https://gcc.gnu.org/g:44058b847145166715f15e49fa8854f30e852f24
commit r15-3600-g44058b847145166715f15e49fa8854f30e852f24
Author: Jakub Jelinek <ja...@redhat.com>
Date: Thu Sep 12 11:34:06 2024 +0200
libcpp: Add support for gnu::offset #embed/__has_embed parameter
The following patch adds on top of the just posted #embed patch
a first extension, gnu::offset which allows to seek in the data
file (for seekable files, otherwise read and throw away).
I think this is useful e.g. when some binary data start with
some well known header which shouldn't be included in the data etc.
2024-09-12 Jakub Jelinek <ja...@redhat.com>
libcpp/
* internal.h (struct cpp_embed_params): Add offset member.
* directives.cc (EMBED_PARAMS): Add gnu::offset entry.
(enum embed_param_kind): Add NUM_EMBED_STD_PARAMS.
(_cpp_parse_embed_params): Use NUM_EMBED_STD_PARAMS rather than
NUM_EMBED_PARAMS when parsing standard parameters. Parse
gnu::offset
parameter.
* files.cc (struct _cpp_file): Add offset member.
(_cpp_stack_embed): Handle params->offset.
gcc/
* doc/cpp.texi (Binary Resource Inclusion): Document gnu::offset
#embed parameter.
gcc/testsuite/
* c-c++-common/cpp/embed-15.c: New test.
* c-c++-common/cpp/embed-16.c: New test.
* gcc.dg/cpp/embed-5.c: New test.
Diff:
---
gcc/doc/cpp.texi | 8 ++-
gcc/testsuite/c-c++-common/cpp/embed-15.c | 88 ++++++++++++++++++++++++++++
gcc/testsuite/c-c++-common/cpp/embed-16.c | 31 ++++++++++
gcc/testsuite/gcc.dg/cpp/embed-5.c | 4 ++
libcpp/directives.cc | 40 ++++++++++---
libcpp/files.cc | 95 ++++++++++++++++++++++++++-----
libcpp/internal.h | 2 +-
7 files changed, 244 insertions(+), 24 deletions(-)
diff --git a/gcc/doc/cpp.texi b/gcc/doc/cpp.texi
index 032b095602d5..612d97e16df8 100644
--- a/gcc/doc/cpp.texi
+++ b/gcc/doc/cpp.texi
@@ -3966,8 +3966,8 @@ treated the same), followed by parameter argument in
parentheses, like
with currently supported standard parameters @code{limit}, @code{prefix},
@code{suffix} and @code{if_empty}, or implementation defined parameters
specified by a unique vendor prefix followed by @code{::} followed by
-name of the parameter. GCC will use the @code{gnu} prefix but currently
-doesn't support any extensions.
+name of the parameter. GCC uses the @code{gnu} prefix for vendor
+parameters and currently supports the @code{gnu::offset} parameter.
The @code{limit} parameter argument is a constant expression which
specifies the maximum number of bytes included by the directive,
@@ -3977,6 +3977,10 @@ that sequence is not empty and @code{if_empty} argument
is balanced token
sequence which is used as expansion for @code{#embed} directive if the
resource is empty.
+The @code{gnu::offset} parameter argument is a constant expression
+which specifies how many bytes to skip from the start of the resource.
+@code{limit} is then counted from that position.
+
The @code{#embed} directive is not supported in the Traditional Mode
(@pxref{Traditional Mode}).
diff --git a/gcc/testsuite/c-c++-common/cpp/embed-15.c
b/gcc/testsuite/c-c++-common/cpp/embed-15.c
new file mode 100644
index 000000000000..c12aeb31db53
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/cpp/embed-15.c
@@ -0,0 +1,88 @@
+/* { dg-do run } */
+/* { dg-options "--embed-dir=${srcdir}/c-c++-common/cpp/embed-dir" } */
+/* { dg-additional-options "-std=gnu99" { target c } } */
+
+#if __has_embed (__FILE__ gnu::offset (4 + FOOBAR) limit (3)) !=
__STDC_EMBED_FOUND__
+#error "__has_embed fail"
+#endif
+
+#embed <magna-carta.txt> limit(1) gnu::offset (0) prefix(int a = ) suffix (;)
+#embed <magna-carta.txt> limit(1) __gnu__::offset (1 * 1) prefix(int b = )
suffix (;)
+#embed <magna-carta.txt> limit(1) gnu::__offset__ (1 + 1) prefix(int c = )
suffix (;)
+#embed <magna-carta.txt> __limit__(1) __gnu__::__offset__ (1 + (1 \
+ + 1)) __prefix__(int d = ) __suffix__ (;)
+const unsigned char e[] = {
+ #embed <magna-carta.txt> limit(5) gnu::offset (999)
+};
+const unsigned char f[] = {
+ #embed <magna-carta.txt> limit(7) gnu::offset (998)
+};
+const unsigned char g[] = {
+ #embed <magna-carta.txt> limit(8) gnu::offset (998)
+};
+const unsigned char h[] = {
+ #embed <magna-carta.txt> limit(8) gnu::offset (997)
+};
+const unsigned char i[] = {
+ #embed <magna-carta.txt> limit(9) gnu::offset (997)
+};
+const unsigned char j[] = {
+ #embed <magna-carta.txt> limit(30) gnu::offset (990)
+};
+const unsigned char k[] = {
+ #embed <magna-carta.txt> limit(26) gnu::offset (992)
+};
+const unsigned char l[] = {
+ #embed <magna-carta.txt>
+};
+const unsigned char m[] = {
+ #embed <magna-carta.txt> __limit__ (1000) __gnu__::__offset__ (32)
+};
+#if __has_embed (<magna-carta.txt> limit(5) gnu::offset (999)) !=
__STDC_EMBED_FOUND__ \
+ || __has_embed (<magna-carta.txt> limit(5) gnu::offset (999)) !=
__STDC_EMBED_FOUND__ \
+ || __has_embed (<magna-carta.txt> limit(7) gnu::offset (998)) !=
__STDC_EMBED_FOUND__ \
+ || __has_embed (<magna-carta.txt> limit(8) gnu::offset (998)) !=
__STDC_EMBED_FOUND__ \
+ || __has_embed (<magna-carta.txt> limit(8) gnu::offset (997)) !=
__STDC_EMBED_FOUND__ \
+ || __has_embed (<magna-carta.txt> limit(9) gnu::offset (997)) !=
__STDC_EMBED_FOUND__ \
+ || __has_embed (<magna-carta.txt> limit(30) gnu::offset (990)) !=
__STDC_EMBED_FOUND__ \
+ || __has_embed (<magna-carta.txt> limit(26) gnu::offset (992)) !=
__STDC_EMBED_FOUND__ \
+ || __has_embed (<magna-carta.txt>) != __STDC_EMBED_FOUND__ \
+ || __has_embed (<magna-carta.txt> limit(26) gnu::offset (992)) !=
__STDC_EMBED_FOUND__
+#error "__has_embed fail"
+#endif
+
+#ifdef __cplusplus
+#define C "C"
+#else
+#define C
+#endif
+extern C void abort (void);
+extern C int memcmp (const void *, const void *, __SIZE_TYPE__);
+
+int
+main ()
+{
+ if (a != 'H' || b != 'e' || c != 'n' || d != 'r')
+ abort ();
+ if (sizeof (e) != 5
+ || sizeof (f) != 7
+ || sizeof (g) != 8
+ || sizeof (h) != 8
+ || sizeof (i) != 9
+ || sizeof (j) != 30
+ || sizeof (k) != 26
+ || sizeof (l) < 1032
+ || sizeof (m) != 1000)
+ abort ();
+ if (memcmp (e, l + 999, 5)
+ || memcmp (f, l + 998, 7)
+ || memcmp (g, l + 998, 8)
+ || memcmp (h, l + 997, 8)
+ || memcmp (i, l + 997, 9)
+ || memcmp (j, l + 990, 30)
+ || memcmp (k, l + 992, 26)
+ || memcmp (m, l + 32, 1000))
+ abort ();
+ if (l[0] != 'H' || l[1] != 'e' || l[2] != 'n' || l[3] != 'r')
+ abort ();
+}
diff --git a/gcc/testsuite/c-c++-common/cpp/embed-16.c
b/gcc/testsuite/c-c++-common/cpp/embed-16.c
new file mode 100644
index 000000000000..a3d1a6d10287
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/cpp/embed-16.c
@@ -0,0 +1,31 @@
+/* { dg-do preprocess } */
+/* { dg-options "" } */
+
+#embed __FILE__ gnu::offset(1) gnu::offset(1) /* { dg-error "duplicate embed
parameter 'gnu::offset'" } */
+#embed __FILE__ gnu::offset prefix() suffix() /* { dg-error "expected '\\\('"
} */
+#embed __FILE__ gnu::offset (1 / 0) /* { dg-error "division by zero in #embed"
} */
+#embed __FILE__ __gnu__::__offset__ (+ + +) /* { dg-error "operator '\\\+' has
no right operand" } */
+#define FOO 1
+#embed __FILE__ gnu::offset(0 + defined(FOO)) /* { dg-error "'defined' in
#embed parameter" } */
+#embed __FILE__ gnu::offset (-1) /* { dg-error "negative embed parameter
operand" } */
+#embed __FILE__ gnu::offset (-42) /* { dg-error "negative embed parameter
operand" } */
+#embed __FILE__ gnu::offset (-9223372036854775807 - 1) /* { dg-error "negative
embed parameter operand" } */
+#embed __FILE__ gnu::offset (18446744073709551615ULL) /* { dg-error "too large
'gnu::offset' argument" } */
+#if 1 + __has_embed (__FILE__ gnu::offset(1) __gnu__::__offset__(1)) /* {
dg-error "duplicate embed parameter 'gnu::offset'" } */
+#endif
+#if 1 + __has_embed (__FILE__ __gnu__::__offset__ prefix() suffix()) /* {
dg-error "expected '\\\('" } */
+#endif
+#if 1 + __has_embed (__FILE__ gnu::offset(1/0)) /* { dg-error "division by
zero in #embed" } */
+#endif
+#if 1 + __has_embed (__FILE__ gnu::offset(+ + +)) /* { dg-error "operator
'\\\+' has no right operand" } */
+#endif
+#if 1 + __has_embed (__FILE__ gnu::offset(0 + defined(FOO))) /* { dg-error
"'defined' in #embed parameter" } */
+#endif
+#if 1 + __has_embed (__FILE__ gnu::offset (-1)) /* { dg-error "negative embed
parameter operand" } */
+#endif
+#if 1 + __has_embed (__FILE__ gnu::offset (-42)) /* { dg-error "negative embed
parameter operand" } */
+#endif
+#if 1 + __has_embed (__FILE__ gnu::offset (-9223372036854775807 - 1)) /* {
dg-error "negative embed parameter operand" } */
+#endif
+#if 1 + __has_embed (__FILE__ gnu::offset (18446744073709551615ULL)) /* {
dg-error "too large 'gnu::offset' argument" } */
+#endif
diff --git a/gcc/testsuite/gcc.dg/cpp/embed-5.c
b/gcc/testsuite/gcc.dg/cpp/embed-5.c
new file mode 100644
index 000000000000..64209144841a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/cpp/embed-5.c
@@ -0,0 +1,4 @@
+/* { dg-do run } */
+/* { dg-options "-std=c23 -pedantic-errors
--embed-dir=${srcdir}/c-c++-common/cpp/embed-dir" } */
+
+#include "../../c-c++-common/cpp/embed-15.c"
diff --git a/libcpp/directives.cc b/libcpp/directives.cc
index 4aac519ff40c..f8d98980f2e7 100644
--- a/libcpp/directives.cc
+++ b/libcpp/directives.cc
@@ -1014,13 +1014,15 @@ skip_balanced_token_seq (cpp_reader *pfile, cpp_ttype
end,
EMBED_PARAM (LIMIT, "limit") \
EMBED_PARAM (PREFIX, "prefix") \
EMBED_PARAM (SUFFIX, "suffix") \
- EMBED_PARAM (IF_EMPTY, "if_empty")
+ EMBED_PARAM (IF_EMPTY, "if_empty") \
+ EMBED_PARAM (GNU_OFFSET, "offset")
enum embed_param_kind {
#define EMBED_PARAM(c, s) EMBED_PARAM_##c,
EMBED_PARAMS
#undef EMBED_PARAM
- NUM_EMBED_PARAMS
+ NUM_EMBED_PARAMS,
+ NUM_EMBED_STD_PARAMS = EMBED_PARAM_IF_EMPTY + 1
};
static struct { int len; const char *name; } embed_params[NUM_EMBED_PARAMS] = {
@@ -1120,7 +1122,18 @@ _cpp_parse_embed_params (cpp_reader *pfile, struct
cpp_embed_params *params)
size_t param_kind = -1;
if (param_prefix == NULL)
{
- for (size_t i = 0; i < NUM_EMBED_PARAMS; ++i)
+ for (size_t i = 0; i < NUM_EMBED_STD_PARAMS; ++i)
+ if (param_name_len == embed_params[i].len
+ && memcmp (param_name, embed_params[i].name,
+ param_name_len) == 0)
+ {
+ param_kind = i;
+ break;
+ }
+ }
+ else if (param_prefix_len == 3 && memcmp (param_prefix, "gnu", 3) == 0)
+ {
+ for (size_t i = NUM_EMBED_STD_PARAMS; i < NUM_EMBED_PARAMS; ++i)
if (param_name_len == embed_params[i].len
&& memcmp (param_name, embed_params[i].name,
param_name_len) == 0)
@@ -1157,12 +1170,23 @@ _cpp_parse_embed_params (cpp_reader *pfile, struct
cpp_embed_params *params)
if (param_kind != (size_t) -1 && token->type != CPP_OPEN_PAREN)
cpp_error_with_line (pfile, CPP_DL_ERROR, loc, 0,
"expected '('");
- else if (param_kind == EMBED_PARAM_LIMIT)
+ else if (param_kind == EMBED_PARAM_LIMIT
+ || param_kind == EMBED_PARAM_GNU_OFFSET)
{
- if (params->has_embed && pfile->op_stack == NULL)
- _cpp_expand_op_stack (pfile);
- params->limit = _cpp_parse_expr (pfile, "#embed", token);
- token = _cpp_get_token_no_padding (pfile);
+ if (params->has_embed && pfile->op_stack == NULL)
+ _cpp_expand_op_stack (pfile);
+ cpp_num_part res = _cpp_parse_expr (pfile, "#embed", token);
+ if (param_kind == EMBED_PARAM_LIMIT)
+ params->limit = res;
+ else
+ {
+ if (res > INTTYPE_MAXIMUM (off_t))
+ cpp_error_with_line (pfile, CPP_DL_ERROR, loc, 0,
+ "too large 'gnu::offset' argument");
+ else
+ params->offset = res;
+ }
+ token = _cpp_get_token_no_padding (pfile);
}
else if (token->type == CPP_OPEN_PAREN)
{
diff --git a/libcpp/files.cc b/libcpp/files.cc
index 52b1850f2263..9d64bff657b4 100644
--- a/libcpp/files.cc
+++ b/libcpp/files.cc
@@ -90,6 +90,9 @@ struct _cpp_file
/* Size for #embed, perhaps smaller than st.st_size. */
size_t limit;
+ /* Offset for #embed. */
+ off_t offset;
+
/* File descriptor. Invalid if -1, otherwise open. */
int fd;
@@ -1242,8 +1245,11 @@ _cpp_stack_embed (cpp_reader *pfile, const char *fname,
bool angle,
_cpp_file *orig_file = file;
if (file->buffer_valid
&& (!S_ISREG (file->st.st_mode)
- || (file->limit < file->st.st_size + (size_t) 0
- && file->limit < params->limit)))
+ || file->offset + (cpp_num_part) 0 > params->offset
+ || (file->limit < file->st.st_size - file->offset + (size_t) 0
+ && (params->offset - file->offset > (cpp_num_part) file->limit
+ || file->limit - (params->offset
+ - file->offset) < params->limit))))
{
bool found = false;
if (S_ISREG (file->st.st_mode))
@@ -1256,8 +1262,13 @@ _cpp_stack_embed (cpp_reader *pfile, const char *fname,
bool angle,
&& strcmp (file->path, file->next_file->path) == 0)
{
file = file->next_file;
- if (file->limit >= file->st.st_size + (size_t) 0
- || file->limit >= params->limit)
+ if (file->offset + (cpp_num_part) 0 <= params->offset
+ && (file->limit >= (file->st.st_size - file->offset
+ + (size_t) 0)
+ || (params->offset
+ - file->offset <= (cpp_num_part) file->limit
+ && file->limit - (params->offset
+ - file->offset) >= params->limit)))
{
found = true;
break;
@@ -1313,8 +1324,10 @@ _cpp_stack_embed (cpp_reader *pfile, const char *fname,
bool angle,
if (regular)
{
cpp_num_part limit;
- if (file->st.st_size + (cpp_num_part) 0 < params->limit)
- limit = file->st.st_size;
+ if (file->st.st_size + (cpp_num_part) 0 < params->offset)
+ limit = 0;
+ else if (file->st.st_size - params->offset < params->limit)
+ limit = file->st.st_size - params->offset;
else
limit = params->limit;
if (params->has_embed)
@@ -1325,6 +1338,14 @@ _cpp_stack_embed (cpp_reader *pfile, const char *fname,
bool angle,
"%s is too large", file->path);
goto fail;
}
+ if (lseek (file->fd, params->offset, SEEK_CUR)
+ != (off_t) params->offset)
+ {
+ cpp_errno_filename (pfile, CPP_DL_ERROR, file->path,
+ params->loc);
+ goto fail;
+ }
+ file->offset = params->offset;
file->limit = limit;
size = limit;
}
@@ -1337,6 +1358,38 @@ _cpp_stack_embed (cpp_reader *pfile, const char *fname,
bool angle,
buf = XNEWVEC (uchar, size ? size : 1);
total = 0;
+ if (!regular && params->offset)
+ {
+ uchar *buf2 = buf;
+ ssize_t size2 = size;
+ cpp_num_part total2 = params->offset;
+
+ if (params->offset > 8 * 1024 && size < 8 * 1024)
+ {
+ size2 = 32 * 1024;
+ buf2 = XNEWVEC (uchar, size2);
+ }
+ do
+ {
+ if ((cpp_num_part) size2 > total2)
+ size2 = total2;
+ count = read (file->fd, buf2, size2);
+ if (count < 0)
+ {
+ cpp_errno_filename (pfile, CPP_DL_ERROR, file->path,
+ params->loc);
+ if (buf2 != buf)
+ free (buf2);
+ free (buf);
+ goto fail;
+ }
+ total2 -= count;
+ }
+ while (total2);
+ if (buf2 != buf)
+ free (buf2);
+ }
+
while ((count = read (file->fd, buf + total, size - total)) > 0)
{
total += count;
@@ -1377,7 +1430,10 @@ _cpp_stack_embed (cpp_reader *pfile, const char *fname,
bool angle,
file->limit = total;
}
else if (!regular)
- file->limit = total;
+ {
+ file->offset = params->offset;
+ file->limit = total;
+ }
file->buffer_start = buf;
file->buffer = buf;
@@ -1386,9 +1442,22 @@ _cpp_stack_embed (cpp_reader *pfile, const char *fname,
bool angle,
file->fd = -1;
}
else if (params->has_embed)
- return file->limit && params->limit ? 1 : 2;
+ {
+ if (params->offset - file->offset > file->limit)
+ return 2;
+ size_t limit = file->limit - (params->offset - file->offset);
+ return limit && params->limit ? 1 : 2;
+ }
+ const uchar *buffer = file->buffer;
size_t limit = file->limit;
+ if (params->offset - file->offset > limit)
+ limit = 0;
+ else
+ {
+ buffer += params->offset - file->offset;
+ limit -= params->offset - file->offset;
+ }
if (params->limit < limit)
limit = params->limit;
@@ -1412,20 +1481,20 @@ _cpp_stack_embed (cpp_reader *pfile, const char *fname,
bool angle,
size_t len = 0;
for (size_t i = 0; i < limit; ++i)
{
- if (file->buffer[i] < 10)
+ if (buffer[i] < 10)
len += 2;
- else if (file->buffer[i] < 100)
+ else if (buffer[i] < 100)
len += 3;
#if UCHAR_MAX == 255
else
len += 4;
#else
- else if (file->buffer[i] < 1000)
+ else if (buffer[i] < 1000)
len += 4;
else
{
char buf[64];
- len += sprintf (buf, "%d", file->buffer[i]) + 1;
+ len += sprintf (buf, "%d", buffer[i]) + 1;
}
#endif
if (len > INTTYPE_MAXIMUM (ssize_t))
@@ -1479,7 +1548,7 @@ _cpp_stack_embed (cpp_reader *pfile, const char *fname,
bool angle,
if (i == 0)
tok->flags |= PREV_WHITE;
tok->val.str.text = s;
- tok->val.str.len = sprintf ((char *) s, "%d", file->buffer[i]);
+ tok->val.str.len = sprintf ((char *) s, "%d", buffer[i]);
s += tok->val.str.len + 1;
if (tok == &pfile->directive_result)
tok = toks;
diff --git a/libcpp/internal.h b/libcpp/internal.h
index ff49c282aa36..ad0625af9554 100644
--- a/libcpp/internal.h
+++ b/libcpp/internal.h
@@ -637,7 +637,7 @@ struct cpp_embed_params
{
location_t loc;
bool has_embed;
- cpp_num_part limit;
+ cpp_num_part limit, offset;
cpp_embed_params_tokens prefix, suffix, if_empty;
};
