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Add #define _GNU_SOURCE so that transaction.go can reference C.RTLD_NEXT #35

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Add #define _GNU_SOURCE so that transaction.go can reference C.RTLD_NEXT #35

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5 changes: 5 additions & 0 deletions transaction.go
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,7 @@ package pam
#cgo CFLAGS: -Wall -Wno-unused-variable -std=c99
#cgo LDFLAGS: -ldl -lpam

#define _GNU_SOURCE
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@3v1n0 3v1n0 Sep 9, 2025

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Maybe this should be only in #ifdef __linux__ and other UNIX systems using glibc?

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@3v1n0 3v1n0 Sep 9, 2025

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Otherwise you can define _GNU_SOURCE for all, then you add an #ifndef RTLD_NEXT that sets it to 0 if unset? I'm not aware of platforms where that is not set, but it's safer to go this way.

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@msteinert msteinert Sep 9, 2025

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Or #if defined(__GLIBC__) maybe?

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@astudentofblake astudentofblake Oct 8, 2025

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Sorry for the delayed response

Not obvious what the best solution is here,
GLIBC is defined in features.h, which I could include to test the define, however features.h sets defines based on _GNU_SOURCE, so its not really correct.

I'll update the request with the second suggestion, define _GNU_SOURCE and add the ifndef, from the include file: -

define RTLD_NEXT ((void *) -1l)

I'm assuming this is what you mean (rather than set to zero).

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@astudentofblake astudentofblake Oct 8, 2025

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sorry, the define text being really large is a copy-paste error.

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@szaydel szaydel Oct 23, 2025

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I ran into this issue recently as well. May I suggest placing these changes into transaction_linux.go, and perhaps use #cgo CFLAGS: -D_GNU_SOURCE, which seems to be the preferred method.

#include <dlfcn.h>
#include <security/pam_appl.h>
#include <stdlib.h>
Expand All @@ -18,6 +19,10 @@ package pam
#define BINARY_PROMPT_IS_SUPPORTED 0
#endif

#ifndef RTLD_NEXT
# define RTLD_NEXT ((void *) -1l)
#endif

void init_pam_conv(struct pam_conv *conv, uintptr_t);

typedef int (*pam_start_confdir_fn)(const char *service_name, const char *user, const struct pam_conv *pam_conversation, const char *confdir, pam_handle_t **pamh);
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