From d16461aeef555da47e358b0f81c75912e4ea07e2 Mon Sep 17 00:00:00 2001 From: Pedro Alves Date: Tue, 25 Feb 2014 20:45:50 -0500 Subject: Re-implement ia64-linux-nat.c::ia64_linux_xfer_partial [description of this patch and ChangeLog entry by Joel Brobecker] The recent implementation was questionable, and if it worked, it was only by chance because the requested length is large enough that only one read was sufficient. Note that the implementation before that also made that assumption, in the form of only handling TARGET_OBJECT_UNWIND_TABLE xfer requests when offset was zero. gdb/ChangeLog: * ia64-linux-nat.c (ia64_linux_xfer_partial): Reimplement handling of object == TARGET_OBJECT_UNWIND_TABLE. --- gdb/ia64-linux-nat.c | 35 +++++++++++++++++++++++------------ 1 file changed, 23 insertions(+), 12 deletions(-) (limited to 'gdb/ia64-linux-nat.c') diff --git a/gdb/ia64-linux-nat.c b/gdb/ia64-linux-nat.c index c057b55..3cfbd76 100644 --- a/gdb/ia64-linux-nat.c +++ b/gdb/ia64-linux-nat.c @@ -850,20 +850,31 @@ ia64_linux_xfer_partial (struct target_ops *ops, { if (object == TARGET_OBJECT_UNWIND_TABLE && readbuf != NULL) { - gdb_byte *tmp_buf = alloca (offset + len); - ULONGEST xfered; - - xfered = syscall (__NR_getunwind, readbuf, offset + len); - if (xfered <= 0) + static long gate_table_size; + gdb_byte *tmp_buf; + long res; + + /* Probe for the table size once. */ + if (gate_table_size == 0) + gate_table_size = syscall (__NR_getunwind, NULL, 0); + if (gate_table_size < 0) return TARGET_XFER_E_IO; - else if (xfered <= offset) + + if (offset >= gate_table_size) return TARGET_XFER_EOF; - else - { - memcpy (readbuf, tmp_buf + offset, xfered - offset); - *xfered_len = xfered - offset; - return TARGET_XFER_OK; - } + + tmp_buf = alloca (gate_table_size); + res = syscall (__NR_getunwind, tmp_buf, gate_table_size); + if (res < 0) + return TARGET_XFER_E_IO; + gdb_assert (res == gate_table_size); + + if (offset + len > gate_table_size) + len = gate_table_size - offset; + + memcpy (readbuf, tmp_buf + offset, len); + *xfered_len = len; + return TARGET_XFER_OK; } return super_xfer_partial (ops, object, annex, readbuf, writebuf, -- cgit v1.1