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xemu/util/cutils.c
Marc-André Lureau 282468c7c4 include: move qemu_fdatasync() to osdep 
Move QEMU-specific code to util/osdep.c, so cutils can become a common
subproject.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20220420132624.2439741-22-marcandre.lureau@redhat.com>
2022-04-21 17:03:51 +04:00

972 lines
25 KiB
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/*
* Simple C functions to supplement the C library
*
* Copyright (c) 2006 Fabrice Bellard
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
#include "qemu/host-utils.h"
#include <math.h>
#include "qemu/ctype.h"
#include "qemu/cutils.h"
#include "qemu/error-report.h"
void strpadcpy(char *buf, int buf_size, const char *str, char pad)
{
int len = qemu_strnlen(str, buf_size);
memcpy(buf, str, len);
memset(buf + len, pad, buf_size - len);
}
void pstrcpy(char *buf, int buf_size, const char *str)
{
int c;
char *q = buf;
if (buf_size <= 0)
return;
for(;;) {
c = *str++;
if (c == 0 || q >= buf + buf_size - 1)
break;
*q++ = c;
}
*q = '\0';
}
/* strcat and truncate. */
char *pstrcat(char *buf, int buf_size, const char *s)
{
int len;
len = strlen(buf);
if (len < buf_size)
pstrcpy(buf + len, buf_size - len, s);
return buf;
}
int strstart(const char *str, const char *val, const char **ptr)
{
const char *p, *q;
p = str;
q = val;
while (*q != '\0') {
if (*p != *q)
return 0;
p++;
q++;
}
if (ptr)
*ptr = p;
return 1;
}
int stristart(const char *str, const char *val, const char **ptr)
{
const char *p, *q;
p = str;
q = val;
while (*q != '\0') {
if (qemu_toupper(*p) != qemu_toupper(*q))
return 0;
p++;
q++;
}
if (ptr)
*ptr = p;
return 1;
}
/* XXX: use host strnlen if available ? */
int qemu_strnlen(const char *s, int max_len)
{
int i;
for(i = 0; i < max_len; i++) {
if (s[i] == '\0') {
break;
}
}
return i;
}
char *qemu_strsep(char **input, const char *delim)
{
char *result = *input;
if (result != NULL) {
char *p;
for (p = result; *p != '\0'; p++) {
if (strchr(delim, *p)) {
break;
}
}
if (*p == '\0') {
*input = NULL;
} else {
*p = '\0';
*input = p + 1;
}
}
return result;
}
time_t mktimegm(struct tm *tm)
{
time_t t;
int y = tm->tm_year + 1900, m = tm->tm_mon + 1, d = tm->tm_mday;
if (m < 3) {
m += 12;
y--;
}
t = 86400ULL * (d + (153 * m - 457) / 5 + 365 * y + y / 4 - y / 100 +
y / 400 - 719469);
t += 3600 * tm->tm_hour + 60 * tm->tm_min + tm->tm_sec;
return t;
}
static int64_t suffix_mul(char suffix, int64_t unit)
{
switch (qemu_toupper(suffix)) {
case 'B':
return 1;
case 'K':
return unit;
case 'M':
return unit * unit;
case 'G':
return unit * unit * unit;
case 'T':
return unit * unit * unit * unit;
case 'P':
return unit * unit * unit * unit * unit;
case 'E':
return unit * unit * unit * unit * unit * unit;
}
return -1;
}
/*
* Convert size string to bytes.
*
* The size parsing supports the following syntaxes
* - 12345 - decimal, scale determined by @default_suffix and @unit
* - 12345{bBkKmMgGtTpPeE} - decimal, scale determined by suffix and @unit
* - 12345.678{kKmMgGtTpPeE} - decimal, scale determined by suffix, and
* fractional portion is truncated to byte
* - 0x7fEE - hexadecimal, unit determined by @default_suffix
*
* The following cause a deprecation warning, and may be removed in the future
* - 0xabc{kKmMgGtTpP} - hex with scaling suffix
*
* The following are intentionally not supported
* - octal, such as 08
* - fractional hex, such as 0x1.8
* - floating point exponents, such as 1e3
*
* The end pointer will be returned in *end, if not NULL. If there is
* no fraction, the input can be decimal or hexadecimal; if there is a
* fraction, then the input must be decimal and there must be a suffix
* (possibly by @default_suffix) larger than Byte, and the fractional
* portion may suffer from precision loss or rounding. The input must
* be positive.
*
* Return -ERANGE on overflow (with *@end advanced), and -EINVAL on
* other error (with *@end left unchanged).
*/
static int do_strtosz(const char *nptr, const char **end,
const char default_suffix, int64_t unit,
uint64_t *result)
{
int retval;
const char *endptr, *f;
unsigned char c;
bool hex = false;
uint64_t val, valf = 0;
int64_t mul;
/* Parse integral portion as decimal. */
retval = qemu_strtou64(nptr, &endptr, 10, &val);
if (retval) {
goto out;
}
if (memchr(nptr, '-', endptr - nptr) != NULL) {
endptr = nptr;
retval = -EINVAL;
goto out;
}
if (val == 0 && (*endptr == 'x' || *endptr == 'X')) {
/* Input looks like hex, reparse, and insist on no fraction. */
retval = qemu_strtou64(nptr, &endptr, 16, &val);
if (retval) {
goto out;
}
if (*endptr == '.') {
endptr = nptr;
retval = -EINVAL;
goto out;
}
hex = true;
} else if (*endptr == '.') {
/*
* Input looks like a fraction. Make sure even 1.k works
* without fractional digits. If we see an exponent, treat
* the entire input as invalid instead.
*/
double fraction;
f = endptr;
retval = qemu_strtod_finite(f, &endptr, &fraction);
if (retval) {
endptr++;
} else if (memchr(f, 'e', endptr - f) || memchr(f, 'E', endptr - f)) {
endptr = nptr;
retval = -EINVAL;
goto out;
} else {
/* Extract into a 64-bit fixed-point fraction. */
valf = (uint64_t)(fraction * 0x1p64);
}
}
c = *endptr;
mul = suffix_mul(c, unit);
if (mul > 0) {
if (hex) {
warn_report("Using a multiplier suffix on hex numbers "
"is deprecated: %s", nptr);
}
endptr++;
} else {
mul = suffix_mul(default_suffix, unit);
assert(mul > 0);
}
if (mul == 1) {
/* When a fraction is present, a scale is required. */
if (valf != 0) {
endptr = nptr;
retval = -EINVAL;
goto out;
}
} else {
uint64_t valh, tmp;
/* Compute exact result: 64.64 x 64.0 -> 128.64 fixed point */
mulu64(&val, &valh, val, mul);
mulu64(&valf, &tmp, valf, mul);
val += tmp;
valh += val < tmp;
/* Round 0.5 upward. */
tmp = valf >> 63;
val += tmp;
valh += val < tmp;
/* Report overflow. */
if (valh != 0) {
retval = -ERANGE;
goto out;
}
}
retval = 0;
out:
if (end) {
*end = endptr;
} else if (*endptr) {
retval = -EINVAL;
}
if (retval == 0) {
*result = val;
}
return retval;
}
int qemu_strtosz(const char *nptr, const char **end, uint64_t *result)
{
return do_strtosz(nptr, end, 'B', 1024, result);
}
int qemu_strtosz_MiB(const char *nptr, const char **end, uint64_t *result)
{
return do_strtosz(nptr, end, 'M', 1024, result);
}
int qemu_strtosz_metric(const char *nptr, const char **end, uint64_t *result)
{
return do_strtosz(nptr, end, 'B', 1000, result);
}
/**
* Helper function for error checking after strtol() and the like
*/
static int check_strtox_error(const char *nptr, char *ep,
const char **endptr, bool check_zero,
int libc_errno)
{
assert(ep >= nptr);
/* Windows has a bug in that it fails to parse 0 from "0x" in base 16 */
if (check_zero && ep == nptr && libc_errno == 0) {
char *tmp;
errno = 0;
if (strtol(nptr, &tmp, 10) == 0 && errno == 0 &&
(*tmp == 'x' || *tmp == 'X')) {
ep = tmp;
}
}
if (endptr) {
*endptr = ep;
}
/* Turn "no conversion" into an error */
if (libc_errno == 0 && ep == nptr) {
return -EINVAL;
}
/* Fail when we're expected to consume the string, but didn't */
if (!endptr && *ep) {
return -EINVAL;
}
return -libc_errno;
}
/**
* Convert string @nptr to an integer, and store it in @result.
*
* This is a wrapper around strtol() that is harder to misuse.
* Semantics of @nptr, @endptr, @base match strtol() with differences
* noted below.
*
* @nptr may be null, and no conversion is performed then.
*
* If no conversion is performed, store @nptr in *@endptr and return
* -EINVAL.
*
* If @endptr is null, and the string isn't fully converted, return
* -EINVAL. This is the case when the pointer that would be stored in
* a non-null @endptr points to a character other than '\0'.
*
* If the conversion overflows @result, store INT_MAX in @result,
* and return -ERANGE.
*
* If the conversion underflows @result, store INT_MIN in @result,
* and return -ERANGE.
*
* Else store the converted value in @result, and return zero.
*/
int qemu_strtoi(const char *nptr, const char **endptr, int base,
int *result)
{
char *ep;
long long lresult;
assert((unsigned) base <= 36 && base != 1);
if (!nptr) {
if (endptr) {
*endptr = nptr;
}
return -EINVAL;
}
errno = 0;
lresult = strtoll(nptr, &ep, base);
if (lresult < INT_MIN) {
*result = INT_MIN;
errno = ERANGE;
} else if (lresult > INT_MAX) {
*result = INT_MAX;
errno = ERANGE;
} else {
*result = lresult;
}
return check_strtox_error(nptr, ep, endptr, lresult == 0, errno);
}
/**
* Convert string @nptr to an unsigned integer, and store it in @result.
*
* This is a wrapper around strtoul() that is harder to misuse.
* Semantics of @nptr, @endptr, @base match strtoul() with differences
* noted below.
*
* @nptr may be null, and no conversion is performed then.
*
* If no conversion is performed, store @nptr in *@endptr and return
* -EINVAL.
*
* If @endptr is null, and the string isn't fully converted, return
* -EINVAL. This is the case when the pointer that would be stored in
* a non-null @endptr points to a character other than '\0'.
*
* If the conversion overflows @result, store UINT_MAX in @result,
* and return -ERANGE.
*
* Else store the converted value in @result, and return zero.
*
* Note that a number with a leading minus sign gets converted without
* the minus sign, checked for overflow (see above), then negated (in
* @result's type). This is exactly how strtoul() works.
*/
int qemu_strtoui(const char *nptr, const char **endptr, int base,
unsigned int *result)
{
char *ep;
long long lresult;
assert((unsigned) base <= 36 && base != 1);
if (!nptr) {
if (endptr) {
*endptr = nptr;
}
return -EINVAL;
}
errno = 0;
lresult = strtoull(nptr, &ep, base);
/* Windows returns 1 for negative out-of-range values. */
if (errno == ERANGE) {
*result = -1;
} else {
if (lresult > UINT_MAX) {
*result = UINT_MAX;
errno = ERANGE;
} else if (lresult < INT_MIN) {
*result = UINT_MAX;
errno = ERANGE;
} else {
*result = lresult;
}
}
return check_strtox_error(nptr, ep, endptr, lresult == 0, errno);
}
/**
* Convert string @nptr to a long integer, and store it in @result.
*
* This is a wrapper around strtol() that is harder to misuse.
* Semantics of @nptr, @endptr, @base match strtol() with differences
* noted below.
*
* @nptr may be null, and no conversion is performed then.
*
* If no conversion is performed, store @nptr in *@endptr and return
* -EINVAL.
*
* If @endptr is null, and the string isn't fully converted, return
* -EINVAL. This is the case when the pointer that would be stored in
* a non-null @endptr points to a character other than '\0'.
*
* If the conversion overflows @result, store LONG_MAX in @result,
* and return -ERANGE.
*
* If the conversion underflows @result, store LONG_MIN in @result,
* and return -ERANGE.
*
* Else store the converted value in @result, and return zero.
*/
int qemu_strtol(const char *nptr, const char **endptr, int base,
long *result)
{
char *ep;
assert((unsigned) base <= 36 && base != 1);
if (!nptr) {
if (endptr) {
*endptr = nptr;
}
return -EINVAL;
}
errno = 0;
*result = strtol(nptr, &ep, base);
return check_strtox_error(nptr, ep, endptr, *result == 0, errno);
}
/**
* Convert string @nptr to an unsigned long, and store it in @result.
*
* This is a wrapper around strtoul() that is harder to misuse.
* Semantics of @nptr, @endptr, @base match strtoul() with differences
* noted below.
*
* @nptr may be null, and no conversion is performed then.
*
* If no conversion is performed, store @nptr in *@endptr and return
* -EINVAL.
*
* If @endptr is null, and the string isn't fully converted, return
* -EINVAL. This is the case when the pointer that would be stored in
* a non-null @endptr points to a character other than '\0'.
*
* If the conversion overflows @result, store ULONG_MAX in @result,
* and return -ERANGE.
*
* Else store the converted value in @result, and return zero.
*
* Note that a number with a leading minus sign gets converted without
* the minus sign, checked for overflow (see above), then negated (in
* @result's type). This is exactly how strtoul() works.
*/
int qemu_strtoul(const char *nptr, const char **endptr, int base,
unsigned long *result)
{
char *ep;
assert((unsigned) base <= 36 && base != 1);
if (!nptr) {
if (endptr) {
*endptr = nptr;
}
return -EINVAL;
}
errno = 0;
*result = strtoul(nptr, &ep, base);
/* Windows returns 1 for negative out-of-range values. */
if (errno == ERANGE) {
*result = -1;
}
return check_strtox_error(nptr, ep, endptr, *result == 0, errno);
}
/**
* Convert string @nptr to an int64_t.
*
* Works like qemu_strtol(), except it stores INT64_MAX on overflow,
* and INT64_MIN on underflow.
*/
int qemu_strtoi64(const char *nptr, const char **endptr, int base,
int64_t *result)
{
char *ep;
assert((unsigned) base <= 36 && base != 1);
if (!nptr) {
if (endptr) {
*endptr = nptr;
}
return -EINVAL;
}
/* This assumes int64_t is long long TODO relax */
QEMU_BUILD_BUG_ON(sizeof(int64_t) != sizeof(long long));
errno = 0;
*result = strtoll(nptr, &ep, base);
return check_strtox_error(nptr, ep, endptr, *result == 0, errno);
}
/**
* Convert string @nptr to an uint64_t.
*
* Works like qemu_strtoul(), except it stores UINT64_MAX on overflow.
*/
int qemu_strtou64(const char *nptr, const char **endptr, int base,
uint64_t *result)
{
char *ep;
assert((unsigned) base <= 36 && base != 1);
if (!nptr) {
if (endptr) {
*endptr = nptr;
}
return -EINVAL;
}
/* This assumes uint64_t is unsigned long long TODO relax */
QEMU_BUILD_BUG_ON(sizeof(uint64_t) != sizeof(unsigned long long));
errno = 0;
*result = strtoull(nptr, &ep, base);
/* Windows returns 1 for negative out-of-range values. */
if (errno == ERANGE) {
*result = -1;
}
return check_strtox_error(nptr, ep, endptr, *result == 0, errno);
}
/**
* Convert string @nptr to a double.
*
* This is a wrapper around strtod() that is harder to misuse.
* Semantics of @nptr and @endptr match strtod() with differences
* noted below.
*
* @nptr may be null, and no conversion is performed then.
*
* If no conversion is performed, store @nptr in *@endptr and return
* -EINVAL.
*
* If @endptr is null, and the string isn't fully converted, return
* -EINVAL. This is the case when the pointer that would be stored in
* a non-null @endptr points to a character other than '\0'.
*
* If the conversion overflows, store +/-HUGE_VAL in @result, depending
* on the sign, and return -ERANGE.
*
* If the conversion underflows, store +/-0.0 in @result, depending on the
* sign, and return -ERANGE.
*
* Else store the converted value in @result, and return zero.
*/
int qemu_strtod(const char *nptr, const char **endptr, double *result)
{
char *ep;
if (!nptr) {
if (endptr) {
*endptr = nptr;
}
return -EINVAL;
}
errno = 0;
*result = strtod(nptr, &ep);
return check_strtox_error(nptr, ep, endptr, false, errno);
}
/**
* Convert string @nptr to a finite double.
*
* Works like qemu_strtod(), except that "NaN" and "inf" are rejected
* with -EINVAL and no conversion is performed.
*/
int qemu_strtod_finite(const char *nptr, const char **endptr, double *result)
{
double tmp;
int ret;
ret = qemu_strtod(nptr, endptr, &tmp);
if (!ret && !isfinite(tmp)) {
if (endptr) {
*endptr = nptr;
}
ret = -EINVAL;
}
if (ret != -EINVAL) {
*result = tmp;
}
return ret;
}
/**
* Searches for the first occurrence of 'c' in 's', and returns a pointer
* to the trailing null byte if none was found.
*/
#ifndef HAVE_STRCHRNUL
const char *qemu_strchrnul(const char *s, int c)
{
const char *e = strchr(s, c);
if (!e) {
e = s + strlen(s);
}
return e;
}
#endif
/**
* parse_uint:
*
* @s: String to parse
* @value: Destination for parsed integer value
* @endptr: Destination for pointer to first character not consumed
* @base: integer base, between 2 and 36 inclusive, or 0
*
* Parse unsigned integer
*
* Parsed syntax is like strtoull()'s: arbitrary whitespace, a single optional
* '+' or '-', an optional "0x" if @base is 0 or 16, one or more digits.
*
* If @s is null, or @base is invalid, or @s doesn't start with an
* integer in the syntax above, set *@value to 0, *@endptr to @s, and
* return -EINVAL.
*
* Set *@endptr to point right beyond the parsed integer (even if the integer
* overflows or is negative, all digits will be parsed and *@endptr will
* point right beyond them).
*
* If the integer is negative, set *@value to 0, and return -ERANGE.
*
* If the integer overflows unsigned long long, set *@value to
* ULLONG_MAX, and return -ERANGE.
*
* Else, set *@value to the parsed integer, and return 0.
*/
int parse_uint(const char *s, unsigned long long *value, char **endptr,
int base)
{
int r = 0;
char *endp = (char *)s;
unsigned long long val = 0;
assert((unsigned) base <= 36 && base != 1);
if (!s) {
r = -EINVAL;
goto out;
}
errno = 0;
val = strtoull(s, &endp, base);
if (errno) {
r = -errno;
goto out;
}
if (endp == s) {
r = -EINVAL;
goto out;
}
/* make sure we reject negative numbers: */
while (qemu_isspace(*s)) {
s++;
}
if (*s == '-') {
val = 0;
r = -ERANGE;
goto out;
}
out:
*value = val;
*endptr = endp;
return r;
}
/**
* parse_uint_full:
*
* @s: String to parse
* @value: Destination for parsed integer value
* @base: integer base, between 2 and 36 inclusive, or 0
*
* Parse unsigned integer from entire string
*
* Have the same behavior of parse_uint(), but with an additional check
* for additional data after the parsed number. If extra characters are present
* after the parsed number, the function will return -EINVAL, and *@v will
* be set to 0.
*/
int parse_uint_full(const char *s, unsigned long long *value, int base)
{
char *endp;
int r;
r = parse_uint(s, value, &endp, base);
if (r < 0) {
return r;
}
if (*endp) {
*value = 0;
return -EINVAL;
}
return 0;
}
int qemu_parse_fd(const char *param)
{
long fd;
char *endptr;
errno = 0;
fd = strtol(param, &endptr, 10);
if (param == endptr /* no conversion performed */ ||
errno != 0 /* not representable as long; possibly others */ ||
*endptr != '\0' /* final string not empty */ ||
fd < 0 /* invalid as file descriptor */ ||
fd > INT_MAX /* not representable as int */) {
return -1;
}
return fd;
}
/*
* Implementation of ULEB128 (http://en.wikipedia.org/wiki/LEB128)
* Input is limited to 14-bit numbers
*/
int uleb128_encode_small(uint8_t *out, uint32_t n)
{
g_assert(n <= 0x3fff);
if (n < 0x80) {
*out = n;
return 1;
} else {
*out++ = (n & 0x7f) | 0x80;
*out = n >> 7;
return 2;
}
}
int uleb128_decode_small(const uint8_t *in, uint32_t *n)
{
if (!(*in & 0x80)) {
*n = *in;
return 1;
} else {
*n = *in++ & 0x7f;
/* we exceed 14 bit number */
if (*in & 0x80) {
return -1;
}
*n |= *in << 7;
return 2;
}
}
/*
* helper to parse debug environment variables
*/
int parse_debug_env(const char *name, int max, int initial)
{
char *debug_env = getenv(name);
char *inv = NULL;
long debug;
if (!debug_env) {
return initial;
}
errno = 0;
debug = strtol(debug_env, &inv, 10);
if (inv == debug_env) {
return initial;
}
if (debug < 0 || debug > max || errno != 0) {
warn_report("%s not in [0, %d]", name, max);
return initial;
}
return debug;
}
/*
* Return human readable string for size @val.
* @val can be anything that uint64_t allows (no more than "16 EiB").
* Use IEC binary units like KiB, MiB, and so forth.
* Caller is responsible for passing it to g_free().
*/
char *size_to_str(uint64_t val)
{
static const char *suffixes[] = { "", "Ki", "Mi", "Gi", "Ti", "Pi", "Ei" };
uint64_t div;
int i;
/*
* The exponent (returned in i) minus one gives us
* floor(log2(val * 1024 / 1000). The correction makes us
* switch to the higher power when the integer part is >= 1000.
* (see e41b509d68afb1f for more info)
*/
frexp(val / (1000.0 / 1024.0), &i);
i = (i - 1) / 10;
div = 1ULL << (i * 10);
return g_strdup_printf("%0.3g %sB", (double)val / div, suffixes[i]);
}
char *freq_to_str(uint64_t freq_hz)
{
static const char *const suffixes[] = { "", "K", "M", "G", "T", "P", "E" };
double freq = freq_hz;
size_t idx = 0;
while (freq >= 1000.0) {
freq /= 1000.0;
idx++;
}
assert(idx < ARRAY_SIZE(suffixes));
return g_strdup_printf("%0.3g %sHz", freq, suffixes[idx]);
}
int qemu_pstrcmp0(const char **str1, const char **str2)
{
return g_strcmp0(*str1, *str2);
}
static inline bool starts_with_prefix(const char *dir)
{
size_t prefix_len = strlen(CONFIG_PREFIX);
return !memcmp(dir, CONFIG_PREFIX, prefix_len) &&
(!dir[prefix_len] || G_IS_DIR_SEPARATOR(dir[prefix_len]));
}
/* Return the next path component in dir, and store its length in *p_len. */
static inline const char *next_component(const char *dir, int *p_len)
{
int len;
while ((*dir && G_IS_DIR_SEPARATOR(*dir)) ||
(*dir == '.' && (G_IS_DIR_SEPARATOR(dir[1]) || dir[1] == '\0'))) {
dir++;
}
len = 0;
while (dir[len] && !G_IS_DIR_SEPARATOR(dir[len])) {
len++;
}
*p_len = len;
return dir;
}
char *get_relocated_path(const char *dir)
{
size_t prefix_len = strlen(CONFIG_PREFIX);
const char *bindir = CONFIG_BINDIR;
const char *exec_dir = qemu_get_exec_dir();
GString *result;
int len_dir, len_bindir;
/* Fail if qemu_init_exec_dir was not called. */
assert(exec_dir[0]);
if (!starts_with_prefix(dir) || !starts_with_prefix(bindir)) {
return g_strdup(dir);
}
result = g_string_new(exec_dir);
/* Advance over common components. */
len_dir = len_bindir = prefix_len;
do {
dir += len_dir;
bindir += len_bindir;
dir = next_component(dir, &len_dir);
bindir = next_component(bindir, &len_bindir);
} while (len_dir && len_dir == len_bindir && !memcmp(dir, bindir, len_dir));
/* Ascend from bindir to the common prefix with dir. */
while (len_bindir) {
bindir += len_bindir;
g_string_append(result, "/..");
bindir = next_component(bindir, &len_bindir);
}
if (*dir) {
assert(G_IS_DIR_SEPARATOR(dir[-1]));
g_string_append(result, dir - 1);
}
return g_string_free(result, false);
}
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