digitalmars.D - Linux prelink breaks DMD and GDC executables.
prelink (http://www.die.net/doc/linux/man/man8/prelink.8.html) screws up some D executables built by DMD or GDC v0.17, which is a potentially large problem because it is installed to run automatically by default on a lot of Linux systems (for most common system bin directories) from what I gather. I've seen odd problems apparently caused by prelink on C++ executables too (that's what prompted me to try it w/ D exe's), so the wisdom of having prelink run by default seems dubious at best. It's purely cause-and-effect for me because I haven't the time to dig into exactly what is happening to cause the problems. On Fedora systems a driver script is setup in /etc/cron.daily. I've been able to prevent the prelink by using the -L-pie switch (http://www.linuxfromscratch.org/hlfs/view/unstable/uclibc/chapter02/pie.html) However, I'm not real familiar with exactly what the consequences of -pie will be so I'm not recommending it, just putting this info. out there in the hopes that someone can explain the problem and work toward a fix. Obviously, this could have big consequences as more and more D executables make their way out into the wild in system bin directories. Anyone? Thanks, - Dave
Apr 07 2006
Dave wrote:prelink (http://www.die.net/doc/linux/man/man8/prelink.8.html) screws up some D executables built by DMD or GDC v0.17, which is a potentially large problem because it is installed to run automatically by default on a lot of Linux systems (for most common system bin directories) from what I gather. I've seen odd problems apparently caused by prelink on C++ executables too (that's what prompted me to try it w/ D exe's), so the wisdom of having prelink run by default seems dubious at best. It's purely cause-and-effect for me because I haven't the time to dig into exactly what is happening to cause the problems. On Fedora systems a driver script is setup in /etc/cron.daily. I've been able to prevent the prelink by using the -L-pie switch (http://www.linuxfromscratch.org/hlfs/view/unstable/uclibc/chapter02/pie.html) However, I'm not real familiar with exactly what the consequences of -pie will be so I'm not recommending it, just putting this info. out there in the hopes that someone can explain the problem and work toward a fix. Obviously, this could have big consequences as more and more D executables make their way out into the wild in system bin directories. Anyone?What actually happens to the executable ~ does it just die? Worse?
Apr 07 2006
Dave <Dave_member pathlink.com> kris wrote:Dave wrote:Some exe's segfault under some conditions, some don't. All I can say so far, but there is a direct cause-and-effect: compile and run it, and the exe works fine all day long, prelink the same executable and it crashes. Here's some code: import std.stdio, std.string, std.outbuffer; int main(char[][] args) { int n = args.length > 1 ? atoi(args[1]) : 1; OutBuffer ob = new OutBuffer(); for(int i = 0; i < n; i++) { ob.write("hello\n"); } writefln(ob.toString().length); return 0; } Note that running a prelinked strcat with 10_000 doesn't segfault, howerver it does when running it with 1_000_000. Compiling phobos with -g -release says it crashes in std/outbuffer.d:92. Run with just -g and it crashes at internal/invariant.d:16. I have a couple of other examples of prelinked D executables that also segfault, and those don't use OutBuffer so I don't think the problem can be isolated to that in conjunction with prelink. Something in the exe's is apparently getting hosed-up by prelink. - Daveprelink (http://www.die.net/doc/linux/man/man8/prelink.8.html) screws up some D executables built by DMD or GDC v0.17, which is a potentially large problem because it is installed to run automatically by default on a lot of Linux systems (for most common system bin directories) from what I gather. I've seen odd problems apparently caused by prelink on C++ executables too (that's what prompted me to try it w/ D exe's), so the wisdom of having prelink run by default seems dubious at best. It's purely cause-and-effect for me because I haven't the time to dig into exactly what is happening to cause the problems. On Fedora systems a driver script is setup in /etc/cron.daily. I've been able to prevent the prelink by using the -L-pie switch (http://www.linuxfromscratch.org/hlfs/view/unstable/uclibc/chapter02/pie.html) However, I'm not real familiar with exactly what the consequences of -pie will be so I'm not recommending it, just putting this info. out there in the hopes that someone can explain the problem and work toward a fix. Obviously, this could have big consequences as more and more D executables make their way out into the wild in system bin directories. Anyone?What actually happens to the executable ~ does it just die? Worse?
Apr 08 2006