| Message ID | 20240212-decompression-fixes-v1-9-06f92ad07985@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Load compressed modules with compression-less kmod | expand |
On Mon, Feb 12, 2024 at 05:23:10PM GMT, Emil Velikov via B4 Relay wrote: >From: Emil Velikov <emil.l.velikov@gmail.com> > >Since all the compression magic is always available now, we don't need >to loop at runtime nor use alloca - latter of which comes with a handful >of caveats. > >Simply throw in a few assert_cc(), which will trigger at build-time. given the small size, we actually never needed it and could have added the asserts. But this gets rid of more, with the loop going away, and I'm happy with it. Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com> thanks Lucas De Marchi
On Mon, Feb 12, 2024 at 05:23:10PM GMT, Emil Velikov via B4 Relay wrote: >From: Emil Velikov <emil.l.velikov@gmail.com> > >Since all the compression magic is always available now, we don't need >to loop at runtime nor use alloca - latter of which comes with a handful >of caveats. > >Simply throw in a few assert_cc(), which will trigger at build-time. > >Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com> >--- > libkmod/libkmod-file.c | 22 ++++++++-------------- > 1 file changed, 8 insertions(+), 14 deletions(-) > >diff --git a/libkmod/libkmod-file.c b/libkmod/libkmod-file.c >index b69f1ef..5b88d6c 100644 >--- a/libkmod/libkmod-file.c >+++ b/libkmod/libkmod-file.c >@@ -410,7 +410,6 @@ struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx, > { > struct kmod_file *file = calloc(1, sizeof(struct kmod_file)); > const struct comp_type *itr; >- size_t magic_size_max = 0; > int err = 0; > > if (file == NULL) >@@ -422,22 +421,17 @@ struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx, > goto error; > } > >- for (itr = comp_types; itr->load != NULL; itr++) { >- if (magic_size_max < itr->magic_size) >- magic_size_max = itr->magic_size; >- } >- >- if (magic_size_max > 0) { >- char *buf = alloca(magic_size_max + 1); >+ { >+ char buf[7]; > ssize_t sz; > >- if (buf == NULL) { >- err = -errno; >- goto error; >- } >- sz = read_str_safe(file->fd, buf, magic_size_max + 1); >+ assert_cc(sizeof(magic_zstd) < sizeof(buf)); >+ assert_cc(sizeof(magic_xz) < sizeof(buf)); >+ assert_cc(sizeof(magic_zlib) < sizeof(buf)); ../libkmod/libkmod-file.c: In function 'kmod_file_open': ../shared/macro.h:25:9: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement] 25 | _Static_assert((expr), #expr) | ^~~~~~~~~~~~~~ ../libkmod/libkmod-file.c:424:9: note: in expansion of macro 'assert_cc' 424 | assert_cc(sizeof(magic_zstd) < sizeof(buf)); | ^~~~~~~~~ So I'd go with this on top of this patch... I can squash it as needed when applying: |diff --git a/libkmod/libkmod-file.c b/libkmod/libkmod-file.c |index f162a10..8baf12d 100644 |--- a/libkmod/libkmod-file.c |+++ b/libkmod/libkmod-file.c |@@ -408,10 +408,15 @@ struct kmod_elf *kmod_file_get_elf(struct kmod_file *file) | struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx, | const char *filename) | { |- struct kmod_file *file = calloc(1, sizeof(struct kmod_file)); |+ struct kmod_file *file; | char buf[7]; | ssize_t sz; | |+ assert_cc(sizeof(magic_zstd) < sizeof(buf)); |+ assert_cc(sizeof(magic_xz) < sizeof(buf)); |+ assert_cc(sizeof(magic_zlib) < sizeof(buf)); |+ |+ file = calloc(1, sizeof(struct kmod_file)); | if (file == NULL) | return NULL; | |@@ -421,10 +426,6 @@ struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx, | return NULL; | } | |- assert_cc(sizeof(magic_zstd) < sizeof(buf)); |- assert_cc(sizeof(magic_xz) < sizeof(buf)); |- assert_cc(sizeof(magic_zlib) < sizeof(buf)); |- | sz = read_str_safe(file->fd, buf, sizeof(buf)); | lseek(file->fd, 0, SEEK_SET); | if (sz != (sizeof(buf) - 1)) { Lucas De Marchi
On Tue, 30 Apr 2024 at 18:39, Lucas De Marchi <lucas.demarchi@intel.com> wrote: > > On Mon, Feb 12, 2024 at 05:23:10PM GMT, Emil Velikov via B4 Relay wrote: > >From: Emil Velikov <emil.l.velikov@gmail.com> > > > >Since all the compression magic is always available now, we don't need > >to loop at runtime nor use alloca - latter of which comes with a handful > >of caveats. > > > >Simply throw in a few assert_cc(), which will trigger at build-time. > > > >Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com> > >--- > > libkmod/libkmod-file.c | 22 ++++++++-------------- > > 1 file changed, 8 insertions(+), 14 deletions(-) > > > >diff --git a/libkmod/libkmod-file.c b/libkmod/libkmod-file.c > >index b69f1ef..5b88d6c 100644 > >--- a/libkmod/libkmod-file.c > >+++ b/libkmod/libkmod-file.c > >@@ -410,7 +410,6 @@ struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx, > > { > > struct kmod_file *file = calloc(1, sizeof(struct kmod_file)); > > const struct comp_type *itr; > >- size_t magic_size_max = 0; > > int err = 0; > > > > if (file == NULL) > >@@ -422,22 +421,17 @@ struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx, > > goto error; > > } > > > >- for (itr = comp_types; itr->load != NULL; itr++) { > >- if (magic_size_max < itr->magic_size) > >- magic_size_max = itr->magic_size; > >- } > >- > >- if (magic_size_max > 0) { > >- char *buf = alloca(magic_size_max + 1); > >+ { > >+ char buf[7]; > > ssize_t sz; > > > >- if (buf == NULL) { > >- err = -errno; > >- goto error; > >- } > >- sz = read_str_safe(file->fd, buf, magic_size_max + 1); > >+ assert_cc(sizeof(magic_zstd) < sizeof(buf)); > >+ assert_cc(sizeof(magic_xz) < sizeof(buf)); > >+ assert_cc(sizeof(magic_zlib) < sizeof(buf)); > > ../libkmod/libkmod-file.c: In function 'kmod_file_open': > ../shared/macro.h:25:9: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement] Is there a particular use-case for explicitly forcing C90? The configure.ac contains `AC_PROG_CC_C99`, which seems reasonable IMHO. Plus the autogen.sh goes a step further with `-std=gnu11` Thanks Emil
On Tue, Apr 30, 2024 at 06:54:00PM GMT, Emil Velikov wrote: >On Tue, 30 Apr 2024 at 18:39, Lucas De Marchi <lucas.demarchi@intel.com> wrote: >> >> On Mon, Feb 12, 2024 at 05:23:10PM GMT, Emil Velikov via B4 Relay wrote: >> >From: Emil Velikov <emil.l.velikov@gmail.com> >> > >> >Since all the compression magic is always available now, we don't need >> >to loop at runtime nor use alloca - latter of which comes with a handful >> >of caveats. >> > >> >Simply throw in a few assert_cc(), which will trigger at build-time. >> > >> >Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com> >> >--- >> > libkmod/libkmod-file.c | 22 ++++++++-------------- >> > 1 file changed, 8 insertions(+), 14 deletions(-) >> > >> >diff --git a/libkmod/libkmod-file.c b/libkmod/libkmod-file.c >> >index b69f1ef..5b88d6c 100644 >> >--- a/libkmod/libkmod-file.c >> >+++ b/libkmod/libkmod-file.c >> >@@ -410,7 +410,6 @@ struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx, >> > { >> > struct kmod_file *file = calloc(1, sizeof(struct kmod_file)); >> > const struct comp_type *itr; >> >- size_t magic_size_max = 0; >> > int err = 0; >> > >> > if (file == NULL) >> >@@ -422,22 +421,17 @@ struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx, >> > goto error; >> > } >> > >> >- for (itr = comp_types; itr->load != NULL; itr++) { >> >- if (magic_size_max < itr->magic_size) >> >- magic_size_max = itr->magic_size; >> >- } >> >- >> >- if (magic_size_max > 0) { >> >- char *buf = alloca(magic_size_max + 1); >> >+ { >> >+ char buf[7]; >> > ssize_t sz; >> > >> >- if (buf == NULL) { >> >- err = -errno; >> >- goto error; >> >- } >> >- sz = read_str_safe(file->fd, buf, magic_size_max + 1); >> >+ assert_cc(sizeof(magic_zstd) < sizeof(buf)); >> >+ assert_cc(sizeof(magic_xz) < sizeof(buf)); >> >+ assert_cc(sizeof(magic_zlib) < sizeof(buf)); >> >> ../libkmod/libkmod-file.c: In function 'kmod_file_open': >> ../shared/macro.h:25:9: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement] > >Is there a particular use-case for explicitly forcing C90? not forcing C90, but forcing -Wdeclaration-after-statement as per flag passed in configure.ac. I think the message given by gcc is misleading here. Lucas De Marchi > >The configure.ac contains `AC_PROG_CC_C99`, which seems reasonable >IMHO. Plus the autogen.sh goes a step further with `-std=gnu11` > >Thanks >Emil
On Tue, 30 Apr 2024 at 19:18, Lucas De Marchi <lucas.demarchi@intel.com> wrote: > > On Tue, Apr 30, 2024 at 06:54:00PM GMT, Emil Velikov wrote: > >On Tue, 30 Apr 2024 at 18:39, Lucas De Marchi <lucas.demarchi@intel.com> wrote: > >> > >> On Mon, Feb 12, 2024 at 05:23:10PM GMT, Emil Velikov via B4 Relay wrote: > >> >From: Emil Velikov <emil.l.velikov@gmail.com> > >> > > >> >Since all the compression magic is always available now, we don't need > >> >to loop at runtime nor use alloca - latter of which comes with a handful > >> >of caveats. > >> > > >> >Simply throw in a few assert_cc(), which will trigger at build-time. > >> > > >> >Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com> > >> >--- > >> > libkmod/libkmod-file.c | 22 ++++++++-------------- > >> > 1 file changed, 8 insertions(+), 14 deletions(-) > >> > > >> >diff --git a/libkmod/libkmod-file.c b/libkmod/libkmod-file.c > >> >index b69f1ef..5b88d6c 100644 > >> >--- a/libkmod/libkmod-file.c > >> >+++ b/libkmod/libkmod-file.c > >> >@@ -410,7 +410,6 @@ struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx, > >> > { > >> > struct kmod_file *file = calloc(1, sizeof(struct kmod_file)); > >> > const struct comp_type *itr; > >> >- size_t magic_size_max = 0; > >> > int err = 0; > >> > > >> > if (file == NULL) > >> >@@ -422,22 +421,17 @@ struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx, > >> > goto error; > >> > } > >> > > >> >- for (itr = comp_types; itr->load != NULL; itr++) { > >> >- if (magic_size_max < itr->magic_size) > >> >- magic_size_max = itr->magic_size; > >> >- } > >> >- > >> >- if (magic_size_max > 0) { > >> >- char *buf = alloca(magic_size_max + 1); > >> >+ { > >> >+ char buf[7]; > >> > ssize_t sz; > >> > > >> >- if (buf == NULL) { > >> >- err = -errno; > >> >- goto error; > >> >- } > >> >- sz = read_str_safe(file->fd, buf, magic_size_max + 1); > >> >+ assert_cc(sizeof(magic_zstd) < sizeof(buf)); > >> >+ assert_cc(sizeof(magic_xz) < sizeof(buf)); > >> >+ assert_cc(sizeof(magic_zlib) < sizeof(buf)); > >> > >> ../libkmod/libkmod-file.c: In function 'kmod_file_open': > >> ../shared/macro.h:25:9: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement] > > > >Is there a particular use-case for explicitly forcing C90? > > not forcing C90, but forcing -Wdeclaration-after-statement as per > flag passed in configure.ac. I think the message given by gcc is > misleading here. > Indeed thanks. Seems like I should add `export CFLAGS+=-Werror" to my dev box. -Emil
On Tue, Apr 30, 2024 at 07:27:00PM GMT, Emil Velikov wrote: >On Tue, 30 Apr 2024 at 19:18, Lucas De Marchi <lucas.demarchi@intel.com> wrote: >> >> On Tue, Apr 30, 2024 at 06:54:00PM GMT, Emil Velikov wrote: >> >On Tue, 30 Apr 2024 at 18:39, Lucas De Marchi <lucas.demarchi@intel.com> wrote: >> >> >> >> On Mon, Feb 12, 2024 at 05:23:10PM GMT, Emil Velikov via B4 Relay wrote: >> >> >From: Emil Velikov <emil.l.velikov@gmail.com> >> >> > >> >> >Since all the compression magic is always available now, we don't need >> >> >to loop at runtime nor use alloca - latter of which comes with a handful >> >> >of caveats. >> >> > >> >> >Simply throw in a few assert_cc(), which will trigger at build-time. >> >> > >> >> >Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com> >> >> >--- >> >> > libkmod/libkmod-file.c | 22 ++++++++-------------- >> >> > 1 file changed, 8 insertions(+), 14 deletions(-) >> >> > >> >> >diff --git a/libkmod/libkmod-file.c b/libkmod/libkmod-file.c >> >> >index b69f1ef..5b88d6c 100644 >> >> >--- a/libkmod/libkmod-file.c >> >> >+++ b/libkmod/libkmod-file.c >> >> >@@ -410,7 +410,6 @@ struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx, >> >> > { >> >> > struct kmod_file *file = calloc(1, sizeof(struct kmod_file)); >> >> > const struct comp_type *itr; >> >> >- size_t magic_size_max = 0; >> >> > int err = 0; >> >> > >> >> > if (file == NULL) >> >> >@@ -422,22 +421,17 @@ struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx, >> >> > goto error; >> >> > } >> >> > >> >> >- for (itr = comp_types; itr->load != NULL; itr++) { >> >> >- if (magic_size_max < itr->magic_size) >> >> >- magic_size_max = itr->magic_size; >> >> >- } >> >> >- >> >> >- if (magic_size_max > 0) { >> >> >- char *buf = alloca(magic_size_max + 1); >> >> >+ { >> >> >+ char buf[7]; >> >> > ssize_t sz; >> >> > >> >> >- if (buf == NULL) { >> >> >- err = -errno; >> >> >- goto error; >> >> >- } >> >> >- sz = read_str_safe(file->fd, buf, magic_size_max + 1); >> >> >+ assert_cc(sizeof(magic_zstd) < sizeof(buf)); >> >> >+ assert_cc(sizeof(magic_xz) < sizeof(buf)); >> >> >+ assert_cc(sizeof(magic_zlib) < sizeof(buf)); >> >> >> >> ../libkmod/libkmod-file.c: In function 'kmod_file_open': >> >> ../shared/macro.h:25:9: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement] >> > >> >Is there a particular use-case for explicitly forcing C90? >> >> not forcing C90, but forcing -Wdeclaration-after-statement as per >> flag passed in configure.ac. I think the message given by gcc is >> misleading here. >> > >Indeed thanks. Seems like I should add `export CFLAGS+=-Werror" to my dev box. so, are you ok that I just squash this? Lucas De Marchi > >-Emil
On Tue, 30 Apr 2024 at 19:43, Lucas De Marchi <lucas.demarchi@intel.com> wrote: > > On Tue, Apr 30, 2024 at 07:27:00PM GMT, Emil Velikov wrote: > >On Tue, 30 Apr 2024 at 19:18, Lucas De Marchi <lucas.demarchi@intel.com> wrote: > >> > >> On Tue, Apr 30, 2024 at 06:54:00PM GMT, Emil Velikov wrote: > >> >On Tue, 30 Apr 2024 at 18:39, Lucas De Marchi <lucas.demarchi@intel.com> wrote: > >> >> > >> >> On Mon, Feb 12, 2024 at 05:23:10PM GMT, Emil Velikov via B4 Relay wrote: > >> >> >From: Emil Velikov <emil.l.velikov@gmail.com> > >> >> > > >> >> >Since all the compression magic is always available now, we don't need > >> >> >to loop at runtime nor use alloca - latter of which comes with a handful > >> >> >of caveats. > >> >> > > >> >> >Simply throw in a few assert_cc(), which will trigger at build-time. > >> >> > > >> >> >Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com> > >> >> >--- > >> >> > libkmod/libkmod-file.c | 22 ++++++++-------------- > >> >> > 1 file changed, 8 insertions(+), 14 deletions(-) > >> >> > > >> >> >diff --git a/libkmod/libkmod-file.c b/libkmod/libkmod-file.c > >> >> >index b69f1ef..5b88d6c 100644 > >> >> >--- a/libkmod/libkmod-file.c > >> >> >+++ b/libkmod/libkmod-file.c > >> >> >@@ -410,7 +410,6 @@ struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx, > >> >> > { > >> >> > struct kmod_file *file = calloc(1, sizeof(struct kmod_file)); > >> >> > const struct comp_type *itr; > >> >> >- size_t magic_size_max = 0; > >> >> > int err = 0; > >> >> > > >> >> > if (file == NULL) > >> >> >@@ -422,22 +421,17 @@ struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx, > >> >> > goto error; > >> >> > } > >> >> > > >> >> >- for (itr = comp_types; itr->load != NULL; itr++) { > >> >> >- if (magic_size_max < itr->magic_size) > >> >> >- magic_size_max = itr->magic_size; > >> >> >- } > >> >> >- > >> >> >- if (magic_size_max > 0) { > >> >> >- char *buf = alloca(magic_size_max + 1); > >> >> >+ { > >> >> >+ char buf[7]; > >> >> > ssize_t sz; > >> >> > > >> >> >- if (buf == NULL) { > >> >> >- err = -errno; > >> >> >- goto error; > >> >> >- } > >> >> >- sz = read_str_safe(file->fd, buf, magic_size_max + 1); > >> >> >+ assert_cc(sizeof(magic_zstd) < sizeof(buf)); > >> >> >+ assert_cc(sizeof(magic_xz) < sizeof(buf)); > >> >> >+ assert_cc(sizeof(magic_zlib) < sizeof(buf)); > >> >> > >> >> ../libkmod/libkmod-file.c: In function 'kmod_file_open': > >> >> ../shared/macro.h:25:9: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement] > >> > > >> >Is there a particular use-case for explicitly forcing C90? > >> > >> not forcing C90, but forcing -Wdeclaration-after-statement as per > >> flag passed in configure.ac. I think the message given by gcc is > >> misleading here. > >> > > > >Indeed thanks. Seems like I should add `export CFLAGS+=-Werror" to my dev box. > > so, are you ok that I just squash this? > Yes, of course. -Emil
On Tue, Apr 30, 2024 at 07:47:46PM GMT, Emil Velikov wrote: >On Tue, 30 Apr 2024 at 19:43, Lucas De Marchi <lucas.demarchi@intel.com> wrote: >> >> On Tue, Apr 30, 2024 at 07:27:00PM GMT, Emil Velikov wrote: >> >On Tue, 30 Apr 2024 at 19:18, Lucas De Marchi <lucas.demarchi@intel.com> wrote: >> >> >> >> On Tue, Apr 30, 2024 at 06:54:00PM GMT, Emil Velikov wrote: >> >> >On Tue, 30 Apr 2024 at 18:39, Lucas De Marchi <lucas.demarchi@intel.com> wrote: >> >> >> >> >> >> On Mon, Feb 12, 2024 at 05:23:10PM GMT, Emil Velikov via B4 Relay wrote: >> >> >> >From: Emil Velikov <emil.l.velikov@gmail.com> >> >> >> > >> >> >> >Since all the compression magic is always available now, we don't need >> >> >> >to loop at runtime nor use alloca - latter of which comes with a handful >> >> >> >of caveats. >> >> >> > >> >> >> >Simply throw in a few assert_cc(), which will trigger at build-time. >> >> >> > >> >> >> >Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com> >> >> >> >--- >> >> >> > libkmod/libkmod-file.c | 22 ++++++++-------------- >> >> >> > 1 file changed, 8 insertions(+), 14 deletions(-) >> >> >> > >> >> >> >diff --git a/libkmod/libkmod-file.c b/libkmod/libkmod-file.c >> >> >> >index b69f1ef..5b88d6c 100644 >> >> >> >--- a/libkmod/libkmod-file.c >> >> >> >+++ b/libkmod/libkmod-file.c >> >> >> >@@ -410,7 +410,6 @@ struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx, >> >> >> > { >> >> >> > struct kmod_file *file = calloc(1, sizeof(struct kmod_file)); >> >> >> > const struct comp_type *itr; >> >> >> >- size_t magic_size_max = 0; >> >> >> > int err = 0; >> >> >> > >> >> >> > if (file == NULL) >> >> >> >@@ -422,22 +421,17 @@ struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx, >> >> >> > goto error; >> >> >> > } >> >> >> > >> >> >> >- for (itr = comp_types; itr->load != NULL; itr++) { >> >> >> >- if (magic_size_max < itr->magic_size) >> >> >> >- magic_size_max = itr->magic_size; >> >> >> >- } >> >> >> >- >> >> >> >- if (magic_size_max > 0) { >> >> >> >- char *buf = alloca(magic_size_max + 1); >> >> >> >+ { >> >> >> >+ char buf[7]; >> >> >> > ssize_t sz; >> >> >> > >> >> >> >- if (buf == NULL) { >> >> >> >- err = -errno; >> >> >> >- goto error; >> >> >> >- } >> >> >> >- sz = read_str_safe(file->fd, buf, magic_size_max + 1); >> >> >> >+ assert_cc(sizeof(magic_zstd) < sizeof(buf)); >> >> >> >+ assert_cc(sizeof(magic_xz) < sizeof(buf)); >> >> >> >+ assert_cc(sizeof(magic_zlib) < sizeof(buf)); >> >> >> >> >> >> ../libkmod/libkmod-file.c: In function 'kmod_file_open': >> >> >> ../shared/macro.h:25:9: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement] >> >> > >> >> >Is there a particular use-case for explicitly forcing C90? >> >> >> >> not forcing C90, but forcing -Wdeclaration-after-statement as per >> >> flag passed in configure.ac. I think the message given by gcc is >> >> misleading here. >> >> >> > >> >Indeed thanks. Seems like I should add `export CFLAGS+=-Werror" to my dev box. >> >> so, are you ok that I just squash this? >> > >Yes, of course. thanks, pushed everything except the last patch. Lucas De Marchi > >-Emil
diff --git a/libkmod/libkmod-file.c b/libkmod/libkmod-file.c index b69f1ef..5b88d6c 100644 --- a/libkmod/libkmod-file.c +++ b/libkmod/libkmod-file.c @@ -410,7 +410,6 @@ struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx, { struct kmod_file *file = calloc(1, sizeof(struct kmod_file)); const struct comp_type *itr; - size_t magic_size_max = 0; int err = 0; if (file == NULL) @@ -422,22 +421,17 @@ struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx, goto error; } - for (itr = comp_types; itr->load != NULL; itr++) { - if (magic_size_max < itr->magic_size) - magic_size_max = itr->magic_size; - } - - if (magic_size_max > 0) { - char *buf = alloca(magic_size_max + 1); + { + char buf[7]; ssize_t sz; - if (buf == NULL) { - err = -errno; - goto error; - } - sz = read_str_safe(file->fd, buf, magic_size_max + 1); + assert_cc(sizeof(magic_zstd) < sizeof(buf)); + assert_cc(sizeof(magic_xz) < sizeof(buf)); + assert_cc(sizeof(magic_zlib) < sizeof(buf)); + + sz = read_str_safe(file->fd, buf, sizeof(buf)); lseek(file->fd, 0, SEEK_SET); - if (sz != (ssize_t)magic_size_max) { + if (sz != (sizeof(buf) - 1)) { if (sz < 0) err = sz; else