[PATCH] perf util: Fix compression checks returning -1 as bool

[PATCH] perf util: Fix compression checks returning -1 as bool

[Yunseong Kim]

The lzma_is_compressed and gzip_is_compressed functions are declared
to return a "bool" type, but in case of an error (e.g., file open
failure), they incorrectly returned -1.

A bool type is a boolean value that is either true or false.
Returning -1 for a bool return type can lead to unexpected behavior
and may violate strict type-checking in some compilers.

Fix the return value to be false in error cases, ensuring the function
adheres to its declared return type improves for preventing potential
bugs related to type mismatch.

Fixes: 4b57fd44b61b ("perf tools: Add lzma_is_compressed function")
Fixes: 88c74dc76a30 ("perf tools: Add gzip_is_compressed function")
Signed-off-by: Yunseong Kim <ysk@kzalloc.com>
---
 tools/perf/util/lzma.c | 2 +-
 tools/perf/util/zlib.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/lzma.c b/tools/perf/util/lzma.c
index bbcd2ffcf4bd..c355757ed391 100644
--- a/tools/perf/util/lzma.c
+++ b/tools/perf/util/lzma.c
@@ -120,7 +120,7 @@ bool lzma_is_compressed(const char *input)
 	ssize_t rc;
 
 	if (fd < 0)
-		return -1;
+		return false;
 
 	rc = read(fd, buf, sizeof(buf));
 	close(fd);
diff --git a/tools/perf/util/zlib.c b/tools/perf/util/zlib.c
index 78d2297c1b67..1f7c06523059 100644
--- a/tools/perf/util/zlib.c
+++ b/tools/perf/util/zlib.c
@@ -88,7 +88,7 @@ bool gzip_is_compressed(const char *input)
 	ssize_t rc;
 
 	if (fd < 0)
-		return -1;
+		return false;
 
 	rc = read(fd, buf, sizeof(buf));
 	close(fd);
-- 
2.50.0

Re: [PATCH] perf util: Fix compression checks returning -1 as bool

[Ian Rogers]

On Fri, Aug 22, 2025 at 9:28 AM Yunseong Kim <ysk@kzalloc.com> wrote:
>
> The lzma_is_compressed and gzip_is_compressed functions are declared
> to return a "bool" type, but in case of an error (e.g., file open
> failure), they incorrectly returned -1.
>
> A bool type is a boolean value that is either true or false.
> Returning -1 for a bool return type can lead to unexpected behavior
> and may violate strict type-checking in some compilers.
>
> Fix the return value to be false in error cases, ensuring the function
> adheres to its declared return type improves for preventing potential
> bugs related to type mismatch.
>
> Fixes: 4b57fd44b61b ("perf tools: Add lzma_is_compressed function")
> Fixes: 88c74dc76a30 ("perf tools: Add gzip_is_compressed function")
> Signed-off-by: Yunseong Kim <ysk@kzalloc.com>

Reviewed-by: Ian Rogers <irogers@google.com>

Thanks,
Ian

> ---
>  tools/perf/util/lzma.c | 2 +-
>  tools/perf/util/zlib.c | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/util/lzma.c b/tools/perf/util/lzma.c
> index bbcd2ffcf4bd..c355757ed391 100644
> --- a/tools/perf/util/lzma.c
> +++ b/tools/perf/util/lzma.c
> @@ -120,7 +120,7 @@ bool lzma_is_compressed(const char *input)
>         ssize_t rc;
>
>         if (fd < 0)
> -               return -1;
> +               return false;
>
>         rc = read(fd, buf, sizeof(buf));
>         close(fd);
> diff --git a/tools/perf/util/zlib.c b/tools/perf/util/zlib.c
> index 78d2297c1b67..1f7c06523059 100644
> --- a/tools/perf/util/zlib.c
> +++ b/tools/perf/util/zlib.c
> @@ -88,7 +88,7 @@ bool gzip_is_compressed(const char *input)
>         ssize_t rc;
>
>         if (fd < 0)
> -               return -1;
> +               return false;
>
>         rc = read(fd, buf, sizeof(buf));
>         close(fd);
> --
> 2.50.0
>