X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fgetndelim2.c;h=3c0fa3f05e9dd1d4b192ffde11f4886aeb54dbbf;hb=4142fa04c1b8254b53ec1060f8a774e73e3ffcb8;hp=db81e1b29dbf9aeeed30203c20a764a14d1d75d3;hpb=bbc37b90fa1f1723658d7d9232f96e09b9363788;p=gnulib.git diff --git a/lib/getndelim2.c b/lib/getndelim2.c index db81e1b29..3c0fa3f05 100644 --- a/lib/getndelim2.c +++ b/lib/getndelim2.c @@ -1,7 +1,7 @@ /* getndelim2 - Read a line from a stream, stopping at one of 2 delimiters, with bounded memory allocation. - Copyright (C) 1993, 1996, 1997, 1998, 2000, 2003 Free Software + Copyright (C) 1993, 1996, 1997, 1998, 2000, 2003, 2004 Free Software Foundation, Inc. This program is free software; you can redistribute it and/or modify @@ -16,90 +16,117 @@ You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, - Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ + Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ /* Originally written by Jan Brittenson, bson@gnu.ai.mit.edu. */ -#if HAVE_CONFIG_H +#ifdef HAVE_CONFIG_H # include #endif -/* Specification. */ #include "getndelim2.h" #include +#include -#include "unlocked-io.h" +#if USE_UNLOCKED_IO +# include "unlocked-io.h" +#endif + +#include +#if HAVE_INTTYPES_H +# include +#endif +#if HAVE_STDINT_H +# include +#endif +#ifndef PTRDIFF_MAX +# define PTRDIFF_MAX ((ptrdiff_t) (SIZE_MAX / 2)) +#endif +#ifndef SIZE_MAX +# define SIZE_MAX ((size_t) -1) +#endif +#ifndef SSIZE_MAX +# define SSIZE_MAX ((ssize_t) (SIZE_MAX / 2)) +#endif -/* Always add at least this many bytes when extending the buffer. */ +/* The maximum value that getndelim2 can return without suffering from + overflow problems, either internally (because of pointer + subtraction overflow) or due to the API (because of ssize_t). */ +#define GETNDELIM2_MAXIMUM (PTRDIFF_MAX < SSIZE_MAX ? PTRDIFF_MAX : SSIZE_MAX) + +/* Try to add at least this many bytes when extending the buffer. + MIN_CHUNK must be no greater than GETNDELIM2_MAXIMUM. */ #define MIN_CHUNK 64 ssize_t -getndelim2 (char **lineptr, size_t *linesize, size_t nmax, - FILE *stream, int delim1, int delim2, size_t offset) +getndelim2 (char **lineptr, size_t *linesize, size_t offset, size_t nmax, + int delim1, int delim2, FILE *stream) { - size_t nbytes_avail; /* Allocated but unused chars in *LINEPTR. */ + size_t nbytes_avail; /* Allocated but unused bytes in *LINEPTR. */ char *read_pos; /* Where we're reading into *LINEPTR. */ + ssize_t bytes_stored = -1; + char *ptr = *lineptr; + size_t size = *linesize; - if (!lineptr || !linesize || !nmax || !stream) - return -1; - - if (!*lineptr) + if (!ptr) { - size_t newlinesize = MIN_CHUNK; - - if (newlinesize > nmax) - newlinesize = nmax; - - *linesize = newlinesize; - *lineptr = malloc (*linesize); - if (!*lineptr) + size = nmax < MIN_CHUNK ? nmax : MIN_CHUNK; + ptr = malloc (size); + if (!ptr) return -1; } - if (*linesize < offset) - return -1; + if (size < offset) + goto done; - nbytes_avail = *linesize - offset; - read_pos = *lineptr + offset; + nbytes_avail = size - offset; + read_pos = ptr + offset; - if (nbytes_avail == 0 && *linesize >= nmax) - return -1; + if (nbytes_avail == 0 && nmax <= size) + goto done; for (;;) { - /* Here always *lineptr + *linesize == read_pos + nbytes_avail. */ + /* Here always ptr + size == read_pos + nbytes_avail. */ - register int c = getc (stream); + int c; - /* We always want at least one char left in the buffer, since we - always (unless we get an error while reading the first char) + /* We always want at least one byte left in the buffer, since we + always (unless we get an error while reading the first byte) NUL-terminate the line buffer. */ - if (nbytes_avail < 2 && *linesize < nmax) + if (nbytes_avail < 2 && size < nmax) { - size_t newlinesize = - (*linesize > MIN_CHUNK ? 2 * *linesize : *linesize + MIN_CHUNK); + size_t newsize = size < MIN_CHUNK ? size + MIN_CHUNK : 2 * size; + char *newptr; - if (newlinesize > nmax) - newlinesize = nmax; + if (! (size < newsize && newsize <= nmax)) + newsize = nmax; - if (newlinesize > *linesize) + if (GETNDELIM2_MAXIMUM < newsize - offset) { - *linesize = newlinesize; - nbytes_avail = *linesize + *lineptr - read_pos; - *lineptr = realloc (*lineptr, *linesize); - if (!*lineptr) - return -1; - read_pos = *linesize - nbytes_avail + *lineptr; + size_t newsizemax = offset + GETNDELIM2_MAXIMUM + 1; + if (size == newsizemax) + goto done; + newsize = newsizemax; } + + nbytes_avail = newsize - (read_pos - ptr); + newptr = realloc (ptr, newsize); + if (!newptr) + goto done; + ptr = newptr; + size = newsize; + read_pos = size - nbytes_avail + ptr; } - if (c == EOF || ferror (stream)) + c = getc (stream); + if (c == EOF) { /* Return partial line, if any. */ - if (read_pos == *lineptr) - return -1; + if (read_pos == ptr) + goto done; else break; } @@ -110,14 +137,19 @@ getndelim2 (char **lineptr, size_t *linesize, size_t nmax, nbytes_avail--; } - if (c == delim1 || (delim2 && c == delim2)) + if (c == delim1 || c == delim2) /* Return the line. */ break; } - /* Done - NUL terminate and return the number of chars read. + /* Done - NUL terminate and return the number of bytes read. At this point we know that nbytes_avail >= 1. */ *read_pos = '\0'; - return read_pos - (*lineptr + offset); + bytes_stored = read_pos - (ptr + offset); + + done: + *lineptr = ptr; + *linesize = size; + return bytes_stored; }