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authorWilly Tarreau <w@1wt.eu>2023-01-10 10:24:19 +0300
committerPaul E. McKenney <paulmck@kernel.org>2023-01-11 00:33:55 +0300
commit52e423f5b93e6d30fd5d311f068094b768caffb5 (patch)
tree79f3dd88b312187a050ac2c30a55a3bde5f3e9b6 /tools/include/nolibc
parent89dc50921c87e2b4a4612188c5a90abebc02b60d (diff)
downloadlinux-52e423f5b93e6d30fd5d311f068094b768caffb5.tar.xz
tools/nolibc: export environ as a weak symbol on i386
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 <w@1wt.eu> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'tools/include/nolibc')
-rw-r--r--tools/include/nolibc/arch-i386.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/tools/include/nolibc/arch-i386.h b/tools/include/nolibc/arch-i386.h
index ef2a836ee667..60b586120727 100644
--- a/tools/include/nolibc/arch-i386.h
+++ b/tools/include/nolibc/arch-i386.h
@@ -178,6 +178,8 @@ struct sys_stat_struct {
_eax; \
})
+char **environ __attribute__((weak));
+
/* startup code */
/*
* i386 System V ABI mandates:
@@ -191,6 +193,7 @@ void __attribute__((weak,noreturn,optimize("omit-frame-pointer"))) _start(void)
"pop %eax\n" // argc (first arg, %eax)
"mov %esp, %ebx\n" // argv[] (second arg, %ebx)
"lea 4(%ebx,%eax,4),%ecx\n" // then a NULL then envp (third arg, %ecx)
+ "mov %ecx, environ\n" // save environ
"xor %ebp, %ebp\n" // zero the stack frame
"and $-16, %esp\n" // x86 ABI : esp must be 16-byte aligned before
"sub $4, %esp\n" // the call instruction (args are aligned)