Bump to version 1.22.1
[platform/upstream/busybox.git] / findutils / grep.c
index e1ce8e5..a7bc4ca 100644 (file)
  * 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, see the file LICENSE in this tarball.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
-/* BB_AUDIT SUSv3 defects - unsupported option -x */
+/* BB_AUDIT SUSv3 defects - unsupported option -x "match whole line only". */
 /* 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
-*/
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <getopt.h>
-#include <string.h>
-#include <errno.h>
-#include "busybox.h"
+ *
+ * (C) 2006 Jac Goudsmit added -o option
+ */
+
+//applet:IF_GREP(APPLET(grep, BB_DIR_BIN, BB_SUID_DROP))
+//applet:IF_FEATURE_GREP_EGREP_ALIAS(APPLET_ODDNAME(egrep, grep, BB_DIR_BIN, BB_SUID_DROP, egrep))
+//applet:IF_FEATURE_GREP_FGREP_ALIAS(APPLET_ODDNAME(fgrep, grep, BB_DIR_BIN, BB_SUID_DROP, fgrep))
+
+//kbuild:lib-$(CONFIG_GREP) += grep.o
+
+//config:config GREP
+//config:      bool "grep"
+//config:      default y
+//config:      help
+//config:        grep is used to search files for a specified pattern.
+//config:
+//config:config FEATURE_GREP_EGREP_ALIAS
+//config:      bool "Enable extended regular expressions (egrep & grep -E)"
+//config:      default y
+//config:      depends on GREP
+//config:      help
+//config:        Enabled support for extended regular expressions. Extended
+//config:        regular expressions allow for alternation (foo|bar), grouping,
+//config:        and various repetition operators.
+//config:
+//config:config FEATURE_GREP_FGREP_ALIAS
+//config:      bool "Alias fgrep to grep -F"
+//config:      default y
+//config:      depends on GREP
+//config:      help
+//config:        fgrep sees the search pattern as a normal string rather than
+//config:        regular expressions.
+//config:        grep -F always works, this just creates the fgrep alias.
+//config:
+//config:config FEATURE_GREP_CONTEXT
+//config:      bool "Enable before and after context flags (-A, -B and -C)"
+//config:      default y
+//config:      depends on GREP
+//config:      help
+//config:        Print the specified number of leading (-B) and/or trailing (-A)
+//config:        context surrounding our matching lines.
+//config:        Print the specified number of context lines (-C).
+
+#include "libbb.h"
 #include "xregex.h"
 
 
 /* options */
-static unsigned long opt;
-#define GREP_OPTS "lnqvscFiHhe:f:L"
-#define GREP_OPT_l (1<<0)
-#define PRINT_FILES_WITH_MATCHES (opt & GREP_OPT_l)
-#define GREP_OPT_n (1<<1)
-#define PRINT_LINE_NUM (opt & GREP_OPT_n)
-#define GREP_OPT_q (1<<2)
-#define BE_QUIET (opt & GREP_OPT_q)
-#define GREP_OPT_v (1<<3)
-typedef char invert_search_t;
-static invert_search_t invert_search;
-#define GREP_OPT_s (1<<4)
-#define SUPPRESS_ERR_MSGS (opt & GREP_OPT_s)
-#define GREP_OPT_c (1<<5)
-#define PRINT_MATCH_COUNTS (opt & GREP_OPT_c)
-#define GREP_OPT_F (1<<6)
-#define FGREP_FLAG (opt & GREP_OPT_F)
-#define GREP_OPT_i (1<<7)
-#define GREP_OPT_H (1<<8)
-#define GREP_OPT_h (1<<9)
-#define GREP_OPT_e (1<<10)
-#define GREP_OPT_f (1<<11)
-#define GREP_OPT_L (1<<12)
-#define PRINT_FILES_WITHOUT_MATCHES ((opt & GREP_OPT_L) != 0)
-#if ENABLE_FEATURE_GREP_CONTEXT
-#define GREP_OPT_CONTEXT "A:B:C"
-#define GREP_OPT_A (1<<13)
-#define GREP_OPT_B (1<<14)
-#define GREP_OPT_C (1<<15)
-#define GREP_OPT_E (1<<16)
+//usage:#define grep_trivial_usage
+//usage:       "[-HhnlLoqvsriw"
+//usage:       "F"
+//usage:       IF_FEATURE_GREP_EGREP_ALIAS("E")
+//usage:       IF_EXTRA_COMPAT("z")
+//usage:       "] [-m N] "
+//usage:       IF_FEATURE_GREP_CONTEXT("[-A/B/C N] ")
+//usage:       "PATTERN/-e PATTERN.../-f FILE [FILE]..."
+//usage:#define grep_full_usage "\n\n"
+//usage:       "Search for PATTERN in FILEs (or stdin)\n"
+//usage:     "\n       -H      Add 'filename:' prefix"
+//usage:     "\n       -h      Do not add 'filename:' prefix"
+//usage:     "\n       -n      Add 'line_no:' prefix"
+//usage:     "\n       -l      Show only names of files that match"
+//usage:     "\n       -L      Show only names of files that don't match"
+//usage:     "\n       -c      Show only count of matching lines"
+//usage:     "\n       -o      Show only the matching part of line"
+//usage:     "\n       -q      Quiet. Return 0 if PATTERN is found, 1 otherwise"
+//usage:     "\n       -v      Select non-matching lines"
+//usage:     "\n       -s      Suppress open and read errors"
+//usage:     "\n       -r      Recurse"
+//usage:     "\n       -i      Ignore case"
+//usage:     "\n       -w      Match whole words only"
+//usage:     "\n       -x      Match whole lines only"
+//usage:     "\n       -F      PATTERN is a literal (not regexp)"
+//usage:       IF_FEATURE_GREP_EGREP_ALIAS(
+//usage:     "\n       -E      PATTERN is an extended regexp"
+//usage:       )
+//usage:       IF_EXTRA_COMPAT(
+//usage:     "\n       -z      Input is NUL terminated"
+//usage:       )
+//usage:     "\n       -m N    Match up to N times per file"
+//usage:       IF_FEATURE_GREP_CONTEXT(
+//usage:     "\n       -A N    Print N lines of trailing context"
+//usage:     "\n       -B N    Print N lines of leading context"
+//usage:     "\n       -C N    Same as '-A N -B N'"
+//usage:       )
+//usage:     "\n       -e PTRN Pattern to match"
+//usage:     "\n       -f FILE Read pattern from file"
+//usage:
+//usage:#define grep_example_usage
+//usage:       "$ grep root /etc/passwd\n"
+//usage:       "root:x:0:0:root:/root:/bin/bash\n"
+//usage:       "$ grep ^[rR]oo. /etc/passwd\n"
+//usage:       "root:x:0:0:root:/root:/bin/bash\n"
+//usage:
+//usage:#define egrep_trivial_usage NOUSAGE_STR
+//usage:#define egrep_full_usage ""
+//usage:#define fgrep_trivial_usage NOUSAGE_STR
+//usage:#define fgrep_full_usage ""
+
+#define OPTSTR_GREP \
+       "lnqvscFiHhe:f:Lorm:wx" \
+       IF_FEATURE_GREP_CONTEXT("A:B:C:") \
+       IF_FEATURE_GREP_EGREP_ALIAS("E") \
+       IF_EXTRA_COMPAT("z") \
+       "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(EXIT_SUCCESS) 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 */
+       OPTBIT_w, /* -w whole word match */
+       OPTBIT_x, /* -x whole line match */
+       IF_FEATURE_GREP_CONTEXT(    OPTBIT_A ,) /* -A NUM: after-match context */
+       IF_FEATURE_GREP_CONTEXT(    OPTBIT_B ,) /* -B NUM: before-match context */
+       IF_FEATURE_GREP_CONTEXT(    OPTBIT_C ,) /* -C NUM: -A and -B combined */
+       IF_FEATURE_GREP_EGREP_ALIAS(OPTBIT_E ,) /* extended regexp */
+       IF_EXTRA_COMPAT(            OPTBIT_z ,) /* input is NUL terminated */
+       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_w = 1 << OPTBIT_w,
+       OPT_x = 1 << OPTBIT_x,
+       OPT_A = IF_FEATURE_GREP_CONTEXT(    (1 << OPTBIT_A)) + 0,
+       OPT_B = IF_FEATURE_GREP_CONTEXT(    (1 << OPTBIT_B)) + 0,
+       OPT_C = IF_FEATURE_GREP_CONTEXT(    (1 << OPTBIT_C)) + 0,
+       OPT_E = IF_FEATURE_GREP_EGREP_ALIAS((1 << OPTBIT_E)) + 0,
+       OPT_z = IF_EXTRA_COMPAT(            (1 << OPTBIT_z)) + 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)
+#define NUL_DELIMITED               (option_mask32 & OPT_z)
+
+struct globals {
+       int max_matches;
+#if !ENABLE_EXTRA_COMPAT
+       int reflags;
 #else
-#define GREP_OPT_CONTEXT ""
-#define GREP_OPT_A (0)
-#define GREP_OPT_B (0)
-#define GREP_OPT_C (0)
-#define GREP_OPT_E (1<<13)
+       RE_TRANSLATE_TYPE case_fold; /* RE_TRANSLATE_TYPE is [[un]signed] char* */
 #endif
-#if ENABLE_FEATURE_GREP_EGREP_ALIAS
-# define OPT_EGREP "E"
+       smalluint invert_search;
+       smalluint print_filename;
+       smalluint open_errors;
+#if ENABLE_FEATURE_GREP_CONTEXT
+       smalluint did_print_line;
+       int lines_before;
+       int lines_after;
+       char **before_buf;
+       IF_EXTRA_COMPAT(size_t *before_buf_size;)
+       int last_line_printed;
+#endif
+       /* globals used internally */
+       llist_t *pattern_head;   /* growable list of patterns to match */
+       const char *cur_file;    /* the current file we are reading */
+} FIX_ALIASING;
+#define G (*(struct globals*)&bb_common_bufsiz1)
+#define INIT_G() do { \
+       struct G_sizecheck { \
+               char G_sizecheck[sizeof(G) > COMMON_BUFSIZE ? -1 : 1]; \
+       }; \
+} while (0)
+#define max_matches       (G.max_matches         )
+#if !ENABLE_EXTRA_COMPAT
+# define reflags          (G.reflags             )
 #else
-# define OPT_EGREP ""
+# define case_fold        (G.case_fold           )
+/* http://www.delorie.com/gnu/docs/regex/regex_46.html */
+# define reflags           re_syntax_options
+# undef REG_NOSUB
+# undef REG_EXTENDED
+# undef REG_ICASE
+# define REG_NOSUB    bug:is:here /* should not be used */
+/* Just RE_SYNTAX_EGREP is not enough, need to enable {n[,[m]]} too */
+# define REG_EXTENDED (RE_SYNTAX_EGREP | RE_INTERVALS | RE_NO_BK_BRACES)
+# define REG_ICASE    bug:is:here /* should not be used */
 #endif
-
-static int reflags;
-static int print_filename;
-
-#if ENABLE_FEATURE_GREP_CONTEXT
-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 char *cur_file;          /* the current file we are reading */
-
-typedef struct GREP_LIST_DATA {
+#define invert_search     (G.invert_search       )
+#define print_filename    (G.print_filename      )
+#define open_errors       (G.open_errors         )
+#define did_print_line    (G.did_print_line      )
+#define lines_before      (G.lines_before        )
+#define lines_after       (G.lines_after         )
+#define before_buf        (G.before_buf          )
+#define before_buf_size   (G.before_buf_size     )
+#define last_line_printed (G.last_line_printed   )
+#define pattern_head      (G.pattern_head        )
+#define cur_file          (G.cur_file            )
+
+
+typedef struct grep_list_data_t {
        char *pattern;
-       regex_t preg;
-#define PATTERN_MEM_A 1
+/* for GNU regex, matched_range must be persistent across grep_file() calls */
+#if !ENABLE_EXTRA_COMPAT
+       regex_t compiled_regex;
+       regmatch_t matched_range;
+#else
+       struct re_pattern_buffer compiled_regex;
+       struct re_registers matched_range;
+#endif
+#define ALLOCATED 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_EXTRA_COMPAT
+#define print_line(line, line_len, linenum, decoration) \
+       print_line(line, linenum, decoration)
+#endif
+static void print_line(const char *line, size_t line_len, 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) && last_line_printed &&
-                       last_line_printed < linenum - 1) {
+       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 > 0)
+       if (print_filename)
                printf("%s%c", cur_file, decoration);
        if (PRINT_LINE_NUM)
                printf("%i%c", linenum, decoration);
-       puts(line);
+       /* Emulate weird GNU grep behavior with -ov */
+       if ((option_mask32 & (OPT_v|OPT_o)) != (OPT_v|OPT_o)) {
+#if !ENABLE_EXTRA_COMPAT
+               puts(line);
+#else
+               fwrite(line, 1, line_len, stdout);
+               putchar(NUL_DELIMITED ? '\0' : '\n');
+#endif
+       }
 }
 
+#if ENABLE_EXTRA_COMPAT
+/* Unlike getline, this one removes trailing '\n' */
+static ssize_t FAST_FUNC bb_getline(char **line_ptr, size_t *line_alloc_len, FILE *file)
+{
+       ssize_t res_sz;
+       char *line;
+       int delim = (NUL_DELIMITED ? '\0' : '\n');
+
+       res_sz = getdelim(line_ptr, line_alloc_len, delim, file);
+       line = *line_ptr;
+
+       if (res_sz > 0) {
+               if (line[res_sz - 1] == delim)
+                       line[--res_sz] = '\0';
+       } else {
+               free(line); /* uclibc allocates a buffer even on EOF. WTF? */
+       }
+       return res_sz;
+}
+#endif
 
 static int grep_file(FILE *file)
 {
-       char *line;
-       invert_search_t ret;
+       smalluint found;
        int linenum = 0;
        int nmatches = 0;
+#if !ENABLE_EXTRA_COMPAT
+       char *line;
+#else
+       char *line = NULL;
+       ssize_t line_len;
+       size_t line_alloc_len;
+# define rm_so start[0]
+# define rm_eo end[0]
+#endif
 #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 */
-#endif /* ENABLE_FEATURE_GREP_CONTEXT */
+#else
+       enum { print_n_lines_after = 0 };
+#endif
 
-       while ((line = bb_get_chomped_line_from_file(file)) != NULL) {
+       while (
+#if !ENABLE_EXTRA_COMPAT
+               (line = xmalloc_fgetline(file)) != NULL
+#else
+               (line_len = bb_getline(&line, &line_alloc_len, file)) >= 0
+#endif
+       ) {
                llist_t *pattern_ptr = pattern_head;
-               grep_list_data_t * gl;
+               grep_list_data_t *gl = gl; /* for gcc */
 
                linenum++;
-               ret = 0;
+               found = 0;
                while (pattern_ptr) {
                        gl = (grep_list_data_t *)pattern_ptr->data;
                        if (FGREP_FLAG) {
-                               ret = strstr(line, gl->pattern) != NULL;
+                               char *match;
+                               char *str = line;
+ opt_f_again:
+                               match = ((option_mask32 & OPT_i)
+                                       ? strcasestr(str, gl->pattern)
+                                       : strstr(str, gl->pattern)
+                                       );
+                               if (match) {
+                                       if (option_mask32 & OPT_x) {
+                                               if (match != str)
+                                                       goto opt_f_not_found;
+                                               if (str[strlen(gl->pattern)] != '\0')
+                                                       goto opt_f_not_found;
+                                       } else
+                                       if (option_mask32 & OPT_w) {
+                                               char c = (match != str) ? match[-1] : ' ';
+                                               if (!isalnum(c) && c != '_') {
+                                                       c = match[strlen(gl->pattern)];
+                                                       if (!c || (!isalnum(c) && c != '_'))
+                                                               goto opt_f_found;
+                                               }
+                                               str = match + 1;
+                                               goto opt_f_again;
+                                       }
+ opt_f_found:
+                                       found = 1;
+ opt_f_not_found: ;
+                               }
                        } 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)) {
+#if ENABLE_EXTRA_COMPAT
+                               unsigned start_pos;
+#endif
+                               char *match_at;
+
+                               if (!(gl->flg_mem_alocated_compiled & COMPILED)) {
                                        gl->flg_mem_alocated_compiled |= COMPILED;
-                                       xregcomp(&(gl->preg), gl->pattern, reflags);
+#if !ENABLE_EXTRA_COMPAT
+                                       xregcomp(&gl->compiled_regex, gl->pattern, reflags);
+#else
+                                       memset(&gl->compiled_regex, 0, sizeof(gl->compiled_regex));
+                                       gl->compiled_regex.translate = case_fold; /* for -i */
+                                       if (re_compile_pattern(gl->pattern, strlen(gl->pattern), &gl->compiled_regex))
+                                               bb_error_msg_and_die("bad regex '%s'", gl->pattern);
+#endif
+                               }
+#if !ENABLE_EXTRA_COMPAT
+                               gl->matched_range.rm_so = 0;
+                               gl->matched_range.rm_eo = 0;
+#else
+                               start_pos = 0;
+#endif
+                               match_at = line;
+ opt_w_again:
+//bb_error_msg("'%s' start_pos:%d line_len:%d", match_at, start_pos, line_len);
+                               if (
+#if !ENABLE_EXTRA_COMPAT
+                                       regexec(&gl->compiled_regex, match_at, 1, &gl->matched_range, 0) == 0
+#else
+                                       re_search(&gl->compiled_regex, match_at, line_len,
+                                                       start_pos, /*range:*/ line_len,
+                                                       &gl->matched_range) >= 0
+#endif
+                               ) {
+                                       if (option_mask32 & OPT_x) {
+                                               found = (gl->matched_range.rm_so == 0
+                                                        && match_at[gl->matched_range.rm_eo] == '\0');
+                                       } else
+                                       if (!(option_mask32 & OPT_w)) {
+                                               found = 1;
+                                       } else {
+                                               char c = ' ';
+                                               if (gl->matched_range.rm_so)
+                                                       c = match_at[gl->matched_range.rm_so - 1];
+                                               if (!isalnum(c) && c != '_') {
+                                                       c = match_at[gl->matched_range.rm_eo];
+                                                       if (!c || (!isalnum(c) && c != '_')) {
+                                                               found = 1;
+                                                       } else {
+                       /*
+                        * Why check gl->matched_range.rm_eo?
+                        * Zero-length match makes -w skip the line:
+                        * "echo foo | grep ^" prints "foo",
+                        * "echo foo | grep -w ^" prints nothing.
+                        * Without such check, we can loop forever.
+                        */
+#if !ENABLE_EXTRA_COMPAT
+                                                               if (gl->matched_range.rm_eo != 0) {
+                                                                       match_at += gl->matched_range.rm_eo;
+                                                                       goto opt_w_again;
+                                                               }
+#else
+                                                               if (gl->matched_range.rm_eo > start_pos) {
+                                                                       start_pos = gl->matched_range.rm_eo;
+                                                                       goto opt_w_again;
+                                                               }
+#endif
+                                                       }
+                                               }
+                                       }
                                }
-                               ret |= regexec(&(gl->preg), line, 0, NULL, 0) == 0;
                        }
+                       /* If it's non-inverted search, we can stop
+                        * at first match */
+                       if (found && !invert_search)
+                               goto do_found;
                        pattern_ptr = pattern_ptr->link;
                } /* while (pattern_ptr) */
 
-               if ((ret ^ invert_search)) {
-
-                       if (PRINT_FILES_WITH_MATCHES || BE_QUIET)
-                               free(line);
-
-                       /* if we found a match but were told to be quiet, stop here */
-                       if (BE_QUIET || PRINT_FILES_WITHOUT_MATCHES)
-                               return -1;
-
-                               /* keep track of matches */
-                               nmatches++;
-
+               if (found ^ invert_search) {
+ do_found:
+                       /* 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(EXIT_SUCCESS);
+                               }
                                /* if we're just printing filenames, we stop after the first match */
-                               if (PRINT_FILES_WITH_MATCHES)
-                                       break;
+                               if (PRINT_FILES_WITH_MATCHES) {
+                                       puts(cur_file);
+                                       /* fall through to "return 1" */
+                               }
+                               /* OPT_L aka PRINT_FILES_WITHOUT_MATCHES: return early */
+                               return 1; /* one match */
+                       }
 
-                               /* 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++;
-                                               }
+                       /* Were we printing context and saw next (unwanted) match? */
+                       if ((option_mask32 & OPT_m) && nmatches > max_matches)
+                               break;
+#endif
 
-                                               /* 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++;
-                                               }
+                       /* 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], before_buf_size[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;
+                               /* make a note that we need to print 'after' lines */
+                               print_n_lines_after = lines_after;
+#endif
+                               if (option_mask32 & OPT_o) {
+                                       if (FGREP_FLAG) {
+                                               /* -Fo just prints the pattern
+                                                * (unless -v: -Fov doesnt print anything at all) */
+                                               if (found)
+                                                       print_line(gl->pattern, strlen(gl->pattern), linenum, ':');
+                                       } else while (1) {
+                                               unsigned start = gl->matched_range.rm_so;
+                                               unsigned end = gl->matched_range.rm_eo;
+                                               unsigned len = end - start;
+                                               char old = line[end];
+                                               line[end] = '\0';
+                                               /* Empty match is not printed: try "echo test | grep -o ''" */
+                                               if (len != 0)
+                                                       print_line(line + start, len, linenum, ':');
+                                               if (old == '\0')
+                                                       break;
+                                               line[end] = old;
+                                               if (len == 0)
+                                                       end++;
+#if !ENABLE_EXTRA_COMPAT
+                                               if (regexec(&gl->compiled_regex, line + end,
+                                                               1, &gl->matched_range, REG_NOTBOL) != 0)
+                                                       break;
+                                               gl->matched_range.rm_so += end;
+                                               gl->matched_range.rm_eo += end;
+#else
+                                               if (re_search(&gl->compiled_regex, line, line_len,
+                                                               end, line_len - end,
+                                                               &gl->matched_range) < 0)
+                                                       break;
 #endif
-                                       print_line(line, linenum, ':');
+                                       }
+                               } else {
+                                       print_line(line, line_len, linenum, ':');
                                }
                        }
+               }
 #if ENABLE_FEATURE_GREP_CONTEXT
-                       else { /* no match */
-                               /* Add the line to the circular 'before' buffer */
-                               if(lines_before) {
-                                       free(before_buf[curpos]);
-                                       before_buf[curpos] = bb_xstrdup(line);
-                                       curpos = (curpos + 1) % lines_before;
-                               }
-                       }
-
+               else { /* no match */
                        /* if we need to print some context lines after the last match, do so */
-                       if (print_n_lines_after && (last_line_printed != linenum)) {
-                               print_line(line, linenum, '-');
+                       if (print_n_lines_after) {
+                               print_line(line, strlen(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;
+                               IF_EXTRA_COMPAT(before_buf_size[curpos] = line_len;)
+                               curpos = (curpos + 1) % lines_before;
+                               /* avoid free(line) - we took the line */
+                               line = NULL;
                        }
+               }
+
 #endif /* ENABLE_FEATURE_GREP_CONTEXT */
+#if !ENABLE_EXTRA_COMPAT
                free(line);
-       }
-
+#endif
+               /* Did we print all context after last requested match? */
+               if ((option_mask32 & OPT_m)
+                && !print_n_lines_after
+                && nmatches == max_matches
+               ) {
+                       break;
+               }
+       } /* while (read line) */
 
        /* 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 > 0)
+               if (print_filename)
                        printf("%s:", cur_file);
-                   printf("%d\n", nmatches);
+               printf("%d\n", nmatches);
        }
 
-       /* grep -l: print just the filename, but only if we grepped the line in the file  */
-       if (PRINT_FILES_WITH_MATCHES && nmatches > 0) {
-               puts(cur_file);
-       }
-
-       /* grep -L: print just the filename, but only if we didn't grep the line in the file  */
-       if (PRINT_FILES_WITHOUT_MATCHES && nmatches == 0) {
+       /* 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);
        }
 
@@ -243,196 +605,238 @@ static int grep_file(FILE *file)
 
 #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)
+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)
+static char *add_grep_list_data(char *pattern)
 #endif
 {
-       grep_list_data_t *gl = xmalloc(sizeof(grep_list_data_t));
+       grep_list_data_t *gl = xzalloc(sizeof(*gl));
        gl->pattern = pattern;
 #if ENABLE_FEATURE_CLEAN_UP
        gl->flg_mem_alocated_compiled = flg_used_mem;
 #else
-       gl->flg_mem_alocated_compiled = 0;
+       /*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) {
+       while (fopt) {
+               char *line;
+               FILE *fp;
                llist_t *cur = fopt;
                char *ffile = cur->data;
 
                fopt = cur->link;
                free(cur);
-               f = bb_xfopen(ffile, "r");
-               while ((line = bb_get_chomped_line_from_file(f)) != NULL) {
-                       pattern_head = llist_add_to(pattern_head,
-                               new_grep_list_data(line, PATTERN_MEM_A));
+               fp = xfopen_stdin(ffile);
+               while ((line = xmalloc_fgetline(fp)) != NULL) {
+                       llist_add_to(&pattern_head,
+                               new_grep_list_data(line, ALLOCATED));
                }
+               fclose_if_not_stdin(fp);
        }
 }
 
+static int FAST_FUNC file_action_grep(const char *filename,
+                       struct stat *statbuf UNUSED_PARAM,
+                       void* matched,
+                       int depth UNUSED_PARAM)
+{
+       FILE *file = fopen_for_read(filename);
+       if (file == NULL) {
+               if (!SUPPRESS_ERR_MSGS)
+                       bb_simple_perror_msg(filename);
+               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;
+}
 
-extern int grep_main(int argc, char **argv)
+int grep_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int grep_main(int argc UNUSED_PARAM, char **argv)
 {
        FILE *file;
        int matched;
        llist_t *fopt = NULL;
-       int error_open_count = 0;
 
        /* do normal option parsing */
 #if ENABLE_FEATURE_GREP_CONTEXT
-  {
-       char *junk;
-       char *slines_after;
-       char *slines_before;
-       char *Copt;
-
-       bb_opt_complementally = "H-h:e::f::C-AB";
-       opt = bb_getopt_ulflags(argc, argv,
-               GREP_OPTS GREP_OPT_CONTEXT OPT_EGREP,
-               &pattern_head, &fopt,
-               &slines_after, &slines_before, &Copt);
-
-       if(opt & GREP_OPT_C) {
-               /* C option unseted A and B options, but next -A or -B
-                  may be ovewrite own option */
-               if(!(opt & GREP_OPT_A))         /* not overwtited */
-                       slines_after = Copt;
-               if(!(opt & GREP_OPT_B))         /* not overwtited */
-                       slines_before = Copt;
-               opt |= GREP_OPT_A|GREP_OPT_B;   /* set for parse now */
+       int Copt, opts;
+
+       /* -H unsets -h; -C unsets -A,-B; -e,-f are lists;
+        * -m,-A,-B,-C have numeric param */
+       opt_complementary = "H-h:C-AB:e::f::m+:A+:B+:C+";
+       opts = getopt32(argv,
+               OPTSTR_GREP,
+               &pattern_head, &fopt, &max_matches,
+               &lines_after, &lines_before, &Copt);
+
+       if (opts & OPT_C) {
+               /* -C unsets prev -A and -B, but following -A or -B
+                * may override it */
+               if (!(opts & OPT_A)) /* not overridden */
+                       lines_after = Copt;
+               if (!(opts & OPT_B)) /* not overridden */
+                       lines_before = Copt;
        }
-       if(opt & GREP_OPT_A) {
-               lines_after = strtoul(slines_after, &junk, 10);
-               if(*junk != '\0')
-                       bb_error_msg_and_die("invalid context length argument");
-       }
-       if(opt & GREP_OPT_B) {
-               lines_before = strtoul(slines_before, &junk, 10);
-               if(*junk != '\0')
-                       bb_error_msg_and_die("invalid context length argument");
-       }
-       /* sanity checks after parse may be invalid numbers ;-) */
-       if ((opt & (GREP_OPT_c|GREP_OPT_q|GREP_OPT_l|GREP_OPT_L))) {
-               opt &= ~GREP_OPT_n;
+       /* sanity checks */
+       if (opts & (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 = (char **)xcalloc(lines_before, sizeof(char *));
-  }
+       } else if (lines_before > 0) {
+               if (lines_before > INT_MAX / sizeof(long long))
+                       lines_before = INT_MAX / sizeof(long long);
+               /* overflow in (lines_before * sizeof(x)) is prevented (above) */
+               before_buf = xzalloc(lines_before * sizeof(before_buf[0]));
+               IF_EXTRA_COMPAT(before_buf_size = xzalloc(lines_before * sizeof(before_buf_size[0]));)
+       }
 #else
        /* with auto sanity checks */
-       bb_opt_complementally = "H-h:e::f::c-n:q-n:l-n";
-       opt = bb_getopt_ulflags(argc, argv, GREP_OPTS OPT_EGREP,
-               &pattern_head, &fopt);
+       /* -H unsets -h; -c,-q or -l unset -n; -e,-f are lists; -m N */
+       opt_complementary = "H-h:c-n:q-n:l-n:e::f::m+";
+       getopt32(argv, OPTSTR_GREP,
+               &pattern_head, &fopt, &max_matches);
 #endif
-       invert_search = (opt & GREP_OPT_v) != 0;        /* 0 | 1 */
-
-       if(opt & GREP_OPT_H)
-               print_filename++;
-       if(opt & GREP_OPT_h)
-               print_filename--;
-       if (pattern_head != NULL) {
-               /* convert char *argv[] to grep_list_data_t */
-               llist_t *cur;
+       invert_search = ((option_mask32 & OPT_v) != 0); /* 0 | 1 */
 
-               for(cur = pattern_head; cur; cur = cur->link)
+       {       /* 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(opt & GREP_OPT_f)
+       if (option_mask32 & OPT_f) {
                load_regexes_from_file(fopt);
+               if (!pattern_head) { /* -f EMPTY_FILE? */
+                       /* GNU grep treats it as "nothing matches" */
+                       llist_add_to(&pattern_head, new_grep_list_data((char*) "", 0));
+                       invert_search ^= 1;
+               }
+       }
 
-       if(ENABLE_FEATURE_GREP_FGREP_ALIAS && bb_applet_name[0] == 'f')
-               opt |= GREP_OPT_F;
+       if (ENABLE_FEATURE_GREP_FGREP_ALIAS && applet_name[0] == 'f')
+               option_mask32 |= OPT_F;
 
-       if(ENABLE_FEATURE_GREP_EGREP_ALIAS &&
-                       (bb_applet_name[0] == 'e' || (opt & GREP_OPT_E)))
-               reflags = REG_EXTENDED | REG_NOSUB;
-       else
+#if !ENABLE_EXTRA_COMPAT
+       if (!(option_mask32 & (OPT_o | OPT_w | OPT_x)))
                reflags = REG_NOSUB;
+#endif
 
-       if(opt & GREP_OPT_i)
+       if (ENABLE_FEATURE_GREP_EGREP_ALIAS
+        && (applet_name[0] == 'e' || (option_mask32 & OPT_E))
+       ) {
+               reflags |= REG_EXTENDED;
+       }
+#if ENABLE_EXTRA_COMPAT
+       else {
+               reflags = RE_SYNTAX_GREP;
+       }
+#endif
+
+       if (option_mask32 & OPT_i) {
+#if !ENABLE_EXTRA_COMPAT
                reflags |= REG_ICASE;
+#else
+               int i;
+               case_fold = xmalloc(256);
+               for (i = 0; i < 256; i++)
+                       case_fold[i] = (unsigned char)i;
+               for (i = 'a'; i <= 'z'; i++)
+                       case_fold[i] = (unsigned char)(i - ('a' - 'A'));
+#endif
+       }
 
        argv += optind;
-       argc -= optind;
 
-       /* if we didn't get a pattern from -e and no command file was specified,
-        * argv[optind] should be the pattern. no pattern, no worky */
+       /* if we didn't get a pattern from -e and no command file was specified,
+        * first parameter should be the pattern. no pattern, no worky */
        if (pattern_head == NULL) {
+               char *pattern;
                if (*argv == NULL)
                        bb_show_usage();
-               else {
-                       char *pattern = new_grep_list_data(*argv++, 0);
-
-                       pattern_head = llist_add_to(pattern_head, pattern);
-                       argc--;
-               }
+               pattern = new_grep_list_data(*argv++, 0);
+               llist_add_to(&pattern_head, pattern);
        }
 
-       /* 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++;
+       /* argv[0..(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 (argv[0] && argv[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. */
-       } else if (argc == 0) {
-               argc++;
-       }
        matched = 0;
-       while (argc--) {
-               cur_file = *argv++;
-               if(!cur_file || (*cur_file == '-' && !cur_file[1])) {
+       do {
+               cur_file = *argv;
+               file = stdin;
+               if (!cur_file || LONE_DASH(cur_file)) {
                        cur_file = "(standard input)";
-                       file = stdin;
                } else {
-                       file = fopen(cur_file, "r");
-               }
-               if (file == NULL) {
-                       if (!SUPPRESS_ERR_MSGS)
-                               bb_perror_msg("%s", cur_file);
-                       error_open_count++;
-               } else {
-                       matched += grep_file(file);
-                       if(matched < 0) {
-                               /* we found a match but were told to be quiet, stop here and
-                               * return success */
-                               break;
+                       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_for_read(cur_file);
+                       if (file == NULL) {
+                               if (!SUPPRESS_ERR_MSGS)
+                                       bb_simple_perror_msg(cur_file);
+                               open_errors = 1;
+                               continue;
                        }
-                       fclose(file);
                }
-       }
+               matched += grep_file(file);
+               fclose_if_not_stdin(file);
+ grep_done: ;
+       } while (*argv && *++argv);
 
        /* 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;
+                       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))
+                       if (gl->flg_mem_alocated_compiled & ALLOCATED)
                                free(gl->pattern);
-                       if((gl->flg_mem_alocated_compiled & COMPILED))
-                               regfree(&(gl->preg));
+                       if (gl->flg_mem_alocated_compiled & COMPILED)
+                               regfree(&gl->compiled_regex);
+                       free(gl);
                        free(pattern_head_ptr);
                }
        }
        /* 0 = success, 1 = failed, 2 = error */
-       /* If the -q option is specified, the exit status shall be zero
-        * if an input line is selected, even if an error was detected.  */
-       if(BE_QUIET && matched)
-               return 0;
-       if(error_open_count)
+       if (open_errors)
                return 2;
-       return !matched; /* invert return value 0 = success, 1 = failed */
+       return !matched; /* invert return value: 0 = success, 1 = failed */
 }