apps/lib/bf_prefix.c

   1 /*
   2  * Copyright 2018 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 #include <stdio.h>
  11 #include <string.h>
  12 #include <errno.h>
  13 #include <openssl/bio.h>
  14 #include "apps.h"
  15
  16 static int prefix_write(BIO *b, const char *out, size_t outl,
  17                         size_t *numwritten);
  18 static int prefix_read(BIO *b, char *buf, size_t size, size_t *numread);
  19 static int prefix_puts(BIO *b, const char *str);
  20 static int prefix_gets(BIO *b, char *str, int size);
  21 static long prefix_ctrl(BIO *b, int cmd, long arg1, void *arg2);
  22 static int prefix_create(BIO *b);
  23 static int prefix_destroy(BIO *b);
  24 static long prefix_callback_ctrl(BIO *b, int cmd, BIO_info_cb *fp);
  25
  26 static BIO_METHOD *prefix_meth = NULL;
  27
  28 BIO_METHOD *apps_bf_prefix(void)
  29 {
  30     if (prefix_meth == NULL) {
  31         if ((prefix_meth =
  32              BIO_meth_new(BIO_TYPE_FILTER, "Prefix filter")) == NULL
  33             || !BIO_meth_set_create(prefix_meth, prefix_create)
  34             || !BIO_meth_set_destroy(prefix_meth, prefix_destroy)
  35             || !BIO_meth_set_write_ex(prefix_meth, prefix_write)
  36             || !BIO_meth_set_read_ex(prefix_meth, prefix_read)
  37             || !BIO_meth_set_puts(prefix_meth, prefix_puts)
  38             || !BIO_meth_set_gets(prefix_meth, prefix_gets)
  39             || !BIO_meth_set_ctrl(prefix_meth, prefix_ctrl)
  40             || !BIO_meth_set_callback_ctrl(prefix_meth, prefix_callback_ctrl)) {
  41             BIO_meth_free(prefix_meth);
  42             prefix_meth = NULL;
  43         }
  44     }
  45     return prefix_meth;
  46 }
  47
  48 typedef struct prefix_ctx_st {
  49     char *prefix;
  50     int linestart;               /* flag to indicate we're at the line start */
  51 } PREFIX_CTX;
  52
  53 static int prefix_create(BIO *b)
  54 {
  55     PREFIX_CTX *ctx = OPENSSL_zalloc(sizeof(*ctx));
  56
  57     if (ctx == NULL)
  58         return 0;
  59
  60     ctx->prefix = NULL;
  61     ctx->linestart = 1;
  62     BIO_set_data(b, ctx);
  63     BIO_set_init(b, 1);
  64     return 1;
  65 }
  66
  67 static int prefix_destroy(BIO *b)
  68 {
  69     PREFIX_CTX *ctx = BIO_get_data(b);
  70
  71     OPENSSL_free(ctx->prefix);
  72     OPENSSL_free(ctx);
  73     return 1;
  74 }
  75
  76 static int prefix_read(BIO *b, char *in, size_t size, size_t *numread)
  77 {
  78     return BIO_read_ex(BIO_next(b), in, size, numread);
  79 }
  80
  81 static int prefix_write(BIO *b, const char *out, size_t outl,
  82                         size_t *numwritten)
  83 {
  84     PREFIX_CTX *ctx = BIO_get_data(b);
  85
  86     if (ctx == NULL)
  87         return 0;
  88
  89     /* If no prefix is set or if it's empty, we've got nothing to do here */
  90     if (ctx->prefix == NULL || *ctx->prefix == '\0') {
  91         /* We do note if what comes next will be a new line, though */
  92         if (outl > 0)
  93             ctx->linestart = (out[outl-1] == '\n');
  94         return BIO_write_ex(BIO_next(b), out, outl, numwritten);
  95     }
  96
  97     *numwritten = 0;
  98
  99     while (outl > 0) {
 100         size_t i;
 101         char c;
 102
 103         /* If we know that we're at the start of the line, output the prefix */
 104         if (ctx->linestart) {
 105             size_t dontcare;
 106
 107             if (!BIO_write_ex(BIO_next(b), ctx->prefix, strlen(ctx->prefix),
 108                               &dontcare))
 109                 return 0;
 110             ctx->linestart = 0;
 111         }
 112
 113         /* Now, go look for the next LF, or the end of the string */
 114         for (i = 0, c = '\0'; i < outl && (c = out[i]) != '\n'; i++)
 115             continue;
 116         if (c == '\n')
 117             i++;
 118
 119         /* Output what we found so far */
 120         while (i > 0) {
 121             size_t num = 0;
 122
 123             if (!BIO_write_ex(BIO_next(b), out, i, &num))
 124                 return 0;
 125             out += num;
 126             outl -= num;
 127             *numwritten += num;
 128             i -= num;
 129         }
 130
 131         /* If we found a LF, what follows is a new line, so take note */
 132         if (c == '\n')
 133             ctx->linestart = 1;
 134     }
 135
 136     return 1;
 137 }
 138
 139 static long prefix_ctrl(BIO *b, int cmd, long num, void *ptr)
 140 {
 141     long ret = 0;
 142
 143     switch (cmd) {
 144     case PREFIX_CTRL_SET_PREFIX:
 145         {
 146             PREFIX_CTX *ctx = BIO_get_data(b);
 147
 148             if (ctx == NULL)
 149                 break;
 150
 151             OPENSSL_free(ctx->prefix);
 152             ctx->prefix = OPENSSL_strdup((const char *)ptr);
 153             ret = ctx->prefix != NULL;
 154         }
 155         break;
 156     default:
 157         if (BIO_next(b) != NULL)
 158             ret = BIO_ctrl(BIO_next(b), cmd, num, ptr);
 159         break;
 160     }
 161     return ret;
 162 }
 163
 164 static long prefix_callback_ctrl(BIO *b, int cmd, BIO_info_cb *fp)
 165 {
 166     return BIO_callback_ctrl(BIO_next(b), cmd, fp);
 167 }
 168
 169 static int prefix_gets(BIO *b, char *buf, int size)
 170 {
 171     return BIO_gets(BIO_next(b), buf, size);
 172 }
 173
 174 static int prefix_puts(BIO *b, const char *str)
 175 {
 176     return BIO_write(b, str, strlen(str));
 177 }