/**************************************************************************                  Copyright (C) Michael Kerrisk, 2014.                   **                                                                         ** This program is free software. You may use, modify, and redistribute it ** under the terms of the GNU Lesser General Public License as published   ** by the Free Software Foundation, either version 3 or (at your option)   ** any later version. This program is distributed without any warranty.    ** See the files COPYING.lgpl-v3 and COPYING.gpl-v3 for details.           *\*************************************************************************//* error_functions.c   Some standard error handling routines used by various programs.*/#include <stdarg.h>#include "error_functions.h"#include "tlpi_hdr.h"#include "ename.c.inc"          /* Defines ename and MAX_ENAME */#ifdef __GNUC__                 /* Prevent ‘gcc -Wall‘ complaining  */__attribute__ ((__noreturn__))  /* if we call this function as last */#endif                          /* statement in a non-void function */static voidterminate(Boolean useExit3){    char *s;    /* Dump core if EF_DUMPCORE environment variable is defined and       is a nonempty string; otherwise call exit(3) or _exit(2),       depending on the value of ‘useExit3‘. */    s = getenv("EF_DUMPCORE");    if (s != NULL && *s != ‘\0‘)        abort();    else if (useExit3)        exit(EXIT_FAILURE);    else        _exit(EXIT_FAILURE);}/* Diagnose ‘errno‘ error by:      * outputting a string containing the error name (if available        in ‘ename‘ array) corresponding to the value in ‘err‘, along        with the corresponding error message from strerror(), and      * outputting the caller-supplied error message specified in        ‘format‘ and ‘ap‘. */static voidoutputError(Boolean useErr, int err, Boolean flushStdout,        const char *format, va_list ap){#define BUF_SIZE 500    char buf[BUF_SIZE], userMsg[BUF_SIZE], errText[BUF_SIZE];    vsnprintf(userMsg, BUF_SIZE, format, ap);    if (useErr)        snprintf(errText, BUF_SIZE, " [%s %s]",                (err > 0 && err <= MAX_ENAME) ?                ename[err] : "?UNKNOWN?", strerror(err));    else        snprintf(errText, BUF_SIZE, ":");    snprintf(buf, BUF_SIZE, "ERROR%s %s\n", errText, userMsg);    if (flushStdout)        fflush(stdout);       /* Flush any pending stdout */    fputs(buf, stderr);    fflush(stderr);           /* In case stderr is not line-buffered */}/* Display error message including ‘errno‘ diagnostic, and   return to caller */voiderrMsg(const char *format, ...){    va_list argList;    int savedErrno;    savedErrno = errno;       /* In case we change it here */    va_start(argList, format);    outputError(TRUE, errno, TRUE, format, argList);    va_end(argList);    errno = savedErrno;}/* Display error message including ‘errno‘ diagnostic, and   terminate the process */voiderrExit(const char *format, ...){    va_list argList;    va_start(argList, format);    outputError(TRUE, errno, TRUE, format, argList);    va_end(argList);    terminate(TRUE);}/* Display error message including ‘errno‘ diagnostic, and   terminate the process by calling _exit().   The relationship between this function and errExit() is analogous   to that between _exit(2) and exit(3): unlike errExit(), this   function does not flush stdout and calls _exit(2) to terminate the   process (rather than exit(3), which would cause exit handlers to be   invoked).   These differences make this function especially useful in a library   function that creates a child process that must then terminate   because of an error: the child must terminate without flushing   stdio buffers that were partially filled by the caller and without   invoking exit handlers that were established by the caller. */voiderr_exit(const char *format, ...){    va_list argList;    va_start(argList, format);    outputError(TRUE, errno, FALSE, format, argList);    va_end(argList);    terminate(FALSE);}/* The following function does the same as errExit(), but expects   the error number in ‘errnum‘ */voiderrExitEN(int errnum, const char *format, ...){    va_list argList;    va_start(argList, format);    outputError(TRUE, errnum, TRUE, format, argList);    va_end(argList);    terminate(TRUE);}/* Print an error message (without an ‘errno‘ diagnostic) */voidfatal(const char *format, ...){    va_list argList;    va_start(argList, format);    outputError(FALSE, 0, TRUE, format, argList);    va_end(argList);    terminate(TRUE);}/* Print a command usage error message and terminate the process */voidusageErr(const char *format, ...){    va_list argList;    fflush(stdout);           /* Flush any pending stdout */    fprintf(stderr, "Usage: ");    va_start(argList, format);    vfprintf(stderr, format, argList);    va_end(argList);    fflush(stderr);           /* In case stderr is not line-buffered */    exit(EXIT_FAILURE);}/* Diagnose an error in command-line arguments and   terminate the process */voidcmdLineErr(const char *format, ...){    va_list argList;    fflush(stdout);           /* Flush any pending stdout */    fprintf(stderr, "Command-line usage error: ");    va_start(argList, format);    vfprintf(stderr, format, argList);    va_end(argList);    fflush(stderr);           /* In case stderr is not line-buffered */    exit(EXIT_FAILURE);}

/**************************************************************************                  Copyright (C) Michael Kerrisk, 2014.                   **                                                                         ** This program is free software. You may use, modify, and redistribute it ** under the terms of the GNU Lesser General Public License as published   ** by the Free Software Foundation, either version 3 or (at your option)   ** any later version. This program is distributed without any warranty.    ** See the files COPYING.lgpl-v3 and COPYING.gpl-v3 for details.           *\*************************************************************************//* error_functions.h   Header file for error_functions.c.*/#ifndef ERROR_FUNCTIONS_H#define ERROR_FUNCTIONS_H/* Error diagnostic routines */void errMsg(const char *format, ...);#ifdef __GNUC__    /* This macro stops ‘gcc -Wall‘ complaining that "control reaches       end of non-void function" if we use the following functions to       terminate main() or some other non-void function. */#define NORETURN __attribute__ ((__noreturn__))#else#define NORETURN#endifvoid errExit(const char *format, ...) NORETURN ;void err_exit(const char *format, ...) NORETURN ;void errExitEN(int errnum, const char *format, ...) NORETURN ;void fatal(const char *format, ...) NORETURN ;void usageErr(const char *format, ...) NORETURN ;void cmdLineErr(const char *format, ...) NORETURN ;#endif