/*
 *  R : A Computer Language for Statistical Data Analysis
 *  Copyright (C) 1995, 1996  Robert Gentleman and Ross Ihaka
 *  Copyright (C) 1997--2019  The R Core Team
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, a copy is available at
 *  https://www.R-project.org/Licenses/
 */

/* <UTF8> char here is handled as a whole string */


/* See system.txt for a description of functions
 */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#define R_USE_SIGNALS 1
#include <Defn.h>

#include <locale.h>

/* necessary for some (older, i.e., ~ <= 1997) Linuxen, and apparently
   also some AIX systems.  NB, included unconditionally later on.
   */
#ifndef FD_SET
# ifdef HAVE_SYS_TIME_H
#  include <sys/time.h>
# endif
#endif

#ifdef HAVE_UNISTD_H
# include <unistd.h>		/* isatty() */
#endif

#include <errno.h>

#include "Fileio.h"

// This creates the interface pointers in this file
#define __SYSTEM__
#define R_INTERFACE_PTRS 1
#include <Rinterface.h>
#undef __SYSTEM__

#include "Runix.h"

attribute_hidden FILE *ifp = NULL; /* used in sys-std.c */

attribute_hidden
Rboolean UsingReadline = TRUE;  /* used in sys-std.c & ../main/platform.c
				   and also in sys-unix.c for tilde expansion */

/* call pointers to allow interface switching */

void R_Suicide(const char *s) { ptr_R_Suicide(s); }
void R_ShowMessage(const char *s) { ptr_R_ShowMessage(s); }
int R_ReadConsole(const char *prompt, unsigned char *buf, int len, int addtohistory)
{ return ptr_R_ReadConsole(prompt, buf, len, addtohistory); }
void R_WriteConsole(const char *buf, int len) {if (ptr_R_WriteConsole) ptr_R_WriteConsole(buf, len); else ptr_R_WriteConsoleEx(buf, len, 0); }
void R_WriteConsoleEx(const char *buf, int len, int otype) {if (ptr_R_WriteConsole) ptr_R_WriteConsole(buf, len); else ptr_R_WriteConsoleEx(buf, len, otype); }
void R_ResetConsole(void) { ptr_R_ResetConsole(); }
#ifndef HAVE_AQUA
void R_FlushConsole(void) { ptr_R_FlushConsole(); }
#endif
void R_ClearerrConsole(void) { ptr_R_ClearerrConsole(); }
void R_Busy(int which) { ptr_R_Busy(which); }
void R_CleanUp(SA_TYPE saveact, int status, int runLast)
{ ptr_R_CleanUp(saveact, status, runLast); }

attribute_hidden
int R_ShowFiles(int nfile, const char **file, const char **headers,
		const char *wtitle, Rboolean del, const char *pager)
{ return ptr_R_ShowFiles(nfile, file, headers, wtitle, del, pager); }

attribute_hidden
int R_ChooseFile(int _new,  char *buf, int len)
{ return ptr_R_ChooseFile(_new, buf, len); }


void R_setStartTime(void); /* in sys-unix.c */


#ifdef HAVE_AQUA
/*  used here and in main/sysutils.c (for system). */
Rboolean useaqua = FALSE;

// Finally in Sep 2012 R.app sets ptr_R_FlushConsole
#include <R_ext/Rdynload.h>
DL_FUNC ptr_do_flushconsole;
void R_FlushConsole(void) {
    if (ptr_R_FlushConsole) ptr_R_FlushConsole(); 
    else if (ptr_do_flushconsole) ptr_do_flushconsole();
}
#endif


void R_setupHistory()
{
    int value, ierr;
    char *p;

    if ((R_HistoryFile = getenv("R_HISTFILE")) == NULL)
	R_HistoryFile = ".Rhistory";
    R_HistorySize = 512;
    if ((p = getenv("R_HISTSIZE"))) {
	value = (int) R_Decode2Long(p, &ierr);
	if (ierr != 0 || value < 0)
	    R_ShowMessage("WARNING: invalid R_HISTSIZE ignored;");
	else
	    R_HistorySize = value;
    }
}

#if defined(HAVE_SYS_RESOURCE_H) && defined(HAVE_GETRLIMIT)
/*
  Needed by AIX and formerly by macOS (but not by POSIX).
  http://www.ibm.com/support/knowledgecenter/ssw_aix_61/com.ibm.aix.basetrf1/getrlimit_64.htm
 */
# ifdef HAVE_SYS_TIME_H
#  include <sys/time.h>
# endif
# include <sys/resource.h>
# ifdef HAVE_LIBC_STACK_END
extern void * __libc_stack_end;
# endif
# ifdef HAVE_KERN_USRSTACK
#  include <unistd.h>
#  include <sys/types.h>
#  include <sys/sysctl.h>
# endif
#endif

int R_running_as_main_program = 0;

/* Protection against embedded misuse, PR#15420 */
static int num_initialized = 0;

static char* unescape_arg(char *p, char* avp) {
    /* Undo the escaping done in the front end */
    char *q;
    for(q = avp; *q; q++) {
	if(*q == '~' && *(q+1) == '+' && *(q+2) == '~') {
	    q += 2;
	    *p++ = ' ';
	} else if(*q == '~' && *(q+1) == 'n' && *(q+2) == '~') {
	    q += 2;
	    *p++ = '\n';
	} else *p++ = *q;
    }
    return p;
}

/* for thr_stksegment */
#if defined(HAVE_THREAD_H)
# include <thread.h>
#endif
#include <signal.h> /* thr_stksegment */

int Rf_initialize_R(int ac, char **av)
{
    int i, ioff = 1, j;
    Rboolean useX11 = TRUE, useTk = FALSE;
    char *p, msg[1024], cmdlines[10000], **avv;
    structRstart rstart;
    Rstart Rp = &rstart;
    Rboolean force_interactive = FALSE;

    if (num_initialized++) {
	fprintf(stderr, "%s", "R is already initialized\n");
	exit(1);
    }


#if defined(HAVE_SYS_RESOURCE_H) && defined(HAVE_GETRLIMIT)
{
    /* getrlimit is POSIX:
       http://pubs.opengroup.org/onlinepubs/9699919799/functions/getrlimit.html
    */
    struct rlimit rlim;

    R_CStackDir = C_STACK_DIRECTION;
    

    if(getrlimit(RLIMIT_STACK, &rlim) == 0) {
	/* 'unlimited' is represented by RLIM_INFINITY, which is a
	   very large (but maybe not the largest) representable value.

	   The standard allows the values RLIM_SAVED_CUR and
	   RLIB_SAVED_MAX, apparently used on 32-bit AIX.  
	   (http://www.ibm.com/support/knowledgecenter/ssw_aix_61/com.ibm.aix.basetrf1/getrlimit_64.htm)

	   These may or may not be different from RLIM_INFINITY (they
	   are the same on Linux and macOS but not Solaris where they
	   are larger).  We will assume that unrepresentable limits
	   are very large.

	   This is cautious: it is extremely unlikely that the soft
	   limit is either unlimited or unrepresentable.
	*/
	rlim_t lim = rlim.rlim_cur;
#if defined(RLIM_SAVED_CUR) && defined(RLIM_SAVED_MAX)
	if (lim == RLIM_SAVED_CUR || lim == RLIM_SAVED_MAX) 
	    lim = RLIM_INFINITY;
#endif
	if (lim != RLIM_INFINITY) R_CStackLimit = (uintptr_t) lim;
    }
#if defined(HAVE_LIBC_STACK_END)
    {
	R_CStackStart = (uintptr_t) __libc_stack_end;
	/* The libc stack end is not exactly at the stack start, so one
	   cannot access __libc_stack_end - R_CStackLimit/getrlimit + 1. We
	   have to find the real stack start that matches getrlimit.

	   A modern alternative to __libc_stack_end and to parsing /proc/maps
	   directly is pthread_getattr_np; it doesn't provide the exact stack
	   start, either, but provides a matching stack size smaller than 
	   the one obtained from getrlimit. However, pthread_getattr_np
	   may have not worked properly on old Linux distributions. */
	
	/* based on GDB relocatable.c */
	FILE *f;
	f = fopen("/proc/self/maps", "r");
	if (f) {
	    for(;;) {
		int c;
		unsigned long start, end;

		if (fscanf(f, "%lx-%lx", &start, &end) == 2 &&
		    R_CStackStart >= (uintptr_t)start &&
		    R_CStackStart < (uintptr_t)end) {
		    
		    /* would this be ok for R_CStackDir == -1? */
		    R_CStackStart = (uintptr_t) ((R_CStackDir == 1) ? end : start);
		    break;
		}
		for(c = getc(f); c != '\n' && c != EOF; c = getc(f));
		if (c == EOF) {
		    /* could also abort here, but R will usually work with
		       R_CStackStart set just for __libc_stack_end */
		    fprintf(stderr, "WARNING: Error parsing /proc/self/maps!\n");
		    break;
		}
	    }
	    fclose(f);
	}
    }
#elif defined(HAVE_KERN_USRSTACK)
    {
	/* Borrowed from mzscheme/gc/os_dep.c */
	int nm[2] = {CTL_KERN, KERN_USRSTACK};
	void * base;
	size_t len = sizeof(void *);
	(void) sysctl(nm, 2, &base, &len, NULL, 0);
	R_CStackStart = (uintptr_t) base;
    }
#elif defined(HAVE_THR_STKSEGMENT)
    {
	/* Solaris */
	stack_t stack;
	if (thr_stksegment(&stack))
	    R_Suicide("Cannot obtain stack information (thr_stksegment).");
	R_CStackStart = (uintptr_t) stack.ss_sp;
	/* This _may_ have to be adjusted for a (perhaps theoretical) platform
	   where the stack would grow upwards.

	   The stack size could be updated based on stack.ss_size, but experiments
	   suggest getrlimit is safe here. */
    }
#else
    if(R_running_as_main_program) {
	/* This is not the main program, but unless embedded it is
	   near the top, 5540 bytes away when checked. */
	R_CStackStart = (uintptr_t) &i + (6000 * R_CStackDir);
    }
#endif
    if(R_CStackStart == (uintptr_t)(-1)) R_CStackLimit = (uintptr_t)(-1); /* never set */

    /* setup_Rmainloop includes (disabled) code to test stack detection */
}
#endif

    ptr_R_Suicide = Rstd_Suicide;
    ptr_R_ShowMessage = Rstd_ShowMessage;
    ptr_R_ReadConsole = Rstd_ReadConsole;
    ptr_R_WriteConsole = Rstd_WriteConsole;
    ptr_R_ResetConsole = Rstd_ResetConsole;
    ptr_R_FlushConsole = Rstd_FlushConsole;
    ptr_R_ClearerrConsole = Rstd_ClearerrConsole;
    ptr_R_Busy = Rstd_Busy;
    ptr_R_CleanUp = Rstd_CleanUp;
    ptr_R_ShowFiles = Rstd_ShowFiles;
    ptr_R_ChooseFile = Rstd_ChooseFile;
    ptr_R_loadhistory = Rstd_loadhistory;
    ptr_R_savehistory = Rstd_savehistory;
    ptr_R_addhistory = Rstd_addhistory;
    ptr_R_EditFile = NULL; /* for future expansion */
    R_timeout_handler = NULL;
    R_timeout_val = 0;

    R_GlobalContext = NULL; /* Make R_Suicide less messy... */

    if((R_Home = R_HomeDir()) == NULL)
	R_Suicide("R home directory is not defined");
    BindDomain(R_Home);

    process_system_Renviron();

    R_setStartTime();
    R_DefParams(Rp);
    /* Store the command line arguments before they are processed
       by the R option handler.
     */
    R_set_command_line_arguments(ac, av);
    cmdlines[0] = '\0';

    /* first task is to select the GUI.
       If run from the shell script, only Tk|tk|X11|x11 are allowed.
     */
    for(i = 0, avv = av; i < ac; i++, avv++) {
	if (!strcmp(*avv, "--args"))
	    break;
	if(!strncmp(*avv, "--gui", 5) || !strncmp(*avv, "-g", 2)) {
	    if(!strncmp(*avv, "--gui", 5) && strlen(*avv) >= 7)
		p = &(*avv)[6];
	    else {
		if(i+1 < ac) {
		    avv++; p = *avv; ioff++;
		} else {
		    snprintf(msg, 1024,
			    _("WARNING: --gui or -g without value ignored"));
		    R_ShowMessage(msg);
		    p = "X11";
		}
	    }
	    if(!strcmp(p, "none"))
		useX11 = FALSE; // not allowed from R.sh
#ifdef HAVE_AQUA
	    else if(!strcmp(p, "aqua"))
		useaqua = TRUE; // not allowed from R.sh but used by R.app
#endif
	    else if(!strcmp(p, "X11") || !strcmp(p, "x11"))
		useX11 = TRUE;
	    else if(!strcmp(p, "Tk") || !strcmp(p, "tk"))
		useTk = TRUE;
	    else {
#ifdef HAVE_X11
		snprintf(msg, 1024,
			 _("WARNING: unknown gui '%s', using X11\n"), p);
#else
		snprintf(msg, 1024,
			 _("WARNING: unknown gui '%s', using none\n"), p);
#endif
		R_ShowMessage(msg);
	    }
	    /* now remove it/them */
	    for(j = i; j < ac - ioff; j++)
		av[j] = av[j + ioff];
	    ac -= ioff;
	    break;
	}
    }

#ifdef HAVE_X11
    if(useX11) R_GUIType = "X11";
#endif /* HAVE_X11 */

#ifdef HAVE_AQUA
    if(useaqua) R_GUIType = "AQUA";
#endif

#ifdef HAVE_TCLTK
    if(useTk) R_GUIType = "Tk";
#endif

    R_common_command_line(&ac, av, Rp);
    while (--ac) {
	if (**++av == '-') {
	    if(!strcmp(*av, "--no-readline")) {
		UsingReadline = FALSE;
	    } else if(!strcmp(*av, "-f")) {
		ac--; av++;
#define R_INIT_TREAT_F(_AV_)						\
		Rp->R_Interactive = FALSE;				\
		if(strcmp(_AV_, "-")) {					\
		    char path[PATH_MAX], *p = path;			\
		    p = unescape_arg(p, _AV_);				\
		    *p = '\0';						\
		    ifp = R_fopen(path, "r");				\
		    if(!ifp) {						\
			snprintf(msg, 1024,				\
				 _("cannot open file '%s': %s"),	\
				 path, strerror(errno));		\
			R_Suicide(msg);					\
		    }							\
		}
		R_INIT_TREAT_F(*av);

	    } else if(!strncmp(*av, "--file=", 7)) {

		R_INIT_TREAT_F((*av)+7);

	    } else if(!strcmp(*av, "-e")) {
		ac--; av++;
		Rp->R_Interactive = FALSE;
		if(strlen(cmdlines) + strlen(*av) + 2 <= 10000) {
		    char *p = cmdlines+strlen(cmdlines);
		    p = unescape_arg(p, *av);
		    *p++ = '\n'; *p = '\0';
		} else {
		    snprintf(msg, 1024, _("WARNING: '-e %s' omitted as input is too long\n"), *av);
		    R_ShowMessage(msg);
		}
	    } else if(!strcmp(*av, "--args")) {
		break;
	    } else if(!strcmp(*av, "--interactive")) {
		force_interactive = TRUE;
		break;
	    } else {
#ifdef HAVE_AQUA
		// r27492: in 2003 launching from 'Finder OSX' passed this
		if(!strncmp(*av, "-psn", 4)) break; else
#endif
		snprintf(msg, 1024, _("WARNING: unknown option '%s'\n"), *av);
		R_ShowMessage(msg);
	    }
	} else {
	    snprintf(msg, 1024, _("ARGUMENT '%s' __ignored__\n"), *av);
	    R_ShowMessage(msg);
	}
    }

    if(strlen(cmdlines)) { /* had at least one -e option */
	size_t res;
	if(ifp) R_Suicide(_("cannot use -e with -f or --file"));
	ifp = tmpfile();
	if(!ifp) R_Suicide(_("creating temporary file for '-e' failed"));
	res = fwrite(cmdlines, strlen(cmdlines)+1, 1, ifp);
	if(res != 1) error("fwrite error in initialize_R");
	fflush(ifp);
	rewind(ifp);
    }
    if (ifp && Rp->SaveAction != SA_SAVE) Rp->SaveAction = SA_NOSAVE;

    R_SetParams(Rp);

    if(!Rp->NoRenviron) {
	process_site_Renviron();
	process_user_Renviron();

	/* allow for R_MAX_[VN]SIZE and R_[VN]SIZE in user/site Renviron */
	R_SizeFromEnv(Rp);
	R_SetParams(Rp);
    }


    /* On Unix the console is a file; we just use stdio to write on it */

#ifdef HAVE_AQUA
    if(useaqua)
	R_Interactive = useaqua;
    else
#endif
	R_Interactive = R_Interactive && (force_interactive || isatty(0));

#ifdef HAVE_AQUA
    /* for Aqua and non-dumb terminal use callbacks instead of connections
       and pretty-print warnings/errors (ESS = dumb terminal) */
    if(useaqua || 
       (R_Interactive && getenv("TERM") && strcmp(getenv("TERM"), "dumb"))) {
	R_Outputfile = NULL;
	R_Consolefile = NULL;
	ptr_R_WriteConsoleEx = Rstd_WriteConsoleEx;
	ptr_R_WriteConsole = NULL;
    } else {
#endif
	R_Outputfile = stdout;
	R_Consolefile = stderr;
#ifdef HAVE_AQUA
    }
#endif


/*
 *  Since users' expectations for save/no-save will differ, we decided
 *  that they should be forced to specify in the non-interactive case.
 */
    if (!R_Interactive && Rp->SaveAction != SA_SAVE &&
	Rp->SaveAction != SA_NOSAVE)
	R_Suicide(_("you must specify '--save', '--no-save' or '--vanilla'"));

    R_setupHistory();
    if (R_RestoreHistory)
	Rstd_read_history(R_HistoryFile);
    fpu_setup(1);

    return(0);
}

    /*
       This function can be used to open the named files in text
       editors.  If the file does not exist then the editor should be
       opened to create a new file.  On GUI platforms multiple files
       can be opened in separate editor windows, but this currently
       only works on Windows and Aqua.
    */

    /*
     *     nfile   = number of files
     *     file    = array of filenames
     *     editor  = editor to be used.
     */
int R_EditFiles(int nfile, const char **file, const char **title,
		const char *editor)
{
    char  buf[1024];

    if (ptr_R_EditFiles) return(ptr_R_EditFiles(nfile, file, title, editor));

    if (nfile > 0) {
	if (nfile > 1)
	    R_ShowMessage(_("WARNING: Only editing the first in the list of files"));

	if (ptr_R_EditFile) ptr_R_EditFile((char *) file[0]);
	else {
	    /* Quote path if necessary */
	    if (editor[0] != '"' && Rf_strchr(editor, ' '))
		snprintf(buf, 1024, "\"%s\" \"%s\"", editor, file[0]);
	    else
		snprintf(buf, 1024, "%s \"%s\"", editor, file[0]);
	    if (R_system(buf) == 127)
		warningcall(R_NilValue, _("error in running command"));
	}
	return 0;
    }
    return 1;
}

/* Returns the limit on the number of open files. On error or when no
   limit is known, returns a negative number. */
int R_GetFDLimit() {

#if defined(HAVE_SYS_RESOURCE_H) && defined(HAVE_GETRLIMIT)
    struct rlimit rlim;
    /* Historically this was RLIMIT_OFILE on BSD, but we require the
       POSIX version.

       Most often RLIM_INFINITY >= INT_MAX, but not on some 32-bit
       systems.  On all current systems the limit will be at most a
       few thousand.

       Note that 'unlimited' here probably does not mean it:
       e.g. there is a kernel limit of OPEN_MAX on macOS.
    */
    if (getrlimit(RLIMIT_NOFILE, &rlim) == 0) {
	rlim_t lim = rlim.rlim_cur;
#if defined(RLIM_SAVED_CUR) && defined(RLIM_SAVED_MAX)
	if (lim == RLIM_SAVED_CUR || lim == RLIM_SAVED_MAX) 
	    lim = RLIM_INFINITY;
#endif
	return (int)((lim > INT_MAX) ? INT_MAX : lim);
    }
#endif
    return -1;
}

/* Tries to ensure that the limit on the number of open files is at least
   as desired. Returns 'desired' if successful, otherwise a smaller positive
   number giving the current limit. On error (no limit known), a negative
   number is returned. */
int R_EnsureFDLimit(int desired) {

#if defined(HAVE_SYS_RESOURCE_H) && defined(HAVE_SETRLIMIT) && defined(HAVE_GETRLIMIT)
    struct rlimit rlim;
    if (getrlimit(RLIMIT_NOFILE, &rlim))
	return -1;
    rlim_t lim = rlim.rlim_cur;
#if defined(RLIM_SAVED_CUR) && defined(RLIM_SAVED_MAX)
    if (lim == RLIM_SAVED_CUR || lim == RLIM_SAVED_MAX) 
	lim = RLIM_INFINITY;
#endif
    if (lim == RLIM_INFINITY || lim >= desired)
	return desired;

    /* increase the limit */
    rlim_t hlim = rlim.rlim_max;
#if defined(RLIM_SAVED_CUR) && defined(RLIM_SAVED_MAX)
    if (hlim == RLIM_SAVED_CUR || hlim == RLIM_SAVED_MAX) 
	hlim = RLIM_INFINITY;
#endif
    if (hlim == RLIM_INFINITY || hlim >= desired)
	rlim.rlim_cur = (rlim_t) desired;
    else
	rlim.rlim_cur = hlim;
    if (setrlimit(RLIMIT_NOFILE, &rlim))
	return (int) lim; /* also could return error */
    
    return (int) rlim.rlim_cur;
#else
    return -1;
#endif
}