docproc.c

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/*
 *  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 "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)
{
    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;
}