Rich Felker <dalias@xxxxxxxxxx> writes: > On Fri, Jan 09, 2015 at 08:56:26PM +0000, Al Viro wrote: >> On Fri, Jan 09, 2015 at 03:48:15PM -0500, Rich Felker wrote: >> > I think this is a case that needs to be fixed, though it's hard. The >> > normal correct usage for fexecve is to always pass an O_CLOEXEC file >> > descriptor, and the caller can't really be expected to know whether >> > the file is a script or not. We discussed workarounds before and one >> > idea I proposed was having fexecve provide a "one open only" magic >> > symlink in /proc/self/ to pass to the interpreter. It would behave >> > like an O_PATH file descriptor magic symlink in /proc/self/fd, but >> > would automatically cease to exist on the first open (at which point >> > the interpreter would have a real O_RDONLY file descriptor for the >> > underlying file). >> >> For fsck sake, folks, if you have bloody /proc, you don't need that shite >> at all! Just do execve on /proc/self/fd/n, and be done with that. >> >> The sole excuse for merging that thing in the first place had been >> "would anybody think of children^Wsclerotic^Whardened environments >> where they have no /proc at all". > > That doesn't work. With O_CLOEXEC, /proc/self/fd/n is already gone at > the time the interpreter runs, whether you're using fexecveat or > execve with "/proc/self/fd/n" to implement POSIX fexecve(). That's the > problem. This breaks the intended idiom for fexecve. O_CLOEXEC with a #! intepreter can not work. If the file descriptor is closed a #! interpreter can not open it. So I don't know why or how you want that to work but it is nonsense. This certainly does not break the intended usage for execveat. Eric -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
