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#include "osm/bind.h"
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/un.h>
/**
* The required characters to represent an id as a file name
* id - the id to get translated to a file name
*/
int _need_chars(int id)
{
int i = 1;
while (id > 15)
{
id /= 16;
i++;
}
return i;
}
/**
* Write the integer file name after the folder path.
* id - the id to get translated to a file name
* start - a pointer to just after the end of the folder path string
*/
void _write_name(int id, char *start)
{
int i = _need_chars(id);
while (i > 0)
{
// Get current character
char c = '0';
if (id % 16 < 10)
c += id % 16;
else
c = 'a' + (id % 16) - 10;
// Put character
*(start + i - 1) = c;
// divide id, sub from i
id /= 16;
i -= 1;
}
}
/**
* Bind to the next available onboard socket in the given directory
* sock_dir - The directory containing osm sockets (or null for the default)
*/
int osm_bind_local(int sockfd, const char *sock_dir)
{
struct sockaddr_un name;
name.sun_family = AF_LOCAL;
strncpy(name.sun_path, sock_dir, sizeof(name.sun_path));
name.sun_path[sizeof(name.sun_path) - 1] = 0;
// Check for slash at end of path
int len = strlen(name.sun_path);
if (name.sun_path[len - 1] != '/')
{
name.sun_path[len] = '/';
len++;
}
// check that we won't overflow the buffer
if (len > sizeof(name.sun_path) - 2)
{
return -1;
}
// sequentially try to bind
int id = 0;
while(_need_chars(id) + len < sizeof(name.sun_path) - 1)
{
// write file name
_write_name(id, name.sun_path + len);
// try to bind
int size = offsetof(struct sockaddr_un, sun_path) + strlen(name.sun_path);
if (bind(sockfd, (struct sockaddr *) &name, size) > 0)
{
return 0;
}
// inc id
id++;
}
return -1;
}
/**
* Bind a new onboard socket
* sock_dir - The directory containing osm sockets (or null for the default)
* return - a negitve number on error, or the socket fd on success
*/
int osm_open_onboard(char *sock_dir)
{
int sockfd = socket(AF_LOCAL, SOCK_DGRAM, 0);
if (sockfd < 0)
{
perror("socket");
return sockfd;
}
int bound = -1;
if (sock_dir == NULL)
{
bound = osm_bind_local(sockfd, "/run/osm/onboard/");
}
else
{
bound = osm_bind_local(sockfd, sock_dir);
}
if (bound < 0)
{
perror("bind");
close(sockfd);
return bound;
}
return sockfd;
}
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