brain-hackers_pepepper-mirror/u-boot-brain
1
0
Fork 0
mirror of https://github.com/brain-hackers/u-boot-brain synced 2024-06-09 23:36:03 +09:00
Code Issues Projects Releases Wiki Activity

cmd: bcb: Use strcmp() instead of strncmp() for string literals

Browse Source 
Quote from https://patchwork.ozlabs.org/patch/1104244/#2210814:

 ----------8<-----------
strncmp() is chosen for the sake of paranoid/defensive programming.
Indeed, strncmp() is not really needed when comparing a variable
with a string literal. We expect strcmp() to behave safely even if the
string variable is not NUL-terminated.

In the same scenario, Linux v5.2-rc7 uses both strcmp() and strncmp(),
but the frequency of strcmp() is higher:

$ git --version
git version 2.22.0
$ (Linux 5.2-rc7) git grep -En 'strncmp\([^"]*"[[:alnum:]]+"' | wc -l
1066
$ (Linux 5.2-rc7) git grep -En 'strcmp\([^"]*"[[:alnum:]]+"' | wc -l
1968

A quick "strcmp vs strncmp" object size test shows that strcmp()
generates smaller memory footprint (gcc-8, x86_64):

$ (U-Boot) size cmd/bcb-strncmp.o cmd/bcb-strcmp.o
   text	   data	    bss	    dec	    hex	filename
   3373	    400	   2048	   5821	   16bd	cmd/bcb-strncmp.o
   3314	    400	   2048	   5762	   1682	cmd/bcb-strcmp.o

So, overall, I agree to use strcmp() whenever variables are compared
with string literals.
 ----------8<-----------

Fixes: db7b7a05b2 ("cmd: Add 'bcb' command to read/modify/write BCB fields")
Reported-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>
Reviewed-by: Igor Opaniuk <igor.opaniuk@gmail.com>
This commit is contained in:
Eugeniu Rosca 2019-07-19 23:26:13 +02:00 committed by Tom Rini
parent e47b73b821
commit 739168cfdc
1 changed files with 11 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
cmd/bcb.c
View File

@ -24,17 +24,17 @@ static struct bootloader_message bcb = { { 0 } };
static int bcb_cmd_get(char *cmd)
{
if (!strncmp(cmd, "load", sizeof("load")))
if (!strcmp(cmd, "load"))
return BCB_CMD_LOAD;
if (!strncmp(cmd, "set", sizeof("set")))
if (!strcmp(cmd, "set"))
return BCB_CMD_FIELD_SET;
if (!strncmp(cmd, "clear", sizeof("clear")))
if (!strcmp(cmd, "clear"))
return BCB_CMD_FIELD_CLEAR;
if (!strncmp(cmd, "test", sizeof("test")))
if (!strcmp(cmd, "test"))
return BCB_CMD_FIELD_TEST;
if (!strncmp(cmd, "store", sizeof("store")))
if (!strcmp(cmd, "store"))
return BCB_CMD_STORE;
if (!strncmp(cmd, "dump", sizeof("dump")))
if (!strcmp(cmd, "dump"))
return BCB_CMD_FIELD_DUMP;
else
return -1;
@ -85,19 +85,19 @@ err:
static int bcb_field_get(char *name, char **field, int *size)
{
if (!strncmp(name, "command", sizeof("command"))) {
if (!strcmp(name, "command")) {
*field = bcb.command;
*size = sizeof(bcb.command);
} else if (!strncmp(name, "status", sizeof("status"))) {
} else if (!strcmp(name, "status")) {
*field = bcb.status;
*size = sizeof(bcb.status);
} else if (!strncmp(name, "recovery", sizeof("recovery"))) {
} else if (!strcmp(name, "recovery")) {
*field = bcb.recovery;
*size = sizeof(bcb.recovery);
} else if (!strncmp(name, "stage", sizeof("stage"))) {
} else if (!strcmp(name, "stage")) {
*field = bcb.stage;
*size = sizeof(bcb.stage);
} else if (!strncmp(name, "reserved", sizeof("reserved"))) {
} else if (!strcmp(name, "reserved")) {
*field = bcb.reserved;
*size = sizeof(bcb.reserved);
} else {