RE: using spawn functions to avoid fork() errors -- FIXED
On 2/6/2014 8:50 AM, Steven Bardwell wrote: Larry - thanks for the link to the source for the spawn() APIs. It works perfectly on my 32-bit install (where, as it happens, the fork() issue never shows up either). However, on my 64-bit install, the spawnv() call is returning with an error -- 'No such file or directory' -- when I try to spawn /bin/sh. I have attached the output from 'strace' on this process. If you look at line 602, I think you can see where the exception gets generated. Can you see what is going on? I tried to create a simple test program that shows the problem, but (so far) they all work. Thanks. I am still trying to create a simple example, but the fact that it works on the 32-bit install inspired me to look again at the strace output, comparing the output from the install that works with the 64-bit strace output that shows the problem. /bin/sh is crashing, for sure, but it's not clear to me why that would be the case. It certainly has something to do with the way it's being invoked. But whether that's the problem (i.e. GIGO) or whether there's something wrong on the Cygwin side that your usage is conveniently bringing to light, I can't say. I'm assuming the former given your description so far. -- Larry I found the problem that was causing the failure of child creation logic on the 64-bit install but not on the 32-bit version: in an effort to make the output from 'ps' more useful, my application was over-writing the contents of argv[1] in the main process. This trick works fine in many flavors of Unix (including Interix and Linux and 32-bit Cygwin). However, in Cygwin 64-bit, it somehow corrupts things such that the child process created by fork() or spawnv() failed to load correctly. After removing that 'feature,' both spawnv() as well as the original fork() logic work without any problem. I really appreciate everyone's looking into this. Steve -- 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: using spawn functions to avoid fork() errors -- FIXED
On 2/6/2014 8:50 AM, Steven Bardwell wrote: Larry - thanks for the link to the source for the spawn() APIs. It works perfectly on my 32-bit install (where, as it happens, the fork() issue never shows up either). However, on my 64-bit install, the spawnv() call is returning with an error -- 'No such file or directory' -- when I try to spawn /bin/sh. I have attached the output from 'strace' on this process. If you look at line 602, I think you can see where the exception gets generated. Can you see what is going on? I tried to create a simple test program that shows the problem, but (so far) they all work. Thanks. I am still trying to create a simple example, but the fact that it works on the 32-bit install inspired me to look again at the strace output, comparing the output from the install that works with the 64-bit strace output that shows the problem. /bin/sh is crashing, for sure, but it's not clear to me why that would be the case. It certainly has something to do with the way it's being invoked. But whether that's the problem (i.e. GIGO) or whether there's something wrong on the Cygwin side that your usage is conveniently bringing to light, I can't say. I'm assuming the former given your description so far. -- Larry I found the problem that was causing the failure of child creation logic on the 64-bit install but not on the 32-bit version: in an effort to make the output from 'ps' more useful, my application was over-writing the contents of argv[1] in the main process. This trick works fine in many flavors of Unix (including Interix and Linux and 32-bit Cygwin). However, in Cygwin 64-bit, it somehow corrupts things such that the child process created by fork() or spawnv() failed to load correctly. After removing that 'feature,' both spawnv() as well as the original fork() logic work without any problem. I really appreciate everyone's looking into this. Steve -- 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: using spawn functions to avoid fork() errors -- FIXED
Greetings, Steven Bardwell! I found the problem that was causing the failure of child creation logic on the 64-bit install but not on the 32-bit version: in an effort to make the output from 'ps' more useful, my application was over-writing the contents of argv[1] in the main process. This trick works fine in many flavors of Unix (including Interix and Linux and 32-bit Cygwin). CYGWIN=wincmdln ? However, in Cygwin 64-bit, it somehow corrupts things such that the child process created by fork() or spawnv() failed to load correctly. After removing that 'feature,' both spawnv() as well as the original fork() logic work without any problem. Could still be NULL termination problem. If the strings you manipulating are in UTF16, you need TWO \0 to terminate the string. -- WBR, Andrey Repin (anrdae...@yandex.ru) 07.02.2014, 19:21 Sorry for my terrible english... -- 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
