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Rewrite ZipOS
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.
This commit is contained in:
Justine Tunney
parent
ff77f2a6af
commit
b01282e23e
21 changed files with 408 additions and 421 deletions
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@ -16,127 +16,89 @@
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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/intrin/bits.h"
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#include "libc/atomic.h"
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#include "libc/calls/calls.h"
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#include "libc/cosmo.h"
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#include "libc/dce.h"
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#include "libc/errno.h"
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#include "libc/intrin/kprintf.h"
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#include "libc/intrin/promises.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/macros.internal.h"
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#include "libc/runtime/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/runtime/zipos.internal.h"
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#include "libc/str/str.h"
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#include "libc/thread/thread.h"
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#include "libc/x/x.h"
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#include "libc/zip.internal.h"
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#include "third_party/puff/puff.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/prot.h"
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__static_yoink("__get_symbol");
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static pthread_spinlock_t g_lock;
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struct SymbolTable *__symtab; // for kprintf
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struct SymbolTableLoader __symtab;
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static ssize_t GetZipFile(struct Zipos *zipos, const char *name) {
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size_t i, n, c, z;
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z = strlen(name);
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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) == z &&
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!memcmp(ZIP_CFILE_NAME(zipos->map + c), name, z)) {
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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 cf, lf;
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size_t size, size2;
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static struct SymbolTable *GetSymbolTableFromZip(void) {
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int fd;
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struct SymbolTable *res = 0;
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if ((cf = GetZipFile(zipos, ".symtab." _ARCH_NAME)) != -1 ||
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(cf = GetZipFile(zipos, ".symtab")) != -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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case kZipCompressionDeflate:
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if (__inflate((void *)res, size,
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(void *)ZIP_LFILE_CONTENT(zipos->map + lf),
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GetZipLfileCompressedSize(zipos->map + lf))) {
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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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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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if ((fd = open("/zip/.symtab." _ARCH_NAME, O_RDONLY)) != -1 ||
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(fd = open("/zip/.symtab", O_RDONLY)) != -1) {
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void *map;
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ssize_t size;
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if ((size = lseek(fd, 0, SEEK_END)) != -1 &&
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(map = mmap(0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0)) !=
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MAP_FAILED) {
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res = map;
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}
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close(fd);
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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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const char *s;
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if (PLEDGED(RPATH) && (s = FindDebugBinary())) {
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return OpenSymbolTable(s);
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const char *path;
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if ((path = FindDebugBinary())) {
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return OpenSymbolTable(path);
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} else {
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return 0;
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}
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}
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static void GetSymbolTableInit(void) {
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if (!PLEDGED(RPATH)) return;
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int e = errno;
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if ((__symtab.st = GetSymbolTableFromZip())) {
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__symtab.st->names =
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(uint32_t *)((char *)__symtab.st + __symtab.st->names_offset);
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__symtab.st->name_base =
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(char *)((char *)__symtab.st + __symtab.st->name_base_offset);
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}
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if (!__symtab.st) {
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__symtab.st = GetSymbolTableFromElf();
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}
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errno = e;
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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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* __static_yoink("zipos");
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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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* In that case, the symbol table may be read from `/zip/.symtab.ARCH`
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* or `/zip/.symtab` which are generated by `o//tool/build/symtab.com`
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* or `o//tool/build/apelink.com`.
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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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* The second strategy is to look for the ELF executable for the current
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* program. If you're running a .com binary, it'll look for the .com.dbg
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* file. If it's running the .com.dbg or .elf file, then it'll just read
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* the symbols from itself. In other cases, you can explicitly specify a
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* debug symbol binary via the `COMDBG` environment variable.
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*
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* When using pledge() security, it's recommended that this function get
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* called *before* calling pledge() if it lacks the rpath promise, so it
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* can load the symbols into memory before the filesystem goes away.
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*
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* @return symbol table, or NULL if not found
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*/
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struct SymbolTable *GetSymbolTable(void) {
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struct Zipos *z;
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if (pthread_spin_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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pthread_spin_unlock(&g_lock);
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return __symtab;
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cosmo_once(&__symtab.once, GetSymbolTableInit);
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return __symtab.st;
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}
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