mirror of git://git.musl-libc.org/musl
add support for init/finit (constructors and destructors)
this is mainly in hopes of supporting c++ (not yet possible for other reasons) but will also help applications/libraries which use (and more often, abuse) the gcc __attribute__((__constructor__)) feature in "C" code. x86_64 and arm versions of the new startup asm are untested and may have minor problems.
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@ -1,13 +1,16 @@
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.weak _init
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.weak _fini
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.global _start
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_start:
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mov fp,#0
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mov lr,#0
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ldr a2,[sp],#4
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mov a3,sp
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mov a4,#0
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ldr a4,=_fini
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str fp,[sp,#-4]!
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str a1,[sp,#-4]!
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str fp,[sp,#-4]!
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str a4,[sp,#-4]!
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ldr a4,=_init
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ldr a1,=main
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bl __libc_start_main
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1: b 1b
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@ -0,0 +1,7 @@
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.section .init
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.global _init
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_init:
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.section .fini
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.global _fini
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_fini:
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@ -0,0 +1,9 @@
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.section .init
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tst lr,#1
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moveq pc,lr
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bx lr
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.section .fini
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tst lr,#1
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moveq pc,lr
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bx lr
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@ -1,3 +1,5 @@
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.weak _init
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.weak _fini
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.text
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.global _start
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_start:
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@ -8,8 +10,10 @@ _start:
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pushl %esp
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pushl %esp
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pushl %edx
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pushl %ebp
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pushl %ebp
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call 1f
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1: addl $[_fini-.],(%esp)
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call 1f
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1: addl $[_init-.],(%esp)
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pushl %eax
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pushl %ecx
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call 1f
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@ -0,0 +1,7 @@
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.section .init
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.global _init
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_init:
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.section .fini
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.global _fini
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_fini:
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@ -0,0 +1,5 @@
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.section .init
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ret
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.section .fini
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ret
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@ -1,4 +1,6 @@
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/* Written 2011 Nicholas J. Kain, released as Public Domain */
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.weak _init
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.weak _fini
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.text
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.global _start
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_start:
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@ -9,8 +11,8 @@ _start:
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andq $-16,%rsp /* align stack pointer */
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push %rax /* 8th arg: glibc ABI compatible */
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push %rsp /* 7th arg: glibc ABI compatible */
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xor %r8,%r8 /* 5th arg: always 0 */
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xor %rcx,%rcx /* 4th arg: always 0 */
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mov $_fini,%r8 /* 5th arg: fini/dtors function */
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mov $_init,%rcx /* 4th arg: init/ctors function */
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mov $main,%rdi /* 1st arg: application entry ip */
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call __libc_start_main /* musl init will run the program */
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.L0: jmp .L0
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1: jmp 1b
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@ -0,0 +1,7 @@
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.section .init
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.global _init
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_init:
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.section .fini
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.global _fini
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_fini:
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@ -0,0 +1,5 @@
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.section .init
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ret
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.section .fini
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ret
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@ -49,6 +49,7 @@ struct dso
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ino_t ino;
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int global;
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int relocated;
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int constructed;
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struct dso **deps;
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char *name;
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char buf[];
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@ -471,6 +472,20 @@ static size_t find_dyn(Phdr *ph, size_t cnt, size_t stride)
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return 0;
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}
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static void do_init_fini(struct dso *p)
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{
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size_t dyn[DYN_CNT] = {0};
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for (; p; p=p->prev) {
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if (p->constructed) return;
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decode_vec(p->dynv, dyn, DYN_CNT);
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if (dyn[0] & (1<<DT_FINI))
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atexit((void (*)(void))(p->base + dyn[DT_FINI]));
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if (dyn[0] & (1<<DT_INIT))
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((void (*)(void))(p->base + dyn[DT_INIT]))();
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p->constructed = 1;
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}
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}
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void *__dynlink(int argc, char **argv)
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{
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size_t *auxv, aux[AUX_CNT] = {0};
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@ -520,6 +535,7 @@ void *__dynlink(int argc, char **argv)
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}
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app->name = argv[0];
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app->global = 1;
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app->constructed = 1;
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app->dynv = (void *)(app->base + find_dyn(
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(void *)aux[AT_PHDR], aux[AT_PHNUM], aux[AT_PHENT]));
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decode_dyn(app);
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@ -577,6 +593,9 @@ void *__dynlink(int argc, char **argv)
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* error. If the dynamic loader (dlopen) will not be used, free
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* all memory used by the dynamic linker. */
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runtime = 1;
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do_init_fini(tail);
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if (!rtld_used) {
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free_all(head);
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free(sys_path);
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