/*
 * dpkg-deb - construction and deconstruction of *.deb archives
 * extract.c - extracting archives
 *
 * Copyright (C) 1994,1995 Ian Jackson <iwj10@cus.cam.ac.uk>
 *
 * This 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,
 * or (at your option) any later version.
 *
 * This 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 dpkg; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <signal.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <errno.h>
#include <unistd.h>
#include <dirent.h>
#include <limits.h>
#include <ctype.h>
#include <assert.h>
#include <ar.h>

#include "config.h"
#include "dpkg.h"
#include "dpkg-deb.h"
#include "myopt.h"

static void movecontrolfiles(const char *thing) {
  char buf[200];
  pid_t c1;
  
  sprintf(buf, "mv %s/* . && rmdir %s", thing, thing);
  if (!(c1= m_fork())) {
    execlp("sh","sh","-c",buf,(char*)0); ohshite("failed to exec sh -c mv foo/* &c");
  }
  waitsubproc(c1,"sh -c mv foo/* &c",0);
}

static void readfail(FILE *a, const char *filename, const char *what) {
  if (ferror(a)) {
    ohshite("error reading %s from %.255s",what,filename);
  } else {
    ohshit("unexpected end of file in %s in %.255s",what,filename);
  }
}

static unsigned long parseheaderlength(const char *inh, size_t len,
                                       const char *fn, const char *what) {
  char lintbuf[15];
  unsigned long r;
  char *endp;

  if (memchr(inh,0,len))
    ohshit("file `%.250s' is corrupt - %.250s length contains nulls",fn,what);
  assert(sizeof(lintbuf) > len);
  memcpy(lintbuf,inh,len);
  lintbuf[len]= ' ';
  *strchr(lintbuf,' ')= 0;
  r= strtoul(lintbuf,&endp,10);
  if (*endp)
    ohshit("file `%.250s' is corrupt - bad digit (code %d) in %s",fn,*endp,what);
  return r;
}

static void skipmember(FILE *ar, const char *fn, long memberlen) {
  int c;
  
  memberlen += (memberlen&1);
  while (memberlen > 0) {
    if ((c= getc(ar)) == EOF) readfail(ar,fn,"skipped member data");
    memberlen--;
  }
}

void extracthalf(const char *debar, const char *directory,
                 const char *taroption, int admininfo) {
  char versionbuf[40];
  float versionnum;
  char ctrllenbuf[40], *infobuf;
  long ctrllennum, memberlen= 0;
  int dummy, l= 0;
  pid_t c1=0,c2,c3;
  unsigned char *ctrlarea= 0;
  int p1[2], p2[2];
  FILE *ar, *pi;
  struct stat stab;
  char nlc;
  char *cur;
  struct ar_hdr arh;
  int readfromfd, oldformat, header_done, adminmember, c;
  
  ar= fopen(debar,"r"); if (!ar) ohshite("failed to read archive `%.255s'",debar);
  if (fstat(fileno(ar),&stab)) ohshite("failed to fstat archive");
  if (!fgets(versionbuf,sizeof(versionbuf),ar)) readfail(ar,debar,"version number");

  if (!strcmp(versionbuf,"!<arch>\n")) {
    oldformat= 0;

    ctrllennum= 0;
    header_done= 0;
    for (;;) {
      if (fread(&arh,1,sizeof(arh),ar) != sizeof(arh))
        readfail(ar,debar,"between members");
      if (memcmp(arh.ar_fmag,ARFMAG,sizeof(arh.ar_fmag)))
        ohshit("file `%.250s' is corrupt - bad magic at end of first header",debar);
      memberlen= parseheaderlength(arh.ar_size,sizeof(arh.ar_size),
                                   debar,"member length");
      if (memberlen<0)
        ohshit("file `%.250s' is corrupt - negative member length %ld",debar,memberlen);
      if (!header_done) {
        if (memcmp(arh.ar_name,"debian-binary   ",sizeof(arh.ar_name)))
          ohshit("file `%.250s' is not a debian binary archive (try dpkg-split?)",debar);
        infobuf= m_malloc(memberlen+1);
        if (fread(infobuf,1, memberlen + (memberlen&1), ar) != memberlen + (memberlen&1))
          readfail(ar,debar,"header info member");
        infobuf[memberlen]= 0;
        cur= strchr(infobuf,'\n');
        if (!cur) ohshit("archive has no newlines in header");
        *cur= 0;
        cur= strchr(infobuf,'.');
        if (!cur) ohshit("archive has no dot in version number");
        *cur= 0;
        if (strcmp(infobuf,"2"))
          ohshit("archive version %.250s not understood, get newer " BACKEND, infobuf);
        *cur= '.';
        strncpy(versionbuf,infobuf,sizeof(versionbuf));
        versionbuf[sizeof(versionbuf)-1]= 0;
        header_done= 1;
      } else if (arh.ar_name[0] == '_') {
          /* Members with `_' are noncritical, and if we don't understand them
           * we skip them.
           */
        skipmember(ar,debar,memberlen);
      } else {
        adminmember=
          !memcmp(arh.ar_name,ADMINMEMBER,sizeof(arh.ar_name)) ? 1 :
          !memcmp(arh.ar_name,DATAMEMBER,sizeof(arh.ar_name)) ? 0 :
          -1;
        if (adminmember == -1) {
          ohshit("file `%.250s' contains ununderstood data member %.*s, giving up",
                 debar, (int)sizeof(arh.ar_name), arh.ar_name);
        }
        if (adminmember == 1) {
          if (ctrllennum != 0)
            ohshit("file `%.250s' contains two control members, giving up", debar);
          ctrllennum= memberlen;
        }
        if (!adminmember != !admininfo) {
          skipmember(ar,debar,memberlen);
        } else {
          break; /* Yes ! - found it. */
        }
      }
    }

    if (admininfo >= 2)
      if (printf(" new debian package, version %s.\n"
                 " size %ld bytes: control archive= %ld bytes.\n",
                 versionbuf, (long)stab.st_size, ctrllennum) == EOF ||
          fflush(stdout)) werr("stdout");
    
  } else if (!strncmp(versionbuf,"0.93",4) &&
             sscanf(versionbuf,"%f%c%d",&versionnum,&nlc,&dummy) == 2 &&
             nlc == '\n') {
    
    oldformat= 1;
    l= strlen(versionbuf); if (l && versionbuf[l-1]=='\n') versionbuf[l-1]=0;
    if (!fgets(ctrllenbuf,sizeof(ctrllenbuf),ar))
      readfail(ar,debar,"ctrl information length");
    if (sscanf(ctrllenbuf,"%ld%c%d",&ctrllennum,&nlc,&dummy) !=2 || nlc != '\n')
      ohshit("archive has malformatted ctrl len `%s'",ctrllenbuf);

    if (admininfo >= 2)
      if (printf(" old debian package, version %s.\n"
                 " size %ld bytes: control archive= %ld, main archive= %ld.\n",
                 versionbuf, (long)stab.st_size, ctrllennum,
                 (long) (stab.st_size - ctrllennum - strlen(ctrllenbuf) - l)) == EOF ||
          fflush(stdout)) werr("stdout");
    
    ctrlarea= malloc(ctrllennum); if (!ctrlarea) ohshite("malloc ctrlarea failed");

    errno=0; if (fread(ctrlarea,1,ctrllennum,ar) != ctrllennum)
      readfail(ar,debar,"ctrlarea");

  } else {
    
    if (!strncmp(versionbuf,"!<arch>",7)) {
      if (fprintf(stderr, BACKEND
                  ": file looks like it might be an archive which has been\n"
                  BACKEND ":    corrupted by being downloaded in ASCII mode\n")
          == EOF) werr("stderr");
    }

    ohshit("`%.255s' is not a debian format archive",debar);

  }

  fflush(ar);
  if (oldformat) {
    if (admininfo) {
      m_pipe(p1);
      if (!(c1= m_fork())) {
        close(p1[0]);
        if (!(pi= fdopen(p1[1],"w"))) ohshite("failed to fdopen p1 in paste");
        errno=0; if (fwrite(ctrlarea,1,ctrllennum,pi) != ctrllennum)
          ohshit("failed to write to gzip -dc");
        if (fclose(pi)) ohshit("failed to close gzip -dc");
        exit(0);
      }
      close(p1[1]);
      readfromfd= p1[0];
    } else {
      if (lseek(fileno(ar),l+strlen(ctrllenbuf)+ctrllennum,SEEK_SET) == -1)
        ohshite("failed to syscall lseek to files archive portion");
      c1= -1;
      readfromfd= fileno(ar);
    }
  } else {
    m_pipe(p1);
    if (!(c1= m_fork())) {
      close(p1[0]);
      if (!(pi= fdopen(p1[1],"w"))) ohshite("failed to fdopen p1 in copy");
      while (memberlen > 0) {
        if ((c= getc(ar)) == EOF) readfail(ar,debar,"member data");
        if (putc(c,pi) == EOF) ohshite("failed to write to pipe in copy");
        memberlen--;
      }
      if (fclose(pi) == EOF) ohshite("failed to close pipe in copy");
      exit(0);
    }
    close(p1[1]);
    readfromfd= p1[0];
  }
  
  if (taroption) m_pipe(p2);
  
  if (!(c2= m_fork())) {
    m_dup2(readfromfd,0);
    if (admininfo) close(p1[0]);
    if (taroption) { m_dup2(p2[1],1); close(p2[0]); close(p2[1]); }
    execlp(GZIP,"gzip","-dc",(char*)0); ohshite("failed to exec gzip -dc");
  }
  if (readfromfd != fileno(ar)) close(readfromfd);
  close(p2[1]);

  if (taroption && directory) {
    if (chdir(directory)) {
      if (errno == ENOENT) {
        if (mkdir(directory,0777)) ohshite("failed to create directory");
        if (chdir(directory)) ohshite("failed to chdir to directory after creating it");
      } else {
        ohshite("failed to chdir to directory");
      }
    }
  }

  if (taroption) {
    if (!(c3= m_fork())) {
      char buffer[30+2];
      if(strlen(taroption) > 30) internerr(taroption);
      strcpy(buffer, taroption);
      strcat(buffer, "f");
      m_dup2(p2[0],0);
      execlp(TAR,"tar",buffer,"-",(char*)0);
      ohshite("failed to exec tar");
    }
    close(p2[0]);
    waitsubproc(c3,"tar",0);
  }
  
  waitsubproc(c2,"gzip -dc",1);
  if (c1 != -1) waitsubproc(c1,"paste",0);
  if (oldformat && admininfo) {
    if (versionnum == 0.931F) {
      movecontrolfiles(OLDOLDDEBDIR);
    } else if (versionnum == 0.932F || versionnum == 0.933F) {
      movecontrolfiles(OLDDEBDIR);
    }
  }
}

static void controlextractvextract(int admin,
                                   const char *taroptions,
                                   const char *const *argv) {
  const char *debar, *directory;
  
  if (!(debar= *argv++))
    badusage("--%s needs a .deb filename argument",cipaction->olong);
  if (!(directory= *argv++)) {
    if (admin) directory= EXTRACTCONTROLDIR;
    else ohshit("--%s needs a target directory.\n"
                "Perhaps you should be using " DPKG " --install ?",cipaction->olong);
  } else if (*argv) {
    badusage("--%s takes at most two arguments (.deb and directory",cipaction->olong);
  }
  extracthalf(debar, directory, taroptions, admin);
}

void do_fsystarfile(const char *const *argv) {
  const char *debar;
  
  if (!(debar= *argv++))
    badusage("--%s needs a .deb filename argument",cipaction->olong);
  if (*argv)
    badusage("--%s takes only one argument (.deb filename)",cipaction->olong);
  extracthalf(debar,0,0,0);
}
   
void do_control(const char *const *argv) { controlextractvextract(1, "x", argv); }
void do_extract(const char *const *argv) { controlextractvextract(0, "xp", argv); }
void do_vextract(const char *const *argv) { controlextractvextract(0, "xpv", argv); }