Start factoring out Unix assumptions

This splits files and adds new identifiers in preperation for supporting
windows, but no Windows-specific code is actually added yet.

src/libstore/build/local-derivation-goal.cc

@@ -17,7 +17,6 @@
 #include "cgroup.hh"
 #include "personality.hh"
 #include "current-process.hh"
-#include "namespaces.hh"
 #include "child.hh"
 #include "unix-domain-socket.hh"
 #include "posix-fs-canonicalise.hh"
@@ -40,18 +39,19 @@
 
 /* Includes required for chroot support. */
 #if __linux__
-#include <sys/ioctl.h>
-#include <net/if.h>
-#include <netinet/ip.h>
-#include <sys/mman.h>
-#include <sched.h>
-#include <sys/param.h>
-#include <sys/mount.h>
-#include <sys/syscall.h>
-#if HAVE_SECCOMP
-#include <seccomp.h>
-#endif
-#define pivot_root(new_root, put_old) (syscall(SYS_pivot_root, new_root, put_old))
+# include <sys/ioctl.h>
+# include <net/if.h>
+# include <netinet/ip.h>
+# include <sys/mman.h>
+# include <sched.h>
+# include <sys/param.h>
+# include <sys/mount.h>
+# include <sys/syscall.h>
+# include "namespaces.hh"
+# if HAVE_SECCOMP
+#   include <seccomp.h>
+# endif
+# define pivot_root(new_root, put_old) (syscall(SYS_pivot_root, new_root, put_old))
 #endif
 
 #if __APPLE__

src/libstore/filetransfer.cc

@@ -1,5 +1,4 @@
 #include "filetransfer.hh"
-#include "namespaces.hh"
 #include "globals.hh"
 #include "store-api.hh"
 #include "s3.hh"
@@ -12,6 +11,10 @@
 #include <aws/core/client/ClientConfiguration.h>
 #endif
 
+#if __linux__
+# include "namespaces.hh"
+#endif
+
 #include <unistd.h>
 #include <fcntl.h>
 
@@ -568,7 +571,9 @@ struct curlFileTransfer : public FileTransfer
             stopWorkerThread();
         });
 
+        #if __linux__
         unshareFilesystem();
+        #endif
 
         std::map<CURL *, std::shared_ptr<TransferItem>> items;
 

src/libutil/current-process.cc

@@ -2,7 +2,6 @@
 #include <cstring>
 
 #include "current-process.hh"
-#include "namespaces.hh"
 #include "util.hh"
 #include "finally.hh"
 #include "file-system.hh"
@@ -17,6 +16,7 @@
 # include <mutex>
 # include <sys/resource.h>
 # include "cgroup.hh"
+# include "namespaces.hh"
 #endif
 
 #include <sys/mount.h>
@@ -84,7 +84,9 @@ void restoreProcessContext(bool restoreMounts)
 {
     restoreSignals();
     if (restoreMounts) {
+        #if __linux__
         restoreMountNamespace();
+        #endif
     }
 
     if (savedStackSize) {

src/libutil/environment-variables.cc

@@ -32,18 +32,4 @@ std::map<std::string, std::string> getEnv()
     return env;
 }
 
-
-void clearEnv()
-{
-    for (auto & name : getEnv())
-        unsetenv(name.first.c_str());
-}
-
-void replaceEnv(const std::map<std::string, std::string> & newEnv)
-{
-    clearEnv();
-    for (auto & newEnvVar : newEnv)
-        setenv(newEnvVar.first.c_str(), newEnvVar.second.c_str(), 1);
-}
-
 }

src/libutil/file-descriptor.cc

@@ -8,74 +8,14 @@
 
 namespace nix {
 
-std::string readFile(int fd)
-{
-    struct stat st;
-    if (fstat(fd, &st) == -1)
-        throw SysError("statting file");
-
-    return drainFD(fd, true, st.st_size);
-}
-
-
-void readFull(int fd, char * buf, size_t count)
-{
-    while (count) {
-        checkInterrupt();
-        ssize_t res = read(fd, buf, count);
-        if (res == -1) {
-            if (errno == EINTR) continue;
-            throw SysError("reading from file");
-        }
-        if (res == 0) throw EndOfFile("unexpected end-of-file");
-        count -= res;
-        buf += res;
-    }
-}
-
-
-void writeFull(int fd, std::string_view s, bool allowInterrupts)
-{
-    while (!s.empty()) {
-        if (allowInterrupts) checkInterrupt();
-        ssize_t res = write(fd, s.data(), s.size());
-        if (res == -1 && errno != EINTR)
-            throw SysError("writing to file");
-        if (res > 0)
-            s.remove_prefix(res);
-    }
-}
-
-
-std::string readLine(int fd)
-{
-    std::string s;
-    while (1) {
-        checkInterrupt();
-        char ch;
-        // FIXME: inefficient
-        ssize_t rd = read(fd, &ch, 1);
-        if (rd == -1) {
-            if (errno != EINTR)
-                throw SysError("reading a line");
-        } else if (rd == 0)
-            throw EndOfFile("unexpected EOF reading a line");
-        else {
-            if (ch == '\n') return s;
-            s += ch;
-        }
-    }
-}
-
-
-void writeLine(int fd, std::string s)
+void writeLine(Descriptor fd, std::string s)
 {
     s += '\n';
     writeFull(fd, s);
 }
 
 
-std::string drainFD(int fd, bool block, const size_t reserveSize)
+std::string drainFD(Descriptor fd, bool block, const size_t reserveSize)
 {
     // the parser needs two extra bytes to append terminating characters, other users will
     // not care very much about the extra memory.
@@ -85,58 +25,26 @@ std::string drainFD(int fd, bool block, const size_t reserveSize)
 }
 
 
-void drainFD(int fd, Sink & sink, bool block)
-{
-    // silence GCC maybe-uninitialized warning in finally
-    int saved = 0;
-
-    if (!block) {
-        saved = fcntl(fd, F_GETFL);
-        if (fcntl(fd, F_SETFL, saved | O_NONBLOCK) == -1)
-            throw SysError("making file descriptor non-blocking");
-    }
-
-    Finally finally([&] {
-        if (!block) {
-            if (fcntl(fd, F_SETFL, saved) == -1)
-                throw SysError("making file descriptor blocking");
-        }
-    });
-
-    std::vector<unsigned char> buf(64 * 1024);
-    while (1) {
-        checkInterrupt();
-        ssize_t rd = read(fd, buf.data(), buf.size());
-        if (rd == -1) {
-            if (!block && (errno == EAGAIN || errno == EWOULDBLOCK))
-                break;
-            if (errno != EINTR)
-                throw SysError("reading from file");
-        }
-        else if (rd == 0) break;
-        else sink({reinterpret_cast<char *>(buf.data()), size_t(rd)});
-    }
-}
-
 //////////////////////////////////////////////////////////////////////
 
-AutoCloseFD::AutoCloseFD() : fd{-1} {}
 
+AutoCloseFD::AutoCloseFD() : fd{INVALID_DESCRIPTOR} {}
 
-AutoCloseFD::AutoCloseFD(int fd) : fd{fd} {}
+
+AutoCloseFD::AutoCloseFD(Descriptor fd) : fd{fd} {}
 
 
 AutoCloseFD::AutoCloseFD(AutoCloseFD && that) : fd{that.fd}
 {
-    that.fd = -1;
+    that.fd = INVALID_DESCRIPTOR;
 }
 
 
 AutoCloseFD & AutoCloseFD::operator =(AutoCloseFD && that)
 {
     close();
     fd = that.fd;
-    that.fd = -1;
+    that.fd = INVALID_DESCRIPTOR;
     return *this;
 }
 
@@ -151,64 +59,54 @@ AutoCloseFD::~AutoCloseFD()
 }
 
 
-int AutoCloseFD::get() const
+Descriptor AutoCloseFD::get() const
 {
     return fd;
 }
 
 
 void AutoCloseFD::close()
 {
-    if (fd != -1) {
-        if (::close(fd) == -1)
+    if (fd != INVALID_DESCRIPTOR) {
+        if(::close(fd) == -1)
             /* This should never happen. */
             throw SysError("closing file descriptor %1%", fd);
-        fd = -1;
+        fd = INVALID_DESCRIPTOR;
     }
 }
 
 void AutoCloseFD::fsync()
 {
-  if (fd != -1) {
-      int result;
+    if (fd != INVALID_DESCRIPTOR) {
+        int result;
+        result =
 #if __APPLE__
-      result = ::fcntl(fd, F_FULLFSYNC);
+            ::fcntl(fd, F_FULLFSYNC)
 #else
-      result = ::fsync(fd);
+            ::fsync(fd)
 #endif
-      if (result == -1)
-          throw SysError("fsync file descriptor %1%", fd);
-  }
+            ;
+        if (result == -1)
+            throw SysError("fsync file descriptor %1%", fd);
+    }
 }
 
 
 AutoCloseFD::operator bool() const
 {
-    return fd != -1;
+    return fd != INVALID_DESCRIPTOR;
 }
 
 
-int AutoCloseFD::release()
+Descriptor AutoCloseFD::release()
 {
-    int oldFD = fd;
-    fd = -1;
+    Descriptor oldFD = fd;
+    fd = INVALID_DESCRIPTOR;
     return oldFD;
 }
 
 
-void Pipe::create()
-{
-    int fds[2];
-#if HAVE_PIPE2
-    if (pipe2(fds, O_CLOEXEC) != 0) throw SysError("creating pipe");
-#else
-    if (pipe(fds) != 0) throw SysError("creating pipe");
-    closeOnExec(fds[0]);
-    closeOnExec(fds[1]);
-#endif
-    readSide = fds[0];
-    writeSide = fds[1];
-}
+//////////////////////////////////////////////////////////////////////
 
 
 void Pipe::close()
@@ -217,38 +115,4 @@ void Pipe::close()
     writeSide.close();
 }
 
-//////////////////////////////////////////////////////////////////////
-
-void closeMostFDs(const std::set<int> & exceptions)
-{
-#if __linux__
-    try {
-        for (auto & s : readDirectory("/proc/self/fd")) {
-            auto fd = std::stoi(s.name);
-            if (!exceptions.count(fd)) {
-                debug("closing leaked FD %d", fd);
-                close(fd);
-            }
-        }
-        return;
-    } catch (SystemError &) {
-    }
-#endif
-
-    int maxFD = 0;
-    maxFD = sysconf(_SC_OPEN_MAX);
-    for (int fd = 0; fd < maxFD; ++fd)
-        if (!exceptions.count(fd))
-            close(fd); /* ignore result */
-}
-
-
-void closeOnExec(int fd)
-{
-    int prev;
-    if ((prev = fcntl(fd, F_GETFD, 0)) == -1 ||
-        fcntl(fd, F_SETFD, prev | FD_CLOEXEC) == -1)
-        throw SysError("setting close-on-exec flag");
-}
-
 }