mirror of
https://github.com/jart/cosmopolitan.git
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b01282e23e
This reduces the virtual memory usage of Emacs for me by 30%. We now have a simpler implementation that uses read(), rather mmap()ing the whole executable.
250 lines
8.5 KiB
C
250 lines
8.5 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 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/calls/blocksigs.internal.h"
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#include "libc/calls/calls.h"
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#include "libc/calls/internal.h"
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#include "libc/calls/struct/fd.internal.h"
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#include "libc/errno.h"
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#include "libc/intrin/asan.internal.h"
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#include "libc/intrin/asancodes.h"
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#include "libc/intrin/atomic.h"
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#include "libc/intrin/cmpxchg.h"
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#include "libc/intrin/extend.internal.h"
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#include "libc/intrin/strace.internal.h"
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#include "libc/intrin/weaken.h"
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#include "libc/runtime/internal.h"
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#include "libc/runtime/memtrack.internal.h"
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#include "libc/runtime/zipos.internal.h"
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#include "libc/str/str.h"
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#include "libc/sysv/consts/at.h"
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#include "libc/sysv/consts/map.h"
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#include "libc/sysv/consts/o.h"
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#include "libc/sysv/consts/s.h"
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#include "libc/sysv/errfuns.h"
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#include "libc/thread/thread.h"
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#include "libc/zip.internal.h"
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#include "third_party/zlib/zconf.h"
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#include "third_party/zlib/zlib.h"
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static bool __zipos_method_is_supported(int method) {
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switch (method) {
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case kZipCompressionNone:
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case kZipCompressionDeflate:
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return true;
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default:
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return false;
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}
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}
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static void *__zipos_mmap_space(struct Zipos *zipos, size_t mapsize) {
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char *start;
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size_t offset;
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offset = zipos->maptotal;
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zipos->maptotal += mapsize;
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start = (char *)kMemtrackZiposStart;
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if (!zipos->mapend) zipos->mapend = start;
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zipos->mapend = _extend(start, zipos->maptotal, zipos->mapend, MAP_PRIVATE,
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kMemtrackZiposStart + kMemtrackZiposSize);
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return start + offset;
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}
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void __zipos_free(struct ZiposHandle *h) {
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if (!h) return;
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if (IsAsan()) {
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__asan_poison((char *)h + sizeof(struct ZiposHandle),
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h->mapsize - sizeof(struct ZiposHandle), kAsanHeapFree);
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}
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__zipos_lock();
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do h->next = h->zipos->freelist;
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while (!_cmpxchg(&h->zipos->freelist, h->next, h));
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__zipos_unlock();
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}
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static struct ZiposHandle *__zipos_alloc(struct Zipos *zipos, size_t size) {
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size_t mapsize;
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struct ZiposHandle *h, **ph;
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__zipos_lock();
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mapsize = sizeof(struct ZiposHandle) + size;
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mapsize = ROUNDUP(mapsize, 4096);
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StartOver:
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ph = &zipos->freelist;
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while ((h = *ph)) {
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if (h->mapsize >= mapsize) {
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if (!_cmpxchg(ph, h, h->next)) goto StartOver;
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h->next = 0;
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break;
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}
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ph = &h->next;
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}
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if (!h) {
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h = __zipos_mmap_space(zipos, mapsize);
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}
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__zipos_unlock();
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if (IsAsan()) {
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__asan_unpoison((char *)h, sizeof(struct ZiposHandle) + size);
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__asan_poison((char *)h + sizeof(struct ZiposHandle) + size,
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mapsize - (sizeof(struct ZiposHandle) + size),
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kAsanHeapOverrun);
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}
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if (h) {
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h->size = size;
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h->zipos = zipos;
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h->mapsize = mapsize;
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}
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return h;
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}
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static int __zipos_load_fd(struct Zipos *zipos, int cf, int fd,
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struct ZiposUri *name,
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struct ZiposHandle **out_handle) {
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uint64_t size;
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struct ZiposHandle *h;
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if (cf == ZIPOS_SYNTHETIC_DIRECTORY) {
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size = name->len;
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if (!(h = __zipos_alloc(zipos, size + 1))) return -1;
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if (size) memcpy(h->data, name->path, size);
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h->data[size] = 0;
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} else {
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uint8_t lfile[kZipLfileHdrMinSize];
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uint64_t lf = GetZipCfileOffset(zipos->cdir + cf);
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int compressed = ZIP_CFILE_COMPRESSIONMETHOD(zipos->cdir + cf);
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if (!__zipos_method_is_supported(compressed) ||
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pread(fd, lfile, kZipLfileHdrMinSize, lf) != kZipLfileHdrMinSize ||
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ZIP_LFILE_MAGIC(lfile) != kZipLfileHdrMagic) {
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return eio(); // this corruption
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}
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size = GetZipCfileUncompressedSize(zipos->cdir + cf);
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if (!(h = __zipos_alloc(zipos, size))) return -1;
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uint64_t off = lf + ZIP_LFILE_HDRSIZE(lfile);
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if (!compressed) {
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if (pread(fd, h->data, size, off) != size) {
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__zipos_free(h);
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return eio();
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}
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} else {
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struct ZiposHandle *h2;
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uint64_t compsize = GetZipCfileCompressedSize(zipos->cdir + cf);
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if (!(h2 = __zipos_alloc(zipos, compsize))) {
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__zipos_free(h);
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return -1;
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}
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if (pread(fd, h2->data, compsize, off) != compsize ||
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__inflate(h->data, size, h2->data, compsize)) {
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__zipos_free(h2);
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__zipos_free(h);
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return eio();
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}
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__zipos_free(h2);
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}
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}
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h->pos = 0;
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h->cfile = cf;
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h->size = size;
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*out_handle = h;
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return 0;
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}
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static int __zipos_load(struct Zipos *zipos, int cf, int flags,
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struct ZiposUri *name) {
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int fd;
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if ((fd = openat(AT_FDCWD, zipos->progpath,
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O_RDONLY | O_CLOEXEC |
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(flags & (O_NONBLOCK | O_RANDOM | O_SEQUENTIAL)),
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0)) != -1) {
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struct ZiposHandle *h = 0;
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if (__zipos_load_fd(zipos, cf, fd, name, &h) != -1) {
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if (!IsWindows() && !IsMetal()) {
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// unix doesn't use the g_fds table by default, so we need to
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// explicitly ensure an entry exists for our new open()d file
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__ensurefds(fd);
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}
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// turn it from a file fd to a zip fd
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// layer the handle on windows so it can be restored on close
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h->handle = g_fds.p[fd].handle;
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g_fds.p[fd].kind = kFdZip;
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g_fds.p[fd].handle = (intptr_t)h;
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g_fds.p[fd].flags &= ~O_CLOEXEC;
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g_fds.p[fd].flags |= flags & O_CLOEXEC;
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return fd;
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} else {
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close(fd);
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return -1;
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}
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} else {
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return -1;
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}
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}
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/**
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* Loads compressed file from αcτµαlly pδrταblε εxεcµταblε object store.
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*
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* @param uri is obtained via __zipos_parseuri()
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* @asyncsignalsafe
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*/
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int __zipos_open(struct ZiposUri *name, int flags) {
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// check if this thread is cancelled
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int rc;
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if (_weaken(pthread_testcancel_np) &&
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(rc = _weaken(pthread_testcancel_np)())) {
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errno = rc;
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return -1;
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}
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// validate api usage
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if ((flags & O_CREAT) || //
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(flags & O_TRUNC) || //
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(flags & O_ACCMODE) != O_RDONLY) {
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return erofs();
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}
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if ((flags & ~(O_CLOEXEC | O_NONBLOCK | O_NOFOLLOW | O_NOCTTY | O_DIRECTORY |
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O_NOATIME | O_RANDOM | O_SEQUENTIAL))) {
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return einval();
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}
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// get the zipos global singleton
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struct Zipos *zipos;
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if (!(zipos = __zipos_get())) {
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return enoexec();
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}
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// most open() calls are due to languages path searching assets. the
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// majority of these calls will return ENOENT or ENOTDIR. we need to
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// perform two extremely costly sigprocmask() calls below. thanks to
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// zipos being a read-only filesystem, we can avoid it in many cases
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int cf;
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if ((cf = __zipos_find(zipos, name)) == -1) {
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return -1;
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}
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if (cf != ZIPOS_SYNTHETIC_DIRECTORY) {
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int mode = GetZipCfileMode(zipos->cdir + cf);
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if ((flags & O_DIRECTORY) && !S_ISDIR(mode)) {
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return enotdir();
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}
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if (!(mode & 0444)) {
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return eacces();
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}
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}
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// now do the heavy lifting
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BLOCK_SIGNALS;
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rc = __zipos_load(zipos, cf, flags, name);
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ALLOW_SIGNALS;
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return rc;
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}
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