showq_json.c

[詳解]

/*++
/* NAME
/*  showq_json 8
/* SUMMARY
/*  JSON queue status formatter
/* SYNOPSIS
/*  void    showq_json(
/*  VSTREAM *showq)
/* DESCRIPTION
/*  This function converts showq(8) daemon output to JSON format.
/* DIAGNOSTICS
/*  Fatal errors: out of memory, malformed showq(8) daemon output.
/* LICENSE
/* .ad
/* .fi
/*  The Secure Mailer license must be distributed with this software.
/* AUTHOR(S)
/*  Wietse Venema
/*  IBM T.J. Watson Research
/*  P.O. Box 704
/*  Yorktown Heights, NY 10598, USA
/*
/*  Wietse Venema
/*  Google, Inc.
/*  111 8th Avenue
/*  New York, NY 10011, USA
/*--*/

/* System library. */

#include <sys_defs.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sysexits.h>
#include <ctype.h>
#include <errno.h>

/* Utility library. */

#include <vstring.h>
#include <vstream.h>
#include <stringops.h>
#include <mymalloc.h>
#include <msg.h>

/* Global library. */

#include <mail_proto.h>
#include <mail_queue.h>
#include <mail_date.h>
#include <mail_params.h>

/* Application-specific. */

#include <postqueue.h>

#define STR(x)  vstring_str(x)
#define LEN(x)  VSTRING_LEN(x)

/* json_quote - quote JSON string */

static char *json_quote(VSTRING *result, const char *text)
{
    unsigned char *cp;
    int     ch;

    /*
     * We use short escape sequences for common control characters. Note that
     * RFC 4627 allows "/" (0x2F) to be sent without quoting. Differences
     * with RFC 4627: we send DEL (0x7f) as \u007F; the result remains RFC
     * 4627 complaint.
     */
    VSTRING_RESET(result);
    for (cp = (unsigned char *) text; (ch = *cp) != 0; cp++) {
    if (UNEXPECTED(ISCNTRL(ch))) {
        switch (ch) {
        case '\b':
        VSTRING_ADDCH(result, '\\');
        VSTRING_ADDCH(result, 'b');
        break;
        case '\f':
        VSTRING_ADDCH(result, '\\');
        VSTRING_ADDCH(result, 'f');
        break;
        case '\n':
        VSTRING_ADDCH(result, '\\');
        VSTRING_ADDCH(result, 'n');
        break;
        case '\r':
        VSTRING_ADDCH(result, '\\');
        VSTRING_ADDCH(result, 'r');
        break;
        case '\t':
        VSTRING_ADDCH(result, '\\');
        VSTRING_ADDCH(result, 't');
        break;
        default:
        vstring_sprintf(result, "\\u%04X", ch);
        break;
        }
    } else {
        switch (ch) {
        case '\\':
        case '"':
        VSTRING_ADDCH(result, '\\');
        /* FALLTHROUGH */
        default:
        VSTRING_ADDCH(result, ch);
        break;
        }
    }
    }
    VSTRING_TERMINATE(result);

    /*
     * Force the result to be UTF-8 (with SMTPUTF8 enabled) or ASCII (with
     * SMTPUTF8 disabled).
     */
    printable(STR(result), '?');
    return (STR(result));
}

/* json_message - report status for one message */

static void format_json(VSTREAM *showq_stream)
{
    static VSTRING *queue_name = 0;
    static VSTRING *queue_id = 0;
    static VSTRING *addr = 0;
    static VSTRING *why = 0;
    static VSTRING *quote_buf = 0;
    long    arrival_time;
    long    message_size;
    int     showq_status;
    int     rcpt_count = 0;

    /*
     * One-time initialization.
     */
    if (queue_name == 0) {
    queue_name = vstring_alloc(100);
    queue_id = vstring_alloc(100);
    addr = vstring_alloc(100);
    why = vstring_alloc(100);
    quote_buf = vstring_alloc(100);
    }

    /*
     * Read the message properties and sender address.
     */
    if (attr_scan(showq_stream, ATTR_FLAG_MORE | ATTR_FLAG_STRICT,
          RECV_ATTR_STR(MAIL_ATTR_QUEUE, queue_name),
          RECV_ATTR_STR(MAIL_ATTR_QUEUEID, queue_id),
          RECV_ATTR_LONG(MAIL_ATTR_TIME, &arrival_time),
          RECV_ATTR_LONG(MAIL_ATTR_SIZE, &message_size),
          RECV_ATTR_STR(MAIL_ATTR_SENDER, addr),
          ATTR_TYPE_END) != 5)
    msg_fatal_status(EX_SOFTWARE, "malformed showq server response");
    vstream_printf("{");
    vstream_printf("\"queue_name\": \"%s\", ",
           json_quote(quote_buf, STR(queue_name)));
    vstream_printf("\"queue_id\": \"%s\", ",
           json_quote(quote_buf, STR(queue_id)));
    vstream_printf("\"arrival_time\": %ld, ", arrival_time);
    vstream_printf("\"message_size\": %ld, ", message_size);
    vstream_printf("\"sender\": \"%s\", ",
           json_quote(quote_buf, STR(addr)));

    /*
     * Read zero or more (recipient, reason) pair(s) until attr_scan_more()
     * consumes a terminator. If the showq daemon messes up, don't try to
     * resynchronize.
     */
    vstream_printf("\"recipients\": [");
    for (rcpt_count = 0; (showq_status = attr_scan_more(showq_stream)) > 0; rcpt_count++) {
    if (rcpt_count > 0)
        vstream_printf(", ");
    vstream_printf("{");
    if (attr_scan(showq_stream, ATTR_FLAG_MORE | ATTR_FLAG_STRICT,
              RECV_ATTR_STR(MAIL_ATTR_RECIP, addr),
              RECV_ATTR_STR(MAIL_ATTR_WHY, why),
              ATTR_TYPE_END) != 2)
        msg_fatal_status(EX_SOFTWARE, "malformed showq server response");
    vstream_printf("\"address\": \"%s\"",
               json_quote(quote_buf, STR(addr)));
    if (LEN(why) > 0)
        vstream_printf(", \"delay_reason\": \"%s\"",
               json_quote(quote_buf, STR(why)));
    vstream_printf("}");
    }
    vstream_printf("]");
    if (showq_status < 0)
    msg_fatal_status(EX_SOFTWARE, "malformed showq server response");
    vstream_printf("}\n");
    if (vstream_fflush(VSTREAM_OUT) && errno != EPIPE)
    msg_fatal_status(EX_IOERR, "output write error: %m");
}

/* showq_json - streaming JSON-format output adapter */

void    showq_json(VSTREAM *showq_stream)
{
    int     showq_status;

    /*
     * Emit zero or more queue file objects until attr_scan_more() consumes a
     * terminator.
     */
    while ((showq_status = attr_scan_more(showq_stream)) > 0
       && vstream_ferror(VSTREAM_OUT) == 0) {
    format_json(showq_stream);
    }
    if (showq_status < 0)
    msg_fatal_status(EX_SOFTWARE, "malformed showq server response");
}