Clarify gets()/fgets()/ARG_MAX in 1992/gson
By accident I stated that I changed this entry to not use gets() but instead fgets(). This is unfortunately not true because of the way gets() is used. I have now made it (I hope) a bit clearer. I also pointed out that it's theoretically safe. Since it uses gets() which comes from stdin ARG_MAX should be relevant. Thus I made the buffer size ARG_MAX+1. But something I am not so clear on is whether or not ARG_MAX is the entire command line or a single argument. Looking did not help here as some say one thing and others say the other. Doing xargs --show-limits and also checking the value of ARG_MAX suggests that it's for the entire command but I don't know for sure of that. Nevertheless it is safer than it was if not completely safe.
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@@ -14,16 +14,19 @@
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./ag word word2 word3 < /path/to/dictionary
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[Cody Boone Ferguson](/winners.html#Cody_Boone_Ferguson) fixed this entry to not
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use gets(). Previously it had a buffer size of 256 which could easily overflow.
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Now in this entry `gets()` is used in a more complicated way (first `m` is set
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to `*++p` in a for loop where `p` is argv and then later `m` is set to point to
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`h` which is of size 256) and trying to change it to use fgets() proved more a
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problem. Since the input must come from the command line Cody changed the buffer
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size to `ARG_MAX+1` which should be enough especially since the command expects
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redirecting a dictionary file as part of the command line. This also makes it
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possible for longer strings to be read (in case the `gets()` was not used in a
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loop). Thank you Cody for your assistance!
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[Cody Boone Ferguson](/winners.html#Cody_Boone_Ferguson) changed the buffer size
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in such a way that gets() should be safe (theoretically) as it comes from the
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command line. Ideally `fgets()` would be used but this is a more problematic.
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Previously it had a buffer size of 256 which could easily overflow. Now in this
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entry `gets()` is used in a more complicated way. First `m` is set to `*++p` in
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a for loop where `p` is argv and then later `m` is set to point to `h` which is
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of size 256. `gets()` is called as `m = gets(m)`) but trying to change it to use
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fgets() proved more a problem. Since the input must come from the command line
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Cody changed the buffer size to `ARG_MAX+1` which should be enough (again
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theoretically) especially since the command expects redirecting a dictionary
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file as part of the command line. This also makes it possible for longer strings
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to be read (in case the `gets()` was not used in a loop). Thank you Cody for
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your assistance!
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## Judges' comment:
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