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_WPGMPTR
 154 /*
 155  * Resolves the executable path by using the global variable _wpgmptr.
 156  *
 157  * Returns 0 on success, -1 on failure.
 158  */
 159 static int git_get_exec_path_wpgmptr(struct strbuf *buf)
 160 {
 161         int len = wcslen(_wpgmptr) * 3 + 1;
 162         strbuf_grow(buf, len);
 163         len = xwcstoutf(buf->buf, _wpgmptr, len);
 164         if (len < 0)
 165                 return -1;
 166         buf->len += len;
 167         return 0;
 168 }
 169 #endif /* HAVE_WPGMPTR */
 170
 171 /*
 172  * Resolves the absolute path of the current executable.
 173  *
 174  * Returns 0 on success, -1 on failure.
 175  */
 176 static int git_get_exec_path(struct strbuf *buf, const char *argv0)
 177 {
 178         /*
 179          * Identifying the executable path is operating system specific.
 180          * Selectively employ all available methods in order of preference,
 181          * preferring highly-available authoritative methods over
 182          * selectively-available or non-authoritative methods.
 183          *
 184          * All cases fall back on resolving against argv[0] if there isn't a
 185          * better functional method. However, note that argv[0] can be
 186          * used-supplied on many operating systems, and is not authoritative
 187          * in those cases.
 188          *
 189          * Each of these functions returns 0 on success, so evaluation will stop
 190          * after the first successful method.
 191          */
 192         if (
 193 #ifdef HAVE_BSD_KERN_PROC_SYSCTL
 194                 git_get_exec_path_bsd_sysctl(buf) &&
 195 #endif /* HAVE_BSD_KERN_PROC_SYSCTL */
 196
 197 #ifdef HAVE_NS_GET_EXECUTABLE_PATH
 198                 git_get_exec_path_darwin(buf) &&
 199 #endif /* HAVE_NS_GET_EXECUTABLE_PATH */
 200
 201 #ifdef PROCFS_EXECUTABLE_PATH
 202                 git_get_exec_path_procfs(buf) &&
 203 #endif /* PROCFS_EXECUTABLE_PATH */
 204
 205 #ifdef HAVE_WPGMPTR
 206                 git_get_exec_path_wpgmptr(buf) &&
 207 #endif /* HAVE_WPGMPTR */
 208
 209                 git_get_exec_path_from_argv0(buf, argv0)) {
 210                 return -1;
 211         }
 212
 213         if (strbuf_normalize_path(buf)) {
 214                 trace_printf("trace: could not normalize path: %s\n", buf->buf);
 215                 return -1;
 216         }
 217
 218         trace2_cmd_path(buf->buf);
 219
 220         return 0;
 221 }
 222
 223 void git_resolve_executable_dir(const char *argv0)
 224 {
 225         struct strbuf buf = STRBUF_INIT;
 226         char *resolved;
 227         const char *slash;
 228
 229         if (git_get_exec_path(&buf, argv0)) {
 230                 trace_printf(
 231                         "trace: could not determine executable path from: %s\n",
 232                         argv0);
 233                 strbuf_release(&buf);
 234                 return;
 235         }
 236
 237         resolved = strbuf_detach(&buf, NULL);
 238         slash = find_last_dir_sep(resolved);
 239         if (slash)
 240                 resolved[slash - resolved] = '\0';
 241
 242         executable_dirname = resolved;
 243         trace_printf("trace: resolved executable dir: %s\n",
 244                      executable_dirname);
 245 }
 246
 247 #else
 248
 249 /*
 250  * When not using a runtime prefix, Git uses a hard-coded path.
 251  */
 252 static const char *system_prefix(void)
 253 {
 254         return FALLBACK_RUNTIME_PREFIX;
 255 }
 256
 257 /*
 258  * This is called during initialization, but No work needs to be done here when
 259  * runtime prefix is not being used.
 260  */
 261 void git_resolve_executable_dir(const char *argv0 UNUSED)
 262 {
 263 }
 264
 265 #endif /* RUNTIME_PREFIX */
 266
 267 char *system_path(const char *path)
 268 {
 269         struct strbuf d = STRBUF_INIT;
 270
 271         if (is_absolute_path(path))
 272                 return xstrdup(path);
 273
 274         strbuf_addf(&d, "%s/%s", system_prefix(), path);
 275         return strbuf_detach(&d, NULL);
 276 }
 277
 278 static const char *exec_path_value;
 279
 280 void git_set_exec_path(const char *exec_path)
 281 {
 282         exec_path_value = exec_path;
 283         /*
 284          * Propagate this setting to external programs.
 285          */
 286         setenv(EXEC_PATH_ENVIRONMENT, exec_path, 1);
 287 }
 288
 289 /* Returns the highest-priority location to look for git programs. */
 290 const char *git_exec_path(void)
 291 {
 292         if (!exec_path_value) {
 293                 const char *env = getenv(EXEC_PATH_ENVIRONMENT);
 294                 if (env && *env)
 295                         exec_path_value = xstrdup(env);
 296                 else
 297                         exec_path_value = system_path(GIT_EXEC_PATH);
 298         }
 299         return exec_path_value;
 300 }
 301
 302 static void add_path(struct strbuf *out, const char *path)
 303 {
 304         if (path && *path) {
 305                 strbuf_add_absolute_path(out, path);
 306                 strbuf_addch(out, PATH_SEP);
 307         }
 308 }
 309
 310 void setup_path(void)
 311 {
 312         const char *exec_path = git_exec_path();
 313         const char *old_path = getenv("PATH");
 314         struct strbuf new_path = STRBUF_INIT;
 315
 316         git_set_exec_path(exec_path);
 317         add_path(&new_path, exec_path);
 318
 319         if (old_path)
 320                 strbuf_addstr(&new_path, old_path);
 321         else
 322                 strbuf_addstr(&new_path, _PATH_DEFPATH);
 323
 324         setenv("PATH", new_path.buf, 1);
 325
 326         strbuf_release(&new_path);
 327 }
 328
 329 const char **prepare_git_cmd(struct strvec *out, const char **argv)
 330 {
 331         strvec_push(out, "git");
 332         strvec_pushv(out, argv);
 333         return out->v;
 334 }
 335
 336 int execv_git_cmd(const char **argv)
 337 {
 338         struct strvec nargv = STRVEC_INIT;
 339
 340         prepare_git_cmd(&nargv, argv);
 341         trace_argv_printf(nargv.v, "trace: exec:");
 342
 343         /* execvp() can only ever return if it fails */
 344         sane_execvp("git", (char **)nargv.v);
 345
 346         trace_printf("trace: exec failed: %s\n", strerror(errno));
 347
 348         strvec_clear(&nargv);
 349         return -1;
 350 }
 351
 352 int execl_git_cmd(const char *cmd, ...)
 353 {
 354         int argc;
 355         const char *argv[MAX_ARGS + 1];
 356         const char *arg;
 357         va_list param;
 358
 359         va_start(param, cmd);
 360         argv[0] = cmd;
 361         argc = 1;
 362         while (argc < MAX_ARGS) {
 363                 arg = argv[argc++] = va_arg(param, char *);
 364                 if (!arg)
 365                         break;
 366         }
 367         va_end(param);
 368         if (MAX_ARGS <= argc)
 369                 return error(_("too many args to run %s"), cmd);
 370
 371         argv[argc] = NULL;
 372         return execv_git_cmd(argv);
 373 }