exec_cmd.c

   1 #include "cache.h"
   2 #include "exec_cmd.h"
   3 #define MAX_ARGS        32
   4
   5 extern char **environ;
   6 static const char *builtin_exec_path = GIT_EXEC_PATH;
   7 static const char *current_exec_path = NULL;
   8
   9 void git_set_exec_path(const char *exec_path)
  10 {
  11         current_exec_path = exec_path;
  12 }
  13
  14
  15 /* Returns the highest-priority, location to look for git programs. */
  16 const char *git_exec_path(void)
  17 {
  18         const char *env;
  19
  20         if (current_exec_path)
  21                 return current_exec_path;
  22
  23         env = getenv("GIT_EXEC_PATH");
  24         if (env) {
  25                 return env;
  26         }
  27
  28         return builtin_exec_path;
  29 }
  30
  31
  32 int execv_git_cmd(const char **argv)
  33 {
  34         char git_command[PATH_MAX + 1];
  35         int len, err, i;
  36         const char *paths[] = { current_exec_path,
  37                                 getenv("GIT_EXEC_PATH"),
  38                                 builtin_exec_path };
  39
  40         for (i = 0; i < ARRAY_SIZE(paths); ++i) {
  41                 const char *exec_dir = paths[i];
  42                 const char *tmp;
  43
  44                 if (!exec_dir) continue;
  45
  46                 if (*exec_dir != '/') {
  47                         if (!getcwd(git_command, sizeof(git_command))) {
  48                                 fprintf(stderr, "git: cannot determine "
  49                                         "current directory\n");
  50                                 exit(1);
  51                         }
  52                         len = strlen(git_command);
  53
  54                         /* Trivial cleanup */
  55                         while (!strncmp(exec_dir, "./", 2)) {
  56                                 exec_dir += 2;
  57                                 while (*exec_dir == '/')
  58                                         exec_dir++;
  59                         }
  60                         snprintf(git_command + len, sizeof(git_command) - len,
  61                                  "/%s", exec_dir);
  62                 } else {
  63                         strcpy(git_command, exec_dir);
  64                 }
  65
  66                 len = strlen(git_command);
  67                 len += snprintf(git_command + len, sizeof(git_command) - len,
  68                                 "/git-%s", argv[0]);
  69
  70                 if (sizeof(git_command) <= len) {
  71                         fprintf(stderr,
  72                                 "git: command name given is too long.\n");
  73                         break;
  74                 }
  75
  76                 /* argv[0] must be the git command, but the argv array
  77                  * belongs to the caller, and my be reused in
  78                  * subsequent loop iterations. Save argv[0] and
  79                  * restore it on error.
  80                  */
  81
  82                 tmp = argv[0];
  83                 argv[0] = git_command;
  84
  85                 /* execve() can only ever return if it fails */
  86                 execve(git_command, (char **)argv, environ);
  87
  88                 err = errno;
  89
  90                 argv[0] = tmp;
  91         }
  92         return -1;
  93
  94 }
  95
  96
  97 int execl_git_cmd(const char *cmd,...)
  98 {
  99         int argc;
 100         const char *argv[MAX_ARGS + 1];
 101         const char *arg;
 102         va_list param;
 103
 104         va_start(param, cmd);
 105         argv[0] = cmd;
 106         argc = 1;
 107         while (argc < MAX_ARGS) {
 108                 arg = argv[argc++] = va_arg(param, char *);
 109                 if (!arg)
 110                         break;
 111         }
 112         va_end(param);
 113         if (MAX_ARGS <= argc)
 114                 return error("too many args to run %s", cmd);
 115
 116         argv[argc] = NULL;
 117         return execv_git_cmd(argv);
 118 }