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With the startup code moved to C, implementing support for constructors and deconstructors is fairly easy to implement. Examples for code size impact: text data bss dec hex filename 21837 104 88 22029 560d nolibc-test.before 22135 120 88 22343 5747 nolibc-test.after 21970 104 88 22162 5692 nolibc-test.after-only-crt.h-changes The sections are defined by [0]. [0] https://refspecs.linuxfoundation.org/elf/gabi4+/ch5.dynamic.html Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Acked-by: Willy Tarreau <w@1wt.eu> Link: https://lore.kernel.org/lkml/20231007-nolibc-constructors-v2-1-ef84693efbc1@weissschuh.net/
84 lines
2.1 KiB
C
84 lines
2.1 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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extern void (*const __preinit_array_start[])(void) __attribute__((weak));
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extern void (*const __preinit_array_end[])(void) __attribute__((weak));
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extern void (*const __init_array_start[])(void) __attribute__((weak));
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extern void (*const __init_array_end[])(void) __attribute__((weak));
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extern void (*const __fini_array_start[])(void) __attribute__((weak));
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extern void (*const __fini_array_end[])(void) __attribute__((weak));
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__attribute__((weak))
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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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int exitcode;
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void (* const *func)(void);
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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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for (func = __preinit_array_start; func < __preinit_array_end; func++)
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(*func)();
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for (func = __init_array_start; func < __init_array_end; func++)
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(*func)();
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/* go to application */
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exitcode = _nolibc_main(argc, argv, envp);
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for (func = __fini_array_end; func > __fini_array_start;)
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(*--func)();
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exit(exitcode);
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}
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#endif /* _NOLIBC_CRT_H */
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