unexpand: correct behavior for --first-only --tabs=4
[oweals/busybox.git] / editors / sed.c
index 302a156051a23938e5c1425ee0bdc2c22cd964bc..d3444003e58d657d39ef2e6a3afd62dc075f0269 100644 (file)
  *
  * MAINTAINER: Rob Landley <rob@landley.net>
  *
- * Licensed under GPL version 2, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2, see file LICENSE in this source tree.
  */
-
 /* Code overview.
+ *
+ * Files are laid out to avoid unnecessary function declarations.  So for
+ * example, every function add_cmd calls occurs before add_cmd in this file.
+ *
+ * add_cmd() is called on each line of sed command text (from a file or from
+ * the command line).  It calls get_address() and parse_cmd_args().  The
+ * resulting sed_cmd_t structures are appended to a linked list
+ * (G.sed_cmd_head/G.sed_cmd_tail).
+ *
+ * process_files() does actual sedding, reading data lines from each input FILE*
+ * (which could be stdin) and applying the sed command list (sed_cmd_head) to
+ * each of the resulting lines.
+ *
+ * sed_main() is where external code calls into this, with a command line.
+ */
+/* Supported features and commands in this version of sed:
+ *
+ * - comments ('#')
+ * - address matching: num|/matchstr/[,num|/matchstr/|$]command
+ * - commands: (p)rint, (d)elete, (s)ubstitue (with g & I flags)
+ * - edit commands: (a)ppend, (i)nsert, (c)hange
+ * - file commands: (r)ead
+ * - backreferences in substitution expressions (\0, \1, \2...\9)
+ * - grouped commands: {cmd1;cmd2}
+ * - transliteration (y/source-chars/dest-chars/)
+ * - pattern space hold space storing / swapping (g, h, x)
+ * - labels / branching (: label, b, t, T)
+ *
+ * (Note: Specifying an address (range) to match is *optional*; commands
+ * default to the whole pattern space if no specific address match was
+ * requested.)
+ *
+ * Todo:
+ * - Create a wrapper around regex to make libc's regex conform with sed
+ *
+ * Reference
+ * http://www.opengroup.org/onlinepubs/007904975/utilities/sed.html
+ * http://pubs.opengroup.org/onlinepubs/9699919799/utilities/sed.html
+ * http://sed.sourceforge.net/sedfaq3.html
+ */
+//config:config SED
+//config:      bool "sed (12 kb)"
+//config:      default y
+//config:      help
+//config:      sed is used to perform text transformations on a file
+//config:      or input from a pipeline.
+
+//applet:IF_SED(APPLET(sed, BB_DIR_BIN, BB_SUID_DROP))
+
+//kbuild:lib-$(CONFIG_SED) += sed.o
+
+//usage:#define sed_trivial_usage
+//usage:       "[-i[SFX]] [-nrE] [-f FILE]... [-e CMD]... [FILE]...\n"
+//usage:       "or: sed [-i[SFX]] [-nrE] CMD [FILE]..."
+//usage:#define sed_full_usage "\n\n"
+//usage:       "       -e CMD  Add CMD to sed commands to be executed"
+//usage:     "\n       -f FILE Add FILE contents to sed commands to be executed"
+//usage:     "\n       -i[SFX] Edit files in-place (otherwise sends to stdout)"
+//usage:     "\n               Optionally back files up, appending SFX"
+//usage:     "\n       -n      Suppress automatic printing of pattern space"
+//usage:     "\n       -r,-E   Use extended regex syntax"
+//usage:     "\n"
+//usage:     "\nIf no -e or -f, the first non-option argument is the sed command string."
+//usage:     "\nRemaining arguments are input files (stdin if none)."
+//usage:
+//usage:#define sed_example_usage
+//usage:       "$ echo \"foo\" | sed -e 's/f[a-zA-Z]o/bar/g'\n"
+//usage:       "bar\n"
 
-  Files are laid out to avoid unnecessary function declarations.  So for
-  example, every function add_cmd calls occurs before add_cmd in this file.
-
-  add_cmd() is called on each line of sed command text (from a file or from
-  the command line).  It calls get_address() and parse_cmd_args().  The
-  resulting sed_cmd_t structures are appended to a linked list
-  (G.sed_cmd_head/G.sed_cmd_tail).
-
-  add_input_file() adds a FILE* to the list of input files.  We need to
-  know all input sources ahead of time to find the last line for the $ match.
-
-  process_files() does actual sedding, reading data lines from each input FILE *
-  (which could be stdin) and applying the sed command list (sed_cmd_head) to
-  each of the resulting lines.
-
-  sed_main() is where external code calls into this, with a command line.
-*/
-
-
-/*
-       Supported features and commands in this version of sed:
-
-        - comments ('#')
-        - address matching: num|/matchstr/[,num|/matchstr/|$]command
-        - commands: (p)rint, (d)elete, (s)ubstitue (with g & I flags)
-        - edit commands: (a)ppend, (i)nsert, (c)hange
-        - file commands: (r)ead
-        - backreferences in substitution expressions (\0, \1, \2...\9)
-        - grouped commands: {cmd1;cmd2}
-        - transliteration (y/source-chars/dest-chars/)
-        - pattern space hold space storing / swapping (g, h, x)
-        - labels / branching (: label, b, t, T)
-
-        (Note: Specifying an address (range) to match is *optional*; commands
-        default to the whole pattern space if no specific address match was
-        requested.)
+#include "libbb.h"
+#include "common_bufsiz.h"
+#include "xregex.h"
 
-       Todo:
-        - Create a wrapper around regex to make libc's regex conform with sed
+#if 0
+# define dbg(...) bb_error_msg(__VA_ARGS__)
+#else
+# define dbg(...) ((void)0)
+#endif
 
-       Reference http://www.opengroup.org/onlinepubs/007904975/utilities/sed.html
-*/
 
-#include "libbb.h"
-#include "xregex.h"
+enum {
+       OPT_in_place = 1 << 0,
+};
 
 /* Each sed command turns into one of these structures. */
 typedef struct sed_cmd_s {
@@ -71,9 +107,11 @@ typedef struct sed_cmd_s {
        regex_t *end_match;     /* sed -e '/match/,/end_match/cmd' */
        regex_t *sub_match;     /* For 's/sub_match/string/' */
        int beg_line;           /* 'sed 1p'   0 == apply commands to all lines */
-       int end_line;           /* 'sed 1,3p' 0 == one line only. -1 = last line ($) */
+       int beg_line_orig;      /* copy of the above, needed for -i */
+       int end_line;           /* 'sed 1,3p' 0 == one line only. -1 = last line ($). -2-N = +N */
+       int end_line_orig;
 
-       FILE *sw_file;          /* File (sw) command writes to, -1 for none. */
+       FILE *sw_file;          /* File (sw) command writes to, NULL for none. */
        char *string;           /* Data string for (saicytb) commands. */
 
        unsigned which_match;   /* (s) Which match to replace (0 for all) */
@@ -94,35 +132,37 @@ static const char semicolon_whitespace[] ALIGN1 = "; \n\r\t\v";
 struct globals {
        /* options */
        int be_quiet, regex_type;
+
        FILE *nonstdout;
        char *outname, *hold_space;
+       smallint exitcode;
 
-       /* List of input files */
-       int input_file_count, current_input_file;
-       FILE **input_file_list;
+       /* list of input files */
+       int current_input_file, last_input_file;
+       char **input_file_list;
+       FILE *current_fp;
 
        regmatch_t regmatch[10];
        regex_t *previous_regex_ptr;
 
        /* linked list of sed commands */
-       sed_cmd_t sed_cmd_head, *sed_cmd_tail;
+       sed_cmd_t *sed_cmd_head, **sed_cmd_tail;
 
-       /* Linked list of append lines */
+       /* linked list of append lines */
        llist_t *append_head;
 
        char *add_cmd_line;
 
        struct pipeline {
-               char *buf;      /* Space to hold string */
-               int idx;        /* Space used */
-               int len;        /* Space allocated */
+               char *buf;  /* Space to hold string */
+               int idx;    /* Space used */
+               int len;    /* Space allocated */
        } pipeline;
 } FIX_ALIASING;
-#define G (*(struct globals*)&bb_common_bufsiz1)
-void BUG_sed_globals_too_big(void);
+#define G (*(struct globals*)bb_common_bufsiz1)
 #define INIT_G() do { \
-       if (sizeof(struct globals) > COMMON_BUFSIZE) \
-               BUG_sed_globals_too_big(); \
+       setup_common_bufsiz(); \
+       BUILD_BUG_ON(sizeof(G) > COMMON_BUFSIZE); \
        G.sed_cmd_tail = &G.sed_cmd_head; \
 } while (0)
 
@@ -130,7 +170,7 @@ void BUG_sed_globals_too_big(void);
 #if ENABLE_FEATURE_CLEAN_UP
 static void sed_free_and_close_stuff(void)
 {
-       sed_cmd_t *sed_cmd = G.sed_cmd_head.next;
+       sed_cmd_t *sed_cmd = G.sed_cmd_head;
 
        llist_free(G.append_head, free);
 
@@ -138,20 +178,25 @@ static void sed_free_and_close_stuff(void)
                sed_cmd_t *sed_cmd_next = sed_cmd->next;
 
                if (sed_cmd->sw_file)
-                       xprint_and_close_file(sed_cmd->sw_file);
+                       fclose(sed_cmd->sw_file);
 
-               if (sed_cmd->beg_match) {
-                       regfree(sed_cmd->beg_match);
-                       free(sed_cmd->beg_match);
-               }
-               if (sed_cmd->end_match) {
-                       regfree(sed_cmd->end_match);
-                       free(sed_cmd->end_match);
-               }
-               if (sed_cmd->sub_match) {
-                       regfree(sed_cmd->sub_match);
-                       free(sed_cmd->sub_match);
-               }
+               /* Used to free regexps, but now there is code
+                * in get_address() which can reuse a regexp
+                * for constructs as /regexp/cmd1;//cmd2
+                * leading to double-frees here:
+                */
+               //if (sed_cmd->beg_match) {
+               //      regfree(sed_cmd->beg_match);
+               //      free(sed_cmd->beg_match);
+               //}
+               //if (sed_cmd->end_match) {
+               //      regfree(sed_cmd->end_match);
+               //      free(sed_cmd->end_match);
+               //}
+               //if (sed_cmd->sub_match) {
+               //      regfree(sed_cmd->sub_match);
+               //      free(sed_cmd->sub_match);
+               //}
                free(sed_cmd->string);
                free(sed_cmd);
                sed_cmd = sed_cmd_next;
@@ -159,8 +204,8 @@ static void sed_free_and_close_stuff(void)
 
        free(G.hold_space);
 
-       while (G.current_input_file < G.input_file_count)
-               fclose(G.input_file_list[G.current_input_file++]);
+       if (G.current_fp)
+               fclose(G.current_fp);
 }
 #else
 void sed_free_and_close_stuff(void);
@@ -175,32 +220,46 @@ static void cleanup_outname(void)
 
 /* strcpy, replacing "\from" with 'to'. If to is NUL, replacing "\any" with 'any' */
 
-static void parse_escapes(char *dest, const char *string, int len, char from, char to)
+static unsigned parse_escapes(char *dest, const char *string, int len, char from, char to)
 {
+       char *d = dest;
        int i = 0;
 
+       if (len == -1)
+               len = strlen(string);
+
        while (i < len) {
                if (string[i] == '\\') {
                        if (!to || string[i+1] == from) {
-                               *dest++ = to ? to : string[i+1];
+                               if ((*d = to ? to : string[i+1]) == '\0')
+                                       return d - dest;
                                i += 2;
+                               d++;
                                continue;
                        }
-                       *dest++ = string[i++];
+                       i++; /* skip backslash in string[] */
+                       *d++ = '\\';
+                       /* fall through: copy next char verbatim */
                }
-               /* TODO: is it safe wrt a string with trailing '\\' ? */
-               *dest++ = string[i++];
+               if ((*d = string[i++]) == '\0')
+                       return d - dest;
+               d++;
        }
-       *dest = '\0';
+       *d = '\0';
+       return d - dest;
 }
 
 static char *copy_parsing_escapes(const char *string, int len)
 {
+       const char *s;
        char *dest = xmalloc(len + 1);
 
-       parse_escapes(dest, string, len, 'n', '\n');
-       /* GNU sed also recognizes \t */
-       parse_escapes(dest, dest, strlen(dest), 't', '\t');
+       /* sed recognizes \n */
+       /* GNU sed also recognizes \t and \r */
+       for (s = "\nn\tt\rr"; *s; s += 2) {
+               len = parse_escapes(dest, string, len, s[1], s[0]);
+               string = dest;
+       }
        return dest;
 }
 
@@ -223,11 +282,13 @@ static int index_of_next_unescaped_regexp_delim(int delimiter, const char *str)
                delimiter = -delimiter;
        }
 
-       for (; (ch = str[idx]); idx++) {
+       for (; (ch = str[idx]) != '\0'; idx++) {
                if (bracket >= 0) {
-                       if (ch == ']' && !(bracket == idx - 1 || (bracket == idx - 2
-                                       && str[idx - 1] == '^')))
+                       if (ch == ']'
+                        && !(bracket == idx - 1 || (bracket == idx - 2 && str[idx - 1] == '^'))
+                       ) {
                                bracket = -1;
+                       }
                } else if (escaped)
                        escaped = 0;
                else if (ch == '\\')
@@ -248,13 +309,13 @@ static int index_of_next_unescaped_regexp_delim(int delimiter, const char *str)
 static int parse_regex_delim(const char *cmdstr, char **match, char **replace)
 {
        const char *cmdstr_ptr = cmdstr;
-       char delimiter;
+       unsigned char delimiter;
        int idx = 0;
 
        /* verify that the 's' or 'y' is followed by something.  That something
         * (typically a 'slash') is now our regexp delimiter... */
        if (*cmdstr == '\0')
-               bb_error_msg_and_die("bad format in substitution expression");
+               bb_simple_error_msg_and_die("bad format in substitution expression");
        delimiter = *cmdstr_ptr++;
 
        /* save the match string */
@@ -263,7 +324,7 @@ static int parse_regex_delim(const char *cmdstr, char **match, char **replace)
 
        /* save the replacement string */
        cmdstr_ptr += idx + 1;
-       idx = index_of_next_unescaped_regexp_delim(-delimiter, cmdstr_ptr);
+       idx = index_of_next_unescaped_regexp_delim(- (int)delimiter, cmdstr_ptr);
        *replace = copy_parsing_escapes(cmdstr_ptr, idx);
 
        return ((cmdstr_ptr - cmdstr) + idx);
@@ -278,7 +339,7 @@ static int get_address(const char *my_str, int *linenum, regex_t ** regex)
 
        if (isdigit(*my_str)) {
                *linenum = strtol(my_str, (char**)&pos, 10);
-               /* endstr shouldnt ever equal NULL */
+               /* endstr shouldn't ever equal NULL */
        } else if (*my_str == '$') {
                *linenum = -1;
                pos++;
@@ -288,12 +349,19 @@ static int get_address(const char *my_str, int *linenum, regex_t ** regex)
                char *temp;
 
                delimiter = '/';
-               if (*my_str == '\\') delimiter = *++pos;
+               if (*my_str == '\\')
+                       delimiter = *++pos;
                next = index_of_next_unescaped_regexp_delim(delimiter, ++pos);
-               temp = copy_parsing_escapes(pos, next);
-               *regex = xmalloc(sizeof(regex_t));
-               xregcomp(*regex, temp, G.regex_type|REG_NEWLINE);
-               free(temp);
+               if (next != 0) {
+                       temp = copy_parsing_escapes(pos, next);
+                       G.previous_regex_ptr = *regex = xzalloc(sizeof(regex_t));
+                       xregcomp(*regex, temp, G.regex_type);
+                       free(temp);
+               } else {
+                       *regex = G.previous_regex_ptr;
+                       if (!G.previous_regex_ptr)
+                               bb_simple_error_msg_and_die("no previous regexp");
+               }
                /* Move position to next character after last delimiter */
                pos += (next+1);
        }
@@ -303,25 +371,25 @@ static int get_address(const char *my_str, int *linenum, regex_t ** regex)
 /* Grab a filename.  Whitespace at start is skipped, then goes to EOL. */
 static int parse_file_cmd(/*sed_cmd_t *sed_cmd,*/ const char *filecmdstr, char **retval)
 {
-       int start = 0, idx, hack = 0;
+       const char *start;
+       const char *eol;
 
        /* Skip whitespace, then grab filename to end of line */
-       while (isspace(filecmdstr[start]))
-               start++;
-       idx = start;
-       while (filecmdstr[idx] && filecmdstr[idx] != '\n')
-               idx++;
-
-       /* If lines glued together, put backslash back. */
-       if (filecmdstr[idx] == '\n')
-               hack = 1;
-       if (idx == start)
-               bb_error_msg_and_die("empty filename");
-       *retval = xstrndup(filecmdstr+start, idx-start+hack+1);
-       if (hack)
-               (*retval)[idx] = '\\';
+       start = skip_whitespace(filecmdstr);
+       eol = strchrnul(start, '\n');
+       if (eol == start)
+               bb_simple_error_msg_and_die("empty filename");
+
+       if (*eol) {
+               /* If lines glued together, put backslash back. */
+               *retval = xstrndup(start, eol-start + 1);
+               (*retval)[eol-start] = '\\';
+       } else {
+               /* eol is NUL */
+               *retval = xstrdup(start);
+       }
 
-       return idx;
+       return eol - filecmdstr;
 }
 
 static int parse_subst_cmd(sed_cmd_t *sed_cmd, const char *substr)
@@ -332,7 +400,7 @@ static int parse_subst_cmd(sed_cmd_t *sed_cmd, const char *substr)
 
        /*
         * A substitution command should look something like this:
-        *    s/match/replace/ #gIpw
+        *    s/match/replace/ #giIpw
         *    ||     |        |||
         *    mandatory       optional
         */
@@ -346,7 +414,9 @@ static int parse_subst_cmd(sed_cmd_t *sed_cmd, const char *substr)
        /* process the flags */
 
        sed_cmd->which_match = 1;
+       dbg("s flags:'%s'", substr + idx + 1);
        while (substr[++idx]) {
+               dbg("s flag:'%c'", substr[idx]);
                /* Parse match number */
                if (isdigit(substr[idx])) {
                        if (match[0] != '^') {
@@ -354,7 +424,7 @@ static int parse_subst_cmd(sed_cmd_t *sed_cmd, const char *substr)
                                const char *pos = substr + idx;
 /* FIXME: error check? */
                                sed_cmd->which_match = (unsigned)strtol(substr+idx, (char**) &pos, 10);
-                               idx = pos - substr;
+                               idx = pos - substr - 1;
                        }
                        continue;
                }
@@ -375,32 +445,40 @@ static int parse_subst_cmd(sed_cmd_t *sed_cmd, const char *substr)
                /* Write to file */
                case 'w':
                {
-                       char *temp;
-                       idx += parse_file_cmd(/*sed_cmd,*/ substr+idx, &temp);
+                       char *fname;
+                       idx += parse_file_cmd(/*sed_cmd,*/ substr+idx+1, &fname);
+                       sed_cmd->sw_file = xfopen_for_write(fname);
+                       sed_cmd->sw_last_char = '\n';
+                       free(fname);
                        break;
                }
-               /* Ignore case (gnu exension) */
+               /* Ignore case (gnu extension) */
+               case 'i':
                case 'I':
                        cflags |= REG_ICASE;
                        break;
                /* Comment */
                case '#':
-                       while (substr[++idx]) /*skip all*/;
+                       // while (substr[++idx]) continue;
+                       idx += strlen(substr + idx); // same
                        /* Fall through */
                /* End of command */
                case ';':
                case '}':
                        goto out;
                default:
-                       bb_error_msg_and_die("bad option in substitution expression");
+                       dbg("s bad flags:'%s'", substr + idx);
+                       bb_simple_error_msg_and_die("bad option in substitution expression");
                }
        }
-out:
+ out:
        /* compile the match string into a regex */
        if (*match != '\0') {
                /* If match is empty, we use last regex used at runtime */
-               sed_cmd->sub_match = xmalloc(sizeof(regex_t));
+               sed_cmd->sub_match = xzalloc(sizeof(regex_t));
+               dbg("xregcomp('%s',%x)", match, cflags);
                xregcomp(sed_cmd->sub_match, match, cflags);
+               dbg("regcomp ok");
        }
        free(match);
 
@@ -412,13 +490,55 @@ out:
  */
 static const char *parse_cmd_args(sed_cmd_t *sed_cmd, const char *cmdstr)
 {
+       static const char cmd_letters[] ALIGN1 = "saicrw:btTydDgGhHlnNpPqx={}";
+       enum {
+               IDX_s = 0,
+               IDX_a,
+               IDX_i,
+               IDX_c,
+               IDX_r,
+               IDX_w,
+               IDX_colon,
+               IDX_b,
+               IDX_t,
+               IDX_T,
+               IDX_y,
+               IDX_d,
+               IDX_D,
+               IDX_g,
+               IDX_G,
+               IDX_h,
+               IDX_H,
+               IDX_l,
+               IDX_n,
+               IDX_N,
+               IDX_p,
+               IDX_P,
+               IDX_q,
+               IDX_x,
+               IDX_equal,
+               IDX_lbrace,
+               IDX_rbrace,
+               IDX_nul
+       };
+       unsigned idx;
+
+       BUILD_BUG_ON(sizeof(cmd_letters)-1 != IDX_nul);
+
+       idx = strchrnul(cmd_letters, sed_cmd->cmd) - cmd_letters;
+
        /* handle (s)ubstitution command */
-       if (sed_cmd->cmd == 's')
+       if (idx == IDX_s) {
                cmdstr += parse_subst_cmd(sed_cmd, cmdstr);
+       }
        /* handle edit cmds: (a)ppend, (i)nsert, and (c)hange */
-       else if (strchr("aic", sed_cmd->cmd)) {
-               if ((sed_cmd->end_line || sed_cmd->end_match) && sed_cmd->cmd != 'c')
-                       bb_error_msg_and_die("only a beginning address can be specified for edit commands");
+       else if (idx <= IDX_c) { /* a,i,c */
+               unsigned len;
+
+               if (idx < IDX_c) { /* a,i */
+                       if (sed_cmd->end_line || sed_cmd->end_match)
+                               bb_error_msg_and_die("command '%c' uses only one address", sed_cmd->cmd);
+               }
                for (;;) {
                        if (*cmdstr == '\n' || *cmdstr == '\\') {
                                cmdstr++;
@@ -428,21 +548,26 @@ static const char *parse_cmd_args(sed_cmd_t *sed_cmd, const char *cmdstr)
                                break;
                        cmdstr++;
                }
-               sed_cmd->string = xstrdup(cmdstr);
+               len = strlen(cmdstr);
+               sed_cmd->string = copy_parsing_escapes(cmdstr, len);
+               cmdstr += len;
                /* "\anychar" -> "anychar" */
-               parse_escapes(sed_cmd->string, sed_cmd->string, strlen(cmdstr), '\0', '\0');
-               cmdstr += strlen(cmdstr);
+               parse_escapes(sed_cmd->string, sed_cmd->string, -1, '\0', '\0');
+       }
        /* handle file cmds: (r)ead */
-       } else if (strchr("rw", sed_cmd->cmd)) {
-               if (sed_cmd->end_line || sed_cmd->end_match)
-                       bb_error_msg_and_die("command only uses one address");
+       else if (idx <= IDX_w) { /* r,w */
+               if (idx < IDX_w) { /* r */
+                       if (sed_cmd->end_line || sed_cmd->end_match)
+                               bb_error_msg_and_die("command '%c' uses only one address", sed_cmd->cmd);
+               }
                cmdstr += parse_file_cmd(/*sed_cmd,*/ cmdstr, &sed_cmd->string);
                if (sed_cmd->cmd == 'w') {
                        sed_cmd->sw_file = xfopen_for_write(sed_cmd->string);
                        sed_cmd->sw_last_char = '\n';
                }
+       }
        /* handle branch commands */
-       } else if (strchr(":btT", sed_cmd->cmd)) {
+       else if (idx <= IDX_T) { /* :,b,t,T */
                int length;
 
                cmdstr = skip_whitespace(cmdstr);
@@ -453,14 +578,14 @@ static const char *parse_cmd_args(sed_cmd_t *sed_cmd, const char *cmdstr)
                }
        }
        /* translation command */
-       else if (sed_cmd->cmd == 'y') {
+       else if (idx == IDX_y) {
                char *match, *replace;
                int i = cmdstr[0];
 
                cmdstr += parse_regex_delim(cmdstr, &match, &replace)+1;
                /* \n already parsed, but \delimiter needs unescaping. */
-               parse_escapes(match, match, strlen(match), i, i);
-               parse_escapes(replace, replace, strlen(replace), i, i);
+               parse_escapes(match,   match,   -1, i, i);
+               parse_escapes(replace, replace, -1, i, i);
 
                sed_cmd->string = xzalloc((strlen(match) + 1) * 2);
                for (i = 0; match[i] && replace[i]; i++) {
@@ -470,10 +595,10 @@ static const char *parse_cmd_args(sed_cmd_t *sed_cmd, const char *cmdstr)
                free(match);
                free(replace);
        }
-       /* if it wasnt a single-letter command that takes no arguments
+       /* if it wasn't a single-letter command that takes no arguments
         * then it must be an invalid command.
         */
-       else if (strchr("dDgGhHlnNpPqx={}", sed_cmd->cmd) == 0) {
+       else if (idx >= IDX_nul) { /* not d,D,g,G,h,H,l,n,N,p,P,q,x,=,{,} */
                bb_error_msg_and_die("unsupported command %c", sed_cmd->cmd);
        }
 
@@ -487,7 +612,7 @@ static const char *parse_cmd_args(sed_cmd_t *sed_cmd, const char *cmdstr)
 static void add_cmd(const char *cmdstr)
 {
        sed_cmd_t *sed_cmd;
-       int temp;
+       unsigned len, n;
 
        /* Append this line to any unfinished line from last time. */
        if (G.add_cmd_line) {
@@ -496,12 +621,14 @@ static void add_cmd(const char *cmdstr)
                cmdstr = G.add_cmd_line = tp;
        }
 
-       /* If this line ends with backslash, request next line. */
-       temp = strlen(cmdstr);
-       if (temp && cmdstr[--temp] == '\\') {
+       /* If this line ends with unescaped backslash, request next line. */
+       n = len = strlen(cmdstr);
+       while (n && cmdstr[n-1] == '\\')
+               n--;
+       if ((len - n) & 1) { /* if odd number of trailing backslashes */
                if (!G.add_cmd_line)
                        G.add_cmd_line = xstrdup(cmdstr);
-               G.add_cmd_line[temp] = '\0';
+               G.add_cmd_line[len-1] = '\0';
                return;
        }
 
@@ -533,16 +660,36 @@ static void add_cmd(const char *cmdstr)
 
                /* first part (if present) is an address: either a '$', a number or a /regex/ */
                cmdstr += get_address(cmdstr, &sed_cmd->beg_line, &sed_cmd->beg_match);
+               sed_cmd->beg_line_orig = sed_cmd->beg_line;
 
                /* second part (if present) will begin with a comma */
                if (*cmdstr == ',') {
                        int idx;
 
                        cmdstr++;
-                       idx = get_address(cmdstr, &sed_cmd->end_line, &sed_cmd->end_match);
-                       if (!idx)
-                               bb_error_msg_and_die("no address after comma");
-                       cmdstr += idx;
+                       if (*cmdstr == '+' && isdigit(cmdstr[1])) {
+                               /* http://sed.sourceforge.net/sedfaq3.html#s3.3
+                                * Under GNU sed 3.02+, ssed, and sed15+, <address2>
+                                * may also be a notation of the form +num,
+                                * indicating the next num lines after <address1> is
+                                * matched.
+                                * GNU sed 4.2.1 accepts even "+" (meaning "+0").
+                                * We don't (we check for isdigit, see above), think
+                                * about the "+-3" case.
+                                */
+                               char *end;
+                               /* code is smaller compared to using &cmdstr here: */
+                               idx = strtol(cmdstr+1, &end, 10);
+                               sed_cmd->end_line = -2 - idx;
+                               cmdstr = end;
+                       } else {
+                               idx = get_address(cmdstr, &sed_cmd->end_line, &sed_cmd->end_match);
+                               cmdstr += idx;
+                               idx--; /* if 0, trigger error check below */
+                       }
+                       if (idx < 0)
+                               bb_simple_error_msg_and_die("no address after comma");
+                       sed_cmd->end_line_orig = sed_cmd->end_line;
                }
 
                /* skip whitespace before the command */
@@ -559,13 +706,19 @@ static void add_cmd(const char *cmdstr)
 
                /* last part (mandatory) will be a command */
                if (!*cmdstr)
-                       bb_error_msg_and_die("missing command");
-               sed_cmd->cmd = *(cmdstr++);
+                       bb_simple_error_msg_and_die("missing command");
+               sed_cmd->cmd = *cmdstr++;
                cmdstr = parse_cmd_args(sed_cmd, cmdstr);
 
+               /* cmdstr now points past args.
+                * GNU sed requires a separator, if there are more commands,
+                * else it complains "char N: extra characters after command".
+                * Example: "sed 'p;d'". We also allow "sed 'pd'".
+                */
+
                /* Add the command to the command array */
-               G.sed_cmd_tail->next = sed_cmd;
-               G.sed_cmd_tail = G.sed_cmd_tail->next;
+               *G.sed_cmd_tail = sed_cmd;
+               G.sed_cmd_tail = &sed_cmd->next;
        }
 
        /* If we glued multiple lines together, free the memory. */
@@ -593,7 +746,7 @@ static void do_subst_w_backrefs(char *line, char *replace)
 
        /* go through the replacement string */
        for (i = 0; replace[i]; i++) {
-               /* if we find a backreference (\1, \2, etc.) print the backref'ed text */
+               /* if we find a backreference (\1, \2, etc.) print the backref'ed text */
                if (replace[i] == '\\') {
                        unsigned backref = replace[++i] - '0';
                        if (backref <= 9) {
@@ -606,7 +759,7 @@ static void do_subst_w_backrefs(char *line, char *replace)
                                continue;
                        }
                        /* I _think_ it is impossible to get '\' to be
-                        * the last char in replace string. Thus we dont check
+                        * the last char in replace string. Thus we don't check
                         * for replace[i] == NUL. (counterexample anyone?) */
                        /* if we find a backslash escaped character, print the character */
                        pipe_putc(replace[i]);
@@ -627,8 +780,10 @@ static void do_subst_w_backrefs(char *line, char *replace)
 static int do_subst_command(sed_cmd_t *sed_cmd, char **line_p)
 {
        char *line = *line_p;
-       int altered = 0;
        unsigned match_count = 0;
+       bool altered = 0;
+       bool prev_match_empty = 1;
+       bool tried_at_eol = 0;
        regex_t *current_regex;
 
        current_regex = sed_cmd->sub_match;
@@ -636,13 +791,17 @@ static int do_subst_command(sed_cmd_t *sed_cmd, char **line_p)
        if (!current_regex) {
                current_regex = G.previous_regex_ptr;
                if (!current_regex)
-                       bb_error_msg_and_die("no previous regexp");
+                       bb_simple_error_msg_and_die("no previous regexp");
        }
        G.previous_regex_ptr = current_regex;
 
        /* Find the first match */
-       if (REG_NOMATCH == regexec(current_regex, line, 10, G.regmatch, 0))
+       dbg("matching '%s'", line);
+       if (REG_NOMATCH == regexec(current_regex, line, 10, G.regmatch, 0)) {
+               dbg("no match");
                return 0;
+       }
+       dbg("match");
 
        /* Initialize temporary output buffer. */
        G.pipeline.buf = xmalloc(PIPE_GROW);
@@ -651,47 +810,76 @@ static int do_subst_command(sed_cmd_t *sed_cmd, char **line_p)
 
        /* Now loop through, substituting for matches */
        do {
+               int start = G.regmatch[0].rm_so;
+               int end = G.regmatch[0].rm_eo;
                int i;
 
-               /* Work around bug in glibc regexec, demonstrated by:
-                  echo " a.b" | busybox sed 's [^ .]* x g'
-                  The match_count check is so not to break
-                  echo "hi" | busybox sed 's/^/!/g' */
-               if (!G.regmatch[0].rm_so && !G.regmatch[0].rm_eo && match_count) {
-                       pipe_putc(*line++);
-                       continue;
-               }
-
                match_count++;
 
                /* If we aren't interested in this match, output old line to
-                  end of match and continue */
+                * end of match and continue */
                if (sed_cmd->which_match
                 && (sed_cmd->which_match != match_count)
                ) {
-                       for (i = 0; i < G.regmatch[0].rm_eo; i++)
+                       for (i = 0; i < end; i++)
                                pipe_putc(*line++);
-                       continue;
+                       /* Null match? Print one more char */
+                       if (start == end && *line)
+                               pipe_putc(*line++);
+                       goto next;
                }
 
-               /* print everything before the match */
-               for (i = 0; i < G.regmatch[0].rm_so; i++)
+               /* Print everything before the match */
+               for (i = 0; i < start; i++)
                        pipe_putc(line[i]);
 
-               /* then print the substitution string */
-               do_subst_w_backrefs(line, sed_cmd->string);
+               /* Then print the substitution string,
+                * unless we just matched empty string after non-empty one.
+                * Example: string "cccd", pattern "c*", repl "R":
+                * result is "RdR", not "RRdR": first match "ccc",
+                * second is "" before "d", third is "" after "d".
+                * Second match is NOT replaced!
+                */
+               if (prev_match_empty || start != 0 || start != end) {
+                       //dbg("%d %d %d", prev_match_empty, start, end);
+                       dbg("inserting replacement at %d in '%s'", start, line);
+                       do_subst_w_backrefs(line, sed_cmd->string);
+                       /* Flag that something has changed */
+                       altered = 1;
+               } else {
+                       dbg("NOT inserting replacement at %d in '%s'", start, line);
+               }
 
-               /* advance past the match */
-               line += G.regmatch[0].rm_eo;
-               /* flag that something has changed */
-               altered++;
+               /* If matched string is empty (f.e. "c*" pattern),
+                * copy verbatim one char after it before attempting more matches
+                */
+               prev_match_empty = (start == end);
+               if (prev_match_empty) {
+                       if (!line[end]) {
+                               tried_at_eol = 1;
+                       } else {
+                               pipe_putc(line[end]);
+                               end++;
+                       }
+               }
+
+               /* Advance past the match */
+               dbg("line += %d", end);
+               line += end;
 
                /* if we're not doing this globally, get out now */
-               if (sed_cmd->which_match)
+               if (sed_cmd->which_match != 0)
                        break;
+ next:
+               /* Exit if we are at EOL and already tried matching at it */
+               if (*line == '\0') {
+                       if (tried_at_eol)
+                               break;
+                       tried_at_eol = 1;
+               }
 
-//maybe (G.regmatch[0].rm_eo ? REG_NOTBOL : 0) instead of unconditional REG_NOTBOL?
-       } while (*line && regexec(current_regex, line, 10, G.regmatch, REG_NOTBOL) != REG_NOMATCH);
+//maybe (end ? REG_NOTBOL : 0) instead of unconditional REG_NOTBOL?
+       } while (regexec(current_regex, line, 10, G.regmatch, REG_NOTBOL) != REG_NOMATCH);
 
        /* Copy rest of string into output pipeline */
        while (1) {
@@ -711,8 +899,11 @@ static sed_cmd_t *branch_to(char *label)
 {
        sed_cmd_t *sed_cmd;
 
-       for (sed_cmd = G.sed_cmd_head.next; sed_cmd; sed_cmd = sed_cmd->next) {
-               if (sed_cmd->cmd == ':' && sed_cmd->string && !strcmp(sed_cmd->string, label)) {
+       for (sed_cmd = G.sed_cmd_head; sed_cmd; sed_cmd = sed_cmd->next) {
+               if (sed_cmd->cmd == ':'
+                && sed_cmd->string
+                && strcmp(sed_cmd->string, label) == 0
+               ) {
                        return sed_cmd;
                }
        }
@@ -721,46 +912,109 @@ static sed_cmd_t *branch_to(char *label)
 
 static void append(char *s)
 {
-       llist_add_to_end(&G.append_head, xstrdup(s));
+       llist_add_to_end(&G.append_head, s);
 }
 
-static void flush_append(void)
+/* Output line of text. */
+/* Note:
+ * The tricks with NO_EOL_CHAR and last_puts_char are there to emulate gnu sed.
+ * Without them, we had this:
+ * echo -n thingy >z1
+ * echo -n again >z2
+ * >znull
+ * sed "s/i/z/" z1 z2 znull | hexdump -vC
+ * output:
+ * gnu sed 4.1.5:
+ * 00000000  74 68 7a 6e 67 79 0a 61  67 61 7a 6e              |thzngy.agazn|
+ * bbox:
+ * 00000000  74 68 7a 6e 67 79 61 67  61 7a 6e                 |thzngyagazn|
+ */
+enum {
+       NO_EOL_CHAR = 1,
+       LAST_IS_NUL = 2,
+};
+static void puts_maybe_newline(char *s, FILE *file, char *last_puts_char, char last_gets_char)
 {
-       char *data;
+       char lpc = *last_puts_char;
 
-       /* Output appended lines. */
-       while ((data = (char *)llist_pop(&G.append_head))) {
-               fprintf(G.nonstdout, "%s\n", data);
-               free(data);
+       /* Need to insert a '\n' between two files because first file's
+        * last line wasn't terminated? */
+       if (lpc != '\n' && lpc != '\0') {
+               fputc('\n', file);
+               lpc = '\n';
        }
+       fputs(s, file);
+
+       /* 'x' - just something which is not '\n', '\0' or NO_EOL_CHAR */
+       if (s[0])
+               lpc = 'x';
+
+       /* had trailing '\0' and it was last char of file? */
+       if (last_gets_char == LAST_IS_NUL) {
+               fputc('\0', file);
+               lpc = 'x'; /* */
+       } else
+       /* had trailing '\n' or '\0'? */
+       if (last_gets_char != NO_EOL_CHAR) {
+               fputc(last_gets_char, file);
+               lpc = last_gets_char;
+       }
+
+       if (ferror(file)) {
+               xfunc_error_retval = 4;  /* It's what gnu sed exits with... */
+               bb_simple_error_msg_and_die(bb_msg_write_error);
+       }
+       *last_puts_char = lpc;
 }
 
-static void add_input_file(FILE *file)
+static void flush_append(char *last_puts_char)
 {
-       G.input_file_list = xrealloc_vector(G.input_file_list, 2, G.input_file_count);
-       G.input_file_list[G.input_file_count++] = file;
+       char *data;
+
+       /* Output appended lines. */
+       while ((data = (char *)llist_pop(&G.append_head)) != NULL) {
+               /* Append command does not respect "nonterminated-ness"
+                * of last line. Try this:
+                * $ echo -n "woot" | sed -e '/woot/a woo' -
+                * woot
+                * woo
+                * (both lines are terminated with \n)
+                * Therefore we do not propagate "last_gets_char" here,
+                * pass '\n' instead:
+                */
+               puts_maybe_newline(data, G.nonstdout, last_puts_char, '\n');
+               free(data);
+       }
 }
 
 /* Get next line of input from G.input_file_list, flushing append buffer and
  * noting if we ran out of files without a newline on the last line we read.
  */
-enum {
-       NO_EOL_CHAR = 1,
-       LAST_IS_NUL = 2,
-};
-static char *get_next_line(char *gets_char)
+static char *get_next_line(char *gets_char, char *last_puts_char)
 {
        char *temp = NULL;
-       int len;
+       size_t len;
        char gc;
 
-       flush_append();
+       flush_append(last_puts_char);
 
        /* will be returned if last line in the file
         * doesn't end with either '\n' or '\0' */
        gc = NO_EOL_CHAR;
-       while (G.current_input_file < G.input_file_count) {
-               FILE *fp = G.input_file_list[G.current_input_file];
+       for (; G.current_input_file <= G.last_input_file; G.current_input_file++) {
+               FILE *fp = G.current_fp;
+               if (!fp) {
+                       const char *path = G.input_file_list[G.current_input_file];
+                       fp = stdin;
+                       if (path != bb_msg_standard_input) {
+                               fp = fopen_or_warn(path, "r");
+                               if (!fp) {
+                                       G.exitcode = EXIT_FAILURE;
+                                       continue;
+                               }
+                       }
+                       G.current_fp = fp;
+               }
                /* Read line up to a newline or NUL byte, inclusive,
                 * return malloc'ed char[]. length of the chunk read
                 * is stored in len. NULL if EOF/error */
@@ -791,61 +1045,13 @@ static char *get_next_line(char *gets_char)
                 * (note: *no* newline after "b bang"!) */
                }
                /* Close this file and advance to next one */
-               fclose(fp);
-               G.current_input_file++;
+               fclose_if_not_stdin(fp);
+               G.current_fp = NULL;
        }
        *gets_char = gc;
        return temp;
 }
 
-/* Output line of text. */
-/* Note:
- * The tricks with NO_EOL_CHAR and last_puts_char are there to emulate gnu sed.
- * Without them, we had this:
- * echo -n thingy >z1
- * echo -n again >z2
- * >znull
- * sed "s/i/z/" z1 z2 znull | hexdump -vC
- * output:
- * gnu sed 4.1.5:
- * 00000000  74 68 7a 6e 67 79 0a 61  67 61 7a 6e              |thzngy.agazn|
- * bbox:
- * 00000000  74 68 7a 6e 67 79 61 67  61 7a 6e                 |thzngyagazn|
- */
-static void puts_maybe_newline(char *s, FILE *file, char *last_puts_char, char last_gets_char)
-{
-       char lpc = *last_puts_char;
-
-       /* Need to insert a '\n' between two files because first file's
-        * last line wasn't terminated? */
-       if (lpc != '\n' && lpc != '\0') {
-               fputc('\n', file);
-               lpc = '\n';
-       }
-       fputs(s, file);
-
-       /* 'x' - just something which is not '\n', '\0' or NO_EOL_CHAR */
-       if (s[0])
-               lpc = 'x';
-
-       /* had trailing '\0' and it was last char of file? */
-       if (last_gets_char == LAST_IS_NUL) {
-               fputc('\0', file);
-               lpc = 'x'; /* */
-       } else
-       /* had trailing '\n' or '\0'? */
-       if (last_gets_char != NO_EOL_CHAR) {
-               fputc(last_gets_char, file);
-               lpc = last_gets_char;
-       }
-
-       if (ferror(file)) {
-               xfunc_error_retval = 4;  /* It's what gnu sed exits with... */
-               bb_error_msg_and_die(bb_msg_write_error);
-       }
-       *last_puts_char = lpc;
-}
-
 #define sed_puts(s, n) (puts_maybe_newline(s, G.nonstdout, &last_puts_char, n))
 
 static int beg_match(sed_cmd_t *sed_cmd, const char *pattern_space)
@@ -868,7 +1074,7 @@ static void process_files(void)
        int substituted;
 
        /* Prime the pump */
-       next_line = get_next_line(&next_gets_char);
+       next_line = get_next_line(&next_gets_char, &last_puts_char);
 
        /* Go through every line in each file */
  again:
@@ -882,25 +1088,53 @@ static void process_files(void)
 
        /* Read one line in advance so we can act on the last line,
         * the '$' address */
-       next_line = get_next_line(&next_gets_char);
+       next_line = get_next_line(&next_gets_char, &last_puts_char);
        linenum++;
 
        /* For every line, go through all the commands */
  restart:
-       for (sed_cmd = G.sed_cmd_head.next; sed_cmd; sed_cmd = sed_cmd->next) {
+       for (sed_cmd = G.sed_cmd_head; sed_cmd; sed_cmd = sed_cmd->next) {
                int old_matched, matched;
 
                old_matched = sed_cmd->in_match;
+               if (!old_matched)
+                       sed_cmd->end_line = sed_cmd->end_line_orig;
 
                /* Determine if this command matches this line: */
 
+               dbg("match1:%d", sed_cmd->in_match);
+               dbg("match2:%d", (!sed_cmd->beg_line && !sed_cmd->end_line
+                               && !sed_cmd->beg_match && !sed_cmd->end_match));
+               dbg("match3:%d", (sed_cmd->beg_line > 0
+                       && (sed_cmd->end_line || sed_cmd->end_match
+                           ? (sed_cmd->beg_line <= linenum)
+                           : (sed_cmd->beg_line == linenum)
+                           )
+                       ));
+               dbg("match4:%d", (beg_match(sed_cmd, pattern_space)));
+               dbg("match5:%d", (sed_cmd->beg_line == -1 && next_line == NULL));
+
                /* Are we continuing a previous multi-line match? */
                sed_cmd->in_match = sed_cmd->in_match
                        /* Or is no range necessary? */
                        || (!sed_cmd->beg_line && !sed_cmd->end_line
                                && !sed_cmd->beg_match && !sed_cmd->end_match)
                        /* Or did we match the start of a numerical range? */
-                       || (sed_cmd->beg_line > 0 && (sed_cmd->beg_line <= linenum))
+                       || (sed_cmd->beg_line > 0
+                           && (sed_cmd->end_line || sed_cmd->end_match
+                                 /* note: even if end is numeric and is < linenum too,
+                                  * GNU sed matches! We match too, therefore we don't
+                                  * check here that linenum <= end.
+                                  * Example:
+                                  * printf '1\n2\n3\n4\n' | sed -n '1{N;N;d};1p;2,3p;3p;4p'
+                                  * first three input lines are deleted;
+                                  * 4th line is matched and printed
+                                  * by "2,3" (!) and by "4" ranges
+                                  */
+                               ? (sed_cmd->beg_line <= linenum)    /* N,end */
+                               : (sed_cmd->beg_line == linenum)    /* N */
+                               )
+                           )
                        /* Or does this line match our begin address regex? */
                        || (beg_match(sed_cmd, pattern_space))
                        /* Or did we match last line of input? */
@@ -909,37 +1143,56 @@ static void process_files(void)
                /* Snapshot the value */
                matched = sed_cmd->in_match;
 
-               //bb_error_msg("cmd:'%c' matched:%d beg_line:%d end_line:%d linenum:%d",
-               //sed_cmd->cmd, matched, sed_cmd->beg_line, sed_cmd->end_line, linenum);
+               dbg("cmd:'%c' matched:%d beg_line:%d end_line:%d linenum:%d",
+                       sed_cmd->cmd, matched, sed_cmd->beg_line, sed_cmd->end_line, linenum);
 
                /* Is this line the end of the current match? */
 
                if (matched) {
+                       if (sed_cmd->end_line <= -2) {
+                               /* address2 is +N, i.e. N lines from beg_line */
+                               sed_cmd->end_line = linenum + (-sed_cmd->end_line - 2);
+                       }
                        /* once matched, "n,xxx" range is dead, disabling it */
-                       if (sed_cmd->beg_line > 0)
+                       if (sed_cmd->beg_line > 0) {
                                sed_cmd->beg_line = -2;
+                       }
+                       dbg("end1:%d", sed_cmd->end_line ? sed_cmd->end_line == -1
+                                               ? !next_line : (sed_cmd->end_line <= linenum)
+                                       : !sed_cmd->end_match);
+                       dbg("end2:%d", sed_cmd->end_match && old_matched
+                                       && !regexec(sed_cmd->end_match,pattern_space, 0, NULL, 0));
                        sed_cmd->in_match = !(
                                /* has the ending line come, or is this a single address command? */
-                               (sed_cmd->end_line ?
-                                       sed_cmd->end_line == -1 ?
-                                               !next_line
+                               (sed_cmd->end_line
+                                       ? sed_cmd->end_line == -1
+                                               !next_line
                                                : (sed_cmd->end_line <= linenum)
                                        : !sed_cmd->end_match
                                )
                                /* or does this line matches our last address regex */
                                || (sed_cmd->end_match && old_matched
                                     && (regexec(sed_cmd->end_match,
-                                                pattern_space, 0, NULL, 0) == 0))
+                                               pattern_space, 0, NULL, 0) == 0)
+                               )
                        );
                }
 
                /* Skip blocks of commands we didn't match */
                if (sed_cmd->cmd == '{') {
                        if (sed_cmd->invert ? matched : !matched) {
-                               while (sed_cmd->cmd != '}') {
+                               unsigned nest_cnt = 0;
+                               while (1) {
+                                       if (sed_cmd->cmd == '{')
+                                               nest_cnt++;
+                                       if (sed_cmd->cmd == '}') {
+                                               nest_cnt--;
+                                               if (nest_cnt == 0)
+                                                       break;
+                                       }
                                        sed_cmd = sed_cmd->next;
                                        if (!sed_cmd)
-                                               bb_error_msg_and_die("unterminated {");
+                                               bb_simple_error_msg_and_die("unterminated {");
                                }
                        }
                        continue;
@@ -955,6 +1208,8 @@ static void process_files(void)
                }
 
                /* actual sedding */
+               dbg("pattern_space:'%s' next_line:'%s' cmd:%c",
+                               pattern_space, next_line, sed_cmd->cmd);
                switch (sed_cmd->cmd) {
 
                /* Print line number */
@@ -966,7 +1221,6 @@ static void process_files(void)
                case 'P':
                {
                        char *tmp = strchr(pattern_space, '\n');
-
                        if (tmp) {
                                *tmp = '\0';
                                /* TODO: explain why '\n' below */
@@ -989,11 +1243,8 @@ static void process_files(void)
                case 'D':
                {
                        char *tmp = strchr(pattern_space, '\n');
-
                        if (tmp) {
-                               tmp = xstrdup(tmp+1);
-                               free(pattern_space);
-                               pattern_space = tmp;
+                               overlapping_strcpy(pattern_space, tmp + 1);
                                goto restart;
                        }
                }
@@ -1005,6 +1256,7 @@ static void process_files(void)
                case 's':
                        if (!do_subst_command(sed_cmd, &pattern_space))
                                break;
+                       dbg("do_subst_command succeeded:'%s'", pattern_space);
                        substituted |= 1;
 
                        /* handle p option */
@@ -1019,7 +1271,7 @@ static void process_files(void)
 
                /* Append line to linked list to be printed later */
                case 'a':
-                       append(sed_cmd->string);
+                       append(xstrdup(sed_cmd->string));
                        break;
 
                /* Insert text before this line */
@@ -1038,15 +1290,13 @@ static void process_files(void)
                case 'r':
                {
                        FILE *rfile;
-
                        rfile = fopen_for_read(sed_cmd->string);
                        if (rfile) {
                                char *line;
-
                                while ((line = xmalloc_fgetline(rfile))
                                                != NULL)
                                        append(line);
-                               xprint_and_close_file(rfile);
+                               fclose(rfile);
                        }
 
                        break;
@@ -1063,16 +1313,17 @@ static void process_files(void)
                case 'n':
                        if (!G.be_quiet)
                                sed_puts(pattern_space, last_gets_char);
-                       if (next_line) {
-                               free(pattern_space);
-                               pattern_space = next_line;
-                               last_gets_char = next_gets_char;
-                               next_line = get_next_line(&next_gets_char);
-                               substituted = 0;
-                               linenum++;
-                               break;
+                       if (next_line == NULL) {
+                               /* If no next line, jump to end of script and exit. */
+                               goto discard_line;
                        }
-                       /* fall through */
+                       free(pattern_space);
+                       pattern_space = next_line;
+                       last_gets_char = next_gets_char;
+                       next_line = get_next_line(&next_gets_char, &last_puts_char);
+                       substituted = 0;
+                       linenum++;
+                       break;
 
                /* Quit.  End of script, end of input. */
                case 'q':
@@ -1086,19 +1337,24 @@ static void process_files(void)
                {
                        int len;
                        /* If no next line, jump to end of script and exit. */
+                       /* http://www.gnu.org/software/sed/manual/sed.html:
+                        * "Most versions of sed exit without printing anything
+                        * when the N command is issued on the last line of
+                        * a file. GNU sed prints pattern space before exiting
+                        * unless of course the -n command switch has been
+                        * specified. This choice is by design."
+                        */
                        if (next_line == NULL) {
-                               /* Jump to end of script and exit */
-                               free(next_line);
-                               next_line = NULL;
-                               goto discard_line;
-                       /* append next_line, read new next_line. */
+                               //goto discard_line;
+                               goto discard_commands; /* GNU behavior */
                        }
+                       /* Append next_line, read new next_line. */
                        len = strlen(pattern_space);
                        pattern_space = xrealloc(pattern_space, len + strlen(next_line) + 2);
                        pattern_space[len] = '\n';
                        strcpy(pattern_space + len+1, next_line);
                        last_gets_char = next_gets_char;
-                       next_line = get_next_line(&next_gets_char);
+                       next_line = get_next_line(&next_gets_char, &last_puts_char);
                        linenum++;
                        break;
                }
@@ -1121,7 +1377,6 @@ static void process_files(void)
                case 'y':
                {
                        int i, j;
-
                        for (i = 0; pattern_space[i]; i++) {
                                for (j = 0; sed_cmd->string[j]; j += 2) {
                                        if (pattern_space[i] == sed_cmd->string[j]) {
@@ -1203,7 +1458,7 @@ static void process_files(void)
 
        /* Delete and such jump here. */
  discard_line:
-       flush_append();
+       flush_append(&last_puts_char /*,last_gets_char*/);
        free(pattern_space);
 
        goto again;
@@ -1212,7 +1467,7 @@ static void process_files(void)
 /* It is possible to have a command line argument with embedded
  * newlines.  This counts as multiple command lines.
  * However, newline can be escaped: 's/e/z\<newline>z/'
- * We check for this.
+ * add_cmd() handles this.
  */
 
 static void add_cmd_block(char *cmdstr)
@@ -1222,22 +1477,8 @@ static void add_cmd_block(char *cmdstr)
        cmdstr = sv = xstrdup(cmdstr);
        do {
                eol = strchr(cmdstr, '\n');
- next:
-               if (eol) {
-                       /* Count preceding slashes */
-                       int slashes = 0;
-                       char *sl = eol;
-
-                       while (sl != cmdstr && *--sl == '\\')
-                               slashes++;
-                       /* Odd number of preceding slashes - newline is escaped */
-                       if (slashes & 1) {
-                               overlapping_strcpy(eol - 1, eol);
-                               eol = strchr(eol, '\n');
-                               goto next;
-                       }
+               if (eol)
                        *eol = '\0';
-               }
                add_cmd(cmdstr);
                cmdstr = eol + 1;
        } while (eol);
@@ -1247,12 +1488,20 @@ static void add_cmd_block(char *cmdstr)
 int sed_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int sed_main(int argc UNUSED_PARAM, char **argv)
 {
-       enum {
-               OPT_in_place = 1 << 0,
-       };
        unsigned opt;
        llist_t *opt_e, *opt_f;
-       int status = EXIT_SUCCESS;
+       char *opt_i;
+
+#if ENABLE_LONG_OPTS
+       static const char sed_longopts[] ALIGN1 =
+               /* name             has_arg             short */
+               "in-place\0"        Optional_argument   "i"
+               "regexp-extended\0" No_argument         "r"
+               "quiet\0"           No_argument         "n"
+               "silent\0"          No_argument         "n"
+               "expression\0"      Required_argument   "e"
+               "file\0"            Required_argument   "f";
+#endif
 
        INIT_G();
 
@@ -1260,39 +1509,49 @@ int sed_main(int argc UNUSED_PARAM, char **argv)
        if (ENABLE_FEATURE_CLEAN_UP) atexit(sed_free_and_close_stuff);
 
        /* Lie to autoconf when it starts asking stupid questions. */
-       if (argv[1] && !strcmp(argv[1], "--version")) {
+       if (argv[1] && strcmp(argv[1], "--version") == 0) {
                puts("This is not GNU sed version 4.0");
                return 0;
        }
 
        /* do normal option parsing */
        opt_e = opt_f = NULL;
-       opt_complementary = "e::f::" /* can occur multiple times */
-                           "nn"; /* count -n */
-       opt = getopt32(argv, "irne:f:", &opt_e, &opt_f,
-                           &G.be_quiet); /* counter for -n */
+       opt_i = NULL;
+       /* -i must be first, to match OPT_in_place definition */
+       /* -E is a synonym of -r:
+        * GNU sed 4.2.1 mentions it in neither --help
+        * nor manpage, but does recognize it.
+        */
+       opt = getopt32long(argv, "^"
+                       "i::rEne:*f:*"
+                       "\0" "nn"/*count -n*/,
+                       sed_longopts,
+                       &opt_i, &opt_e, &opt_f,
+                       &G.be_quiet); /* counter for -n */
        //argc -= optind;
        argv += optind;
        if (opt & OPT_in_place) { // -i
-               atexit(cleanup_outname);
+               die_func = cleanup_outname;
        }
-       if (opt & 0x2) G.regex_type |= REG_EXTENDED; // -r
-       //if (opt & 0x4) G.be_quiet++; // -n
+       if (opt & (2|4))
+               G.regex_type |= REG_EXTENDED; // -r or -E
+       //if (opt & 8)
+       //      G.be_quiet++; // -n (implemented with a counter instead)
        while (opt_e) { // -e
                add_cmd_block(llist_pop(&opt_e));
        }
        while (opt_f) { // -f
                char *line;
                FILE *cmdfile;
-               cmdfile = xfopen_for_read(llist_pop(&opt_f));
+               cmdfile = xfopen_stdin(llist_pop(&opt_f));
                while ((line = xmalloc_fgetline(cmdfile)) != NULL) {
                        add_cmd(line);
                        free(line);
                }
-               fclose(cmdfile);
+               fclose_if_not_stdin(cmdfile);
        }
        /* if we didn't get a pattern from -e or -f, use argv[0] */
-       if (!(opt & 0x18)) {
+       if (!(opt & 0x30)) {
                if (!*argv)
                        bb_show_usage();
                add_cmd_block(*argv++);
@@ -1306,57 +1565,75 @@ int sed_main(int argc UNUSED_PARAM, char **argv)
        /* argv[0..(argc-1)] should be names of file to process. If no
         * files were specified or '-' was specified, take input from stdin.
         * Otherwise, we process all the files specified. */
-       if (argv[0] == NULL) {
+       G.input_file_list = argv;
+       if (!argv[0]) {
                if (opt & OPT_in_place)
                        bb_error_msg_and_die(bb_msg_requires_arg, "-i");
-               add_input_file(stdin);
-               process_files();
+               argv[0] = (char*)bb_msg_standard_input;
+               /* G.last_input_file = 0; - already is */
        } else {
-               int i;
-               FILE *file;
+               goto start;
 
-               for (i = 0; argv[i]; i++) {
+               for (; *argv; argv++) {
                        struct stat statbuf;
                        int nonstdoutfd;
+                       sed_cmd_t *sed_cmd;
 
-                       if (LONE_DASH(argv[i]) && !(opt & OPT_in_place)) {
-                               add_input_file(stdin);
-                               process_files();
-                               continue;
-                       }
-                       file = fopen_or_warn(argv[i], "r");
-                       if (!file) {
-                               status = EXIT_FAILURE;
-                               continue;
-                       }
+                       G.last_input_file++;
+ start:
                        if (!(opt & OPT_in_place)) {
-                               add_input_file(file);
+                               if (LONE_DASH(*argv)) {
+                                       *argv = (char*)bb_msg_standard_input;
+                                       process_files();
+                               }
                                continue;
                        }
 
-                       G.outname = xasprintf("%sXXXXXX", argv[i]);
-                       nonstdoutfd = mkstemp(G.outname);
-                       if (-1 == nonstdoutfd)
-                               bb_perror_msg_and_die("can't create temp file %s", G.outname);
-                       G.nonstdout = xfdopen_for_write(nonstdoutfd);
+                       /* -i: process each FILE separately: */
 
+                       if (stat(*argv, &statbuf) != 0) {
+                               bb_simple_perror_msg(*argv);
+                               G.exitcode = EXIT_FAILURE;
+                               G.current_input_file++;
+                               continue;
+                       }
+                       G.outname = xasprintf("%sXXXXXX", *argv);
+                       nonstdoutfd = xmkstemp(G.outname);
+                       G.nonstdout = xfdopen_for_write(nonstdoutfd);
                        /* Set permissions/owner of output file */
-                       fstat(fileno(file), &statbuf);
+                       /* chmod'ing AFTER chown would preserve suid/sgid bits,
+                        * but GNU sed 4.2.1 does not preserve them either */
                        fchmod(nonstdoutfd, statbuf.st_mode);
                        fchown(nonstdoutfd, statbuf.st_uid, statbuf.st_gid);
-                       add_input_file(file);
+
                        process_files();
                        fclose(G.nonstdout);
-
                        G.nonstdout = stdout;
-                       /* unlink(argv[i]); */
-                       xrename(G.outname, argv[i]);
+
+                       if (opt_i) {
+                               char *backupname = xasprintf("%s%s", *argv, opt_i);
+                               xrename(*argv, backupname);
+                               free(backupname);
+                       }
+                       /* else unlink(*argv); - rename below does this */
+                       xrename(G.outname, *argv); //TODO: rollback backup on error?
                        free(G.outname);
                        G.outname = NULL;
+
+                       /* Fix disabled range matches and mangled ",+N" ranges */
+                       for (sed_cmd = G.sed_cmd_head; sed_cmd; sed_cmd = sed_cmd->next) {
+                               sed_cmd->beg_line = sed_cmd->beg_line_orig;
+                               sed_cmd->end_line = sed_cmd->end_line_orig;
+                       }
                }
-               if (G.input_file_count > G.current_input_file)
-                       process_files();
+               /* Here, to handle "sed 'cmds' nonexistent_file" case we did:
+                * if (G.current_input_file[G.current_input_file] == NULL)
+                *      return G.exitcode;
+                * but it's not needed since process_files() works correctly
+                * in this case too. */
        }
 
-       return status;
+       process_files();
+
+       return G.exitcode;
 }