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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123// SPDX-License-Identifier: GPL-2.0#include <linux/btf.h>#include <linux/kernel.h>#include <linux/slab.h>
#include "trace_btf.h"
/* * Find a function proto type by name, and return the btf_type with its btf * in *@btf_p. Return NULL if not found. * Note that caller has to call btf_put(*@btf_p) after using the btf_type. */const struct btf_type *btf_find_func_proto(const char *func_name, struct btf **btf_p){ const struct btf_type *t; s32 id;
id = bpf_find_btf_id(func_name, BTF_KIND_FUNC, btf_p); if (id < 0) return NULL;
/* Get BTF_KIND_FUNC type */ t = btf_type_by_id(*btf_p, id); if (!t || !btf_type_is_func(t)) goto err;
/* The type of BTF_KIND_FUNC is BTF_KIND_FUNC_PROTO */ t = btf_type_by_id(*btf_p, t->type); if (!t || !btf_type_is_func_proto(t)) goto err;
return t;err: btf_put(*btf_p); return NULL;}
/* * Get function parameter with the number of parameters. * This can return NULL if the function has no parameters. * It can return -EINVAL if the @func_proto is not a function proto type. */const struct btf_param *btf_get_func_param(const struct btf_type *func_proto, s32 *nr){ if (!btf_type_is_func_proto(func_proto)) return ERR_PTR(-EINVAL);
*nr = btf_type_vlen(func_proto); if (*nr > 0) return (const struct btf_param *)(func_proto + 1); else return NULL;}
#define BTF_ANON_STACK_MAX 16
struct btf_anon_stack { u32 tid; u32 offset;};
/* * Find a member of data structure/union by name and return it. * Return NULL if not found, or -EINVAL if parameter is invalid. * If the member is an member of anonymous union/structure, the offset * of that anonymous union/structure is stored into @anon_offset. Caller * can calculate the correct offset from the root data structure by * adding anon_offset to the member's offset. */const struct btf_member *btf_find_struct_member(struct btf *btf, const struct btf_type *type, const char *member_name, u32 *anon_offset){ struct btf_anon_stack *anon_stack; const struct btf_member *member; u32 tid, cur_offset = 0; const char *name; int i, top = 0;
anon_stack = kzalloc_objs(*anon_stack, BTF_ANON_STACK_MAX); if (!anon_stack) return ERR_PTR(-ENOMEM);
retry: if (!btf_type_is_struct(type)) { member = ERR_PTR(-EINVAL); goto out; }
for_each_member(i, type, member) { if (!member->name_off) { /* Anonymous union/struct: push it for later use */ if (btf_type_skip_modifiers(btf, member->type, &tid) && top < BTF_ANON_STACK_MAX) { anon_stack[top].tid = tid; anon_stack[top++].offset = cur_offset + member->offset; } } else { name = btf_name_by_offset(btf, member->name_off); if (name && !strcmp(member_name, name)) { if (anon_offset) *anon_offset = cur_offset; goto out; } } } if (top > 0) { /* Pop from the anonymous stack and retry */ tid = anon_stack[--top].tid; cur_offset = anon_stack[top].offset; type = btf_type_by_id(btf, tid); goto retry; } member = NULL;
out: kfree(anon_stack); return member;}