X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=liblttng-ust%2Flttng-ust-elf.c;h=c9d2b6b3c406dcb33a8a39dfaab51af7dbe39917;hb=68d4b11c7235d97e14a4e1d20004a7a839d5f880;hp=ce58539e67880e853224a862c6aaed3ca6094b7a;hpb=83215d66bbc361b174835895a3f6166e7c2fcd86;p=lttng-ust.git

diff --git a/liblttng-ust/lttng-ust-elf.c b/liblttng-ust/lttng-ust-elf.c
index ce58539e..c9d2b6b3 100644
--- a/liblttng-ust/lttng-ust-elf.c
+++ b/liblttng-ust/lttng-ust-elf.c
@@ -16,6 +16,7 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
  */
 
+#define _GNU_SOURCE
 #include <helper.h>
 #include <string.h>
 #include <lttng/align.h>
@@ -315,6 +316,18 @@ error:
 	return NULL;
 }
 
+/*
+ * Test whether the ELF file is position independent code (PIC)
+ */
+uint8_t lttng_ust_elf_is_pic(struct lttng_ust_elf *elf)
+{
+	/*
+	 * PIC has and e_type value of ET_DYN, see ELF specification
+	 * version 1.1 p. 1-3.
+	 */
+	return elf->ehdr->e_type == ET_DYN;
+}
+
 /*
  * Destroy the given lttng_ust_elf instance.
  */
@@ -341,7 +354,7 @@ void lttng_ust_elf_destroy(struct lttng_ust_elf *elf)
 int lttng_ust_elf_get_memsz(struct lttng_ust_elf *elf, uint64_t *memsz)
 {
 	uint16_t i;
-	uint64_t _memsz = 0;
+	uint64_t low_addr = UINT64_MAX, high_addr = 0;
 
 	if (!elf || !memsz) {
 		goto error;
@@ -349,7 +362,6 @@ int lttng_ust_elf_get_memsz(struct lttng_ust_elf *elf, uint64_t *memsz)
 
 	for (i = 0; i < elf->ehdr->e_phnum; ++i) {
 		struct lttng_ust_elf_phdr *phdr;
-		uint64_t align;
 
 		phdr = lttng_ust_elf_get_phdr(elf, i);
 		if (!phdr) {
@@ -364,27 +376,19 @@ int lttng_ust_elf_get_memsz(struct lttng_ust_elf *elf, uint64_t *memsz)
 			goto next_loop;
 		}
 
-		/*
-		 * A p_align of 0 means no alignment, i.e. aligned to
-		 * 1 byte.
-		 */
-		align = phdr->p_align == 0 ? 1 : phdr->p_align;
-		/* Align the start of the segment. */
-		_memsz += offset_align(_memsz, align);
-		_memsz += phdr->p_memsz;
-		/*
-		 * Add padding at the end of the segment, so it ends
-		 * on a multiple of the align value (which usually
-		 * means a page boundary). This makes the computation
-		 * valid even in cases where p_align would change from
-		 * one segment to the next.
-		 */
-		_memsz += offset_align(_memsz, align);
+		low_addr = phdr->p_vaddr < low_addr ? phdr->p_vaddr : low_addr;
+		high_addr = phdr->p_vaddr + phdr->p_memsz > high_addr ?
+				phdr->p_vaddr + phdr->p_memsz : high_addr;
 	next_loop:
 		free(phdr);
 	}
 
-	*memsz = _memsz;
+	if (high_addr < low_addr) {
+		/* No PT_LOAD segments or corrupted data. */
+		goto error;
+	}
+
+	*memsz = high_addr - low_addr;
 	return 0;
 error:
 	return -1;
@@ -405,11 +409,10 @@ error:
 static
 int lttng_ust_elf_get_build_id_from_segment(
 	struct lttng_ust_elf *elf, uint8_t **build_id, size_t *length,
-	off_t offset, off_t segment_end, int *found)
+	off_t offset, off_t segment_end)
 {
 	uint8_t *_build_id = NULL;	/* Silence old gcc warning. */
 	size_t _length = 0;		/* Silence old gcc warning. */
-	int _found = 0;
 
 	while (offset < segment_end) {
 		struct lttng_ust_elf_nhdr nhdr;
@@ -466,16 +469,14 @@ int lttng_ust_elf_get_build_id_from_segment(
 			goto error;
 		}
 
-		_found = 1;
 		break;
 	}
 
-	if (_found) {
+	if (_build_id) {
 		*build_id = _build_id;
 		*length = _length;
 	}
 
-	*found = _found;
 	return 0;
 error:
 	free(_build_id);
@@ -501,7 +502,6 @@ int lttng_ust_elf_get_build_id(struct lttng_ust_elf *elf, uint8_t **build_id,
 	uint16_t i;
 	uint8_t *_build_id = NULL;	/* Silence old gcc warning. */
 	size_t _length = 0;		/* Silence old gcc warning. */
-	int _found = 0;
 
 	if (!elf || !build_id || !length || !found) {
 		goto error;
@@ -525,26 +525,28 @@ int lttng_ust_elf_get_build_id(struct lttng_ust_elf *elf, uint8_t **build_id,
 		offset = phdr->p_offset;
 		segment_end = offset + phdr->p_filesz;
 		ret = lttng_ust_elf_get_build_id_from_segment(
-			elf, &_build_id, &_length, offset, segment_end,
-			&_found);
+			elf, &_build_id, &_length, offset, segment_end);
 	next_loop:
 		free(phdr);
 		if (ret) {
 			goto error;
 		}
-		if (_found) {
+		if (_build_id) {
 			break;
 		}
 	}
 
-	if (_found) {
+	if (_build_id) {
 		*build_id = _build_id;
 		*length = _length;
+		*found = 1;
+	} else {
+		*found = 0;
 	}
 
-	*found = _found;
 	return 0;
 error:
+	free(_build_id);
 	return -1;
 }
 
@@ -560,16 +562,14 @@ error:
  */
 int lttng_ust_elf_get_debug_link_from_section(struct lttng_ust_elf *elf,
 					char **filename, uint32_t *crc,
-					int *found,
 					struct lttng_ust_elf_shdr *shdr)
 {
-	int _found = 0;
 	char *_filename = NULL;		/* Silence old gcc warning. */
 	size_t filename_len;
 	char *section_name = NULL;
 	uint32_t _crc = 0;		/* Silence old gcc warning. */
 
-	if (!elf || !filename || !crc || !found || !shdr) {
+	if (!elf || !filename || !crc || !shdr) {
 		goto error;
 	}
 
@@ -612,15 +612,12 @@ int lttng_ust_elf_get_debug_link_from_section(struct lttng_ust_elf *elf,
 		_crc = bswap_32(_crc);
 	}
 
-	_found = 1;
-
 end:
 	free(section_name);
-	if (_found) {
+	if (_filename) {
 		*filename = _filename;
 		*crc = _crc;
 	}
-	*found = _found;
 
 	return 0;
 
@@ -645,7 +642,6 @@ int lttng_ust_elf_get_debug_link(struct lttng_ust_elf *elf, char **filename,
 {
 	int ret;
 	uint16_t i;
-	int _found = 0;
 	char *_filename = NULL;		/* Silence old gcc warning. */
 	uint32_t _crc = 0;		/* Silence old gcc warning. */
 
@@ -662,24 +658,28 @@ int lttng_ust_elf_get_debug_link(struct lttng_ust_elf *elf, char **filename,
 		}
 
 		ret = lttng_ust_elf_get_debug_link_from_section(
-			elf, &_filename, &_crc, &_found, shdr);
+			elf, &_filename, &_crc, shdr);
 		free(shdr);
 
 		if (ret) {
 			goto error;
 		}
-		if (_found) {
+		if (_filename) {
 			break;
 		}
 	}
 
-	if (_found) {
+	if (_filename) {
 		*filename = _filename;
 		*crc = _crc;
+		*found = 1;
+	} else {
+		*found = 0;
 	}
 
-	*found = _found;
 	return 0;
+
 error:
+	free(_filename);
 	return -1;
 }