root/kernel/init.c

/* */

DEFINITIONS

1. init_trampoline
2. init_init

   1 /*
   2  * fiwix/kernel/init.c
   3  *
   4  * Copyright 2018-2021, Jordi Sanfeliu. All rights reserved.
   5  * Distributed under the terms of the Fiwix License.
   6  */
   7 
   8 #include <fiwix/asm.h>
   9 #include <fiwix/kernel.h>
  10 #include <fiwix/system.h>
  11 #include <fiwix/mm.h>
  12 #include <fiwix/timer.h>
  13 #include <fiwix/sched.h>
  14 #include <fiwix/sleep.h>
  15 #include <fiwix/fcntl.h>
  16 #include <fiwix/stat.h>
  17 #include <fiwix/process.h>
  18 #include <fiwix/syscalls.h>
  19 #include <fiwix/unistd.h>
  20 #include <fiwix/stdio.h>
  21 #include <fiwix/string.h>
  22 
  23 #define INIT_TRAMPOLINE_SIZE    128     /* max. size of init_trampoline() */
  24 
  25 char *init_argv[] = { INIT_PROGRAM, NULL, NULL };
  26 char *init_envp[] = { "HOME=/", "TERM=linux", NULL };
  27 
  28 static void init_trampoline(void)
  29 {
  30         USER_SYSCALL(SYS_open, "/dev/console", O_RDWR, 0);      /* stdin */
  31         USER_SYSCALL(SYS_dup, 0, NULL, NULL);                   /* stdout */
  32         USER_SYSCALL(SYS_dup, 0, NULL, NULL);                   /* stderr */
  33         USER_SYSCALL(SYS_execve, INIT_PROGRAM, init_argv, init_envp);
  34 
  35         /* only reached in case of error in sys_execve() */
  36         USER_SYSCALL(SYS_exit, NULL, NULL, NULL);
  37 }
  38 
  39 void init_init(void)
  40 {
  41         int n;
  42         unsigned int page;
  43         struct inode *i;
  44         unsigned int *pgdir;
  45         struct proc *init;
  46 
  47         if(namei(INIT_PROGRAM, &i, NULL, FOLLOW_LINKS)) {
  48                 PANIC("can't find %s.\n", INIT_PROGRAM);
  49         }
  50         if(!S_ISREG(i->i_mode)) {
  51                 PANIC("%s is not a regular file.\n", INIT_PROGRAM);
  52         }
  53         iput(i);
  54 
  55         /* INIT slot was already created in main.c */
  56         init = &proc_table[INIT];
  57 
  58         /* INIT process starts with the current (kernel) Page Directory */
  59         if(!(pgdir = (void *)kmalloc())) {
  60                 goto init_init__die;
  61         }
  62         init->rss++;
  63         memcpy_b(pgdir, kpage_dir, PAGE_SIZE);
  64         init->tss.cr3 = V2P((unsigned int)pgdir);
  65 
  66         memset_b(init->vma, NULL, sizeof(init->vma));
  67         init->ppid = 0;
  68         init->pgid = 0;
  69         init->sid = 0;
  70         init->flags = 0;
  71         init->children = 0;
  72         init->priority = DEF_PRIORITY;
  73         init->start_time = CURRENT_TICKS;
  74         init->sleep_address = NULL;
  75         init->uid = init->gid = 0;
  76         init->euid = init->egid = 0;
  77         init->suid = init->sgid = 0;
  78         memset_b(init->fd, NULL, sizeof(init->fd));
  79         memset_b(init->fd_flags, NULL, sizeof(init->fd_flags));
  80         init->root = current->root;
  81         init->pwd = current->pwd;
  82         strcpy(init->argv0, init_argv[0]);
  83         init_argv[1] = init_args;
  84         sprintk(init->pidstr, "%d", init->pid);
  85         init->sigpending = 0;
  86         init->sigblocked = 0;
  87         init->sigexecuting = 0;
  88         memset_b(init->sigaction, NULL, sizeof(init->sigaction));
  89         memset_b(&init->usage, NULL, sizeof(struct rusage));
  90         memset_b(&init->cusage, NULL, sizeof(struct rusage));
  91         init->timeout = 0;
  92         for(n = 0; n < RLIM_NLIMITS; n++) {
  93                 init->rlim[n].rlim_cur = init->rlim[n].rlim_max = RLIM_INFINITY;
  94         }
  95         init->rlim[RLIMIT_NOFILE].rlim_cur = OPEN_MAX;
  96         init->rlim[RLIMIT_NOFILE].rlim_max = NR_OPENS;
  97         init->rlim[RLIMIT_NPROC].rlim_cur = CHILD_MAX;
  98         init->rlim[RLIMIT_NPROC].rlim_cur = NR_PROCS;
  99         init->umask = 0022;
 100 
 101         /* setup the stack */
 102         if(!(init->tss.esp0 = kmalloc())) {
 103                 goto init_init__die;
 104         }
 105         init->tss.esp0 += PAGE_SIZE - 4;
 106         init->rss++;
 107         init->tss.ss0 = KERNEL_DS;
 108 
 109         /* setup the init_trampoline */
 110         page = map_page(init, KERNEL_BASE_ADDR - PAGE_SIZE, 0, PROT_READ | PROT_WRITE);
 111         memcpy_b((void *)page, init_trampoline, INIT_TRAMPOLINE_SIZE);
 112 
 113         init->tss.eip = (unsigned int)switch_to_user_mode;
 114         init->tss.esp = page + PAGE_SIZE - 4;
 115 
 116         runnable(init);
 117         nr_processes++;
 118         return;
 119 
 120 init_init__die:
 121         PANIC("unable to run init process.\n");
 122 }

/* */