From 9b8688c6eaddcdf0db600953d57beaeafaae1155 Mon Sep 17 00:00:00 2001 From: Willy Tarreau Date: Tue, 10 Jan 2023 08:24:20 +0100 Subject: [PATCH] tools/nolibc: export environ as a weak symbol on arm64 The environ is retrieved from the _start code and is easy to store at this moment. Let's declare the variable weak and store the value into it. By not being static it will be visible to all units. By being weak, if some programs already declared it, they will continue to be able to use it. This was tested both with environ inherited from _start and extracted from envp. Signed-off-by: Willy Tarreau Signed-off-by: Paul E. McKenney --- tools/include/nolibc/arch-aarch64.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/tools/include/nolibc/arch-aarch64.h b/tools/include/nolibc/arch-aarch64.h index f480993159ec..2e3d9adc4c4c 100644 --- a/tools/include/nolibc/arch-aarch64.h +++ b/tools/include/nolibc/arch-aarch64.h @@ -169,6 +169,8 @@ struct sys_stat_struct { _arg1; \ }) +char **environ __attribute__((weak)); + /* startup code */ void __attribute__((weak,noreturn,optimize("omit-frame-pointer"))) _start(void) { @@ -178,6 +180,8 @@ void __attribute__((weak,noreturn,optimize("omit-frame-pointer"))) _start(void) "lsl x2, x0, 3\n" // envp (x2) = 8*argc ... "add x2, x2, 8\n" // + 8 (skip null) "add x2, x2, x1\n" // + argv + "adrp x3, environ\n" // x3 = &environ (high bits) + "str x2, [x3, #:lo12:environ]\n" // store envp into environ "and sp, x1, -16\n" // sp must be 16-byte aligned in the callee "bl main\n" // main() returns the status code, we'll exit with it. "mov x8, 93\n" // NR_exit == 93