thisvip/like-posix

builds on top of freertos, providing posix style system calls

like-posix

Builds on top of FreeRTOS, and FatFs by ChaN, providing posix style system calls.

relies upon:

• FatFs by ChaN
• FreeRTOS
• cutensils
• minstdlibs
• the file likeposix_config.h / modified for specific project

system calls

• int open(const char *name, int flags, int mode)
• int close(int file)
• int write(int file, char *buffer, unsigned int count)
• int read(int file, char *buffer, int count)
• int fsync(int file)
• int fstat(int file, struct stat *st)
• int stat(char *file, struct stat *st)
• int isatty(int file)
• int lseek(int file, int offset, int whence)
• int unlink(char *name)
• int rename(const char *oldname, const char *newname)
• char* getcwd(char* buffer, size_t size)
• DIR* opendir(const char *name)
• int closedir(DIR *dirp)
• struct dirent* readdir(DIR *dirp)
• int chdir(const char *path)
• int mkdir(const char *pathname, mode_t mode)
• int gettimeofday(struct timeval *tp, struct timezone *tzp)
• time_t time(time_t* time)
• unsigned int sleep(unsigned int secs)
• int usleep(useconds_t usecs)

** termios calls **

• int tcgetattr(int fildes, struct termios *termios_p)
• int tcsetattr(int fildes, int when, struct termios *termios_p)
• speed_t cfgetispeed(const struct termios* termios)
• speed_t cfgetospeed(const struct termios* termios)
• int cfsetispeed(struct termios* termios, speed_t ispeed)
• int cfsetospeed(struct termios* termios, speed_t ospeed)
• int tcdrain(int file)
• int tcflow(int file, int flags)
• int tcflush(int file, int flags)

lwip based socket api, when enabled*

• int socket(int namespace, int style, int protocol);
• int closesocket(int socket);
• int accept(int socket, struct sockaddr *addr, socklen_t *length_ptr);
• int connect(int socket, struct sockaddr *addr, socklen_t length);
• int bind(int socket, struct sockaddr *addr, socklen_t length);
• int shutdown(int socket, int how);
• int getsockname(int socket, struct sockaddr *addr, socklen_t *length);
• int getpeername(int socket, struct sockaddr *addr, socklen_t *length);
• int setsockopt(int socket, int level, int optname, void *optval, socklen_t optlen);
• int getsockopt(int socket, int level, int optname, void *optval, socklen_t *optlen);
• int listen(int socket, int n);
• int recv(int socket, void *buffer, size_t size, int flags);
• int recvfrom(int socket, void *buffer, size_t size, int flags, struct sockaddr *addr, socklen_t *length);
• int send(int socket, const void *buffer, size_t size, int flags);
• int sendto(int socket, const void *buffer, size_t size, int flags, struct sockaddr *addr, socklen_t length);
• int ioctlsocket(int socket, int cmd, void* argp);
• gethostbyname (directly mapped to lwip_gethostbyname)
• gethostbyname_r (directly mapped to lwip_gethostbyname_r)
• freeaddrinfo (directly mapped to lwip_freeaddrinfo)
• getaddrinfo (directly mapped to lwip_getaddrinfo)

minimal system calls

• void _exit(int i)
• caddr_t _sbrk(int incr)
• int _link(char *old, char *new)
• int _execve(char *name, char **argv, char **env)
• int _fork()
• int _getpid()
• int _kill(int pid, int sig)
• int times(struct tm *buf)
• int _wait(int *status)

stdio

Note, these are implemented in the minstdlibs project.

• FILE* fopen(const char * filename, const char * mode);
• int fclose(FILE* stream);
• int fprintf(FILE* stream, const char * fmt, ...);
• int fputc(int character, FILE* stream);
• int fputs(const char* str, FILE* stream);
• int fgetc(FILE* stream);
• char* fgets(char* str, int num, FILE* stream);
• long int ftell(FILE* stream);
• int fseek(FILE * stream, long int offset, int origin);

sdlib

When linked with like-posix these utilize tyhe FreeRTOS memory API.

• void* malloc(size_t num);
• void* calloc(size_t num, size_t size);
• void* realloc(void* old, size_t newsize);
• void free(void* ptr);

Configuration

the file likeposix_config.h is required at project level, to configure like-posix.

/**
 * sample configuration for the like-posix project.
 */

#ifndef LIKEPOSIX_CONFIG_H_
#define LIKEPOSIX_CONFIG_H_

/**
 * fudge factor for the file table, presently can be any value higher than STDIN_FILENO...
 */
#define FILE_TABLE_OFFSET		10
/**
 * the maximum number of open files/devices
 */
#define FILE_TABLE_LENGTH 		32
/**
 * the maximum number of installed devices, maximum of 255
 */
#define DEVICE_TABLE_LENGTH 	10
/**
 * location where devices get installed to. 
 * this directory is special, dont write regular files here :)
 * it is reserved for devices.
 */
#define DEVICE_INTERFACE_DIRECTORY 	"/dev/"
/**
 * this is a hack that adds an ofset in seconds onto the time returned by time/gettimeofday.
 * corrects time set by NTP for your timezone. 12 hours for NZT
 */
#define TIMEZONE_OFFSET (12 * 60 * 60)
/**
 * enable full integration of lwip sockets in likeposix
 */
#define ENABLE_LIKEPOSIX_SOCKETS    0

#endif /* LIKEPOSIX_CONFIG_H_ */

Base Filesystem

Many projects are better when based on a structured filessystem. like-posix provides a filesytem template that can be installed on an SD card. It is loosely structured, as follows:

• /dev
  • this directory is generated by the system.
  • devices such as serial and USB ports installed here, IO may be performed on them just like normal files.
  • for serial devices the file naming convention will be "ttySx", starting at 0
• /var/log
  • log files are stored here, syslog, bootlog and errorlog for example
• /var/lib/httpd
  • default location for files served by an http server
• /etc/network
  • network configuration files live here: interface, ntp, resolv...
• /etc/logging
  • logging configuration files live here: logging.conf
• /etc/shell
  • shell server configuration files live here: shelld_config
• /etc/echo
  • echo server configuration files live here: echod_config
• /etc/http
  • http server configuration files live here: httpd_config
• /rom
  • firmware images for use by the sdcard bootloader live here