Re: [PATCH 8/8] tools, perf: Add asprintf replacement

[Jiri Olsa]

On Fri, Sep 26, 2014 at 04:37:16PM -0700, Andi Kleen wrote:
> From: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> 
> asprintf corrupts memory on some older glibc versions.
> Provide a replacement. This fixes various segfaults
> with --branch-history on older Fedoras.
> 
> Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> ---
>  tools/perf/Makefile.perf    |  1 +
>  tools/perf/builtin-report.c |  3 ++-
>  tools/perf/util/asprintf.c  | 28 ++++++++++++++++++++++++++++
>  3 files changed, 31 insertions(+), 1 deletion(-)
>  create mode 100644 tools/perf/util/asprintf.c
> 
> diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
> index 171f4e6..5bdb960 100644
> --- a/tools/perf/Makefile.perf
> +++ b/tools/perf/Makefile.perf
> @@ -377,6 +377,7 @@ LIB_OBJS += $(OUTPUT)util/vdso.o
>  LIB_OBJS += $(OUTPUT)util/stat.o
>  LIB_OBJS += $(OUTPUT)util/record.o
>  LIB_OBJS += $(OUTPUT)util/srcline.o
> +LIB_OBJS += $(OUTPUT)util/asprintf.o
>  LIB_OBJS += $(OUTPUT)util/data.o
>  LIB_OBJS += $(OUTPUT)util/tsc.o
>  LIB_OBJS += $(OUTPUT)util/cloexec.o
> diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
> index cd87a40..96bc166 100644
> --- a/tools/perf/builtin-report.c
> +++ b/tools/perf/builtin-report.c
> @@ -756,7 +756,8 @@ repeat:
>  		callchain_param.branch_callstack = 1;
>  		callchain_param.key = CCKEY_ADDRESS;
>  		symbol_conf.use_callchain = true;
> -		callchain_register_param(&callchain_param);
> +		if (callchain_register_param(&callchain_param) < 0)
> +			pr_err("Cannot register callchain parameters");

how is this hunk related to the patchset?

>  		if (sort_order == default_sort_order)
>  			sort_order = "srcline,symbol,dso";
>  		branch_mode = 0;
> diff --git a/tools/perf/util/asprintf.c b/tools/perf/util/asprintf.c
> new file mode 100644
> index 0000000..9aafaca
> --- /dev/null
> +++ b/tools/perf/util/asprintf.c
> @@ -0,0 +1,28 @@
> +/* Replacement for asprintf as it's buggy in older glibc versions */
> +#include <stdio.h>
> +#include <stdarg.h>
> +#include <stdlib.h>
> +#include <string.h>
> +
> +int vasprintf(char **str, const char *fmt, va_list ap)
> +{
> +	char buf[1024];

could you please make it work for generic buf len?

> +	int len = vsnprintf(buf, sizeof buf, fmt, ap);

WARNING: sizeof buf should be sizeof(buf)

> +
> +	*str = malloc(len + 1);
> +	if (!*str)
> +		return -1;
> +	strcpy(*str, buf);
> +	return len;
> +}

thanks,
jirka
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