BIO: Add BIO_f_prefix(), a text line prefixing filter

Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/10531)

crypto/bio/bf_prefix.c

@@ -0,0 +1,207 @@
+/*
+ * Copyright 2018-2019 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include "bio_local.h"
+
+static int prefix_write(BIO *b, const char *out, size_t outl,
+                        size_t *numwritten);
+static int prefix_read(BIO *b, char *buf, size_t size, size_t *numread);
+static int prefix_puts(BIO *b, const char *str);
+static int prefix_gets(BIO *b, char *str, int size);
+static long prefix_ctrl(BIO *b, int cmd, long arg1, void *arg2);
+static int prefix_create(BIO *b);
+static int prefix_destroy(BIO *b);
+static long prefix_callback_ctrl(BIO *b, int cmd, BIO_info_cb *fp);
+
+static const BIO_METHOD prefix_meth = {
+    BIO_TYPE_BUFFER,
+    "prefix",
+    prefix_write,
+    NULL,
+    prefix_read,
+    NULL,
+    prefix_puts,
+    prefix_gets,
+    prefix_ctrl,
+    prefix_create,
+    prefix_destroy,
+    prefix_callback_ctrl,
+};
+
+const BIO_METHOD *BIO_f_prefix(void)
+{
+    return &prefix_meth;
+}
+
+typedef struct prefix_ctx_st {
+    char *prefix;              /* Text prefix, given by user */
+    unsigned int indent;       /* Indentation amount, given by user */
+
+    int linestart;             /* flag to indicate we're at the line start */
+} PREFIX_CTX;
+
+static int prefix_create(BIO *b)
+{
+    PREFIX_CTX *ctx = OPENSSL_zalloc(sizeof(*ctx));
+
+    if (ctx == NULL)
+        return 0;
+
+    ctx->prefix = NULL;
+    ctx->indent = 0;
+    ctx->linestart = 1;
+    BIO_set_data(b, ctx);
+    BIO_set_init(b, 1);
+    return 1;
+}
+
+static int prefix_destroy(BIO *b)
+{
+    PREFIX_CTX *ctx = BIO_get_data(b);
+
+    OPENSSL_free(ctx->prefix);
+    OPENSSL_free(ctx);
+    return 1;
+}
+
+static int prefix_read(BIO *b, char *in, size_t size, size_t *numread)
+{
+    return BIO_read_ex(BIO_next(b), in, size, numread);
+}
+
+static int prefix_write(BIO *b, const char *out, size_t outl,
+                        size_t *numwritten)
+{
+    PREFIX_CTX *ctx = BIO_get_data(b);
+
+    if (ctx == NULL)
+        return 0;
+
+    /*
+     * If no prefix is set or if it's empty, and no indentation amount is set,
+     * we've got nothing to do here
+     */
+    if ((ctx->prefix == NULL || *ctx->prefix == '\0')
+        && ctx->indent == 0) {
+        /*
+         * We do note if what comes next will be a new line, though, so we're
+         * prepared to handle prefix and indentation the next time around.
+         */
+        if (outl > 0)
+            ctx->linestart = (out[outl-1] == '\n');
+        return BIO_write_ex(BIO_next(b), out, outl, numwritten);
+    }
+
+    *numwritten = 0;
+
+    while (outl > 0) {
+        size_t i;
+        char c;
+
+        /*
+         * If we know that we're at the start of the line, output prefix and
+         * indentation.
+         */
+        if (ctx->linestart) {
+            size_t dontcare;
+
+            if (ctx->prefix != NULL
+                && !BIO_write_ex(BIO_next(b), ctx->prefix, strlen(ctx->prefix),
+                                 &dontcare))
+                return 0;
+            BIO_printf(BIO_next(b), "%*s", ctx->indent, "");
+            ctx->linestart = 0;
+        }
+
+        /* Now, go look for the next LF, or the end of the string */
+        for (i = 0, c = '\0'; i < outl && (c = out[i]) != '\n'; i++)
+            continue;
+        if (c == '\n')
+            i++;
+
+        /* Output what we found so far */
+        while (i > 0) {
+            size_t num = 0;
+
+            if (!BIO_write_ex(BIO_next(b), out, i, &num))
+                return 0;
+            out += num;
+            outl -= num;
+            *numwritten += num;
+            i -= num;
+        }
+
+        /* If we found a LF, what follows is a new line, so take note */
+        if (c == '\n')
+            ctx->linestart = 1;
+    }
+
+    return 1;
+}
+
+static long prefix_ctrl(BIO *b, int cmd, long num, void *ptr)
+{
+    long ret = 0;
+    PREFIX_CTX *ctx = BIO_get_data(b);
+
+    if (ctx == NULL)
+        return -1;
+
+    switch (cmd) {
+    case BIO_CTRL_SET_PREFIX:
+        OPENSSL_free(ctx->prefix);
+        if (ptr == NULL) {
+            ctx->prefix = NULL;
+            ret = 1;
+        } else {
+            ctx->prefix = OPENSSL_strdup((const char *)ptr);
+            ret = ctx->prefix != NULL;
+        }
+        break;
+    case BIO_CTRL_SET_INDENT:
+        if (num >= 0) {
+            ctx->indent = (unsigned int)num;
+            ret = 1;
+        }
+        break;
+    case BIO_CTRL_GET_INDENT:
+        ret = (long)ctx->indent;
+        break;
+    default:
+        /* Commands that we intercept before passing them along */
+        switch (cmd) {
+        case BIO_C_FILE_SEEK:
+        case BIO_CTRL_RESET:
+            ctx->linestart = 1;
+            break;
+        }
+        if (BIO_next(b) != NULL)
+            ret = BIO_ctrl(BIO_next(b), cmd, num, ptr);
+        break;
+    }
+    return ret;
+}
+
+static long prefix_callback_ctrl(BIO *b, int cmd, BIO_info_cb *fp)
+{
+    return BIO_callback_ctrl(BIO_next(b), cmd, fp);
+}
+
+static int prefix_gets(BIO *b, char *buf, int size)
+{
+    return BIO_gets(BIO_next(b), buf, size);
+}
+
+static int prefix_puts(BIO *b, const char *str)
+{
+    return BIO_write(b, str, strlen(str));
+}

crypto/bio/build.info

@@ -15,4 +15,4 @@ SOURCE[../../libcrypto]=\
 
 # Filters
 SOURCE[../../libcrypto]=\
-        bf_null.c bf_buff.c bf_lbuf.c bf_nbio.c
+        bf_null.c bf_buff.c bf_lbuf.c bf_nbio.c bf_prefix.c

doc/man3/BIO_f_prefix.pod

@@ -0,0 +1,70 @@
+=pod
+
+=head1 NAME
+
+BIO_f_prefix, BIO_set_prefix, BIO_set_indent, BIO_get_indent
+- prefix BIO filter
+
+=head1 SYNOPSIS
+
+ #include <openssl/bio.h>
+
+ const BIO_METHOD *BIO_f_prefix(void);
+ long BIO_set_prefix(BIO *b, const char *prefix);
+ long BIO_set_indent(BIO *b, long indent);
+ long BIO_get_indent(BIO *b);
+
+=head1 DESCRIPTION
+
+BIO_f_cipher() returns the prefix BIO method. This is a filter for
+text output, where each line gets automatically prefixed and indented
+according to user input.
+
+The prefix and the indentation are combined.  For each line of output
+going through this filter, the prefix is output first, then the amount
+of additional spaces indicated by the indentation, and then the line
+itself.
+
+By default, there is no prefix, and indentation is set to 0.
+
+BIO_set_prefix() sets the prefix to be used for future lines of
+text, using I<prefix>.  I<prefix> may be NULL, signifying that there
+should be no prefix.  If I<prefix> isn't NULL, this function makes a
+copy of it.
+
+BIO_set_indent() sets the indentation to be used for future lines of
+text, using I<indent>.  Negative values are not allowed.
+
+BIO_get_indent() gets the current indentation.
+
+=head1 NOTES
+
+BIO_set_prefix(), BIO_set_indent() and BIO_get_indent() are
+implemented as macros.
+
+=head1 RETURN VALUES
+
+BIO_f_prefix() returns the prefix BIO method.
+
+BIO_set_prefix() returns 1 if the prefix was correctly set, or 0 on
+failure.
+
+BIO_set_indent() returns 1 if the prefix was correctly set, or 0 on
+failure.
+
+BIO_get_indent() returns the current indentation.
+
+=head1 SEE ALSO
+
+L<bio(7)>
+
+=head1 COPYRIGHT
+
+Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
+
+Licensed under the Apache License 2.0 (the "License").  You may not use
+this file except in compliance with the License.  You can obtain a copy
+in the file LICENSE in the source distribution or at
+L<https://www.openssl.org/source/license.html>.
+
+=cut

include/openssl/bio.h

@@ -160,6 +160,11 @@ extern "C" {
 # define BIO_CTRL_DGRAM_SCTP_WAIT_FOR_DRY       77
 # define BIO_CTRL_DGRAM_SCTP_MSG_WAITING        78
 
+/* BIO_f_prefix controls */
+# define BIO_CTRL_SET_PREFIX                    79
+# define BIO_CTRL_SET_INDENT                    80
+# define BIO_CTRL_GET_INDENT                    81
+
 # ifndef OPENSSL_NO_KTLS
 #  define BIO_get_ktls_send(b)         \
      BIO_ctrl(b, BIO_CTRL_GET_KTLS_SEND, 0, NULL)
@@ -552,6 +557,11 @@ int BIO_ctrl_reset_read_request(BIO *b);
 # define BIO_dgram_get_mtu_overhead(b) \
          (unsigned int)BIO_ctrl((b), BIO_CTRL_DGRAM_GET_MTU_OVERHEAD, 0, NULL)
 
+/* ctrl macros for BIO_f_prefix */
+# define BIO_set_prefix(b,p) BIO_ctrl((b), BIO_CTRL_SET_PREFIX, 0, (void *)(p))
+# define BIO_set_indent(b,i) BIO_ctrl((b), BIO_CTRL_SET_INDENT, (i), NULL)
+# define BIO_get_indent(b) BIO_ctrl((b), BIO_CTRL_GET_INDENT, 0, NULL)
+
 #define BIO_get_ex_new_index(l, p, newf, dupf, freef) \
     CRYPTO_get_ex_new_index(CRYPTO_EX_INDEX_BIO, l, p, newf, dupf, freef)
 int BIO_set_ex_data(BIO *bio, int idx, void *data);
@@ -630,6 +640,7 @@ const BIO_METHOD *BIO_f_null(void);
 const BIO_METHOD *BIO_f_buffer(void);
 const BIO_METHOD *BIO_f_linebuffer(void);
 const BIO_METHOD *BIO_f_nbio_test(void);
+const BIO_METHOD *BIO_f_prefix(void);
 # ifndef OPENSSL_NO_DGRAM
 const BIO_METHOD *BIO_s_datagram(void);
 int BIO_dgram_non_fatal_error(int error);

util/libcrypto.num

@@ -4911,3 +4911,4 @@ i2d_X509_PUBKEY_bio                     ?	3_0_0	EXIST::FUNCTION:
 RSA_get0_pss_params                     ?	3_0_0	EXIST::FUNCTION:RSA
 X509_cmp_timeframe                      ?	3_0_0	EXIST::FUNCTION:
 OSSL_CMP_MSG_get0_header                ?	3_0_0	EXIST::FUNCTION:CMP
+BIO_f_prefix                            ?	3_0_0	EXIST::FUNCTION:

util/other.syms

@@ -127,6 +127,7 @@ BIO_get_conn_port                       define
 BIO_get_conn_ip_family                  define
 BIO_get_fd                              define
 BIO_get_fp                              define
+BIO_get_indent                          define
 BIO_get_info_callback                   define
 BIO_get_md                              define
 BIO_get_md_ctx                          define
@@ -158,12 +159,14 @@ BIO_set_conn_port                       define
 BIO_set_conn_ip_family                  define
 BIO_set_fd                              define
 BIO_set_fp                              define
+BIO_set_indent                          define
 BIO_set_info_callback                   define
 BIO_set_md                              define
 BIO_set_mem_buf                         define
 BIO_set_mem_eof_return                  define
 BIO_set_nbio                            define
 BIO_set_nbio_accept                     define
+BIO_set_prefix                          define
 BIO_set_read_buffer_size                define
 BIO_set_ssl                             define
 BIO_set_ssl_mode                        define