[PATCH 2/2] libbb: add a function to make a copy of a region of memory
Ron Yorston
rmy at frippery.org
Thu Jul 16 09:51:57 UTC 2015
Introduce a library routine to package the idiom:
p = xmalloc(b, n);
memcpy(p, b, n);
and use it where possible. The example in traceroute used xzalloc
but it didn't need to.
function old new delta
xmemdup - 32 +32
last_main 834 826 -8
make_device 2321 2311 -10
common_traceroute_main 3698 3685 -13
readtoken1 3182 3168 -14
procps_scan 1222 1206 -16
forkchild 655 638 -17
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 0/6 up/down: 32/-78) Total: -46 bytes
Signed-off-by: Ron Yorston <rmy at pobox.com>
---
include/libbb.h | 1 +
libbb/procps.c | 3 +--
libbb/xfuncs_printf.c | 5 +++++
miscutils/last_fancy.c | 4 ++--
networking/traceroute.c | 11 +----------
networking/udhcp/d6_dhcpc.c | 2 +-
shell/ash.c | 5 ++---
util-linux/mdev.c | 2 +-
8 files changed, 14 insertions(+), 19 deletions(-)
diff --git a/include/libbb.h b/include/libbb.h
index f0ac1f5..54d01b7 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -673,6 +673,7 @@ uint16_t inet_cksum(uint16_t *addr, int len) FAST_FUNC;
char *xstrdup(const char *s) FAST_FUNC RETURNS_MALLOC;
char *xstrndup(const char *s, int n) FAST_FUNC RETURNS_MALLOC;
+void *xmemdup(const void *s, int n) FAST_FUNC RETURNS_MALLOC;
void overlapping_strcpy(char *dst, const char *src) FAST_FUNC;
char *safe_strncpy(char *dst, const char *src, size_t size) FAST_FUNC;
char *strncpy_IFNAMSIZ(char *dst, const char *src) FAST_FUNC;
diff --git a/libbb/procps.c b/libbb/procps.c
index 3d335b3..71ad071 100644
--- a/libbb/procps.c
+++ b/libbb/procps.c
@@ -554,8 +554,7 @@ procps_status_t* FAST_FUNC procps_scan(procps_status_t* sp, int flags)
break;
if (flags & PSSCAN_ARGVN) {
sp->argv_len = n;
- sp->argv0 = xmalloc(n + 1);
- memcpy(sp->argv0, buf, n + 1);
+ sp->argv0 = xmemdup(buf, n + 1);
/* sp->argv0[n] = '\0'; - buf has it */
} else {
sp->argv_len = 0;
diff --git a/libbb/xfuncs_printf.c b/libbb/xfuncs_printf.c
index e4ac6a0..5f769c9 100644
--- a/libbb/xfuncs_printf.c
+++ b/libbb/xfuncs_printf.c
@@ -112,6 +112,11 @@ char* FAST_FUNC xstrndup(const char *s, int n)
return memcpy(t, s, n);
}
+void * FAST_FUNC xmemdup(const void *s, int n)
+{
+ return memcpy(xmalloc(n), s, n);
+}
+
// Die if we can't open a file and return a FILE* to it.
// Notice we haven't got xfread(), This is for use with fscanf() and friends.
FILE* FAST_FUNC xfopen(const char *path, const char *mode)
diff --git a/miscutils/last_fancy.c b/miscutils/last_fancy.c
index 8194e31..e56e0ba 100644
--- a/miscutils/last_fancy.c
+++ b/miscutils/last_fancy.c
@@ -233,7 +233,7 @@ int last_main(int argc UNUSED_PARAM, char **argv)
break;
}
/* add_entry */
- llist_add_to(&zlist, memcpy(xmalloc(sizeof(ut)), &ut, sizeof(ut)));
+ llist_add_to(&zlist, xmemdup(&ut, sizeof(ut)));
break;
case USER_PROCESS: {
int show;
@@ -275,7 +275,7 @@ int last_main(int argc UNUSED_PARAM, char **argv)
show_entry(&ut, state, boot_time);
}
/* add_entry */
- llist_add_to(&zlist, memcpy(xmalloc(sizeof(ut)), &ut, sizeof(ut)));
+ llist_add_to(&zlist, xmemdup(&ut, sizeof(ut)));
break;
}
}
diff --git a/networking/traceroute.c b/networking/traceroute.c
index 97a7a19..12ba614 100644
--- a/networking/traceroute.c
+++ b/networking/traceroute.c
@@ -387,15 +387,6 @@ struct globals {
#define outudp ((struct udphdr *)(outip + 1))
-/* libbb candidate? tftp uses this idiom too */
-static len_and_sockaddr* dup_sockaddr(const len_and_sockaddr *lsa)
-{
- len_and_sockaddr *new_lsa = xzalloc(LSA_LEN_SIZE + lsa->len);
- memcpy(new_lsa, lsa, LSA_LEN_SIZE + lsa->len);
- return new_lsa;
-}
-
-
static int
wait_for_reply(len_and_sockaddr *from_lsa, struct sockaddr *to, unsigned *timestamp_us, int *left_ms)
{
@@ -1074,7 +1065,7 @@ common_traceroute_main(int op, char **argv)
printf(" from %s", source);
printf(", %d hops max, %d byte packets\n", max_ttl, packlen);
- from_lsa = dup_sockaddr(dest_lsa);
+ from_lsa = xmemdup(dest_lsa, LSA_LEN_SIZE + dest_lsa->len);
lastaddr = xzalloc(dest_lsa->len);
to = xzalloc(dest_lsa->len);
seq = 0;
diff --git a/networking/udhcp/d6_dhcpc.c b/networking/udhcp/d6_dhcpc.c
index 044f046..4e9b705 100644
--- a/networking/udhcp/d6_dhcpc.c
+++ b/networking/udhcp/d6_dhcpc.c
@@ -118,7 +118,7 @@ static void *d6_copy_option(uint8_t *option, uint8_t *option_end, unsigned code)
uint8_t *opt = d6_find_option(option, option_end, code);
if (!opt)
return opt;
- return memcpy(xmalloc(opt[3] + 4), opt, opt[3] + 4);
+ return xmemdup(opt, opt[3] + 4);
}
static void *d6_store_blob(void *dst, const void *src, unsigned len)
diff --git a/shell/ash.c b/shell/ash.c
index 6627cec..a12408c 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -4751,7 +4751,7 @@ forkchild(struct job *jp, union node *n, int mode)
* Our solution: ONLY bare $(trap) or `trap` is special.
*/
/* Save trap handler strings for trap builtin to print */
- trap_ptr = memcpy(xmalloc(sizeof(trap)), trap, sizeof(trap));
+ trap_ptr = xmemdup(trap, sizeof(trap));
/* Fall through into clearing traps */
}
clear_traps();
@@ -11627,8 +11627,7 @@ parsebackq: {
str = NULL;
savelen = out - (char *)stackblock();
if (savelen > 0) {
- str = ckmalloc(savelen);
- memcpy(str, stackblock(), savelen);
+ str = xmemdup(stackblock(), savelen);
}
savehandler = exception_handler;
exception_handler = &jmploc;
diff --git a/util-linux/mdev.c b/util-linux/mdev.c
index ca4b915..662e8ab 100644
--- a/util-linux/mdev.c
+++ b/util-linux/mdev.c
@@ -471,7 +471,7 @@ static const struct rule *next_rule(void)
if (G.parser) {
parse_next_rule();
if (G.rule_vec) { /* mdev -s */
- rule = memcpy(xmalloc(sizeof(G.cur_rule)), &G.cur_rule, sizeof(G.cur_rule));
+ rule = xmemdup(&G.cur_rule, sizeof(G.cur_rule));
G.rule_vec = xrealloc_vector(G.rule_vec, 4, G.rule_idx);
G.rule_vec[G.rule_idx++] = rule;
dbg3("> G.rule_vec[G.rule_idx:%d]=%p", G.rule_idx, G.rule_vec[G.rule_idx]);
--
2.4.3
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