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https://github.com/opencontainers/runc.git
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Rodrigo Campos
90f5da651a
Linux repo has under `tools/include/nolibc` very simple include files that we can use to generate very small binaries that don't depend on libc. To make things even better, since Linux 6.6 it supports all the architectures we support in runc, which is just beautiful. The runc-dmz binary on x86_64 before this patch (on my debian host) was taking 636K, with this patch it takes only 8K. Signed-off-by: Rodrigo Campos <rodrigoca@microsoft.com>
62 lines
1.4 KiB
C
62 lines
1.4 KiB
C
/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
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/*
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* C Run Time support for NOLIBC
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* Copyright (C) 2023 Zhangjin Wu <falcon@tinylab.org>
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*/
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#ifndef _NOLIBC_CRT_H
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#define _NOLIBC_CRT_H
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char **environ __attribute__((weak));
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const unsigned long *_auxv __attribute__((weak));
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static void __stack_chk_init(void);
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static void exit(int);
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void _start_c(long *sp)
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{
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long argc;
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char **argv;
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char **envp;
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const unsigned long *auxv;
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/* silence potential warning: conflicting types for 'main' */
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int _nolibc_main(int, char **, char **) __asm__ ("main");
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/* initialize stack protector */
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__stack_chk_init();
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/*
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* sp : argc <-- argument count, required by main()
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* argv: argv[0] <-- argument vector, required by main()
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* argv[1]
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* ...
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* argv[argc-1]
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* null
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* environ: environ[0] <-- environment variables, required by main() and getenv()
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* environ[1]
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* ...
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* null
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* _auxv: _auxv[0] <-- auxiliary vector, required by getauxval()
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* _auxv[1]
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* ...
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* null
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*/
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/* assign argc and argv */
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argc = *sp;
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argv = (void *)(sp + 1);
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/* find environ */
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environ = envp = argv + argc + 1;
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/* find _auxv */
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for (auxv = (void *)envp; *auxv++;)
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;
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_auxv = auxv;
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/* go to application */
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exit(_nolibc_main(argc, argv, envp));
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}
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#endif /* _NOLIBC_CRT_H */
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