unistd.c

   1 #include <time.h>
   2 #include <stdarg.h>
   3 #include <string.h>
   4 #include <unistd.h>
   5
   6 int sleep(int n)
   7 {
   8         struct timespec req = {n, 0};
   9         struct timespec rem;
  10         if (nanosleep(&req, &rem))
  11                 return rem.tv_sec;
  12         return 0;
  13 }
  14
  15 #define EXECARGS        (1 << 7)
  16
  17 int execle(char *path, ...)
  18 {
  19         va_list ap;
  20         char *argv[EXECARGS];
  21         char **envp;
  22         int argc = 0;
  23         va_start(ap, path);
  24         while (argc + 1 < EXECARGS && (argv[argc] = va_arg(ap, char *)))
  25                 argc++;
  26         envp = va_arg(ap, char **);
  27         va_end(ap);
  28         argv[argc] = NULL;
  29         execve(path, argv, envp);
  30         return -1;
  31 }
  32
  33 int execvp(char *cmd, char *argv[])
  34 {
  35         char path[512];
  36         char *p = getenv("PATH");
  37         if (strchr(cmd, '/'))
  38                 return execve(cmd, argv, environ);
  39         if (!p)
  40                 p = "/bin";
  41         while (*p) {
  42                 char *s = path;
  43                 while (*p && *p != ':')
  44                         *s++ = *p++;
  45                 if (s != path)
  46                         *s++ = '/';
  47                 strcpy(s, cmd);
  48                 execve(path, argv, environ);
  49                 if (*p == ':')
  50                         p++;
  51         }
  52         return -1;
  53 }
  54
  55 int wait(int *status)
  56 {
  57         return waitpid(-1, status, 0);
  58 }