hexdump: fix numerous bugs in handling of backslashes

Was:
	t=48\\	t=45\\	t=4c\\	t=4c\\	t=4f\\	t=0a\\
Now:
	=48=\n	=45=\n	=4c=\n	=4c=\n	=4f=\n	=0a=\n

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 31 insertions, 20 deletions

diff --git a/libbb/dump.c b/libbb/dump.c
index 566881a78..154be5d80 100644
--- a/libbb/dump.c
+++ b/libbb/dump.c
@@ -157,7 +157,7 @@ static NOINLINE void rewrite(priv_dumper_t *dumper, FS *fs)
                         /*
                          * figure out the byte count for each conversion;
                          * rewrite the format as necessary, set up blank-
-                         * pbb_dump_adding for end of data.
+                         * padding for end of data.
                          */
                         if (*p1 == 'c') {
                                 pr->flags = F_CHAR;
@@ -466,14 +466,14 @@ static void bpad(PR *pr)
 }
 
 static const char conv_str[] ALIGN1 =
-        "\0\\0\0"
-        "\007\\a\0"  /* \a */
-        "\b\\b\0"
-        "\f\\b\0"
-        "\n\\n\0"
-        "\r\\r\0"
-        "\t\\t\0"
-        "\v\\v\0"
+        "\0"  "\\""0""\0"
+        "\007""\\""a""\0"  /* \a */
+        "\b"  "\\""b""\0"
+        "\f"  "\\""f""\0"
+        "\n"  "\\""n""\0"
+        "\r"  "\\""r""\0"
+        "\t"  "\\""t""\0"
+        "\v"  "\\""v""\0"
         ;
 
 
@@ -485,7 +485,7 @@ static void conv_c(PR *pr, unsigned char *p)
         do {
                 if (*p == *str) {
                         ++str;
-                        goto strpr;
+                        goto strpr; /* map e.g. '\n' to "\\n" */
                 }
                 str += 4;
         } while (*str);
@@ -702,8 +702,6 @@ int FAST_FUNC bb_dump_dump(dumper_t *pub_dumper, char **argv)
 void FAST_FUNC bb_dump_add(dumper_t* pub_dumper, const char *fmt)
 {
         const char *p;
-        char *p1;
-        char *p2;
         FS *tfs;
         FU *tfu, **nextfupp;
         const char *savep;
@@ -779,29 +777,42 @@ void FAST_FUNC bb_dump_add(dumper_t* pub_dumper, const char *fmt)
                         }
                 }
                 tfu->fmt = xstrndup(savep, p - savep);
-/*      escape(tfu->fmt); */
-
-                p1 = tfu->fmt;
 
                 /* alphabetic escape sequences have to be done in place */
+                strcpy_and_process_escape_sequences(tfu->fmt, tfu->fmt);
+                /* unknown mappings are not changed: "\z" -> '\\' 'z' */
+                /* trailing backslash, if any, is preserved */
+#if 0
+                char *p1;
+                char *p2;
+                p1 = tfu->fmt;
                 for (p2 = p1;; ++p1, ++p2) {
-                        if (*p1 == '\0') {
-                                *p2 = *p1;
+                        *p2 = *p1;
+                        if (*p1 == '\0')
                                 break;
-                        }
+
                         if (*p1 == '\\') {
-                                const char *cs = conv_str + 4;
-                                ++p1;
+                                const char *cs;
+
+                                p1++;
                                 *p2 = *p1;
+                                if (*p1 == '\0') {
+                                        /* "...\" trailing backslash. Eaten. */
+                                        break;
+                                }
+                                cs = conv_str + 4; /* skip NUL element */
                                 do {
+                                        /* map e.g. "\n" -> '\n' */
                                         if (*p1 == cs[2]) {
                                                 *p2 = cs[0];
                                                 break;
                                         }
                                         cs += 4;
                                 } while (*cs);
+                                /* unknown mappings remove bkslash: "\z" -> 'z' */
                         }
                 }
+#endif
 
                 p++;
         }