_path = pfind(path);
	if (full_path == NULL) {
		fprintf(stderr, "Unable to find full path for \"%s\"\n", (path) ? path : "");
		return -1;
	}

	/*
	 *  Make sure we can create our pipes before forking.
	 */ 
	if (channels != NULL) {
		if (pipe(pipe2) < 0) { 
			fprintf(stderr, "%s(%d): returning due to error: %s\n", __FUNCTION__, __LINE__, strerror(errno));
			free(full_path);
			return -1;
		}
	}

	childpid = fork();

	if (childpid < 0) {
		fprintf(stderr, "%s(%d): returning due to error: %s\n", __FUNCTION__, __LINE__, strerror(errno));
		free(full_path);
		return -1;
	} else if (childpid == 0) { /* child */

		chdir(dirpath);

		if (channels != NULL) {
			int fds;

			fds = ptys_open(fdm, pts_name);
			if (fds < 0) {
				fprintf(stderr, "%s(%d): returning due to error: %s\n", __FUNCTION__, __LINE__, strerror(errno));
				return -1;
			}

			/* Close the read end of pipe2 */
			if (close(pipe2[0]) == -1)
				perror("close(pipe2[0]))");

			/* close the master, no need in the child */
			close(fdm);

			set_noecho(fds);
			/* redirections */
			dup2(fds, STDIN_FILENO);   /* dup stdin */
			dup2(fds, STDOUT_FILENO);  /* dup stdout */
			dup2(pipe2[1], STDERR_FILENO);  /* dup stderr */
			close(fds);  /* done with fds. */
		}

		/* Close all the fd's in the child */
		{
			int fdlimit = sysconf(_SC_OPEN_MAX);
			int fd = 3;

			while (fd < fdlimit)
				close(fd++);
		}

		if (envp[0] == NULL) {
			execv(full_path, argv);
		} else {
			execve(full_path, argv, envp);
		}

		_exit(127);

	} else if (childpid != 0) { /* parent */

		set_noecho(fdm);
		if (channels != NULL) {
			/* close the write end of pipe1 */
			if (close(pipe2[1]) == -1)
				perror("close(pipe2[1])");
 
			channels[0] = fdm; /* Input Stream. */
			channels[1] = fdm; /* Output Stream.  */
			channels[2] = pipe2[0]; /* stderr Stream.  */
			//channels[2] = fdm; /* Input Stream.  */
		}

		free(full_path);
		return childpid;
	}

	free(full_path);
	return -1;                  /*NOT REACHED */
}
#ifdef __STAND_ALONE__
int main(int argc, char **argv, char **envp) {
	const char *path = "./bufferring_test";
	int channels[3] = { -1, -1, -1};
	int status;	
	FILE *app_stdin;
	FILE *app_stdout;
	FILE *app_stderr;
	char pts_name[32];
	int fdm;	
	char buffer[32];

	fdm = ptym_open(pts_name);
	status =  exec_pty(path, argv, envp, ".", channels, pts_name, fdm);
	if (status >= 0) {
		app_stdin = fdopen(channels[0], "w");	
		app_stdout = fdopen(channels[1], "r");	
		app_stderr = fdopen(channels[2], "r");	
		if (app_stdout == NULL || app_stderr == NULL || app_stdin == NULL) {
			fprintf(stderr, "PROBLEMS\n");
		} else {
			fputs("foo\n", app_stdin);
			fputs("bar\n", app_stdin);
			while(fgets(buffer, sizeof buffer, app_stdout) != NULL) {
				fprintf(stdout, "STDOUT: %s\n", buffer);
			}
			while(fgets(buffer, sizeof buffer, app_stderr) != NULL) {
				fprintf(stdout, "STDERR: %s\n", buffer);
			}
		}
	}
	fputs("bye\n", stdout);
	close(channels[0]);
	close(channels[1]);
	close(channels[2]);
	return 0;	
}
#endif

Back to the top