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