The implementation of strjoin is a bit suboptimal. The destination
string is traversed from the beginning due to strcat and we have a
left-over separator at the end, while it should only be in-between.
Fix this.
Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
---
include/string.h | 1 +
lib/string.c | 15 +++++++++++----
2 files changed, 12 insertions(+), 4 deletions(-)
diff --git a/include/string.h b/include/string.h
index 2cc727fd1d7a..596440ca8164 100644
--- a/include/string.h
+++ b/include/string.h
@@ -4,6 +4,7 @@
#include <linux/string.h>
+void *mempcpy(void *dest, const void *src, size_t count);
int strtobool(const char *str, int *val);
char *strsep_unescaped(char **, const char *);
char *stpcpy(char *dest, const char *src);
diff --git a/lib/string.c b/lib/string.c
index a500e8a3d1ba..edd36da4d4f2 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -603,6 +603,11 @@ void *__memcpy(void * dest, const void *src, size_t count)
__alias(__default_memcpy);
#endif
+void *mempcpy(void *dest, const void *src, size_t count)
+{
+ return memcpy(dest, src, count) + count;
+}
+EXPORT_SYMBOL(mempcpy);
#ifndef __HAVE_ARCH_MEMMOVE
/**
@@ -943,7 +948,7 @@ char *strjoin(const char *separator, char **arr, size_t arrlen)
{
size_t separatorlen;
int len = 1; /* '\0' */
- char *buf;
+ char *buf, *p;
int i;
separatorlen = strlen(separator);
@@ -951,12 +956,14 @@ char *strjoin(const char *separator, char **arr, size_t arrlen)
for (i = 0; i < arrlen; i++)
len += strlen(arr[i]) + separatorlen;
- buf = xzalloc(len);
+ p = buf = xmalloc(len);
for (i = 0; i < arrlen; i++) {
- strcat(buf, arr[i]);
- strcat(buf, separator);
+ p = stpcpy(p, arr[i]);
+ p = mempcpy(p, separator, separatorlen);
}
+ p[-separatorlen] = '\0';
+
return buf;
}
--
2.30.2
