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authorGary Benson <gbenson@redhat.com>2015-08-19 13:53:24 +0100
committerGary Benson <gbenson@redhat.com>2015-08-19 13:53:24 +0100
commit45face3ba147a4c5f4f7e09cf10c95986b915002 (patch)
treed0ef977ff3350dfce9501aa988e80ad47afaa6ea /gdb/gdbserver/hostio.c
parent64d94ba01a4f56ac10bb277e66bb00d82bd97f10 (diff)
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Prelimit number of bytes to read in "vFile:pread:"
While handling "vFile:pread:" packets, gdbserver would read the number of bytes requested regardless of whether this would fit into the reply packet. gdbserver would then return a packet's worth of data and discard the remainder. When accessing large binaries GDB (via BFD) routinely makes large "vFile:pread:" requests, resulting in gdbserver allocating large unnecessary buffers and reading some portions of the file many times over. This commit causes gdbserver to limit the number of bytes to be read to a sensible maximum prior to allocating buffers and reading data. gdb/gdbserver/ChangeLog: * hostio.c (handle_pread): Do not attempt to read more data than hostio_reply_with_data can fit in a packet.
Diffstat (limited to 'gdb/gdbserver/hostio.c')
-rw-r--r--gdb/gdbserver/hostio.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/gdb/gdbserver/hostio.c b/gdb/gdbserver/hostio.c
index b38a6bd..8788f07 100644
--- a/gdb/gdbserver/hostio.c
+++ b/gdb/gdbserver/hostio.c
@@ -344,6 +344,7 @@ handle_pread (char *own_buf, int *new_packet_len)
{
int fd, ret, len, offset, bytes_sent;
char *p, *data;
+ static int max_reply_size = -1;
p = own_buf + strlen ("vFile:pread:");
@@ -359,6 +360,17 @@ handle_pread (char *own_buf, int *new_packet_len)
return;
}
+ /* Do not attempt to read more than the maximum number of bytes
+ hostio_reply_with_data can fit in a packet. We may still read
+ too much because of escaping, but this is handled below. */
+ if (max_reply_size == -1)
+ {
+ sprintf (own_buf, "F%x;", PBUFSIZ);
+ max_reply_size = PBUFSIZ - strlen (own_buf);
+ }
+ if (len > max_reply_size)
+ len = max_reply_size;
+
data = xmalloc (len);
#ifdef HAVE_PREAD
ret = pread (fd, data, len, offset);