util.c

#include <stdio.h>
#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <stdarg.h>

#include "memcached.h"

static char *uriencode_map[256];
static char uriencode_str[768];

void uriencode_init(void) {
    int x;
    char *str = uriencode_str;
    for (x = 0; x < 256; x++) {
        if (isalnum(x) || x == '-' || x == '.' || x == '_' || x == '~') {
            uriencode_map[x] = NULL;
        } else {
            snprintf(str, 4, "%%%02hhX", (unsigned char)x);
            uriencode_map[x] = str;
            str += 3; /* lobbing off the \0 is fine */
        }
    }
}

bool uriencode(const char *src, char *dst, const size_t srclen, const size_t dstlen) {
    int x;
    size_t d = 0;
    for (x = 0; x < srclen; x++) {
        if (d + 4 > dstlen)
            return false;
        if (uriencode_map[(unsigned char) src[x]] != NULL) {
            memcpy(&dst[d], uriencode_map[(unsigned char) src[x]], 3);
            d += 3;
        } else {
            dst[d] = src[x];
            d++;
        }
    }
    dst[d] = '\0';
    return true;
}

/* Avoid warnings on solaris, where isspace() is an index into an array, and gcc uses signed chars */
#define xisspace(c) isspace((unsigned char)c)

bool safe_strtoull(const char *str, uint64_t *out) {
    assert(out != NULL);
    errno = 0;
    *out = 0;
    char *endptr;
    unsigned long long ull = strtoull(str, &endptr, 10);
    if ((errno == ERANGE) || (str == endptr)) {
        return false;
    }

    if (xisspace(*endptr) || (*endptr == '\0' && endptr != str)) {
        if ((long long) ull < 0) {
            /* only check for negative signs in the uncommon case when
             * the unsigned number is so big that it's negative as a
             * signed number. */
            if (strchr(str, '-') != NULL) {
                return false;
            }
        }
        *out = ull;
        return true;
    }
    return false;
}

/* Could macro this. Decided to keep this unrolled for safety rather than add
 * the base parameter to all callers. Very few places need to parse a number
 * outside of base 10, currently exactly once, so splitting this up should
 * help avoid typo bugs.
 */
bool safe_strtoull_hex(const char *str, uint64_t *out) {
    assert(out != NULL);
    errno = 0;
    *out = 0;
    char *endptr;
    unsigned long long ull = strtoull(str, &endptr, 16);
    if ((errno == ERANGE) || (str == endptr)) {
        return false;
    }

    if (xisspace(*endptr) || (*endptr == '\0' && endptr != str)) {
        if ((long long) ull < 0) {
            /* only check for negative signs in the uncommon case when
             * the unsigned number is so big that it's negative as a
             * signed number. */
            if (strchr(str, '-') != NULL) {
                return false;
            }
        }
        *out = ull;
        return true;
    }
    return false;
}

bool safe_strtoll(const char *str, int64_t *out) {
    assert(out != NULL);
    errno = 0;
    *out = 0;
    char *endptr;
    long long ll = strtoll(str, &endptr, 10);
    if ((errno == ERANGE) || (str == endptr)) {
        return false;
    }

    if (xisspace(*endptr) || (*endptr == '\0' && endptr != str)) {
        *out = ll;
        return true;
    }
    return false;
}

bool safe_strtoul(const char *str, uint32_t *out) {
    char *endptr = NULL;
    unsigned long l = 0;
    assert(out);
    assert(str);
    *out = 0;
    errno = 0;

    l = strtoul(str, &endptr, 10);
    if ((errno == ERANGE) || (str == endptr)) {
        return false;
    }

    if (xisspace(*endptr) || (*endptr == '\0' && endptr != str)) {
        if ((long) l < 0) {
            /* only check for negative signs in the uncommon case when
             * the unsigned number is so big that it's negative as a
             * signed number. */
            if (strchr(str, '-') != NULL) {
                return false;
            }
        }
        *out = l;
        return true;
    }

    return false;
}

bool safe_strtol(const char *str, int32_t *out) {
    assert(out != NULL);
    errno = 0;
    *out = 0;
    char *endptr;
    long l = strtol(str, &endptr, 10);
    if ((errno == ERANGE) || (str == endptr)) {
        return false;
    }

    if (xisspace(*endptr) || (*endptr == '\0' && endptr != str)) {
        *out = l;
        return true;
    }
    return false;
}

bool safe_strtod(const char *str, double *out) {
    assert(out != NULL);
    errno = 0;
    *out = 0;
    char *endptr;
    double d = strtod(str, &endptr);
    if ((errno == ERANGE) || (str == endptr)) {
        return false;
    }

    if (xisspace(*endptr) || (*endptr == '\0' && endptr != str)) {
        *out = d;
        return true;
    }
    return false;
}

// slow, safe function for copying null terminated buffers.
// ensures null terminator set on destination buffer. copies at most dstmax-1
// non-null bytes.
// Explicitly avoids over-reading src while looking for the null byte.
// returns true if src was fully copied.
// returns false if src was truncated into dst.
bool safe_strcpy(char *dst, const char *src, const size_t dstmax) {
   size_t x;

   for (x = 0; x < dstmax - 1 && src[x] != '\0'; x++) {
        dst[x] = src[x];
   }

   dst[x] = '\0';

   if (src[x] == '\0') {
       return true;
   } else {
       return false;
   }
}

bool safe_memcmp(const void *a, const void *b, size_t len) {
    const volatile unsigned char *ua = (const volatile unsigned char *)a;
    const volatile unsigned char *ub = (const volatile unsigned char *)b;
    int delta = 0;
    size_t x;

    for (x = 0; x < len; x++) {
        delta |= ua[x] ^ ub[x];
    }

    if (delta == 0) {
        return true;
    } else {
        return false;
    }
}

void vperror(const char *fmt, ...) {
    int old_errno = errno;
    char buf[1024];
    va_list ap;

    va_start(ap, fmt);
    if (vsnprintf(buf, sizeof(buf), fmt, ap) == -1) {
        buf[sizeof(buf) - 1] = '\0';
    }
    va_end(ap);

    errno = old_errno;

    perror(buf);
}

#ifndef HAVE_HTONLL
static uint64_t mc_swap64(uint64_t in) {
#ifdef ENDIAN_LITTLE
    /* Little endian, flip the bytes around until someone makes a faster/better
    * way to do this. */
    int64_t rv = 0;
    int i = 0;
     for(i = 0; i<8; i++) {
        rv = (rv << 8) | (in & 0xff);
        in >>= 8;
     }
    return rv;
#else
    /* big-endian machines don't need byte swapping */
    return in;
#endif
}

uint64_t ntohll(uint64_t val) {
   return mc_swap64(val);
}

uint64_t htonll(uint64_t val) {
   return mc_swap64(val);
}
#endif