source: MondoRescue/branches/stable/mindi-busybox/findutils/grep.c@ 1770

/* vi: set sw=4 ts=4: */
/*
 * Mini grep implementation for busybox using libc regex.
 *
 * Copyright (C) 1999,2000,2001 by Lineo, inc. and Mark Whitley
 * Copyright (C) 1999,2000,2001 by Mark Whitley <markw@codepoet.org>
 *
 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
 */
/* BB_AUDIT SUSv3 defects - unsupported option -x.  */
/* BB_AUDIT GNU defects - always acts as -a.  */
/* http://www.opengroup.org/onlinepubs/007904975/utilities/grep.html */
/*
 * 2004,2006 (C) Vladimir Oleynik <dzo@simtreas.ru> -
 * correction "-e pattern1 -e pattern2" logic and more optimizations.
 * precompiled regex
 */
/*
 * (C) 2006 Jac Goudsmit added -o option
 */

#include "libbb.h"
#include "xregex.h"

/* options */
#define OPTSTR_GREP \
    "lnqvscFiHhe:f:Lorm:" \
    USE_FEATURE_GREP_CONTEXT("A:B:C:") \
    USE_FEATURE_GREP_EGREP_ALIAS("E") \
    USE_DESKTOP("w") \
    "aI"
/* ignored: -a "assume all files to be text" */
/* ignored: -I "assume binary files have no matches" */

enum {
    OPTBIT_l, /* list matched file names only */
    OPTBIT_n, /* print line# */
    OPTBIT_q, /* quiet - exit(0) of first match */
    OPTBIT_v, /* invert the match, to select non-matching lines */
    OPTBIT_s, /* suppress errors about file open errors */
    OPTBIT_c, /* count matches per file (suppresses normal output) */
    OPTBIT_F, /* literal match */
    OPTBIT_i, /* case-insensitive */
    OPTBIT_H, /* force filename display */
    OPTBIT_h, /* inhibit filename display */
    OPTBIT_e, /* -e PATTERN */
    OPTBIT_f, /* -f FILE_WITH_PATTERNS */
    OPTBIT_L, /* list unmatched file names only */
    OPTBIT_o, /* show only matching parts of lines */
    OPTBIT_r, /* recurse dirs */
    OPTBIT_m, /* -m MAX_MATCHES */
    USE_FEATURE_GREP_CONTEXT(    OPTBIT_A ,) /* -A NUM: after-match context */
    USE_FEATURE_GREP_CONTEXT(    OPTBIT_B ,) /* -B NUM: before-match context */
    USE_FEATURE_GREP_CONTEXT(    OPTBIT_C ,) /* -C NUM: -A and -B combined */
    USE_FEATURE_GREP_EGREP_ALIAS(OPTBIT_E ,) /* extended regexp */
    USE_DESKTOP(                 OPTBIT_w ,) /* whole word match */
    OPT_l = 1 << OPTBIT_l,
    OPT_n = 1 << OPTBIT_n,
    OPT_q = 1 << OPTBIT_q,
    OPT_v = 1 << OPTBIT_v,
    OPT_s = 1 << OPTBIT_s,
    OPT_c = 1 << OPTBIT_c,
    OPT_F = 1 << OPTBIT_F,
    OPT_i = 1 << OPTBIT_i,
    OPT_H = 1 << OPTBIT_H,
    OPT_h = 1 << OPTBIT_h,
    OPT_e = 1 << OPTBIT_e,
    OPT_f = 1 << OPTBIT_f,
    OPT_L = 1 << OPTBIT_L,
    OPT_o = 1 << OPTBIT_o,
    OPT_r = 1 << OPTBIT_r,
    OPT_m = 1 << OPTBIT_m,
    OPT_A = USE_FEATURE_GREP_CONTEXT(    (1 << OPTBIT_A)) + 0,
    OPT_B = USE_FEATURE_GREP_CONTEXT(    (1 << OPTBIT_B)) + 0,
    OPT_C = USE_FEATURE_GREP_CONTEXT(    (1 << OPTBIT_C)) + 0,
    OPT_E = USE_FEATURE_GREP_EGREP_ALIAS((1 << OPTBIT_E)) + 0,
    OPT_w = USE_DESKTOP(                 (1 << OPTBIT_w)) + 0,
};

#define PRINT_FILES_WITH_MATCHES    (option_mask32 & OPT_l)
#define PRINT_LINE_NUM              (option_mask32 & OPT_n)
#define BE_QUIET                    (option_mask32 & OPT_q)
#define SUPPRESS_ERR_MSGS           (option_mask32 & OPT_s)
#define PRINT_MATCH_COUNTS          (option_mask32 & OPT_c)
#define FGREP_FLAG                  (option_mask32 & OPT_F)
#define PRINT_FILES_WITHOUT_MATCHES (option_mask32 & OPT_L)

typedef unsigned char byte_t;

static int max_matches;
static int reflags;
static byte_t invert_search;
static byte_t print_filename;
static byte_t open_errors;

#if ENABLE_FEATURE_GREP_CONTEXT
static byte_t did_print_line;
static int lines_before;
static int lines_after;
static char **before_buf;
static int last_line_printed;
#endif /* ENABLE_FEATURE_GREP_CONTEXT */
/* globals used internally */
static llist_t *pattern_head;   /* growable list of patterns to match */
static const char *cur_file;    /* the current file we are reading */

typedef struct grep_list_data_t {
    char *pattern;
    regex_t preg;
#define PATTERN_MEM_A 1
#define COMPILED 2
    int flg_mem_alocated_compiled;
} grep_list_data_t;

static void print_line(const char *line, int linenum, char decoration)
{
#if ENABLE_FEATURE_GREP_CONTEXT
    /* Happens when we go to next file, immediately hit match
     * and try to print prev context... from prev file! Don't do it */
    if (linenum < 1)
        return;
    /* possibly print the little '--' separator */
    if ((lines_before || lines_after) && did_print_line &&
            last_line_printed != linenum - 1) {
        puts("--");
    }
    /* guard against printing "--" before first line of first file */
    did_print_line = 1;
    last_line_printed = linenum;
#endif
    if (print_filename)
        printf("%s%c", cur_file, decoration);
    if (PRINT_LINE_NUM)
        printf("%i%c", linenum, decoration);
    /* Emulate weird GNU grep behavior with -ov */
    if ((option_mask32 & (OPT_v|OPT_o)) != (OPT_v|OPT_o))
        puts(line);
}

static int grep_file(FILE *file)
{
    char *line;
    byte_t ret;
    int linenum = 0;
    int nmatches = 0;
    regmatch_t regmatch;
#if ENABLE_FEATURE_GREP_CONTEXT
    int print_n_lines_after = 0;
    int curpos = 0; /* track where we are in the circular 'before' buffer */
    int idx = 0; /* used for iteration through the circular buffer */
#else
    enum { print_n_lines_after = 0 };
#endif /* ENABLE_FEATURE_GREP_CONTEXT */

    while ((line = xmalloc_getline(file)) != NULL) {
        llist_t *pattern_ptr = pattern_head;
        grep_list_data_t * gl;

        linenum++;
        ret = 0;
        while (pattern_ptr) {
            gl = (grep_list_data_t *)pattern_ptr->data;
            if (FGREP_FLAG) {
                ret = strstr(line, gl->pattern) != NULL;
            } else {
                /*
                 * test for a postitive-assertion match (regexec returns success (0)
                 * and the user did not specify invert search), or a negative-assertion
                 * match (regexec returns failure (REG_NOMATCH) and the user specified
                 * invert search)
                 */
                if (!(gl->flg_mem_alocated_compiled & COMPILED)) {
                    gl->flg_mem_alocated_compiled |= COMPILED;
                    xregcomp(&(gl->preg), gl->pattern, reflags);
                }
                regmatch.rm_so = 0;
                regmatch.rm_eo = 0;
                if (regexec(&(gl->preg), line, 1, &regmatch, 0) == 0) {
                    if (!(option_mask32 & OPT_w))
                        ret = 1;
                    else {
                        char c = ' ';
                        if (regmatch.rm_so)
                            c = line[regmatch.rm_so - 1];
                        if (!isalnum(c) && c != '_') {
                            c = line[regmatch.rm_eo];
                            if (!c || (!isalnum(c) && c != '_'))
                                ret = 1;
                        }
                    }
                }
            }
            pattern_ptr = pattern_ptr->link;
        } /* while (pattern_ptr) */

        if (ret ^ invert_search) {
            /* keep track of matches */
            nmatches++;

            /* quiet/print (non)matching file names only? */
            if (option_mask32 & (OPT_q|OPT_l|OPT_L)) {
                free(line); /* we don't need line anymore */
                if (BE_QUIET) {
                    /* manpage says about -q:
                     * "exit immediately with zero status
                     * if any match is found,
                     * even if errors were detected" */
                    exit(0);
                }
                /* if we're just printing filenames, we stop after the first match */
                if (PRINT_FILES_WITH_MATCHES) {
                    puts(cur_file);
                    /* fall thru to "return 1" */
                }
                /* OPT_L aka PRINT_FILES_WITHOUT_MATCHES: return early */
                return 1; /* one match */
            }

#if ENABLE_FEATURE_GREP_CONTEXT
            /* Were we printing context and saw next (unwanted) match? */
            if ((option_mask32 & OPT_m) && nmatches > max_matches)
                break;
#endif

            /* print the matched line */
            if (PRINT_MATCH_COUNTS == 0) {
#if ENABLE_FEATURE_GREP_CONTEXT
                int prevpos = (curpos == 0) ? lines_before - 1 : curpos - 1;

                /* if we were told to print 'before' lines and there is at least
                 * one line in the circular buffer, print them */
                if (lines_before && before_buf[prevpos] != NULL) {
                    int first_buf_entry_line_num = linenum - lines_before;

                    /* advance to the first entry in the circular buffer, and
                     * figure out the line number is of the first line in the
                     * buffer */
                    idx = curpos;
                    while (before_buf[idx] == NULL) {
                        idx = (idx + 1) % lines_before;
                        first_buf_entry_line_num++;
                    }

                    /* now print each line in the buffer, clearing them as we go */
                    while (before_buf[idx] != NULL) {
                        print_line(before_buf[idx], first_buf_entry_line_num, '-');
                        free(before_buf[idx]);
                        before_buf[idx] = NULL;
                        idx = (idx + 1) % lines_before;
                        first_buf_entry_line_num++;
                    }
                }

                /* make a note that we need to print 'after' lines */
                print_n_lines_after = lines_after;
#endif
                if (option_mask32 & OPT_o) {
                    line[regmatch.rm_eo] = '\0';
                    print_line(line + regmatch.rm_so, linenum, ':');
                } else {
                    print_line(line, linenum, ':');
                }
            }
        }
#if ENABLE_FEATURE_GREP_CONTEXT
        else { /* no match */
            /* if we need to print some context lines after the last match, do so */
            if (print_n_lines_after) {
                print_line(line, linenum, '-');
                print_n_lines_after--;
            } else if (lines_before) {
                /* Add the line to the circular 'before' buffer */
                free(before_buf[curpos]);
                before_buf[curpos] = line;
                curpos = (curpos + 1) % lines_before;
                /* avoid free(line) - we took line */
                line = NULL;
            }
        }

#endif /* ENABLE_FEATURE_GREP_CONTEXT */
        free(line);

        /* Did we print all context after last requested match? */
        if ((option_mask32 & OPT_m)
         && !print_n_lines_after && nmatches == max_matches)
            break;
    }

    /* special-case file post-processing for options where we don't print line
     * matches, just filenames and possibly match counts */

    /* grep -c: print [filename:]count, even if count is zero */
    if (PRINT_MATCH_COUNTS) {
        if (print_filename)
            printf("%s:", cur_file);
        printf("%d\n", nmatches);
    }

    /* grep -L: print just the filename */
    if (PRINT_FILES_WITHOUT_MATCHES) {
        /* nmatches is zero, no need to check it:
         * we return 1 early if we detected a match
         * and PRINT_FILES_WITHOUT_MATCHES is set */
        puts(cur_file);
    }

    return nmatches;
}

#if ENABLE_FEATURE_CLEAN_UP
#define new_grep_list_data(p, m) add_grep_list_data(p, m)
static char * add_grep_list_data(char *pattern, int flg_used_mem)
#else
#define new_grep_list_data(p, m) add_grep_list_data(p)
static char * add_grep_list_data(char *pattern)
#endif
{
    grep_list_data_t *gl = xmalloc(sizeof(grep_list_data_t));
    gl->pattern = pattern;
#if ENABLE_FEATURE_CLEAN_UP
    gl->flg_mem_alocated_compiled = flg_used_mem;
#else
    gl->flg_mem_alocated_compiled = 0;
#endif
    return (char *)gl;
}

static void load_regexes_from_file(llist_t *fopt)
{
    char *line;
    FILE *f;

    while (fopt) {
        llist_t *cur = fopt;
        char *ffile = cur->data;

        fopt = cur->link;
        free(cur);
        f = xfopen(ffile, "r");
        while ((line = xmalloc_getline(f)) != NULL) {
            llist_add_to(&pattern_head,
                new_grep_list_data(line, PATTERN_MEM_A));
        }
    }
}

static int file_action_grep(const char *filename, struct stat *statbuf, void* matched, int depth)
{
    FILE *file = fopen(filename, "r");
    if (file == NULL) {
        if (!SUPPRESS_ERR_MSGS)
            bb_perror_msg("%s", cur_file);
        open_errors = 1;
        return 0;
    }
    cur_file = filename;
    *(int*)matched += grep_file(file);
    fclose(file);
    return 1;
}

static int grep_dir(const char *dir)
{
    int matched = 0;
    recursive_action(dir,
        /* recurse=yes */ ACTION_RECURSE |
        /* followLinks=no */
        /* depthFirst=yes */ ACTION_DEPTHFIRST,
        /* fileAction= */ file_action_grep,
        /* dirAction= */ NULL,
        /* userData= */ &matched,
        /* depth= */ 0);
    return matched;
}

int grep_main(int argc, char **argv);
int grep_main(int argc, char **argv)
{
    FILE *file;
    int matched;
    char *mopt;
    llist_t *fopt = NULL;

    /* do normal option parsing */
#if ENABLE_FEATURE_GREP_CONTEXT
    char *slines_after;
    char *slines_before;
    char *Copt;

    opt_complementary = "H-h:e::f::C-AB";
    getopt32(argv,
        OPTSTR_GREP,
        &pattern_head, &fopt, &mopt,
        &slines_after, &slines_before, &Copt);

    if (option_mask32 & OPT_C) {
        /* -C unsets prev -A and -B, but following -A or -B
           may override it */
        if (!(option_mask32 & OPT_A)) /* not overridden */
            slines_after = Copt;
        if (!(option_mask32 & OPT_B)) /* not overridden */
            slines_before = Copt;
        option_mask32 |= OPT_A|OPT_B; /* for parser */
    }
    if (option_mask32 & OPT_A) {
        lines_after = xatoi_u(slines_after);
    }
    if (option_mask32 & OPT_B) {
        lines_before = xatoi_u(slines_before);
    }
    /* sanity checks */
    if (option_mask32 & (OPT_c|OPT_q|OPT_l|OPT_L)) {
        option_mask32 &= ~OPT_n;
        lines_before = 0;
        lines_after = 0;
    } else if (lines_before > 0)
        before_buf = xzalloc(lines_before * sizeof(char *));
#else
    /* with auto sanity checks */
    opt_complementary = "H-h:e::f::c-n:q-n:l-n";
    getopt32(argv, OPTSTR_GREP,
        &pattern_head, &fopt, &mopt);
#endif
    if (option_mask32 & OPT_m) {
        max_matches = xatoi_u(mopt);
    }
    invert_search = ((option_mask32 & OPT_v) != 0); /* 0 | 1 */

    if (pattern_head != NULL) {
        /* convert char **argv to grep_list_data_t */
        llist_t *cur;

        for (cur = pattern_head; cur; cur = cur->link)
            cur->data = new_grep_list_data(cur->data, 0);
    }
    if (option_mask32 & OPT_f)
        load_regexes_from_file(fopt);

    if (ENABLE_FEATURE_GREP_FGREP_ALIAS && applet_name[0] == 'f')
        option_mask32 |= OPT_F;

    if (!(option_mask32 & (OPT_o | OPT_w)))
        reflags = REG_NOSUB;

    if (ENABLE_FEATURE_GREP_EGREP_ALIAS &&
            (applet_name[0] == 'e' || (option_mask32 & OPT_E)))
        reflags |= REG_EXTENDED;

    if (option_mask32 & OPT_i)
        reflags |= REG_ICASE;

    argv += optind;
    argc -= optind;

    /* if we didn't get a pattern from a -e and no command file was specified,
     * argv[optind] should be the pattern. no pattern, no worky */
    if (pattern_head == NULL) {
        char *pattern;
        if (*argv == NULL)
            bb_show_usage();
        pattern = new_grep_list_data(*argv++, 0);
        llist_add_to(&pattern_head, pattern);
        argc--;
    }

    /* argv[(optind)..(argc-1)] should be names of file to grep through. If
     * there is more than one file to grep, we will print the filenames. */
    if (argc > 1)
        print_filename = 1;
    /* -H / -h of course override */
    if (option_mask32 & OPT_H)
        print_filename = 1;
    if (option_mask32 & OPT_h)
        print_filename = 0;

    /* If no files were specified, or '-' was specified, take input from
     * stdin. Otherwise, we grep through all the files specified. */
    if (argc == 0)
        argc++;
    matched = 0;
    while (argc--) {
        cur_file = *argv++;
        file = stdin;
        if (!cur_file || (*cur_file == '-' && !cur_file[1])) {
            cur_file = "(standard input)";
        } else {
            if (option_mask32 & OPT_r) {
                struct stat st;
                if (stat(cur_file, &st) == 0 && S_ISDIR(st.st_mode)) {
                    if (!(option_mask32 & OPT_h))
                        print_filename = 1;
                    matched += grep_dir(cur_file);
                    goto grep_done;
                }
            }
            /* else: fopen(dir) will succeed, but reading won't */
            file = fopen(cur_file, "r");
            if (file == NULL) {
                if (!SUPPRESS_ERR_MSGS)
                    bb_perror_msg("%s", cur_file);
                open_errors = 1;
                continue;
            }
        }
        matched += grep_file(file);
        fclose_if_not_stdin(file);
 grep_done: ;
    }

    /* destroy all the elments in the pattern list */
    if (ENABLE_FEATURE_CLEAN_UP) {
        while (pattern_head) {
            llist_t *pattern_head_ptr = pattern_head;
            grep_list_data_t *gl =
                (grep_list_data_t *)pattern_head_ptr->data;

            pattern_head = pattern_head->link;
            if ((gl->flg_mem_alocated_compiled & PATTERN_MEM_A))
                free(gl->pattern);
            if ((gl->flg_mem_alocated_compiled & COMPILED))
                regfree(&(gl->preg));
            free(gl);
            free(pattern_head_ptr);
        }
    }
    /* 0 = success, 1 = failed, 2 = error */
    if (open_errors)
        return 2;
    return !matched; /* invert return value 0 = success, 1 = failed */
}