cosmopolitan/libc/runtime/isdynamicexecutable.c
Justine Tunney d7c79f43ef
Clean up more code
- Found some bugs in LLVM compiler-rt library
- The useless LIBC_STUBS package is now deleted
- Improve the overflow checking story even further
- Get chibicc tests working in MODE=dbg mode again
- The libc/isystem/ headers now have correctly named guards
2023-06-18 01:00:05 -07:00

81 lines
3.2 KiB
C

/*-*- 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 2022 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 "libc/calls/blockcancel.internal.h"
#include "libc/calls/calls.h"
#include "libc/calls/struct/stat.h"
#include "libc/elf/def.h"
#include "libc/elf/elf.h"
#include "libc/elf/struct/ehdr.h"
#include "libc/elf/struct/phdr.h"
#include "libc/errno.h"
#include "libc/intrin/bits.h"
#include "libc/runtime/runtime.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/o.h"
#include "libc/sysv/consts/prot.h"
/**
* Returns true if ELF executable uses dynamic loading magic.
*/
bool _IsDynamicExecutable(const char *prog) {
bool res;
Elf64_Ehdr *e;
Elf64_Phdr *p;
struct stat st;
int i, fd, err;
BLOCK_CANCELLATIONS;
fd = -1;
err = errno;
e = MAP_FAILED;
if ((fd = open(prog, O_RDONLY)) == -1) {
res = false;
goto Finish;
}
if (fstat(fd, &st) == -1 || st.st_size < 64) {
res = false;
goto Finish;
}
if ((e = mmap(0, st.st_size, PROT_READ, MAP_SHARED, fd, 0)) == MAP_FAILED) {
res = false;
goto Finish;
}
if (READ32LE(e->e_ident) != READ32LE(ELFMAG)) {
res = false;
goto Finish;
}
if (e->e_type == ET_DYN) {
res = true;
goto Finish;
}
for (i = 0; i < e->e_phnum; ++i) {
p = GetElfProgramHeaderAddress(e, st.st_size, i);
if (p->p_type == PT_INTERP || p->p_type == PT_DYNAMIC) {
res = true;
goto Finish;
}
}
res = false;
goto Finish;
Finish:
if (e != MAP_FAILED) munmap(e, st.st_size);
if (fd != -1) close(fd);
errno = err;
ALLOW_CANCELLATIONS;
return res;
}