5 files changed, 59 insertions, 9 deletions
diff --git a/lib/pleroma/application.ex b/lib/pleroma/application.ex
index 0ffb55358..c0b5db9f1 100644
--- a/lib/pleroma/application.ex
+++ b/lib/pleroma/application.ex
@@ -47,6 +47,7 @@ defmodule Pleroma.Application do
     Pleroma.ApplicationRequirements.verify!()
     setup_instrumenters()
     load_custom_modules()
+    check_system_commands()
     Pleroma.Docs.JSON.compile()
 
     adapter = Application.get_env(:tesla, :adapter)
@@ -249,4 +250,21 @@ defmodule Pleroma.Application do
   end
 
   defp http_children(_, _), do: []
+
+  defp check_system_commands do
+    filters = Config.get([Pleroma.Upload, :filters])
+
+    check_filter = fn filter, command_required ->
+      with true <- filter in filters,
+           false <- Pleroma.Utils.command_available?(command_required) do
+        Logger.error(
+          "#{filter} is specified in list of Pleroma.Upload filters, but the #{command_required} command is not found"
+        )
+      end
+    end
+
+    check_filter.(Pleroma.Upload.Filters.Exiftool, "exiftool")
+    check_filter.(Pleroma.Upload.Filters.Mogrify, "mogrify")
+    check_filter.(Pleroma.Upload.Filters.Mogrifun, "mogrify")
+  end
 end
diff --git a/lib/pleroma/upload/filter/exiftool.ex b/lib/pleroma/upload/filter/exiftool.ex
index c7fb6aefa..ea8798fe3 100644
--- a/lib/pleroma/upload/filter/exiftool.ex
+++ b/lib/pleroma/upload/filter/exiftool.ex
@@ -9,9 +9,17 @@ defmodule Pleroma.Upload.Filter.Exiftool do
   """
   @behaviour Pleroma.Upload.Filter
 
+  @spec filter(Pleroma.Upload.t()) :: :ok | {:error, String.t()}
   def filter(%Pleroma.Upload{tempfile: file, content_type: "image" <> _}) do
-    System.cmd("exiftool", ["-overwrite_original", "-gps:all=", file], parallelism: true)
-    :ok
+    try do
+      case System.cmd("exiftool", ["-overwrite_original", "-gps:all=", file], parallelism: true) do
+        {_response, 0} -> :ok
+        {error, 1} -> {:error, error}
+      end
+    rescue
+      _e in ErlangError ->
+        {:error, "exiftool command not found"}
+    end
   end
 
   def filter(_), do: :ok
diff --git a/lib/pleroma/upload/filter/mogrifun.ex b/lib/pleroma/upload/filter/mogrifun.ex
index 7d95577a4..a8503ac24 100644
--- a/lib/pleroma/upload/filter/mogrifun.ex
+++ b/lib/pleroma/upload/filter/mogrifun.ex
@@ -34,10 +34,15 @@ defmodule Pleroma.Upload.Filter.Mogrifun do
     [{"fill", "yellow"}, {"tint", "40"}]
   ]
 
+  @spec filter(Pleroma.Upload.t()) :: :ok | {:error, String.t()}
   def filter(%Pleroma.Upload{tempfile: file, content_type: "image" <> _}) do
-    Filter.Mogrify.do_filter(file, [Enum.random(@filters)])
-
-    :ok
+    try do
+      Filter.Mogrify.do_filter(file, [Enum.random(@filters)])
+      :ok
+    rescue
+      _e in ErlangError ->
+        {:error, "mogrify command not found"}
+    end
   end
 
   def filter(_), do: :ok
diff --git a/lib/pleroma/upload/filter/mogrify.ex b/lib/pleroma/upload/filter/mogrify.ex
index 2eb758006..7a45add5a 100644
--- a/lib/pleroma/upload/filter/mogrify.ex
+++ b/lib/pleroma/upload/filter/mogrify.ex
@@ -8,11 +8,15 @@ defmodule Pleroma.Upload.Filter.Mogrify do
   @type conversion :: action :: String.t() | {action :: String.t(), opts :: String.t()}
   @type conversions :: conversion() | [conversion()]
 
+  @spec filter(Pleroma.Upload.t()) :: :ok | {:error, String.t()}
   def filter(%Pleroma.Upload{tempfile: file, content_type: "image" <> _}) do
-    filters = Pleroma.Config.get!([__MODULE__, :args])
-
-    do_filter(file, filters)
-    :ok
+    try do
+      do_filter(file, Pleroma.Config.get!([__MODULE__, :args]))
+      :ok
+    rescue
+      _e in ErlangError ->
+        {:error, "mogrify command not found"}
+    end
   end
 
   def filter(_), do: :ok
diff --git a/lib/pleroma/utils.ex b/lib/pleroma/utils.ex
index 6b8e3accf..21d1159be 100644
--- a/lib/pleroma/utils.ex
+++ b/lib/pleroma/utils.ex
@@ -9,4 +9,19 @@ defmodule Pleroma.Utils do
     |> Enum.map(&Path.join(dir, &1))
     |> Kernel.ParallelCompiler.compile()
   end
+
+  @doc """
+  POSIX-compliant check if command is available in the system
+
+  ## Examples
+      iex> command_available?("git")
+      true
+      iex> command_available?("wrongcmd")
+      false
+
+  """
+  @spec command_available?(String.t()) :: boolean()
+  def command_available?(command) do
+    match?({_output, 0}, System.cmd("sh", ["-c", "command -v #{command}"]))
+  end
 end