1 | /* Copyright 2000 by the Massachusetts Institute of Technology. |
---|
2 | * |
---|
3 | * Permission to use, copy, modify, and distribute this |
---|
4 | * software and its documentation for any purpose and without |
---|
5 | * fee is hereby granted, provided that the above copyright |
---|
6 | * notice appear in all copies and that both that copyright |
---|
7 | * notice and this permission notice appear in supporting |
---|
8 | * documentation, and that the name of M.I.T. not be used in |
---|
9 | * advertising or publicity pertaining to distribution of the |
---|
10 | * software without specific, written prior permission. |
---|
11 | * M.I.T. makes no representations about the suitability of |
---|
12 | * this software for any purpose. It is provided "as is" |
---|
13 | * without express or implied warranty. |
---|
14 | */ |
---|
15 | |
---|
16 | /* attachandrun - attach a locker and run a program out of it. |
---|
17 | * Intended mainly for use by scripts. |
---|
18 | */ |
---|
19 | |
---|
20 | static const char rcsid[] = "$Id: attachandrun.c,v 1.3 2002-05-06 14:51:20 ghudson Exp $"; |
---|
21 | |
---|
22 | #include <sys/types.h> |
---|
23 | #include <sys/stat.h> |
---|
24 | #include <sys/wait.h> |
---|
25 | #include <stdio.h> |
---|
26 | #include <stdlib.h> |
---|
27 | #include <string.h> |
---|
28 | #include <ctype.h> |
---|
29 | #include <unistd.h> |
---|
30 | #include <fcntl.h> |
---|
31 | #include <errno.h> |
---|
32 | #include <athdir.h> |
---|
33 | |
---|
34 | static char *run_attach(const char *locker); |
---|
35 | static char *read_from_pipe(int fd); |
---|
36 | static void try_shell_exec(char *path, int argc, char **argv); |
---|
37 | static void *emalloc(size_t size); |
---|
38 | static void *erealloc(void *ptr, size_t size); |
---|
39 | static void usage(void); |
---|
40 | |
---|
41 | static const char *progname; |
---|
42 | |
---|
43 | int main(int argc, char **argv) |
---|
44 | { |
---|
45 | const char *locker, *program; |
---|
46 | char *locker_path, **paths, *prog_path; |
---|
47 | int check = 0; |
---|
48 | |
---|
49 | progname = strrchr(argv[0], '/'); |
---|
50 | progname = (progname == NULL) ? argv[0] : progname + 1; |
---|
51 | |
---|
52 | /* Process arguments. Leave argc/argv specifying the arguments for |
---|
53 | * the command to run. |
---|
54 | */ |
---|
55 | if (argc >= 2 && |
---|
56 | (strcmp(argv[1], "--check") == 0 || strcmp(argv[1], "-c") == 0)) |
---|
57 | { |
---|
58 | if (argc < 3) |
---|
59 | usage(); |
---|
60 | |
---|
61 | check = 1; |
---|
62 | argc--; |
---|
63 | argv++; |
---|
64 | } |
---|
65 | else if (argc < 4) |
---|
66 | usage(); |
---|
67 | locker = argv[1]; |
---|
68 | program = argv[2]; |
---|
69 | argc -= 3; |
---|
70 | argv += 3; |
---|
71 | |
---|
72 | /* Run attach and get the path to run. */ |
---|
73 | locker_path = run_attach(locker); |
---|
74 | paths = athdir_get_paths(locker_path, "bin", NULL, NULL, NULL, NULL, 0); |
---|
75 | if (paths == NULL) |
---|
76 | { |
---|
77 | fprintf(stderr, "%s: can't find a binary directory in %s\n", |
---|
78 | progname, locker_path); |
---|
79 | exit(1); |
---|
80 | } |
---|
81 | prog_path = emalloc(strlen(paths[0]) + 1 + strlen(program) + 1); |
---|
82 | sprintf(prog_path, "%s/%s", paths[0], program); |
---|
83 | athdir_free_paths(paths); |
---|
84 | |
---|
85 | /* If we're just doing a check, do that now and exit. */ |
---|
86 | if (check) |
---|
87 | exit((access(prog_path, X_OK) == 0) ? 0 : 1); |
---|
88 | |
---|
89 | /* Run the command. */ |
---|
90 | execv(prog_path, argv); |
---|
91 | if (errno == ENOEXEC) |
---|
92 | try_shell_exec(prog_path, argc, argv); |
---|
93 | fprintf(stderr, "%s: failure to exec %s: %s\n", progname, program, |
---|
94 | strerror(errno)); |
---|
95 | exit(1); |
---|
96 | } |
---|
97 | |
---|
98 | /* Run attach -p <lockername> and return the locker path attach prints. */ |
---|
99 | static char *run_attach(const char *locker) |
---|
100 | { |
---|
101 | pid_t pid; |
---|
102 | int fds[2], status; |
---|
103 | char *locker_path; |
---|
104 | |
---|
105 | if (pipe(fds) == -1) |
---|
106 | { |
---|
107 | fprintf(stderr, "%s: pipe failed: %s\n", progname, strerror(errno)); |
---|
108 | exit(1); |
---|
109 | } |
---|
110 | |
---|
111 | pid = fork(); |
---|
112 | if (pid == -1) |
---|
113 | { |
---|
114 | fprintf(stderr, "%s: fork failed: %s\n", progname, strerror(errno)); |
---|
115 | exit(1); |
---|
116 | } |
---|
117 | else if (pid == 0) |
---|
118 | { |
---|
119 | /* In the child, run attach with stdout directed at the write |
---|
120 | * side of the pipe. |
---|
121 | */ |
---|
122 | close(fds[0]); |
---|
123 | dup2(fds[1], STDOUT_FILENO); |
---|
124 | if (fds[1] != STDOUT_FILENO) |
---|
125 | close(fds[1]); |
---|
126 | execl("/bin/athena/attach", "attach", "-p", locker, (char *) NULL); |
---|
127 | fprintf(stderr, "%s: execl failed: %s\n", progname, strerror(errno)); |
---|
128 | _exit(1); |
---|
129 | } |
---|
130 | |
---|
131 | /* In the parent, read the locker path from the pipe. */ |
---|
132 | close(fds[1]); |
---|
133 | locker_path = read_from_pipe(fds[0]); |
---|
134 | close(fds[0]); |
---|
135 | waitpid(pid, &status, 0); |
---|
136 | if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) |
---|
137 | exit(1); |
---|
138 | if (!*locker_path) |
---|
139 | { |
---|
140 | fprintf(stderr, "%s: attach failed to output locker path\n", progname); |
---|
141 | exit(1); |
---|
142 | } |
---|
143 | return locker_path; |
---|
144 | } |
---|
145 | |
---|
146 | static char *read_from_pipe(int fd) |
---|
147 | { |
---|
148 | char *buf; |
---|
149 | int count, pos, sz; |
---|
150 | |
---|
151 | sz = BUFSIZ; |
---|
152 | buf = emalloc(sz + 1); |
---|
153 | pos = 0; |
---|
154 | while (1) |
---|
155 | { |
---|
156 | count = read(fd, buf + pos, sz - pos); |
---|
157 | if (count == -1) |
---|
158 | { |
---|
159 | fprintf(stderr, "%s: read from pipe failed: %s\n", progname, |
---|
160 | strerror(errno)); |
---|
161 | exit(1); |
---|
162 | } |
---|
163 | else if (count == 0) |
---|
164 | { |
---|
165 | buf[pos] = 0; |
---|
166 | if (pos > 0 && buf[pos - 1] == '\n') |
---|
167 | buf[pos - 1] = 0; |
---|
168 | return buf; |
---|
169 | } |
---|
170 | pos += count; |
---|
171 | if (pos == sz) |
---|
172 | { |
---|
173 | sz += BUFSIZ; |
---|
174 | buf = erealloc(buf, sz + 1); |
---|
175 | } |
---|
176 | } |
---|
177 | } |
---|
178 | |
---|
179 | /* Try to feed a text file to the shell by hand. On error, errno will |
---|
180 | * be the error value from open() or read() or execv(), or ENOEXEC if |
---|
181 | * the file looks binary, or ENOMEM if we couldn't allocate memory for |
---|
182 | * an argument list. |
---|
183 | */ |
---|
184 | static void try_shell_exec(char *path, int argc, char **argv) |
---|
185 | { |
---|
186 | int i, count, fd, err; |
---|
187 | unsigned char sample[128]; |
---|
188 | char **arg; |
---|
189 | |
---|
190 | /* First we should check if the file looks binary. Open the file. */ |
---|
191 | fd = open(path, O_RDONLY, 0); |
---|
192 | if (fd == -1) |
---|
193 | return; |
---|
194 | |
---|
195 | /* Read in a bit of data from the file. */ |
---|
196 | count = read(fd, sample, sizeof(sample)); |
---|
197 | err = errno; |
---|
198 | close(fd); |
---|
199 | if (count < 0) |
---|
200 | { |
---|
201 | errno = err; |
---|
202 | return; |
---|
203 | } |
---|
204 | |
---|
205 | /* Look for binary characters in the first line. */ |
---|
206 | for (i = 0; i < count; i++) |
---|
207 | { |
---|
208 | if (sample[i] == '\n') |
---|
209 | break; |
---|
210 | if (!isspace(sample[i]) && !isprint(sample[i])) |
---|
211 | { |
---|
212 | errno = ENOEXEC; |
---|
213 | return; |
---|
214 | } |
---|
215 | } |
---|
216 | |
---|
217 | /* Allocate space for a longer argument list. */ |
---|
218 | arg = malloc((argc + 2) * sizeof(char *)); |
---|
219 | if (!arg) |
---|
220 | { |
---|
221 | errno = ENOMEM; |
---|
222 | return; |
---|
223 | } |
---|
224 | |
---|
225 | /* Set up the argument list. Copy in the argument part of argv |
---|
226 | * including the terminating NULL. argv[0] is lost, unfortunately. |
---|
227 | */ |
---|
228 | arg[0] = "/bin/sh"; |
---|
229 | arg[1] = path; |
---|
230 | memcpy(arg + 2, argv + 1, argc * sizeof(char *)); |
---|
231 | |
---|
232 | execv(arg[0], arg); |
---|
233 | free(arg); |
---|
234 | return; |
---|
235 | } |
---|
236 | |
---|
237 | static void *emalloc(size_t size) |
---|
238 | { |
---|
239 | void *ptr; |
---|
240 | |
---|
241 | ptr = malloc(size); |
---|
242 | if (!ptr) |
---|
243 | { |
---|
244 | fprintf(stderr, "%s: malloc size %lu failed", progname, |
---|
245 | (unsigned long) size); |
---|
246 | exit(1); |
---|
247 | } |
---|
248 | return ptr; |
---|
249 | } |
---|
250 | |
---|
251 | static void *erealloc(void *ptr, size_t size) |
---|
252 | { |
---|
253 | ptr = realloc(ptr, size); |
---|
254 | if (!ptr) |
---|
255 | { |
---|
256 | fprintf(stderr, "%s: realloc size %lu failed", progname, |
---|
257 | (unsigned long) size); |
---|
258 | exit(1); |
---|
259 | } |
---|
260 | return ptr; |
---|
261 | } |
---|
262 | |
---|
263 | static void usage(void) |
---|
264 | { |
---|
265 | fprintf(stderr, "Usage: %s [--check] locker program argv0 [argv1...]\n", |
---|
266 | progname); |
---|
267 | exit(1); |
---|
268 | } |
---|