/*
 * Copyright (C) 1996-2023 The Squid Software Foundation and contributors
 *
 * Squid software is distributed under GPLv2+ license and includes
 * contributions from numerous individuals and organizations.
 * Please see the COPYING and CONTRIBUTORS files for details.
 */

#ifndef _SQUID_COMPAT_SHARED_H
#define _SQUID_COMPAT_SHARED_H

/*
 * This file contains all the compatibility and portability hacks
 * Which are general-case and shared between all OS and support programs.
 *
 * If an OS-specific hack is needed there are per-OS files for that in
 * the os/ sub-directory here.
 *
 * These hacks should be platform and location agnostic.
 * A quick look-over of the code already here should give you an idea
 * of the requirements for wrapping your hack for safe portability.
 */

#ifdef __cplusplus
/*
 * Define an error display handler override.
 * If error_notify is set by the linked program it will be used by the local
 * portability functions. Otherwise perror() will be used.
 */
extern void (*failure_notify) (const char *);
#endif

/*
 * sys/resource.h and sys/time.h are apparently order-dependant.
 */
#if HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#if HAVE_SYS_RESOURCE_H
#include <sys/resource.h>       /* needs sys/time.h above it */
#endif

/*
 * DIRENT functionality can apparently come from many places.
 * With various complaints by different compilers
 */
#if HAVE_DIRENT_H
#include <dirent.h>
#define NAMLEN(dirent) strlen((dirent)->d_name)
#else /* if not HAVE_DIRENT_H */
#define dirent direct
#define NAMLEN(dirent) (dirent)->d_namlen
#if HAVE_SYS_NDIR_H
#include <sys/ndir.h>
#endif /* HAVE_SYS_NDIR_H */
#if HAVE_SYS_DIR_H
#include <sys/dir.h>
#endif /* HAVE_SYS_DIR_H */
#if HAVE_NDIR_H
#include <ndir.h>
#endif /* HAVE_NDIR_H */
#endif /* HAVE_DIRENT_H */

/* The structure dirent also varies between 64-bit and 32-bit environments.
 * Define our own dirent_t type for consistent simple internal use.
 * NP: GCC seems not to care about the type naming differences.
 */
#if defined(__USE_FILE_OFFSET64) && !defined(__GNUC__)
#define dirent_t struct dirent64
#else
#define dirent_t struct dirent
#endif

/*
 * Filedescriptor limits in the different select loops
 *
 * NP: FreeBSD 7 defines FD_SETSIZE as unsigned but Squid needs
 *     it to be signed to compare it with signed values.
 *     Linux and others including FreeBSD <7, define it as signed.
 *     If this causes any issues please contact squid-dev mailing list.
 */
#if defined(USE_SELECT) || defined(USE_SELECT_WIN32)
/* Limited by design */
# define SQUID_MAXFD_LIMIT    ((signed int)FD_SETSIZE)

#elif defined(USE_POLL)
/* Limited due to delay pools */
# define SQUID_MAXFD_LIMIT    ((signed int)FD_SETSIZE)

#elif defined(USE_KQUEUE) || defined(USE_EPOLL) || defined(USE_DEVPOLL)
# define SQUID_FDSET_NOUSE 1

#else
# error Unknown select loop model!
#endif

#if !HAVE_STRUCT_RUSAGE
/**
 * If we don't have getrusage() then we create a fake structure
 * with only the fields Squid cares about.  This just makes the
 * source code cleaner, so we don't need lots of ifdefs in other
 * places
 */
struct rusage {
    struct timeval ru_stime;
    struct timeval ru_utime;
    int ru_maxrss;
    int ru_majflt;
};
#endif /* !HAVE_STRUCT_RUSAGE */

#ifndef min
#ifdef __cplusplus
/**
 * min() comparison may not always be provided.
 * Squid bundles this template for when its needed.
 * May be used on any type which provides operator '<'
 */
template<class A>
inline A const &
min(A const & lhs, A const & rhs)
{
    if (rhs < lhs)
        return rhs;
    return lhs;
}
#else /* !__cplusplus */
/* for non-C++ we are stuck with the < and ? operator */
#define min(a,b) ((a) < (b) ? (a) : (b))
#endif /* __cplusplus */
#endif /* min */

#ifndef max
#ifdef __cplusplus
/**
 * max() comparison may not always be provided.
 * Squid bundles this template for when its needed.
 * May be used on any type which provides operator '>'
 */
template<class A>
inline A const &
max(A const & lhs, A const & rhs)
{
    if (rhs > lhs)
        return rhs;
    return lhs;
}
#else /* !__cplusplus */
/* for non-C++ we are stuck with the < and ? operator */
#define max(a,b) ((a) < (b) ? (b) : (a))
#endif /* __cplusplus */
#endif /* max */

/**
 * Common shared definition of what whitespace consists of for string tests
 */
#define w_space     " \t\n\r"

#ifndef SQUID_NONBLOCK
/* REQUIRED for the below logics. If they move this needs to as well */
#if HAVE_FCNTL_H
#include <fcntl.h>
#endif
#if defined(O_NONBLOCK)
/**
 * We used to assume O_NONBLOCK was broken on Solaris, but evidence
 * now indicates that its fine on Solaris 8, and in fact required for
 * properly detecting EOF on FIFOs.  So now we assume that if
 * its defined, it works correctly on all operating systems.
 */
#define SQUID_NONBLOCK O_NONBLOCK
#else
/** O_NDELAY is our fallback. */
#define SQUID_NONBLOCK O_NDELAY
#endif
#endif

/**
 * Signalling flags are apparently not always provided.
 * TODO find out if these can be moved into specific OS portability files.
 */
#if defined(__cplusplus)
#include <csignal>
#else
#if HAVE_SIGNAL_H
#include <signal.h>
#endif
#endif
#ifndef SA_RESTART
#define SA_RESTART 0
#endif
#ifndef SA_NODEFER
#define SA_NODEFER 0
#endif
#ifndef SA_RESETHAND
#define SA_RESETHAND 0
#endif
#if SA_RESETHAND == 0 && defined(SA_ONESHOT)
#undef SA_RESETHAND
#define SA_RESETHAND SA_ONESHOT
#endif

/**
 * com_err.h is a C header and needs explicit shielding, but not
 * all other system headers including this care to do so.
 */
#ifdef __cplusplus
#if HAVE_ET_COM_ERR_H
extern "C" {
#include <et/com_err.h>
}
#elif HAVE_COM_ERR_H
extern "C" {
#include <com_err.h>
}
#endif
#endif

/*
 * Several function definitions which we provide for security and code safety.
 */
#include "compat/xalloc.h"
#include "compat/xis.h"
#include "compat/xstrerror.h"
#include "compat/xstring.h"
#include "compat/xstrto.h"

/*
 * strtoll() is needed. Squid provides a portable definition.
 */
#include "compat/strtoll.h"

// memrchr() is a GNU extension. MinGW in particular does not define it.
#include "compat/memrchr.h"

#if !HAVE_MEMCPY
#if HAVE_BCOPY
#define memcpy(d,s,n) bcopy((s),(d),(n))
#elif HAVE_MEMMOVE
#define memcpy(d,s,n) memmove((d),(s),(n))
#endif
#endif

#if !HAVE_MEMMOVE && HAVE_BCOPY
#define memmove(d,s,n) bcopy((s),(d),(n))
#endif

/*
 * strnstr() is needed. The OS may not provide a working copy.
 */
#if HAVE_STRNSTR
/* If strnstr exists and is usable we do so. */
#define squid_strnstr(a,b,c)    strnstr(a,b,c)
#else
/* If not we have our own copy imported from FreeBSD */
const char * squid_strnstr(const char *s, const char *find, size_t slen);
#endif

#if __GNUC__
#if !defined(PRINTF_FORMAT_ARG1)
#define PRINTF_FORMAT_ARG1 __attribute__ ((format (printf, 1, 2)))
#endif
#if !defined(PRINTF_FORMAT_ARG2)
#define PRINTF_FORMAT_ARG2 __attribute__ ((format (printf, 2, 3)))
#endif
#if !defined(PRINTF_FORMAT_ARG3)
#define PRINTF_FORMAT_ARG3 __attribute__ ((format (printf, 3, 4)))
#endif
#else /* !__GNU__ */
#define PRINTF_FORMAT_ARG1
#define PRINTF_FORMAT_ARG2
#define PRINTF_FORMAT_ARG3
#endif

#endif /* _SQUID_COMPAT_SHARED_H */