src/lib/compat.c

/* Copyright (c) 2002-2018 Dovecot authors, see the included COPYING file */

#include "config.h"
#undef HAVE_CONFIG_H

/* Linux needs the _XOPEN_SOURCE define, but others don't. It needs to be
   defined before unistd.h, so we need the above config.h include hack.. */
#ifdef PREAD_WRAPPERS
#  define _XOPEN_SOURCE 500 /* Linux */
#endif

#define IN_COMPAT_C
#include "lib.h"

#include <stdio.h>
#include <ctype.h>
#include <unistd.h>
#include <syslog.h>
#include <time.h>
#include <sys/time.h>

#ifndef INADDR_NONE
#  define INADDR_NONE INADDR_BROADCAST
#endif

#if !defined (HAVE_STRCASECMP) && !defined (HAVE_STRICMP)
int i_my_strcasecmp(const char *s1, const char *s2)
{
    while (*s1 != '\0' && i_toupper(*s1) == i_toupper(*s2)) {
        s1++; s2++;
    }

        return i_toupper(*s1) - i_toupper(*s2);
}

int i_my_strncasecmp(const char *s1, const char *s2, size_t max_chars)
{
    while (max_chars > 1 && *s1 != '\0' &&
           i_toupper(*s1) == i_toupper(*s2)) {
        s1++; s2++; max_chars--;
    }

        return i_toupper(*s1) - i_toupper(*s2);
}
#endif

#ifndef HAVE_INET_ATON
int i_my_inet_aton(const char *cp, struct in_addr *inp)
{
    in_addr_t addr;

    addr = inet_addr(cp);
    if (addr == INADDR_NONE)
        return 0;

    inp->s_addr = addr;
        return 1;
}
#endif

#ifndef HAVE_VSYSLOG
void i_my_vsyslog(int priority, const char *format, va_list args)
{
    T_BEGIN {
        syslog(priority, "%s", t_strdup_vprintf(format, args));
    } T_END;
}
#endif

#ifndef HAVE_GETPAGESIZE
int i_my_getpagesize(void)
{
#ifdef _SC_PAGESIZE
    return sysconf(_SC_PAGESIZE);
#else
#  ifdef __GNUC__
#    warning Guessing page size to be 4096
#  endif
    return 4096;
#endif
}
#endif

#ifndef HAVE_WRITEV
ssize_t i_my_writev(int fd, const struct iovec *iov, int iov_len)
{
    size_t written;
    ssize_t ret;
    int i;

    written = 0;
    for (i = 0; i < iov_len; i++, iov++) {
        ret = write(fd, iov->iov_base, iov->iov_len);
        if (ret < 0)
            return -1;

        written += ret;
        if ((size_t)ret != iov->iov_len)
            break;
    }

    if (written > SSIZE_T_MAX) {
        errno = ERANGE;
        return -1;
    }

    return (ssize_t)written;
}
#endif

#if !defined(HAVE_PREAD) || defined(PREAD_BROKEN)
ssize_t i_my_pread(int fd, void *buf, size_t count, off_t offset)
{
    ssize_t ret;
    off_t old_offset;

    old_offset = lseek(fd, 0, SEEK_CUR);
    if (old_offset == -1)
        return -1;

    if (lseek(fd, offset, SEEK_SET) < 0)
        return -1;

    ret = read(fd, buf, count);
    if (ret < 0)
        return -1;

    if (lseek(fd, old_offset, SEEK_SET) < 0)
        return -1;
    return ret;
}

ssize_t i_my_pwrite(int fd, const void *buf, size_t count, off_t offset)
{
    ssize_t ret;
    off_t old_offset;

    old_offset = lseek(fd, 0, SEEK_CUR);
    if (old_offset == -1)
        return -1;

    if (lseek(fd, offset, SEEK_SET) < 0)
        return -1;

    ret = write(fd, buf, count);
    if (ret < 0)
        return -1;

    if (lseek(fd, old_offset, SEEK_SET) < 0)
        return -1;
    return ret;
}
#elif defined(PREAD_WRAPPERS)

ssize_t i_my_pread(int fd, void *buf, size_t count, off_t offset)
{
    ssize_t ret;

    ret = pread(fd, buf, count, offset);
    return ret;
}

ssize_t i_my_pwrite(int fd, const void *buf, size_t count, off_t offset)
{
    return pwrite(fd, buf, count, offset);
}
#endif

#ifndef HAVE_SETEUID
int i_my_seteuid(uid_t euid)
{
#ifdef HAVE_SETREUID
    /* HP-UX at least doesn't have seteuid() but has setreuid() */
    return setreuid(-1, euid);
#else
#  error Missing seteuid functionality
#endif
}
#endif

#ifndef HAVE_SETEGID
int i_my_setegid(gid_t egid)
{
#ifdef HAVE_SETRESGID
    /* HP-UX at least doesn't have setegid() but has setresgid() */
    return setresgid(-1, egid, -1);
#else
#  error Missing setegid functionality
#endif
}
#endif

#ifndef HAVE_LIBGEN_H
char *i_my_basename(char *path)
{
    char *p;

    /* note that this isn't POSIX-compliant basename() replacement.
       too much trouble without any gain. */
    p = strrchr(path, '/');
    return p == NULL ? path : p + 1;
}
#endif

#ifdef HAVE_OLD_VSNPRINTF
#undef vsnprintf
int i_my_vsnprintf(char *str, size_t size, const char *format, va_list ap)
{
    size_t tmp_size;
    char *tmp;
    int ret;

    /* On overflow HP-UX returns -1, IRIX and Tru64 return size-1. */
    ret = vsnprintf(str, size, format, ap);
    if (ret >= 0 && (size_t)ret+1 != size)
        return ret;

    /* see if data stack has enough available space for it */
    tmp_size = t_get_bytes_available();
    if (tmp_size > size) {
        tmp = t_buffer_get(tmp_size);
        ret = vsnprintf(tmp, tmp_size, format, ap);
        if (ret >= 0 && (size_t)ret+1 != tmp_size) {
            if (size > 0) {
                memcpy(str, tmp, size-1);
                str[size-1] = '\0';
            }
            return ret;
        }
    } else {
        tmp_size = size;
    }

    /* try to allocate enough memory to get it to fit. */
    do {
        tmp_size = nearest_power(tmp_size+1);
        tmp = i_malloc(tmp_size);
        ret = vsnprintf(tmp, tmp_size, format, ap);
        if (ret >= 0 && (size_t)ret+1 != tmp_size) {
            if (size > 0) {
                memcpy(str, tmp, size-1);
                str[size-1] = '\0';
            }
            i_free(tmp);
            return ret;
        }
        i_free(tmp);
    } while (tmp_size < 1024*1024);

    i_panic("my_vsnprintf(): Output string too big");
}
#endif

#ifndef HAVE_CLOCK_GETTIME
int i_my_clock_gettime(int clk_id, struct timespec *tp)
{
    struct timeval tv;

    i_assert(clk_id == CLOCK_REALTIME);

    /* fallback to using microseconds */
    if (gettimeofday(&tv, NULL) < 0)
        return -1;
    tp->tv_sec = tv.tv_sec;
    tp->tv_nsec = tv.tv_usec * 1000;
    return 0;
}
#endif