Revert conflated fixes for DragonFly CWD.

src/ext/cwd.cpp

@@ -46,10 +46,8 @@
 #endif
 
 #if defined(__DragonFly__)
-#include <climits>
 #include <cstring>
-#include <sys/types.h>
-#include <sys/sysctl.h>
+#include <cstdio>
 #endif
 
 #ifdef BOOST_PROCESS_USE_STD_FS
@@ -154,14 +152,53 @@ filesystem::path cwd(boost::process::v2::pid_type pid, boost::system::error_code
 
 filesystem::path cwd(boost::process::v2::pid_type pid, boost::system::error_code & ec)
 {
+ /*
  filesystem::path path;
- char buffer[PATH_MAX];
- std::size_t sz = 4, len = sizeof(buffer);
+ // Official API (broken OS-level) - including code from DragonFly's fstat(1) 
+ // command line interface utility currently requires way too much code FWIW.
+ std::size_t sz = 4, len = 0;
  int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_CWD, pid};
- if (sysctl(mib, sz, buffer, &len, nullptr, 0) == 0)
+ if (sysctl(mib, sz, nullptr, &len, nullptr, 0) == 0)
+ {
+ std::vector<char> vecbuff;
+ vecbuff.resize(len);
+ if (sysctl(mib, sz, &vecbuff[0], &len, nullptr, 0) == 0)
+ {
+ path = filesystem::canonical(&vecbuff[0], ec);
+ } 
+ else
+ BOOST_PROCESS_V2_ASSIGN_LAST_ERROR(ec)
+ }
+ else
+ BOOST_PROCESS_V2_ASSIGN_LAST_ERROR(ec)
+ return path;
+ */
+
+ filesystem::path path;
+ /* Probably the hackiest thing ever we are doing here, because the official API is broken OS-level. */
+ FILE *fp = popen(("pos=`ans=\\`/usr/bin/fstat -w -p " + std::to_string(pid) + " | /usr/bin/sed -n 1p\\`; " +
+ "/usr/bin/awk -v ans=\"$ans\" 'BEGIN{print index(ans, \"INUM\")}'`; str=`/usr/bin/fstat -w -p " + 
+ std::to_string(pid) + " | /usr/bin/sed -n 3p`; /usr/bin/awk -v str=\"$str\" -v pos=\"$pos\" " +
+ "'BEGIN{print substr(str, 0, pos + 4)}' | /usr/bin/awk 'NF{NF--};1 {$1=$2=$3=$4=\"\"; print" +
+ " substr($0, 5)'}").c_str(), "r");
+ if (fp) 
  {
- path = filesystem::canonical(buffer, ec);
- } 
+ char buffer[PATH_MAX];
+ if (fgets(buffer, sizeof(buffer), fp)) 
+ {
+ std::string str = buffer;
+ std::size_t pos = str.find("\n", strlen(buffer) - 1);
+ if (pos != std::string::npos) 
+ {
+ str.replace(pos, 1, "");
+ }
+ path = filesystem::canonical(str.c_str(), ec);
+ }
+ else
+ BOOST_PROCESS_V2_ASSIGN_LAST_ERROR(ec)
+ if (pclose(fp) == -1)
+ BOOST_PROCESS_V2_ASSIGN_LAST_ERROR(ec)
+ }
  else
  BOOST_PROCESS_V2_ASSIGN_LAST_ERROR(ec)
  return path;