mirror of
https://github.com/jart/cosmopolitan.git
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6f7d0cb1c3
This makes breaking changes to add underscores to many non-standard function names provided by the c library. MODE=tiny is now tinier and we now use smaller locks that are better for tiny apps in this mode. Some headers have been renamed to be in the same folder as the build package, so it'll be easier to know which build dependency is needed. Certain old misguided interfaces have been removed. Intel intrinsics headers are now listed in libc/isystem (but not in the amalgamation) to help further improve open source compatibility. Header complexity has also been reduced. Lastly, more shell scripts are now available.
105 lines
3.8 KiB
ArmAsm
105 lines
3.8 KiB
ArmAsm
/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8 -*-│
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│vi: set et ft=asm ts=8 tw=8 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/dce.h"
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#include "libc/intrin/strace.internal.h"
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#include "libc/macros.internal.h"
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.privileged
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// Forks process without copying page tables.
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//
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// This is the same as fork() except it's optimized for the case
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// where the caller invokes execve() immediately afterwards. You
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// can also call functions like close(), dup2(), etc. You cannot
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// call read() safely but you can call pread(). Call _exit() but
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// don't call exit(). Look for the vforksafe function annotation
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//
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// Do not make the assumption that the parent is suspended until
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// the child terminates since this impl calls fork() on Windows.
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//
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// @return pid of child process or 0 if forked process
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// @returnstwice
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// @vforksafe
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vfork:
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#ifdef __SANITIZE_ADDRESS__
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jmp fork # TODO: asan and vfork don't mix?
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.endfn vfork,globl
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#else
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#if SupportsWindows()
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testb IsWindows()
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jnz sys_fork_nt # and we're lucky to have that
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#endif
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#if SupportsXnu()
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testb IsXnu()
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jnz fork
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#endif
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#if SupportsOpenbsd()
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testb IsOpenbsd()
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jnz fork # fake vfork plus msyscall issues
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#endif
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#ifdef SYSDEBUG
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ezlea .Llog,di
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call __stracef
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#endif /* SYSDEBUG */
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mov __NR_vfork(%rip),%eax
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mov __errno(%rip),%r8d # avoid question of @vforksafe errno
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pop %rsi # saves return address in a register
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#if SupportsBsd()
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testb IsBsd()
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jnz vfork.bsd
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#endif
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syscall
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push %rsi # note it happens twice in same page
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#if SupportsLinux()
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cmp $-4095,%eax
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jae systemfive_error
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#endif
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0: mov %r8d,__errno(%rip)
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ezlea __vforked,di
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test %eax,%eax
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jz 1f
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decl (%rdi)
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jns 2f # openbsd doesn't actually share mem
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1: incl (%rdi)
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2: ret
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.endfn vfork,globl
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#if SupportsBsd()
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vfork.bsd:
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syscall
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push %rsi
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jc systemfive_errno
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#if SupportsXnu()
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testb IsXnu()
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jz 0b
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neg %edx # edx is 0 for parent and 1 for child
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not %edx # eax always returned with childs pid
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and %edx,%eax
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#endif /* XNU */
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jmp 0b
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.endfn vfork.bsd
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#endif /* BSD */
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#ifdef SYSDEBUG
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.rodata.str1.1
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.Llog: .ascii STRACE_PROLOGUE
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.asciz "vfork()\n"
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.previous
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#endif /* DEBUGSYS */
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#endif /* __SANITIZE_ADDRESS__ */
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