hexdump: fix hexdump -n1 -ve '8/2 ""' SEGV. Closes 4478

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

1 files changed, 14 insertions, 11 deletions

diff --git a/libbb/dump.c b/libbb/dump.c
index 919fe135c..7e435643b 100644
--- a/libbb/dump.c
+++ b/libbb/dump.c
@@ -71,7 +71,8 @@ static NOINLINE int bb_dump_size(FS *fs)
                          * skip any special chars -- save precision in
                          * case it's a %s format.
                          */
-                        while (strchr(index_str + 1, *++fmt));
+                        while (strchr(index_str + 1, *++fmt))
+                                continue;
                         if (*fmt == '.' && isdigit(*++fmt)) {
                                 prec = atoi(fmt);
                                 while (isdigit(*++fmt))
@@ -99,8 +100,8 @@ static NOINLINE int bb_dump_size(FS *fs)
 static NOINLINE void rewrite(priv_dumper_t *dumper, FS *fs)
 {
         enum { NOTOKAY, USEBCNT, USEPREC } sokay;
-        PR *pr;
         FU *fu;
+        PR *pr;
         char *p1, *p2, *p3;
         char savech, *fmtp;
         const char *byte_count_str;
@@ -292,16 +293,18 @@ static NOINLINE void rewrite(priv_dumper_t *dumper, FS *fs)
          * interprets any data at all, and has no iteration count,
          * repeat it as necessary.
          *
-         * if, rep count is greater than 1, no trailing whitespace
+         * if rep count is greater than 1, no trailing whitespace
          * gets output from the last iteration of the format unit.
          */
         for (fu = fs->nextfu; fu; fu = fu->nextfu) {
-                if (!fu->nextfu && fs->bcnt < dumper->blocksize
-                 && !(fu->flags & F_SETREP) && fu->bcnt
+                if (!fu->nextfu
+                 && fs->bcnt < dumper->blocksize
+                 && !(fu->flags & F_SETREP)
+                 && fu->bcnt
                 ) {
                         fu->reps += (dumper->blocksize - fs->bcnt) / fu->bcnt;
                 }
-                if (fu->reps > 1) {
+                if (fu->reps > 1 && fu->nextpr) {
                         for (pr = fu->nextpr;; pr = pr->nextpr)
                                 if (!pr->nextpr)
                                         break;
@@ -721,7 +724,7 @@ void FAST_FUNC bb_dump_add(dumper_t* pub_dumper, const char *fmt)
         p = fmt;
         for (;;) {
                 p = skip_whitespace(p);
-                if (!*p) {
+                if (*p == '\0') {
                         break;
                 }
 
@@ -749,7 +752,7 @@ void FAST_FUNC bb_dump_add(dumper_t* pub_dumper, const char *fmt)
 
                 /* skip slash and trailing white space */
                 if (*p == '/') {
-                        p = skip_whitespace(++p);
+                        p = skip_whitespace(p + 1);
                 }
 
                 /* byte count */
@@ -763,7 +766,7 @@ void FAST_FUNC bb_dump_add(dumper_t* pub_dumper, const char *fmt)
                         }
                         tfu->bcnt = atoi(savep);
                         /* skip trailing white space */
-                        p = skip_whitespace(++p);
+                        p = skip_whitespace(p + 1);
                 }
 
                 /* format */
@@ -771,7 +774,7 @@ void FAST_FUNC bb_dump_add(dumper_t* pub_dumper, const char *fmt)
                         bb_error_msg_and_die("bad format {%s}", fmt);
                 }
                 for (savep = ++p; *p != '"';) {
-                        if (*p++ == 0) {
+                        if (*p++ == '\0') {
                                 bb_error_msg_and_die("bad format {%s}", fmt);
                         }
                 }
@@ -782,7 +785,7 @@ void FAST_FUNC bb_dump_add(dumper_t* pub_dumper, const char *fmt)
 
                 /* alphabetic escape sequences have to be done in place */
                 for (p2 = p1;; ++p1, ++p2) {
-                        if (!*p1) {
+                        if (*p1 == '\0') {
                                 *p2 = *p1;
                                 break;
                         }