syscall.h File Reference

#include <arpa/inet.h>
#include <errno.h>
#include <stdint.h>
#include <stdio.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>

Include dependency graph for syscall.h:

This graph shows which files directly or indirectly include this file:

Functions
int	test (const char *s)
ssize_t	write (int fd, const void *buf, size_t count)
ssize_t	read (int fd, void *buf, size_t count)
int	fstat (int fd, struct stat *statbuf)
off_t	lseek (int fd, off_t offset, int whence)
int	gettimeofday (struct timeval *p, void *z)
int	open (const char *pathname, uint32_t flags)
int	close (int fd)
int	reboot (int command)
int	socket (int domain, int type, int protocol)
ssize_t	sendto (int sockfd, const void *buf, size_t len, int flags, const struct sockaddr *dst_addr, socklen_t addrlen)
ssize_t	recvfrom (int sockfd, void *buf, size_t len, int flags, struct sockaddr *src_addr, socklen_t *addrlen)
int	gethostbyname2 (const char *name, struct in_addr *in)
int	execv (const char *path, char *const argv[])
pid_t	getpid ()
void	exit (int code)
int	openat (int dirfd, const char *pathname, int flags)

Function Documentation

close()

int close

(

int

fd

)

Implements the close syscall.

Parameters

fd	a file descriptor ID

Returns

zero on success, -1 otherwise

execv()

int execv	(	const char *	path,
		char *const	argv[] )

Implements the execv syscall.

Parameters

path	the name of a file that is to be executed
argv	a list of one or more pointers to null-terminated strings that represent the argument list available to the executed program

Returns

only return if an error has occurred

exit()

void exit

(

int

code

)

Implements the exit syscall.

Parameters

code	the status code

fstat()

int fstat	(	int	fd,
		struct stat *	statbuf )

Implements the fstat syscall.

Parameters

fd	a file descriptor ID
statbuf	a stat structure

Returns

0 on success or -1 in case of an error

gethostbyname2()

int gethostbyname2	(	const char *	name,
		struct in_addr *	in )

Implements the gethostbyname2 syscall. Most existing systems don't have such a syscall but we do and it performs a DNS lookup.

Parameters

name	a hostname
in	the receiving Internet address

Returns

0 on success, a non-zero value otherwise

getpid()

pid_t getpid

(

)

Implements the getpid syscall.

Returns

the process ID (PID) of the calling process

gettimeofday()

int gettimeofday	(	struct timeval *	p,
		void *	z )

Implements the gettimeofday syscall.

lseek()

off_t lseek	(	int	fd,
		off_t	offset,
		int	whence )

Implements the lseek syscall.

Parameters

fd	a file descriptor ID
offset	the offset value
whence	a directive to reposition the offset

Returns

the value of the offset on success or -1 in case of an error

open()

int open	(	const char *	pathname,
		uint32_t	flags )

Implements the open syscall.

Parameters

pathname	the name of the file to open
flags	creation or file status flags

Returns

a file descriptor, i.e. a small, non-negative integer that is used in subsequent system calls

openat()

int openat	(	int	dirfd,
		const char *	pathname,
		int	flags )

Implements the openat syscall.

Parameters

dirfd	a directory file descriptor
pathname	the name of the file to open
flags	creation or file status flags

Returns

a file descriptor, i.e. a small, non-negative integer that is used in subsequent system calls

read()

ssize_t read	(	int	fd,
		void *	buf,
		size_t	count )

Implements the read syscall. read() attempts to read up to count bytes from file descriptor fd into the buffer starting at buf.

Parameters

fd	a file descriptor ID
buf	a buffer that receives the bytes read
count	the maximum number of bytes to read

Returns

the actual number of bytes read or -1 in case of an error

reboot()

int reboot

(

int

command

)

Implements the reboot syscall.

Parameters

command

a reboot command

Returns

when command is REBOOT_CMD_RESTART, it does not return. -1 is returned in case of an error, 0 otherwise.

recvfrom()

ssize_t recvfrom	(	int	sockfd,
		void *	buf,
		size_t	len,
		int	flags,
		struct sockaddr *	src_addr,
		socklen_t *	addrlen )

Implements the recvfrom syscall.

Parameters

sockfd	socket descriptor ID
buf	the receiving buffer
len	the size of the receiving buffer
flags	some flags
src_addr	the address of the sender
addrlen	the size of the sender address structure

Returns

the number of bytes actually received

sendto()

ssize_t sendto	(	int	sockfd,
		const void *	buf,
		size_t	len,
		int	flags,
		const struct sockaddr *	dst_addr,
		socklen_t	addrlen )

Implements the sendto syscall.

Parameters

sockfd	socket descriptor ID
buf	the data to send
len	the length of the data to send
flags	some flags
dst_addr	the destination address
addrlen	the size of the destination address structure

Returns

the number of bytes sent to the destination

socket()

int socket	(	int	domain,
		int	type,
		int	protocol )

Implements the socket syscall.

Parameters

domain	the communication domain (we only support AF_INET so far)
type	the communication semantics (we only support SOCK_DGRAM so far)
protocol	the particular protocol to be used with the socket

Returns

a file descriptor on success, -1 otherwise

test()

int test

(

const char *

s

)

Implements a syscall for testing purpose only. It takes a string as input and prints it to the screen.

Parameters

s	a string to print on the screen

Returns

the return value should always be 42

write()

ssize_t write	(	int	fd,
		const void *	buf,
		size_t	count )

Implements the write syscall.

Parameters

fd	a file descriptor ID
buf	a buffer that contains the bytes to write
count	the maximum number of bytes to write

Returns

the actual number of bytes write or -1 in case of an error