sos-code-article10/userland/libc.c

/* Copyright (C) 2005 David Decotigny

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License
   as published by the Free Software Foundation; either version 2
   of the License, or (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
   USA. 
*/

#include "crt.h"
#include "string.h"
#include "stdarg.h"

#include "libc.h"

void exit (int status)
{
  _sos_exit(status);
}


pid_t fork(void)
{
  return _sos_fork();
}


pid_t getpid()
{
  return _sos_getpid();
}


/**
 * Helper to transform the array of argv and envp into an area
 * suitable for the crt.c:unmarshall_argv_envp() function.
 * @see crt.c for the format of this array.
 */
static void const* marshall_execve_parameters(char* const argv[],
					      char* const envp[],
					     /*out*/size_t * sz)
{
  size_t i, i_offset, count_argv, count_envp, size;
  char * str;
  void * result;
  addr_t * offset;

  *sz = 0;

  /* Count the number of argv parameters and the size to allocate */
  for (count_argv = 0, size = 0 ; argv && argv[count_argv] != NULL ; count_argv ++)
    size += strlen(argv[count_argv]) + 1 /* trailing \0 */;

  /* Count the number of envp parameters and the size to allocate */
  for (count_envp = 0 ; envp && envp[count_envp] != NULL ; count_envp ++)
    size += strlen(envp[count_envp]) + 1 /* trailing \0 */;

  size += (count_argv + count_envp + 3) * sizeof(addr_t);
  result = malloc(size);
  if (NULL == result)
    return NULL;

  /* Build the array of offsets and the string contents */
  offset   = (addr_t*)result;
  str      = (char*) & offset[count_argv + count_envp + 3];
  i_offset = 0;

  /* First element of the array is the number of argv entries */
  offset [i_offset++] = count_argv;

  /* Marshall the argv array */
  for (i = 0 ; i < count_argv ; i ++, i_offset ++)
    {
      char const* c;

      offset[i_offset] = (void*)str - result;

      for (c = argv[i] ; *c ; c ++, str ++)
	*str = *c;
      *str = '\0'; str ++;
    }

  /* The NULL between argv and envp */
  offset [i_offset++] = 0;

  for (i = 0 ; i < count_envp ; i ++, i_offset ++)
    {
      char const* c;

      offset[i_offset] = (void*)str - result;

      for (c = envp[i] ; *c ; c ++, str ++)
	*str = *c;
      *str = '\0'; str ++;
    }

  /* Final NULL */
  offset[count_argv + count_envp + 2] = 0;
  *sz = size;

  return result;
}


int execve(const  char  *filename,
	   char  *const argv [],
	   char *const envp[])
{
  void const* args_area;
  size_t args_sz;
  int retval;

  args_area = marshall_execve_parameters(argv, envp, & args_sz);

  retval = _sos_exec(filename,
		     args_area, args_sz);

  if (NULL != args_area)
    free((void*)args_area);

  return retval;
}


int execv(const char  * filename,
	  char  * const argv [])
{
  return execve(filename, argv, environ);
}


static int compute_nargs(va_list ap)
{
  int nargs = 0;
  while (va_arg(ap, char*))
    nargs ++;
  return nargs;
}


static int vexec(const  char  *path, va_list ap, int envp_in_list)
{
  int retval;
  char ** vector, **entry;
  char *str;
  char ** envp;

  size_t nargs = compute_nargs(ap);

  /* Allocate the char* vector */
  vector = malloc((nargs + 1)*sizeof(char*));
  if (! vector)
    return -1;

  /* Fill it */
  entry = vector;
  while ((str = va_arg(ap, char*)) != NULL)
    {
      *entry = str;
      entry ++;
    }
  *entry = NULL;

  if (envp_in_list)
    envp = (char**)va_arg(ap, char*);
  else
    envp = environ;

  retval = execve(path, vector, envp);
  free(vector);
  return retval;
}


int  execl(const  char  *path, ...)
{
  int retval;
  va_list ap;
  va_start(ap, path);
  retval = vexec(path, ap, FALSE);
  va_end(ap);
  return retval;
}


int  execle(const  char  *path, ...)
{
  int retval;
  va_list ap;
  va_start(ap, path);
  retval = vexec(path, ap, TRUE);
  va_end(ap);
  return retval;
}


int exec(char  * const filename)
{
  return execl(filename, filename, NULL);
}


int sleep(unsigned int seconds)
{
  return nanosleep(seconds, 0);
}


int nanosleep(unsigned long int sec,
	      unsigned long int nanosec)
{
  return _sos_nanosleep(sec, nanosec);
}


/**
 * Max number of environment variables
 */
#define SOS_MAX_ENVVARS 1024

char **environ = NULL;


/**
 * Compare the keys of two strings of the form "key=val"
 */
static int equal_key(const char *e1,
		     const char *e2)
{
  for ( ; e1 && (*e1) && e2 && (*e2) && (*e1 == *e2) ; e1++, e2++)
    if (*e1 == '=')
      return TRUE;

  return FALSE;
}


/**
 * Helper function to register an environment variable
 */
static int registerenv(char * string, int can_overwrite)
{
  int i;
  char ** overwritten;

  /* The first time: allocate the environ table */
  if (! environ)
    {
      environ = malloc(SOS_MAX_ENVVARS * sizeof(char*));
      if (! environ)
	return 0;

      memset(environ, 0x0, SOS_MAX_ENVVARS * sizeof(char*));
    }

  /* Walk the environment variables */
  overwritten = NULL;
  for (i = 0 ; i < SOS_MAX_ENVVARS ; i ++)
    {
      /* Reached end of list ? */
      if (! environ[i])
	break;

      /* Variable already present ? */
      if (equal_key(environ[i], string))
	overwritten = & environ[i];
    }

  if (overwritten)
    {
      /* Not allowed to overwrite it ! */
      if (! can_overwrite)
	return -1;

      /* Overwrite allowed: do it now */
      free(*overwritten);
      *overwritten = string;
      return 0;
    }

  /* Must add the variable */

  /* No place left ? */
  if (i >= SOS_MAX_ENVVARS)
    return -1;

  /* Ok, add it at the end */
  environ[i] = string;
  return 0;
}


/**
 * @return TRUE when the key of the "keyvalpair" pair is "key"
 */
static int key_is(char * keyvalpair, const char * key,
		  char ** /*out*/value)
{
  for ( ; keyvalpair && *keyvalpair && key && *key ; keyvalpair ++, key ++)
    if (*key != *keyvalpair)
      break;

  if (value)
    *value = keyvalpair + 1;

  return (keyvalpair && (*keyvalpair == '=') && key && (*key == '\0'));
}


int putenv(char * string)
{
  char * str;
  if (! string)
    return -1;

  str = strdup(string);
  if (! str)
    return -1;

  return registerenv(string, TRUE);
}


int setenv(const char *name, const char *value, int overwrite)
{
  char * str, * c;
  size_t sz_name, sz_value;

  if (!name || !value)
    return -1;

  /* Allocate space for the "name=value" string */
  sz_name = strlen(name);
  sz_value = strlen(value);
  str = malloc(sz_name + 1 + sz_value + 1);
  if (! str)
    return -1;

  /* sprintf(str, "%s=%s", name, value); */
  c = str;
  *c = '\0';
  strzcpy(c, name, sz_name+1); c += sz_name;
  strzcpy(c, "=", 2); c += 1;
  strzcpy(c, value, sz_value+1);

  return registerenv(str, overwrite);
}


char *getenv(const char *name)
{
  int i;

  if (! environ)
    return NULL;

  for (i = 0 ; i < SOS_MAX_ENVVARS ; i ++)
    {
      char *value;

      /* Reached end of list ? */
      if (! environ[i])
	return NULL;

      /* Variable already present ? */
      if (key_is(environ[i], name, & value))
	return value;
    }

  return NULL;
}


void unsetenv(const char *name)
{
  int i;
  char ** entry, ** last_entry;

  if (! environ)
    return;

  /* Walk the environment variables */
  entry = last_entry = NULL;
  for (i = 0 ; i < SOS_MAX_ENVVARS ; i ++)
    {
      /* Reached end of list ? */
      if (! environ[i])
	break;

      /* Variable already present ? */
      if (key_is(environ[i], name, NULL))
	entry = & environ[i];
      else if (entry)
	last_entry = & environ[i];
    }

  /* Found nothing ! */
  if (! entry)
    return;

  /* Found it: erase it... */
  free(*entry);
  *entry = NULL;

  /* ... and replace it with the last entry */
  if (last_entry)
    {
      *entry = *last_entry;
      *last_entry = NULL;
    }
}


int clearenv(void)
{
  int i;

  if (! environ)
    return 0;

  for (i = 0 ; i < SOS_MAX_ENVVARS ; i ++)
    {
      if (! environ[i])
	break;

      free(environ[i]);
      environ[i] = NULL;
    }

  return 0;
}



int munmap(void * start, size_t length)
{
  return _sos_munmap(start, length);
}


void * mremap(void * old_addr, size_t old_len,
	      size_t new_len,
	      unsigned long flags)
{
  void * new_uaddr = old_addr;
  if (0 != _sos_mresize(old_addr, old_len, & new_uaddr, new_len, flags))
    return NULL;

  return new_uaddr;
}


int mprotect(const void *addr, size_t len, int prot)
{
  return _sos_mprotect(addr, len, prot);
}


int msync(void *start, size_t length, int flags)
{
  return _sos_msync(start, length, flags);
}


/**
 * The presence of this global variable without any protected access
 * to it explains why the "brk/sbrk" functions below are MT-unsafe !
 */
static void * kernel_heap_top = NULL;
int brk(void *end_data_seg)
{
  if (! end_data_seg)
    return -1;

  kernel_heap_top = _sos_brk(end_data_seg);
  return 0;
}


void *sbrk(ptrdiff_t increment)
{
  if (! kernel_heap_top)
    kernel_heap_top = _sos_brk(0);

  kernel_heap_top = _sos_brk(kernel_heap_top + increment);
  return kernel_heap_top;
}


void * calloc (size_t nmemb, size_t size)
{
  return malloc(nmemb * size);
}


/**
 * The presence of this global variable without any protected access
 * to it explains why the "malloc/calloc" functions below are
 * MT-unsafe !
 */
static void * malloc_heap_top = NULL;
void * malloc (size_t size)
{
  void * retval;

  if (size <= 0)
    return NULL;

  /* Align on a 4B boundary */
  size = ((size-1) & ~3) + 4;

  if (! kernel_heap_top)
    kernel_heap_top = _sos_brk(0);

  if (! malloc_heap_top)
    malloc_heap_top = kernel_heap_top;

  retval = malloc_heap_top;
  malloc_heap_top += size;

  _sos_brk(malloc_heap_top);
  return retval;
}


void free(void *ptr)
{
  //  bochs_printf("Free ignored (not implemented yet)\n");
}



int mount(const char *source, const char *target,
	  const char *filesystemtype, unsigned long mountflags,
	  const char *data)
{
  return _sos_mount(source, target, filesystemtype, mountflags, data);
}


int umount(const char *target)
{
  return _sos_umount(target);
}


void sync(void)
{
  return _sos_sync();
}


int statvfs(const char *path, struct statvfs *buf)
{
  return _sos_statvfs(path, buf);
}


int open(const char *pathname, int flags, /* mode_t mode */...)
{
  va_list ap;
  unsigned int mode = 0;
 
  va_start(ap, flags);
  if (flags & O_CREAT)
    mode = va_arg(ap, unsigned int);
  va_end(ap);
 
  return _sos_open(pathname, flags, mode);
}


int close(int fd)
{
  return _sos_close(fd);
}


int read(int fd, char * buf, size_t len)
{
  int retval = _sos_read(fd, buf, & len);
  if (retval < 0)
    return retval;
  return len;
}


int write(int fd, const char * buf, size_t len)
{
  int retval = _sos_write(fd, buf, & len);
  if (retval < 0)
    return retval;
  return len;
}


off_t lseek(int fd, off_t offset, int whence)
{
  loff_t result = offset;
  int retval = _sos_seek64(fd, & result, whence);
  if (retval < 0)
    return retval;
  return result;
}


loff_t lseek64(int fd, loff_t offset, int whence)
{
  loff_t result = offset;
  int retval = _sos_seek64(fd, & result, whence);
  if (retval < 0)
    return retval;
  return result;
}


void * mmap(void *start, size_t length, int prot , int flags,
	    int fd, loff_t offset)
{
  /* At kernel side, offset is considered positive */
  if (offset < 0)
    return NULL;

  if (0 != _sos_fmmap(& start, length, prot, flags, fd, offset))
    return NULL;

  return start;
}


int ftruncate(int fd, off_t length)
{
  return _sos_ftruncate64(fd, length);
}


int ftruncate64(int fd, loff_t length)
{
  return _sos_ftruncate64(fd, length);
}


int fcntl(int fd, int cmd, int arg)
{
  return _sos_fcntl(fd, cmd, arg);
}


int ioctl(int fd, int cmd, int arg)
{
  return _sos_ioctl(fd, cmd, arg);
}


int creat(const char *pathname, mode_t mode)
{
  return _sos_creat(pathname, mode);
}

int link (const char *oldpath, const char *newpath)
{
  return _sos_link(oldpath, newpath);
}


int unlink(const char *pathname)
{
  return _sos_unlink(pathname);
}


int rename(const char *oldpath, const char *newpath)
{
  return _sos_rename(oldpath, newpath);
}


int symlink(const char *target, const char *path)
{
  return _sos_symlink(target, path);
}


int mknod(const char *pathname, mode_t mode,
	  int type,
	  unsigned int major, unsigned minor)
{
  if (type == S_IFREG)
    return creat(pathname, mode);
  
  return _sos_mknod(pathname, mode, type,
		    major, minor);
}


int mkdir(const char *pathname, mode_t mode)
{
  return _sos_mkdir(pathname, mode);
}


int rmdir(const char *pathname)
{
  return _sos_rmdir(pathname);
}


int chmod(const char *path, mode_t mode)
{
  return _sos_chmod(path, mode);
}


struct sos_DIR_struct
{
  int fd;
  struct dirent dirent;
};


DIR *opendir(const char *name)
{
  DIR * result = malloc(sizeof(DIR));
  if (! result)
    return NULL;

  result->fd = _sos_open(name, O_DIRECTORY | O_RDONLY, 0);
  return result;
}


int dirfd(const DIR * dir)
{
  if (dir)
    return dir->fd;
  return -1;
}


struct dirent *readdir(DIR *dir)
{
  int retval = _sos_readdir(dir->fd, & dir->dirent);
  if (retval < 0)
    return NULL;
  return & dir->dirent;
}


int closedir(DIR *dir)
{
  close(dir->fd);
  free(dir);
  return 0;
}


int stat(const char *file_name, struct stat *buf)
{
  return _sos_stat(file_name, TRUE, buf);
}


int lstat(const char *file_name, struct stat *buf)
{
  return _sos_stat(file_name, FALSE, buf);
}


int chroot(const char *path)
{
  return _sos_chroot(path);
}


int chdir(const char *path)
{
  return _sos_chdir(path);
}

int fchdir(int fd)
{
  return _sos_fchdir(fd);
}



int printf (const char *format, ...)
{
  char buff[4096];
  va_list ap;

  va_start(ap, format);
  vsnprintf(buff, sizeof(buff), format, ap);
  va_end(ap);

  return write (1, buff, strlen(buff));
}