tools.c

snmp up 2

/*
 * tools.c
 */

#include <net-snmp/net-snmp-config.h>

#include <ctype.h>
#include <stdio.h>
#include <sys/types.h>
#if TIME_WITH_SYS_TIME
# ifdef WIN32
#  include <sys/timeb.h>
# else
#  include <sys/time.h>
# endif
# include <time.h>
#else
# if HAVE_SYS_TIME_H
#  include <sys/time.h>
# else
#  include <time.h>
# endif
#endif
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#if HAVE_WINSOCK_H
#include <winsock.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#if HAVE_STRING_H
#include <string.h>
#else
#include <strings.h>
#endif
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif

#if HAVE_DMALLOC_H
#include <dmalloc.h>
#endif

#include <net-snmp/types.h>
#include <net-snmp/output_api.h>
#include <net-snmp/utilities.h>
#include <net-snmp/library/tools.h>     /* for "internal" definitions */

#include <net-snmp/library/snmp_api.h>
#include <net-snmp/library/mib.h>
#include <net-snmp/library/scapi.h>


/*
 * snmp_realloc:
 * 
 * Parameters:
 * 
 * buf  pointer to a buffer pointer
 * buf_len      pointer to current size of buffer in bytes
 * 
 * This function increase the size of the buffer pointed at by *buf, which is
 * initially of size *buf_len.  Contents are preserved **AT THE BOTTOM END OF
 * THE BUFFER**.  If memory can be (re-)allocated then it returns 1, else it
 * returns 0.
 * 
 */

int
snmp_realloc(u_char ** buf, size_t * buf_len)
{
    u_char         *new_buf = NULL;
    size_t          new_buf_len = 0;

    if (buf == NULL) {
        return 0;
    }

    /*
     * The current re-allocation algorithm is to increase the buffer size by
     * whichever is the greater of 256 bytes or the current buffer size, up to
     * a maximum increase of 8192 bytes.  
     */

    if (*buf_len <= 255) {
        new_buf_len = *buf_len + 256;
    } else if (*buf_len > 255 && *buf_len <= 8191) {
        new_buf_len = *buf_len * 2;
    } else if (*buf_len > 8191) {
        new_buf_len = *buf_len + 8192;
    }

    if (*buf == NULL) {
        new_buf = (u_char *) malloc(new_buf_len);
    } else {
        new_buf = (u_char *) realloc(*buf, new_buf_len);
    }

    if (new_buf != NULL) {
        *buf = new_buf;
        *buf_len = new_buf_len;
        return 1;
    } else {
        return 0;
    }
}

int
snmp_strcat(u_char ** buf, size_t * buf_len, size_t * out_len,
            int allow_realloc, const u_char * s)
{
    if (buf == NULL || buf_len == NULL || out_len == NULL) {
        return 0;
    }

    if (s == NULL) {
        /*
         * Appending a NULL string always succeeds since it is a NOP.  
         */
        return 1;
    }

    while ((*out_len + strlen((const char *) s) + 1) >= *buf_len) {
        if (!(allow_realloc && snmp_realloc(buf, buf_len))) {
            return 0;
        }
    }

    strcpy((char *) (*buf + *out_len), (const char *) s);
    *out_len += strlen((char *) (*buf + *out_len));
    return 1;
}

/*******************************************************************-o-******
 * free_zero
 *
 * Parameters:
 *	*buf	Pointer at bytes to free.
 *	size	Number of bytes in buf.
 */
void
free_zero(void *buf, size_t size)
{
    if (buf) {
        memset(buf, 0, size);
        free(buf);
    }

}                               /* end free_zero() */




/*******************************************************************-o-******
 * malloc_random
 *
 * Parameters:
 *	size	Number of bytes to malloc() and fill with random bytes.
 *      
 * Returns pointer to allocaed & set buffer on success, size contains
 * number of random bytes filled.
 *
 * buf is NULL and *size set to KMT error value upon failure.
 *
 */
u_char         *
malloc_random(size_t * size)
{
    int             rval = SNMPERR_SUCCESS;
    u_char         *buf = (u_char *) calloc(1, *size);

    if (buf) {
        rval = sc_random(buf, size);

        if (rval < 0) {
            free_zero(buf, *size);
            buf = NULL;
        } else {
            *size = rval;
        }
    }

    return buf;

}                               /* end malloc_random() */




/*******************************************************************-o-******
 * memdup
 *
 * Parameters:
 *	to       Pointer to allocate and copy memory to.
 *      from     Pointer to copy memory from.
 *      size     Size of the data to be copied.
 *      
 * Returns
 *	SNMPERR_SUCCESS	On success.
 *      SNMPERR_GENERR	On failure.
 */
int
memdup(u_char ** to, const u_char * from, size_t size)
{
    if (to == NULL)
        return SNMPERR_GENERR;
    if (from == NULL) {
        *to = NULL;
        return SNMPERR_SUCCESS;
    }
    if ((*to = (u_char *) malloc(size)) == NULL)
        return SNMPERR_GENERR;
    memcpy(*to, from, size);
    return SNMPERR_SUCCESS;

}                               /* end memdup() */

/** copies a (possible) unterminated string of a given length into a
 *  new buffer and null terminates it as well (new buffer MAY be one
 *  byte longer to account for this */
char           *
netsnmp_strdup_and_null(const u_char * from, size_t from_len)
{
    u_char         *ret;

    if (from_len == 0 || from[from_len - 1] != '\0') {
        ret = malloc(from_len + 1);
        if (!ret)
            return NULL;
        ret[from_len] = '\0';
    } else {
        ret = malloc(from_len);
        if (!ret)
            return NULL;
        ret[from_len - 1] = '\0';
    }
    memcpy(ret, from, from_len);
    return ret;
}

/*******************************************************************-o-******
 * binary_to_hex
 *
 * Parameters:
 *	*input		Binary data.
 *	len		Length of binary data.
 *	**output	NULL terminated string equivalent in hex.
 *      
 * Returns:
 *	olen	Length of output string not including NULL terminator.
 *
 * FIX	Is there already one of these in the UCD SNMP codebase?
 *	The old one should be used, or this one should be moved to
 *	snmplib/snmp_api.c.
 */
u_int
binary_to_hex(const u_char * input, size_t len, char **output)
{
    u_int           olen = (len * 2) + 1;
    char           *s = (char *) calloc(1, olen), *op = s;
    const u_char   *ip = input;


    while (ip - input < (int) len) {
        *op++ = VAL2HEX((*ip >> 4) & 0xf);
        *op++ = VAL2HEX(*ip & 0xf);
        ip++;
    }
    *op = '\0';

    *output = s;
    return olen;

}                               /* end binary_to_hex() */




/*******************************************************************-o-******
 * hex_to_binary2
 *
 * Parameters:
 *	*input		Printable data in base16.
 *	len		Length in bytes of data.
 *	**output	Binary data equivalent to input.
 *      
 * Returns:
 *	SNMPERR_GENERR	Failure.
 *	<len>		Otherwise, Length of allocated string.
 *
 *
 * Input of an odd length is right aligned.
 *
 * FIX	Another version of "hex-to-binary" which takes odd length input
 *	strings.  It also allocates the memory to hold the binary data.
 *	Should be integrated with the official hex_to_binary() function.
 */
int
hex_to_binary2(const u_char * input, size_t len, char **output)
{
    u_int           olen = (len / 2) + (len % 2);
    char           *s = (char *) calloc(1, (olen) ? olen : 1), *op = s;
    const u_char   *ip = input;


    *output = NULL;
    *op = 0;
    if (len % 2) {
        if (!isxdigit(*ip))
            goto hex_to_binary2_quit;
        *op++ = HEX2VAL(*ip);
        ip++;
    }

    while (ip - input < (int) len) {
        if (!isxdigit(*ip))
            goto hex_to_binary2_quit;
        *op = HEX2VAL(*ip) << 4;
        ip++;

        if (!isxdigit(*ip))
            goto hex_to_binary2_quit;
        *op++ += HEX2VAL(*ip);
        ip++;
    }

    *output = s;
    return olen;

  hex_to_binary2_quit:
    free_zero(s, olen);
    return -1;

}                               /* end hex_to_binary2() */

int
snmp_decimal_to_binary(u_char ** buf, size_t * buf_len, size_t * out_len,
                       int allow_realloc, const char *decimal)
{
    int             subid = 0;
    const char     *cp = decimal;

    if (buf == NULL || buf_len == NULL || out_len == NULL
        || decimal == NULL) {
        return 0;
    }

    while (*cp != '\0') {
        if (isspace((int) *cp) || *cp == '.') {
            cp++;
            continue;
        }
        if (!isdigit((int) *cp)) {
            return 0;
        }
        if ((subid = atoi(cp)) > 255) {
            return 0;
        }
        if ((*out_len >= *buf_len) &&
            !(allow_realloc && snmp_realloc(buf, buf_len))) {
            return 0;
        }
        *(*buf + *out_len) = (u_char) subid;
        (*out_len)++;
        while (isdigit((int) *cp)) {
            cp++;
        }
    }
    return 1;
}

int
snmp_hex_to_binary(u_char ** buf, size_t * buf_len, size_t * out_len,
                   int allow_realloc, const char *hex)
{
    int             subid = 0;
    const char     *cp = hex;

    if (buf == NULL || buf_len == NULL || out_len == NULL || hex == NULL) {
        return 0;
    }

    if ((*cp == '0') && ((*(cp + 1) == 'x') || (*(cp + 1) == 'X'))) {
        cp += 2;
    }

    while (*cp != '\0') {
        if (isspace((int) *cp)) {
            cp++;
            continue;
        }
        if (!isxdigit((int) *cp)) {
            return 0;
        }
        if (sscanf(cp, "%2x", &subid) == 0) {
            return 0;
        }
        if ((*out_len >= *buf_len) &&
            !(allow_realloc && snmp_realloc(buf, buf_len))) {
            return 0;
        }
        *(*buf + *out_len) = (u_char) subid;
        (*out_len)++;
        if (*++cp == '\0') {
            /*
             * Odd number of hex digits is an error.  
             */
            return 0;
        } else {
            cp++;
        }
    }
    return 1;
}