From aedbbec88aa0a9a38e588eabfbecb8058652002b Mon Sep 17 00:00:00 2001
From: Roman Chvanikov <chvanikoff@pm.me>
Date: Sat, 11 Jul 2020 15:48:45 +0300
Subject: [PATCH 1/6] Add Pleroma.Utils.command_available?/1 and use where
 appropriate

---
 lib/pleroma/upload/filter/exiftool.ex |  9 ++++++++-
 lib/pleroma/utils.ex                  | 15 +++++++++++++++
 mix.exs                               |  6 +++---
 test/upload/filter/exiftool_test.exs  |  2 ++
 4 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/lib/pleroma/upload/filter/exiftool.ex b/lib/pleroma/upload/filter/exiftool.ex
index c7fb6aefa..94622acd0 100644
--- a/lib/pleroma/upload/filter/exiftool.ex
+++ b/lib/pleroma/upload/filter/exiftool.ex
@@ -9,8 +9,15 @@ defmodule Pleroma.Upload.Filter.Exiftool do
   """
   @behaviour Pleroma.Upload.Filter
 
+  require Logger
+
   def filter(%Pleroma.Upload{tempfile: file, content_type: "image" <> _}) do
-    System.cmd("exiftool", ["-overwrite_original", "-gps:all=", file], parallelism: true)
+    if Pleroma.Utils.command_available?("exiftool") do
+      System.cmd("exiftool", ["-overwrite_original", "-gps:all=", file], parallelism: true)
+    else
+      Logger.warn("exiftool is not available, filter #{__MODULE__} skipped")
+    end
+
     :ok
   end
 
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
diff --git a/mix.exs b/mix.exs
index d7992ee37..5cd06e8fd 100644
--- a/mix.exs
+++ b/mix.exs
@@ -234,10 +234,10 @@ defmodule Pleroma.Mixfile do
   defp version(version) do
     identifier_filter = ~r/[^0-9a-z\-]+/i
 
-    {_cmdgit, cmdgit_err} = System.cmd("sh", ["-c", "command -v git"])
+    git_available? = Pleroma.Utils.command_available?("git")
 
     git_pre_release =
-      if cmdgit_err == 0 do
+      if git_available? do
         {tag, tag_err} =
           System.cmd("git", ["describe", "--tags", "--abbrev=0"], stderr_to_stdout: true)
 
@@ -263,7 +263,7 @@ defmodule Pleroma.Mixfile do
 
     # Branch name as pre-release version component, denoted with a dot
     branch_name =
-      with 0 <- cmdgit_err,
+      with true <- git_available?,
            {branch_name, 0} <- System.cmd("git", ["rev-parse", "--abbrev-ref", "HEAD"]),
            branch_name <- String.trim(branch_name),
            branch_name <- System.get_env("PLEROMA_BUILD_BRANCH") || branch_name,
diff --git a/test/upload/filter/exiftool_test.exs b/test/upload/filter/exiftool_test.exs
index a1b7e46cd..8ed7d650b 100644
--- a/test/upload/filter/exiftool_test.exs
+++ b/test/upload/filter/exiftool_test.exs
@@ -7,6 +7,8 @@ defmodule Pleroma.Upload.Filter.ExiftoolTest do
   alias Pleroma.Upload.Filter
 
   test "apply exiftool filter" do
+    assert Pleroma.Utils.command_available?("exiftool")
+
     File.cp!(
       "test/fixtures/DSCN0010.jpg",
       "test/fixtures/DSCN0010_tmp.jpg"

From 05187d497da1844005eaf96fbcab65840a578bb1 Mon Sep 17 00:00:00 2001
From: Roman Chvanikov <chvanikoff@pm.me>
Date: Sat, 11 Jul 2020 16:09:46 +0300
Subject: [PATCH 2/6] One can not simply call application modules from mix.exs

---
 mix.exs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mix.exs b/mix.exs
index 5cd06e8fd..a775e54a4 100644
--- a/mix.exs
+++ b/mix.exs
@@ -234,7 +234,7 @@ defmodule Pleroma.Mixfile do
   defp version(version) do
     identifier_filter = ~r/[^0-9a-z\-]+/i
 
-    git_available? = Pleroma.Utils.command_available?("git")
+    git_available? = match?({_output, 0}, System.cmd("sh", ["-c", "command -v git"]))
 
     git_pre_release =
       if git_available? do

From 45bd64e2a7a08377e260e93c8e1744166bfc133a Mon Sep 17 00:00:00 2001
From: Roman Chvanikov <chvanikoff@pm.me>
Date: Sat, 11 Jul 2020 18:11:23 +0300
Subject: [PATCH 3/6] Error in Filter.Exiftool if exiftool not found

---
 lib/pleroma/upload/filter/exiftool.ex | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/lib/pleroma/upload/filter/exiftool.ex b/lib/pleroma/upload/filter/exiftool.ex
index 94622acd0..6a40e152f 100644
--- a/lib/pleroma/upload/filter/exiftool.ex
+++ b/lib/pleroma/upload/filter/exiftool.ex
@@ -14,11 +14,10 @@ defmodule Pleroma.Upload.Filter.Exiftool do
   def filter(%Pleroma.Upload{tempfile: file, content_type: "image" <> _}) do
     if Pleroma.Utils.command_available?("exiftool") do
       System.cmd("exiftool", ["-overwrite_original", "-gps:all=", file], parallelism: true)
+      :ok
     else
-      Logger.warn("exiftool is not available, filter #{__MODULE__} skipped")
+      {:error, "exiftool command not found"}
     end
-
-    :ok
   end
 
   def filter(_), do: :ok

From 523f1b93a48d88ef8aa04ca17d51d1d0916b6093 Mon Sep 17 00:00:00 2001
From: Roman Chvanikov <chvanikoff@pm.me>
Date: Sat, 11 Jul 2020 18:15:51 +0300
Subject: [PATCH 4/6] Remove Logger requirement

---
 lib/pleroma/upload/filter/exiftool.ex | 2 --
 1 file changed, 2 deletions(-)

diff --git a/lib/pleroma/upload/filter/exiftool.ex b/lib/pleroma/upload/filter/exiftool.ex
index 6a40e152f..e1b976c98 100644
--- a/lib/pleroma/upload/filter/exiftool.ex
+++ b/lib/pleroma/upload/filter/exiftool.ex
@@ -9,8 +9,6 @@ defmodule Pleroma.Upload.Filter.Exiftool do
   """
   @behaviour Pleroma.Upload.Filter
 
-  require Logger
-
   def filter(%Pleroma.Upload{tempfile: file, content_type: "image" <> _}) do
     if Pleroma.Utils.command_available?("exiftool") do
       System.cmd("exiftool", ["-overwrite_original", "-gps:all=", file], parallelism: true)

From 3116a75e80144dff79232c8676bd28ed285a14d9 Mon Sep 17 00:00:00 2001
From: Roman Chvanikov <chvanikoff@pm.me>
Date: Sat, 11 Jul 2020 18:22:03 +0300
Subject: [PATCH 5/6] Check if mogrify available before calling it

---
 lib/pleroma/upload/filter/mogrifun.ex |  9 ++++++---
 lib/pleroma/upload/filter/mogrify.ex  | 10 +++++++---
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/lib/pleroma/upload/filter/mogrifun.ex b/lib/pleroma/upload/filter/mogrifun.ex
index 7d95577a4..8f362333d 100644
--- a/lib/pleroma/upload/filter/mogrifun.ex
+++ b/lib/pleroma/upload/filter/mogrifun.ex
@@ -35,9 +35,12 @@ defmodule Pleroma.Upload.Filter.Mogrifun do
   ]
 
   def filter(%Pleroma.Upload{tempfile: file, content_type: "image" <> _}) do
-    Filter.Mogrify.do_filter(file, [Enum.random(@filters)])
-
-    :ok
+    if Pleroma.Utils.command_available?("mogrify") do
+      Filter.Mogrify.do_filter(file, [Enum.random(@filters)])
+      :ok
+    else
+      {: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..4bd0c2eb4 100644
--- a/lib/pleroma/upload/filter/mogrify.ex
+++ b/lib/pleroma/upload/filter/mogrify.ex
@@ -9,10 +9,14 @@ defmodule Pleroma.Upload.Filter.Mogrify do
   @type conversions :: conversion() | [conversion()]
 
   def filter(%Pleroma.Upload{tempfile: file, content_type: "image" <> _}) do
-    filters = Pleroma.Config.get!([__MODULE__, :args])
+    if Pleroma.Utils.command_available?("mogrify") do
+      filters = Pleroma.Config.get!([__MODULE__, :args])
 
-    do_filter(file, filters)
-    :ok
+      do_filter(file, filters)
+      :ok
+    else
+      {:error, "mogrify command not found"}
+    end
   end
 
   def filter(_), do: :ok

From 7569f225f1d43c6435eda6b62fd5eff3cd3408e0 Mon Sep 17 00:00:00 2001
From: Roman Chvanikov <chvanikoff@pm.me>
Date: Wed, 5 Aug 2020 19:38:55 +0300
Subject: [PATCH 6/6] Move checks to application startup

---
 lib/pleroma/application.ex            | 18 ++++++++++++++++++
 lib/pleroma/upload/filter/exiftool.ex | 14 +++++++++-----
 lib/pleroma/upload/filter/mogrifun.ex |  8 +++++---
 lib/pleroma/upload/filter/mogrify.ex  | 12 ++++++------
 4 files changed, 38 insertions(+), 14 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 e1b976c98..ea8798fe3 100644
--- a/lib/pleroma/upload/filter/exiftool.ex
+++ b/lib/pleroma/upload/filter/exiftool.ex
@@ -9,12 +9,16 @@ 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
-    if Pleroma.Utils.command_available?("exiftool") do
-      System.cmd("exiftool", ["-overwrite_original", "-gps:all=", file], parallelism: true)
-      :ok
-    else
-      {:error, "exiftool command not found"}
+    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
 
diff --git a/lib/pleroma/upload/filter/mogrifun.ex b/lib/pleroma/upload/filter/mogrifun.ex
index 8f362333d..a8503ac24 100644
--- a/lib/pleroma/upload/filter/mogrifun.ex
+++ b/lib/pleroma/upload/filter/mogrifun.ex
@@ -34,12 +34,14 @@ 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
-    if Pleroma.Utils.command_available?("mogrify") do
+    try do
       Filter.Mogrify.do_filter(file, [Enum.random(@filters)])
       :ok
-    else
-      {:error, "mogrify command not found"}
+    rescue
+      _e in ErlangError ->
+        {:error, "mogrify command not found"}
     end
   end
 
diff --git a/lib/pleroma/upload/filter/mogrify.ex b/lib/pleroma/upload/filter/mogrify.ex
index 4bd0c2eb4..7a45add5a 100644
--- a/lib/pleroma/upload/filter/mogrify.ex
+++ b/lib/pleroma/upload/filter/mogrify.ex
@@ -8,14 +8,14 @@ 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
-    if Pleroma.Utils.command_available?("mogrify") do
-      filters = Pleroma.Config.get!([__MODULE__, :args])
-
-      do_filter(file, filters)
+    try do
+      do_filter(file, Pleroma.Config.get!([__MODULE__, :args]))
       :ok
-    else
-      {:error, "mogrify command not found"}
+    rescue
+      _e in ErlangError ->
+        {:error, "mogrify command not found"}
     end
   end