Re: Pipes Again -- a simple test case
On Jan 8 17:30, Corinna Vinschen wrote: > On Jan 8 17:12, Houder wrote: > > On 2016-01-08 16:19, Corinna Vinschen wrote: > > >On Jan 4 10:24, Houder wrote: > > >>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 > > > > > >Thanks for the STC. However, given how this stuff works internally, > > >I have no good solution off the top of my head. I played with various > > >ideas but to no avail. I add this to my TODO list, but I probably > > >won't have a quick solution :( > > > > > > > > >Thanks, > > >Corinna > > > > > > > > >P.S: It would be really helpful if you could stick to the original > > > thread and simply use "reply-to" once a discussion has started. > > > It's very confusing having to connect the various threads. Thanks. > > > > Perhaps David B. can be helped by a Cygwin-specific patching to "cmp"? Eric? > > > > ... replacing the call to fstat() by a call to stat() ... > > (as shown in https://cygwin.com/ml/cygwin/2015-12/msg00348.html) > > > > By the way, thank you for reporting back to "us" about this. I already > > feared that a "general" solution would have to wait ... You have already > > too much on your plate. > > > > As a final point, I also tested FIFOs and (unix domain) sockets. > > > > FIFOs pass the test, sockets do not. > > Yes, that's expected. The underlying hack^Wmethod is the same for sockets > and pipes, while FIFOs have a real path on a real filesystem and thus have > a real inode number to fetch in stat/fstat. I applied a patch to make this work. Please give the latest developer snapshot from https://cygwin.com/snapshots/ a try. Thanks, Corinna -- Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Maintainer cygwin AT cygwin DOT com Red Hat signature.asc Description: PGP signature
Re: Pipes Again -- a simple test case
Corinna Vinschen cygwin.com> writes:
> Can you please provide the socket testcase?
Trying to send you what you ask for (using gmane.org, I have to copy/paste)
- t_stat3.c:
/*\
* 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
#define _BSD_SOURCE /* Get major() and minor() from */
#include
#include
#include
//#include "file_perms.h"
//#include "tlpi_hdr.h"
#include /* Standard I/O functions */
#include /* Prototypes of commonly used library functions,
plus EXIT_SUCCESS and EXIT_FAILURE constants */
#include /* Prototypes for many system calls */
#include /* Commonly used string-handling functions */
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, ...);
#include
#include
int
main()
{
char symlnk[64];
pid_t pid = getpid();
int sfd[2];
for (int f = 0; f < 2; f++) // step over the 1st and 2nd socket
{
if (!f) {
sfd[f] = socket(AF_UNIX, SOCK_STREAM, 0);
//sfd[f] = socket(AF_INET, SOCK_STREAM, 0);
if (sfd[f] == -1)
errExit("socket");
} else {
sfd[f] = socket(AF_UNIX, SOCK_STREAM, 0);
//sfd[f] = socket(AF_INET, SOCK_STREAM, 0);
if (sfd[f] == -1)
errExit("socket");
}
}
struct stat sb[2]; // one buffer for the 1st socket, one for the 2nd
int f;
char target[128];
ssize_t num;
printf("1st socket\n");
f = 0;
if (sprintf(symlnk, "/proc/%d/fd/%d", pid, sfd[f]) <= 0)
errExit("sprintf");
printf("... %s (symbolic link to the socket)\n", symlnk);
if ( (num = readlink( (const char *)symlnk, target, 128) ) == -1)
errExit("readlink");
if (num < 128) {
target[num] = '\0';
printf("... %s (target of symbolic link to the socket)\n", target);
printf("... using stat() on symbolic link: %s\n", symlnk);
//if (stat(target, sb + f) != 0) // not possible: target is NOT a
filename ...
if (stat(symlnk, sb + f) != 0)
errExit("stat");
displayStatInfo(sb + f);
printf("... using fstat()\n");
memset(sb + f, 0, sizeof(struct stat) ); // CLEAR
if (fstat(sfd[f], sb + f) != 0)
errExit("fstat");
displayStatInfo(sb + f);
}
#if 1
printf("\n2nd socket\n");
f = 1;
if (sprintf(symlnk, "/proc/%d/fd/%d", pid, sfd[f]) <= 0)
errExit("sprintf");
printf("... %s (symbolic link to the socket)\n", symlnk);
if ( (num = readlink( (const char *)symlnk, target, 128) ) == -1)
errExit("readlink");
if (num < 128) {
target[num] = '\0';
printf("... %s (target of symbolic link to the socket)\n", target);
printf("... using stat() on symbolic link: %s\n", symlnk);
//if (stat(target, sb + f) != 0) // not possible: target is NOT a
filename ...
if (stat(symlnk, sb + f) != 0)
errExit("stat");
displayStatInfo(sb + f);
printf("... using fstat()\n");
memset(sb + f, 0, sizeof(struct stat) ); // CLEAR
if (fstat(sfd[f], sb + f) != 0)
errExit("fstat");
Re: Pipes Again -- a simple test case
Corinna Vinschen cygwin.com> writes: > > > As a final point, I also tested FIFOs and (unix domain) sockets. > > > > > > FIFOs pass the test, sockets do not. > > > > Yes, that's expected. The underlying hack^Wmethod is the same for sockets > > and pipes, while FIFOs have a real path on a real filesystem and thus have > > a real inode number to fetch in stat/fstat. > > I applied a patch to make this work. Please give the latest developer > snapshot from https://cygwin.com/snapshots/ a try. Thank you! Down with flue on this side. Did a quick verification (32-bits Cygwin). Pipes look good. The problem with cmp apperas to be gone. Sockets still leave wanting, as shown here: @@ ./t_henri 1st socket ... /proc/4896/fd/3 (symbolic link to the socket) ... socket:[252] (target of symbolic link to the socket) ... using stat() on symbolic link: /proc/4896/fd/3 File type:socket Device containing i-node: (1e) major=30 minor=0 I-node number:38037da0d28c3faf - decimal: 4036207820734742447 File size:0 bytes ... using fstat() File type:socket Device containing i-node: (1e) major=30 minor=0 I-node number:1 - decimal: 1 File size:0 bytes 2nd socket ... /proc/4896/fd/4 (symbolic link to the socket) ... socket:[272] (target of symbolic link to the socket) ... using stat() on symbolic link: /proc/4896/fd/4 File type:socket Device containing i-node: (1e) major=30 minor=0 I-node number:38037da2d3885eb1 - decimal: 4036207829341200049 File size:0 bytes ... using fstat() File type:socket Device containing i-node: (1e) major=30 minor=0 I-node number:2 - decimal: 2 File size:0 bytes @@ Regards, Henri -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
Re: Pipes Again -- a simple test case
On Jan 11 16:13, Henri wrote: > Corinna Vinschen cygwin.com> writes: > > Can you please provide the socket testcase? > > Trying to send you what you ask for (using gmane.org, I have to copy/paste) Thanks! I applied a patch and created a new developer snapshot. I'll also upload a new cygwin test release later today. That's hopefully the last one. I intend to release end of this week. Thanks again, Corinna -- Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Maintainer cygwin AT cygwin DOT com Red Hat signature.asc Description: PGP signature
Re: Pipes Again -- a simple test case
On Jan 8 17:12, Houder wrote: > On 2016-01-08 16:19, Corinna Vinschen wrote: > >On Jan 4 10:24, Houder wrote: > >>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 > > > >Thanks for the STC. However, given how this stuff works internally, > >I have no good solution off the top of my head. I played with various > >ideas but to no avail. I add this to my TODO list, but I probably > >won't have a quick solution :( > > > > > >Thanks, > >Corinna > > > > > >P.S: It would be really helpful if you could stick to the original > > thread and simply use "reply-to" once a discussion has started. > > It's very confusing having to connect the various threads. Thanks. > > Perhaps David B. can be helped by a Cygwin-specific patching to "cmp"? Eric? > > ... replacing the call to fstat() by a call to stat() ... > (as shown in https://cygwin.com/ml/cygwin/2015-12/msg00348.html) > > By the way, thank you for reporting back to "us" about this. I already > feared that a "general" solution would have to wait ... You have already > too much on your plate. > > As a final point, I also tested FIFOs and (unix domain) sockets. > > FIFOs pass the test, sockets do not. Yes, that's expected. The underlying hack^Wmethod is the same for sockets and pipes, while FIFOs have a real path on a real filesystem and thus have a real inode number to fetch in stat/fstat. Corinna -- Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Maintainer cygwin AT cygwin DOT com Red Hat signature.asc Description: PGP signature
Re: Pipes Again -- a simple test case
On 2016-01-08 16:19, Corinna Vinschen wrote: On Jan 4 10:24, Houder wrote: 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 Thanks for the STC. However, given how this stuff works internally, I have no good solution off the top of my head. I played with various ideas but to no avail. I add this to my TODO list, but I probably won't have a quick solution :( Thanks, Corinna P.S: It would be really helpful if you could stick to the original thread and simply use "reply-to" once a discussion has started. It's very confusing having to connect the various threads. Thanks. Perhaps David B. can be helped by a Cygwin-specific patching to "cmp"? Eric? ... replacing the call to fstat() by a call to stat() ... (as shown in https://cygwin.com/ml/cygwin/2015-12/msg00348.html) By the way, thank you for reporting back to "us" about this. I already feared that a "general" solution would have to wait ... You have already too much on your plate. As a final point, I also tested FIFOs and (unix domain) sockets. FIFOs pass the test, sockets do not. Regards, Henri -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
Re: Pipes Again -- a simple test case
On Jan 4 10:24, Houder wrote: > 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 Thanks for the STC. However, given how this stuff works internally, I have no good solution off the top of my head. I played with various ideas but to no avail. I add this to my TODO list, but I probably won't have a quick solution :( Thanks, Corinna P.S: It would be really helpful if you could stick to the original thread and simply use "reply-to" once a discussion has started. It's very confusing having to connect the various threads. Thanks. -- Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Maintainer cygwin AT cygwin DOT com Red Hat signature.asc Description: PGP signature
Re: Pipes Again -- a simple test case
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. Regards Marco -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
Pipes Again -- a simple test case
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:
int
main()
{
struct stat sb[2];
int pfd[2];
pid_t pid = getpid();
if (pipe(pfd) != 0)
errExit("pipe");
for (int f = 0; f < 2; f++) // step over the read end and write end
of the pipe
{
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);
}
Linux shows:
@@ ./t_stat2
... /proc/968/fd/3 (symbolic link to the read end of the pipe)
... using stat()
File type:FIFO or pipe
Device containing i-node: (8) major=0 minor=8
I-node number:53bc - decimal: 21436
File size:0 bytes
... using stat()
File type:FIFO or pipe
Device containing i-node: (8) major=0 minor=8
I-node number:53bc - decimal: 21436
File size:0 bytes
... /proc/968/fd/4 (symbolic link to the write end of the pipe)
... using stat()
File type:FIFO or pipe
Device containing i-node: (8) major=0 minor=8
I-node number:53bc - decimal: 21436
File size:0 bytes
... using stat()
File type:FIFO or pipe
Device containing i-node: (8) major=0 minor=8
I-node number:53bc - decimal: 21436
File size:0 bytes
Cygwin shows:
@@ ./t_stat2
... /proc/2864/fd/3 (symbolic link to the read end of the pipe)
... using stat()
File type:FIFO or pipe
Device containing i-node: (c7) major=0 minor=199
I-node number:a325e1ba495b63cf - decimal:
11756050592531440591
File size:0 bytes
... using fstat()
File type:FIFO or pipe
Device containing i-node: (c6) major=0 minor=198
I-node number:0 - decimal: 0 < zero, the
non-existing i-node ...
File size:0 bytes
... /proc/2864/fd/4 (symbolic link to the write end of the pipe)
... using stat()
File type:FIFO or pipe
Device containing i-node: (c7) major=0 minor=199
I-node number:a325e1ba495f64cb - decimal:
11756050592531702987 < Linux shows the same i-node
File size:0 bytes
... using fstat()
File type:FIFO or pipe
Device containing i-node: (c5) major=0 minor=197
I-node number:0 - decimal: 0 < ditto
File size:0 bytes
=
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Re: Pipes Again -- a simple test case
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 */
#include
#include
#include
//#include "file_perms.h"
//#include "tlpi_hdr.h"
#include /* Standard I/O functions */
#include /* Prototypes of commonly used library functions,
plus EXIT_SUCCESS and EXIT_FAILURE constants */
#include /* Prototypes for many system calls */
#include /* Declares errno and defines error constants */
#include /* Commonly used string-handling functions */
#include
#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:
