Andrew's git - gitweb.git/blob

   1#include "cache.h"
   2#include "exec_cmd.h"
   3#include "quote.h"
   4#include "argv-array.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
  22static 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 */
  38static const char *executable_dirname;
  39
  40static 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 = 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 */
  64static 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 */
  87static 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 */
 105static 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 */
 132static 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/*
 148 * Resolves the absolute path of the current executable.
 149 *
 150 * Returns 0 on success, -1 on failure.
 151 */
 152static int git_get_exec_path(struct strbuf *buf, const char *argv0)
 153{
 154        /*
 155         * Identifying the executable path is operating system specific.
 156         * Selectively employ all available methods in order of preference,
 157         * preferring highly-available authoritative methods over
 158         * selectively-available or non-authoritative methods.
 159         *
 160         * All cases fall back on resolving against argv[0] if there isn't a
 161         * better functional method. However, note that argv[0] can be
 162         * used-supplied on many operating systems, and is not authoritative
 163         * in those cases.
 164         *
 165         * Each of these functions returns 0 on success, so evaluation will stop
 166         * after the first successful method.
 167         */
 168        if (
 169#ifdef HAVE_BSD_KERN_PROC_SYSCTL
 170                git_get_exec_path_bsd_sysctl(buf) &&
 171#endif /* HAVE_BSD_KERN_PROC_SYSCTL */
 172
 173#ifdef HAVE_NS_GET_EXECUTABLE_PATH
 174                git_get_exec_path_darwin(buf) &&
 175#endif /* HAVE_NS_GET_EXECUTABLE_PATH */
 176
 177#ifdef PROCFS_EXECUTABLE_PATH
 178                git_get_exec_path_procfs(buf) &&
 179#endif /* PROCFS_EXECUTABLE_PATH */
 180
 181                git_get_exec_path_from_argv0(buf, argv0)) {
 182                return -1;
 183        }
 184
 185        if (strbuf_normalize_path(buf)) {
 186                trace_printf("trace: could not normalize path: %s\n", buf->buf);
 187                return -1;
 188        }
 189
 190        return 0;
 191}
 192
 193void git_resolve_executable_dir(const char *argv0)
 194{
 195        struct strbuf buf = STRBUF_INIT;
 196        char *resolved;
 197        const char *slash;
 198
 199        if (git_get_exec_path(&buf, argv0)) {
 200                trace_printf(
 201                        "trace: could not determine executable path from: %s\n",
 202                        argv0);
 203                strbuf_release(&buf);
 204                return;
 205        }
 206
 207        resolved = strbuf_detach(&buf, NULL);
 208        slash = find_last_dir_sep(resolved);
 209        if (slash)
 210                resolved[slash - resolved] = '\0';
 211
 212        executable_dirname = resolved;
 213        trace_printf("trace: resolved executable dir: %s\n",
 214                     executable_dirname);
 215}
 216
 217#else
 218
 219/*
 220 * When not using a runtime prefix, Git uses a hard-coded path.
 221 */
 222static const char *system_prefix(void)
 223{
 224        return PREFIX;
 225}
 226
 227/*
 228 * This is called during initialization, but No work needs to be done here when
 229 * runtime prefix is not being used.
 230 */
 231void git_resolve_executable_dir(const char *argv0)
 232{
 233}
 234
 235#endif /* RUNTIME_PREFIX */
 236
 237char *system_path(const char *path)
 238{
 239        struct strbuf d = STRBUF_INIT;
 240
 241        if (is_absolute_path(path))
 242                return xstrdup(path);
 243
 244        strbuf_addf(&d, "%s/%s", system_prefix(), path);
 245        return strbuf_detach(&d, NULL);
 246}
 247
 248static const char *exec_path_value;
 249
 250void git_set_exec_path(const char *exec_path)
 251{
 252        exec_path_value = exec_path;
 253        /*
 254         * Propagate this setting to external programs.
 255         */
 256        setenv(EXEC_PATH_ENVIRONMENT, exec_path, 1);
 257}
 258
 259/* Returns the highest-priority location to look for git programs. */
 260const char *git_exec_path(void)
 261{
 262        if (!exec_path_value) {
 263                const char *env = getenv(EXEC_PATH_ENVIRONMENT);
 264                if (env && *env)
 265                        exec_path_value = xstrdup(env);
 266                else
 267                        exec_path_value = system_path(GIT_EXEC_PATH);
 268        }
 269        return exec_path_value;
 270}
 271
 272static void add_path(struct strbuf *out, const char *path)
 273{
 274        if (path && *path) {
 275                strbuf_add_absolute_path(out, path);
 276                strbuf_addch(out, PATH_SEP);
 277        }
 278}
 279
 280void setup_path(void)
 281{
 282        const char *exec_path = git_exec_path();
 283        const char *old_path = getenv("PATH");
 284        struct strbuf new_path = STRBUF_INIT;
 285
 286        git_set_exec_path(exec_path);
 287        add_path(&new_path, exec_path);
 288
 289        if (old_path)
 290                strbuf_addstr(&new_path, old_path);
 291        else
 292                strbuf_addstr(&new_path, _PATH_DEFPATH);
 293
 294        setenv("PATH", new_path.buf, 1);
 295
 296        strbuf_release(&new_path);
 297}
 298
 299const char **prepare_git_cmd(struct argv_array *out, const char **argv)
 300{
 301        argv_array_push(out, "git");
 302        argv_array_pushv(out, argv);
 303        return out->argv;
 304}
 305
 306int execv_git_cmd(const char **argv)
 307{
 308        struct argv_array nargv = ARGV_ARRAY_INIT;
 309
 310        prepare_git_cmd(&nargv, argv);
 311        trace_argv_printf(nargv.argv, "trace: exec:");
 312
 313        /* execvp() can only ever return if it fails */
 314        sane_execvp("git", (char **)nargv.argv);
 315
 316        trace_printf("trace: exec failed: %s\n", strerror(errno));
 317
 318        argv_array_clear(&nargv);
 319        return -1;
 320}
 321
 322int execl_git_cmd(const char *cmd, ...)
 323{
 324        int argc;
 325        const char *argv[MAX_ARGS + 1];
 326        const char *arg;
 327        va_list param;
 328
 329        va_start(param, cmd);
 330        argv[0] = cmd;
 331        argc = 1;
 332        while (argc < MAX_ARGS) {
 333                arg = argv[argc++] = va_arg(param, char *);
 334                if (!arg)
 335                        break;
 336        }
 337        va_end(param);
 338        if (MAX_ARGS <= argc)
 339                return error("too many args to run %s", cmd);
 340
 341        argv[argc] = NULL;
 342        return execv_git_cmd(argv);
 343}