Hook execve() and the other exec*() functions.

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

diff --git a/src/trackfds.h b/src/trackfds.h
index e342b1223394e1a8fc9b4c28178ac44f478ddc3b..74d27aa4d4484fc08eaf97e9f05f0ed9481e1627 100644 (file)
--- a/src/trackfds.h
+++ b/src/trackfds.h
@@ -28,16 +28,40 @@ static size_t tracked_fds_count;
 static size_t tracked_fds_space;
 
 
+#ifdef DEBUG
+static void tracked_fds_debug(void) {
+    debug("    tracked_fds: %d/%d\t\t[%d]\n", tracked_fds_count,
+                                              tracked_fds_space,
+                                              getpid());
+    size_t i;
+    for (i = 0; i < tracked_fds_count; i++) {
+        debug("    tracked_fds[%d]: %d\n", i, tracked_fds[i]);
+    }
+}
+#endif
+
 /* 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,". */
 static void init_from_environment(void) {
+#ifdef DEBUG
+    debug("init_from_environment()\t\t[%d]\n", getpid());
+#endif
+    const char *env;
+
     initialized = 1;
     tracked_fds_count = 0;
 
-    const char *env = getenv(ENV_NAME_FDS);
+    /* 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);
+    if (env && env[0] != '\0') {
+        force_write_to_non_tty = 1;
+    }
+
+    env = getenv(ENV_NAME_FDS);
     if (!env) {
         return;
     }
@@ -91,20 +115,20 @@ static void init_from_environment(void) {
     tracked_fds_count = count;
 
     free(env_copy);
-}
 
-static void update_environment(void) {
-    /* An integer (32-bit) has at most 10 digits, + 1 for the comma after each
-     * number. Bigger file descriptors (which shouldn't occur in reality) are
-     * truncated. */
-    char env[tracked_fds_count * (10 + 1) * sizeof(char)];
-    char *x = env;
+#ifdef DEBUG
+    tracked_fds_debug();
+#endif
+}
 
+static void update_environment_buffer(char *x) {
     size_t i;
     for (i = 0; i < tracked_fds_count; i++) {
         int length = snprintf(x, 10 + 1, "%d", tracked_fds[i]);
-        if (length >= 10 + 1)
-            return;
+        if (length >= 10 + 1) {
+            /* Integer too big to fit the buffer, skip it. */
+            continue;
+        }
 
         /* Write comma after number. */
         x += length;
@@ -112,37 +136,60 @@ static void update_environment(void) {
         /* Make sure the string is always zero terminated. */
         *x = 0;
     }
+}
+inline static size_t update_environment_buffer_size(void) {
+    /* An integer (32-bit) has at most 10 digits, + 1 for the comma after each
+     * number. Bigger file descriptors (which shouldn't occur in reality) are
+     * skipped. */
+    return tracked_fds_count * (10 + 1) + 1 /* to fit '\0' */;
+}
+static void update_environment(void) {
+#ifdef DEBUG
+    debug("update_environment()\t\t[%d]\n", getpid());
+#endif
+
+    /* If we haven't parsed the environment we also haven't modified it - so
+     * nothing to do. */
+    if (!initialized) {
+        return;
+    }
+
+    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);
+#endif
 
     setenv(ENV_NAME_FDS, env, 1 /* overwrite */);
 }
 
 
-#ifdef DEBUG
-static void tracked_fds_debug(void) {
-    debug("tracked_fds: %d/%d\t[%d]\n", tracked_fds_count, tracked_fds_space,
-                                        getpid());
-    size_t i;
-    for (i = 0; i < tracked_fds_count; i++) {
-        debug("tracked_fds[%d]: %d\n", i, tracked_fds[i]);
-    }
-}
-#endif
 
 static void tracked_fds_add(int fd) {
     if (tracked_fds_count >= tracked_fds_space) {
         size_t new_space = tracked_fds_space + TRACKFDS_REALLOC_STEP;
-        if (!realloc(tracked_fds, sizeof(*tracked_fds) * new_space)) {
+        int *tmp = realloc(tracked_fds, sizeof(*tracked_fds) * new_space);
+        if (!tmp) {
             /* We can do nothing, just ignore the error. We made sure not to
              * destroy our state, so the new descriptor is ignored without any
              * other consequences. */
+#ifdef DEBUG
+            debug("realloc(tracked_fds, %zu) failed! [%d]\n",
+                  sizeof(*tracked_fds) * new_space, getpid());
+#endif
             return;
         }
+        tracked_fds = tmp;
         tracked_fds_space = new_space;
     }
 
     tracked_fds[tracked_fds_count++] = fd;
 
 #ifdef DEBUG
+    debug("tracked_fds_add(): %-3d\t\t[%d]\n", fd, getpid());
     tracked_fds_debug();
 #endif
 }
@@ -158,6 +205,7 @@ static int tracked_fds_remove(int fd) {
         tracked_fds_count--;
 
 #ifdef DEBUG
+        debug("tracked_fds_remove(): %-3d\t[%d]\n", fd, getpid());
         tracked_fds_debug();
 #endif