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(char **argv)
  33 {
  34         char git_command[PATH_MAX + 1];
  35         char *tmp;
  36         int len, err, i;
  37         const char *paths[] = { current_exec_path,
  38                                 getenv("GIT_EXEC_PATH"),
  39                                 builtin_exec_path };
  40
  41         for (i = 0; i < sizeof(paths)/sizeof(paths[0]); ++i) {
  42                 const char *exec_dir = paths[i];
  43                 if (!exec_dir) continue;
  44
  45                 if (*exec_dir != '/') {
  46                         if (!getcwd(git_command, sizeof(git_command))) {
  47                                 fprintf(stderr, "git: cannot determine "
  48                                         "current directory\n");
  49                                 exit(1);
  50                         }
  51                         len = strlen(git_command);
  52
  53                         /* Trivial cleanup */
  54                         while (!strncmp(exec_dir, "./", 2)) {
  55                                 exec_dir += 2;
  56                                 while (*exec_dir == '/')
  57                                         exec_dir++;
  58                         }
  59                         snprintf(git_command + len, sizeof(git_command) - len,
  60                                  "/%s", exec_dir);
  61                 } else {
  62                         strcpy(git_command, exec_dir);
  63                 }
  64
  65                 len = strlen(git_command);
  66                 len += snprintf(git_command + len, sizeof(git_command) - len,
  67                                 "/git-%s", argv[0]);
  68
  69                 if (sizeof(git_command) <= len) {
  70                         fprintf(stderr,
  71                                 "git: command name given is too long.\n");
  72                         break;
  73                 }
  74
  75                 /* argv[0] must be the git command, but the argv array
  76                  * belongs to the caller, and my be reused in
  77                  * subsequent loop iterations. Save argv[0] and
  78                  * restore it on error.
  79                  */
  80
  81                 tmp = argv[0];
  82                 argv[0] = git_command;
  83
  84                 /* execve() can only ever return if it fails */
  85                 execve(git_command, argv, environ);
  86
  87                 err = errno;
  88
  89                 argv[0] = tmp;
  90         }
  91         return -1;
  92
  93 }
  94
  95
  96 int execl_git_cmd(char *cmd,...)
  97 {
  98         int argc;
  99         char *argv[MAX_ARGS + 1];
 100         char *arg;
 101         va_list param;
 102
 103         va_start(param, cmd);
 104         argv[0] = cmd;
 105         argc = 1;
 106         while (argc < MAX_ARGS) {
 107                 arg = argv[argc++] = va_arg(param, char *);
 108                 if (!arg)
 109                         break;
 110         }
 111         va_end(param);
 112         if (MAX_ARGS <= argc)
 113                 return error("too many args to run %s", cmd);
 114
 115         argv[argc] = NULL;
 116         return execv_git_cmd(argv);
 117 }