From b950cdb79209e092d20d629bd1b0e9211647bd1e Mon Sep 17 00:00:00 2001
From: Simon Ruderich <simon@ruderich.org>
Date: Sun, 7 Jul 2013 13:33:44 +0200
Subject: [PATCH] Add COLORED_STDERR_IGNORED_BINARIES to exclude binaries.

---
 README                    | 12 ++++++++++
 src/constants.h           |  1 +
 src/trackfds.h            | 46 +++++++++++++++++++++++++++++++++++++++
 tests/lib.sh              |  1 +
 tests/test_environment.sh | 17 +++++++++++++++
 5 files changed, 77 insertions(+)

diff --git a/README b/README
index e9772b4..4827509 100644
--- a/README
+++ b/README
@@ -93,6 +93,10 @@ The following additional environment variables are available:
   If set to an non-empty value add pre/post strings even when not writing to a
   terminal, e.g. when writing to a file. By default, only writes to a terminal
   are colored.
+- 'COLORED_STDERR_IGNORED_BINARIES'
+  Comma separated list of binary names/paths which should not be tracked
+  (including their children). Useful for `reset` which writes to the terminal
+  but fails to work if the output is colored. See below for an example.
 
 All environment variables starting with 'COLORED_STDERR_PRIVATE_*' are
 internal variables used by the implementation and should not be set manually.
@@ -113,6 +117,12 @@ Bourne shell:
     COLORED_STDERR_POST="${esc}[0m" # default
     export COLORED_STDERR_PRE COLORED_STDERR_POST
 
+Fix `reset`; its writes to the terminal must be unaltered. `reset` is
+symbolic-link to `tset` on some systems, adapt as necessary:
+
+    COLORED_STDERR_IGNORED_BINARIES=/usr/bin/tset
+    export COLORED_STDERR_IGNORED_BINARIES
+
 
 DEBUG
 -----
@@ -143,6 +153,8 @@ KNOWN ISSUES
   (which might be redirected to stderr). Can't be fixed as the compiler
   inlines the code into the program without calling any function.
 - Test `test_stdio.sh` fails for this reason on FreeBSD.
+- 'COLORED_STDERR_IGNORED_BINARIES' requries the `/proc` file system.
+  Suggestions welcome.
 
 
 BUGS
diff --git a/src/constants.h b/src/constants.h
index 3e41261..45650ff 100644
--- a/src/constants.h
+++ b/src/constants.h
@@ -25,6 +25,7 @@
 #define ENV_NAME_PRE_STRING  "COLORED_STDERR_PRE"
 #define ENV_NAME_POST_STRING "COLORED_STDERR_POST"
 #define ENV_NAME_FORCE_WRITE "COLORED_STDERR_FORCE_WRITE"
+#define ENV_NAME_IGNORED_BINARIES "COLORED_STDERR_IGNORED_BINARIES"
 #define ENV_NAME_PRIVATE_FDS "COLORED_STDERR_PRIVATE_FDS"
 
 /* Strings written before/after each matched function. */
diff --git a/src/trackfds.h b/src/trackfds.h
index 5720b0c..28b38fb 100644
--- a/src/trackfds.h
+++ b/src/trackfds.h
@@ -50,6 +50,36 @@ static void tracked_fds_debug(void) {
 }
 #endif
 
+/* Check if filename occurs in the comma-separated list ignore. */
+static int is_program_ignored(char const *filename, char const *ignore) {
+    size_t length;
+    size_t filename_length = strlen(filename);
+
+#ifdef DEBUG
+    debug("  is_program_ignored(\"%s\", \"%s\")\n", filename, ignore);
+#endif
+
+    for (; *ignore; ignore += length) {
+        while (*ignore == ',') {
+            ignore++;
+        }
+
+        length = strcspn(ignore, ",");
+        if (length == 0) {
+            break;
+        }
+
+        if (length != filename_length) {
+            continue;
+        }
+        if (!strncmp(filename, ignore, length)) {
+            return 1;
+        }
+    }
+
+    return 0;
+}
+
 static int init_tracked_fds_list(size_t count) {
     assert(count > 0);
 
@@ -88,6 +118,22 @@ static void init_from_environment(void) {
     initialized = 1;
     tracked_fds_list_count = 0;
 
+    /* Don't color writes to stderr for this binary (and its children) if it's
+     * contained in the comma-separated list in ENV_NAME_IGNORED_BINARIES. */
+    env = getenv(ENV_NAME_IGNORED_BINARIES);
+    if (env) {
+        char path[512];
+
+        /* TODO: Don't require /proc/. */
+        ssize_t written = readlink("/proc/self/exe", path, sizeof(path) - 1);
+        if (written > 0) {
+            path[written] = 0; /* readlink() does not null-terminate! */
+            if (is_program_ignored(path, env)) {
+                return;
+            }
+        }
+    }
+
     /* If ENV_NAME_FORCE_WRITE is set and not empty, allow writes to a non-tty
      * device. Use with care! Mainly used for the test suite. */
     env = getenv(ENV_NAME_FORCE_WRITE);
diff --git a/tests/lib.sh b/tests/lib.sh
index 33a3721..7face08 100644
--- a/tests/lib.sh
+++ b/tests/lib.sh
@@ -20,6 +20,7 @@ set -e
 
 # Allow running the script directly without running `make check`.
 test "x$builddir" = x && builddir=.
+test "x$abs_builddir" = x && abs_builddir="`pwd`"
 test "x$EGREP" = x && EGREP='grep -E'
 
 # The tests fail if running under coloredstderr because the tests redirect
diff --git a/tests/test_environment.sh b/tests/test_environment.sh
index 47a02a2..d402472 100755
--- a/tests/test_environment.sh
+++ b/tests/test_environment.sh
@@ -59,3 +59,20 @@ COLORED_STDERR_FDS=
 export COLORED_STDERR_FDS
 test_program          example example_environment_empty
 test_program_subshell example example_environment_empty
+
+unset COLORED_STDERR_FDS
+
+
+# Test COLORED_STDERR_IGNORED_BINARIES.
+
+if test -x /proc/self/exe; then
+    COLORED_STDERR_IGNORED_BINARIES="$abs_builddir/example"
+    export COLORED_STDERR_IGNORED_BINARIES
+    test_program          example example_environment_empty
+    test_program_subshell example example_environment_empty
+
+    COLORED_STDERR_IGNORED_BINARIES=",some,other,path,,"
+    export COLORED_STDERR_IGNORED_BINARIES
+    test_program          example example_environment
+    test_program_subshell example example_environment
+fi
-- 
2.43.2