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127 lines
3.3 KiB
C
127 lines
3.3 KiB
C
/*
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* bin.c
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* Pastes handling.
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*
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* Copyright (c) 2022
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* Tom MTT. <tom@heimdall.pm>
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*
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* This file is licensed under the 3-Clause BSD License.
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* You should have received a copy of the 3-Clause BSD License
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* along with this program. If not, see
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* <https://basedwa.re/tmtt/feuille/src/branch/main/LICENSE>.
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*/
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#include "bin.h"
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#ifndef COSMOPOLITAN
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#include <errno.h> /* for errno */
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#include <stdio.h> /* for NULL, fclose, fopen, fputs, snprintf, FILE */
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#include <stdlib.h> /* for calloc, free, malloc, rand, realloc */
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#include <string.h> /* for strlen */
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#include <unistd.h> /* for access, F_OK */
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#endif
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#include "feuille.h" /* for Settings, settings */
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/* symbols used to generate IDs */
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static char *id_symbols = "abcdefghijklmnopqrstuvwxyz0123456789";
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/**
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* Generate a random ID, until one is available on disk.
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* min_length: the minimum ID length. Will be increased if a collision occurs.
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* -> a pointer to the ID. Needs to be freed.
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*/
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char *generate_id(int min_length)
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{
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int length = min_length;
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/* allocate a buffer to store the ID */
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char *buffer;
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if ((buffer = malloc((length + 1) * sizeof(char))) == NULL)
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return NULL;
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/* for each letter, generate a random one */
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for (int i = 0; i < length; i++) {
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if (i > 8 * min_length) {
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errno = EFBIG;
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free(buffer);
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return NULL;
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}
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buffer[i] = id_symbols[rand() % strlen(id_symbols)];
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buffer[i + 1] = 0;
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/* collision? */
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if (i == length - 1 && paste_exists(buffer)) {
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/* add one to the ID length and re-allocate the buffer */
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length++;
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void *tmp;
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if ((tmp = realloc(buffer, (length + 1) * sizeof(char))) == NULL) {
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free(buffer);
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return NULL;
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}
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buffer = tmp;
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}
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}
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return buffer;
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}
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/**
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* Check if an ID is already used.
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* id: the ID in question.
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* -> 1 if exists, 0 if not.
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*/
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int paste_exists(char *id)
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{
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return access(id, F_OK) == 0;
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}
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/**
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* Write the paste content to disk.
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* paste: the string containing the paste.
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* id: the ID of the paste.
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* -> 0 if done, -1 if not.
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*/
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int write_paste(char *paste, unsigned long paste_size, char *id)
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{
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/* open the file with write access */
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FILE *file;
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if ((file = fopen(id, "w")) == NULL)
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return -1;
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/* write the content to file */
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if (fwrite(paste, sizeof(char), paste_size, file) != paste_size) {
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fclose(file);
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return -1;
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}
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/* close the file (obviously) */
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fclose(file);
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return 0;
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}
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/**
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* Make the full URL for the paste.
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* id: the ID of the paste.
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* -> a pointer to the URL. Needs to be freed.
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*/
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char *create_url(char *id)
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{
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/* calculate the length of the URL */
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/* the 3 characters added are the trailing slash, newline and null byte */
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int length = strlen(id) + strlen(settings.url) + 3;
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/* allocate a buffer to store the URL */
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char *buffer;
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if ((buffer = malloc(length * sizeof(char))) == NULL)
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return NULL;
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/* set the buffer to the actual URL */
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snprintf(buffer, length, "%s/%s\n", settings.url, id);
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return buffer;
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}
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