Merge branch 'jk/guard-bswap-header'
[git] / exec-cmd.c
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
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  */
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  */
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  */
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  */
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  */
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  */
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
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  */
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  */
255 void git_resolve_executable_dir(const char *argv0)
256 {
257 }
258
259 #endif /* RUNTIME_PREFIX */
260
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
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. */
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
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
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
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
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
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 }