[PATCH] rt-tests: hackbench: drop incorrect and unnecessary usage of optind

[PATCH] rt-tests: hackbench: drop incorrect and unnecessary usage of optind

[Nam Cao]

Variable "optind" is used as the last argument of getopt_long(). This
means it "is set to the index of the long option relative to longopts"
(from man page). NULL check is then performed on argv[optind], which is
not valid, because in this case, optind is not an index to argv[].

There is another "optind" which is a global variable, which actually
holds the index to argv[]. This is likely the actual intention here. By
locally define another "optind", the "real optind" is shadowed in this
scope.

Furthermore, the original optind "is the index of the next element to
be processed in argv" (from man page), not the index to the current
element. So doing NULL-check on argv[optind] with the "original optind"
is also not valid.

There is no reason to do this NULL-check, since argv[optind] is not even
read. Only optarg is read, which is never a NULL pointer in this case.

Delete this incorrect and unnecessary "optind".

Signed-off-by: Nam Cao <namcao@linutronix.de>
---
 src/hackbench/hackbench.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/src/hackbench/hackbench.c b/src/hackbench/hackbench.c
index 4430db0..d4924b3 100644
--- a/src/hackbench/hackbench.c
+++ b/src/hackbench/hackbench.c
@@ -405,8 +405,6 @@ static unsigned int group(childinfo_t *child,
 static void process_options(int argc, char *argv[])
 {
 	for(;;) {
-		int optind = 0;
-
 		static struct option longopts[] = {
 			{"fds",		required_argument,	NULL, 'f'},
 			{"fifo",	no_argument,		NULL, 'F'},
@@ -422,13 +420,13 @@ static void process_options(int argc, char *argv[])
 		};
 
 		int c = getopt_long(argc, argv, "f:Fg:hl:pis:TP",
-				    longopts, &optind);
+				    longopts, NULL);
 		if (c == -1) {
 			break;
 		}
 		switch (c) {
 		case 'f':
-			if (!(argv[optind] && (num_fds = atoi(optarg)) > 0)) {
+			if ((num_fds = atoi(optarg)) <= 0) {
 				fprintf(stderr, "%s: --fds|-f requires an integer > 0\n", argv[0]);
 				print_usage_exit(1);
 			}
@@ -437,7 +435,7 @@ static void process_options(int argc, char *argv[])
 			fifo = 1;
 			break;
 		case 'g':
-			if (!(argv[optind] && (num_groups = atoi(optarg)) > 0)) {
+			if ((num_groups = atoi(optarg)) <= 0) {
 				fprintf(stderr, "%s: --groups|-g requires an integer > 0\n", argv[0]);
 				print_usage_exit(1);
 			}
@@ -446,7 +444,7 @@ static void process_options(int argc, char *argv[])
 			print_usage_exit(0);
 			break;
 		case 'l':
-			if (!(argv[optind] && (loops = atoi(optarg)) > 0)) {
+			if ((loops = atoi(optarg)) <= 0) {
 				fprintf(stderr, "%s: --loops|-l requires an integer > 0\n", argv[0]);
 				print_usage_exit(1);
 			}
-- 
2.39.2

Re: [PATCH] rt-tests: hackbench: drop incorrect and unnecessary usage of optind

[Sebastian Andrzej Siewior]

On 2024-04-02 19:46:59 [+0200], Nam Cao wrote:
> Variable "optind" is used as the last argument of getopt_long(). This
> means it "is set to the index of the long option relative to longopts"
> (from man page). NULL check is then performed on argv[optind], which is
> not valid, because in this case, optind is not an index to argv[].
> 
> There is another "optind" which is a global variable, which actually
> holds the index to argv[]. This is likely the actual intention here. By
> locally define another "optind", the "real optind" is shadowed in this
> scope.
> 
> Furthermore, the original optind "is the index of the next element to
> be processed in argv" (from man page), not the index to the current
> element. So doing NULL-check on argv[optind] with the "original optind"
> is also not valid.
> 
> There is no reason to do this NULL-check, since argv[optind] is not even
> read. Only optarg is read, which is never a NULL pointer in this case.
> 
> Delete this incorrect and unnecessary "optind".
> 
> Signed-off-by: Nam Cao <namcao@linutronix.de>

Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

Sebastian

Re: [PATCH] rt-tests: hackbench: drop incorrect and unnecessary usage of optind

[John Kacur]

On Tue, 2 Apr 2024, Nam Cao wrote:

> Variable "optind" is used as the last argument of getopt_long(). This
> means it "is set to the index of the long option relative to longopts"
> (from man page). NULL check is then performed on argv[optind], which is
> not valid, because in this case, optind is not an index to argv[].
> 
> There is another "optind" which is a global variable, which actually
> holds the index to argv[]. This is likely the actual intention here. By
> locally define another "optind", the "real optind" is shadowed in this
> scope.
> 
> Furthermore, the original optind "is the index of the next element to
> be processed in argv" (from man page), not the index to the current
> element. So doing NULL-check on argv[optind] with the "original optind"
> is also not valid.
> 
> There is no reason to do this NULL-check, since argv[optind] is not even
> read. Only optarg is read, which is never a NULL pointer in this case.
> 
> Delete this incorrect and unnecessary "optind".
> 
> Signed-off-by: Nam Cao <namcao@linutronix.de>
> ---
>  src/hackbench/hackbench.c | 10 ++++------
>  1 file changed, 4 insertions(+), 6 deletions(-)
> 
> diff --git a/src/hackbench/hackbench.c b/src/hackbench/hackbench.c
> index 4430db0..d4924b3 100644
> --- a/src/hackbench/hackbench.c
> +++ b/src/hackbench/hackbench.c
> @@ -405,8 +405,6 @@ static unsigned int group(childinfo_t *child,
>  static void process_options(int argc, char *argv[])
>  {
>  	for(;;) {
> -		int optind = 0;
> -
>  		static struct option longopts[] = {
>  			{"fds",		required_argument,	NULL, 'f'},
>  			{"fifo",	no_argument,		NULL, 'F'},
> @@ -422,13 +420,13 @@ static void process_options(int argc, char *argv[])
>  		};
>  
>  		int c = getopt_long(argc, argv, "f:Fg:hl:pis:TP",
> -				    longopts, &optind);
> +				    longopts, NULL);
>  		if (c == -1) {
>  			break;
>  		}
>  		switch (c) {
>  		case 'f':
> -			if (!(argv[optind] && (num_fds = atoi(optarg)) > 0)) {
> +			if ((num_fds = atoi(optarg)) <= 0) {
>  				fprintf(stderr, "%s: --fds|-f requires an integer > 0\n", argv[0]);
>  				print_usage_exit(1);
>  			}
> @@ -437,7 +435,7 @@ static void process_options(int argc, char *argv[])
>  			fifo = 1;
>  			break;
>  		case 'g':
> -			if (!(argv[optind] && (num_groups = atoi(optarg)) > 0)) {
> +			if ((num_groups = atoi(optarg)) <= 0) {
>  				fprintf(stderr, "%s: --groups|-g requires an integer > 0\n", argv[0]);
>  				print_usage_exit(1);
>  			}
> @@ -446,7 +444,7 @@ static void process_options(int argc, char *argv[])
>  			print_usage_exit(0);
>  			break;
>  		case 'l':
> -			if (!(argv[optind] && (loops = atoi(optarg)) > 0)) {
> +			if ((loops = atoi(optarg)) <= 0) {
>  				fprintf(stderr, "%s: --loops|-l requires an integer > 0\n", argv[0]);
>  				print_usage_exit(1);
>  			}
> -- 


Signed-off-by: John Kacur <jkacur@redhat.com>

Re: [PATCH] rt-tests: hackbench: drop incorrect and unnecessary usage of optind

[John Kacur]

On Fri, 5 Apr 2024, Sebastian Andrzej Siewior wrote:

> On 2024-04-02 19:46:59 [+0200], Nam Cao wrote:
> > Variable "optind" is used as the last argument of getopt_long(). This
> > means it "is set to the index of the long option relative to longopts"
> > (from man page). NULL check is then performed on argv[optind], which is
> > not valid, because in this case, optind is not an index to argv[].
> > 
> > There is another "optind" which is a global variable, which actually
> > holds the index to argv[]. This is likely the actual intention here. By
> > locally define another "optind", the "real optind" is shadowed in this
> > scope.
> > 
> > Furthermore, the original optind "is the index of the next element to
> > be processed in argv" (from man page), not the index to the current
> > element. So doing NULL-check on argv[optind] with the "original optind"
> > is also not valid.
> > 
> > There is no reason to do this NULL-check, since argv[optind] is not even
> > read. Only optarg is read, which is never a NULL pointer in this case.
> > 
> > Delete this incorrect and unnecessary "optind".
> > 
> > Signed-off-by: Nam Cao <namcao@linutronix.de>
> 
> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> 
> Sebastian
> 
> 

Added your Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
to the patch, thanks