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#define _GNU_SOURCE
#include <errno.h>
#include <stdio.h>
#include <syslog.h>
#include <string.h>
#include <stdarg.h>
#include <stdlib.h>
#include "cgen.h"
#include "buf.h"
#include "config/debug.h"
int write_buf(char** buf, size_t * buflen, const char* val)
{
/* write_buf will not write outside of (*buf)[0..(*buflen-1)]
* if *buflen > strlen(val), then write_buf will ensure that *buf points to a null-terminated string.
* on success, write_buf will advance *buf to the next free char,
* set *buflen to indicate the quantity of remaining space,
* and return 0.
* on error, write_buf will set errno, return 1, and will not modify *buf or *buflen.
* *buf and val should not overlap.
*/
LET(size_t copy_amt = strlen(val) + 1, copy_amt == 0,
"Integer overflow.", out_err_overflow);
if (*buflen < copy_amt)
goto out_err_range;
memcpy(*buf, val, copy_amt);
*buf += copy_amt;
*buflen -= copy_amt;
return 0;
out_err_overflow:
errno = EOVERFLOW;
return 1;
out_err_range:
errno = ERANGE;
return 1;
}
int format_buf(char** buf, size_t* buflen, const char* fmt, ...)
{
/* format_buf will not write outside of (*buf)[0..(*buflen-1)]
* if *buflen > 0, format_buf will ensure that *buf points to a null-terminated string.
* on success, format_buf will advance *buf to the next free char,
* set *buflen to indicate the quantity of remaining space,
* and return 0.
* on error, format_buf will set errno, return 1, and will not modify *buf or *buflen.
* *buf should not overlap with fmt or any optional arguments.
*/
if (*buflen < 1)
{
errno = ERANGE;
return 1;
}
va_list ap;
va_start(ap, fmt);
int status = vsnprintf(*buf, *buflen, fmt, ap);
int err = errno;
va_end(ap);
if (status < 0)
goto out_err;
size_t written = (size_t) status;
err = ERANGE;
if (written >= *buflen)
goto out_err;
err = EOVERFLOW;
LET(written = written + 1, written == 0,
"Integer overflow.", out_err);
*buf += written;
*buflen -= written;
return 0;
out_err:
(*buf)[*buflen-1] = '\0';
errno = err;
return 1;
}
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