From b00a85c837152d486328282bb94066e835a200a7 Mon Sep 17 00:00:00 2001 From: Manuel Novoa III Date: Tue, 9 Apr 2002 17:05:32 +0000 Subject: Fix the read/write auto-transition bugs. Note that if we can't auto-transition, we fail the operation. This is different than glibc's apparent behavior for writing of clearing the read buffer and still failing the write without setting the stream's error flag. Also, change a number of "errno = xxx" assignments to use __set_errno(). Also, change setvbuf(file, NULL, _IO{LF}BF, 0) behavior to more closely match glibc's by keeping the current buffer and only changing the buffering mode. Update setlinebuf() in the process to match the man page behavior. --- libc/stdio/stdio.c | 65 ++++++++++++++++++++++++++++++------------------------ 1 file changed, 36 insertions(+), 29 deletions(-) (limited to 'libc/stdio') diff --git a/libc/stdio/stdio.c b/libc/stdio/stdio.c index 8ee1a16e2..60d4fe73b 100644 --- a/libc/stdio/stdio.c +++ b/libc/stdio/stdio.c @@ -347,7 +347,7 @@ void setbuffer(FILE * __restrict stream, register char * __restrict buf, void setlinebuf(FILE * __restrict stream) { #ifdef __STDIO_BUFFERS - setvbuf(stream, NULL, _IOLBF, (size_t) BUFSIZ); + setvbuf(stream, NULL, _IOLBF, (size_t) 0); #else /* __STDIO_BUFFERS */ /* Nothing to do. */ #endif /* __STDIO_BUFFERS */ @@ -458,7 +458,7 @@ static ssize_t fmo_write(void *cookie, register const char *buf, size_t bufsize) if (bufsize > count) { bufsize = count; if (count == 0) { /* We're at the end of the buffer... */ - errno = EFBIG; + __set_errno(EFBIG); return -1; } } @@ -632,7 +632,7 @@ static ssize_t oms_write(void *cookie, const char *buf, size_t bufsize) } else { bufsize = count; if (count == 0) { - errno = EFBIG; /* TODO: check glibc errno setting... */ + __set_errno(EFBIG); /* TODO: check glibc errno setting... */ return -1; } } @@ -1214,7 +1214,7 @@ size_t _stdio_fread(unsigned char *buffer, size_t bytes, * use this errno for read attempt while writing, as no errno is * specified by posix for this case, even though the restriction is * mentioned in fopen(). */ - errno = EBADF; + __set_errno(EBADF); return 0; } @@ -1237,9 +1237,8 @@ size_t _stdio_fread(unsigned char *buffer, size_t bytes, } #ifdef __STDIO_AUTO_RW_TRANSITION - if (stream->modeflags & __FLAG_WRITING) { - /* TODO -- return if error? Test glibc behavior with a custom r/w. */ - fflush(stream); + if ((stream->modeflags & __FLAG_WRITING) && (fflush(stream) == EOF)) { + return 0; /* Fail if we need to fflush but can't. */ } #endif /* __STDIO_AUTO_RW_TRANSITION */ @@ -1316,7 +1315,7 @@ size_t _stdio_fread(unsigned char *buffer, size_t bytes, * use this errno for read attempt while writing, as no errno is * specified by posix for this case, even though the restriction is * mentioned in fopen(). */ - errno = EBADF; + __set_errno(EBADF); return 0; } @@ -1431,35 +1430,39 @@ size_t _stdio_fwrite(const unsigned char *buffer, size_t bytes, * use this errno for write attempt while reading, as no errno is * specified by posix for this case, even though the restriction is * mentioned in fopen(). */ - errno = EBADF; + __set_errno(EBADF); return 0; } #ifdef __STDIO_AUTO_RW_TRANSITION - /* If we were reading, deal with ungots and buffered chars. */ - if ((stream->modeflags & (__FLAG_EOF|__FLAG_WRITING|__FLAG_WRITEONLY)) - == 0) { - /* If appending, we might as well seek to end to save a seek. */ - fseek(stream, 0L, - ((stream->modeflags & __FLAG_APPEND) ? SEEK_END : SEEK_CUR)); - /* TODO: set EOF in fseek when appropriate? */ + /* If reading, deal with ungots and read-buffered chars. */ + if (stream->modeflags & __FLAG_READING) { + if (((stream->bufrpos < stream->bufwpos) + || (stream->modeflags & __MASK_UNGOT)) + /* If appending, we might as well seek to end to save a seek. */ + /* TODO: set EOF in fseek when appropriate? */ + && fseek(stream, 0L, + ((stream->modeflags & __FLAG_APPEND) + ? SEEK_END : SEEK_CUR)) + ) { + /* Note: This differs from glibc's apparent behavior of + not setting the error flag and discarding the buffered + read data. */ + stream->modeflags |= __FLAG_ERROR; /* fseek may not set this. */ + return 0; /* Fail if we need to fseek but can't. */ + } + /* Always reset even if fseek called (saves a test). */ +#ifdef __STDIO_GETC_MACRO + stream->bufgetc = +#endif /* __STDIO_GETC_MACRO */ + stream->bufrpos = stream->bufwpos = stream->bufstart; } #endif - /* We need to disable putc and getc macros in case of error */ -#if defined(__STDIO_AUTO_RW_TRANSITION) \ - || defined(__STDIO_PUTC_MACRO) || defined(__STDIO_GETC_MACRO) -#ifdef __STDIO_AUTO_RW_TRANSITION - stream->bufrpos = /* TODO -- necessary? */ -#endif /* __STDIO_AUTO_RW_TRANSITION */ #ifdef __STDIO_PUTC_MACRO - stream->bufputc = + /* We need to disable putc macro in case of error */ + stream->bufputc = stream->bufstart; #endif /* __STDIO_GETC_MACRO */ -#ifdef __STDIO_GETC_MACRO - stream->bufgetc = -#endif /* __STDIO_GETC_MACRO */ - stream->bufstart; -#endif /* not using ansi restrictions ; or using putc and/or getc macro */ /* Clear both reading and writing flags. We need to clear the writing * flag in case we're fflush()ing or in case of an error. */ @@ -1568,7 +1571,7 @@ size_t _stdio_fwrite(const unsigned char *buffer, size_t bytes, * use this errno for write attempt while reading, as no errno is * specified by posix for this case, even though the restriction is * mentioned in fopen(). */ - errno = EBADF; + __set_errno(EBADF); return 0; } @@ -2408,6 +2411,10 @@ int setvbuf(register FILE * __restrict stream, register char * __restrict buf, if (mode == _IONBF) { size = 0; buf = NULL; + } else if (!buf && !size) { + /* If buf==NULL && size==0 && either _IOFBF or _IOLBF, keep + * current buffer and only set buffering mode. */ + size = stream->bufend - stream->bufstart; } stream->modeflags &= ~(__MASK_BUFMODE); /* Clear current mode */ -- cgit v1.2.3