exec_cmd.con commit tree-diff: avoid alloca for large allocations (b8ba412)
   1#include "cache.h"
   2#include "exec_cmd.h"
   3#include "quote.h"
   4#define MAX_ARGS        32
   5
   6static const char *argv_exec_path;
   7static const char *argv0_path;
   8
   9char *system_path(const char *path)
  10{
  11#ifdef RUNTIME_PREFIX
  12        static const char *prefix;
  13#else
  14        static const char *prefix = PREFIX;
  15#endif
  16        struct strbuf d = STRBUF_INIT;
  17
  18        if (is_absolute_path(path))
  19                return xstrdup(path);
  20
  21#ifdef RUNTIME_PREFIX
  22        assert(argv0_path);
  23        assert(is_absolute_path(argv0_path));
  24
  25        if (!prefix &&
  26            !(prefix = strip_path_suffix(argv0_path, GIT_EXEC_PATH)) &&
  27            !(prefix = strip_path_suffix(argv0_path, BINDIR)) &&
  28            !(prefix = strip_path_suffix(argv0_path, "git"))) {
  29                prefix = PREFIX;
  30                trace_printf("RUNTIME_PREFIX requested, "
  31                                "but prefix computation failed.  "
  32                                "Using static fallback '%s'.\n", prefix);
  33        }
  34#endif
  35
  36        strbuf_addf(&d, "%s/%s", prefix, path);
  37        return strbuf_detach(&d, NULL);
  38}
  39
  40const char *git_extract_argv0_path(const char *argv0)
  41{
  42        const char *slash;
  43
  44        if (!argv0 || !*argv0)
  45                return NULL;
  46        slash = argv0 + strlen(argv0);
  47
  48        while (argv0 <= slash && !is_dir_sep(*slash))
  49                slash--;
  50
  51        if (slash >= argv0) {
  52                argv0_path = xstrndup(argv0, slash - argv0);
  53                return slash + 1;
  54        }
  55
  56        return argv0;
  57}
  58
  59void git_set_argv_exec_path(const char *exec_path)
  60{
  61        argv_exec_path = exec_path;
  62        /*
  63         * Propagate this setting to external programs.
  64         */
  65        setenv(EXEC_PATH_ENVIRONMENT, exec_path, 1);
  66}
  67
  68
  69/* Returns the highest-priority, location to look for git programs. */
  70const char *git_exec_path(void)
  71{
  72        const char *env;
  73
  74        if (argv_exec_path)
  75                return argv_exec_path;
  76
  77        env = getenv(EXEC_PATH_ENVIRONMENT);
  78        if (env && *env) {
  79                return env;
  80        }
  81
  82        return system_path(GIT_EXEC_PATH);
  83}
  84
  85static void add_path(struct strbuf *out, const char *path)
  86{
  87        if (path && *path) {
  88                strbuf_add_absolute_path(out, path);
  89                strbuf_addch(out, PATH_SEP);
  90        }
  91}
  92
  93void setup_path(void)
  94{
  95        const char *old_path = getenv("PATH");
  96        struct strbuf new_path = STRBUF_INIT;
  97
  98        add_path(&new_path, git_exec_path());
  99
 100        if (old_path)
 101                strbuf_addstr(&new_path, old_path);
 102        else
 103                strbuf_addstr(&new_path, _PATH_DEFPATH);
 104
 105        setenv("PATH", new_path.buf, 1);
 106
 107        strbuf_release(&new_path);
 108}
 109
 110const char **prepare_git_cmd(const char **argv)
 111{
 112        int argc;
 113        const char **nargv;
 114
 115        for (argc = 0; argv[argc]; argc++)
 116                ; /* just counting */
 117        nargv = xmalloc(sizeof(*nargv) * (argc + 2));
 118
 119        nargv[0] = "git";
 120        for (argc = 0; argv[argc]; argc++)
 121                nargv[argc + 1] = argv[argc];
 122        nargv[argc + 1] = NULL;
 123        return nargv;
 124}
 125
 126int execv_git_cmd(const char **argv) {
 127        const char **nargv = prepare_git_cmd(argv);
 128        trace_argv_printf(nargv, "trace: exec:");
 129
 130        /* execvp() can only ever return if it fails */
 131        sane_execvp("git", (char **)nargv);
 132
 133        trace_printf("trace: exec failed: %s\n", strerror(errno));
 134
 135        free(nargv);
 136        return -1;
 137}
 138
 139
 140int execl_git_cmd(const char *cmd,...)
 141{
 142        int argc;
 143        const char *argv[MAX_ARGS + 1];
 144        const char *arg;
 145        va_list param;
 146
 147        va_start(param, cmd);
 148        argv[0] = cmd;
 149        argc = 1;
 150        while (argc < MAX_ARGS) {
 151                arg = argv[argc++] = va_arg(param, char *);
 152                if (!arg)
 153                        break;
 154        }
 155        va_end(param);
 156        if (MAX_ARGS <= argc)
 157                return error("too many args to run %s", cmd);
 158
 159        argv[argc] = NULL;
 160        return execv_git_cmd(argv);
 161}