exec-cmd.c

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