exec-cmd.c

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