X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=liblttng-ust%2Flttng-ust-elf.c;h=c073e7a545b64d349d3d7bb56932a24b9025f657;hb=f5c453e975e5d417590b9a1be2a9f8504db063c0;hp=e90626906b6ea72c24d19bbcd4a3b7cee92e0821;hpb=aaf93c608bb7591f0a5411c221a3ad3fbd8efdfd;p=lttng-ust.git

diff --git a/liblttng-ust/lttng-ust-elf.c b/liblttng-ust/lttng-ust-elf.c
index e9062690..c073e7a5 100644
--- a/liblttng-ust/lttng-ust-elf.c
+++ b/liblttng-ust/lttng-ust-elf.c
@@ -17,6 +17,7 @@
  */
 
 #define _GNU_SOURCE
+#define _LGPL_SOURCE
 #include <helper.h>
 #include <string.h>
 #include <lttng/align.h>
@@ -25,10 +26,16 @@
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <unistd.h>
+#include <stdbool.h>
+#include <ust-fd.h>
 #include "lttng-tracer-core.h"
 
 #define BUF_LEN	4096
 
+#ifndef NT_GNU_BUILD_ID
+# define NT_GNU_BUILD_ID	3
+#endif
+
 /*
  * Retrieve the nth (where n is the `index` argument) phdr (program
  * header) from the given elf instance.
@@ -236,21 +243,38 @@ struct lttng_ust_elf *lttng_ust_elf_create(const char *path)
 	uint8_t e_ident[EI_NIDENT];
 	struct lttng_ust_elf_shdr *section_names_shdr;
 	struct lttng_ust_elf *elf = NULL;
+	int ret, fd;
 
 	elf = zmalloc(sizeof(struct lttng_ust_elf));
 	if (!elf) {
 		goto error;
 	}
 
+
 	elf->path = strdup(path);
 	if (!elf->path) {
 		goto error;
 	}
 
-	elf->fd = open(elf->path, O_RDONLY | O_CLOEXEC);
-	if (elf->fd < 0) {
+	lttng_ust_lock_fd_tracker();
+	fd = open(elf->path, O_RDONLY | O_CLOEXEC);
+	if (fd < 0) {
+		lttng_ust_unlock_fd_tracker();
+		goto error;
+	}
+
+	ret = lttng_ust_add_fd_to_tracker(fd);
+	if (ret < 0) {
+		ret = close(fd);
+		if (ret) {
+			PERROR("close on elf->fd");
+		}
+		ret = -1;
+		lttng_ust_unlock_fd_tracker();
 		goto error;
 	}
+	elf->fd = ret;
+	lttng_ust_unlock_fd_tracker();
 
 	if (lttng_ust_read(elf->fd, e_ident, EI_NIDENT) < EI_NIDENT) {
 		goto error;
@@ -303,32 +327,46 @@ struct lttng_ust_elf *lttng_ust_elf_create(const char *path)
 	return elf;
 
 error:
-	if (elf) {
-		free(elf->ehdr);
-		if (elf->fd >= 0) {
-			if (close(elf->fd)) {
-				abort();
-			}
-		}
-		free(elf->path);
-		free(elf);
-	}
+	lttng_ust_elf_destroy(elf);
 	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.
  */
 void lttng_ust_elf_destroy(struct lttng_ust_elf *elf)
 {
+	int ret;
+
 	if (!elf) {
 		return;
 	}
 
-	free(elf->ehdr);
-	if (close(elf->fd)) {
-		abort();
+	if (elf->fd >= 0) {
+		lttng_ust_lock_fd_tracker();
+		ret = close(elf->fd);
+		if (!ret) {
+			lttng_ust_delete_fd_from_tracker(elf->fd);
+		} else {
+			PERROR("close");
+			abort();
+		}
+		lttng_ust_unlock_fd_tracker();
 	}
+
+	free(elf->ehdr);
 	free(elf->path);
 	free(elf);
 }
@@ -342,7 +380,7 @@ 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;
@@ -350,7 +388,6 @@ 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) {
@@ -365,27 +402,19 @@ 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 = min_t(uint64_t, low_addr, phdr->p_vaddr);
+		high_addr = max_t(uint64_t, high_addr,
+				phdr->p_vaddr + phdr->p_memsz);
 	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;