New check: check_cmd_dmesg()

This check, requested by Mike Dubman <[email protected]>, both
addresses a user suggestion/critique *and* provides a working example
of how to write checks that wrap the built-in check_cmd_output()
function.  With the recently added improvements to the aforementioned
check, wrappers can now provide customized and/or user-defined
messages for each match string.  check_cmd_dmesg() takes advantage of
this capability to allow the user to detect certain error messages
that might appear in "dmesg" output and display a unique check failure
message for each one.

The syntax for check_cmd_dmesg() (and check_cmd_output() too) is:

  check_cmd_dmesg [-r rc] [-t tm] [-e cmd] [-M msg] [-m mstr] [...]

where:

  -r rc    Expect cmd to return rc; fail if it doesn't
  -t tm    Time out cmd after tm seconds
  -e cmd   Use "cmd" instead of "dmesg" as the command to run
  -M msg   Use "msg" as the error message for corresponding mstr
  -m mstr  Match string (most likely negated) to check "cmd" output

You can specify "-M msg" and "-m mstr" multiple times to perform
multiple matches.  If specified and non-empty, the 1st msg corresponds
to the 1st mstr, the 2nd msg to the 2nd mstr, and so on.  Values
supplied for msg can use replaceables %m for mstr, %c for cmd, %l for
the line number of the match (for negated mstr only), and %L for
the entire matching line (again, for negated match strings only).  If
multiple match strings are given, %f can be used to show how many
match strings failed.

In the case of check_cmd_dmesg(), the user will typically want to
supply a negated match string (e.g., "-m '!/segfault at/'") since
they'll almost always be looking for a string that *shouldn't* appear.

(In fact, perhaps check_cmd_dmesg() should add the ! if it's not
there?  Thoughts?)

TODO:  Cache dmesg output so it's only called once?

Author: Michael Jennings

scripts/lbnl_cmd.nhc

@@ -12,7 +12,6 @@ function check_cmd_output() {
     local LINENO=0 MATCH_CNT=0 NEG_MATCH_CNT=0 i
     local -a CMD_LIST LINES MATCHES MATCHED MSGS
 
-    MATCHES=( )
     OPTIND=1
     while getopts ":C:M:O:e:m:r:t:" OPTION ; do
         case "$OPTION" in
@@ -81,6 +80,7 @@ function check_cmd_output() {
                         MSG=${MSGS[$i]:-\"%m\" matched at line %l of \"%c\"}
                         MSG=${MSG//\%m/${MATCHES[$i]:1}}
                         MSG=${MSG//\%l/$((LINENO+1))}
+                        MSG=${MSG//\%L/${LINES[$LINENO]//[\"\`\$]}}
                         MSG=${MSG//\%c/$CMD}
                         die 1 "$CHECKNAME:  $MSG."
                         return 1
@@ -182,3 +182,25 @@ function check_cmd_status() {
     fi
     return 0
 }
+
+# Check dmesg output for matching lines.  Fairly simple wrapper for check_cmd_output() (above).
+function check_cmd_dmesg() {
+    local CMD_TIMEOUT CMD_RETVAL CMD="dmesg"
+    local -a MATCHES MSGS
+
+    OPTIND=1
+    while getopts ":M:e:m:r:t:" OPTION ; do
+        case "$OPTION" in
+            M) MSGS[${#MSGS[*]}]=-M ; MSGS[${#MSGS[*]}]="$OPTARG" ;;
+            e) CMD="$OPTARG" ;;
+            m) MATCHES[${#MATCHES[*]}]=-m ; MATCHES[${#MATCHES[*]}]="$OPTARG" ;;
+            r) CMD_RETVAL="$OPTARG" ;;
+            t) CMD_TIMEOUT="$OPTARG" ;;
+            :) die 1 "$FUNCNAME:  Option -$OPTARG requires an argument." ; return 1 ;;
+            \?) die 1 "$FUNCNAME:  Invalid option:  -$OPTARG" ; return 1 ;;
+        esac
+    done
+    shift $((OPTIND-1))
+
+    check_cmd_output -C $FUNCNAME ${CMD_RETVAL:+-r $CMD_RETVAL} ${CMD_TIMEOUT:+-t $CMD_TIMEOUT} -e "$CMD" "${MSGS[@]}" "${MATCHES[@]}"
+}