APUE[ "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 */
#include <errno.h>        /* for definition of errno */
#include <stdarg.h>       /* ISO C variable aruments */
static void err_doit(int, int, const char *, va_list);
/*
err_ret非致命错误输出
与err_sys相比，没有exit()，并不退出函数。
相同的是都调用stderror(errno)打印详细出错信息。
可变参数列表中多为vsnprintf等打印参数的参数列表。
*/
void
err_ret(const char *fmt, ...)
{
va_list     ap;

va_start(ap, fmt);
err_doit(1, errno, fmt, ap);
va_end(ap);
}

/*
* Fatal error related to a system call.
* Print a message and terminate.
*/
void
err_sys(const char *fmt, ...)
{
va_list     ap;

va_start(ap, fmt);
err_doit(1, errno, fmt, ap);
va_end(ap);
exit(1);                /* 退出 */
}

/*
* Fatal error unrelated to a system call.
* Error code passed as explict parameter.
* Print a message and terminate.
* 不调用系统打印出错信息。
*/
void
err_exit(int error, const char *fmt, ...)
{
va_list     ap;

va_start(ap, fmt);
err_doit(1, error, fmt, ap);
va_end(ap);
exit(1);
}

/*
* 不调用系统出错信息，但退出程序
* Fatal error related to a system call.
* Print a message, dump core, and terminate.
*/
void
err_dump(const char *fmt, ...)
{
va_list     ap;

va_start(ap, fmt);
err_doit(1, errno, fmt, ap);
va_end(ap);
abort();        /* dump core and terminate */
exit(1);        /* shouldn't get here */
}

/*
* Nonfatal error unrelated to a system call.
* Print a message and return.
*/
void
err_msg(const char *fmt, ...)
{
va_list     ap;

va_start(ap, fmt);
err_doit(0, 0, fmt, ap);
va_end(ap);
}

/*
* 不调用系统出错信息，但退出程序
* Print a message and terminate.
*/
void
err_quit(const char *fmt, ...)
{
va_list     ap;

va_start(ap, fmt);
err_doit(0, 0, fmt, ap);
va_end(ap);
exit(1);
}

/*
* Print a message and return to caller.
* Caller specifies "errnoflag".
*/
static void
err_doit(int errnoflag, int error, const char *fmt, va_list ap)
{
char    buf[MAXLINE];

vsnprintf(buf, MAXLINE, fmt, ap);       /* vsnprintf与snprintf区别在于vsnprintf调用可变参数列表 */
if (errnoflag)
/* 在buf后追加系统出错信息 */
snprintf(buf+strlen(buf), MAXLINE-strlen(buf), ": %s",
strerror(error));
strcat(buf, "\n");
fflush(stdout);     /* in case stdout and stderr are the same */
fputs(buf, stderr);
fflush(NULL);       /* flushes all stdio output streams */
}