Fix --ftrace with cosmo_dlopen()

This change ensures function call logging won't crash the process when cosmo_dlopen() is called.
jart · Jan 5, 2024 · 2d93788 · 2d93788
1 parent 15548b5
commit 2d93788
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Showing 8 changed files with 35 additions and 7 deletions.
diff --git a/libc/dlopen/dlopen.c b/libc/dlopen/dlopen.c
@@ -291,7 +291,7 @@ static wontreturn dontinstrument void foreign_helper(void **p) {
   __foreign.dlsym = p[1];
   __foreign.dlclose = p[2];
   __foreign.dlerror = p[3];
-  longjmp(__foreign.jb, 1);
+  _longjmp(__foreign.jb, 1);
 }
 
 static dontinline void elf_exec(const char *file, char **envp) {

diff --git a/libc/nexgen32e/longjmp.S b/libc/nexgen32e/longjmp.S
@@ -28,6 +28,7 @@
 	.ftrace1
 longjmp:
 	.ftrace2
+_longjmp:
 #ifdef __x86_64__
 	mov	%esi,%eax
 	test	%eax,%eax
@@ -61,5 +62,5 @@ longjmp:
 #error "unsupported architecture"
 #endif
 	.endfn	longjmp,globl
-	.alias	longjmp,_longjmp
+	.endfn	_longjmp,globl
 	.alias	longjmp,siglongjmp
diff --git a/libc/runtime/set_tls-sysv.S b/libc/runtime/set_tls-sysv.S
@@ -0,0 +1,26 @@
+/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8     -*-│
+│ vi: set et ft=asm ts=8 tw=8 fenc=utf-8                                   :vi │
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2024 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/macros.internal.h"
+
+//	we can't allow ftrace here since ftrace needs tls
+sys_set_tls:
+	mov	__NR_set_tls(%rip),%eax
+	syscall
+	ret
+	.endfn	sys_set_tls,globl
diff --git a/libc/runtime/set_tls.c b/libc/runtime/set_tls.c
@@ -28,12 +28,13 @@
 
 int sys_set_tls();
 
-textstartup void __set_tls(struct CosmoTib *tib) {
+// we can't allow --ftrace here because cosmo_dlopen() calls this
+// function to fix the tls register, and ftrace needs it unbroken
+dontinstrument textstartup void __set_tls(struct CosmoTib *tib) {
   tib = __adj_tls(tib);
 #ifdef __x86_64__
   // ask the operating system to change the x86 segment register
   if (IsWindows()) {
-    npassert(0 <= __tls_index && __tls_index < 64);
     asm("mov\t%1,%%gs:%0" : "=m"(*((long *)0x1480 + __tls_index)) : "r"(tib));
   } else if (IsFreebsd()) {
     sys_set_tls(129 /*AMD64_SET_FSBASE*/, tib);

diff --git a/libc/sysv/calls/sys_set_tls.S b/libc/sysv/calls/sys_set_tls.S
diff --git a/libc/sysv/consts.sh b/libc/sysv/consts.sh
@@ -1725,6 +1725,7 @@ syscon	nr	__NR_ioperm				0x00ad			0x0fff			0xfff			0xfff			0xfff			0xfff			0xfff
 syscon	nr	__NR_init_module			0x00af			0x0069			0xfff			0xfff			0xfff			0xfff			0xfff			0xfff
 syscon	nr	__NR_delete_module			0x00b0			0x006a			0xfff			0xfff			0xfff			0xfff			0xfff			0xfff
 syscon	nr	__NR_gettid				0x00ba			0x00b2			0x100001b		0xfff			432			299			311			0xfff		# TODO(jart): thread_self_trap vs. gettid?
+syscon	nr	__NR_set_tls				0x009e			0xfff			0x3000003		0xfff			0x00a5			0x0149			0x13d			0xfff
 syscon	nr	__NR_readahead				0x00bb			0x00d5			0xfff			0xfff			0xfff			0xfff			0xfff			0xfff
 syscon	nr	__NR_setxattr				0x00bc			0x0005			0x20000ec		0x00ec			0xfff			0xfff			0x177			0xfff
 syscon	nr	__NR_fsetxattr				0x00be			0x0007			0x20000ed		0x00ed			0xfff			0xfff			0x179			0xfff

diff --git a/libc/sysv/consts/__NR_set_tls.S b/libc/sysv/consts/__NR_set_tls.S
@@ -0,0 +1,2 @@
+#include "libc/sysv/consts/syscon.internal.h"
+.syscon nr,__NR_set_tls,0x009e,0xfff,0x3000003,0xfff,0x00a5,0x0149,0x13d,0xfff
diff --git a/libc/sysv/syscalls.sh b/libc/sysv/syscalls.sh
@@ -201,7 +201,6 @@ scall	sys_modify_ldt		0xfffffffffffff09a	0xfff	globl # no wrapper
 scall	sys_pivot_root		0xfffffffffffff09b	0x029	globl hidden
 #scall	prctl			0xfffffffffffff09d	0x0a7	globl # wrapped manually
 scall	sys_arch_prctl		0x0a50a50a5ffff09e	0xfff	globl hidden # sysarch() on bsd
-scall	sys_set_tls		0x13d1490a5300309e	0xfff	globl hidden # arch_prctl on linux, sysarch on freebsd, _lwp_setprivate on netbsd, __set_tcb on openbsd, _lwp_setprivate on netbsd, thread_fast_set_cthread_self on xnu
 scall	sys_adjtimex		0xfffffffffffff09f	0x0ab	globl # no wrapper
 scall	sys_swapon		0xffffff05520550a7	0x0e0	globl # no wrapper
 scall	sys_swapoff		0xffffff1a8ffff0a8	0x0e1	globl # no wrapper
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		#include "libc/sysv/consts/syscon.internal.h"
		.syscon nr,__NR_set_tls,0x009e,0xfff,0x3000003,0xfff,0x00a5,0x0149,0x13d,0xfff