On 2016-01-04 09:52, Marco Atzeri wrote:
On 04/01/2016 09:03, Houder wrote:
Hi Corinna,
I have been looking for an STC to show why cmp fails on Cygwin (and to
show the
difference between Cygwin and Linux).
The STC below creates a pipe (pipe() is used), followed by calls to
fstat() and
stat() for both the read end and the write end of the pipe.
(I also tested with popen()/pclose(): same result)
Regards,
Henri
Btw, I am using W7 prof.; Cygwin-32 and Cygwin-64; 2.3.1 and 2.4.0
=====
The code for the STC is basically as follows:
in general a STC should be complete and attached as file.
I know where you took errExit and displayStatInfo, but
it is anyway a extra effort time consuming for the others.
Yup ... find it attached to this post ... (I hope).
(I was busy "compiling" everyting in one file :-)
Regards,
Henri
/*************************************************************************\
* Copyright (C) Michael Kerrisk, 2014. *
* *
* This program is free software. You may use, modify, and redistribute it *
* under the terms of the GNU Affero 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 file COPYING.agpl-v3 for details. *
\*************************************************************************/
/* Listing 15-1 */
/* t_stat.c -- heavily modified
- using fstat: minor: 198/7 ... i-node: both (mostly) zero <==== my guess is that Cygwin is "in error"
- using stat: minor: 199 ... i-node: numbers are different from one another (and non-zero)
*/
#define _BSD_SOURCE /* Get major() and minor() from <sys/types.h> */
#include <sys/types.h>
#include <sys/stat.h>
#include <time.h>
//#include "file_perms.h"
//#include "tlpi_hdr.h"
#include <stdio.h> /* Standard I/O functions */
#include <stdlib.h> /* Prototypes of commonly used library functions,
plus EXIT_SUCCESS and EXIT_FAILURE constants */
#include <unistd.h> /* Prototypes for many system calls */
#include <errno.h> /* Declares errno and defines error constants */
#include <string.h> /* Commonly used string-handling functions */
#include <stdarg.h>
#ifdef TRUE
#undef TRUE
#endif
#ifdef FALSE
#undef FALSE
#endif
typedef enum { FALSE, TRUE } Boolean;
static char *ename[] = {
/* 0 */ "",
/* 1 */ "EPERM", "ENOENT", "ESRCH", "EINTR", "EIO", "ENXIO",
/* 7 */ "E2BIG", "ENOEXEC", "EBADF", "ECHILD",
/* 11 */ "EAGAIN/EWOULDBLOCK", "ENOMEM", "EACCES", "EFAULT",
/* 15 */ "ENOTBLK", "EBUSY", "EEXIST", "EXDEV", "ENODEV",
/* 20 */ "ENOTDIR", "EISDIR", "EINVAL", "ENFILE", "EMFILE",
/* 25 */ "ENOTTY", "ETXTBSY", "EFBIG", "ENOSPC", "ESPIPE",
/* 30 */ "EROFS", "EMLINK", "EPIPE", "EDOM", "ERANGE", "ENOMSG",
/* 36 */ "EIDRM", "ECHRNG", "EL2NSYNC", "EL3HLT", "EL3RST",
/* 41 */ "ELNRNG", "EUNATCH", "ENOCSI", "EL2HLT", "EDEADLK",
/* 46 */ "ENOLCK", "", "", "", "EBADE", "EBADR", "EXFULL",
/* 53 */ "ENOANO", "EBADRQC", "EBADSLT", "EDEADLOCK", "EBFONT",
/* 58 */ "", "", "ENOSTR", "ENODATA", "ETIME", "ENOSR", "ENONET",
/* 65 */ "ENOPKG", "EREMOTE", "ENOLINK", "EADV", "ESRMNT",
/* 70 */ "ECOMM", "EPROTO", "", "", "EMULTIHOP", "ELBIN",
/* 76 */ "EDOTDOT", "EBADMSG", "", "EFTYPE", "ENOTUNIQ", "EBADFD",
/* 82 */ "EREMCHG", "ELIBACC", "ELIBBAD", "ELIBSCN", "ELIBMAX",
/* 87 */ "ELIBEXEC", "ENOSYS", "ENMFILE", "ENOTEMPTY",
/* 91 */ "ENAMETOOLONG", "ELOOP", "", "", "EOPNOTSUPP",
/* 96 */ "EPFNOSUPPORT", "", "", "", "", "", "", "", "ECONNRESET",
/* 105 */ "ENOBUFS", "EAFNOSUPPORT", "EPROTOTYPE", "ENOTSOCK",
/* 109 */ "ENOPROTOOPT", "ESHUTDOWN", "ECONNREFUSED", "EADDRINUSE",
/* 113 */ "ECONNABORTED", "ENETUNREACH", "ENETDOWN", "ETIMEDOUT",
/* 117 */ "EHOSTDOWN", "EHOSTUNREACH", "EINPROGRESS", "EALREADY",
/* 121 */ "EDESTADDRREQ", "EMSGSIZE", "EPROTONOSUPPORT",
/* 124 */ "ESOCKTNOSUPPORT", "EADDRNOTAVAIL", "ENETRESET",
/* 127 */ "EISCONN", "ENOTCONN", "ETOOMANYREFS", "EPROCLIM",
/* 131 */ "EUSERS", "EDQUOT", "ESTALE", "ENOTSUP", "ENOMEDIUM",
/* 136 */ "ENOSHARE", "ECASECLASH", "EILSEQ", "EOVERFLOW",
/* 140 */ "ECANCELED", "ENOTRECOVERABLE", "EOWNERDEAD", "ESTRPIPE"
};
#define MAX_ENAME 143
static void
displayStatInfo(const struct stat *sb)
{
printf("File type: ");
switch (sb->st_mode & S_IFMT) {
case S_IFREG: printf("regular file\n"); break;
case S_IFDIR: printf("directory\n"); break;
case S_IFCHR: printf("character device\n"); break;
case S_IFBLK: printf("block device\n"); break;
case S_IFLNK: printf("symbolic (soft) link\n"); break;
case S_IFIFO: printf("FIFO or pipe\n"); break;
case S_IFSOCK: printf("socket\n"); break;
default: printf("unknown file type?\n"); break;
}
printf("Device containing i-node: (%lx) major=%lu minor=%lu\n",
(long) sb->st_dev, (long) major(sb->st_dev), (long) minor(sb->st_dev));
printf("I-node number: %llx - decimal: %llu\n", sb->st_ino, sb->st_ino);
if (S_ISCHR(sb->st_mode) || S_ISBLK(sb->st_mode))
printf(" **** Device number (st_rdev): major=%ld; minor=%ld\n",
(long) major(sb->st_rdev), (long) minor(sb->st_rdev));
printf("File size: %lld bytes\n", (long long) sb->st_size);
}
void errExit(const char *format, ...);
int
main(int argc, char *argv[])
{
struct stat sb[2];
int pfd[2];
pid_t pid = getpid();
if (pipe(pfd) != 0)
errExit("pipe");
for (int f = 0; f < 2; f++)
{
char symlnk[64];
if (sprintf(symlnk, "/proc/%d/fd/%d", pid, pfd[0 + f]) <= 0)
errExit("sprintf");
!f ? printf("... %s (symbolic link to the read end of the pipe)\n", symlnk)
: printf("... %s (symbolic link to the write end of the pipe)\n", symlnk);
printf("... using stat()\n");
if (stat(symlnk, sb) != 0)
errExit("stat");
displayStatInfo(sb);
printf("... using fstat()\n");
if ( fstat(pfd[0 + f], sb + 1) != 0 )
errExit("fstat");
displayStatInfo(sb + 1);
}
exit(EXIT_SUCCESS);
}
static void
terminate(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);
}
static void
outputError(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 */
}
void
errExit(const char *format, ...)
{
va_list argList;
va_start(argList, format);
outputError(TRUE, errno, TRUE, format, argList);
va_end(argList);
terminate(TRUE);
}
//=====
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