exec-cmd.c

   1 #include "git-compat-util.h"
   2 #include "abspath.h"
   3 #include "environment.h"
   4 #include "exec-cmd.h"
   5 #include "gettext.h"
   6 #include "path.h"
   7 #include "run-command.h"
   8 #include "strvec.h"
   9 #include "trace.h"
  10 #include "trace2.h"
  11
  12 #if defined(RUNTIME_PREFIX)
  13
  14 #if defined(HAVE_NS_GET_EXECUTABLE_PATH)
  15 #include <mach-o/dyld.h>
  16 #endif
  17
  18 #if defined(HAVE_BSD_KERN_PROC_SYSCTL)
  19 #include <sys/param.h>
  20 #include <sys/types.h>
  21 #include <sys/sysctl.h>
  22 #endif
  23
  24 #endif /* RUNTIME_PREFIX */
  25
  26 #define MAX_ARGS 32
  27
  28 static const char *system_prefix(void);
  29
  30 #ifdef RUNTIME_PREFIX
  31
  32 /**
  33  * When using a runtime prefix, Git dynamically resolves paths relative to its
  34  * executable.
  35  *
  36  * The method for determining the path of the executable is highly
  37  * platform-specific.
  38  */
  39
  40 /**
  41  * Path to the current Git executable. Resolved on startup by
  42  * 'git_resolve_executable_dir'.
  43  */
  44 static const char *executable_dirname;
  45
  46 static const char *system_prefix(void)
  47 {
  48         static const char *prefix;
  49
  50         assert(executable_dirname);
  51         assert(is_absolute_path(executable_dirname));
  52
  53         if (!prefix &&
  54             !(prefix = strip_path_suffix(executable_dirname, GIT_EXEC_PATH)) &&
  55             !(prefix = strip_path_suffix(executable_dirname, BINDIR)) &&
  56             !(prefix = strip_path_suffix(executable_dirname, "git"))) {
  57                 prefix = FALLBACK_RUNTIME_PREFIX;
  58                 trace_printf("RUNTIME_PREFIX requested, "
  59                                 "but prefix computation failed.  "
  60                                 "Using static fallback '%s'.\n", prefix);
  61         }
  62         return prefix;
  63 }
  64
  65 /*
  66  * Resolves the executable path from argv[0], only if it is absolute.
  67  *
  68  * Returns 0 on success, -1 on failure.
  69  */
  70 static int git_get_exec_path_from_argv0(struct strbuf *buf, const char *argv0)
  71 {
  72         const char *slash;
  73
  74         if (!argv0 || !*argv0)
  75                 return -1;
  76
  77         slash = find_last_dir_sep(argv0);
  78         if (slash) {
  79                 trace_printf("trace: resolved executable path from argv0: %s\n",
  80                              argv0);
  81                 strbuf_add_absolute_path(buf, argv0);
  82                 return 0;
  83         }
  84         return -1;
  85 }
  86
  87 #ifdef PROCFS_EXECUTABLE_PATH
  88 /*
  89  * Resolves the executable path by examining a procfs symlink.
  90  *
  91  * Returns 0 on success, -1 on failure.
  92  */
  93 static int git_get_exec_path_procfs(struct strbuf *buf)
  94 {
  95         if (strbuf_realpath(buf, PROCFS_EXECUTABLE_PATH, 0)) {
  96                 trace_printf(
  97                         "trace: resolved executable path from procfs: %s\n",
  98                         buf->buf);
  99                 return 0;
 100         }
 101         return -1;
 102 }
 103 #endif /* PROCFS_EXECUTABLE_PATH */
 104
 105 #ifdef HAVE_BSD_KERN_PROC_SYSCTL
 106 /*
 107  * Resolves the executable path using KERN_PROC_PATHNAME BSD sysctl.
 108  *
 109  * Returns 0 on success, -1 on failure.
 110  */
 111 static int git_get_exec_path_bsd_sysctl(struct strbuf *buf)
 112 {
 113         int mib[4];
 114         char path[MAXPATHLEN];
 115         size_t cb = sizeof(path);
 116
 117         mib[0] = CTL_KERN;
 118         mib[1] = KERN_PROC;
 119         mib[2] = KERN_PROC_PATHNAME;
 120         mib[3] = -1;
 121         if (!sysctl(mib, 4, path, &cb, NULL, 0)) {
 122                 trace_printf(
 123                         "trace: resolved executable path from sysctl: %s\n",
 124                         path);
 125                 strbuf_addstr(buf, path);
 126                 return 0;
 127         }
 128         return -1;
 129 }
 130 #endif /* HAVE_BSD_KERN_PROC_SYSCTL */
 131
 132 #ifdef HAVE_NS_GET_EXECUTABLE_PATH
 133 /*
 134  * Resolves the executable path by querying Darwin application stack.
 135  *
 136  * Returns 0 on success, -1 on failure.
 137  */
 138 static int git_get_exec_path_darwin(struct strbuf *buf)
 139 {
 140         char path[PATH_MAX];
 141         uint32_t size = sizeof(path);
 142         if (!_NSGetExecutablePath(path, &size)) {
 143                 trace_printf(
 144                         "trace: resolved executable path from Darwin stack: %s\n",
 145                         path);
 146                 strbuf_addstr(buf, path);
 147                 return 0;
 148         }
 149         return -1;
 150 }
 151 #endif /* HAVE_NS_GET_EXECUTABLE_PATH */
 152
 153 #ifdef HAVE_ZOS_GET_EXECUTABLE_PATH
 154 /*
 155  * Resolves the executable path from current program's directory and name.
 156  *
 157  * Returns 0 on success, -1 on failure.
 158  */
 159 static int git_get_exec_path_zos(struct strbuf *buf)
 160 {
 161         char *dir = __getprogramdir();
 162         char *exe = getprogname();
 163         if (dir && exe) {
 164                 strbuf_addf(buf, "%s/%s", dir, exe);
 165                 return 0;
 166         }
 167         return -1;
 168 }
 169
 170 #endif /* HAVE_ZOS_GET_EXECUTABLE_PATH */
 171
 172 #ifdef HAVE_WPGMPTR
 173 /*
 174  * Resolves the executable path by using the global variable _wpgmptr.
 175  *
 176  * Returns 0 on success, -1 on failure.
 177  */
 178 static int git_get_exec_path_wpgmptr(struct strbuf *buf)
 179 {
 180         int len = wcslen(_wpgmptr) * 3 + 1;
 181         strbuf_grow(buf, len);
 182         len = xwcstoutf(buf->buf, _wpgmptr, len);
 183         if (len < 0)
 184                 return -1;
 185         buf->len += len;
 186         return 0;
 187 }
 188 #endif /* HAVE_WPGMPTR */
 189
 190 /*
 191  * Resolves the absolute path of the current executable.
 192  *
 193  * Returns 0 on success, -1 on failure.
 194  */
 195 static int git_get_exec_path(struct strbuf *buf, const char *argv0)
 196 {
 197         /*
 198          * Identifying the executable path is operating system specific.
 199          * Selectively employ all available methods in order of preference,
 200          * preferring highly-available authoritative methods over
 201          * selectively-available or non-authoritative methods.
 202          *
 203          * All cases fall back on resolving against argv[0] if there isn't a
 204          * better functional method. However, note that argv[0] can be
 205          * used-supplied on many operating systems, and is not authoritative
 206          * in those cases.
 207          *
 208          * Each of these functions returns 0 on success, so evaluation will stop
 209          * after the first successful method.
 210          */
 211         if (
 212 #ifdef HAVE_BSD_KERN_PROC_SYSCTL
 213                 git_get_exec_path_bsd_sysctl(buf) &&
 214 #endif /* HAVE_BSD_KERN_PROC_SYSCTL */
 215
 216 #ifdef HAVE_NS_GET_EXECUTABLE_PATH
 217                 git_get_exec_path_darwin(buf) &&
 218 #endif /* HAVE_NS_GET_EXECUTABLE_PATH */
 219
 220 #ifdef PROCFS_EXECUTABLE_PATH
 221                 git_get_exec_path_procfs(buf) &&
 222 #endif /* PROCFS_EXECUTABLE_PATH */
 223
 224 #ifdef HAVE_WPGMPTR
 225                 git_get_exec_path_wpgmptr(buf) &&
 226 #endif /* HAVE_WPGMPTR */
 227
 228 #ifdef HAVE_ZOS_GET_EXECUTABLE_PATH
 229                 git_get_exec_path_zos(buf) &&
 230 #endif /*HAVE_ZOS_GET_EXECUTABLE_PATH */
 231
 232                 git_get_exec_path_from_argv0(buf, argv0)) {
 233                 return -1;
 234         }
 235
 236         if (strbuf_normalize_path(buf)) {
 237                 trace_printf("trace: could not normalize path: %s\n", buf->buf);
 238                 return -1;
 239         }
 240
 241         trace2_cmd_path(buf->buf);
 242
 243         return 0;
 244 }
 245
 246 void git_resolve_executable_dir(const char *argv0)
 247 {
 248         struct strbuf buf = STRBUF_INIT;
 249         char *resolved;
 250         const char *slash;
 251
 252         if (git_get_exec_path(&buf, argv0)) {
 253                 trace_printf(
 254                         "trace: could not determine executable path from: %s\n",
 255                         argv0);
 256                 strbuf_release(&buf);
 257                 return;
 258         }
 259
 260         resolved = strbuf_detach(&buf, NULL);
 261         slash = find_last_dir_sep(resolved);
 262         if (slash)
 263                 resolved[slash - resolved] = '\0';
 264
 265         executable_dirname = resolved;
 266         trace_printf("trace: resolved executable dir: %s\n",
 267                      executable_dirname);
 268 }
 269
 270 #else
 271
 272 /*
 273  * When not using a runtime prefix, Git uses a hard-coded path.
 274  */
 275 static const char *system_prefix(void)
 276 {
 277         return FALLBACK_RUNTIME_PREFIX;
 278 }
 279
 280 /*
 281  * This is called during initialization, but No work needs to be done here when
 282  * runtime prefix is not being used.
 283  */
 284 void git_resolve_executable_dir(const char *argv0 UNUSED)
 285 {
 286 }
 287
 288 #endif /* RUNTIME_PREFIX */
 289
 290 char *system_path(const char *path)
 291 {
 292         struct strbuf d = STRBUF_INIT;
 293
 294         if (is_absolute_path(path))
 295                 return xstrdup(path);
 296
 297         strbuf_addf(&d, "%s/%s", system_prefix(), path);
 298         return strbuf_detach(&d, NULL);
 299 }
 300
 301 static const char *exec_path_value;
 302
 303 void git_set_exec_path(const char *exec_path)
 304 {
 305         exec_path_value = exec_path;
 306         /*
 307          * Propagate this setting to external programs.
 308          */
 309         setenv(EXEC_PATH_ENVIRONMENT, exec_path, 1);
 310 }
 311
 312 /* Returns the highest-priority location to look for git programs. */
 313 const char *git_exec_path(void)
 314 {
 315         if (!exec_path_value) {
 316                 const char *env = getenv(EXEC_PATH_ENVIRONMENT);
 317                 if (env && *env)
 318                         exec_path_value = xstrdup(env);
 319                 else
 320                         exec_path_value = system_path(GIT_EXEC_PATH);
 321         }
 322         return exec_path_value;
 323 }
 324
 325 static void add_path(struct strbuf *out, const char *path)
 326 {
 327         if (path && *path) {
 328                 strbuf_add_absolute_path(out, path);
 329                 strbuf_addch(out, PATH_SEP);
 330         }
 331 }
 332
 333 void setup_path(void)
 334 {
 335         const char *exec_path = git_exec_path();
 336         const char *old_path = getenv("PATH");
 337         struct strbuf new_path = STRBUF_INIT;
 338
 339         git_set_exec_path(exec_path);
 340         add_path(&new_path, exec_path);
 341
 342         if (old_path)
 343                 strbuf_addstr(&new_path, old_path);
 344         else
 345                 strbuf_addstr(&new_path, _PATH_DEFPATH);
 346
 347         setenv("PATH", new_path.buf, 1);
 348
 349         strbuf_release(&new_path);
 350 }
 351
 352 const char **prepare_git_cmd(struct strvec *out, const char **argv)
 353 {
 354         strvec_push(out, "git");
 355         strvec_pushv(out, argv);
 356         return out->v;
 357 }
 358
 359 int execv_git_cmd(const char **argv)
 360 {
 361         struct strvec nargv = STRVEC_INIT;
 362
 363         prepare_git_cmd(&nargv, argv);
 364         trace_argv_printf(nargv.v, "trace: exec:");
 365
 366         /* execvp() can only ever return if it fails */
 367         sane_execvp("git", (char **)nargv.v);
 368
 369         trace_printf("trace: exec failed: %s\n", strerror(errno));
 370
 371         strvec_clear(&nargv);
 372         return -1;
 373 }
 374
 375 int execl_git_cmd(const char *cmd, ...)
 376 {
 377         int argc;
 378         const char *argv[MAX_ARGS + 1];
 379         const char *arg;
 380         va_list param;
 381
 382         va_start(param, cmd);
 383         argv[0] = cmd;
 384         argc = 1;
 385         while (argc < MAX_ARGS) {
 386                 arg = argv[argc++] = va_arg(param, char *);
 387                 if (!arg)
 388                         break;
 389         }
 390         va_end(param);
 391         if (MAX_ARGS <= argc)
 392                 return error(_("too many args to run %s"), cmd);
 393
 394         argv[argc] = NULL;
 395         return execv_git_cmd(argv);
 396 }