Option 2: Fix stdin parsing #289
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Checking if data exists in the stdin buffer via an ioctl is unreliable. Allow a user to pass '-' to force stdin parsing. This provides a fix that will allow "no interfaces" to still mean "dump all interfaces". Fixes NetworkConfiguration#285
This was referenced Jan 20, 2024
rsmarples
reviewed
Feb 16, 2024
| @@ -2243,8 +2242,10 @@ main(int argc, char **argv, char **envp) | |||
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| #ifndef SMALL | |||
| if (ctx.options & DHCPCD_DUMPLEASE && | |||
| ioctl(fileno(stdin), FIONREAD, &i, sizeof(i)) == 0 && | |||
| i > 0) | |||
| i > 0 && | |||
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Why checking i > 0? I used to contain the number of bytes in STDIN, now it is undefined as you removed the ioctl which set it.
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You'll need to change dhcpcd.8.in as well to document the new requirement for dumping leases needing the |
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Thanks for the review @rsmarples. I'm busy now, but will try to get back to this PR in the next few weeks if possible. Otherwise I plan circle back to this after the next Ubuntu release. |
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@holmanb Has this made any progress? |
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This is my second fix #285. It checks if there was a single "interface" argument passed and if that argument value is
-. If such an argument exists, then dhcpcd forcibly waits on stdin. This also removes the unreliable "check if the stdin buffer is full" semantics, which I don't think should break other use cases. Runningdhcpcd -U <interface>will work just like it did before, by contacting the network manager[1]. I assume you prefer this fix over the first one I wrote, because that one breaks the "no interface means dump all interfaces" expectation, but I still offered both fixes for you to decide because that documented expectation also appears broken.[1] this requirement also seems like a bug when the lease file has already been acquired with a
--oneshotcall, but as long as we have some stable way across releases to parse a lease without the daemon running I guess I don't care strongly if that one of these gets fixed