1 /*
2 * This wrapper program executes a python executable hidden inside an
3 * application bundle inside the Python framework. This is needed to run
4 * GUI code: some GUI API's don't work unless the program is inside an
5 * application bundle.
6 *
7 * This program uses posix_spawn rather than plain execv because we need
8 * slightly more control over how the "real" interpreter is executed.
9 *
10 * On OSX 10.4 (and earlier) this falls back to using exec because the
11 * posix_spawnv functions aren't available there.
12 */
13
14 #pragma weak_import posix_spawnattr_init
15 #pragma weak_import posix_spawnattr_setbinpref_np
16 #pragma weak_import posix_spawnattr_setflags
17 #pragma weak_import posix_spawn
18
19 #include <Python.h>
20 #include <unistd.h>
21 #ifdef HAVE_SPAWN_H
22 #include <spawn.h>
23 #endif
24 #include <stdio.h>
25 #include <string.h>
26 #include <errno.h>
27 #include <err.h>
28 #include <dlfcn.h>
29 #include <stdlib.h>
30 #include <mach-o/dyld.h>
31
32
33 extern char** environ;
34
35 /*
36 * Locate the python framework by looking for the
37 * library that contains Py_Initialize.
38 *
39 * In a regular framework the structure is:
40 *
41 * Python.framework/Versions/2.7
42 * /Python
43 * /Resources/Python.app/Contents/MacOS/Python
44 *
45 * In a virtualenv style structure the expected
46 * structure is:
47 *
48 * ROOT
49 * /bin/pythonw
50 * /.Python <- the dylib
51 * /.Resources/Python.app/Contents/MacOS/Python
52 *
53 * NOTE: virtualenv's are not an officially supported
54 * feature, support for that structure is provided as
55 * a convenience.
56 */
57 static char* get_python_path(void)
58 {
59 size_t len;
60 Dl_info info;
61 char* end;
62 char* g_path;
63
64 if (dladdr(Py_Initialize, &info) == 0) {
65 return NULL;
66 }
67
68 len = strlen(info.dli_fname);
69
70 g_path = malloc(len+60);
71 if (g_path == NULL) {
72 return NULL;
73 }
74
75 strcpy(g_path, info.dli_fname);
76 end = g_path + len - 1;
77 while (end != g_path && *end != '/') {
78 end --;
79 }
80 end++;
81 if (*end == '.') {
82 end++;
83 }
84 strcpy(end, "Resources/Python.app/Contents/MacOS/" PYTHONFRAMEWORK);
85
86 return g_path;
87 }
88
89 #ifdef HAVE_SPAWN_H
90 static void
91 setup_spawnattr(posix_spawnattr_t* spawnattr)
92 {
93 size_t ocount;
94 size_t count;
95 cpu_type_t cpu_types[1];
96 short flags = 0;
97
98 if ((errno = posix_spawnattr_init(spawnattr)) != 0) {
99 err(2, "posix_spawnattr_int");
100 /* NOTREACHTED */
101 }
102
103 count = 1;
104
105 /* Run the real python executable using the same architecture as this
106 * executable, this allows users to control the architecture using
107 * "arch -ppc python"
108 */
109
110 #if defined(__ppc64__)
111 cpu_types[0] = CPU_TYPE_POWERPC64;
112
113 #elif defined(__x86_64__)
114 cpu_types[0] = CPU_TYPE_X86_64;
115
116 #elif defined(__ppc__)
117 cpu_types[0] = CPU_TYPE_POWERPC;
118
119 #elif defined(__i386__)
120 cpu_types[0] = CPU_TYPE_X86;
121
122 #elif defined(__arm64__)
123 cpu_types[0] = CPU_TYPE_ARM64;
124
125 #else
126 # error "Unknown CPU"
127
128 #endif
129
130 if (posix_spawnattr_setbinpref_np(spawnattr, count,
131 cpu_types, &ocount) == -1) {
132 err(1, "posix_spawnattr_setbinpref");
133 /* NOTREACHTED */
134 }
135 if (count != ocount) {
136 fprintf(stderr, "posix_spawnattr_setbinpref failed to copy\n");
137 exit(1);
138 /* NOTREACHTED */
139 }
140
141
142 /*
143 * Set flag that causes posix_spawn to behave like execv
144 */
145 flags |= POSIX_SPAWN_SETEXEC;
146 if ((errno = posix_spawnattr_setflags(spawnattr, flags)) != 0) {
147 err(1, "posix_spawnattr_setflags");
148 /* NOTREACHTED */
149 }
150 }
151 #endif
152
153 int
154 main(int argc, char **argv) {
155 char* exec_path = get_python_path();
156 static char path[PATH_MAX * 2];
157 static char real_path[PATH_MAX * 2];
158 int status;
159 uint32_t size = PATH_MAX * 2;
160
161 /* Set the original executable path in the environment. */
162 status = _NSGetExecutablePath(path, &size);
163 if (status == 0) {
164 /*
165 * Note: don't call 'realpath', that will
166 * erase symlink information, and that
167 * breaks "pyvenv --symlink"
168 *
169 * It is nice to have the directory name
170 * as a cleaned up absolute path though,
171 * therefore call realpath on dirname(path)
172 */
173 char* slash = strrchr(path, '/');
174 if (slash) {
175 char replaced;
176 replaced = slash[1];
177 slash[1] = 0;
178 if (realpath(path, real_path) == NULL) {
179 err(1, "realpath: %s", path);
180 }
181 slash[1] = replaced;
182 if (strlcat(real_path, slash, sizeof(real_path)) > sizeof(real_path)) {
183 errno = EINVAL;
184 err(1, "realpath: %s", path);
185 }
186
187 } else {
188 if (realpath(".", real_path) == NULL) {
189 err(1, "realpath: %s", path);
190 }
191 if (strlcat(real_path, "/", sizeof(real_path)) > sizeof(real_path)) {
192 errno = EINVAL;
193 err(1, "realpath: %s", path);
194 }
195 if (strlcat(real_path, path, sizeof(real_path)) > sizeof(real_path)) {
196 errno = EINVAL;
197 err(1, "realpath: %s", path);
198 }
199 }
200
201 /*
202 * The environment variable is used to pass the value of real_path
203 * to the actual python interpreter, and is read by code in
204 * Python/coreconfig.c.
205 *
206 * This way the real interpreter knows how the user invoked the
207 * interpreter and can behave as if this launcher is the real
208 * interpreter (looking for pyvenv configuration, ...)
209 */
210 setenv("__PYVENV_LAUNCHER__", real_path, 1);
211 }
212
213 /*
214 * Let argv[0] refer to the new interpreter. This is needed to
215 * get the effect we want on OSX 10.5 or earlier. That is, without
216 * changing argv[0] the real interpreter won't have access to
217 * the Window Server.
218 */
219 argv[0] = exec_path;
220
221 #ifdef HAVE_SPAWN_H
222 /* We're weak-linking to posix-spawnv to ensure that
223 * an executable build on 10.5 can work on 10.4.
224 */
225
226 if (&posix_spawn != NULL) {
227 posix_spawnattr_t spawnattr = NULL;
228
229 setup_spawnattr(&spawnattr);
230 posix_spawn(NULL, exec_path, NULL,
231 &spawnattr, argv, environ);
232 err(1, "posix_spawn: %s", exec_path);
233 }
234 #endif
235 execve(exec_path, argv, environ);
236 err(1, "execve: %s", argv[0]);
237 /* NOTREACHED */
238 }