modprobe-small: make string buffer code robust; fix help text
together with previous one-liner:
function old new delta
append 70 99 +29
parse_module 295 311 +16
copy_stringbuf 35 36 +1
packed_usage 26545 26540 -5
appendc 27 - -27
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 3/1 up/down: 46/-32) Total: 14 bytes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/modutils/modprobe-small.c b/modutils/modprobe-small.c
index bc80723..e2359d0 100644
--- a/modutils/modprobe-small.c
+++ b/modutils/modprobe-small.c
@@ -44,11 +44,13 @@
char *module_load_options;
smallint dep_bb_seen;
smallint wrote_dep_bb_ok;
- int module_count;
+ unsigned module_count;
int module_found_idx;
- int stringbuf_idx;
- char stringbuf[32 * 1024]; /* some modules have lots of stuff */
+ unsigned stringbuf_idx;
+ unsigned stringbuf_size;
+ char *stringbuf; /* some modules have lots of stuff */
/* for example, drivers/media/video/saa7134/saa7134.ko */
+ /* therefore having a fixed biggish buffer is not wise */
};
#define G (*ptr_to_globals)
#define modinfo (G.modinfo )
@@ -58,16 +60,29 @@
#define module_found_idx (G.module_found_idx )
#define module_load_options (G.module_load_options)
#define stringbuf_idx (G.stringbuf_idx )
+#define stringbuf_size (G.stringbuf_size )
#define stringbuf (G.stringbuf )
#define INIT_G() do { \
SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
} while (0)
+static void append(const char *s)
+{
+ unsigned len = strlen(s);
+ if (stringbuf_idx + len + 15 > stringbuf_size) {
+ stringbuf_size = stringbuf_idx + len + 127;
+ dbg2_error_msg("grow stringbuf to %u", stringbuf_size);
+ stringbuf = xrealloc(stringbuf, stringbuf_size);
+ }
+ memcpy(stringbuf + stringbuf_idx, s, len);
+ stringbuf_idx += len;
+}
static void appendc(char c)
{
- if (stringbuf_idx < sizeof(stringbuf))
- stringbuf[stringbuf_idx++] = c;
+ /* We appendc() only after append(), + 15 trick in append()
+ * makes it unnecessary to check for overflow here */
+ stringbuf[stringbuf_idx++] = c;
}
static void bksp(void)
@@ -76,15 +91,6 @@
stringbuf_idx--;
}
-static void append(const char *s)
-{
- size_t len = strlen(s);
- if (stringbuf_idx + len < sizeof(stringbuf)) {
- memcpy(stringbuf + stringbuf_idx, s, len);
- stringbuf_idx += len;
- }
-}
-
static void reset_stringbuf(void)
{
stringbuf_idx = 0;
@@ -92,7 +98,7 @@
static char* copy_stringbuf(void)
{
- char *copy = xmalloc(stringbuf_idx);
+ char *copy = xzalloc(stringbuf_idx + 1); /* terminating NUL */
return memcpy(copy, stringbuf, stringbuf_idx);
}
@@ -216,7 +222,6 @@
pos = (ptr - module_image);
}
bksp(); /* remove last ' ' */
- appendc('\0');
info->aliases = copy_stringbuf();
replace(info->aliases, '-', '_');
@@ -229,7 +234,6 @@
dbg2_error_msg("dep:'%s'", ptr);
append(ptr);
}
- appendc('\0');
info->deps = copy_stringbuf();
free(module_image);