1 /*
2 * Copyright (c) 2016 Cyril Hrubis <chrubis@suse.cz>
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of
7 * the License, or (at your option) any later version.
8 *
9 * This program is distributed in the hope that it would be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18
19 #include <stdio.h>
20 #include <unistd.h>
21 #include <string.h>
22 #include <errno.h>
23 #include <sys/types.h>
24 #include <sys/stat.h>
25 #include <fcntl.h>
26
27 #define WRITE_STRING(fd, string) if (write(fd, string, sizeof(string)-1)) {}
28
main(int argc,char * argv[])29 int main(int argc, char *argv[])
30 {
31 int i, pos = 0;
32 char *args[argc];
33 char *stdin_path = NULL, *stdout_path = NULL, *stderr_path = NULL;
34 int stderr_fd = 0;
35
36 if (argc <= 1) {
37 fprintf(stderr, "%s: Takes at least one agrument!\n", argv[0]);
38 return 1;
39 }
40
41 for (i = 1; i < argc; i++) {
42
43 if (argv[i][0] == '>') {
44 if (argv[i][1]) {
45 stdout_path = argv[i]+1;
46 } else {
47 if (++i >= argc) {
48 fprintf(stderr,
49 "%s: Missing filename after >\n",
50 argv[0]);
51 return 1;
52 }
53 stdout_path = argv[i];
54 }
55 continue;
56 }
57
58 if (argv[i][0] == '<') {
59 if (argv[i][1]) {
60 stdin_path = argv[i]+1;
61 } else {
62 if (++i >= argc) {
63 fprintf(stderr,
64 "%s: Missing filename after <\n",
65 argv[0]);
66 return 1;
67 }
68 stdin_path = argv[i];
69 }
70 continue;
71 }
72
73 if (argv[i][0] == '2' && argv[i][1] == '>') {
74 if (argv[i][2]) {
75 stderr_path = argv[i]+2;
76 } else {
77 if (++i >= argc) {
78 fprintf(stderr,
79 "%s: Missing filename after 2>\n",
80 argv[0]);
81 return 1;
82 }
83 stderr_path = argv[i];
84 }
85 continue;
86 }
87
88 args[pos++] = argv[i];
89 }
90
91 args[pos] = NULL;
92
93 if (stdin_path) {
94 if (close(0)) {
95 fprintf(stderr, "%s: Failed to close stdin: %s\n",
96 argv[0], strerror(errno));
97 return 1;
98 }
99 if (open(stdin_path, O_RDONLY) < 0) {
100 fprintf(stderr,
101 "%s: Failed to open '%s' for reading: %s\n",
102 argv[0], stdin_path, strerror(errno));
103 return 1;
104 }
105 }
106
107 if (stdout_path) {
108 if (close(1)) {
109 fprintf(stderr, "%s: Failed to close stdout: %s\n",
110 argv[0], strerror(errno));
111 return 1;
112 }
113 if (open(stdout_path, O_CREAT|O_WRONLY|O_TRUNC, 0777) < 0) {
114 fprintf(stderr,
115 "%s: Failed to open '%s' for writing: %s\n",
116 argv[0], stdin_path, strerror(errno));
117 return 1;
118 }
119 }
120
121 if (stderr_path) {
122 int fd = open(stderr_path, O_CREAT|O_WRONLY|O_TRUNC, 0777);
123 int stderr_fd = dup(2);
124
125 if (stderr_fd < 0) {
126 fprintf(stderr, "%s: Failed to dup() stderr: %s\n",
127 argv[0], strerror(errno));
128 return 1;
129 }
130
131 if (fd < 0) {
132 fprintf(stderr,
133 "%s: Failed to open '%s' for writing: %s\n",
134 argv[0], stdin_path, strerror(errno));
135 return 1;
136 }
137
138 if (dup2(fd, 2) < 0) {
139 fprintf(stderr, "%s: Failed to dup2 stderr: %s\n",
140 argv[0], strerror(errno));
141 WRITE_STRING(stderr_fd, "Failed to dup2 stderr\n");
142 return 1;
143 }
144 }
145
146 execvp(argv[1], args);
147
148 /* Fall back to shell if command wasn't found */
149 FILE *sin = popen("/bin/sh", "w");
150
151 if (!sin) {
152 if (stderr_fd) {
153 WRITE_STRING(stderr_fd, "Failed to popen /bin/sh\n");
154 } else {
155 fprintf(stderr, "%s: Failed to popen /bin/sh: %s\n",
156 argv[0], strerror(errno));
157 }
158 return 1;
159 }
160
161 //TODO: Should we escape args?
162 for (i = 0; args[i]; i++)
163 fprintf(sin, "%s ", args[i]);
164
165 return !!pclose(sin);
166 }
167