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