1 #include "cache.h"
2 #include "exec-cmd.h"
3 #include "quote.h"
4 #include "argv-array.h"
5
6 #if defined(RUNTIME_PREFIX)
7
8 #if defined(HAVE_NS_GET_EXECUTABLE_PATH)
9 #include <mach-o/dyld.h>
10 #endif
11
12 #if defined(HAVE_BSD_KERN_PROC_SYSCTL)
13 #include <sys/param.h>
14 #include <sys/types.h>
15 #include <sys/sysctl.h>
16 #endif
17
18 #endif /* RUNTIME_PREFIX */
19
20 #define MAX_ARGS 32
21
22 static const char *system_prefix(void);
23
24 #ifdef RUNTIME_PREFIX
25
26 /**
27 * When using a runtime prefix, Git dynamically resolves paths relative to its
28 * executable.
29 *
30 * The method for determining the path of the executable is highly
31 * platform-specific.
32 */
33
34 /**
35 * Path to the current Git executable. Resolved on startup by
36 * 'git_resolve_executable_dir'.
37 */
38 static const char *executable_dirname;
39
system_prefix(void)40 static const char *system_prefix(void)
41 {
42 static const char *prefix;
43
44 assert(executable_dirname);
45 assert(is_absolute_path(executable_dirname));
46
47 if (!prefix &&
48 !(prefix = strip_path_suffix(executable_dirname, GIT_EXEC_PATH)) &&
49 !(prefix = strip_path_suffix(executable_dirname, BINDIR)) &&
50 !(prefix = strip_path_suffix(executable_dirname, "git"))) {
51 prefix = FALLBACK_RUNTIME_PREFIX;
52 trace_printf("RUNTIME_PREFIX requested, "
53 "but prefix computation failed. "
54 "Using static fallback '%s'.\n", prefix);
55 }
56 return prefix;
57 }
58
59 /*
60 * Resolves the executable path from argv[0], only if it is absolute.
61 *
62 * Returns 0 on success, -1 on failure.
63 */
git_get_exec_path_from_argv0(struct strbuf * buf,const char * argv0)64 static int git_get_exec_path_from_argv0(struct strbuf *buf, const char *argv0)
65 {
66 const char *slash;
67
68 if (!argv0 || !*argv0)
69 return -1;
70
71 slash = find_last_dir_sep(argv0);
72 if (slash) {
73 trace_printf("trace: resolved executable path from argv0: %s\n",
74 argv0);
75 strbuf_add_absolute_path(buf, argv0);
76 return 0;
77 }
78 return -1;
79 }
80
81 #ifdef PROCFS_EXECUTABLE_PATH
82 /*
83 * Resolves the executable path by examining a procfs symlink.
84 *
85 * Returns 0 on success, -1 on failure.
86 */
git_get_exec_path_procfs(struct strbuf * buf)87 static int git_get_exec_path_procfs(struct strbuf *buf)
88 {
89 if (strbuf_realpath(buf, PROCFS_EXECUTABLE_PATH, 0)) {
90 trace_printf(
91 "trace: resolved executable path from procfs: %s\n",
92 buf->buf);
93 return 0;
94 }
95 return -1;
96 }
97 #endif /* PROCFS_EXECUTABLE_PATH */
98
99 #ifdef HAVE_BSD_KERN_PROC_SYSCTL
100 /*
101 * Resolves the executable path using KERN_PROC_PATHNAME BSD sysctl.
102 *
103 * Returns 0 on success, -1 on failure.
104 */
git_get_exec_path_bsd_sysctl(struct strbuf * buf)105 static int git_get_exec_path_bsd_sysctl(struct strbuf *buf)
106 {
107 int mib[4];
108 char path[MAXPATHLEN];
109 size_t cb = sizeof(path);
110
111 mib[0] = CTL_KERN;
112 mib[1] = KERN_PROC;
113 mib[2] = KERN_PROC_PATHNAME;
114 mib[3] = -1;
115 if (!sysctl(mib, 4, path, &cb, NULL, 0)) {
116 trace_printf(
117 "trace: resolved executable path from sysctl: %s\n",
118 path);
119 strbuf_addstr(buf, path);
120 return 0;
121 }
122 return -1;
123 }
124 #endif /* HAVE_BSD_KERN_PROC_SYSCTL */
125
126 #ifdef HAVE_NS_GET_EXECUTABLE_PATH
127 /*
128 * Resolves the executable path by querying Darwin application stack.
129 *
130 * Returns 0 on success, -1 on failure.
131 */
git_get_exec_path_darwin(struct strbuf * buf)132 static int git_get_exec_path_darwin(struct strbuf *buf)
133 {
134 char path[PATH_MAX];
135 uint32_t size = sizeof(path);
136 if (!_NSGetExecutablePath(path, &size)) {
137 trace_printf(
138 "trace: resolved executable path from Darwin stack: %s\n",
139 path);
140 strbuf_addstr(buf, path);
141 return 0;
142 }
143 return -1;
144 }
145 #endif /* HAVE_NS_GET_EXECUTABLE_PATH */
146
147 #ifdef HAVE_WPGMPTR
148 /*
149 * Resolves the executable path by using the global variable _wpgmptr.
150 *
151 * Returns 0 on success, -1 on failure.
152 */
git_get_exec_path_wpgmptr(struct strbuf * buf)153 static int git_get_exec_path_wpgmptr(struct strbuf *buf)
154 {
155 int len = wcslen(_wpgmptr) * 3 + 1;
156 strbuf_grow(buf, len);
157 len = xwcstoutf(buf->buf, _wpgmptr, len);
158 if (len < 0)
159 return -1;
160 buf->len += len;
161 return 0;
162 }
163 #endif /* HAVE_WPGMPTR */
164
165 /*
166 * Resolves the absolute path of the current executable.
167 *
168 * Returns 0 on success, -1 on failure.
169 */
git_get_exec_path(struct strbuf * buf,const char * argv0)170 static int git_get_exec_path(struct strbuf *buf, const char *argv0)
171 {
172 /*
173 * Identifying the executable path is operating system specific.
174 * Selectively employ all available methods in order of preference,
175 * preferring highly-available authoritative methods over
176 * selectively-available or non-authoritative methods.
177 *
178 * All cases fall back on resolving against argv[0] if there isn't a
179 * better functional method. However, note that argv[0] can be
180 * used-supplied on many operating systems, and is not authoritative
181 * in those cases.
182 *
183 * Each of these functions returns 0 on success, so evaluation will stop
184 * after the first successful method.
185 */
186 if (
187 #ifdef HAVE_BSD_KERN_PROC_SYSCTL
188 git_get_exec_path_bsd_sysctl(buf) &&
189 #endif /* HAVE_BSD_KERN_PROC_SYSCTL */
190
191 #ifdef HAVE_NS_GET_EXECUTABLE_PATH
192 git_get_exec_path_darwin(buf) &&
193 #endif /* HAVE_NS_GET_EXECUTABLE_PATH */
194
195 #ifdef PROCFS_EXECUTABLE_PATH
196 git_get_exec_path_procfs(buf) &&
197 #endif /* PROCFS_EXECUTABLE_PATH */
198
199 #ifdef HAVE_WPGMPTR
200 git_get_exec_path_wpgmptr(buf) &&
201 #endif /* HAVE_WPGMPTR */
202
203 git_get_exec_path_from_argv0(buf, argv0)) {
204 return -1;
205 }
206
207 if (strbuf_normalize_path(buf)) {
208 trace_printf("trace: could not normalize path: %s\n", buf->buf);
209 return -1;
210 }
211
212 trace2_cmd_path(buf->buf);
213
214 return 0;
215 }
216
git_resolve_executable_dir(const char * argv0)217 void git_resolve_executable_dir(const char *argv0)
218 {
219 struct strbuf buf = STRBUF_INIT;
220 char *resolved;
221 const char *slash;
222
223 if (git_get_exec_path(&buf, argv0)) {
224 trace_printf(
225 "trace: could not determine executable path from: %s\n",
226 argv0);
227 strbuf_release(&buf);
228 return;
229 }
230
231 resolved = strbuf_detach(&buf, NULL);
232 slash = find_last_dir_sep(resolved);
233 if (slash)
234 resolved[slash - resolved] = '\0';
235
236 executable_dirname = resolved;
237 trace_printf("trace: resolved executable dir: %s\n",
238 executable_dirname);
239 }
240
241 #else
242
243 /*
244 * When not using a runtime prefix, Git uses a hard-coded path.
245 */
system_prefix(void)246 static const char *system_prefix(void)
247 {
248 return FALLBACK_RUNTIME_PREFIX;
249 }
250
251 /*
252 * This is called during initialization, but No work needs to be done here when
253 * runtime prefix is not being used.
254 */
git_resolve_executable_dir(const char * argv0)255 void git_resolve_executable_dir(const char *argv0)
256 {
257 }
258
259 #endif /* RUNTIME_PREFIX */
260
system_path(const char * path)261 char *system_path(const char *path)
262 {
263 struct strbuf d = STRBUF_INIT;
264
265 if (is_absolute_path(path))
266 return xstrdup(path);
267
268 strbuf_addf(&d, "%s/%s", system_prefix(), path);
269 return strbuf_detach(&d, NULL);
270 }
271
272 static const char *exec_path_value;
273
git_set_exec_path(const char * exec_path)274 void git_set_exec_path(const char *exec_path)
275 {
276 exec_path_value = exec_path;
277 /*
278 * Propagate this setting to external programs.
279 */
280 setenv(EXEC_PATH_ENVIRONMENT, exec_path, 1);
281 }
282
283 /* Returns the highest-priority location to look for git programs. */
git_exec_path(void)284 const char *git_exec_path(void)
285 {
286 if (!exec_path_value) {
287 const char *env = getenv(EXEC_PATH_ENVIRONMENT);
288 if (env && *env)
289 exec_path_value = xstrdup(env);
290 else
291 exec_path_value = system_path(GIT_EXEC_PATH);
292 }
293 return exec_path_value;
294 }
295
add_path(struct strbuf * out,const char * path)296 static void add_path(struct strbuf *out, const char *path)
297 {
298 if (path && *path) {
299 strbuf_add_absolute_path(out, path);
300 strbuf_addch(out, PATH_SEP);
301 }
302 }
303
setup_path(void)304 void setup_path(void)
305 {
306 const char *exec_path = git_exec_path();
307 const char *old_path = getenv("PATH");
308 struct strbuf new_path = STRBUF_INIT;
309
310 git_set_exec_path(exec_path);
311 add_path(&new_path, exec_path);
312
313 if (old_path)
314 strbuf_addstr(&new_path, old_path);
315 else
316 strbuf_addstr(&new_path, _PATH_DEFPATH);
317
318 setenv("PATH", new_path.buf, 1);
319
320 strbuf_release(&new_path);
321 }
322
prepare_git_cmd(struct argv_array * out,const char ** argv)323 const char **prepare_git_cmd(struct argv_array *out, const char **argv)
324 {
325 argv_array_push(out, "git");
326 argv_array_pushv(out, argv);
327 return out->argv;
328 }
329
execv_git_cmd(const char ** argv)330 int execv_git_cmd(const char **argv)
331 {
332 struct argv_array nargv = ARGV_ARRAY_INIT;
333
334 prepare_git_cmd(&nargv, argv);
335 trace_argv_printf(nargv.argv, "trace: exec:");
336
337 /* execvp() can only ever return if it fails */
338 sane_execvp("git", (char **)nargv.argv);
339
340 trace_printf("trace: exec failed: %s\n", strerror(errno));
341
342 argv_array_clear(&nargv);
343 return -1;
344 }
345
execl_git_cmd(const char * cmd,...)346 int execl_git_cmd(const char *cmd, ...)
347 {
348 int argc;
349 const char *argv[MAX_ARGS + 1];
350 const char *arg;
351 va_list param;
352
353 va_start(param, cmd);
354 argv[0] = cmd;
355 argc = 1;
356 while (argc < MAX_ARGS) {
357 arg = argv[argc++] = va_arg(param, char *);
358 if (!arg)
359 break;
360 }
361 va_end(param);
362 if (MAX_ARGS <= argc)
363 return error(_("too many args to run %s"), cmd);
364
365 argv[argc] = NULL;
366 return execv_git_cmd(argv);
367 }
368