kerneldoc: Implant DocBook from Linux kernel

Pull slightly modified version of Documentation/DocBook, the related perl
script scripts/kernel-doc and the scripts/docproc.c from Linux kernel and
implant it into U-Boot. This will allow smooth generation of kerneldoc
style documentation.

It was necessary to modify the DocBook/Makefile to work with U-Boot build
system. The changes were only minor though and involved replacing the kbuild
specific parts.

It was also necessary to replace use of variables like KERNEL_VERSION with
U_BOOT_VERSION, strings like Linux kernel with U-Boot Bootloader etc. so
the generated result actually matches.

Finally, it was necessary to adjust docproc.c, since the documentation in
U-Boot is located in doc/DocBook instead of Documentation/DocBook as is in
case of the Linux kernel.

Some parts of the DocBook Makefile are unused, but to allow easier sync with
Linux kernel, these parts are still left in. The targets enabled now are
"htmldocs" "pdfdocs" "psdocs" "xmldocs" and "cleandocs" to remove the results
of documentation build.

Linux scripts/docproc.c:
commit f0f3ca8d967462dafb815412b14ca3339b9817a6
Date:   Wed Jun 15 11:53:13 2011 +0200

Linux scripts/kernel-doc:
commit 1b40c1944db445c1de1c47ffd8cd426167f488e8
Date:   Sun Aug 12 10:46:15 2012 +0200

Linux Documentation/DocBook:
commit bb8187d35f820671d6dd76700d77a6b55f95e2c5
Date:   Thu May 17 19:06:13 2012 -0400

Signed-off-by: Marek Vasut <marex@denx.de>

1 files changed, 576 insertions, 0 deletions

diff --git a/tools/kernel-doc/docproc.c b/tools/kernel-doc/docproc.c
new file mode 100644
index 0000000000..d4fc42e4cc
--- /dev/null
+++ b/tools/kernel-doc/docproc.c
@@ -0,0 +1,576 @@
+/*
+ *	docproc is a simple preprocessor for the template files
+ *      used as placeholders for the kernel internal documentation.
+ *	docproc is used for documentation-frontend and
+ *      dependency-generator.
+ *	The two usages have in common that they require
+ *	some knowledge of the .tmpl syntax, therefore they
+ *	are kept together.
+ *
+ *	documentation-frontend
+ *		Scans the template file and call kernel-doc for
+ *		all occurrences of ![EIF]file
+ *		Beforehand each referenced file is scanned for
+ *		any symbols that are exported via these macros:
+ *			EXPORT_SYMBOL(), EXPORT_SYMBOL_GPL(), &
+ *			EXPORT_SYMBOL_GPL_FUTURE()
+ *		This is used to create proper -function and
+ *		-nofunction arguments in calls to kernel-doc.
+ *		Usage: docproc doc file.tmpl
+ *
+ *	dependency-generator:
+ *		Scans the template file and list all files
+ *		referenced in a format recognized by make.
+ *		Usage:	docproc depend file.tmpl
+ *		Writes dependency information to stdout
+ *		in the following format:
+ *		file.tmpl src.c	src2.c
+ *		The filenames are obtained from the following constructs:
+ *		!Efilename
+ *		!Ifilename
+ *		!Dfilename
+ *		!Ffilename
+ *		!Pfilename
+ *
+ */
+
+#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>
+
+/* exitstatus is used to keep track of any failing calls to kernel-doc,
+ * but execution continues. */
+int exitstatus = 0;
+
+typedef void DFL(char *);
+DFL *defaultline;
+
+typedef void FILEONLY(char * file);
+FILEONLY *internalfunctions;
+FILEONLY *externalfunctions;
+FILEONLY *symbolsonly;
+FILEONLY *findall;
+
+typedef void FILELINE(char * file, char * line);
+FILELINE * singlefunctions;
+FILELINE * entity_system;
+FILELINE * docsection;
+
+#define MAXLINESZ     2048
+#define MAXFILES      250
+#define KERNELDOCPATH "tools/kernel-doc/"
+#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)
+{
+	fprintf(stderr, "Usage: docproc {doc|depend} file\n");
+	fprintf(stderr, "Input is read from file.tmpl. Output is sent to stdout\n");
+	fprintf(stderr, "doc: frontend when generating kernel documentation\n");
+	fprintf(stderr, "depend: generate list of files referenced within file\n");
+	fprintf(stderr, "Environment variable SRCTREE: absolute path to sources.\n");
+	fprintf(stderr, "                     KBUILD_SRC: absolute path to kernel source tree.\n");
+}
+
+/*
+ * Execute kernel-doc with parameters given in svec
+ */
+static void exec_kernel_doc(char **svec)
+{
+	pid_t pid;
+	int ret;
+	char real_filename[PATH_MAX + 1];
+	/* Make sure output generated so far are flushed */
+	fflush(stdout);
+	switch (pid=fork()) {
+		case -1:
+			perror("fork");
+			exit(1);
+		case  0:
+			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, svec);
+			fprintf(stderr, "exec ");
+			perror(real_filename);
+			exit(1);
+		default:
+			waitpid(pid, &ret ,0);
+	}
+	if (WIFEXITED(ret))
+		exitstatus |= WEXITSTATUS(ret);
+	else
+		exitstatus = 0xff;
+}
+
+/* Types used to create list of all exported symbols in a number of files */
+struct symbols
+{
+	char *name;
+};
+
+struct symfile
+{
+	char *filename;
+	struct symbols *symbollist;
+	int symbolcnt;
+};
+
+struct symfile symfilelist[MAXFILES];
+int symfilecnt = 0;
+
+static void add_new_symbol(struct symfile *sym, char * symname)
+{
+	sym->symbollist =
+          realloc(sym->symbollist, (sym->symbolcnt + 1) * sizeof(char *));
+	sym->symbollist[sym->symbolcnt++].name = strdup(symname);
+}
+
+/* Add a filename to the list */
+static struct symfile * add_new_file(char * filename)
+{
+	symfilelist[symfilecnt++].filename = strdup(filename);
+	return &symfilelist[symfilecnt - 1];
+}
+
+/* Check if file already are present in the list */
+static struct symfile * filename_exist(char * filename)
+{
+	int i;
+	for (i=0; i < symfilecnt; i++)
+		if (strcmp(symfilelist[i].filename, filename) == 0)
+			return &symfilelist[i];
+	return NULL;
+}
+
+/*
+ * List all files referenced within the template file.
+ * Files are separated by tabs.
+ */
+static void adddep(char * file)		   { printf("\t%s", file); }
+static void adddep2(char * file, char * line)     { line = line; adddep(file); }
+static void noaction(char * line)		   { line = line; }
+static void noaction2(char * file, char * line)   { file = file; line = line; }
+
+/* Echo the line without further action */
+static void printline(char * line)               { printf("%s", line); }
+
+/*
+ * Find all symbols in filename that are exported with EXPORT_SYMBOL &
+ * EXPORT_SYMBOL_GPL (& EXPORT_SYMBOL_GPL_FUTURE implicitly).
+ * All symbols located are stored in symfilelist.
+ */
+static void find_export_symbols(char * filename)
+{
+	FILE * fp;
+	struct symfile *sym;
+	char line[MAXLINESZ];
+	if (filename_exist(filename) == NULL) {
+		char real_filename[PATH_MAX + 1];
+		memset(real_filename, 0, sizeof(real_filename));
+		strncat(real_filename, srctree, PATH_MAX);
+		strncat(real_filename, "/", PATH_MAX - strlen(real_filename));
+		strncat(real_filename, filename,
+				PATH_MAX - strlen(real_filename));
+		sym = add_new_file(filename);
+		fp = fopen(real_filename, "r");
+		if (fp == NULL)	{
+			fprintf(stderr, "docproc: ");
+			perror(real_filename);
+			exit(1);
+		}
+		while (fgets(line, MAXLINESZ, fp)) {
+			char *p;
+			char *e;
+			if (((p = strstr(line, "EXPORT_SYMBOL_GPL")) != NULL) ||
+                            ((p = strstr(line, "EXPORT_SYMBOL")) != NULL)) {
+				/* Skip EXPORT_SYMBOL{_GPL} */
+				while (isalnum(*p) || *p == '_')
+					p++;
+				/* Remove parentheses & additional whitespace */
+				while (isspace(*p))
+					p++;
+				if (*p != '(')
+					continue; /* Syntax error? */
+				else
+					p++;
+				while (isspace(*p))
+					p++;
+				e = p;
+				while (isalnum(*e) || *e == '_')
+					e++;
+				*e = '\0';
+				add_new_symbol(sym, p);
+			}
+		}
+		fclose(fp);
+	}
+}
+
+/*
+ * Document all external or internal functions in a file.
+ * Call kernel-doc with following parameters:
+ * kernel-doc -docbook -nofunction function_name1 filename
+ * Function names are obtained from all the src files
+ * by find_export_symbols.
+ * intfunc uses -nofunction
+ * extfunc uses -function
+ */
+static void docfunctions(char * filename, char * type)
+{
+	int i,j;
+	int symcnt = 0;
+	int idx = 0;
+	char **vec;
+
+	for (i=0; i <= symfilecnt; i++)
+		symcnt += symfilelist[i].symbolcnt;
+	vec = malloc((2 + 2 * symcnt + 3) * sizeof(char *));
+	if (vec == NULL) {
+		perror("docproc: ");
+		exit(1);
+	}
+	vec[idx++] = KERNELDOC;
+	vec[idx++] = DOCBOOK;
+	vec[idx++] = NODOCSECTIONS;
+	for (i=0; i < symfilecnt; i++) {
+		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++]     = filename;
+	vec[idx] = NULL;
+	printf("<!-- %s -->\n", filename);
+	exec_kernel_doc(vec);
+	fflush(stdout);
+	free(vec);
+}
+static void intfunc(char * filename) {	docfunctions(filename, NOFUNCTION); }
+static void extfunc(char * filename) { docfunctions(filename, FUNCTION);   }
+
+/*
+ * Document specific function(s) in a file.
+ * Call kernel-doc with the following parameters:
+ * kernel-doc -docbook -function function1 [-function function2]
+ */
+static void singfunc(char * filename, char * line)
+{
+	char *vec[200]; /* Enough for specific functions */
+        int i, idx = 0;
+        int startofsym = 1;
+	vec[idx++] = KERNELDOC;
+	vec[idx++] = DOCBOOK;
+
+        /* Split line up in individual parameters preceded by FUNCTION */
+        for (i=0; line[i]; i++) {
+                if (isspace(line[i])) {
+                        line[i] = '\0';
+                        startofsym = 1;
+                        continue;
+                }
+                if (startofsym) {
+                        startofsym = 0;
+                        vec[idx++] = FUNCTION;
+                        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);
+}
+
+/*
+ * Insert specific documentation section from a file.
+ * Call kernel-doc with the following parameters:
+ * kernel-doc -docbook -function "doc section" filename
+ */
+static void docsect(char *filename, char *line)
+{
+	char *vec[6]; /* kerneldoc -docbook -function "section" file NULL */
+	char *s;
+
+	for (s = line; *s; s++)
+		if (*s == '\n')
+			*s = '\0';
+
+	if (asprintf(&s, "DOC: %s", line) < 0) {
+		perror("asprintf");
+		exit(1);
+	}
+	consume_symbol(s);
+	free(s);
+
+	vec[0] = KERNELDOC;
+	vec[1] = DOCBOOK;
+	vec[2] = FUNCTION;
+	vec[3] = line;
+	vec[4] = filename;
+	vec[5] = NULL;
+	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
+ * 2) Lines containing !I
+ * 3) Lines containing !D
+ * 4) Lines containing !F
+ * 5) Lines containing !P
+ * 6) Lines containing !C
+ * 7) Default lines - lines not matching the above
+ */
+static void parse_file(FILE *infile)
+{
+	char line[MAXLINESZ];
+	char * s;
+	while (fgets(line, MAXLINESZ, infile)) {
+		if (line[0] == '!') {
+			s = line + 2;
+			switch (line[1]) {
+				case 'E':
+					while (*s && !isspace(*s)) s++;
+					*s = '\0';
+					externalfunctions(line+2);
+					break;
+				case 'I':
+					while (*s && !isspace(*s)) s++;
+					*s = '\0';
+					internalfunctions(line+2);
+					break;
+				case 'D':
+					while (*s && !isspace(*s)) s++;
+                                        *s = '\0';
+                                        symbolsonly(line+2);
+                                        break;
+				case 'F':
+					/* filename */
+					while (*s && !isspace(*s)) s++;
+					*s++ = '\0';
+                                        /* function names */
+					while (isspace(*s))
+						s++;
+					singlefunctions(line +2, s);
+					break;
+				case 'P':
+					/* filename */
+					while (*s && !isspace(*s)) s++;
+					*s++ = '\0';
+					/* DOC: section name */
+					while (isspace(*s))
+						s++;
+					docsection(line + 2, s);
+					break;
+				case 'C':
+					while (*s && !isspace(*s)) s++;
+					*s = '\0';
+					if (findall)
+						findall(line+2);
+					break;
+				default:
+					defaultline(line);
+			}
+		} else {
+			defaultline(line);
+		}
+	}
+	fflush(stdout);
+}
+
+
+int main(int argc, char *argv[])
+{
+	FILE * infile;
+	int i;
+
+	srctree = getenv("SRCTREE");
+	if (!srctree)
+		srctree = getcwd(NULL, 0);
+	kernsrctree = getenv("KBUILD_SRC");
+	if (!kernsrctree || !*kernsrctree)
+		kernsrctree = srctree;
+	if (argc != 3) {
+		usage();
+		exit(1);
+	}
+	/* Open file, exit on error */
+	infile = fopen(argv[2], "r");
+        if (infile == NULL) {
+                fprintf(stderr, "docproc: ");
+                perror(argv[2]);
+                exit(2);
+        }
+
+	if (strcmp("doc", argv[1]) == 0) {
+		/* Need to do this in two passes.
+		 * First pass is used to collect all symbols exported
+		 * in the various files;
+		 * Second pass generate the documentation.
+		 * This is required because some functions are declared
+		 * and exported in different files :-((
+		 */
+		/* Collect symbols */
+		defaultline       = noaction;
+		internalfunctions = find_export_symbols;
+		externalfunctions = find_export_symbols;
+		symbolsonly       = find_export_symbols;
+		singlefunctions   = noaction2;
+		docsection        = noaction2;
+		findall           = find_all_symbols;
+		parse_file(infile);
+
+		/* Rewind to start from beginning of file again */
+		fseek(infile, 0, SEEK_SET);
+		defaultline       = printline;
+		internalfunctions = intfunc;
+		externalfunctions = extfunc;
+		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) {
+		/* Create first part of dependency chain
+		 * file.tmpl */
+		printf("%s\t", argv[2]);
+		defaultline       = noaction;
+		internalfunctions = adddep;
+		externalfunctions = adddep;
+		symbolsonly       = adddep;
+		singlefunctions   = adddep2;
+		docsection        = adddep2;
+		findall           = adddep;
+		parse_file(infile);
+		printf("\n");
+	} else {
+		fprintf(stderr, "Unknown option: %s\n", argv[1]);
+		exit(1);
+	}
+	fclose(infile);
+	fflush(stdout);
+	return exitstatus;
+}