upload kissy code

kissy.c

@@ -0,0 +1,94 @@
+/* KISSY (KISSY Interface for Sapphic Smooching over ttY) v1.0 by Magdalunaa
+
+This file needs to:
+- be owned by the tty group (or whatever group owns the terminal devices in your system)
+- have setgid set
+- be group executable
+- not be world writeable
+
+You can probably just use 2755 permissions. those work
+
+*/
+
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <dirent.h>
+#include <string.h>
+#include <pwd.h>
+
+// mreowww meow nya :3
+
+int main (int argc, char **argv) {
+    // are we running with setgid?
+    struct stat stat_self;
+    stat("/proc/self/exe", &stat_self);
+
+    if (!(stat_self.st_mode & S_ISGID && !(stat_self.st_mode & S_IWOTH))) {
+        printf("%s\n", "setgid is not set, or this file is world writeable.");
+        return 3;
+    }
+
+    // check we have at least one argument
+    if (argc < 2) {
+        printf("%s\n", "Not enough arguments!\nUsage: kissy [target] <message>");
+        return 0;
+    }
+
+    // try to find the target's uid
+    struct passwd *pw = getpwnam(argv[1]);
+    if (pw == NULL) {
+        printf("%s\n", "Cannot find target");
+        return 1;
+    }
+    int target = pw->pw_uid;
+
+    // get current username
+    struct passwd *pw2 = getpwuid(getuid());
+    if (pw == NULL) {
+        printf("%s\n", "Cannot find user");
+        return 2;
+    }
+    char* user = pw2->pw_name;
+
+    // if we have a second argument, set a custom kiss message
+    char* kiss;
+    if (argc >= 3)
+        kiss = argv[2];
+    else
+        kiss = "*mwah*";
+
+    short kissed = 0;
+    // iterate over all files in directory
+    DIR *dir = opendir("/dev/pts");
+    while (1) {
+        struct dirent *ent = readdir (dir);
+        if (ent == NULL)
+            break;
+        
+        char filepath[strlen("/dev/pts/") + strlen(ent->d_name) + 1];
+        strcpy(filepath, "/dev/pts/");
+        strcat(filepath, ent->d_name);
+
+        struct stat stats;
+        stat (filepath, &stats);
+
+        // find all terminals with the correct user and that are group-writable
+        if (stats.st_mode & S_IWGRP && stats.st_uid == target) {
+            kissed = 1;
+
+            if (stats.st_gid != getegid()) { // are we running as the tty user?
+                printf("%s\n", "Mismatch between file owner group and current effective group. Make sure this program is running with setgid.");
+            } else {
+                FILE *tty = fopen(filepath, "a"); // write to terminal!
+                fprintf(tty, "\n%s\n--%s\n", kiss, user);
+                fclose(tty);
+            }
+        }
+    }
+
+    // print a message if a suitable terminal couldn't be found
+    if (!kissed)
+            printf("%s\n", "Couldn't find any suitable terminals. User is not logged in or has not enabled messages.");
+}