update copyright year

[coloredstderr/coloredstderr.git] / src / trackfds.h

diff --git a/src/trackfds.h b/src/trackfds.h
index acf7ce336d18dd30d29a661d62fe9bdfbeba917c..c749f5e1d6f6cf142e5ce455888fb6d75c7eea58 100644 (file)
--- a/src/trackfds.h
+++ b/src/trackfds.h
@@ -1,7 +1,7 @@
 /*
  * Utility functions to track file descriptors.
  *
- * Copyright (C) 2013  Simon Ruderich
+ * Copyright (C) 2013-2015  Simon Ruderich
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -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);
 
@@ -69,11 +99,14 @@ static int init_tracked_fds_list(size_t count) {
     return 1;
 }
 
-/* Load tracked file descriptors from the environment. The environment is used
+/*
+ * Load tracked file descriptors from the environment. The environment is used
  * to pass the information to child processes.
  *
- * ENV_NAME_FDS has the following format: Each descriptor as string followed
- * by a comma; there's a trailing comma. Example: "2,4,". */
+ * ENV_NAME_FDS and ENV_NAME_PRIVATE_FDS have the following format: Each
+ * descriptor as string followed by a comma; there's a trailing comma.
+ * Example: "2,4,".
+ */
 static void init_from_environment(void) {
 #ifdef DEBUG
     debug("init_from_environment()\t\t[%d]\n", getpid());
@@ -82,9 +115,27 @@ static void init_from_environment(void) {
 
     int saved_errno = errno;
 
+    assert(!initialized);
+
     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);
@@ -92,14 +143,23 @@ static void init_from_environment(void) {
         force_write_to_non_tty = 1;
     }
 
+    /* Prefer user defined list of file descriptors, fall back to file
+     * descriptors passed through the environment from the parent process. */
     env = getenv(ENV_NAME_FDS);
+    if (env) {
+        used_fds_set_by_user = 1;
+    } else {
+        env = getenv(ENV_NAME_PRIVATE_FDS);
+    }
     if (!env) {
         errno = saved_errno;
         return;
     }
 #ifdef DEBUG
     debug("  getenv(\"%s\"): \"%s\"\n", ENV_NAME_FDS, env);
+    debug("  getenv(\"%s\"): \"%s\"\n", ENV_NAME_PRIVATE_FDS, env);
 #endif
+
     /* Environment must be treated read-only. */
     char env_copy[strlen(env) + 1];
     strcpy(env_copy, env);
@@ -127,10 +187,6 @@ static void init_from_environment(void) {
             goto next;
         }
 
-        if (i == count) {
-            break;
-        }
-
         /* Replace ',' to null-terminate number for atoi(). */
         *x = 0;
 
@@ -225,16 +281,29 @@ static void update_environment(void) {
         return;
     }
 
+    int saved_errno = errno;
+
     char env[update_environment_buffer_size()];
     env[0] = 0;
 
     update_environment_buffer(env);
 
 #if 0
-    debug("    setenv(\"%s\", \"%s\", 1)\n", ENV_NAME_FDS, env);
+    debug("    setenv(\"%s\", \"%s\", 1)\n", ENV_NAME_PRIVATE_FDS, env);
 #endif
+    setenv(ENV_NAME_PRIVATE_FDS, env, 1 /* overwrite */);
 
-    setenv(ENV_NAME_FDS, env, 1 /* overwrite */);
+    /* Child processes must use ENV_NAME_PRIVATE_FDS to get the updated list
+     * of tracked file descriptors, not the static list provided by the user
+     * in ENV_NAME_FDS.
+     *
+     * But only remove it if the static list in ENV_NAME_FDS was loaded by
+     * init_from_environment() and merged into ENV_NAME_PRIVATE_FDS. */
+    if (used_fds_set_by_user) {
+        unsetenv(ENV_NAME_FDS);
+    }
+
+    errno = saved_errno;
 }
 
 
@@ -329,9 +398,13 @@ static int tracked_fds_find_slow(int fd) noinline;
  */
 inline static int tracked_fds_find(int fd) always_inline;
 inline static int tracked_fds_find(int fd) {
-    assert(fd >= 0);
+    /* Invalid file descriptor. No assert() as we're called from the hooked
+     * macro. */
+    if (unlikely(fd < 0)) {
+        return 0;
+    }
 
-    if (fd < TRACKFDS_STATIC_COUNT) {
+    if (likely(fd < TRACKFDS_STATIC_COUNT)) {
         return tracked_fds[fd];
     }
 
@@ -339,6 +412,7 @@ inline static int tracked_fds_find(int fd) {
 }
 static int tracked_fds_find_slow(int fd) {
     assert(initialized);
+    assert(fd >= 0);
 
     if (tracked_fds_list_count == 0) {
         return 0;