[PATCH] pahole: fix discarded-qualifiers for strchr/strstr

From fa4866e368f5131ddcf6fddccc13203fab88d00d Mon Sep 17 00:00:00 2001
From: Damien Hourtoulle <[email protected]>
Date: Wed, 4 Mar 2026 03:30:31 +0100
Subject: [PATCH] pahole: fix discarded-qualifiers for strchr/strstr.

Glibc 2.43 added C23 const-preserving overloads :
https://sourceware.org/glibc/wiki/Release/2.43.

For the function prototype__new, fix local variable declaration to use
the correct const char* type instead of char*, removing the need to
discard
the const qualifier.

Signed-off-by: Damien Hourtoulle <[email protected]>
---
 btf_encoder.c |  2 +-
 pahole.c      | 19 +++++++++----------
 2 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/btf_encoder.c b/btf_encoder.c
index aa7cd1c..d36984a 100644
--- a/btf_encoder.c
+++ b/btf_encoder.c
@@ -1218,7 +1218,7 @@ static bool str_contains_non_fn_suffix(const char *str) {
                ".cold",
                ".part"
        };
-       char *suffix = strchr(str, '.');
+       const char *suffix = strchr(str, '.');
        int i;

        if (!suffix)
diff --git a/pahole.c b/pahole.c
index 02a0d19..4184703 100644
--- a/pahole.c
+++ b/pahole.c
@@ -2483,7 +2483,7 @@ static int64_t type_instance__int_value(struct
type_instance *instance, const ch
        int byte_offset = 0;

        if (!member) {
-               char *sep = strchr(member_name_orig, '.');
+               const char *sep = strchr(member_name_orig, '.');

                if (!sep)
                        return -1;
@@ -2496,8 +2496,8 @@ static int64_t type_instance__int_value(struct
type_instance *instance, const ch
                char *member_name = member_name_alloc;
                struct type *type = instance->type;

-               sep = member_name_alloc + (sep - member_name_orig);
-               *sep = 0;
+               char *sep_mutable = member_name_alloc + (sep -
member_name_orig);  // sep mutable for the copy
+               *sep_mutable = 0;

                while (1) {
                        member = type__find_member_by_name(type, member_name);
@@ -2510,7 +2510,7 @@ out_free_member_name:
                        type = tag__type(cu__type(cu, member->tag.type));
                        if (type == NULL)
                                goto out_free_member_name;
-                       member_name = sep + 1;
+                       member_name = sep_mutable + 1;
                        sep = strchr(member_name, '.');
                        if (!sep)
                                break;
@@ -2950,7 +2950,7 @@ static struct prototype *prototype__new(const
char *expression)

        strcpy(prototype->name, expression);

-       const char *name = prototype->name;
+       char *name = prototype->name;

        prototype->nr_args = 0;

@@ -2964,10 +2964,9 @@ static struct prototype *prototype__new(const
char *expression)
        if (args_close == NULL)
                goto out_no_closing_parens;

+       *args_open++ = *args_close = '\0';
        char *args = args_open;

-       *args++ = *args_close = '\0';
-
        while (isspace(*args))
                ++args;

@@ -3114,7 +3113,7 @@ static int type__find_type_enum(struct type
*type, struct cu *cu, const char *ty
                return type__add_type_enum(type, te, cu);

        // Now look at a 'virtual enum', i.e. the concatenation of
multiple enums
-       char *sep = strchr(type_enum, '+');
+       const char *sep = strchr(type_enum, '+');

        if (!sep)
                return -1;
@@ -3126,10 +3125,10 @@ static int type__find_type_enum(struct type
*type, struct cu *cu, const char *ty

        int ret = -1;

-       sep = type_enums + (sep - type_enum);
+       char *sep_mutable = type_enums + (sep - type_enum);

        type_enum = type_enums;
-       *sep = '\0';
+       *sep_mutable = '\0';

        while (1) {
                te = cu__find_enumeration_by_name(cu, type_enum, NULL);
-- 
2.53.0