init

3 files changed, 144 insertions, 0 deletions

diff --git a/LICENSE b/LICENSE
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+        DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE 
+                    Version 2, December 2004 
+
+ Copyright (C) 2004 Sam Hocevar <sam@hocevar.net> 
+
+ Everyone is permitted to copy and distribute verbatim or modified 
+ copies of this license document, and changing it is allowed as long 
+ as the name is changed. 
+
+            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE 
+   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION 
+
+  0. You just DO WHAT THE FUCK YOU WANT TO.
diff --git a/README.md b/README.md
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+# writed
+
+writed is a tiny daemon that displays messages received via the traditional `write`/`wall` mechanism as desktop notifications via `libnotify`.
+
+## building
+
+You'll need `libnotify`, `pkg-config`, and a C compiler.
+
+```
+gcc -std=c89 -lutil `pkg-config --cflags --libs libnotify` main.c -o writed
+```
+
+writed **must** be setgid `utmp`. `write` and `wall` only send messages to `pts` devices registered in `/var/run/utmp`, and without setgid `utmp`, writed will silently fail to receive messages.
+
+## usage
+
+Just run `writed` while you have a desktop notification daemon running.
diff --git a/main.c b/main.c
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+++ b/main.c
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+#define _XOPEN_SOURCE 600
+
+#include <ctype.h>
+#include <fcntl.h>
+#include <pwd.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <utmp.h>
+
+#include <libnotify/notify.h>
+
+char ut_line[UT_LINESIZE];
+
+static void handle_exit(int signal) {
+  notify_uninit();
+  logout(ut_line);
+}
+
+static void clean_string(char *str) {
+  char *src, *dest;
+  bool stripped_start = false;
+  bool should_increment = false;
+  for (src = dest = str; *src != '\0'; src++) {
+    *dest = *src;
+    if (isprint(*dest) && *dest != ' ' && *dest != '\n' && *dest != '\r') {
+      stripped_start = true;
+      should_increment = true;
+    }
+    if (*dest == ' ' && stripped_start) {
+      should_increment = true;
+    }
+    if (*dest == '\n' || *dest == '\r') {
+      stripped_start = false;
+    }
+    if (should_increment) {
+      should_increment = false;
+      dest++;
+    }
+  }
+  *dest = '\0';
+}
+
+int main(int argc, char **argv) {
+  char *name_ptr;
+  int master_fd, slave_fd;
+  char buffer[1024];
+  ssize_t bytes_read;
+  int uid;
+  struct utmp login_data;
+  struct passwd *pw_entry;
+  struct timeval current_time;
+  NotifyNotification *notification;
+
+  if ((master_fd = posix_openpt(O_RDWR)) < 0)
+    return 1;
+  if (grantpt(master_fd) < 0)
+    return 1;
+  if (unlockpt(master_fd) < 0)
+    return 1;
+  if ((name_ptr = ptsname(master_fd)) == NULL)
+    return 1;
+
+  if ((slave_fd = open(name_ptr, O_RDONLY)) < 0)
+    return 1;
+
+  memset(&login_data, 0, sizeof(login_data));
+
+  uid = getuid();
+  pw_entry = getpwuid(uid);
+  if (!pw_entry)
+    return 1;
+  strncpy(login_data.ut_name, pw_entry->pw_name, sizeof(login_data.ut_name));
+
+  if (!memcmp(name_ptr, "/dev/", 5))
+    name_ptr += 5;
+  strncpy(login_data.ut_line, name_ptr, sizeof(login_data.ut_line));
+  strncpy(ut_line, name_ptr, sizeof(ut_line));
+
+  notify_init("writed");
+
+  signal(SIGTERM, handle_exit);
+  signal(SIGINT, handle_exit);
+  signal(SIGHUP, handle_exit);
+
+  gettimeofday(&current_time, NULL);
+  memcpy(&login_data.ut_tv, &current_time, sizeof(login_data.ut_tv));
+
+  login_data.ut_type = USER_PROCESS;
+  login_data.ut_pid = getpid();
+  dup2(slave_fd, 0);
+  login(&login_data);
+
+  for (;;) {
+    bytes_read = read(master_fd, buffer, sizeof(buffer));
+    if (bytes_read < 0)
+      break;
+    else if (bytes_read > 0) {
+      buffer[sizeof(buffer) - 1] = '\x0';
+      clean_string(buffer);
+      notification = notify_notification_new("System Broadcast", buffer, 0);
+      notify_notification_show(notification, NULL);
+      g_object_unref(G_OBJECT(notification));
+    }
+  }
+
+  handle_exit(15);
+  return 0;
+}