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 && *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 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                 size_t len;
  42                 int rc;
  43                 const char *exec_dir = paths[i];
  44                 const char *tmp;
  45
  46                 if (!exec_dir || !*exec_dir) continue;
  47
  48                 if (*exec_dir != '/') {
  49                         if (!getcwd(git_command, sizeof(git_command))) {
  50                                 fprintf(stderr, "git: cannot determine "
  51                                         "current directory: %s\n",
  52                                         strerror(errno));
  53                                 break;
  54                         }
  55                         len = strlen(git_command);
  56
  57                         /* Trivial cleanup */
  58                         while (!strncmp(exec_dir, "./", 2)) {
  59                                 exec_dir += 2;
  60                                 while (*exec_dir == '/')
  61                                         exec_dir++;
  62                         }
  63
  64                         rc = snprintf(git_command + len,
  65                                       sizeof(git_command) - len, "/%s",
  66                                       exec_dir);
  67                         if (rc < 0 || rc >= sizeof(git_command) - len) {
  68                                 fprintf(stderr, "git: command name given "
  69                                         "is too long.\n");
  70                                 break;
  71                         }
  72                 } else {
  73                         if (strlen(exec_dir) + 1 > sizeof(git_command)) {
  74                                 fprintf(stderr, "git: command name given "
  75                                         "is too long.\n");
  76                                 break;
  77                         }
  78                         strcpy(git_command, exec_dir);
  79                 }
  80
  81                 len = strlen(git_command);
  82                 rc = snprintf(git_command + len, sizeof(git_command) - len,
  83                               "/git-%s", argv[0]);
  84                 if (rc < 0 || rc >= sizeof(git_command) - len) {
  85                         fprintf(stderr,
  86                                 "git: command name given is too long.\n");
  87                         break;
  88                 }
  89
  90                 /* argv[0] must be the git command, but the argv array
  91                  * belongs to the caller, and my be reused in
  92                  * subsequent loop iterations. Save argv[0] and
  93                  * restore it on error.
  94                  */
  95
  96                 tmp = argv[0];
  97                 argv[0] = git_command;
  98
  99                 /* execve() can only ever return if it fails */
 100                 execve(git_command, (char **)argv, environ);
 101
 102                 argv[0] = tmp;
 103         }
 104         return -1;
 105
 106 }
 107
 108
 109 int execl_git_cmd(const char *cmd,...)
 110 {
 111         int argc;
 112         const char *argv[MAX_ARGS + 1];
 113         const char *arg;
 114         va_list param;
 115
 116         va_start(param, cmd);
 117         argv[0] = cmd;
 118         argc = 1;
 119         while (argc < MAX_ARGS) {
 120                 arg = argv[argc++] = va_arg(param, char *);
 121                 if (!arg)
 122                         break;
 123         }
 124         va_end(param);
 125         if (MAX_ARGS <= argc)
 126                 return error("too many args to run %s", cmd);
 127
 128         argv[argc] = NULL;
 129         return execv_git_cmd(argv);
 130 }