[generate_dump] [Mellanox] Fix the duplicate dfw dump collection problem by adding symlinks (sonic-net#2536)

- What I did
Currently the dfw dumps which are usually saved under /var/log/mellanox/sdk-dumps are collect twice in the techsupport. Once under log/ and once under sai_sdk_dump/ folder.

Fixed the scenario by creating a symbolic link from sai_sdk_dump/sai-dfw-xxxxxxxxx.tar.gz -> ../log/sai-dfw-xxxxxxxxx.tar.gz

- How I did it
dfw dumps are copied from syncd currently, but the logic is updated to collect files from the host if SAI_DUMP_STORE_PATH is mounted on the host
Fixed the duplicate dfw dump collection problems by adding a relative symbolic link from sai-sdk-dump/ -> log/ folder.
fw dump me collection is moved to a new function collect_mellanox_dfw_dumps which in run at the end i.e. after the files under /var/log are saved

- How to verify it
root@switch:/home/admin# show techsupport --verbose
root@switch:/home/admin/sonic_dump_r-lionfish-13_20221202_081958/log# ls -Al | grep dfw
-rw-r--r-- 1 root root  1841061 Dec  2 08:21 sai-dfw-1669685690.tar.gz
root@switch:/home/admin/sonic_dump_r-lionfish-13_20221202_081958/sai_sdk_dump# ls -Al

Signed-off-by: Vivek Reddy Karri <[email protected]>

Author: vivekrnv

scripts/generate_dump

@@ -939,6 +939,49 @@ enable_logrotate() {
     sed -i '/\/usr\/sbin\/logrotate/s/^#*//g' /etc/cron.d/logrotate
 }
 
+###############################################################################
+# Create a relative symbolic link of an existing file
+# Globals:
+#  BASE
+#  MKDIR
+#  TAR
+#  TARFILE
+#  DUMPDIR
+#  V
+#  RM
+#  NOOP
+# Arguments:
+#  filename: the full path of the file
+#  dest_dir: destination dir where the link is created
+#  src_sir: directory under $TARDIR where the actual file exists
+# Returns:
+#  None
+###############################################################################
+save_symlink() {
+    trap 'handle_error $? $LINENO' ERR
+    local start_t=$(date +%s%3N)
+    local end_t=0
+    local filename=$1
+    local dest_dir=$2
+    local src_dir=$3
+    local do_tar_append=${4:-true}
+    local file_basename=$(basename $filename)
+    local tar_path="$BASE/$dest_dir/$file_basename"
+
+    $MKDIR $V -p "$TARDIR/$dest_dir"
+
+    ${CMD_PREFIX}pushd $TARDIR/$dest_dir
+    ${CMD_PREFIX}ln -s ../$src_dir/$file_basename $file_basename
+    ${CMD_PREFIX}popd
+
+    if $do_tar_append; then
+        ($TAR $V -rf $TARFILE -C $DUMPDIR "$tar_path" \
+            || abort "${EXT_PROCFS_SAVE_FAILED}" "tar append operation failed. Aborting to prevent data loss.") \
+            && $RM $V -f "$DUMPDIR/$tar_path"
+    fi
+    end_t=$(date +%s%3N)
+    echo "[ save_symlink:$filename] : $(($end_t-$start_t)) msec"  >> $TECHSUPPORT_TIME_INFO
+}
 
 ###############################################################################
 # Collect Mellanox specific information
@@ -971,16 +1014,6 @@ collect_mellanox() {
     ${CMD_PREFIX}rm -rf $sai_dump_folder
     ${CMD_PREFIX}docker exec syncd rm -rf $sai_dump_folder
 
-    # Save SDK error dumps
-    local sdk_dump_path=`${CMD_PREFIX}docker exec syncd cat /tmp/sai.profile|grep "SAI_DUMP_STORE_PATH"|cut -d = -f2`
-    if [[ -d $sdk_dump_path ]]; then
-        copy_from_docker syncd $sdk_dump_path  /tmp/sdk-dumps
-        for file in $(find /tmp/sdk-dumps -type f); do
-            save_file ${file} sai_sdk_dump false
-        done
-        rm -rf /tmp/sdk-dumps
-    fi
-
     # run 'hw-management-generate-dump.sh' script and save the result file
     HW_DUMP_FILE=/usr/bin/hw-management-generate-dump.sh
     if [ -f "$HW_DUMP_FILE" ]; then
@@ -1002,6 +1035,53 @@ collect_mellanox() {
 
 }
 
+###############################################################################
+# Collect dfw dumps if any. Applies to only MLNX platform
+# Globals:
+#  CMD_PREFIX
+# Arguments:
+#  None
+# Returns:
+#  None
+###############################################################################
+collect_mellanox_dfw_dumps() {
+    trap 'handle_error $? $LINENO' ERR
+    local platform=$(python3 -c "from sonic_py_common import device_info; print(device_info.get_platform())")
+    local hwsku=$(python3 -c "from sonic_py_common import device_info; print(device_info.get_hwsku())")
+    local sdk_dump_path=`cat /usr/share/sonic/device/${platform}/${hwsku}/sai.profile|grep "SAI_DUMP_STORE_PATH"|cut -d = -f2`
+
+    if [[ ! -d $sdk_dump_path ]]; then
+       # This would mean the SAI_DUMP_STORE_PATH is not mounted on the host and is only accessible though the container 
+       # This is a bad design and not recommended But there is nothing which restricts against it and thus the special handling
+       if [[ "$( docker container inspect -f '{{.State.Running}}' syncd )" == "true" ]]; then
+            $RM $V -rf /tmp/dfw-sdk-dumps
+            $MKDIR $V -p /tmp/dfw-sdk-dumps
+            copy_from_docker syncd $sdk_dump_path /tmp/dfw-sdk-dumps
+       else
+            echo "ERROR: dfw dumps cannot be collected"
+       fi
+       sdk_dump_path="/tmp/dfw-sdk-dumps"
+    fi
+
+    for file in $(find_files "$sdk_dump_path"); do
+        if $TAR -tf $TARFILE | grep $BASE/log/$(basename $file); then
+            # If this path sits under "/var/log/" dir, the files
+            # would've already been collected and thus just add a sym link
+            if [ ! -z "${file##*.gz}" ]; then
+                # files saved under log/ are zipped with gz
+                file=$file.gz
+            fi
+            ${CMD_PREFIX}save_symlink ${file} sai_sdk_dump log
+        else
+            if [ ! -z "${file##*.gz}" ]; then
+                ${CMD_PREFIX}save_file ${file} sai_sdk_dump true
+            else
+                ${CMD_PREFIX}save_file ${file} sai_sdk_dump false
+            fi
+        fi
+    done
+}
+
 ###############################################################################
 # Collect Broadcom specific information
 # Globals:
@@ -1503,6 +1583,10 @@ main() {
     save_crash_files
     save_warmboot_files
 
+    if [[ "$asic" = "mellanox" ]]; then
+        collect_mellanox_dfw_dumps
+    fi
+
     finalize
 }