root/kernel/syscalls/getgroups.c

/* */

DEFINITIONS

1. sys_getgroups

   1 /*
   2  * fiwix/kernel/syscalls/getgroups.c
   3  *
   4  * Copyright 2018, Jordi Sanfeliu. All rights reserved.
   5  * Distributed under the terms of the Fiwix License.
   6  */
   7 
   8 #include <fiwix/types.h>
   9 #include <fiwix/fs.h>
  10 #include <fiwix/process.h>
  11 #include <fiwix/errno.h>
  12 
  13 #ifdef __DEBUG__
  14 #include <fiwix/stdio.h>
  15 #endif /*__DEBUG__ */
  16 
  17 int sys_getgroups(__ssize_t size, __gid_t *list)
  18 {
  19         int n, errno;
  20 
  21 #ifdef __DEBUG__
  22         printk("(pid %d) sys_getgroups(%d, 0x%08x)\n", current->pid, size, (unsigned int)list);
  23 #endif /*__DEBUG__ */
  24 
  25         /*
  26          * If size is 0, sys_getgroups() shall return the number of group IDs
  27          * that it would otherwise return without modifying the array pointed
  28          * to by list.
  29          */
  30         if(!size) {
  31                 for(n = 0; n < NGROUPS_MAX; n++) {
  32                         if(current->groups[n] == -1) {
  33                                 break;
  34                         }
  35                 }
  36                 return n;
  37         }
  38 
  39         if((errno = check_user_area(VERIFY_WRITE, list, sizeof(__gid_t)))) {
  40                 return errno;
  41         }
  42         for(n = 0; n < NGROUPS_MAX; n++) {
  43                 if(current->groups[n] == -1) {
  44                         break;
  45                 }
  46                 if(size) {
  47                         if(n > size) {
  48                                 return -EINVAL;
  49                         }
  50                         list[n] = (__gid_t)current->groups[n];
  51                 }
  52         }
  53         return n;
  54 }

/* */