docbook: warn on unused doc entries

When you don't use !E or !I but only !F, then it's very easy to miss
including some functions, structs etc. in documentation. To help
finding which ones were missed, allow printing out the unused ones as
warnings.

For example, using this on mac80211 yields a lot of warnings like this:

Warning: didn't use docs for DOC: mac80211 workqueue
Warning: didn't use docs for ieee80211_max_queues
Warning: didn't use docs for ieee80211_bss_change
Warning: didn't use docs for ieee80211_bss_conf

when generating the documentation for it.

Signed-off-by: Johannes Berg <[e-mail]>
Signed-off-by: Randy Dunlap <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

Documentation/kernel-doc-nano-HOWTO.txt

···
 section titled <section title> from <filename>.
 Spaces are allowed in <section title>; do not quote the <section title>.
 
+!C<filename> is replaced by nothing, but makes the tools check that
+all DOC: sections and documented functions, symbols, etc. are used.
+This makes sense to use when you use !F/!P only and want to verify
+that all documentation is included.
+
 Tim.
 */ <[e-mail]>

scripts/basic/docproc.c

···
  *
  */
 
+#define _GNU_SOURCE
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <ctype.h>
 #include <unistd.h>
 #include <limits.h>
+#include <errno.h>
 #include <sys/types.h>
 #include <sys/wait.h>
 
···
 FILEONLY *internalfunctions;
 FILEONLY *externalfunctions;
 FILEONLY *symbolsonly;
+FILEONLY *findall;
 
 typedef void FILELINE(char * file, char * line);
 FILELINE * singlefunctions;
···
 #define KERNELDOCPATH "scripts/"
 #define KERNELDOC     "kernel-doc"
 #define DOCBOOK       "-docbook"
+#define LIST          "-list"
 #define FUNCTION      "-function"
 #define NOFUNCTION    "-nofunction"
 #define NODOCSECTIONS "-no-doc-sections"
 
 static char *srctree, *kernsrctree;
+
+static char **all_list = NULL;
+static int all_list_len = 0;
+
+static void consume_symbol(const char *sym)
+{
+	int i;
+
+	for (i = 0; i < all_list_len; i++) {
+		if (!all_list[i])
+			continue;
+		if (strcmp(sym, all_list[i]))
+			continue;
+		all_list[i] = NULL;
+		break;
+	}
+}
 
 static void usage (void)
 {
···
 		struct symfile * sym = &symfilelist[i];
 		for (j=0; j < sym->symbolcnt; j++) {
 			vec[idx++]     = type;
+			consume_symbol(sym->symbollist[j].name);
 			vec[idx++] = sym->symbollist[j].name;
 		}
 	}
···
                         vec[idx++] = &line[i];
                 }
         }
+	for (i = 0; i < idx; i++) {
+        	if (strcmp(vec[i], FUNCTION))
+        		continue;
+		consume_symbol(vec[i + 1]);
+	}
 	vec[idx++] = filename;
 	vec[idx] = NULL;
 	exec_kernel_doc(vec);
···
 		if (*s == '\n')
 			*s = '\0';
 
+	asprintf(&s, "DOC: %s", line);
+	consume_symbol(s);
+	free(s);
+
 	vec[0] = KERNELDOC;
 	vec[1] = DOCBOOK;
 	vec[2] = FUNCTION;
···
 	exec_kernel_doc(vec);
 }
 
+static void find_all_symbols(char *filename)
+{
+	char *vec[4]; /* kerneldoc -list file NULL */
+	pid_t pid;
+	int ret, i, count, start;
+	char real_filename[PATH_MAX + 1];
+	int pipefd[2];
+	char *data, *str;
+	size_t data_len = 0;
+
+	vec[0] = KERNELDOC;
+	vec[1] = LIST;
+	vec[2] = filename;
+	vec[3] = NULL;
+
+	if (pipe(pipefd)) {
+		perror("pipe");
+		exit(1);
+	}
+
+	switch (pid=fork()) {
+		case -1:
+			perror("fork");
+			exit(1);
+		case  0:
+			close(pipefd[0]);
+			dup2(pipefd[1], 1);
+			memset(real_filename, 0, sizeof(real_filename));
+			strncat(real_filename, kernsrctree, PATH_MAX);
+			strncat(real_filename, "/" KERNELDOCPATH KERNELDOC,
+					PATH_MAX - strlen(real_filename));
+			execvp(real_filename, vec);
+			fprintf(stderr, "exec ");
+			perror(real_filename);
+			exit(1);
+		default:
+			close(pipefd[1]);
+			data = malloc(4096);
+			do {
+				while ((ret = read(pipefd[0],
+						   data + data_len,
+						   4096)) > 0) {
+					data_len += ret;
+					data = realloc(data, data_len + 4096);
+				}
+			} while (ret == -EAGAIN);
+			if (ret != 0) {
+				perror("read");
+				exit(1);
+			}
+			waitpid(pid, &ret ,0);
+	}
+	if (WIFEXITED(ret))
+		exitstatus |= WEXITSTATUS(ret);
+	else
+		exitstatus = 0xff;
+
+	count = 0;
+	/* poor man's strtok, but with counting */
+	for (i = 0; i < data_len; i++) {
+		if (data[i] == '\n') {
+			count++;
+			data[i] = '\0';
+		}
+	}
+	start = all_list_len;
+	all_list_len += count;
+	all_list = realloc(all_list, sizeof(char *) * all_list_len);
+	str = data;
+	for (i = 0; i < data_len && start != all_list_len; i++) {
+		if (data[i] == '\0') {
+			all_list[start] = str;
+			str = data + i + 1;
+			start++;
+		}
+	}
+}
+
 /*
  * Parse file, calling action specific functions for:
  * 1) Lines containing !E
···
  * 3) Lines containing !D
  * 4) Lines containing !F
  * 5) Lines containing !P
- * 6) Default lines - lines not matching the above
+ * 6) Lines containing !C
+ * 7) Default lines - lines not matching the above
  */
 static void parse_file(FILE *infile)
 {
···
 						s++;
 					docsection(line + 2, s);
 					break;
+				case 'C':
+					while (*s && !isspace(*s)) s++;
+					*s = '\0';
+					if (findall)
+						findall(line+2);
+					break;
 				default:
 					defaultline(line);
 			}
···
 int main(int argc, char *argv[])
 {
 	FILE * infile;
+	int i;
 
 	srctree = getenv("SRCTREE");
 	if (!srctree)
···
 		symbolsonly       = find_export_symbols;
 		singlefunctions   = noaction2;
 		docsection        = noaction2;
+		findall           = find_all_symbols;
 		parse_file(infile);
 
 		/* Rewind to start from beginning of file again */
···
 		symbolsonly       = printline;
 		singlefunctions   = singfunc;
 		docsection        = docsect;
+		findall           = NULL;
 
 		parse_file(infile);
+
+		for (i = 0; i < all_list_len; i++) {
+			if (!all_list[i])
+				continue;
+			fprintf(stderr, "Warning: didn't use docs for %s\n",
+				all_list[i]);
+		}
 	}
 	else if (strcmp("depend", argv[1]) == 0)
 	{
···
 		symbolsonly       = adddep;
 		singlefunctions   = adddep2;
 		docsection        = adddep2;
+		findall           = adddep;
 		parse_file(infile);
 		printf("\n");
 	}

scripts/kernel-doc

···
 # Note: This only supports 'c'.
 
 # usage:
-# kernel-doc [ -docbook | -html | -text | -man ] [ -no-doc-sections ]
+# kernel-doc [ -docbook | -html | -text | -man | -list ] [ -no-doc-sections ]
 #           [ -function funcname [ -function funcname ...] ] c file(s)s > outputfile
 # or
 #           [ -nofunction funcname [ -function funcname ...] ] c file(s)s > outputfile
 #
 #  Set output format using one of -docbook -html -text or -man.  Default is man.
+#  The -list format is for internal use by docproc.
 #
 #  -no-doc-sections
 #	Do not output DOC: sections
···
 			$type_param, "\$1" );
 my $blankline_text = "";
 
+# list mode
+my %highlights_list = ( $type_constant, "\$1",
+			$type_func, "\$1",
+			$type_struct, "\$1",
+			$type_param, "\$1" );
+my $blankline_list = "";
 
 sub usage {
-    print "Usage: $0 [ -v ] [ -docbook | -html | -text | -man ] [ -no-doc-sections ]\n";
+    print "Usage: $0 [ -v ] [ -docbook | -html | -text | -man | -list ]\n";
+    print "         [ -no-doc-sections ]\n";
     print "         [ -function funcname [ -function funcname ...] ]\n";
     print "         [ -nofunction funcname [ -nofunction funcname ...] ]\n";
     print "         c source file(s) > outputfile\n";
···
 	$output_mode = "xml";
 	%highlights = %highlights_xml;
 	$blankline = $blankline_xml;
+    } elsif ($cmd eq "-list") {
+	$output_mode = "list";
+	%highlights = %highlights_list;
+	$blankline = $blankline_list;
     } elsif ($cmd eq "-gnome") {
 	$output_mode = "gnome";
 	%highlights = %highlights_gnome;
···
 	print " $section:\n";
 	print "    -> ";
 	output_highlight($args{'sections'}{$section});
+    }
+}
+
+## list mode output functions
+
+sub output_function_list(%) {
+    my %args = %{$_[0]};
+
+    print $args{'function'} . "\n";
+}
+
+# output enum in list
+sub output_enum_list(%) {
+    my %args = %{$_[0]};
+    print $args{'enum'} . "\n";
+}
+
+# output typedef in list
+sub output_typedef_list(%) {
+    my %args = %{$_[0]};
+    print $args{'typedef'} . "\n";
+}
+
+# output struct as list
+sub output_struct_list(%) {
+    my %args = %{$_[0]};
+
+    print $args{'struct'} . "\n";
+}
+
+sub output_blockhead_list(%) {
+    my %args = %{$_[0]};
+    my ($parameter, $section);
+
+    foreach $section (@{$args{'sectionlist'}}) {
+	print "DOC: $section\n";
     }
 }