Andrew's git / gitweb.git / exec-cmd.c
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exec-cmd.con commit hex: switch to using the_hash_algo (d9cd734)
   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 = 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 */
  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#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 */
 153static 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 */
 170static 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        return 0;
 213}
 214
 215void git_resolve_executable_dir(const char *argv0)
 216{
 217        struct strbuf buf = STRBUF_INIT;
 218        char *resolved;
 219        const char *slash;
 220
 221        if (git_get_exec_path(&buf, argv0)) {
 222                trace_printf(
 223                        "trace: could not determine executable path from: %s\n",
 224                        argv0);
 225                strbuf_release(&buf);
 226                return;
 227        }
 228
 229        resolved = strbuf_detach(&buf, NULL);
 230        slash = find_last_dir_sep(resolved);
 231        if (slash)
 232                resolved[slash - resolved] = '\0';
 233
 234        executable_dirname = resolved;
 235        trace_printf("trace: resolved executable dir: %s\n",
 236                     executable_dirname);
 237}
 238
 239#else
 240
 241/*
 242 * When not using a runtime prefix, Git uses a hard-coded path.
 243 */
 244static const char *system_prefix(void)
 245{
 246        return FALLBACK_RUNTIME_PREFIX;
 247}
 248
 249/*
 250 * This is called during initialization, but No work needs to be done here when
 251 * runtime prefix is not being used.
 252 */
 253void git_resolve_executable_dir(const char *argv0)
 254{
 255}
 256
 257#endif /* RUNTIME_PREFIX */
 258
 259char *system_path(const char *path)
 260{
 261        struct strbuf d = STRBUF_INIT;
 262
 263        if (is_absolute_path(path))
 264                return xstrdup(path);
 265
 266        strbuf_addf(&d, "%s/%s", system_prefix(), path);
 267        return strbuf_detach(&d, NULL);
 268}
 269
 270static const char *exec_path_value;
 271
 272void git_set_exec_path(const char *exec_path)
 273{
 274        exec_path_value = exec_path;
 275        /*
 276         * Propagate this setting to external programs.
 277         */
 278        setenv(EXEC_PATH_ENVIRONMENT, exec_path, 1);
 279}
 280
 281/* Returns the highest-priority location to look for git programs. */
 282const char *git_exec_path(void)
 283{
 284        if (!exec_path_value) {
 285                const char *env = getenv(EXEC_PATH_ENVIRONMENT);
 286                if (env && *env)
 287                        exec_path_value = xstrdup(env);
 288                else
 289                        exec_path_value = system_path(GIT_EXEC_PATH);
 290        }
 291        return exec_path_value;
 292}
 293
 294static void add_path(struct strbuf *out, const char *path)
 295{
 296        if (path && *path) {
 297                strbuf_add_absolute_path(out, path);
 298                strbuf_addch(out, PATH_SEP);
 299        }
 300}
 301
 302void setup_path(void)
 303{
 304        const char *exec_path = git_exec_path();
 305        const char *old_path = getenv("PATH");
 306        struct strbuf new_path = STRBUF_INIT;
 307
 308        git_set_exec_path(exec_path);
 309        add_path(&new_path, exec_path);
 310
 311        if (old_path)
 312                strbuf_addstr(&new_path, old_path);
 313        else
 314                strbuf_addstr(&new_path, _PATH_DEFPATH);
 315
 316        setenv("PATH", new_path.buf, 1);
 317
 318        strbuf_release(&new_path);
 319}
 320
 321const char **prepare_git_cmd(struct argv_array *out, const char **argv)
 322{
 323        argv_array_push(out, "git");
 324        argv_array_pushv(out, argv);
 325        return out->argv;
 326}
 327
 328int execv_git_cmd(const char **argv)
 329{
 330        struct argv_array nargv = ARGV_ARRAY_INIT;
 331
 332        prepare_git_cmd(&nargv, argv);
 333        trace_argv_printf(nargv.argv, "trace: exec:");
 334
 335        /* execvp() can only ever return if it fails */
 336        sane_execvp("git", (char **)nargv.argv);
 337
 338        trace_printf("trace: exec failed: %s\n", strerror(errno));
 339
 340        argv_array_clear(&nargv);
 341        return -1;
 342}
 343
 344int execl_git_cmd(const char *cmd, ...)
 345{
 346        int argc;
 347        const char *argv[MAX_ARGS + 1];
 348        const char *arg;
 349        va_list param;
 350
 351        va_start(param, cmd);
 352        argv[0] = cmd;
 353        argc = 1;
 354        while (argc < MAX_ARGS) {
 355                arg = argv[argc++] = va_arg(param, char *);
 356                if (!arg)
 357                        break;
 358        }
 359        va_end(param);
 360        if (MAX_ARGS <= argc)
 361                return error("too many args to run %s", cmd);
 362
 363        argv[argc] = NULL;
 364        return execv_git_cmd(argv);
 365}