bench: fail early if user inputs invalid value for SECP256K1_BENCH

kevkevinpal commented at 6:15 pm on January 8, 2026: contributor

Description

In this change, the get_iters function was updated to print an error message and then return 0.

In the functions that use get_iters they print the help text and then EXIT_FAILURE

Before

0secp256k1 $ SECP256K1_BENCH_ITERS=abc ./build/bin/bench
1
2Benchmark                     ,    Min(us)    ,    Avg(us)    ,    Max(us)
3
4Floating point exception (core dumped)

After

 0secp256k1 $ SECP256K1_BENCH_ITERS=abc ./build/bin/bench
 1
 2Invalid value for SECP256K1_BENCH_ITERS must be a positive integer: abc
 3
 4Benchmarks the following algorithms:
 5    - ECDSA signing/verification
 6    - ECDH key exchange (optional module)
 7    - Schnorr signatures (optional module)
 8    - ElligatorSwift (optional module)
 9
10The default number of iterations for each benchmark is 20000. This can be
11customized using the SECP256K1_BENCH_ITERS environment variable.
12
13Usage: ./bench [args]
14By default, all benchmarks will be run.
15args:
16    help              : display this help and exit
17    ecdsa             : all ECDSA algorithms--sign, verify, recovery (if enabled)
18    ecdsa_sign        : ECDSA siging algorithm
19    ecdsa_verify      : ECDSA verification algorithm
20    ec                : all EC public key algorithms (keygen)
21    ec_keygen         : EC public key generation
22    ecdh              : ECDH key exchange algorithm
23    schnorrsig        : all Schnorr signature algorithms (sign, verify)
24    schnorrsig_sign   : Schnorr sigining algorithm
25    schnorrsig_verify : Schnorr verification algorithm
26    ellswift          : all ElligatorSwift benchmarks (encode, decode, keygen, ecdh)
27    ellswift_encode   : ElligatorSwift encoding
28    ellswift_decode   : ElligatorSwift decoding
29    ellswift_keygen   : ElligatorSwift key generation
30    ellswift_ecdh     : ECDH on ElligatorSwift keys

kevkevinpal force-pushed on Jan 8, 2026

real-or-random added the label tweak/refactor on Jan 8, 2026

in src/bench.h:156 in 331bb48bed

149@@ -150,7 +150,13 @@ static int have_invalid_args(int argc, char** argv, char** valid_args, size_t n)
150 static int get_iters(int default_iters) {
151     char* env = getenv("SECP256K1_BENCH_ITERS");
152     if (env) {
153-        return strtol(env, NULL, 0);
154+        char* endptr;
155+        long int iters = strtol(env, &endptr, 0);
156+        if (*endptr != '\0' || iters == 0) {
157+            printf("Invalid value for SECP256K1_BENCH_ITERS must be a positive integer: %s\n\n", env);

real-or-random commented at 8:30 am on January 9, 2026:

0            printf("Error: Value of SECP256K1_BENCH_ITERS is not a positive integer: %s\n\n", env);

nit:
I think the wording “invalid value …. must be a positive integer” is a bit confusing.

kevkevinpal commented at 2:20 pm on January 9, 2026:

Thanks for the review l, I took your suggestion and fixed it in a02ea3566c28e1e919ca8e037c42dad4ec223138

in src/bench.h:155 in 331bb48bed

149@@ -150,7 +150,13 @@ static int have_invalid_args(int argc, char** argv, char** valid_args, size_t n)
150 static int get_iters(int default_iters) {
151     char* env = getenv("SECP256K1_BENCH_ITERS");
152     if (env) {
153-        return strtol(env, NULL, 0);
154+        char* endptr;
155+        long int iters = strtol(env, &endptr, 0);
156+        if (*endptr != '\0' || iters == 0) {

real-or-random commented at 8:32 am on January 9, 2026:

0        if (*endptr != '\0' || iters <= 0) {

kevkevinpal commented at 2:19 pm on January 9, 2026:

Thanks for the review! I fixed this in a02ea3566c28e1e919ca8e037c42dad4ec223138

hebasto commented at 4:55 pm on January 9, 2026:

Right. Otherwise, negative values are accepted:

 0$ SECP256K1_BENCH_ITERS=-1 ./build/bin/bench
 1Benchmark                     ,    Min(us)    ,    Avg(us)    ,    Max(us)    
 2
 3ecdsa_verify                  ,     0.0       ,    -0.300     ,    -1.00   
 4ecdsa_sign                    ,     0.0       ,    -0.100     ,    -1.00   
 5ec_keygen                     ,     0.0       ,     0.0       ,     0.0    
 6ecdh                          ,     0.0       ,     0.0       ,     0.0    
 7ecdsa_recover                 ,     0.0       ,    -0.100     ,    -1.00   
 8schnorrsig_sign               ,     0.0       ,     0.0       ,     0.0    
 9schnorrsig_verify             ,     0.0       ,     0.0       ,     0.0    
10ellswift_encode               ,     0.0       ,    -0.200     ,    -1.00   
11ellswift_decode               ,     0.0       ,     0.0       ,     0.0    
12ellswift_keygen               ,     0.0       ,    -0.100     ,    -1.00   
13ellswift_ecdh                 ,     0.0       ,    -0.100     ,    -1.00

real-or-random commented at 8:32 am on January 9, 2026: contributor

ACK mod nits

kevkevinpal force-pushed on Jan 9, 2026

hebasto approved

hebasto commented at 4:56 pm on January 9, 2026: member

ACK a02ea3566c28e1e919ca8e037c42dad4ec223138, I have reviewed the code and it looks OK. Tested on Ubuntu 25.10.

real-or-random commented at 1:34 pm on January 13, 2026: contributor

Needs rebase (on your own stuff) :)

kevkevinpal force-pushed on Jan 23, 2026

kevkevinpal commented at 1:05 pm on January 23, 2026: contributor

Needs rebase (on your own stuff) :)

Sorry was traveling for a bit, rebased to c09215f

bench: fail early if user inputs invalid value for SECP256K1_BENCH_ITERS

In this change the get_iters function was updated to print an error
message and then return 0. In the functions that use get_iters they
print the help text and then EXIT_FAILURE

c09215f7af

kevkevinpal force-pushed on Jan 23, 2026

hebasto approved

hebasto commented at 1:20 pm on January 23, 2026: member

re-ACK c09215f7af9db3e34427ff9a5633e7978acabca1.

real-or-random approved

real-or-random commented at 1:29 pm on January 23, 2026: contributor

utACK c09215f7af9db3e34427ff9a5633e7978acabca1

real-or-random merged this on Jan 23, 2026

real-or-random closed this on Jan 23, 2026

bench: fail early if user inputs invalid value for SECP256K1_BENCH_ITERS #1796

Description

Before

After