Improved temporary directory checking in installer and updater. (#9797)

Update temporary directory checking in installer.

This updates the checks that our installer and updater make to choose
what to use for a temporary directory to be both more robust and more
portable.

The new checks use the following logic:

* For each directory to be checked, verify that it is both writable by
  the current user, and that the current user can execute files they
  write there.
* If `$TMPDIR` is set, preferentially use that.
* If that fials, try `/tmp`.
* If that also fails, fall back to `$PWD`.
* If all checks fail, bail early with an explanation instead of failing
  when we first tryto do things with the directory.

It also adds the same checks to the `netdata-installer.sh` script, which
was previously completely missing them.

1 files changed, 41 insertions, 0 deletions

diff --git a/netdata-installer.sh b/netdata-installer.sh
index bc2e1cbe0b..c40d03473e 100755
--- a/netdata-installer.sh
+++ b/netdata-installer.sh
@@ -42,6 +42,43 @@ fi
 cd "${NETDATA_SOURCE_DIR}" || exit 1
 
 # -----------------------------------------------------------------------------
+# figure out an appropriate temporary directory
+_cannot_use_tmpdir() {
+  local testfile ret
+  testfile="$(TMPDIR="${1}" mktemp -q -t netdata-test.XXXXXXXXXX)"
+  ret=0
+
+  if [ -z "${testfile}" ] ; then
+    return "${ret}"
+  fi
+
+  if /bin/echo -e '#!/bin/sh\necho SUCCESS\n' > "${testfile}" ; then
+    if chmod +x "${testfile}" ; then
+      if [ "$("${testfile}")" = "SUCCESS" ] ; then
+        ret=1
+      fi
+    fi
+  fi
+
+  rm -f "${testfile}"
+  return "${ret}"
+}
+
+if [ -z "${TMPDIR}" ] || _cannot_use_tmpdir "${TMPDIR}" ; then
+  if _cannot_use_tmpdir /tmp ; then
+    if _cannot_use_tmpdir "${PWD}" ; then
+      echo >&2
+      echo >&2 "Unable to find a usable temprorary directory. Please set \$TMPDIR to a path that is both writable and allows execution of files and try again."
+      exit 1
+    else
+      TMPDIR="${PWD}"
+    fi
+  else
+    TMPDIR="/tmp"
+  fi
+fi
+
+# -----------------------------------------------------------------------------
 # set up handling for deferred error messages
 NETDATA_DEFERRED_ERRORS=""
 
@@ -324,6 +361,10 @@ cat << BANNER1
 
   You are about to build and install netdata to your system.
 
+  The build process will use ${TPUT_CYAN}${TMPDIR}${TPUT_RESET} for
+  any temporary files. You can override this by setting \$TMPDIR to a
+  writable directory where you can execute files.
+
   It will be installed at these locations:
 
    - the daemon     at ${TPUT_CYAN}${NETDATA_PREFIX}/usr/sbin/netdata${TPUT_RESET}