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authorGravatar Denys Vlasenko <vda.linux@googlemail.com>2017-10-05 14:06:49 +0200
committerGravatar Denys Vlasenko <vda.linux@googlemail.com>2017-10-05 14:06:49 +0200
commit318c8114deb4acd10e74398c5fb4c0068c86bcb1 (patch)
tree3405d5987b435fcdac87eaf8fa8d74bf5dd0fab8
parent6e2beb7dfee1a4542eca1a6e8c0f33486d9d5fb9 (diff)
downloadbusybox-318c8114deb4acd10e74398c5fb4c0068c86bcb1.tar.gz
busybox-318c8114deb4acd10e74398c5fb4c0068c86bcb1.tar.bz2
free: make it NOFORK
function old new delta parse_cached_kb - 85 +85 free_main 580 537 -43 ------------------------------------------------------------------------------ (add/remove: 1/0 grow/shrink: 0/1 up/down: 85/-43) Total: 42 bytes Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--NOFORK_NOEXEC.lst2
-rw-r--r--procps/free.c51
2 files changed, 24 insertions, 29 deletions
diff --git a/NOFORK_NOEXEC.lst b/NOFORK_NOEXEC.lst
index 4e53d7204..72c33ddd7 100644
--- a/NOFORK_NOEXEC.lst
+++ b/NOFORK_NOEXEC.lst
@@ -144,7 +144,7 @@ flash_unlock - hardware
flashcp - hardware
flock - spawner, changes state (file locks), let's play safe and not be noexec
fold - noexec. runner
-free - noexec. nofork candidate(struct globals, needs to close /proc/meminfo fd)
+free - NOFORK
freeramdisk - noexec. leaks: open+ioctl_or_perror_and_die
fsck - interactive, longterm
fsck.minix - needs ^C
diff --git a/procps/free.c b/procps/free.c
index b57e4a322..fa423cfa5 100644
--- a/procps/free.c
+++ b/procps/free.c
@@ -15,7 +15,7 @@
//config: memory in the system, as well as the buffers used by the kernel.
//config: The shared memory column should be ignored; it is obsolete.
-//applet:IF_FREE(APPLET_NOEXEC(free, free, BB_DIR_USR_BIN, BB_SUID_DROP, free))
+//applet:IF_FREE(APPLET_NOFORK(free, free, BB_DIR_USR_BIN, BB_SUID_DROP, free))
//kbuild:lib-$(CONFIG_FREE) += free.o
@@ -40,25 +40,21 @@
struct globals {
unsigned mem_unit;
#if ENABLE_DESKTOP
- unsigned unit_steps;
-# define G_unit_steps G.unit_steps
+ uint8_t unit_steps;
+# define G_unit_steps g->unit_steps
#else
# define G_unit_steps 10
#endif
-} FIX_ALIASING;
-#define G (*(struct globals*)bb_common_bufsiz1)
-#define INIT_G() do { \
- setup_common_bufsiz(); \
- /* NB: noexec applet - globals not zeroed */ \
-} while (0)
+};
+/* Because of NOFORK, "globals" are not in global data */
-
-static unsigned long long scale(unsigned long d)
+static unsigned long long scale(struct globals *g, unsigned long d)
{
- return ((unsigned long long)d * G.mem_unit) >> G_unit_steps;
+ return ((unsigned long long)d * g->mem_unit) >> G_unit_steps;
}
-static unsigned long parse_cached_kb(void)
+/* NOINLINE reduces main() stack usage, which makes code smaller (on x86 at least) */
+static NOINLINE unsigned long parse_cached_kb(void)
{
char buf[60]; /* actual lines we expect are ~30 chars or less */
FILE *fp;
@@ -69,8 +65,8 @@ static unsigned long parse_cached_kb(void)
if (sscanf(buf, "Cached: %lu %*s\n", &cached) == 1)
break;
}
- if (ENABLE_FEATURE_CLEAN_UP)
- fclose(fp);
+ /* Have to close because of NOFORK */
+ fclose(fp);
return cached;
}
@@ -78,11 +74,10 @@ static unsigned long parse_cached_kb(void)
int free_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int free_main(int argc UNUSED_PARAM, char **argv IF_NOT_DESKTOP(UNUSED_PARAM))
{
+ struct globals G;
struct sysinfo info;
unsigned long long cached;
- INIT_G();
-
#if ENABLE_DESKTOP
G.unit_steps = 10;
if (argv[1] && argv[1][0] == '-') {
@@ -123,12 +118,12 @@ int free_main(int argc UNUSED_PARAM, char **argv IF_NOT_DESKTOP(UNUSED_PARAM))
#define FIELDS_2 (FIELDS_6 + 4*6)
printf(FIELDS_6,
- scale(info.totalram), //total
- scale(info.totalram - info.freeram), //used
- scale(info.freeram), //free
- scale(info.sharedram), //shared
- scale(info.bufferram), //buffers
- scale(cached) //cached
+ scale(&G, info.totalram), //total
+ scale(&G, info.totalram - info.freeram), //used
+ scale(&G, info.freeram), //free
+ scale(&G, info.sharedram), //shared
+ scale(&G, info.bufferram), //buffers
+ scale(&G, cached) //cached
);
/* Show alternate, more meaningful busy/free numbers by counting
* buffer cache as free memory. */
@@ -136,15 +131,15 @@ int free_main(int argc UNUSED_PARAM, char **argv IF_NOT_DESKTOP(UNUSED_PARAM))
cached += info.freeram;
cached += info.bufferram;
printf(FIELDS_2,
- scale(info.totalram - cached), //used
- scale(cached) //free
+ scale(&G, info.totalram - cached), //used
+ scale(&G, cached) //free
);
#if BB_MMU
printf("Swap: ");
printf(FIELDS_3,
- scale(info.totalswap), //total
- scale(info.totalswap - info.freeswap), //used
- scale(info.freeswap) //free
+ scale(&G, info.totalswap), //total
+ scale(&G, info.totalswap - info.freeswap), //used
+ scale(&G, info.freeswap) //free
);
#endif
return EXIT_SUCCESS;