/*
* Concatenates NULL-terminated list of arguments into a single
* commmand and executes it
* @param argv argument list
* @return stdout of executed command or NULL if an error occurred
*/
char *_backtick(char *const argv[])
{
int filedes[2];
pid_t pid;
int status;
char *buf = NULL;
/*
* create pipe
*/
if (pipe(filedes) == -1) {
perror(argv[0]);
return NULL;
}
switch (pid = fork()) {
case -1: /* error */
return NULL;
case 0: /* child */
close(filedes[0]); /* close read end of pipe */
dup2(filedes[1], 1); /* redirect stdout to write end of
* pipe */
close(filedes[1]); /* close write end of pipe */
execvp(argv[0], argv);
exit(errno);
break;
default: /* parent */
close(filedes[1]); /* close write end of pipe */
buf = fd2str(filedes[0]);
waitpid(pid, &status, 0);
break;
}
return buf;
}
/*
* Reads file and returns contents
* @param path path to file
* @return contents of file or NULL if an error occurred
*/
char *file2str(const char *path)
{
int fd;
if ((fd = open(path, O_RDONLY)) == -1) {
perror(path);
return NULL;
}
return fd2str(fd);
}