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authorDavid Lamparter <equinox@diac24.net>2019-11-26 17:05:47 +0100
committerDavid Lamparter <equinox@diac24.net>2019-11-26 17:14:03 +0100
commit50db10a162f5929784f448152c1c0bca11dcd517 (patch)
treefe8af160232ead065fcf4879b73187ae00ddcdb8
parentMerge pull request #5408 from donaldsharp/scan7 (diff)
downloadfrr-50db10a162f5929784f448152c1c0bca11dcd517.tar.xz
frr-50db10a162f5929784f448152c1c0bca11dcd517.zip
lib: add gcc 4.x workaround for frr_interface_info
gcc 4.x does not properly support structs with variable length array members. Specifically, for global variables, it completely ignores the array, coming up with a size much smaller than what is correct. This is broken for both sizeof() as well as ELF object size. This breaks for frr_interface_info since this variable is in some cases copy relocated by the linker. (The linker does this to make the address of the variable a "constant" for the main program.) This copying uses the ELF object size, thereby copying only the non-array part of the struct. Breakage ensues... (This fix is a bit ugly, but it's limited to very old gcc, and it's better than changing the array to "nodes[1000]" and wasting memory...) Fixes: #4563 Fixes: #5074 Signed-off-by: David Lamparter <equinox@diac24.net>
-rw-r--r--lib/if.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/lib/if.c b/lib/if.c
index 9d0f13ecb..f1565a089 100644
--- a/lib/if.c
+++ b/lib/if.c
@@ -1677,3 +1677,13 @@ const struct frr_yang_module_info frr_interface_info = {
},
}
};
+
+#if defined(__GNUC__) && ((__GNUC__ - 0) < 5) && !defined(__clang__)
+/* gcc versions before 5.x miscalculate the size for structs with variable
+ * length arrays (they just count it as size 0)
+ *
+ * NB: the "." below means "current position", i.e. this line must be
+ * immediately after the frr_interface_info variable!
+ */
+__asm__(".size\tfrr_interface_info, .-frr_interface_info\n");
+#endif