tools: bpftool: Automate generation for "SEE ALSO" sections in man pages

The "SEE ALSO" sections of bpftool's manual pages refer to bpf(2), bpf-helpers(7), then all existing bpftool man pages (save the current one). This leads to nearly-identical lists being duplicated in all manual pages. Ideally, when a new page is created, all lists should be updated accordingly, but this has led to omissions and inconsistencies multiple times in the past. Let's take it out of the RST files and generate the "SEE ALSO" sections automatically in the Makefile when generating the man pages. The lists are not really useful in the RST anyway because all other pages are available in the same directory. v3: - Fix conflict with a previous patchset that introduced RST2MAN_OPTS variable passed to rst2man. v2: - Use "echo -n" instead of "printf" in Makefile, to avoid any risk of passing a format string directly to the command. Signed-off-by: Quentin Monnet <quentin@isovalent.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200910203935.25304-1-quentin@isovalent.com

Author: qmonnet

tools/bpf/bpftool/Documentation/Makefile

@@ -30,11 +30,21 @@ man8: $(DOC_MAN8)
 RST2MAN_DEP := $(shell command -v rst2man 2>/dev/null)
 RST2MAN_OPTS += --verbose
 
+list_pages = $(sort $(basename $(filter-out $(1),$(MAN8_RST))))
+see_also = $(subst " ",, \
+"\n" \
+"SEE ALSO\n" \
+"========\n" \
+"\t**bpf**\ (2),\n" \
+"\t**bpf-helpers**\\ (7)" \
+$(foreach page,$(call list_pages,$(1)),",\n\t**$(page)**\\ (8)") \
+"\n")
+
 $(OUTPUT)%.8: %.rst
 ifndef RST2MAN_DEP
 $(error "rst2man not found, but required to generate man pages")
 endif
-$(QUIET_GEN)rst2man $(RST2MAN_OPTS) $< > $@
+$(QUIET_GEN)( cat $< ; echo -n $(call see_also,$<) ) | rst2man $(RST2MAN_OPTS) > $@
 
 clean: helpers-clean
 $(call QUIET_CLEAN, Documentation)

tools/bpf/bpftool/Documentation/bpftool-btf.rst

@@ -217,20 +217,3 @@ All the standard ways to specify map or program are supported:
 **# bpftool btf dump prog tag b88e0a09b1d9759d**
 
 **# bpftool btf dump prog pinned /sys/fs/bpf/prog_name**
-
-SEE ALSO
-========
-**bpf**\ (2),
-**bpf-helpers**\ (7),
-**bpftool**\ (8),
-**bpftool-btf**\ (8),
-**bpftool-cgroup**\ (8),
-**bpftool-feature**\ (8),
-**bpftool-gen**\ (8),
-**bpftool-iter**\ (8),
-**bpftool-link**\ (8),
-**bpftool-map**\ (8),
-**bpftool-net**\ (8),
-**bpftool-perf**\ (8),
-**bpftool-prog**\ (8),
-**bpftool-struct_ops**\ (8)

tools/bpf/bpftool/Documentation/bpftool-cgroup.rst

@@ -143,19 +143,3 @@ EXAMPLES
 ::
 
  ID AttachType AttachFlags Name
-
-SEE ALSO
-========
-**bpf**\ (2),
-**bpf-helpers**\ (7),
-**bpftool**\ (8),
-**bpftool-btf**\ (8),
-**bpftool-feature**\ (8),
-**bpftool-gen**\ (8),
-**bpftool-iter**\ (8),
-**bpftool-link**\ (8),
-**bpftool-map**\ (8),
-**bpftool-net**\ (8),
-**bpftool-perf**\ (8),
-**bpftool-prog**\ (8),
-**bpftool-struct_ops**\ (8)

tools/bpf/bpftool/Documentation/bpftool-feature.rst

@@ -72,19 +72,3 @@ DESCRIPTION
 OPTIONS
 =======
 .. include:: common_options.rst
-
-SEE ALSO
-========
-**bpf**\ (2),
-**bpf-helpers**\ (7),
-**bpftool**\ (8),
-**bpftool-btf**\ (8),
-**bpftool-cgroup**\ (8),
-**bpftool-gen**\ (8),
-**bpftool-iter**\ (8),
-**bpftool-link**\ (8),
-**bpftool-map**\ (8),
-**bpftool-net**\ (8),
-**bpftool-perf**\ (8),
-**bpftool-prog**\ (8),
-**bpftool-struct_ops**\ (8)

tools/bpf/bpftool/Documentation/bpftool-gen.rst

@@ -279,19 +279,3 @@ and global variables.
  my_static_var: 7
 
 This is a stripped-out version of skeleton generated for above example code.
-
-SEE ALSO
-========
-**bpf**\ (2),
-**bpf-helpers**\ (7),
-**bpftool**\ (8),
-**bpftool-btf**\ (8),
-**bpftool-cgroup**\ (8),
-**bpftool-feature**\ (8),
-**bpftool-iter**\ (8),
-**bpftool-link**\ (8),
-**bpftool-map**\ (8),
-**bpftool-net**\ (8),
-**bpftool-perf**\ (8),
-**bpftool-prog**\ (8),
-**bpftool-struct_ops**\ (8)

tools/bpf/bpftool/Documentation/bpftool-iter.rst

@@ -68,19 +68,3 @@ EXAMPLES
 
  Create a file-based bpf iterator from bpf_iter_hashmap.o and map with
  id 20, and pin it to /sys/fs/bpf/my_hashmap
-
-SEE ALSO
-========
-**bpf**\ (2),
-**bpf-helpers**\ (7),
-**bpftool**\ (8),
-**bpftool-btf**\ (8),
-**bpftool-cgroup**\ (8),
-**bpftool-feature**\ (8),
-**bpftool-gen**\ (8),
-**bpftool-link**\ (8),
-**bpftool-map**\ (8),
-**bpftool-net**\ (8),
-**bpftool-perf**\ (8),
-**bpftool-prog**\ (8),
-**bpftool-struct_ops**\ (8)

tools/bpf/bpftool/Documentation/bpftool-link.rst

@@ -106,20 +106,3 @@ EXAMPLES
 ::
 
  -rw------- 1 root root 0 Apr 23 21:39 link
-
-
-SEE ALSO
-========
-**bpf**\ (2),
-**bpf-helpers**\ (7),
-**bpftool**\ (8),
-**bpftool-btf**\ (8),
-**bpftool-cgroup**\ (8),
-**bpftool-feature**\ (8),
-**bpftool-gen**\ (8),
-**bpftool-iter**\ (8),
-**bpftool-map**\ (8),
-**bpftool-net**\ (8),
-**bpftool-perf**\ (8),
-**bpftool-prog**\ (8),
-**bpftool-struct_ops**\ (8)

tools/bpf/bpftool/Documentation/bpftool-map.rst

@@ -270,19 +270,3 @@ would be lost as soon as bpftool exits).
 
  key: 00 00 00 00 value: 22 02 00 00
  Found 1 element
-
-SEE ALSO
-========
-**bpf**\ (2),
-**bpf-helpers**\ (7),
-**bpftool**\ (8),
-**bpftool-btf**\ (8),
-**bpftool-cgroup**\ (8),
-**bpftool-feature**\ (8),
-**bpftool-gen**\ (8),
-**bpftool-iter**\ (8),
-**bpftool-link**\ (8),
-**bpftool-net**\ (8),
-**bpftool-perf**\ (8),
-**bpftool-prog**\ (8),
-**bpftool-struct_ops**\ (8)

tools/bpf/bpftool/Documentation/bpftool-net.rst

@@ -172,20 +172,3 @@ EXAMPLES
 ::
 
  xdp:
-
-
-SEE ALSO
-========
-**bpf**\ (2),
-**bpf-helpers**\ (7),
-**bpftool**\ (8),
-**bpftool-btf**\ (8),
-**bpftool-cgroup**\ (8),
-**bpftool-feature**\ (8),
-**bpftool-gen**\ (8),
-**bpftool-iter**\ (8),
-**bpftool-link**\ (8),
-**bpftool-map**\ (8),
-**bpftool-perf**\ (8),
-**bpftool-prog**\ (8),
-**bpftool-struct_ops**\ (8)

tools/bpf/bpftool/Documentation/bpftool-perf.rst

@@ -63,20 +63,3 @@ EXAMPLES
  {"pid":21765,"fd":5,"prog_id":7,"fd_type":"kretprobe","func":"__x64_sys_nanosleep","offset":0}, \
  {"pid":21767,"fd":5,"prog_id":8,"fd_type":"tracepoint","tracepoint":"sys_enter_nanosleep"}, \
  {"pid":21800,"fd":5,"prog_id":9,"fd_type":"uprobe","filename":"/home/yhs/a.out","offset":1159}]
-
-
-SEE ALSO
-========
-**bpf**\ (2),
-**bpf-helpers**\ (7),
-**bpftool**\ (8),
-**bpftool-btf**\ (8),
-**bpftool-cgroup**\ (8),
-**bpftool-feature**\ (8),
-**bpftool-gen**\ (8),
-**bpftool-iter**\ (8),
-**bpftool-link**\ (8),
-**bpftool-map**\ (8),
-**bpftool-net**\ (8),
-**bpftool-prog**\ (8),
-**bpftool-struct_ops**\ (8)