mirror of
https://github.com/jart/cosmopolitan.git
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Make fixes and improvements
- Document more compiler flags - Expose new __print_maps() api - Better overflow checking in mmap() - Improve the shell example somewhat - Fix minor runtime bugs regarding stacks - Make kill() on fork()+execve()'d children work - Support CLONE_CHILD_CLEARTID for proper joining - Fix recent possible deadlock regression with --ftrace
This commit is contained in:
Justine Tunney
parent
6e52cba37a
commit
ec2cb88058
68 changed files with 1211 additions and 431 deletions
174
libc/runtime/getsymboltable.c
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174
libc/runtime/getsymboltable.c
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/*-*- 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 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/assert.h"
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#include "libc/bits/bits.h"
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#include "libc/bits/weaken.h"
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#include "libc/calls/strace.internal.h"
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#include "libc/intrin/spinlock.h"
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#include "libc/macros.internal.h"
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#include "libc/runtime/runtime.h"
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#include "libc/runtime/symbols.internal.h"
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#include "libc/str/str.h"
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#include "libc/str/undeflate.h"
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#include "libc/x/x.h"
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#include "libc/zip.h"
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#include "libc/zipos/zipos.internal.h"
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static char g_lock;
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hidden struct SymbolTable *__symtab; // for kprintf
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/**
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* Looks for `.symtab` in zip central directory.
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*/
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static ssize_t FindSymtabInZip(struct Zipos *zipos) {
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size_t i, n, c;
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c = GetZipCdirOffset(zipos->cdir);
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n = GetZipCdirRecords(zipos->cdir);
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for (i = 0; i < n; ++i, c += ZIP_CFILE_HDRSIZE(zipos->map + c)) {
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if (ZIP_CFILE_NAMESIZE(zipos->map + c) == 7 &&
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READ32LE(ZIP_CFILE_NAME(zipos->map + c + 0)) == READ32LE(".sym") &&
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READ16LE(ZIP_CFILE_NAME(zipos->map + c + 4)) == READ16LE("ta") &&
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*ZIP_CFILE_NAME(zipos->map + c + 6) == 'b') {
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return c;
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}
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}
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return -1;
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}
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/**
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* Reads symbol table from zip directory.
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* @note This code can't depend on dlmalloc()
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*/
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static struct SymbolTable *GetSymbolTableFromZip(struct Zipos *zipos) {
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ssize_t rc, cf, lf;
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size_t size, size2;
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struct DeflateState ds;
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struct SymbolTable *res = 0;
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if ((cf = FindSymtabInZip(zipos)) != -1) {
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lf = GetZipCfileOffset(zipos->map + cf);
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size = GetZipLfileUncompressedSize(zipos->map + lf);
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size2 = ROUNDUP(size, FRAMESIZE);
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if ((res = mapanon(size2))) {
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switch (ZIP_LFILE_COMPRESSIONMETHOD(zipos->map + lf)) {
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case kZipCompressionNone:
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memcpy(res, (void *)ZIP_LFILE_CONTENT(zipos->map + lf), size);
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break;
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#if 0
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// TODO(jart): fix me
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case kZipCompressionDeflate:
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rc = undeflate(res, size, (void *)ZIP_LFILE_CONTENT(zipos->map + lf),
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GetZipLfileCompressedSize(zipos->map + lf), &ds);
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if (rc == -1) {
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munmap(res, size2);
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res = 0;
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}
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break;
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#endif
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default:
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munmap(res, size2);
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res = 0;
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break;
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}
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}
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}
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STRACE("GetSymbolTableFromZip() → %p", res);
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return res;
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}
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/**
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* Reads symbol table from .com.dbg file.
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* @note This code can't depend on dlmalloc()
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*/
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static struct SymbolTable *GetSymbolTableFromElf(void) {
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return OpenSymbolTable(FindDebugBinary());
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}
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/**
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* Returns symbol table singleton.
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*
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* This uses multiple strategies to find the symbol table. The first
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* strategy, depends on whether or not the following is linked:
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*
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* STATIC_YOINK("__zipos_get");
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*
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* In that case, the symbol table may be read from `/zip/.symtab` which
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* is generated by `o//tool/build/symtab.com`. The second strategy is to
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* look for the concomitant `.com.dbg` executable, which may very well
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* be the one currently executing, or it could be placed in the same
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* folder as your `.com` binary, or lastly, it could be explicitly
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* specified via the `COMDBG` environment variable.
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*
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* Function tracing is disabled throughout the duration of this call.
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* Backtraces and other core runtime functionality depend on this.
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*
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* @return symbol table, or NULL w/ errno on first call
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*/
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struct SymbolTable *GetSymbolTable(void) {
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struct Zipos *z;
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if (_trylock(&g_lock)) return 0;
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if (!__symtab && !__isworker) {
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if (weaken(__zipos_get) && (z = weaken(__zipos_get)())) {
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if ((__symtab = GetSymbolTableFromZip(z))) {
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__symtab->names =
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(uint32_t *)((char *)__symtab + __symtab->names_offset);
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__symtab->name_base =
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(char *)((char *)__symtab + __symtab->name_base_offset);
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}
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}
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if (!__symtab) {
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__symtab = GetSymbolTableFromElf();
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}
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}
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_spunlock(&g_lock);
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return __symtab;
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}
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/**
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* Returns low index into symbol table for address.
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*
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* @param t if null will be auto-populated only if already open
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* @return index or -1 if nothing found
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*/
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noinstrument privileged int __get_symbol(struct SymbolTable *t, intptr_t a) {
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// we need privileged because:
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// kprintf is privileged and it depends on this
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// we don't want function tracing because:
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// function tracing depends on this function via kprintf
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unsigned l, m, r, n, k;
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if (!t && __symtab) {
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t = __symtab;
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}
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if (t) {
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l = 0;
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r = n = t->count;
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k = a - t->addr_base;
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while (l < r) {
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m = (l + r) >> 1;
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if (t->symbols[m].y < k) {
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l = m + 1;
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} else {
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r = m;
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}
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}
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if (l < n && t->symbols[l].x <= k && k <= t->symbols[l].y) {
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return l;
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}
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}
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return -1;
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}
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