cmd/man/makewhatis.c

/*
 * Copyright (c) 2002 John Rochester
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer,
 *    in this position and unchanged.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Copyright 2012 Nexenta Systems, Inc. All rights reserved.
 * Copyright 2014 Garrett D'Amore <garrett@damore.org>
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/param.h>

#include <ctype.h>
#include <dirent.h>
#include <err.h>
#include <signal.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "man.h"
#include "stringlist.h"


/* Information collected about each man page in a section */
struct page_info {
    char    *filename;
    char    *name;
    char    *suffix;
    ino_t   inode;
};

/* An expanding string */
struct sbuf {
    char    *content;   /* the start of the buffer */
    char    *end;       /* just past the end of the content */
    char    *last;      /* the last allocated character */
};

/* Remove the last amount characters from the sbuf */
#define sbuf_retract(sbuf, amount) ((sbuf)->end -= (amount))
/* Return the length of the sbuf content */
#define sbuf_length(sbuf) ((sbuf)->end - (sbuf)->content)

typedef char *edited_copy(char *from, char *to, int length);

/*
 * While the whatis line is being formed, it is stored in whatis_proto.
 * When finished, it is reformatted into whatis_final and then appended
 * to whatis_lines.
 */
static struct sbuf  *whatis_proto;
static struct sbuf  *whatis_final;
static stringlist   *whatis_lines;  /* collected output lines */

static char tempfile[MAXPATHLEN];   /* path of temporary file, if any */

#define MDOC_COMMANDS   "ArDvErEvFlLiNmPa"


/* Free a struct page_info and its content */
static void
free_page_info(struct page_info *info)
{

    free(info->filename);
    free(info->name);
    free(info->suffix);
    free(info);
}

/*
 * Allocate and fill in a new struct page_info given the
 * name of the man section directory and the dirent of the file.
 * If the file is not a man page, return NULL.
 */
static struct page_info *
new_page_info(char *dir, struct dirent *dirent)
{
    struct page_info *info;
    int     basename_length;
    char        *suffix;
    struct stat st;

    if ((info = malloc(sizeof (struct page_info))) == NULL)
        err(1, "malloc");
    basename_length = strlen(dirent->d_name);
    suffix = &dirent->d_name[basename_length];
    if (asprintf(&info->filename, "%s/%s", dir, dirent->d_name) == -1)
        err(1, "asprintf");
    for (;;) {
        if (--suffix == dirent->d_name || !isalnum(*suffix)) {
            if (*suffix == '.')
                break;
            free(info->filename);
            free(info);
            return (NULL);
        }
    }
    *suffix++ = '\0';
    info->name = strdup(dirent->d_name);
    info->suffix = strdup(suffix);
    if (stat(info->filename, &st) < 0) {
        warn("%s", info->filename);
        free_page_info(info);
        return (NULL);
    }
    if (!S_ISREG(st.st_mode)) {
        free_page_info(info);
        return (NULL);
    }
    info->inode = st.st_ino;
    return (info);
}

/*
 * Reset sbuf length to 0.
 */
static void
sbuf_clear(struct sbuf *sbuf)
{

    sbuf->end = sbuf->content;
}

/*
 * Allocate a new sbuf.
 */
static struct sbuf *
new_sbuf(void)
{
    struct sbuf *sbuf;

    if ((sbuf = malloc(sizeof (struct sbuf))) == NULL)
        err(1, "malloc");
    if ((sbuf->content = (char *)malloc(LINE_ALLOC)) == NULL)
        err(1, "malloc");
    sbuf->last = sbuf->content + LINE_ALLOC - 1;
    sbuf_clear(sbuf);

    return (sbuf);
}

/*
 * Ensure that there is enough room in the sbuf
 * for nchars more characters.
 */
static void
sbuf_need(struct sbuf *sbuf, int nchars)
{
    char *new_content;
    size_t size, cntsize;
    size_t grow = 128;

    while (grow < nchars) {
        grow += 128;    /* we grow in chunks of 128 bytes */
    }

    /* Grow if the buffer isn't big enough */
    if (sbuf->end + nchars > sbuf->last) {
        size = sbuf->last + 1 - sbuf->content;
        size += grow;
        cntsize = sbuf->end - sbuf->content;

        if ((new_content = realloc(sbuf->content, size)) == NULL) {
            perror("realloc");
            if (tempfile[0] != '\0')
                (void) unlink(tempfile);
            exit(1);
        }
        sbuf->content = new_content;
        sbuf->end = new_content + cntsize;
        sbuf->last = new_content + size - 1;
    }
}

/*
 * Append a string of a given length to the sbuf.
 */
static void
sbuf_append(struct sbuf *sbuf, const char *text, int length)
{
    if (length > 0) {
        sbuf_need(sbuf, length);
        (void) memcpy(sbuf->end, text, length);
        sbuf->end += length;
    }
}

/*
 * Append a null-terminated string to the sbuf.
 */
static void
sbuf_append_str(struct sbuf *sbuf, char *text)
{

    sbuf_append(sbuf, text, strlen(text));
}

/*
 * Append an edited null-terminated string to the sbuf.
 */
static void
sbuf_append_edited(struct sbuf *sbuf, char *text, edited_copy copy)
{
    int length;

    if ((length = strlen(text)) > 0) {
        sbuf_need(sbuf, length);
        sbuf->end = copy(text, sbuf->end, length);
    }
}

/*
 * Strip any of a set of chars from the end of the sbuf.
 */
static void
sbuf_strip(struct sbuf *sbuf, const char *set)
{

    while (sbuf->end > sbuf->content && strchr(set, sbuf->end[-1]) != NULL)
        sbuf->end--;
}

/*
 * Return the null-terminated string built by the sbuf.
 */
static char *
sbuf_content(struct sbuf *sbuf)
{

    *sbuf->end = '\0';
    return (sbuf->content);
}

/*
 * Return true if no man page exists in the directory with
 * any of the names in the stringlist.
 */
static int
no_page_exists(char *dir, stringlist *names, char *suffix)
{
    char    path[MAXPATHLEN];
    char    *suffixes[] = { "", ".gz", ".bz2", NULL };
    size_t  i;
    int j;

    for (i = 0; i < names->sl_cur; i++) {
        for (j = 0; suffixes[j] != NULL; j++) {
            (void) snprintf(path, MAXPATHLEN, "%s/%s.%s%s",
                dir, names->sl_str[i], suffix, suffixes[j]);
            if (access(path, F_OK) == 0) {
                return (0);
            }
        }
    }
    return (1);
}

/* ARGSUSED sig */
static void
trap_signal(int sig)
{

    if (tempfile[0] != '\0')
        (void) unlink(tempfile);

    exit(1);
}

/*
 * Attempt to open an output file.
 * Return NULL if unsuccessful.
 */
static FILE *
open_output(char *name)
{
    FILE    *output;

    whatis_lines = sl_init();
    (void) snprintf(tempfile, MAXPATHLEN, "%s.tmp", name);
    name = tempfile;
    if ((output = fopen(name, "w")) == NULL) {
        warn("%s", name);
        return (NULL);
    }
    return (output);
}

static int
linesort(const void *a, const void *b)
{

    return (strcmp((*(const char * const *)a), (*(const char * const *)b)));
}

/*
 * Write the unique sorted lines to the output file.
 */
static void
finish_output(FILE *output, char *name)
{
    size_t  i;
    char    *prev = NULL;

    qsort(whatis_lines->sl_str, whatis_lines->sl_cur, sizeof (char *),
        linesort);
    for (i = 0; i < whatis_lines->sl_cur; i++) {
        char *line = whatis_lines->sl_str[i];
        if (i > 0 && strcmp(line, prev) == 0)
            continue;
        prev = line;
        (void) fputs(line, output);
        (void) putc('\n', output);
    }
    (void) fclose(output);
    sl_free(whatis_lines, 1);
    (void) rename(tempfile, name);
    (void) unlink(tempfile);
}

static FILE *
open_whatis(char *mandir)
{
    char    filename[MAXPATHLEN];

    (void) snprintf(filename, MAXPATHLEN, "%s/%s", mandir, WHATIS);
    return (open_output(filename));
}

static void
finish_whatis(FILE *output, char *mandir)
{
    char    filename[MAXPATHLEN];

    (void) snprintf(filename, MAXPATHLEN, "%s/%s", mandir, WHATIS);
    finish_output(output, filename);
}

/*
 * Remove trailing spaces from a string, returning a pointer to just
 * beyond the new last character.
 */
static char *
trim_rhs(char *str)
{
    char    *rhs;

    rhs = &str[strlen(str)];
    while (--rhs > str && isspace(*rhs))
        ;
    *++rhs = '\0';
    return (rhs);
}

/*
 * Return a pointer to the next non-space character in the string.
 */
static char *
skip_spaces(char *s)
{

    while (*s != '\0' && isspace(*s))
        s++;

    return (s);
}

/*
 * Return whether the line is of one of the forms:
 *  .Sh NAME
 *  .Sh "NAME"
 *  etc.
 * assuming that section_start is ".Sh".
 */
static int
name_section_line(char *line, const char *section_start)
{
    char        *rhs;

    if (strncmp(line, section_start, 3) != 0)
        return (0);
    line = skip_spaces(line + 3);
    rhs = trim_rhs(line);
    if (*line == '"') {
        line++;
        if (*--rhs == '"')
            *rhs = '\0';
    }
    if (strcmp(line, "NAME") == 0)
        return (1);

    return (0);
}

/*
 * Copy characters while removing the most common nroff/troff markup:
 *  \(em, \(mi, \s[+-N], \&
 *  \fF, \f(fo, \f[font]
 *  \*s, \*(st, \*[stringvar]
 */
static char *
de_nroff_copy(char *from, char *to, int fromlen)
{
    char    *from_end = &from[fromlen];

    while (from < from_end) {
        switch (*from) {
        case '\\':
            switch (*++from) {
            case '(':
                if (strncmp(&from[1], "em", 2) == 0 ||
                    strncmp(&from[1], "mi", 2) == 0) {
                    from += 3;
                    continue;
                }
                break;
            case 's':
                if (*++from == '-')
                    from++;
                while (isdigit(*from))
                    from++;
                continue;
            case 'f':
            case '*':
                if (*++from == '(') {
                    from += 3;
                } else if (*from == '[') {
                    while (*++from != ']' &&
                        from < from_end)
                        ;
                    from++;
                } else {
                    from++;
                }
                continue;
            case '&':
                from++;
                continue;
            }
            break;
        }
        *to++ = *from++;
    }
    return (to);
}

/*
 * Append a string with the nroff formatting removed.
 */
static void
add_nroff(char *text)
{

    sbuf_append_edited(whatis_proto, text, de_nroff_copy);
}

/*
 * Appends "name(suffix), " to whatis_final
 */
static void
add_whatis_name(char *name, char *suffix)
{

    if (*name != '\0') {
        sbuf_append_str(whatis_final, name);
        sbuf_append(whatis_final, "(", 1);
        sbuf_append_str(whatis_final, suffix);
        sbuf_append(whatis_final, "), ", 3);
    }
}

/*
 * Processes an old-style man(7) line. This ignores commands with only
 * a single number argument.
 */
static void
process_man_line(char *line)
{
    char    *p;

    if (*line == '.') {
        while (isalpha(*++line))
            ;
        p = line = skip_spaces(line);
        while (*p != '\0') {
            if (!isdigit(*p))
                break;
            p++;
        }
        if (*p == '\0')
            return;
    } else
        line = skip_spaces(line);
    if (*line != '\0') {
        add_nroff(line);
        sbuf_append(whatis_proto, " ", 1);
    }
}

/*
 * Processes a new-style mdoc(7) line.
 */
static void
process_mdoc_line(char *line)
{
    int xref;
    int arg = 0;
    char    *line_end = &line[strlen(line)];
    int orig_length = sbuf_length(whatis_proto);
    char    *next;

    if (*line == '\0')
        return;
    if (line[0] != '.' || !isupper(line[1]) || !islower(line[2])) {
        add_nroff(skip_spaces(line));
        sbuf_append(whatis_proto, " ", 1);
        return;
    }
    xref = strncmp(line, ".Xr", 3) == 0;
    line += 3;
    while ((line = skip_spaces(line)) < line_end) {
        if (*line == '"') {
            next = ++line;
            for (;;) {
                next = strchr(next, '"');
                if (next == NULL)
                    break;
                (void) memmove(next, next + 1, strlen(next));
                line_end--;
                if (*next != '"')
                    break;
                next++;
            }
        } else {
            next = strpbrk(line, " \t");
        }
        if (next != NULL)
            *next++ = '\0';
        else
            next = line_end;
        if (isupper(*line) && islower(line[1]) && line[2] == '\0') {
            if (strcmp(line, "Ns") == 0) {
                arg = 0;
                line = next;
                continue;
            }
            if (strstr(line, MDOC_COMMANDS) != NULL) {
                line = next;
                continue;
            }
        }
        if (arg > 0 && strchr(",.:;?!)]", *line) == 0) {
            if (xref) {
                sbuf_append(whatis_proto, "(", 1);
                add_nroff(line);
                sbuf_append(whatis_proto, ")", 1);
                xref = 0;
            } else {
                sbuf_append(whatis_proto, " ", 1);
            }
        }
        add_nroff(line);
        arg++;
        line = next;
    }
    if (sbuf_length(whatis_proto) > orig_length)
        sbuf_append(whatis_proto, " ", 1);
}

/*
 * Collect a list of comma-separated names from the text.
 */
static void
collect_names(stringlist *names, char *text)
{
    char    *arg;

    for (;;) {
        arg = text;
        text = strchr(text, ',');
        if (text != NULL)
            *text++ = '\0';
        (void) sl_add(names, arg);
        if (text == NULL)
            return;
        if (*text == ' ')
            text++;
    }
}

enum { STATE_UNKNOWN, STATE_MANSTYLE, STATE_MDOCNAME, STATE_MDOCDESC };

/*
 * Process a man page source into a single whatis line and add it
 * to whatis_lines.
 */
static void
process_page(struct page_info *page, char *section_dir)
{
    FILE        *fp;
    stringlist  *names;
    char        *descr;
    int     state = STATE_UNKNOWN;
    size_t      i;
    char        *line = NULL;
    size_t      linecap = 0;

    sbuf_clear(whatis_proto);
    if ((fp = fopen(page->filename, "r")) == NULL) {
        warn("%s", page->filename);
        return;
    }
    while (getline(&line, &linecap, fp) > 0) {
        /* Skip comments */
        if (strncmp(line, ".\\\"", 3) == 0)
            continue;
        switch (state) {
        /* Haven't reached the NAME section yet */
        case STATE_UNKNOWN:
            if (name_section_line(line, ".SH"))
                state = STATE_MANSTYLE;
            else if (name_section_line(line, ".Sh"))
                state = STATE_MDOCNAME;
            continue;
        /* Inside an old-style .SH NAME section */
        case STATE_MANSTYLE:
            if (strncmp(line, ".SH", 3) == 0 ||
                strncmp(line, ".SS", 3) == 0)
                break;
            (void) trim_rhs(line);
            if (strcmp(line, ".") == 0)
                continue;
            if (strncmp(line, ".IX", 3) == 0) {
                line += 3;
                line = skip_spaces(line);
            }
            process_man_line(line);
            continue;
        /* Inside a new-style .Sh NAME section (the .Nm part) */
        case STATE_MDOCNAME:
            (void) trim_rhs(line);
            if (strncmp(line, ".Nm", 3) == 0) {
                process_mdoc_line(line);
                continue;
            } else {
                if (strcmp(line, ".") == 0)
                    continue;
                sbuf_append(whatis_proto, "- ", 2);
                state = STATE_MDOCDESC;
            }
            /* FALLTHROUGH */
        /* Inside a new-style .Sh NAME section (after the .Nm-s) */
        case STATE_MDOCDESC:
            if (strncmp(line, ".Sh", 3) == 0)
                break;
            (void) trim_rhs(line);
            if (strcmp(line, ".") == 0)
                continue;
            process_mdoc_line(line);
            continue;
        }
        break;
    }
    (void) fclose(fp);
    sbuf_strip(whatis_proto, " \t.-");
    line = sbuf_content(whatis_proto);
    /*
     * Line now contains the appropriate data, but without the
     * proper indentation or the section appended to each name.
     */
    descr = strstr(line, " - ");
    if (descr == NULL) {
        descr = strchr(line, ' ');
        if (descr == NULL)
            return;
        *descr++ = '\0';
    } else {
        *descr = '\0';
        descr += 3;
    }
    names = sl_init();
    collect_names(names, line);
    sbuf_clear(whatis_final);
    if (!sl_find(names, page->name) &&
        no_page_exists(section_dir, names, page->suffix)) {
        /*
         * Add the page name since that's the only
         * thing that man(1) will find.
         */
        add_whatis_name(page->name, page->suffix);
    }
    for (i = 0; i < names->sl_cur; i++)
        add_whatis_name(names->sl_str[i], page->suffix);
    sl_free(names, 0);
    /* Remove last ", " */
    sbuf_retract(whatis_final, 2);
    while (sbuf_length(whatis_final) < INDENT)
        sbuf_append(whatis_final, " ", 1);
    sbuf_append(whatis_final, " - ", 3);
    sbuf_append_str(whatis_final, skip_spaces(descr));
    (void) sl_add(whatis_lines, strdup(sbuf_content(whatis_final)));
}

/*
 * Sort pages first by inode number, then by name.
 */
static int
pagesort(const void *a, const void *b)
{
    const struct page_info *p1 = *(struct page_info * const *) a;
    const struct page_info *p2 = *(struct page_info * const *) b;

    if (p1->inode == p2->inode)
        return (strcmp(p1->name, p2->name));

    return (p1->inode - p2->inode);
}

/*
 * Process a single man section.
 */
static void
process_section(char *section_dir)
{
    struct dirent   **entries;
    int     nentries;
    struct page_info **pages;
    int     npages = 0;
    int     i;
    ino_t       prev_inode = 0;

    /* Scan the man section directory for pages */
    nentries = scandir(section_dir, &entries, NULL, alphasort);

    /* Collect information about man pages */
    pages = (struct page_info **)calloc(nentries,
        sizeof (struct page_info *));
    for (i = 0; i < nentries; i++) {
        struct page_info *info = new_page_info(section_dir, entries[i]);
        if (info != NULL)
            pages[npages++] = info;
        free(entries[i]);
    }
    free(entries);
    qsort(pages, npages, sizeof (struct page_info *), pagesort);

    /* Process each unique page */
    for (i = 0; i < npages; i++) {
        struct page_info *page = pages[i];
        if (page->inode != prev_inode) {
            prev_inode = page->inode;
            process_page(page, section_dir);
        }
        free_page_info(page);
    }
    free(pages);
}

/*
 * Return whether the directory entry is a man page section.
 */
static int
select_sections(const struct dirent *entry)
{
    const char  *p = &entry->d_name[3];

    if (strncmp(entry->d_name, "man", 3) != 0)
        return (0);
    while (*p != '\0') {
        if (!isalnum(*p++))
            return (0);
    }
    return (1);
}

/*
 * Process a single top-level man directory by finding all the
 * sub-directories named man* and processing each one in turn.
 */
void
mwpath(char *path)
{
    FILE        *fp = NULL;
    struct dirent   **entries;
    int     nsections;
    int     i;

    (void) signal(SIGINT, trap_signal);
    (void) signal(SIGHUP, trap_signal);
    (void) signal(SIGQUIT, trap_signal);
    (void) signal(SIGTERM, trap_signal);

    whatis_proto = new_sbuf();
    whatis_final = new_sbuf();

    nsections = scandir(path, &entries, select_sections, alphasort);
    if ((fp = open_whatis(path)) == NULL)
        return;
    for (i = 0; i < nsections; i++) {
        char    section_dir[MAXPATHLEN];

        (void) snprintf(section_dir, MAXPATHLEN, "%s/%s",
            path, entries[i]->d_name);
        process_section(section_dir);
        free(entries[i]);
    }
    free(entries);
    finish_whatis(fp, path);
}