exec_cmd.c

   1 #include "cache.h"
   2 #include "exec_cmd.h"
   3 #include "quote.h"
   4 #define MAX_ARGS        32
   5
   6 extern char **environ;
   7 static const char *builtin_exec_path = GIT_EXEC_PATH;
   8 static const char *current_exec_path;
   9
  10 void git_set_exec_path(const char *exec_path)
  11 {
  12         current_exec_path = exec_path;
  13 }
  14
  15
  16 /* Returns the highest-priority, location to look for git programs. */
  17 const char *git_exec_path(void)
  18 {
  19         const char *env;
  20
  21         if (current_exec_path)
  22                 return current_exec_path;
  23
  24         env = getenv(EXEC_PATH_ENVIRONMENT);
  25         if (env && *env) {
  26                 return env;
  27         }
  28
  29         return builtin_exec_path;
  30 }
  31
  32
  33 int execv_git_cmd(const char **argv)
  34 {
  35         char git_command[PATH_MAX + 1];
  36         int i;
  37         const char *paths[] = { current_exec_path,
  38                                 getenv(EXEC_PATH_ENVIRONMENT),
  39                                 builtin_exec_path };
  40
  41         for (i = 0; i < ARRAY_SIZE(paths); ++i) {
  42                 size_t len;
  43                 int rc;
  44                 const char *exec_dir = paths[i];
  45                 const char *tmp;
  46
  47                 if (!exec_dir || !*exec_dir) continue;
  48
  49                 if (*exec_dir != '/') {
  50                         if (!getcwd(git_command, sizeof(git_command))) {
  51                                 fprintf(stderr, "git: cannot determine "
  52                                         "current directory: %s\n",
  53                                         strerror(errno));
  54                                 break;
  55                         }
  56                         len = strlen(git_command);
  57
  58                         /* Trivial cleanup */
  59                         while (!prefixcmp(exec_dir, "./")) {
  60                                 exec_dir += 2;
  61                                 while (*exec_dir == '/')
  62                                         exec_dir++;
  63                         }
  64
  65                         rc = snprintf(git_command + len,
  66                                       sizeof(git_command) - len, "/%s",
  67                                       exec_dir);
  68                         if (rc < 0 || rc >= sizeof(git_command) - len) {
  69                                 fprintf(stderr, "git: command name given "
  70                                         "is too long.\n");
  71                                 break;
  72                         }
  73                 } else {
  74                         if (strlen(exec_dir) + 1 > sizeof(git_command)) {
  75                                 fprintf(stderr, "git: command name given "
  76                                         "is too long.\n");
  77                                 break;
  78                         }
  79                         strcpy(git_command, exec_dir);
  80                 }
  81
  82                 len = strlen(git_command);
  83                 rc = snprintf(git_command + len, sizeof(git_command) - len,
  84                               "/git-%s", argv[0]);
  85                 if (rc < 0 || rc >= sizeof(git_command) - len) {
  86                         fprintf(stderr,
  87                                 "git: command name given is too long.\n");
  88                         break;
  89                 }
  90
  91                 /* argv[0] must be the git command, but the argv array
  92                  * belongs to the caller, and my be reused in
  93                  * subsequent loop iterations. Save argv[0] and
  94                  * restore it on error.
  95                  */
  96
  97                 tmp = argv[0];
  98                 argv[0] = git_command;
  99
 100                 trace_argv_printf(argv, -1, "trace: exec:");
 101
 102                 /* execve() can only ever return if it fails */
 103                 execve(git_command, (char **)argv, environ);
 104
 105                 trace_printf("trace: exec failed: %s\n", strerror(errno));
 106
 107                 argv[0] = tmp;
 108         }
 109         return -1;
 110
 111 }
 112
 113
 114 int execl_git_cmd(const char *cmd,...)
 115 {
 116         int argc;
 117         const char *argv[MAX_ARGS + 1];
 118         const char *arg;
 119         va_list param;
 120
 121         va_start(param, cmd);
 122         argv[0] = cmd;
 123         argc = 1;
 124         while (argc < MAX_ARGS) {
 125                 arg = argv[argc++] = va_arg(param, char *);
 126                 if (!arg)
 127                         break;
 128         }
 129         va_end(param);
 130         if (MAX_ARGS <= argc)
 131                 return error("too many args to run %s", cmd);
 132
 133         argv[argc] = NULL;
 134         return execv_git_cmd(argv);
 135 }