assimilate via running embedded shell script instead of parsing it

libc/calls/fexecve.c

@@ -33,13 +33,15 @@
 #include "libc/intrin/safemacros.internal.h"
 #include "libc/intrin/strace.internal.h"
 #include "libc/intrin/weaken.h"
+#include "libc/paths.h"
 #include "libc/str/str.h"
 #include "libc/sysv/consts/f.h"
 #include "libc/sysv/consts/fd.h"
 #include "libc/sysv/consts/map.h"
 #include "libc/sysv/consts/mfd.h"
 #include "libc/sysv/consts/o.h"
 #include "libc/sysv/consts/prot.h"
+#include "libc/sysv/consts/s.h"
 #include "libc/sysv/consts/shm.h"
 #include "libc/sysv/errfuns.h"
 
@@ -63,6 +65,57 @@ static int fexecve_impl(const int fd, char *const argv[], char *const envp[]) {
   return rc;
 }
 
+#define defer(fn) __attribute__((cleanup(fn)))
+
+void cleanup_close(int *pFD) {
+  STRACE("time to close");
+  if (*pFD != -1) {
+    close(*pFD);
+  }
+}
+#define defer_close defer(cleanup_close)
+
+void cleanup_unlink(const char **path) {
+  STRACE("time to unlink");
+  if (*path != NULL) {
+    sys_unlink(*path);
+  }
+}
+#define defer_unlink defer(cleanup_unlink)
+
+static bool ape_to_elf_execve(void *ape, const size_t apesize) {
+  if (!_weaken(fork) || !_weaken(exit) || !IsLinux()) {
+    return false;
+  }
+  defer_unlink const char *tempfile = "/dev/shm/ape_to_elf_execve_XXXXXX";
+  defer_close int fd = open(tempfile, O_RDWR | O_CREAT | O_EXCL, S_IRWXU);
+  if (fd == -1) {
+    tempfile = NULL;
+    return false;
+  }
+  if ((sys_ftruncate(fd, apesize, apesize) == -1) || (write(fd, ape, apesize) != apesize)) {
+    return false;
+  }
+  close(fd);
+  fd = -1;
+  int child = _weaken(fork)();
+  if (child == -1) {
+    return false;
+  } else if (child == 0) {
+    __sys_execve(_PATH_BSHELL, (char *const[]){_PATH_BSHELL, tempfile, "--assimilate", NULL}, (char *const[]){NULL});
+    _weaken(exit)(1);
+  }
+  int wstatus;
+  if ((child != waitpid(child, &wstatus, 0)) || !WIFEXITED(wstatus) || (WEXITSTATUS(wstatus) != 0)) {
+    return false;
+  }
+  return ((fd = open(tempfile, O_RDWR, S_IRWXU)) != -1) && (pread(fd, ape, apesize, 0) == apesize);
+}
+
+#undef defer_unlink
+#undef defer_close
+#undef defer
+
 typedef enum {
   PTF_NUM = 1 << 0,
   PTF_NUM2 = 1 << 1,
@@ -71,6 +124,7 @@ typedef enum {
 } PTF_PARSE;
 
 static bool ape_to_elf(void *ape, const size_t apesize) {
+  return ape_to_elf_execve(ape, apesize);
   static const char printftok[] = "printf '";
   static const size_t printftoklen = sizeof(printftok) - 1;
   const char *tok = memmem(ape, apesize, printftok, printftoklen);