Messages in this thread | | | From | (David Wagner) | Subject | Re: light weight user level semaphores | Date | 24 Apr 2001 00:19:46 GMT |
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Linus Torvalds wrote: >Ehh.. I will bet you $10 USD that if libc allocates the next file >descriptor on the first "malloc()" in user space (in order to use the >semaphores for mm protection), programs _will_ break. > >You want to take the bet?
Good point. Speaking of which: ioctl(fd, UIOCATTACHSEMA, ...); seems to act like dup(fd) if fd was opened on "/dev/usemaclone" (see drivers/sgi/char/usema.c). According to usema(7), this is intended to help libraries implement semaphores.
Is this a bad coding? Should the kernel really support an ioctl() that can silently allocate the next file descriptor? This seems like asking for trouble. Or, maybe I just misunderstood something. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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