xml_io.c

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/*
 * Copyright 2004-2024 the Pacemaker project contributors
 *
 * The version control history for this file may have further details.
 *
 * This source code is licensed under the GNU Lesser General Public License
 * version 2.1 or later (LGPLv2.1+) WITHOUT ANY WARRANTY.
 */

#include <crm_internal.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>

#include <bzlib.h>
#include <libxml/parser.h>
#include <libxml/tree.h>
#include <libxml/xmlIO.h>               // xmlOutputBuffer*

#include <crm/crm.h>
#include <crm/common/xml.h>
#include <crm/common/xml_io.h>
#include "crmcommon_private.h"

/* @COMPAT XML_PARSE_RECOVER allows some XML errors to be silently worked around
 * by libxml2, which is potentially ambiguous and dangerous. We should drop it
 * when we can break backward compatibility with configurations that might be
 * relying on it (i.e. pacemaker 3.0.0).
 */
#define PCMK__XML_PARSE_OPTS_WITHOUT_RECOVER    (XML_PARSE_NOBLANKS)
#define PCMK__XML_PARSE_OPTS_WITH_RECOVER       (XML_PARSE_NOBLANKS \
                                                 |XML_PARSE_RECOVER)

static char *
read_stdin(void)
{
    char *buf = NULL;
    size_t length = 0;

    do {
        buf = pcmk__realloc(buf, length + PCMK__BUFFER_SIZE + 1);
        length += fread(buf + length, 1, PCMK__BUFFER_SIZE, stdin);
    } while ((feof(stdin) == 0) && (ferror(stdin) == 0));

    if (ferror(stdin) != 0) {
        crm_err("Error reading input from stdin");
        free(buf);
        buf = NULL;
    } else {
        buf[length] = '\0';
    }
    clearerr(stdin);
    return buf;
}

static char *
decompress_file(const char *filename)
{
    char *buffer = NULL;
    int rc = pcmk_rc_ok;
    size_t length = 0;
    BZFILE *bz_file = NULL;
    FILE *input = fopen(filename, "r");

    if (input == NULL) {
        crm_perror(LOG_ERR, "Could not open %s for reading", filename);
        return NULL;
    }

    bz_file = BZ2_bzReadOpen(&rc, input, 0, 0, NULL, 0);
    rc = pcmk__bzlib2rc(rc);
    if (rc != pcmk_rc_ok) {
        crm_err("Could not prepare to read compressed %s: %s "
                CRM_XS " rc=%d", filename, pcmk_rc_str(rc), rc);
        goto done;
    }

    // cppcheck seems not to understand the abort-logic in pcmk__realloc
    // cppcheck-suppress memleak
    do {
        int read_len = 0;

        buffer = pcmk__realloc(buffer, length + PCMK__BUFFER_SIZE + 1);
        read_len = BZ2_bzRead(&rc, bz_file, buffer + length, PCMK__BUFFER_SIZE);

        if ((rc == BZ_OK) || (rc == BZ_STREAM_END)) {
            crm_trace("Read %ld bytes from file: %d", (long) read_len, rc);
            length += read_len;
        }
    } while (rc == BZ_OK);

    rc = pcmk__bzlib2rc(rc);
    if (rc != pcmk_rc_ok) {
        rc = pcmk__bzlib2rc(rc);
        crm_err("Could not read compressed %s: %s " CRM_XS " rc=%d",
                filename, pcmk_rc_str(rc), rc);
        free(buffer);
        buffer = NULL;
    } else {
        buffer[length] = '\0';
    }

done:
    BZ2_bzReadClose(&rc, bz_file);
    fclose(input);
    return buffer;
}

// @COMPAT Remove macro at 3.0.0 when we drop XML_PARSE_RECOVER
#define parse_xml_recover(result, fn, ...) do {                             \
        *result = fn(__VA_ARGS__, PCMK__XML_PARSE_OPTS_WITHOUT_RECOVER);    \
        if (*result == NULL) {                                              \
            *result = fn(__VA_ARGS__, PCMK__XML_PARSE_OPTS_WITH_RECOVER);   \
                                                                            \
            if (*result != NULL) {                                          \
                crm_warn("Successfully recovered from XML errors "          \
                         "(note: a future release will treat this as a "    \
                         "fatal failure)");                                 \
            }                                                               \
        }                                                                   \
    } while (0);

xmlNode *
pcmk__xml_read(const char *filename)
{
    bool use_stdin = pcmk__str_eq(filename, "-", pcmk__str_null_matches);
    xmlNode *xml = NULL;
    xmlDoc *output = NULL;
    xmlParserCtxt *ctxt = NULL;
    const xmlError *last_error = NULL;

    // Create a parser context
    ctxt = xmlNewParserCtxt();
    CRM_CHECK(ctxt != NULL, return NULL);

    xmlCtxtResetLastError(ctxt);
    xmlSetGenericErrorFunc(ctxt, pcmk__log_xmllib_err);

    if (use_stdin) {
        /* @COMPAT After dropping XML_PARSE_RECOVER, we can avoid capturing
         * stdin into a buffer and instead call
         * xmlCtxtReadFd(ctxt, STDIN_FILENO, NULL, NULL, XML_PARSE_NOBLANKS);
         *
         * For now we have to save the input so that we can use it twice.
         */
        char *input = read_stdin();

        if (input != NULL) {
            parse_xml_recover(&output, xmlCtxtReadDoc, ctxt, (pcmkXmlStr) input,
                              NULL, NULL);
            free(input);
        }

    } else if (pcmk__ends_with_ext(filename, ".bz2")) {
        char *input = decompress_file(filename);

        if (input != NULL) {
            parse_xml_recover(&output, xmlCtxtReadDoc, ctxt, (pcmkXmlStr) input,
                              NULL, NULL);
            free(input);
        }

    } else {
        parse_xml_recover(&output, xmlCtxtReadFile, ctxt, filename, NULL);
    }

    if (output != NULL) {
        xml = xmlDocGetRootElement(output);
        if (xml != NULL) {
            /* @TODO Should we really be stripping out text? This seems like an
             * overly broad way to get rid of whitespace, if that's the goal.
             * Text nodes may be invalid in most or all Pacemaker inputs, but
             * stripping them in a generic "parse XML from file" function may
             * not be the best way to ignore them.
             */
            pcmk__strip_xml_text(xml);
        }
    }

    // @COMPAT At 3.0.0, free xml and return NULL if xml != NULL on error
    last_error = xmlCtxtGetLastError(ctxt);
    if (last_error != NULL) {
        if (xml != NULL) {
            crm_log_xml_info(xml, "Partial");
        }
    }

    xmlFreeParserCtxt(ctxt);
    return xml;
}

xmlNode *
pcmk__xml_parse(const char *input)
{
    xmlNode *xml = NULL;
    xmlDoc *output = NULL;
    xmlParserCtxt *ctxt = NULL;
    const xmlError *last_error = NULL;

    if (input == NULL) {
        return NULL;
    }

    ctxt = xmlNewParserCtxt();
    if (ctxt == NULL) {
        return NULL;
    }

    xmlCtxtResetLastError(ctxt);
    xmlSetGenericErrorFunc(ctxt, pcmk__log_xmllib_err);

    parse_xml_recover(&output, xmlCtxtReadDoc, ctxt, (pcmkXmlStr) input, NULL,
                      NULL);

    if (output != NULL) {
        xml = xmlDocGetRootElement(output);
    }

    // @COMPAT At 3.0.0, free xml and return NULL if xml != NULL; update doxygen
    last_error = xmlCtxtGetLastError(ctxt);
    if (last_error != NULL) {
        if (xml != NULL) {
            crm_log_xml_info(xml, "Partial");
        }
    }

    xmlFreeParserCtxt(ctxt);
    return xml;
}

static void
dump_xml_element(const xmlNode *data, uint32_t options, GString *buffer,
                 int depth)
{
    bool pretty = pcmk_is_set(options, pcmk__xml_fmt_pretty);
    bool filtered = pcmk_is_set(options, pcmk__xml_fmt_filtered);
    int spaces = pretty? (2 * depth) : 0;

    for (int lpc = 0; lpc < spaces; lpc++) {
        g_string_append_c(buffer, ' ');
    }

    pcmk__g_strcat(buffer, "<", data->name, NULL);

    for (const xmlAttr *attr = pcmk__xe_first_attr(data); attr != NULL;
         attr = attr->next) {

        if (!filtered || !pcmk__xa_filterable((const char *) (attr->name))) {
            pcmk__dump_xml_attr(attr, buffer);
        }
    }

    if (data->children == NULL) {
        g_string_append(buffer, "/>");

    } else {
        g_string_append_c(buffer, '>');
    }

    if (pretty) {
        g_string_append_c(buffer, '\n');
    }

    if (data->children) {
        for (const xmlNode *child = data->children; child != NULL;
             child = child->next) {
            pcmk__xml_string(child, options, buffer, depth + 1);
        }

        for (int lpc = 0; lpc < spaces; lpc++) {
            g_string_append_c(buffer, ' ');
        }

        pcmk__g_strcat(buffer, "</", data->name, ">", NULL);

        if (pretty) {
            g_string_append_c(buffer, '\n');
        }
    }
}

static void
dump_xml_text(const xmlNode *data, uint32_t options, GString *buffer,
              int depth)
{
    bool pretty = pcmk_is_set(options, pcmk__xml_fmt_pretty);
    int spaces = pretty? (2 * depth) : 0;
    const char *content = (const char *) data->content;
    gchar *content_esc = NULL;

    if (pcmk__xml_needs_escape(content, pcmk__xml_escape_text)) {
        content_esc = pcmk__xml_escape(content, pcmk__xml_escape_text);
        content = content_esc;
    }

    for (int lpc = 0; lpc < spaces; lpc++) {
        g_string_append_c(buffer, ' ');
    }

    g_string_append(buffer, content);

    if (pretty) {
        g_string_append_c(buffer, '\n');
    }
    g_free(content_esc);
}

static void
dump_xml_cdata(const xmlNode *data, uint32_t options, GString *buffer,
               int depth)
{
    bool pretty = pcmk_is_set(options, pcmk__xml_fmt_pretty);
    int spaces = pretty? (2 * depth) : 0;

    for (int lpc = 0; lpc < spaces; lpc++) {
        g_string_append_c(buffer, ' ');
    }

    pcmk__g_strcat(buffer, "<![CDATA[", (const char *) data->content, "]]>",
                   NULL);

    if (pretty) {
        g_string_append_c(buffer, '\n');
    }
}

static void
dump_xml_comment(const xmlNode *data, uint32_t options, GString *buffer,
                 int depth)
{
    bool pretty = pcmk_is_set(options, pcmk__xml_fmt_pretty);
    int spaces = pretty? (2 * depth) : 0;

    for (int lpc = 0; lpc < spaces; lpc++) {
        g_string_append_c(buffer, ' ');
    }

    pcmk__g_strcat(buffer, "<!--", (const char *) data->content, "-->", NULL);

    if (pretty) {
        g_string_append_c(buffer, '\n');
    }
}

static const char *
xml_element_type_text(xmlElementType type)
{
    static const char *const element_type_names[] = {
        [XML_ELEMENT_NODE]       = "element",
        [XML_ATTRIBUTE_NODE]     = "attribute",
        [XML_TEXT_NODE]          = "text",
        [XML_CDATA_SECTION_NODE] = "CDATA section",
        [XML_ENTITY_REF_NODE]    = "entity reference",
        [XML_ENTITY_NODE]        = "entity",
        [XML_PI_NODE]            = "PI",
        [XML_COMMENT_NODE]       = "comment",
        [XML_DOCUMENT_NODE]      = "document",
        [XML_DOCUMENT_TYPE_NODE] = "document type",
        [XML_DOCUMENT_FRAG_NODE] = "document fragment",
        [XML_NOTATION_NODE]      = "notation",
        [XML_HTML_DOCUMENT_NODE] = "HTML document",
        [XML_DTD_NODE]           = "DTD",
        [XML_ELEMENT_DECL]       = "element declaration",
        [XML_ATTRIBUTE_DECL]     = "attribute declaration",
        [XML_ENTITY_DECL]        = "entity declaration",
        [XML_NAMESPACE_DECL]     = "namespace declaration",
        [XML_XINCLUDE_START]     = "XInclude start",
        [XML_XINCLUDE_END]       = "XInclude end",
    };

    if ((type < 0) || (type >= PCMK__NELEM(element_type_names))) {
        return "unrecognized type";
    }
    return element_type_names[type];
}

void
pcmk__xml_string(const xmlNode *data, uint32_t options, GString *buffer,
                 int depth)
{
    if (data == NULL) {
        crm_trace("Nothing to dump");
        return;
    }

    CRM_ASSERT(buffer != NULL);
    CRM_CHECK(depth >= 0, depth = 0);

    switch(data->type) {
        case XML_ELEMENT_NODE:
            /* Handle below */
            dump_xml_element(data, options, buffer, depth);
            break;
        case XML_TEXT_NODE:
            if (pcmk_is_set(options, pcmk__xml_fmt_text)) {
                dump_xml_text(data, options, buffer, depth);
            }
            break;
        case XML_COMMENT_NODE:
            dump_xml_comment(data, options, buffer, depth);
            break;
        case XML_CDATA_SECTION_NODE:
            dump_xml_cdata(data, options, buffer, depth);
            break;
        default:
            crm_warn("Cannot convert XML %s node to text " CRM_XS " type=%d",
                     xml_element_type_text(data->type), data->type);
            break;
    }
}

static int
write_compressed_stream(char *text, const char *filename, FILE *stream,
                        unsigned int *bytes_out)
{
    unsigned int bytes_in = 0;
    int rc = pcmk_rc_ok;

    // (5, 0, 0): (intermediate block size, silent, default workFactor)
    BZFILE *bz_file = BZ2_bzWriteOpen(&rc, stream, 5, 0, 0);

    rc = pcmk__bzlib2rc(rc);
    if (rc != pcmk_rc_ok) {
        crm_warn("Not compressing %s: could not prepare file stream: %s "
                 CRM_XS " rc=%d",
                 filename, pcmk_rc_str(rc), rc);
        goto done;
    }

    BZ2_bzWrite(&rc, bz_file, text, strlen(text));
    rc = pcmk__bzlib2rc(rc);
    if (rc != pcmk_rc_ok) {
        crm_warn("Not compressing %s: could not compress data: %s "
                 CRM_XS " rc=%d errno=%d",
                 filename, pcmk_rc_str(rc), rc, errno);
        goto done;
    }

    BZ2_bzWriteClose(&rc, bz_file, 0, &bytes_in, bytes_out);
    bz_file = NULL;
    rc = pcmk__bzlib2rc(rc);
    if (rc != pcmk_rc_ok) {
        crm_warn("Not compressing %s: could not write compressed data: %s "
                 CRM_XS " rc=%d errno=%d",
                 filename, pcmk_rc_str(rc), rc, errno);
        goto done;
    }

    crm_trace("Compressed XML for %s from %u bytes to %u",
              filename, bytes_in, *bytes_out);

done:
    if (bz_file != NULL) {
        BZ2_bzWriteClose(&rc, bz_file, 0, NULL, NULL);
    }
    return rc;
}

static int
write_xml_stream(const xmlNode *xml, const char *filename, FILE *stream,
                 bool compress, unsigned int *nbytes)
{
    // @COMPAT Drop nbytes as arg when we drop write_xml_fd()/write_xml_file()
    GString *buffer = g_string_sized_new(1024);
    unsigned int bytes_out = 0;
    int rc = pcmk_rc_ok;

    pcmk__xml_string(xml, pcmk__xml_fmt_pretty, buffer, 0);
    CRM_CHECK(!pcmk__str_empty(buffer->str),
              crm_log_xml_info(xml, "dump-failed");
              rc = pcmk_rc_error;
              goto done);

    crm_log_xml_trace(xml, "writing");

    if (compress
        && (write_compressed_stream(buffer->str, filename, stream,
                                    &bytes_out) == pcmk_rc_ok)) {
        goto done;
    }

    rc = fprintf(stream, "%s", buffer->str);
    if (rc < 0) {
        rc = EIO;
        crm_perror(LOG_ERR, "writing %s", filename);
        goto done;
    }
    bytes_out = (unsigned int) rc;
    rc = pcmk_rc_ok;

done:
    if (fflush(stream) != 0) {
        rc = errno;
        crm_perror(LOG_ERR, "flushing %s", filename);
    }

    // Don't report error if the file does not support synchronization
    if ((fsync(fileno(stream)) < 0) && (errno != EROFS) && (errno != EINVAL)) {
        rc = errno;
        crm_perror(LOG_ERR, "synchronizing %s", filename);
    }

    fclose(stream);
    crm_trace("Saved %u bytes to %s as XML", bytes_out, filename);

    if (nbytes != NULL) {
        *nbytes = bytes_out;
    }
    g_string_free(buffer, TRUE);
    return rc;
}

int
pcmk__xml_write_fd(const xmlNode *xml, const char *filename, int fd,
                   bool compress, unsigned int *nbytes)
{
    // @COMPAT Drop compress and nbytes arguments when we drop write_xml_fd()
    FILE *stream = NULL;

    CRM_CHECK((xml != NULL) && (fd > 0), return EINVAL);
    stream = fdopen(fd, "w");
    if (stream == NULL) {
        return errno;
    }

    return write_xml_stream(xml, pcmk__s(filename, "unnamed file"), stream,
                            compress, nbytes);
}

int
pcmk__xml_write_file(const xmlNode *xml, const char *filename, bool compress,
                     unsigned int *nbytes)
{
    // @COMPAT Drop nbytes argument when we drop write_xml_fd()
    FILE *stream = NULL;

    CRM_CHECK((xml != NULL) && (filename != NULL), return EINVAL);
    stream = fopen(filename, "w");
    if (stream == NULL) {
        return errno;
    }

    return write_xml_stream(xml, filename, stream, compress, nbytes);
}

int
pcmk__xml2fd(int fd, xmlNode *cur)
{
    bool success;

    xmlOutputBuffer *fd_out = xmlOutputBufferCreateFd(fd, NULL);
    pcmk__mem_assert(fd_out);
    xmlNodeDumpOutput(fd_out, cur->doc, cur, 0, pcmk__xml_fmt_pretty, NULL);

    success = xmlOutputBufferWrite(fd_out, sizeof("\n") - 1, "\n") != -1;

    success = xmlOutputBufferClose(fd_out) != -1 && success;

    if (!success) {
        return EIO;
    }

    fsync(fd);
    return pcmk_rc_ok;
}

void
save_xml_to_file(const xmlNode *xml, const char *desc, const char *filename)
{
    char *f = NULL;

    if (filename == NULL) {
        char *uuid = crm_generate_uuid();

        f = crm_strdup_printf("%s/%s", pcmk__get_tmpdir(), uuid);
        filename = f;
        free(uuid);
    }

    crm_info("Saving %s to %s", desc, filename);
    pcmk__xml_write_file(xml, filename, false, NULL);
    free(f);
}


// Deprecated functions kept only for backward API compatibility
// LCOV_EXCL_START

#include <crm/common/xml_io_compat.h>

xmlNode *
filename2xml(const char *filename)
{
    return pcmk__xml_read(filename);
}

xmlNode *
stdin2xml(void)
{
    return pcmk__xml_read(NULL);
}

xmlNode *
string2xml(const char *input)
{
    return pcmk__xml_parse(input);
}

char *
dump_xml_formatted(const xmlNode *xml)
{
    char *str = NULL;
    GString *buffer = g_string_sized_new(1024);

    pcmk__xml_string(xml, pcmk__xml_fmt_pretty, buffer, 0);

    str = pcmk__str_copy(buffer->str);
    g_string_free(buffer, TRUE);
    return str;
}

char *
dump_xml_formatted_with_text(const xmlNode *xml)
{
    char *str = NULL;
    GString *buffer = g_string_sized_new(1024);

    pcmk__xml_string(xml, pcmk__xml_fmt_pretty|pcmk__xml_fmt_text, buffer, 0);

    str = pcmk__str_copy(buffer->str);
    g_string_free(buffer, TRUE);
    return str;
}

char *
dump_xml_unformatted(const xmlNode *xml)
{
    char *str = NULL;
    GString *buffer = g_string_sized_new(1024);

    pcmk__xml_string(xml, 0, buffer, 0);

    str = pcmk__str_copy(buffer->str);
    g_string_free(buffer, TRUE);
    return str;
}

int
write_xml_fd(const xmlNode *xml, const char *filename, int fd,
             gboolean compress)
{
    unsigned int nbytes = 0;
    int rc = pcmk__xml_write_fd(xml, filename, fd, compress, &nbytes);

    if (rc != pcmk_rc_ok) {
        return pcmk_rc2legacy(rc);
    }
    return (int) nbytes;
}

int
write_xml_file(const xmlNode *xml, const char *filename, gboolean compress)
{
    unsigned int nbytes = 0;
    int rc = pcmk__xml_write_file(xml, filename, compress, &nbytes);

    if (rc != pcmk_rc_ok) {
        return pcmk_rc2legacy(rc);
    }
    return (int) nbytes;
}

// LCOV_EXCL_STOP
// End deprecated API