/* gzlib.c -- zlib functions common to reading and writing gzip files * Copyright (C) 2004-2019 Mark Adler * For conditions of distribution and use, see copyright notice in zlib.h */ #include "gzguts.h" #if defined(_WIN32) && !defined(__BORLANDC__) # define LSEEK _lseeki64 #else #if defined(_LARGEFILE64_SOURCE) && _LFS64_LARGEFILE-0 # define LSEEK lseek64 #else # define LSEEK lseek #endif #endif #if defined UNDER_CE /* Map the Windows error number in ERROR to a locale-dependent error message string and return a pointer to it. Typically, the values for ERROR come from GetLastError. The string pointed to shall not be modified by the application, but may be overwritten by a subsequent call to gz_strwinerror The gz_strwinerror function does not change the current setting of GetLastError. */ char ZLIB_INTERNAL *gz_strwinerror(DWORD error) { static char buf[1024]; wchar_t *msgbuf; DWORD lasterr = GetLastError(); DWORD chars = FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_ALLOCATE_BUFFER, NULL, error, 0, /* Default language */ (LPVOID)&msgbuf, 0, NULL); if (chars != 0) { /* If there is an \r\n appended, zap it. */ if (chars >= 2 && msgbuf[chars - 2] == '\r' && msgbuf[chars - 1] == '\n') { chars -= 2; msgbuf[chars] = 0; } if (chars > sizeof (buf) - 1) { chars = sizeof (buf) - 1; msgbuf[chars] = 0; } wcstombs(buf, msgbuf, chars + 1); LocalFree(msgbuf); } else { sprintf(buf, "unknown win32 error (%ld)", error); } SetLastError(lasterr); return buf; } #endif /* UNDER_CE */ /* Reset gzip file state */ local void gz_reset(gz_statep state) { state->x.have = 0; /* no output data available */ if (state->mode == GZ_READ) { /* for reading ... */ state->eof = 0; /* not at end of file */ state->past = 0; /* have not read past end yet */ state->how = LOOK; /* look for gzip header */ } else /* for writing ... */ state->reset = 0; /* no deflateReset pending */ state->seek = 0; /* no seek request pending */ gz_error(state, Z_OK, NULL); /* clear error */ state->x.pos = 0; /* no uncompressed data yet */ state->strm.avail_in = 0; /* no input data yet */ } /* Open a gzip file either by name or file descriptor. */ local gzFile gz_open(const void *path, int fd, const char *mode) { gz_statep state; z_size_t len; int oflag; #ifdef O_CLOEXEC int cloexec = 0; #endif #ifdef O_EXCL int exclusive = 0; #endif /* check input */ if (path == NULL) return NULL; /* allocate gzFile structure to return */ state = (gz_statep)malloc(sizeof(gz_state)); if (state == NULL) return NULL; state->size = 0; /* no buffers allocated yet */ state->want = GZBUFSIZE; /* requested buffer size */ state->msg = NULL; /* no error message yet */ /* interpret mode */ state->mode = GZ_NONE; state->level = Z_DEFAULT_COMPRESSION; state->strategy = Z_DEFAULT_STRATEGY; state->direct = 0; while (*mode) { if (*mode >= '0' && *mode <= '9') state->level = *mode - '0'; else switch (*mode) { case 'r': state->mode = GZ_READ; break; #ifndef NO_GZCOMPRESS case 'w': state->mode = GZ_WRITE; break; case 'a': state->mode = GZ_APPEND; break; #endif case '+': /* can't read and write at the same time */ free(state); return NULL; case 'b': /* ignore -- will request binary anyway */ break; #ifdef O_CLOEXEC case 'e': cloexec = 1; break; #endif #ifdef O_EXCL case 'x': exclusive = 1; break; #endif case 'f': state->strategy = Z_FILTERED; break; case 'h': state->strategy = Z_HUFFMAN_ONLY; break; case 'R': state->strategy = Z_RLE; break; case 'F': state->strategy = Z_FIXED; break; case 'T': state->direct = 1; break; default: /* could consider as an error, but just ignore */ ; } mode++; } /* must provide an "r", "w", or "a" */ if (state->mode == GZ_NONE) { free(state); return NULL; } /* can't force transparent read */ if (state->mode == GZ_READ) { if (state->direct) { free(state); return NULL; } state->direct = 1; /* for empty file */ } /* save the path name for error messages */ #ifdef WIDECHAR if (fd == -2) { len = wcstombs(NULL, path, 0); if (len == (z_size_t)-1) len = 0; } else #endif len = strlen((const char *)path); state->path = (char *)malloc(len + 1); if (state->path == NULL) { free(state); return NULL; } #ifdef WIDECHAR if (fd == -2) if (len) wcstombs(state->path, path, len + 1); else *(state->path) = 0; else #endif #if !defined(NO_snprintf) && !defined(NO_vsnprintf) (void)snprintf(state->path, len + 1, "%s", (const char *)path); #else strcpy(state->path, path); #endif /* compute the flags for open() */ oflag = #ifdef O_LARGEFILE O_LARGEFILE | #endif #ifdef O_BINARY O_BINARY | #endif #ifdef O_CLOEXEC (cloexec ? O_CLOEXEC : 0) | #endif (state->mode == GZ_READ ? O_RDONLY : (O_WRONLY | O_CREAT | #ifdef O_EXCL (exclusive ? O_EXCL : 0) | #endif (state->mode == GZ_WRITE ? O_TRUNC : O_APPEND))); /* open the file with the appropriate flags (or just use fd) */ state->fd = fd > -1 ? fd : ( #ifdef WIDECHAR fd == -2 ? _wopen(path, oflag, 0666) : #endif open((const char *)path, oflag, 0666)); if (state->fd == -1) { free(state->path); free(state); return NULL; } if (state->mode == GZ_APPEND) { LSEEK(state->fd, 0, SEEK_END); /* so gzoffset() is correct */ state->mode = GZ_WRITE; /* simplify later checks */ } /* save the current position for rewinding (only if reading) */ if (state->mode == GZ_READ) { state->start = LSEEK(state->fd, 0, SEEK_CUR); if (state->start == -1) state->start = 0; } /* initialize stream */ gz_reset(state); /* return stream */ return (gzFile)state; } /* -- see zlib.h -- */ gzFile ZEXPORT gzopen(const char *path, const char *mode) { return gz_open(path, -1, mode); } /* -- see zlib.h -- */ gzFile ZEXPORT gzopen64(const char *path, const char *mode) { return gz_open(path, -1, mode); } /* -- see zlib.h -- */ gzFile ZEXPORT gzdopen(int fd, const char *mode) { char *path; /* identifier for error messages */ gzFile gz; if (fd == -1 || (path = (char *)malloc(7 + 3 * sizeof(int))) == NULL) return NULL; #if !defined(NO_snprintf) && !defined(NO_vsnprintf) (void)snprintf(path, 7 + 3 * sizeof(int), "<fd:%d>", fd); #else sprintf(path, "<fd:%d>", fd); /* for debugging */ #endif gz = gz_open(path, fd, mode); free(path); return gz; } /* -- see zlib.h -- */ #ifdef WIDECHAR gzFile ZEXPORT gzopen_w(const wchar_t *path, const char *mode) { return gz_open(path, -2, mode); } #endif /* -- see zlib.h -- */ int ZEXPORT gzbuffer(gzFile file, unsigned size) { gz_statep state; /* get internal structure and check integrity */ if (file == NULL) return -1; state = (gz_statep)file; if (state->mode != GZ_READ && state->mode != GZ_WRITE) return -1; /* make sure we haven't already allocated memory */ if (state->size != 0) return -1; /* check and set requested size */ if ((size << 1) < size) return -1; /* need to be able to double it */ if (size < 8) size = 8; /* needed to behave well with flushing */ state->want = size; return 0; } /* -- see zlib.h -- */ int ZEXPORT gzrewind(gzFile file) { gz_statep state; /* get internal structure */ if (file == NULL) return -1; state = (gz_statep)file; /* check that we're reading and that there's no error */ if (state->mode != GZ_READ || (state->err != Z_OK && state->err != Z_BUF_ERROR)) return -1; /* back up and start over */ if (LSEEK(state->fd, state->start, SEEK_SET) == -1) return -1; gz_reset(state); return 0; } /* -- see zlib.h -- */ z_off64_t ZEXPORT gzseek64(gzFile file, z_off64_t offset, int whence) { unsigned n; z_off64_t ret; gz_statep state; /* get internal structure and check integrity */ if (file == NULL) return -1; state = (gz_statep)file; if (state->mode != GZ_READ && state->mode != GZ_WRITE) return -1; /* check that there's no error */ if (state->err != Z_OK && state->err != Z_BUF_ERROR) return -1; /* can only seek from start or relative to current position */ if (whence != SEEK_SET && whence != SEEK_CUR) return -1; /* normalize offset to a SEEK_CUR specification */ if (whence == SEEK_SET) offset -= state->x.pos; else if (state->seek) offset += state->skip; state->seek = 0; /* if within raw area while reading, just go there */ if (state->mode == GZ_READ && state->how == COPY && state->x.pos + offset >= 0) { ret = LSEEK(state->fd, offset - (z_off64_t)state->x.have, SEEK_CUR); if (ret == -1) return -1; state->x.have = 0; state->eof = 0; state->past = 0; state->seek = 0; gz_error(state, Z_OK, NULL); state->strm.avail_in = 0; state->x.pos += offset; return state->x.pos; } /* calculate skip amount, rewinding if needed for back seek when reading */ if (offset < 0) { if (state->mode != GZ_READ) /* writing -- can't go backwards */ return -1; offset += state->x.pos; if (offset < 0) /* before start of file! */ return -1; if (gzrewind(file) == -1) /* rewind, then skip to offset */ return -1; } /* if reading, skip what's in output buffer (one less gzgetc() check) */ if (state->mode == GZ_READ) { n = GT_OFF(state->x.have) || (z_off64_t)state->x.have > offset ? (unsigned)offset : state->x.have; state->x.have -= n; state->x.next += n; state->x.pos += n; offset -= n; } /* request skip (if not zero) */ if (offset) { state->seek = 1; state->skip = offset; } return state->x.pos + offset; } /* -- see zlib.h -- */ z_off_t ZEXPORT gzseek(gzFile file, z_off_t offset, int whence) { z_off64_t ret; ret = gzseek64(file, (z_off64_t)offset, whence); return ret == (z_off_t)ret ? (z_off_t)ret : -1; } /* -- see zlib.h -- */ z_off64_t ZEXPORT gztell64(gzFile file) { gz_statep state; /* get internal structure and check integrity */ if (file == NULL) return -1; state = (gz_statep)file; if (state->mode != GZ_READ && state->mode != GZ_WRITE) return -1; /* return position */ return state->x.pos + (state->seek ? state->skip : 0); } /* -- see zlib.h -- */ z_off_t ZEXPORT gztell(gzFile file) { z_off64_t ret; ret = gztell64(file); return ret == (z_off_t)ret ? (z_off_t)ret : -1; } /* -- see zlib.h -- */ z_off64_t ZEXPORT gzoffset64(gzFile file) { z_off64_t offset; gz_statep state; /* get internal structure and check integrity */ if (file == NULL) return -1; state = (gz_statep)file; if (state->mode != GZ_READ && state->mode != GZ_WRITE) return -1; /* compute and return effective offset in file */ offset = LSEEK(state->fd, 0, SEEK_CUR); if (offset == -1) return -1; if (state->mode == GZ_READ) /* reading */ offset -= state->strm.avail_in; /* don't count buffered input */ return offset; } /* -- see zlib.h -- */ z_off_t ZEXPORT gzoffset(gzFile file) { z_off64_t ret; ret = gzoffset64(file); return ret == (z_off_t)ret ? (z_off_t)ret : -1; } /* -- see zlib.h -- */ int ZEXPORT gzeof(gzFile file) { gz_statep state; /* get internal structure and check integrity */ if (file == NULL) return 0; state = (gz_statep)file; if (state->mode != GZ_READ && state->mode != GZ_WRITE) return 0; /* return end-of-file state */ return state->mode == GZ_READ ? state->past : 0; } /* -- see zlib.h -- */ const char * ZEXPORT gzerror(gzFile file, int *errnum) { gz_statep state; /* get internal structure and check integrity */ if (file == NULL) return NULL; state = (gz_statep)file; if (state->mode != GZ_READ && state->mode != GZ_WRITE) return NULL; /* return error information */ if (errnum != NULL) *errnum = state->err; return state->err == Z_MEM_ERROR ? "out of memory" : (state->msg == NULL ? "" : state->msg); } /* -- see zlib.h -- */ void ZEXPORT gzclearerr(gzFile file) { gz_statep state; /* get internal structure and check integrity */ if (file == NULL) return; state = (gz_statep)file; if (state->mode != GZ_READ && state->mode != GZ_WRITE) return; /* clear error and end-of-file */ if (state->mode == GZ_READ) { state->eof = 0; state->past = 0; } gz_error(state, Z_OK, NULL); } /* Create an error message in allocated memory and set state->err and state->msg accordingly. Free any previous error message already there. Do not try to free or allocate space if the error is Z_MEM_ERROR (out of memory). Simply save the error message as a static string. If there is an allocation failure constructing the error message, then convert the error to out of memory. */ void ZLIB_INTERNAL gz_error(gz_statep state, int err, const char *msg) { /* free previously allocated message and clear */ if (state->msg != NULL) { if (state->err != Z_MEM_ERROR) free(state->msg); state->msg = NULL; } /* if fatal, set state->x.have to 0 so that the gzgetc() macro fails */ if (err != Z_OK && err != Z_BUF_ERROR) state->x.have = 0; /* set error code, and if no message, then done */ state->err = err; if (msg == NULL) return; /* for an out of memory error, return literal string when requested */ if (err == Z_MEM_ERROR) return; /* construct error message with path */ if ((state->msg = (char *)malloc(strlen(state->path) + strlen(msg) + 3)) == NULL) { state->err = Z_MEM_ERROR; return; } #if !defined(NO_snprintf) && !defined(NO_vsnprintf) (void)snprintf(state->msg, strlen(state->path) + strlen(msg) + 3, "%s%s%s", state->path, ": ", msg); #else strcpy(state->msg, state->path); strcat(state->msg, ": "); strcat(state->msg, msg); #endif } #ifndef INT_MAX /* portably return maximum value for an int (when limits.h presumed not available) -- we need to do this to cover cases where 2's complement not used, since C standard permits 1's complement and sign-bit representations, otherwise we could just use ((unsigned)-1) >> 1 */ unsigned ZLIB_INTERNAL gz_intmax(void) { unsigned p, q; p = 1; do { q = p; p <<= 1; p++; } while (p > q); return q >> 1; } #endif