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SubjectRE: [PATCH v8 02/31] kallsyms: avoid hardcoding buffer size
Date
From: Miguel Ojeda
> Sent: 02 August 2022 02:50
>
> From: Boqun Feng <boqun.feng@gmail.com>
>
> This introduces `KSYM_NAME_LEN_BUFFER` in place of the previously
> hardcoded size of the input buffer.
>
> It will also make it easier to update the size in a single place
> in a later patch.
>
> Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
> Co-developed-by: Miguel Ojeda <ojeda@kernel.org>
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
> ---
> scripts/kallsyms.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
> index 52f5488c61bc..f3c5a2623f71 100644
> --- a/scripts/kallsyms.c
> +++ b/scripts/kallsyms.c
> @@ -27,8 +27,14 @@
>
> #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof(arr[0]))
>
> +#define _stringify_1(x) #x
> +#define _stringify(x) _stringify_1(x)
> +
> #define KSYM_NAME_LEN 128
>
> +/* A substantially bigger size than the current maximum. */
> +#define KSYM_NAME_LEN_BUFFER 499
> +
> struct sym_entry {
> unsigned long long addr;
> unsigned int len;
> @@ -198,13 +204,13 @@ static void check_symbol_range(const char *sym, unsigned long long addr,
>
> static struct sym_entry *read_symbol(FILE *in)
> {
> - char name[500], type;
> + char name[KSYM_NAME_LEN_BUFFER+1], type;
> unsigned long long addr;
> unsigned int len;
> struct sym_entry *sym;
> int rc;
>
> - rc = fscanf(in, "%llx %c %499s\n", &addr, &type, name);
> + rc = fscanf(in, "%llx %c %" _stringify(KSYM_NAME_LEN_BUFFER) "s\n", &addr, &type, name);

Think I'd use "%*s" - simpler.
Although I normally completely avoid scanf() - too easy to get wrong.

David

> if (rc != 3) {
> if (rc != EOF && fgets(name, sizeof(name), in) == NULL)
> fprintf(stderr, "Read error or end of file.\n");
> --
> 2.37.1

-
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