79dcbc74cd
It is packaging responsibility to put libs in the right place. Use of lib64 resulted in huge amount of files with hardcoded lib64. This patch simplifies things... Change-Id: Iab0dea0583e480907732c5d2379eb951a00fa9e6 Signed-off-by: Damjan Marion <damarion@cisco.com>
142 lines
5.6 KiB
ReStructuredText
142 lines
5.6 KiB
ReStructuredText
.. _gdb_examples:
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.. toctree::
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GDB Examples
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===============
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In this section we have a few useful gdb commands.
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Starting GDB
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----------------------------
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Once at the gdb prompt, VPP can be started by running the following commands:
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.. code-block:: console
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(gdb) run -c /etc/vpp/startup.conf
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Starting program: /scratch/vpp-master/build-root/install-vpp_debug-native/vpp/bin/vpp -c /etc/vpp/startup.conf
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[Thread debugging using libthread_db enabled]
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Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
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vlib_plugin_early_init:361: plugin path /scratch/vpp-master/build-root/install-vpp_debug-native/vpp/lib/vpp_plugins:/scratch/vpp-master/build-root/install-vpp_debug-native/vpp/lib/vpp_plugins
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....
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Backtrace
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----------------------------
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If you encounter errors when running VPP, such as VPP terminating due to a segfault
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or abort signal, then you can run the VPP debug binary and then execute **backtrace** or **bt**.
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.. code-block:: console
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(gdb) bt
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#0 ip4_icmp_input (vm=0x7ffff7b89a40 <vlib_global_main>, node=0x7fffb6bb6900, frame=0x7fffb6725ac0) at /scratch/vpp-master/build-data/../src/vnet/ip/icmp4.c:187
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#1 0x00007ffff78da4be in dispatch_node (vm=0x7ffff7b89a40 <vlib_global_main>, node=0x7fffb6bb 6900, type=VLIB_NODE_TYPE_INTERNAL, dispatch_state=VLIB_NODE_STATE_POLLING, frame=0x7fffb6725ac0, last_time_stamp=10581236529 65565) at /scratch/vpp-master/build-data/../src/vlib/main.c:988
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#2 0x00007ffff78daa77 in dispatch_pending_node (vm=0x7ffff7b89a40 <vlib_global_main>, pending_f rame_index=6, last_time_stamp=1058123652965565) at /scratch/vpp-master/build-data/../src/vlib/main.c:1138
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....
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Get to the GDB prompt
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---------------------------------------
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When VPP is running, you can get to the command prompt by pressing **CTRL+C**.
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Breakpoints
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---------------------------------------
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When at the GDB prompt, set a breakpoint by running the commands below:
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.. code-block:: console
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(gdb) break ip4_icmp_input
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Breakpoint 4 at 0x7ffff6b9c00b: file /scratch/vpp-master/build-data/../src/vnet/ip/icmp4.c, line 142.
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List the breakpoints already set:
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.. code-block:: console
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(gdb) i b
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Num Type Disp Enb Address What
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1 breakpoint keep y 0x00007ffff6b9c00b in ip4_icmp_input at /scratch/vpp-master/build-data/../src/vnet/ip/icmp4.c:142
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breakpoint already hit 3 times
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2 breakpoint keep y 0x00007ffff6b9c00b in ip4_icmp_input at /scratch/vpp-master/build-data/../src/vnet/ip/icmp4.c:142
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3 breakpoint keep y 0x00007ffff640f646 in tw_timer_expire_timers_internal_1t_3w_1024sl_ov
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at /scratch/vpp-master/build-data/../src/vppinfra/tw_timer_template.c:775
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Delete a breakpoint:
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.. code-block:: console
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(gdb) del 2
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(gdb) i b
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Num Type Disp Enb Address What
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1 breakpoint keep y 0x00007ffff6b9c00b in ip4_icmp_input at /scratch/vpp-master/build-data/../src/vnet/ip/icmp4.c:142
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breakpoint already hit 3 times
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3 breakpoint keep y 0x00007ffff640f646 in tw_timer_expire_timers_internal_1t_3w_1024sl_ov
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at /scratch/vpp-master/build-data/../src/vppinfra/tw_timer_template.c:775
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Step/Next/List
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---------------------------------------
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Step through the code using (s)tep into, (n)ext, and list some lines before and after where you are with list.
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.. code-block:: console
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Thread 1 "vpp_main" hit Breakpoint 1, ip4_icmp_input (vm=0x7ffff7b89a40 <vlib_global_main>, node=0x7fffb6bb6900, frame=0x7fffb6709480)
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at /scratch/jdenisco/vpp-master/build-data/../src/vnet/ip/icmp4.c:142
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142 {
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(gdb) n
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143 icmp4_main_t *im = &icmp4_main;
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(
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(gdb) list
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202 vlib_put_next_frame (vm, node, next, n_left_to_next);
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203 }
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204
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205 return frame->n_vectors;
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206 }
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207
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208 /* *INDENT-OFF* */
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209 VLIB_REGISTER_NODE (ip4_icmp_input_node,static) = {
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210 .function = ip4_icmp_input,
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211 .name = "ip4-icmp-input",
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Examining Data and packets
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-----------------------------------------------
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To look at data and packets use e(x)amine or (p)rint.
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For example in this code look at the ip packet:
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.. code-block:: console
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(gdb) p/x *ip0
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$3 = {{ip_version_and_header_length = 0x45, tos = 0x0, length = 0x5400,
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fragment_id = 0x7049, flags_and_fragment_offset = 0x40, ttl = 0x40, protocol = 0x1,
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checksum = 0x2ddd, {{src_address = {data = {0xa, 0x0, 0x0, 0x2},
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data_u32 = 0x200000a, as_u8 = {0xa, 0x0, 0x0, 0x2}, as_u16 = {0xa, 0x200},
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as_u32 = 0x200000a}, dst_address = {data = {0xa, 0x0, 0x0, 0xa}, data_u32 = 0xa00000a,
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as_u8 = {0xa, 0x0, 0x0, 0xa}, as_u16 = {0xa, 0xa00}, as_u32 = 0xa00000a}},
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address_pair = {src = {data = {0xa, 0x0, 0x0, 0x2}, data_u32 = 0x200000a,
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as_u8 = {0xa, 0x0, 0x0, 0x2}, as_u16 = {0xa, 0x200}, as_u32 = 0x200000a},
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dst = {data = {0xa, 0x0, 0x0, 0xa}, data_u32 = 0xa00000a, as_u8 = {0xa, 0x0, 0x0, 0xa},
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as_u16 = {0xa, 0xa00}, as_u32 = 0xa00000a}}}}, {checksum_data_64 =
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{0x40704954000045, 0x200000a2ddd0140}, checksum_data_64_32 = {0xa00000a}},
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{checksum_data_32 = {0x54000045, 0x407049, 0x2ddd0140, 0x200000a, 0xa00000a}}}
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Then the icmp header
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.. code-block:: console
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(gdb) p/x *icmp0
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$4 = {type = 0x8, code = 0x0, checksum = 0xf148}
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Then look at the actual bytes:
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.. code-block:: console
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(gdb) x/50w ip0
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0x7fde9953510e: 0x54000045 0x00407049 0x2ddd0140 0x0200000a
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0x7fde9953511e: 0x0a00000a 0xf1480008 0x03000554 0x5b6b2e8a
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0x7fde9953512e: 0x00000000 0x000ca99a 0x00000000 0x13121110
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0x7fde9953513e: 0x17161514 0x1b1a1918 0x1f1e1d1c 0x23222120
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