/*
 * rdlar.c - new librarian/archiver for RDOFF2.
 * Copyright (c) 2002 RET & COM Research.
 */
 
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <stdarg.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>

#include "rdlar.h"

#define PROGRAM_VERSION "0.1"

/** Types **/
typedef enum { FALSE, TRUE } bool;

/** Constants **/
const char commands[] = "adnrtx";
const char modifiers[] = "cflouvV";

/** Global variables **/
char *progname = "rdlar";
char **_argv = NULL;
struct {
    bool createok;
    bool usefname;
    bool align;
    bool odate;
    bool fresh;
    int verbose;
} options = { 0, 0, 0, 0, 0, 0 };

#define _ENDIANNESS 0		/* 0 for little, 1 for big */


/*
 * Convert long to little endian (if we were compiled on big-endian machine)
 */
static void longtolocal(long * l)
{
#if _ENDIANNESS
    unsigned char t;
    unsigned char * p = (unsigned char *) l;

    t = p[0];
    p[0] = p[3];
    p[3] = t;
    t = p[1];
    p[1] = p[2];
    p[2] = p[1];
#endif
}

/*
 * Print version information
 */
void show_version(void)
{
    puts("New RDOFF2 librarian/archiver, version " PROGRAM_VERSION "\n"
         "Copyright (c) 2002 RET & COM Research.\n"
	 "This program is free software and distributed under GPL (version 2 or later);\n"
	 "see http://www.gnu.org/copyleft/gpl.html for details.");
}


/*
 * Print usage instructions
 */
void usage(void)
{
    printf("Usage:  %s [-]{%s}[%s] libfile [module-name] [files]\n",
	    progname, commands, modifiers);
    puts(" commands:\n"
         "  a            - add module(s) to the library\n"
	 "  d            - delete module(s) from the library\n"
	 "  n            - create the library\n"
	 "  r            - replace module(s)\n"
	 "  t            - display contents of library\n"
	 "  x            - extract module(s)\n"
	 " command specific modifiers:\n"
	 "  o            - preserve original dates\n"
	 "  u            - only replace modules that are newer than library contents\n"
	 " generic modifiers:\n"
 	 "  c            - do not warn if the library had to be created\n"
 	 "  f            - use file name as a module name\n"
	 "  v            - be verbose\n"
	 "  V            - display version information");
}


/*
 * Print an error message and exit
 */
void error_exit(int errcode, bool useperror, const char *fmt, ...)
{
    va_list ap;
    
    fprintf(stderr, "%s: ", progname);
    va_start(ap, fmt);
    vfprintf(stderr, fmt, ap);
    va_end(ap);
    putc('\n', stderr);
    if (useperror) perror(progname);
    exit(errcode);
}


/*
 * Fill in and write a header
 */
void put_header(struct rdlm_hdr *hdr, FILE *libfp, char *modname)
{
    int n = 0;
    
    hdr->hdrsize = sizeof(*hdr);
    if (modname) hdr->hdrsize += (n = strlen(modname) + 1);
    if (libfp == NULL) return;
    if (fwrite(hdr, 1, sizeof(*hdr), libfp) != sizeof(*hdr) ||
         (modname && (fwrite(modname, 1, n, libfp) != n))) 
	error_exit(3, TRUE, "could not write header");
}

/*
 * Copy n bytes from one file to another and return last character read.
 */
char copybytes(FILE *fp, FILE *fp2, int n)
{
    int i, t = 0;

    for (i = 0 ; i < n; i++) {
	t = fgetc(fp);
	if (t == EOF)
	    error_exit(1, FALSE, "premature end of file in '%s'", _argv[2]);
	if (fp2) 
	    if (fputc(t, fp2) == EOF)
		error_exit(1, FALSE, "write error");
    }
    return (char) t;
}


/*
 * Copy unsigned long from one file to another.
 * Return local presentation of long.
 */
long copylong(FILE *fp, FILE *fp2)
{
    long l;
    int i,t;
    unsigned char * p = (unsigned char *) &l;


    for (i = 0 ; i < 4; i++ ) {
	t = fgetc(fp);
	if (t == EOF)
	    error_exit(1, FALSE, "premature end of file in '%s'", _argv[2]);
	if (fp2) 
	    if (fputc(t, fp2) == EOF)
		error_exit(1, FALSE, "write error");
	*p++ = t;
    }
    longtolocal (&l);
    return l;
}


/*
 * Create a new library
 */
int create_library(char *libname)
{
    FILE *libfp;
    struct rdlm_hdr hdr;

    hdr.magic = RDLAMAG;
    hdr.hdrsize = 0;
    hdr.date = time(NULL);
    hdr.owner = getuid();
    hdr.group = getgid();
    hdr.mode = umask(022);
    hdr.size = 0;
    
    libfp = fopen(libname, "wb");
    if (!libfp)
	error_exit(1, TRUE, "could not open '%s'\n", libname);
	    
    /* Write library header */
    put_header(&hdr, libfp, NULL);
    
    fclose(libfp);
    return TRUE;
}


/*
 * Add a module to the library
 */
int add_module(FILE *libfp, const char *fname, char *modname)
{
    FILE *modfp;
    struct rdlm_hdr hdr = { RDLMMAG, 0, 0, 0, 0, 0, 0 };
    struct stat finfo;
    int i;
    
    if (options.verbose)
	fprintf(stderr, "adding module %s\n", modname);

    /* Initialize some fields in the module header */
    if (stat(fname, &finfo) < 0)
    	error_exit(1, TRUE, "could not stat '%s'", fname);
    hdr.date = finfo.st_mtime;
    hdr.owner = finfo.st_uid;
    hdr.group = finfo.st_gid;
    hdr.size = finfo.st_size; 

    modfp = fopen(fname, "rb");
    if (!modfp)
	error_exit(1, TRUE, "could not open '%s'", fname);

    /* Write module header */
    put_header(&hdr, libfp, modname);

    /* Put the module itself */    
    while (! feof(modfp)) {
	i = fgetc(modfp);
	if (i == EOF) break;
        if (fputc(i, libfp) == EOF )
	    error_exit(1, FALSE, "write error");
    }
    
    fclose(modfp);
    return TRUE;
}


/*
 * Main
 */
int main(int argc, char *argv[])
{
    FILE *libfp, *tmpfp, *modfp = NULL;
    struct stat finfo;
    struct rdlm_hdr hdr;
    char buf[MAXMODNAMELEN], *p = NULL;
    char c;
    int i;

    progname = argv[0];
    _argv = argv;
    
    if (argc < 2) {
	usage();
	exit(1);
    }

    /* Check whether some modifiers were specified */
    for (i = 1; i < strlen(argv[1]); i++) {
	switch (c = argv[1][i]) {
	    case 'c':
		options.createok = TRUE;
		break;
	    case 'f':
		options.usefname = TRUE;
		break;
	    case 'l':
		options.align = TRUE;
		break;
	    case 'o':
		options.odate = TRUE;
		break;
	    case 'u':
		options.fresh = TRUE;
		break;
	    case 'v':
		options.verbose++;
		break;
	    case 'V':
		show_version();
		exit(0);
	    default:
		if (strchr(commands, c) == NULL)
		    error_exit(2, FALSE, "invalid command or modifier '%c'", c);
	}
    }
    
    if (argc < 3)
	error_exit(2, FALSE, "missing library name");

    /* Process the command */
    if (argv[1][0] == '-') argv[1]++;
    switch(c = argv[1][0]) {
	case 'a':		/* add a module */
	    if (argc < 4 || (!options.usefname && argc != 5))
		error_exit(2, FALSE, "invalid number of arguments");
	    
	    /* Check if a library already exists. If not - create it */
	    if (access(argv[2], F_OK) < 0) {
		if (!options.createok)
		    fprintf(stderr, "creating library %s\n", argv[2]);
		create_library(argv[2]);
	    }
	    
	    libfp = fopen(argv[2], "ab");
	    if (!libfp)
		error_exit(1, TRUE, "could not open '%s'", argv[2]);
	    
	    if (!options.usefname)
		add_module(libfp, argv[4], argv[3]);
	    else
		for (i = 3; i < argc; i++)
		    add_module(libfp, argv[i], argv[i]);
	    
	    fclose(libfp);
	    break;

	case 'n':		/* create library */
	    create_library(argv[2]);
	    break;

	case 'x':		/* extract module(s) */
	    if (!options.usefname)
		argc--;
	    if (argc < 4)
		error_exit(2, FALSE, "required parameter missing");
	    p = options.usefname ? argv[3] : argv[4];
	case 't':		/* list library contents */
	    libfp = fopen(argv[2],"rb");
	    if (!libfp)
		error_exit(1, TRUE, "could not open '%s'\n", argv[2]);
		
	    /* Read library header */
	    if (fread(&hdr, 1, sizeof(hdr), libfp) != sizeof(hdr) ||
		 hdr.magic != RDLAMAG)
		error_exit(1, FALSE, "invalid library format");

	    /* Walk through the library looking for requested module */
	    while (!feof(libfp)) {
		/* Read module header */
		i = fread(&hdr, 1, sizeof(hdr), libfp);
		if (feof(libfp)) break;
		if (i != sizeof(hdr) || hdr.magic != RDLMMAG)
		    error_exit(1, FALSE, "invalid module header");
		/* Read module name */
		i = hdr.hdrsize - sizeof(hdr);
		if (i > sizeof(buf) || 
		    fread(buf, 1, i, libfp) != i)
		    error_exit(1, FALSE, "invalid module name");
		if (c == 'x') {
		    /* Check against desired name */
		    if (!strcmp(buf, argv[3])) {
			if (options.verbose)
			    fprintf(stderr, "extracting module %s to file %s\n",
				    buf, p);
			modfp = fopen(p, "wb");
			if (!modfp)
			    error_exit(1, TRUE, "could not open '%s'", p);
		    }
		} else {
		    printf("%-40s ", buf);
		    if (options.verbose) {
			printf("%ld bytes", hdr.size);
		    }
		    putchar('\n');
		}
		
		copybytes(libfp, modfp, hdr.size);
		if (modfp) break;
	    }
	    
	    fclose(libfp);
	    if (modfp)
		fclose(modfp);
	    else if (c == 'x')
		error_exit(1, FALSE, "module '%s' not found in '%s'",
			    argv[3], argv[2]);
	    break;

	case 'r':		/* replace module(s) */
	    argc--;
	    if (stat(argv[4], &finfo) < 0)
		error_exit(1, TRUE, "could not stat '%s'", argv[4]);
	case 'd':		/* delete module(s) */
	    if (argc < 4)
		error_exit(2, FALSE, "required parameter missing");
	
	    libfp = fopen(argv[2], "rb");
	    if (!libfp)
		error_exit(1, TRUE, "could not open '%s'", argv[2]);
	    
	    /* Copy the library into a temporary file */
	    tmpfp = tmpfile();
	    if (!tmpfp)
		error_exit(1, TRUE, "could not open temporary file");

	    stat(argv[2], &finfo);
	    copybytes(libfp, tmpfp, finfo.st_size);
	    rewind(tmpfp);
	    freopen(argv[2], "wb", libfp);
	    
	    /* Read library header and write it to a new file */
	    if (fread(&hdr, 1, sizeof(hdr), tmpfp) != sizeof(hdr) ||
		 hdr.magic != RDLAMAG)
		error_exit(1, FALSE, "invalid library format");
	    put_header(&hdr, libfp, NULL);

	    /* Walk through the library looking for requested module */
	    while (!feof(tmpfp)) {
		/* Read module header */
		if (fread(&hdr, 1, sizeof(hdr), tmpfp) != sizeof(hdr) ||
		     hdr.magic != RDLMMAG)
		    error_exit(1, FALSE, "invalid module header");
		/* Read module name */
		i = hdr.hdrsize - sizeof(hdr);
		if (i > sizeof(buf) || 
		    fread(buf, 1, i, tmpfp) != i)
		    error_exit(1, FALSE, "invalid module name");
		/* Check against desired name */
		if (!strcmp(buf, argv[3]) &&
		     (c == 'd' || !options.odate || finfo.st_mtime <= hdr.date)) {
		    if (options.verbose)
			fprintf(stderr, "deleting module %s\n", buf);
		    fseek(tmpfp, hdr.size, SEEK_CUR);
		    break;
		} else {
		    put_header(&hdr, libfp, buf);
		    copybytes(tmpfp, libfp, hdr.size);
		}
	    }
	
	    if (c == 'r') {
		/* Copy new module into library */
		p = options.usefname ? argv[4] : argv[3];
		add_module(libfp, argv[4], p);
	    }
	    
	    /* Copy rest of library if any */
	    while (!feof(tmpfp)) {
		if ((i = fgetc(tmpfp)) == EOF)
		    break;

		if (fputc(i, libfp) == EOF)
		    error_exit(1, FALSE, "write error");
	    }
	    
	    fclose(libfp);
	    fclose(tmpfp);
	    break;
	    
	default:
	    error_exit(2, FALSE, "invalid command '%c'\n", c);
    }
    
    return 0;
}