UNIX ENVIRONMENT C PROGRAMMING Take the following sample program.Add the followi
ID: 664632 • Letter: U
Question
UNIX ENVIRONMENT C PROGRAMMING
Take the following sample program.Add the following printout to stdout:
a) OS brand and version,
b) FILE_NAME_MAX supported on the system,
c) OPEN_MAX supported on the system,
d) Parent PID,
e) Child PID for every command typed in(date,pwd,ls,whoami,uname).
Submit the source code and snapshot of all screen printouts.
APUE.C
#include "apue.h"
#include <sys/wait.h>
int main(void)
{
char buf[MAXLINE]; /*from apue.h*/
pid_t pid;
int status;
printf("%%"); /*print prompt (printf requires %% to print %) */
while (fgets(buf, MAXLINE, stdin) != NULL){
if (buf[strlen(buf) - 1] == ' ')
buf[strlen(buf) - 1] = 0;/*replace new line with null*/
if ((pid = fork()) < 0){
err_sys("fork error");
}
else if (pid == 0){ /*child*/
execlp(buf, buf, (char *)0);
err_ret("couldn't execute:%s", buf);
exit(127);
}
/*parent*/
if ((pid = waitpid(pid, &status, 0)) < 0)
err_sys("waitpid error");
printf("%%");
}
exit(0);
APUE.H
/*
* Our own header, to be included before all standard system headers.
*/
#ifndef _APUE_H
#define _APUE_H
#define _POSIX_C_SOURCE 200809L
#if defined(SOLARIS) /* Solaris 10 */
#define _XOPEN_SOURCE 600
#else
#define _XOPEN_SOURCE 700
#endif
#include <sys/types.h> /* some systems still require this */
#include <sys/stat.h>
#include <sys/termios.h> /* for winsize */
#if defined(MACOS) || !defined(TIOCGWINSZ)
#include <sys/ioctl.h>
#endif
#include <stdio.h> /* for convenience */
#include <stdlib.h> /* for convenience */
#include <stddef.h> /* for offsetof */
#include <string.h> /* for convenience */
#include <unistd.h> /* for convenience */
#include <signal.h> /* for SIG_ERR */
#define MAXLINE 4096 /* max line length */
/*
* Default file access permissions for new files.
*/
#define FILE_MODE (S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH)
/*
* Default permissions for new directories.
*/
#define DIR_MODE (FILE_MODE | S_IXUSR | S_IXGRP | S_IXOTH)
typedef void Sigfunc(int); /* for signal handlers */
#define min(a,b) ((a) < (b) ? (a) : (b))
#define max(a,b) ((a) > (b) ? (a) : (b))
/*
* Prototypes for our own functions.
*/
char *path_alloc(size_t *); /* {Prog pathalloc} */
long open_max(void); /* {Prog openmax} */
int set_cloexec(int); /* {Prog setfd} */
void clr_fl(int, int);
void set_fl(int, int); /* {Prog setfl} */
void pr_exit(int); /* {Prog prexit} */
void pr_mask(const char *); /* {Prog prmask} */
Sigfunc *signal_intr(int, Sigfunc *); /* {Prog signal_intr_function} */
void daemonize(const char *); /* {Prog daemoninit} */
void sleep_us(unsigned int); /* {Ex sleepus} */
ssize_t readn(int, void *, size_t); /* {Prog readn_writen} */
ssize_t writen(int, const void *, size_t); /* {Prog readn_writen} */
int fd_pipe(int *); /* {Prog sock_fdpipe} */
int recv_fd(int, ssize_t(*func)(int,
const void *, size_t)); /* {Prog recvfd_sockets} */
int send_fd(int, int); /* {Prog sendfd_sockets} */
int send_err(int, int,
const char *); /* {Prog senderr} */
int serv_listen(const char *); /* {Prog servlisten_sockets} */
int serv_accept(int, uid_t *); /* {Prog servaccept_sockets} */
int cli_conn(const char *); /* {Prog cliconn_sockets} */
int buf_args(char *, int(*func)(int,
char **)); /* {Prog bufargs} */
int tty_cbreak(int); /* {Prog raw} */
int tty_raw(int); /* {Prog raw} */
int tty_reset(int); /* {Prog raw} */
void tty_atexit(void); /* {Prog raw} */
struct termios *tty_termios(void); /* {Prog raw} */
int ptym_open(char *, int); /* {Prog ptyopen} */
int ptys_open(char *); /* {Prog ptyopen} */
#ifdef TIOCGWINSZ
pid_t pty_fork(int *, char *, int, const struct termios *,
const struct winsize *); /* {Prog ptyfork} */
#endif
int lock_reg(int, int, int, off_t, int, off_t); /* {Prog lockreg} */
#define read_lock(fd, offset, whence, len)
lock_reg((fd), F_SETLK, F_RDLCK, (offset), (whence), (len))
#define readw_lock(fd, offset, whence, len)
lock_reg((fd), F_SETLKW, F_RDLCK, (offset), (whence), (len))
#define write_lock(fd, offset, whence, len)
lock_reg((fd), F_SETLK, F_WRLCK, (offset), (whence), (len))
#define writew_lock(fd, offset, whence, len)
lock_reg((fd), F_SETLKW, F_WRLCK, (offset), (whence), (len))
#define un_lock(fd, offset, whence, len)
lock_reg((fd), F_SETLK, F_UNLCK, (offset), (whence), (len))
pid_t lock_test(int, int, off_t, int, off_t); /* {Prog locktest} */
#define is_read_lockable(fd, offset, whence, len)
(lock_test((fd), F_RDLCK, (offset), (whence), (len)) == 0)
#define is_write_lockable(fd, offset, whence, len)
(lock_test((fd), F_WRLCK, (offset), (whence), (len)) == 0)
void err_msg(const char *, ...); /* {App misc_source} */
void err_dump(const char *, ...) __attribute__((noreturn));
void err_quit(const char *, ...) __attribute__((noreturn));
void err_cont(int, const char *, ...);
void err_exit(int, const char *, ...) __attribute__((noreturn));
void err_ret(const char *, ...);
void err_sys(const char *, ...) __attribute__((noreturn));
void log_msg(const char *, ...); /* {App misc_source} */
void log_open(const char *, int, int);
void log_quit(const char *, ...) __attribute__((noreturn));
void log_ret(const char *, ...);
void log_sys(const char *, ...) __attribute__((noreturn));
void log_exit(int, const char *, ...) __attribute__((noreturn));
void TELL_WAIT(void); /* parent/child from {Sec race_conditions} */
void TELL_PARENT(pid_t);
void TELL_CHILD(pid_t);
void WAIT_PARENT(void);
void WAIT_CHILD(void);
#endif /* _APUE_H */
Explanation / Answer
#include "apue.h"
#include <sys/wait.h>
#define _POSIX_FILE_NAME_MAX
#include<iostream.h>
#include<unistd.h>
int main()
{
#ifdef_POSIX_FILE_NAME
cout<< "System conforms to POSIX: " << _POSIX_FILE_NAME << end1;
#else
cout << "_POSIX_FILE_NAME is undefined " ;
#endif
return 0;
}
#define _POSIX_OPEN_MAX
#define_POSIX_C_OPEN_MAX
#include <iostream.h>
#include <unistd.h>
int main()
{
#ifdef _POSIX_OPEN_MAX
cout << "System conforms to POSIX: " << _POSIX_OPEN_MAX << end1;
#else
cout << "_POSIX_OPEN_MAX is undefined ";
#endif
return 0;
}
#include "version.h"
const char * build_date = "2009-11-10 11:09";
#ifndef VERSION_H
#define VERSION_H
extern const char * build_date; /* 2009-11-10 11:09 */
extern const char * build_git_sha; /* 6b54ea36e92d4907aba8b3fade7f2d58a921b6cd */
static void sig_int(int); /*signal catching function*/
int main(void)
{
char buf[MAXLINE]; /*from apue.h* /
pid_t pid;
int status;
if (signal(SIGINT, sig_int) == SIG_ERR)
err_sys("signal error");
printf("%%"); /*print prompt (printf requires %% to print %) */
while (fgets(buf, MAXLINE, stdin) ! = NULL) {
if (buf[strlen(buf) - 1] == ' ' )
buf[strlen(buf) - 1] = 0; /*replace new line with null*/
if ((pid = fork()) < 0) {
err-sys("fork error");
}
else if (pid == 0) { /*child*/
execlp(buf, buf, (char *) 0);
err_ret("couldn't execute:%s", buf);
exit(127);
}
int main()
{
pid_t pid;
if ((pid-fork()) < 0)
{
cout << "FORK ERROR " <<end1;
}
else
if (pid--0)
{
charatatime("output from child ");
}
else
{
charatatime("output from parent ");
}
exit(0);
}
void charatatime(char *str)
{
char *ptr;
int c;
setbuf(stdout,NULL);
for(ptr-str; (c-*ptr++) !-0;)
putc(c,stdout);
}
/*parent*/
if ((pid = waitpid(pid, &status, 0)) < 0)
err_sys("waitpid error");
printf("%%");
}
exit(0);
}
void sig_int(int signo) {
printf("interrupt %% ");
}
APUE.H
/*
*Our own header, to be included before all standard headers.
*/
#ifndef _APUE_H
#define _APUE_H
#define _POSIX_C_SOURCE 200809L
#if defined(SOLARIS) /* Solaris 10 */
#define_XOPEN_SOURCE 600
#else
#define _XOPEN_SOURCE 700
#endif
#include <sys/types.h> /* some systems still require this */
#include <sys/stat.h>
#include <sys/termios.h> /* for winsize */
#if defined(MACOS) | | !defined(TIOCGWINSZ)
#include <sys/ioctl.h>
#endif
#include <stdio.h> /* for convenience */
#include <stdlib.h> /* for convenience*/
#include <stddef.h> /* for offsetof */
#include <string.h> /*for convenience */
#include <unistd.h> /* for convenience */
#include <signal.h> /* for SIG_ERR */
#define MAXLINE 4096 /*max line length*/
/*
* Default file access permissions for new files
*/
#define FILE_MODE (S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH)
/*
*Default permissions for new directories
*/
#define DIR_MODE (FILE_MODE | S_IXUSR | S_IXGRP | S_IXOTH)
typedef void Sigfunc(int); /* for signal handlers */
#define min(a,b) ((a) < (b) ? (a) : (b))
#define max(a,b) ((a) > (b) ? (a) : (b))
/*
* prototypes for our own functions.
*/
char *path_alloc(size_t *); /* {prog pathalloc} */
long open_max(void); /* {prog openmax} */
int set_cloexec(int); /* {prog setfd} */
void clr_fl(int, int);
void set_fl(int, int); /* {prog setfl} */
void pr_exit(int); /*{prog prexit} */
void pr_mask(const char *); /* {prog prmask} */
sigfunc *signal_intr(int, sigfunc *); /* {prog signal_intr_function} */
void daemonize(const char *); /* {prog daemoninit} */
void sleep_us(unsigned int); /* {Ex sleepus} */
ssize_t readn(int, void *, size_t); /* {prog readn_writen} */
ssize_t writen(int, const void *, size_t); /* {prog readn_writen} */
int fd_pipe(int *); /* {prog sock_fdpipe} */
int recv_fd(int, ssize_t (*func) (int, const void *, size_t)); /* {prog sendfd_sockets} */
int serv_listen(const char *); /* {prog servlisten_sockets} */
int serv_accept(int, uid_t *); /* {prog servaccept_sockets} */
int cli_conn(const char *); /* {prog cliconn_sockets} */
int buf_args(char *, int (*func) (int, char **)); /* {prog bufargs} */
int tty_cbreak(int); /* {prog raw} */
int tty_raw(int); /* {prog raw} */
int tty_reset(int); /* {prog raw} */
void tty_atexit(void); /* {prog raw} */
struct termios *tty_termios(void); /*{prog raw}*/
int pytm_open(char *, int); /*{prog ptyopen}*/
int ptys_open(char *, int); /*{prog ptyopen}*/
#ifdef TIOCGWINSZ
pid_t pty_fork(int *,char *, int, const struct termios *, const struct winsize *); /* {prog ptyfork} */
#endif
int lock _reg(int, int, int, off_t, int, off_t); /* { prog lockreg} */
#define read_lock(fd, offset, whence, len)
lock-reg ( (fd), F_SETLK, F_RDLCK, (offset), (whence), (len))
#define readw_lock(fd, offset, whence, len)
lock-reg((fd), F-SETLKW, F_RDLCK, (offset), (whence), (len))
#define write_lock(fd, offset, whence, len)
lock_reg((fd), F_SETLK, F-WRLCK, (offset), (whence), (len))
#define writew_lock(fd, offset, whence, len)
lock_reg((fd), F_SETLKW, F_WRLCK, (offset), (whence), (len))
#define un_lock(fd, offset, whence, len)
lock_reg((fd), F_SETLK, F_UNLCK, (offset), (whence), (len))
pid_t lock_test(int, int, off_t, int, off_t); /* {prog locktest} */
#define is_read_lockable(fd, offset, whence, len)
(lock_test((fd), F_RDLCK, (offset), (whence), (len)) == 0)
#define is_write_lockable(fd, offset, whence, len)
(lock_test((fd), F_WRLCK, (offset), (whence), (len)) == 0)
void err_msg(const char *,......); /* {App misc_source} */
void err-dump(const char *,.....) _attribute_((nonreturn));
void err-quit(const char *,......) _attribute_((nonreturn));
void err_cont(int, const char *,....);
void err_exit(int, const char * ,.....) _attribute_((nonreturn));
void err_ret(const char *,.....);
void err_sys(const char *, ....) _attribute_((nonreturn));
void log_msg(const char *, .....); /* {App misc_source} */
void log_open(const char *, int, int);
void log-quit(const char *, .....) _attribute_((nonreturn));
void log_ret(const char *, .....);
void log_sys(const char *, ....) _attribute_((nonreturn));
void log_exit(int, const char *, ....) _attribute_((nonreturn));
void TELL_WAIT(void); /* parent/child from {Sec race_conditions} */
void TELL_PARENT(pid-t);
void TELL_CHILD(pid_t);
void WAIT_PARENT(void);
void WAIT_CHILD(void);
#endif /* _APUE_H */
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