sed: improve handling of NULs

2 files changed, 69 insertions, 51 deletions

diff --git a/editors/sed.c b/editors/sed.c
index a16023945..630d6d792 100644
--- a/editors/sed.c
+++ b/editors/sed.c
@@ -80,8 +80,8 @@ typedef struct sed_cmd_s {
         /* Bitfields (gcc won't group them if we don't) */
         unsigned int invert:1;          /* the '!' after the address */
         unsigned int in_match:1;        /* Next line also included in match? */
-        unsigned int no_newline:1;      /* Last line written by (sw) had no '\n' */
         unsigned int sub_p:1;           /* (s) print option */
+        int last_char;                  /* Last line written by (sw) had no '\n' */
 
         /* GENERAL FIELDS */
         char cmd;               /* The command char: abcdDgGhHilnNpPqrstwxy:={} */
@@ -712,56 +712,73 @@ static void add_input_file(FILE *file)
 /* Get next line of input from bbg.input_file_list, flushing append buffer and
  * noting if we ran out of files without a newline on the last line we read.
  */
-static char *get_next_line(int *no_newline)
+static char *get_next_line(int *last_char)
 {
         char *temp = NULL;
         int len;
 
+        /* will be returned if last line in the file
+         * doesn't end with either '\n' or '\0' */
+        *last_char = 0x100;
+
         flush_append();
         while (bbg.current_input_file < bbg.input_file_count) {
-                temp = bb_get_chunk_from_file(bbg.input_file_list[bbg.current_input_file],&len);
+                temp = bb_get_chunk_from_file(
+                        bbg.input_file_list[bbg.current_input_file], &len);
                 if (temp) {
-                        *no_newline = !(len && temp[len-1] == '\n');
-                        if (!*no_newline) temp[len-1] = 0;
+                        /* len > 0 here, it's ok to do temp[len-1] */
+                        char c = temp[len-1];
+                        if (c == '\n' || c == '\0') {
+                                temp[len-1] = '\0';
+                                *last_char = (unsigned char)c;
+                        }
                         break;
-                // Close this file and advance to next one
-                } else
-                        fclose(bbg.input_file_list[bbg.current_input_file++]);
+                }
+                /* Close this file and advance to next one */
+                fclose(bbg.input_file_list[bbg.current_input_file++]);
         }
-
         return temp;
 }
 
-/* Output line of text.  missing_newline means the last line output did not
-   end with a newline.  no_newline means this line does not end with a
-   newline. */
+/* Output line of text. */
+/* Note:
+ * 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|
+ * I am not sure that bbox is wrong here...
+ */
 
-static int puts_maybe_newline(char *s, FILE *file, int missing_newline, int no_newline)
+static int puts_maybe_newline(char *s, FILE *file, int prev_last_char, int last_char)
 {
-        if (missing_newline) fputc('\n',file);
-        fputs(s,file);
-        if (!no_newline) fputc('\n',file);
+        fputs(s, file);
+        if (last_char < 0x100) fputc(last_char, file);
 
         if (ferror(file)) {
                 xfunc_error_retval = 4;  /* It's what gnu sed exits with... */
                 bb_error_msg_and_die(bb_msg_write_error);
         }
 
-        return no_newline;
+        return last_char;
 }
 
-#define sed_puts(s,n) missing_newline=puts_maybe_newline(s,bbg.nonstdout,missing_newline,n)
+#define sed_puts(s, n) \
+        (prev_last_char = puts_maybe_newline(s, bbg.nonstdout, prev_last_char, n))
 
 /* Process all the lines in all the files */
 
 static void process_files(void)
 {
         char *pattern_space, *next_line;
-        int linenum = 0, missing_newline = 0;
-        int no_newline,next_no_newline = 0;
+        int linenum = 0, prev_last_char = 0;
+        int last_char, next_last_char = 0;
 
         /* Prime the pump */
-        next_line = get_next_line(&next_no_newline);
+        next_line = get_next_line(&next_last_char);
 
         /* go through every line in each file */
         for (;;) {
@@ -771,11 +788,11 @@ static void process_files(void)
                 /* Advance to next line.  Stop if out of lines. */
                 pattern_space = next_line;
                 if (!pattern_space) break;
-                no_newline = next_no_newline;
+                last_char = next_last_char;
 
                 /* Read one line in advance so we can act on the last line,
                  * the '$' address */
-                next_line = get_next_line(&next_no_newline);
+                next_line = get_next_line(&next_last_char);
                 linenum++;
 restart:
                 /* for every line, go through all the commands */
@@ -858,7 +875,7 @@ restart:
 
                                 /* Write the current pattern space to output */
                                 case 'p':
-                                        sed_puts(pattern_space,no_newline);
+                                        sed_puts(pattern_space, last_char);
                                         break;
                                 /* Delete up through first newline */
                                 case 'D':
@@ -878,25 +895,24 @@ restart:
 
                                 /* Substitute with regex */
                                 case 's':
-                                        if (do_subst_command(sed_cmd, &pattern_space)) {
-                                                substituted |= 1;
-
-                                                /* handle p option */
-                                                if (sed_cmd->sub_p)
-                                                        sed_puts(pattern_space,no_newline);
-                                                /* handle w option */
-                                                if (sed_cmd->file)
-                                                        sed_cmd->no_newline = puts_maybe_newline(pattern_space, sed_cmd->file, sed_cmd->no_newline, no_newline);
-
-                                        }
+                                        if (!do_subst_command(sed_cmd, &pattern_space))
+                                                break;
+                                        substituted |= 1;
+
+                                        /* handle p option */
+                                        if (sed_cmd->sub_p)
+                                                sed_puts(pattern_space, last_char);
+                                        /* handle w option */
+                                        if (sed_cmd->file)
+                                                sed_cmd->last_char = puts_maybe_newline(
+                                                        pattern_space, sed_cmd->file,
+                                                        sed_cmd->last_char, last_char);
                                         break;
 
                                 /* Append line to linked list to be printed later */
                                 case 'a':
-                                {
                                         append(sed_cmd->string);
                                         break;
-                                }
 
                                 /* Insert text before this line */
                                 case 'i':
@@ -930,18 +946,20 @@ restart:
 
                                 /* Write pattern space to file. */
                                 case 'w':
-                                        sed_cmd->no_newline = puts_maybe_newline(pattern_space,sed_cmd->file, sed_cmd->no_newline,no_newline);
+                                        sed_cmd->last_char = puts_maybe_newline(
+                                                pattern_space,sed_cmd->file,
+                                                sed_cmd->last_char, last_char);
                                         break;
 
                                 /* Read next line from input */
                                 case 'n':
                                         if (!bbg.be_quiet)
-                                                sed_puts(pattern_space,no_newline);
+                                                sed_puts(pattern_space, last_char);
                                         if (next_line) {
                                                 free(pattern_space);
                                                 pattern_space = next_line;
-                                                no_newline = next_no_newline;
-                                                next_line = get_next_line(&next_no_newline);
+                                                last_char = next_last_char;
+                                                next_line = get_next_line(&next_last_char);
                                                 linenum++;
                                                 break;
                                         }
@@ -970,8 +988,8 @@ restart:
                                                 pattern_space = realloc(pattern_space, len + strlen(next_line) + 2);
                                                 pattern_space[len] = '\n';
                                                 strcpy(pattern_space + len+1, next_line);
-                                                no_newline = next_no_newline;
-                                                next_line = get_next_line(&next_no_newline);
+                                                last_char = next_last_char;
+                                                next_line = get_next_line(&next_last_char);
                                                 linenum++;
                                         }
                                         break;
@@ -1029,7 +1047,7 @@ restart:
                                         strcat(pattern_space, "\n");
                                         if (bbg.hold_space)
                                                 strcat(pattern_space, bbg.hold_space);
-                                        no_newline = 0;
+                                        last_char = 0x100;
 
                                         break;
                                 }
@@ -1061,7 +1079,7 @@ restart:
                                 {
                                         char *tmp = pattern_space;
                                         pattern_space = bbg.hold_space ? : xzalloc(1);
-                                        no_newline = 0;
+                                        last_char = 0x100;
                                         bbg.hold_space = tmp;
                                         break;
                                 }
@@ -1075,7 +1093,7 @@ restart:
 discard_commands:
                 /* we will print the line unless we were told to be quiet ('-n')
                    or if the line was suppressed (ala 'd'elete) */
-                if (!bbg.be_quiet) sed_puts(pattern_space,no_newline);
+                if (!bbg.be_quiet) sed_puts(pattern_space, last_char);
 
                 /* Delete and such jump here. */
 discard_line:
diff --git a/libbb/get_line_from_file.c b/libbb/get_line_from_file.c
index b424d59e9..3f2c6096e 100644
--- a/libbb/get_line_from_file.c
+++ b/libbb/get_line_from_file.c
@@ -11,8 +11,8 @@
 
 #include "libbb.h"
 
-/* This function reads an entire line from a text file,
- * up to a newline or NUL byte.  It returns a malloc'ed char * which must be
+/* This function reads an entire line from a text file, up to a newline 
+ * or NUL byte, inclusive.  It returns a malloc'ed char * which must be
  * stored and free'ed  by the caller.  If end is null '\n' isn't considered
  * end of line.  If end isn't null, length of the chunk read is stored in it. */
 
@@ -25,7 +25,7 @@ char *bb_get_chunk_from_file(FILE * file, int *end)
 
         while ((ch = getc(file)) != EOF) {
                 /* grow the line buffer as necessary */
-                if (idx > linebufsz - 2) {
+                if (idx >= linebufsz) {
                         linebuf = xrealloc(linebuf, linebufsz += 80);
                 }
                 linebuf[idx++] = (char) ch;
@@ -35,14 +35,14 @@ char *bb_get_chunk_from_file(FILE * file, int *end)
         if (end)
                 *end = idx;
         if (linebuf) {
-                // huh, is fgets discards prior data on error like this?
+                // huh, does fgets discard prior data on error like this?
                 // I don't think so....
                 //if (ferror(file)) {
                 //      free(linebuf);
                 //      return NULL;
                 //}
                 linebuf = xrealloc(linebuf, idx+1);
-                linebuf[idx] = 0;
+                linebuf[idx] = '\0';
         }
         return linebuf;
 }