unix.c

给出了 zip 压缩算法的完整实现过程。

/*
  Copyright (c) 1990-2006 Info-ZIP.  All rights reserved.

  See the accompanying file LICENSE, version 2005-Feb-10 or later
  (the contents of which are also included in zip.h) for terms of use.
  If, for some reason, both of these files are missing, the Info-ZIP license
  also may be found at:  ftp://ftp.info-zip.org/pub/infozip/license.html
*/
#include "zip.h"

#ifndef UTIL    /* the companion #endif is a bit of ways down ... */

#include <time.h>

#if defined(MINIX) || defined(__mpexl)
#  ifdef S_IWRITE
#    undef S_IWRITE
#  endif /* S_IWRITE */
#  define S_IWRITE S_IWUSR
#endif /* MINIX */

#if (!defined(S_IWRITE) && defined(S_IWUSR))
#  define S_IWRITE S_IWUSR
#endif

#if defined(HAVE_DIRENT_H) || defined(_POSIX_VERSION)
#  include <dirent.h>
#else /* !HAVE_DIRENT_H */
#  ifdef HAVE_NDIR_H
#    include <ndir.h>
#  endif /* HAVE_NDIR_H */
#  ifdef HAVE_SYS_NDIR_H
#    include <sys/ndir.h>
#  endif /* HAVE_SYS_NDIR_H */
#  ifdef HAVE_SYS_DIR_H
#    include <sys/dir.h>
#  endif /* HAVE_SYS_DIR_H */
#  ifndef dirent
#    define dirent direct
#  endif
#endif /* HAVE_DIRENT_H || _POSIX_VERSION */

#define PAD 0
#define PATH_END '/'

/* Library functions not in (most) header files */

#ifdef _POSIX_VERSION
#  include <utime.h>
#else
   int utime OF((char *, time_t *));
#endif

extern char *label;
local ulg label_time = 0;
local ulg label_mode = 0;
local time_t label_utim = 0;

/* Local functions */
local char *readd OF((DIR *));


#ifdef NO_DIR                    /* for AT&T 3B1 */
#include <sys/dir.h>
#ifndef dirent
#  define dirent direct
#endif
typedef FILE DIR;
/*
**  Apparently originally by Rich Salz.
**  Cleaned up and modified by James W. Birdsall.
*/

#define opendir(path) fopen(path, "r")

struct dirent *readdir(dirp)
DIR *dirp;
{
  static struct dirent entry;

  if (dirp == NULL)
    return NULL;
  for (;;)
    if (fread (&entry, sizeof (struct dirent), 1, dirp) == 0)
      return NULL;
    else if (entry.d_ino)
      return (&entry);
} /* end of readdir() */

#define closedir(dirp) fclose(dirp)
#endif /* NO_DIR */


local char *readd(d)
DIR *d;                 /* directory stream to read from */
/* Return a pointer to the next name in the directory stream d, or NULL if
   no more entries or an error occurs. */
{
  struct dirent *e;

  e = readdir(d);
  return e == NULL ? (char *) NULL : e->d_name;
}

int procname(n, caseflag)
char *n;                /* name to process */
int caseflag;           /* true to force case-sensitive match */
/* Process a name or sh expression to operate on (or exclude).  Return
   an error code in the ZE_ class. */
{
  char *a;              /* path and name for recursion */
  DIR *d;               /* directory stream from opendir() */
  char *e;              /* pointer to name from readd() */
  int m;                /* matched flag */
  char *p;              /* path for recursion */
  struct stat s;        /* result of stat() */
  struct zlist far *z;  /* steps through zfiles list */

  if (strcmp(n, "-") == 0)   /* if compressing stdin */
    return newname(n, 0, caseflag);
  else if (LSSTAT(n, &s))
  {
    /* Not a file or directory--search for shell expression in zip file */
    p = ex2in(n, 0, (int *)NULL);       /* shouldn't affect matching chars */
    m = 1;
    for (z = zfiles; z != NULL; z = z->nxt) {
      if (MATCH(p, z->iname, caseflag))
      {
        z->mark = pcount ? filter(z->zname, caseflag) : 1;
        if (verbose)
            fprintf(mesg, "zip diagnostic: %scluding %s\n",
               z->mark ? "in" : "ex", z->name);
        m = 0;
      }
    }
    free((zvoid *)p);
    return m ? ZE_MISS : ZE_OK;
  }

  /* Live name--use if file, recurse if directory */
#ifdef OS390
  if (S_ISREG(s.st_mode) || S_ISLNK(s.st_mode))
#else
#  ifdef S_IFLNK
  if ((s.st_mode & S_IFREG) == S_IFREG || (s.st_mode & S_IFLNK) == S_IFLNK)
#  else
  if ((s.st_mode & S_IFREG) == S_IFREG)
#  endif
#endif
  {
    /* add or remove name of file */
    if ((m = newname(n, 0, caseflag)) != ZE_OK)
      return m;
  }
#ifdef OS390
  else if (S_ISDIR(s.st_mode))
#else
  else if ((s.st_mode & S_IFDIR) == S_IFDIR)
#endif
  {
    /* Add trailing / to the directory name */
    if ((p = malloc(strlen(n)+2)) == NULL)
      return ZE_MEM;
    if (strcmp(n, ".") == 0) {
      *p = '\0';  /* avoid "./" prefix and do not create zip entry */
    } else {
      strcpy(p, n);
      a = p + strlen(p);
      if (a[-1] != '/')
        strcpy(a, "/");
      if (dirnames && (m = newname(p, 1, caseflag)) != ZE_OK) {
        free((zvoid *)p);
        return m;
      }
    }
    /* recurse into directory */
    if (recurse && (d = opendir(n)) != NULL)
    {
      while ((e = readd(d)) != NULL) {
        if (strcmp(e, ".") && strcmp(e, ".."))
        {
          if ((a = malloc(strlen(p) + strlen(e) + 1)) == NULL)
          {
            closedir(d);
            free((zvoid *)p);
            return ZE_MEM;
          }
          strcat(strcpy(a, p), e);
          if ((m = procname(a, caseflag)) != ZE_OK)   /* recurse on name */
          {
            if (m == ZE_MISS)
              zipwarn("name not matched: ", a);
            else
              ziperr(m, a);
          }
          free((zvoid *)a);
        }
      }
      closedir(d);
    }
    free((zvoid *)p);
  } /* (s.st_mode & S_IFDIR) */
#if defined(S_IFIFO) || defined(OS390)
#ifdef OS390
  else if (S_ISFIFO(s.st_mode))
#else
  else if ((s.st_mode & S_IFIFO) == S_IFIFO)
#endif
  {
    /* FIFO (Named Pipe) - handle as normal file */
    /* add or remove name of FIFO */
    if (noisy) zipwarn("FIFO (Named Pipe): ", n);
    if ((m = newname(n, 0, caseflag)) != ZE_OK)
      return m;
  }
#endif /* S_IFIFO || OS390 */
  else
    zipwarn("ignoring special file: ", n);
  return ZE_OK;
}

char *ex2in(x, isdir, pdosflag)
char *x;                /* external file name */
int isdir;              /* input: x is a directory */
int *pdosflag;          /* output: force MSDOS file attributes? */
/* Convert the external file name to a zip file name, returning the malloc'ed
   string or NULL if not enough memory. */
{
  char *n;              /* internal file name (malloc'ed) */
  char *t = NULL;       /* shortened name */
  int dosflag;

  dosflag = dosify;     /* default for non-DOS and non-OS/2 */

  /* Find starting point in name before doing malloc */
  /* Strip "//host/share/" part of a UNC name */
  if (!strncmp(x,"//",2) && (x[2] != '\0' && x[2] != '/')) {
    n = x + 2;
    while (*n != '\0' && *n != '/')
      n++;              /* strip host name */
    if (*n != '\0') {
      n++;
      while (*n != '\0' && *n != '/')
        n++;            /* strip `share' name */
    }
    if (*n != '\0')
      t = n + 1;
  } else
      t = x;
  while (*t == '/')
    t++;                /* strip leading '/' chars to get a relative path */
  while (*t == '.' && t[1] == '/')
    t += 2;             /* strip redundant leading "./" sections */

  /* Make changes, if any, to the copied name (leave original intact) */
  if (!pathput)
    t = last(t, PATH_END);

  /* Malloc space for internal name and copy it */
  if ((n = malloc(strlen(t) + 1)) == NULL)
    return NULL;
  strcpy(n, t);

  if (dosify)
    msname(n);

#ifdef EBCDIC
  strtoasc(n, n);       /* here because msname() needs native coding */
#endif

  /* Returned malloc'ed name */
  if (pdosflag)
    *pdosflag = dosflag;

  if (isdir) return n;  /* avoid warning on unused variable */
  return n;
}

char *in2ex(n)
char *n;                /* internal file name */
/* Convert the zip file name to an external file name, returning the malloc'ed
   string or NULL if not enough memory. */
{
  char *x;              /* external file name */

  if ((x = malloc(strlen(n) + 1 + PAD)) == NULL)
    return NULL;
#ifdef EBCDIC
  strtoebc(x, n);
#else
  strcpy(x, n);
#endif
  return x;
}

/*
 * XXX use ztimbuf in both POSIX and non POSIX cases ?
 */
void stamp(f, d)
char *f;                /* name of file to change */
ulg d;                  /* dos-style time to change it to */
/* Set last updated and accessed time of file f to the DOS time d. */
{
#ifdef _POSIX_VERSION
  struct utimbuf u;     /* argument for utime()  const ?? */
#else
  time_t u[2];          /* argument for utime() */
#endif

  /* Convert DOS time to time_t format in u */
#ifdef _POSIX_VERSION
  u.actime = u.modtime = dos2unixtime(d);
  utime(f, &u);
#else
  u[0] = u[1] = dos2unixtime(d);
  utime(f, u);
#endif

}

ulg filetime(f, a, n, t)
  char *f;              /* name of file to get info on */
  ulg *a;               /* return value: file attributes */
  long *n;              /* return value: file size */
  iztimes *t;           /* return value: access, modific. and creation times */
/* If file *f does not exist, return 0.  Else, return the file's last
   modified date and time as an MSDOS date and time.  The date and
   time is returned in a long with the date most significant to allow
   unsigned integer comparison of absolute times.  Also, if a is not
   a NULL pointer, store the file attributes there, with the high two
   bytes being the Unix attributes, and the low byte being a mapping
   of that to DOS attributes.  If n is not NULL, store the file size
   there.  If t is not NULL, the file's access, modification and creation
   times are stored there as UNIX time_t values.
   If f is "-", use standard input as the file. If f is a device, return
   a file size of -1 */
{
  struct stat s;        /* results of stat() */
  /* converted to pointer from using FNMAX - 11/8/04 EG */
  char *name;
  int len = strlen(f);

  if (f == label) {
    if (a != NULL)
      *a = label_mode;
    if (n != NULL)
      *n = -2L; /* convention for a label name */
    if (t != NULL)
      t->atime = t->mtime = t->ctime = label_utim;
    return label_time;
  }
  if ((name = malloc(len + 1)) == NULL) {
    ZIPERR(ZE_MEM, "filetime");
  }
  strcpy(name, f);
  if (name[len - 1] == '/')
    name[len - 1] = '\0';
  /* not all systems allow stat'ing a file with / appended */
  if (strcmp(f, "-") == 0) {
    if (fstat(fileno(stdin), &s) != 0) {
      free(name);
      error("fstat(stdin)");
    }
  }
  else if (LSSTAT(name, &s) != 0) {
    /* Accept about any file kind including directories
     * (stored with trailing / with -r option)
     */
    free(name);
    return 0;
  }
  free(name);

  if (a != NULL) {
#ifndef OS390
    *a = ((ulg)s.st_mode << 16) | !(s.st_mode & S_IWRITE);
#else
/*
**  The following defines are copied from the unizip source and represent the
**  legacy Unix mode flags.  These fixed bit masks are no longer required
**  by XOPEN standards - the S_IS### macros being the new recommended method.
**  The approach here of setting the legacy flags by testing the macros should
**  work under any _XOPEN_SOURCE environment (and will just rebuild the same bit
**  mask), but is required if the legacy bit flags differ from legacy Unix.
*/
#define UNX_IFDIR      0040000     /* Unix directory */
#define UNX_IFREG      0100000     /* Unix regular file */
#define UNX_IFSOCK     0140000     /* Unix socket (BSD, not SysV or Amiga) */
#define UNX_IFLNK      0120000     /* Unix symbolic link (not SysV, Amiga) */
#define UNX_IFBLK      0060000     /* Unix block special       (not Amiga) */
#define UNX_IFCHR      0020000     /* Unix character special   (not Amiga) */
#define UNX_IFIFO      0010000     /* Unix fifo    (BCC, not MSC or Amiga) */
    {
    mode_t legacy_modes;

    /* Initialize with permission bits--which are not implementation-optional */
    legacy_modes = s.st_mode & (S_IRWXU | S_IRWXG | S_IRWXO | S_ISUID | S_ISGID | S_ISVTX);
    if (S_ISDIR(s.st_mode))
      legacy_modes |= UNX_IFDIR;
    if (S_ISREG(s.st_mode))
      legacy_modes |= UNX_IFREG;
    if (S_ISLNK(s.st_mode))
      legacy_modes |= UNX_IFLNK;
    if (S_ISBLK(s.st_mode))
      legacy_modes |= UNX_IFBLK;
    if (S_ISCHR(s.st_mode))
      legacy_modes |= UNX_IFCHR;
    if (S_ISFIFO(s.st_mode))
      legacy_modes |= UNX_IFIFO;
    if (S_ISSOCK(s.st_mode))
      legacy_modes |= UNX_IFSOCK;
    *a = ((ulg)legacy_modes << 16) | !(s.st_mode & S_IWRITE);
    }
#endif
    if ((s.st_mode & S_IFMT) == S_IFDIR) {
      *a |= MSDOS_DIR_ATTR;
    }
  }
  if (n != NULL)
    *n = (s.st_mode & S_IFMT) == S_IFREG ? s.st_size : -1L;
  if (t != NULL) {
    t->atime = s.st_atime;