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authorhpa <hpa>2004-11-10 22:31:50 +0000
committerhpa <hpa>2004-11-10 22:31:50 +0000
commit17f967640cef484f83d755c9dd016a946711236f (patch)
tree00bf0c0f2926cd6a9761eb372b55d090305aca44 /com32/lib/sys/read.c
parentc67a2ac96611fa6aeb9ff3602c5e0c8265f1cc9d (diff)
downloadsyslinux-17f967640cef484f83d755c9dd016a946711236f.tar.gz
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Very first cut at a klibc-derived C library for com32
Diffstat (limited to 'com32/lib/sys/read.c')
-rw-r--r--com32/lib/sys/read.c92
1 files changed, 92 insertions, 0 deletions
diff --git a/com32/lib/sys/read.c b/com32/lib/sys/read.c
new file mode 100644
index 00000000..1c16ce47
--- /dev/null
+++ b/com32/lib/sys/read.c
@@ -0,0 +1,92 @@
+#ident "$Id$"
+/* ----------------------------------------------------------------------- *
+ *
+ * Copyright 2004 H. Peter Anvin - All Rights Reserved
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom
+ * the Software is furnished to do so, subject to the following
+ * conditions:
+ *
+ * The above copyright notice and this permission notice shall
+ * be included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * read.c
+ *
+ * Reading from a file
+ */
+
+#include <errno.h>
+#include <string.h>
+#include <com32.h>
+#include <minmax.h>
+#include "file.h"
+
+ssize_t read(int fd, void *buf, size_t count)
+{
+ com32sys_t ireg, oreg;
+ struct file_info *fp = &__file_info[fd];
+ char *bufp = buf;
+ size_t n = 0;
+ size_t ncopy;
+
+ if ( fd >= NFILES || fp->blocklg2 == 0 ) {
+ errno = EBADF;
+ return -1;
+ }
+
+ memset(&ireg, 0, sizeof ireg);
+ ireg.eax.w[0] = 0x0007; /* Read file */
+ ireg.esi.w[0] = OFFS(__com32.cs_bounce);
+ ireg.es = SEG(__com32.cs_bounce);
+
+ while ( count ) {
+ if ( fp->nbytes == 0 ) {
+ if ( fp->offset >= fp->length || !fp->filedes )
+ return n; /* As good as it gets... */
+
+ ireg.esi.w[0] = fp->filedes;
+ ireg.ecx.w[0] = MAXBLOCK >> fp->blocklg2;
+
+ __intcall(0x22, &ireg, &oreg);
+
+ if ( oreg.eflags.l & EFLAGS_CF ) {
+ errno = EIO;
+ return -1;
+ }
+
+ fp->filedes = ireg.esi.w[0];
+ fp->nbytes = min(fp->length-fp->offset, (unsigned)MAXBLOCK);
+ fp->datap = fp->buf;
+ memcpy(fp->buf, __com32.cs_bounce, fp->nbytes);
+ }
+
+ ncopy = min(count, fp->nbytes);
+ memcpy(bufp, fp->datap, ncopy);
+
+ n += ncopy;
+ bufp += ncopy;
+ count -= ncopy;
+ fp->datap += ncopy;
+ fp->offset += ncopy;
+ fp->nbytes -= ncopy;
+ }
+
+ return n;
+}