fs/exec.c

   1 /*
   2  * The thunix execve system call implementaion
   3  */
   4 #include <stdio.h>
   5 #include <string.h>
   6 #include <malloc.h>
   7 #include <fs.h>
   8 #include <err.h>
   9
  10
  11 /*
  12  * Count how many arguments we hare
  13  */
  14 static inline int count(char **argv)
  15 {
  16         int i = 0;
  17         if (argv) {
  18                 while (argv[i])
  19                         i++;
  20         }
  21         return i;
  22 }
  23
  24 int sys_execve(const char *file, char **argv)
  25 {
  26         int fd = sys_open(file, 0);
  27
  28         /*
  29          * The current exec plan is: load the binary file to 16M,
  30          * then jump to this address.
  31          *
  32          * I will try to make a good global thunix memory allocation
  33          * map when I get time.
  34          */
  35         char * exec_buf = (char *)0x1600000;
  36         char *p = exec_buf;
  37         int bytes_read;
  38         int argc;
  39         int (*entry)(int, char **);
  40
  41         if (fd < 0)
  42                 return fd;
  43
  44         /*
  45          * Try to read 4K at a time
  46          *
  47          * Note: Since we don't support demand loading now, the current exec plan is
  48          * to load the whole program into
  49          * memory once.
  50          */
  51         while ((bytes_read = sys_read(fd, p, 4096)) > 0)
  52                 p += bytes_read;
  53         sys_close(fd);
  54
  55         argc = count(argv);
  56
  57         entry = (int(*)(int, char **))(exec_buf);
  58         return entry(argc, argv);
  59 }