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56 lines
2.9 KiB
C
56 lines
2.9 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2021 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/runtime/runtime.h"
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#include "libc/str/str.h"
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/**
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* Enables plaintext function tracing if `--ftrace` flag is passed.
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*
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* The `--ftrace` CLI arg is removed before main() is called. This code
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* is intended for diagnostic purposes and assumes binaries are
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* trustworthy and stack isn't corrupted. Logging plain text allows
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* program structure to easily be visualized and hotspots identified w/
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* `sed | sort | uniq -c | sort`. A compressed trace can be made by
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* appending `--ftrace 2>&1 | gzip -4 >trace.gz` to the CLI arguments.
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*
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* @see libc/runtime/_init.S for documentation
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*/
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textstartup int ftrace_init(int argc, char *argv[]) {
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int i;
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bool foundflag;
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foundflag = false;
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for (i = 1; i <= argc; ++i) {
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if (!foundflag) {
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if (argv[i]) {
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if (strcmp(argv[i], "--ftrace") == 0) {
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foundflag = true;
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} else if (strcmp(argv[i], "----ftrace") == 0) {
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strcpy(argv[i], "--ftrace");
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}
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}
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} else {
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argv[i - 1] = argv[i];
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}
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}
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if (foundflag) {
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--argc;
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ftrace_install();
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}
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return argc;
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}
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