Initial commit

6 files changed, 301 insertions, 0 deletions

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..798da5b
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,39 @@
+# Copyright © 2016 Intel Corporation
+#
+# Permission is hereby granted, free of charge, to any person obtaining a
+# copy of this software and associated documentation files (the "Software"),
+# to deal in the Software without restriction, including without limitation
+# the rights to use, copy, modify, merge, publish, distribute, sublicense,
+# and/or sell copies of the Software, and to permit persons to whom the
+# Software is furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice (including the next
+# paragraph) shall be included in all copies or substantial portions of the
+# Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+# THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+# IN THE SOFTWARE.
+
+LDFLAGS = -Wl,--build-id=sha1 -Wl,--default-script=build-id.lds
+
+all: build-id so-build-id
+
+build-id: test.o build-id.o
+	$(CC) $(LDFLAGS) $^ -o $@
+
+so-build-id: so-test.o libbuild-id.so
+	$(CC) $(LDFLAGS) $^ -o $@
+
+shared-build-id.o: build-id.c
+	$(CC) $(CPPFLAGS) $(CFLAGS) -fPIC -c $^ -o $@
+
+libbuild-id.so: shared-build-id.o
+	$(CC) -Wl,-Bsymbolic $(LDFLAGS) -shared $^ -o $@
+
+clean:
+	rm -f build-id so-build-id libbuild-id.so *.o
diff --git a/build-id.c b/build-id.c
new file mode 100644
index 0000000..94b2e5c
--- /dev/null
+++ b/build-id.c
@@ -0,0 +1,82 @@
+/* vim: set expandtab tabstop=4 softtabstop=4 shiftwidth=4: */
+/*
+ * Copyright © 2016 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <elf.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "build-id.h"
+
+extern const ElfW(Nhdr) __note_gnu_build_id_start[] __attribute__((weak));
+extern const ElfW(Nhdr) __note_gnu_build_id_end[] __attribute__((weak));
+
+void
+so_print(void)
+{
+    extern char etext, edata, end;
+    printf("Shared object:\n");
+    printf("    program text (etext)      %10p\n", &etext);
+    printf("    initialized data (edata)  %10p\n", &edata);
+    printf("    uninitialized data (end)  %10p\n", &end);
+    printf("    note section start        %10p\n", __note_gnu_build_id_start);
+    printf("    note section end          %10p\n", __note_gnu_build_id_end);
+}
+
+const ElfW(Nhdr) *
+build_id_find_nhdr(void)
+{
+    const ElfW(Nhdr) *nhdr = (void *)__note_gnu_build_id_start;
+
+    if (__note_gnu_build_id_start >= __note_gnu_build_id_end) {
+        fprintf(stderr, "No .note section\n");
+        return NULL;
+    }
+
+    while (nhdr->n_type != NT_GNU_BUILD_ID)
+    {
+        nhdr = (ElfW(Nhdr) *)
+            ((intptr_t)nhdr + sizeof(ElfW(Nhdr)) + nhdr->n_namesz + nhdr->n_descsz);
+
+        if (nhdr >= __note_gnu_build_id_end) {
+            fprintf(stderr, "No .note.gnu.build-id section found\n");
+            return NULL;
+        }
+    }
+
+    return nhdr;
+}
+
+ElfW(Word)
+build_id_length(const ElfW(Nhdr) *nhdr)
+{
+    return nhdr->n_descsz;
+}
+
+void
+build_id_read(const ElfW(Nhdr) *nhdr, unsigned char *build_id)
+{
+    memcpy(build_id,
+           (unsigned char *)nhdr + sizeof(ElfW(Nhdr)) + nhdr->n_namesz,
+           nhdr->n_descsz);
+}
diff --git a/build-id.h b/build-id.h
new file mode 100644
index 0000000..7a51c1e
--- /dev/null
+++ b/build-id.h
@@ -0,0 +1,45 @@
+/* vim: set expandtab tabstop=4 softtabstop=4 shiftwidth=4: */
+/*
+ * Copyright © 2016 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <elf.h>
+#include <stdio.h>
+#include <string.h>
+
+#if __x86_64__
+#  define ElfW(type) Elf64_##type
+#else
+#  define ElfW(type) Elf32_##type
+#endif
+
+void
+so_print(void);
+
+const ElfW(Nhdr) *
+build_id_find_nhdr(void);
+
+ElfW(Word)
+build_id_length(const ElfW(Nhdr) *nhdr);
+
+void
+build_id_read(const ElfW(Nhdr) *nhdr, unsigned char *build_id);
diff --git a/build-id.lds b/build-id.lds
new file mode 100644
index 0000000..ae54f64
--- /dev/null
+++ b/build-id.lds
@@ -0,0 +1,11 @@
+SECTIONS
+{
+	__note_gnu_build_id_start = .;
+}
+INSERT BEFORE .note.gnu.build-id;
+
+SECTIONS
+{
+	__note_gnu_build_id_end = .;
+}
+INSERT AFTER .note.gnu.build-id;
diff --git a/so-test.c b/so-test.c
new file mode 100644
index 0000000..0c5d74a
--- /dev/null
+++ b/so-test.c
@@ -0,0 +1,63 @@
+/* vim: set expandtab tabstop=4 softtabstop=4 shiftwidth=4: */
+/*
+ * Copyright © 2016 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "build-id.h"
+
+int
+main(int argc, char *argv[])
+{
+    extern char etext, edata, end;
+    extern const char __note_gnu_build_id_end[] __attribute__((weak));
+    extern const char __note_gnu_build_id_start[] __attribute__((weak));
+    printf("Executable:\n");
+    printf("    program text (etext)      %10p\n", &etext);
+    printf("    initialized data (edata)  %10p\n", &edata);
+    printf("    uninitialized data (end)  %10p\n", &end);
+    printf("    note section start        %10p\n", __note_gnu_build_id_start);
+    printf("    note section end          %10p\n", __note_gnu_build_id_end);
+
+    so_print();
+
+    const ElfW(Nhdr) *nhdr = build_id_find_nhdr();
+    if (!nhdr)
+        return -1;
+
+    ElfW(Word) len = build_id_length(nhdr);
+
+    unsigned char *build_id = malloc(len * sizeof(char));
+    if (!build_id)
+        return -1;
+
+    build_id_read(nhdr, build_id);
+
+    printf("Build ID: ");
+    for (ElfW(Word) i = 0; i < len; i++) {
+        printf("%02x", build_id[i]);
+    }
+    printf("\n");
+    return 0;
+}
diff --git a/test.c b/test.c
new file mode 100644
index 0000000..e8dae35
--- /dev/null
+++ b/test.c
@@ -0,0 +1,61 @@
+/* vim: set expandtab tabstop=4 softtabstop=4 shiftwidth=4: */
+/*
+ * Copyright © 2016 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "build-id.h"
+
+int
+main(int argc, char *argv[])
+{
+    extern char etext, edata, end;
+    extern const char __note_gnu_build_id_end[] __attribute__((weak));
+    extern const char __note_gnu_build_id_start[] __attribute__((weak));
+    printf("Executable:\n");
+    printf("    program text (etext)      %10p\n", &etext);
+    printf("    initialized data (edata)  %10p\n", &edata);
+    printf("    uninitialized data (end)  %10p\n", &end);
+    printf("    note section start        %10p\n", __note_gnu_build_id_start);
+    printf("    note section end          %10p\n", __note_gnu_build_id_end);
+
+    const ElfW(Nhdr) *nhdr = build_id_find_nhdr();
+    if (!nhdr)
+        return -1;
+
+    ElfW(Word) len = build_id_length(nhdr);
+
+    unsigned char *build_id = malloc(len * sizeof(char));
+    if (!build_id)
+        return -1;
+
+    build_id_read(nhdr, build_id);
+
+    printf("Build ID: ");
+    for (ElfW(Word) i = 0; i < len; i++) {
+        printf("%02x", build_id[i]);
+    }
+    printf("\n");
+    return 0;
+}