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Improve debug binary location detection

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Justine Tunney 2023-11-16 23:26:05 -08:00
parent 68c7c9c1e0
commit 7a9e176ecf
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17 changed files with 92 additions and 50 deletions
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libc/runtime/finddebugbinary.c
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@ -1,92 +0,0 @@
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 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 "ape/sections.internal.h"
#include "libc/atomic.h"
#include "libc/calls/blockcancel.internal.h"
#include "libc/calls/calls.h"
#include "libc/cosmo.h"
#include "libc/elf/tinyelf.internal.h"
#include "libc/errno.h"
#include "libc/intrin/bits.h"
#include "libc/macros.internal.h"
#include "libc/runtime/runtime.h"
#include "libc/runtime/symbols.internal.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/o.h"
#include "libc/sysv/consts/prot.h"
static struct {
atomic_uint once;
const char *res;
char buf[PATH_MAX];
} g_comdbg;
static bool IsMyDebugBinary(const char *path) {
void *map;
int64_t size;
uintptr_t value;
bool res = false;
int fd, e = errno;
BLOCK_CANCELATION;
if ((fd = open(path, O_RDONLY | O_CLOEXEC, 0)) != -1) {
// sanity test that this .com.dbg file (1) is an elf image, and (2)
// contains the same number of bytes of code as our .com executable
// which is currently running in memory.
if ((size = lseek(fd, 0, SEEK_END)) != -1 &&
(map = mmap(0, size, PROT_READ, MAP_SHARED, fd, 0)) != MAP_FAILED) {
if (READ32LE((char *)map) == READ32LE("\177ELF") &&
GetElfSymbolValue(map, "_etext", &value)) {
res = !_etext || value == (uintptr_t)_etext;
}
munmap(map, size);
}
close(fd);
}
ALLOW_CANCELATION;
errno = e;
return res;
}
static void FindDebugBinaryInit(void) {
char *p = GetProgramExecutableName();
size_t n = strlen(p);
if ((n > 4 && READ32LE(p + n - 4) == READ32LE(".dbg")) ||
IsMyDebugBinary(p)) {
g_comdbg.res = p;
} else if (n + 4 < ARRAYLEN(g_comdbg.buf)) {
mempcpy(mempcpy(g_comdbg.buf, p, n), ".dbg", 5);
if (IsMyDebugBinary(g_comdbg.buf)) {
g_comdbg.res = g_comdbg.buf;
}
}
if (!g_comdbg.res) {
g_comdbg.res = getenv("COMDBG");
}
}
/**
* Returns path of binary with the debug information, or null.
*
* @return path to debug binary, or NULL
*/
const char *FindDebugBinary(void) {
cosmo_once(&g_comdbg.once, FindDebugBinaryInit);
return g_comdbg.res;
}