From 8e2aed3f18adc14ec586ef717e396bcac4473dd7 Mon Sep 17 00:00:00 2001 From: Antoine Busque Date: Thu, 2 Jul 2015 11:55:53 -0400 Subject: [PATCH] Add memory size, build id, and debug link info to statedump and dl Implement a minimal ELF parser allowing to compute an executable's in-memory size and to read its build id and debug link info, if any, at runtime. This is performed during base address statedump, and on dlopen when using the `liblttng-ust-dl.so` helper. This adds a `memsz` field to `lttng_ust_statedump:soinfo` and `lttng_ust_dl:dlopen`. Also adds two events to both providers, `build_id` and `debug_link`, which are only traced when the corresponding information is found in the executable file. They can be matched with the corresponding `soinfo` or `dlopen` via the `baddr` field shared amongst all the events. Build ID and debug link are standard methods of identifying and retrieving debug information corresponding to a specific version of an executable. The fields `size` and `mtime` from the existing `soinfo` and `dlopen` events have been removed as they provided no valuable information for analysis, whereas build ID or debug link allow unambiguous retrieval of the debug information, and the on-disk `size` is superseded by the in-memory `memsz`. Signed-off-by: Antoine Busque Signed-off-by: Mathieu Desnoyers --- include/lttng/ust-elf.h | 228 +++++++ liblttng-ust-dl/lttng-ust-dl.c | 95 ++- liblttng-ust-dl/ust_dl.h | 38 +- liblttng-ust/Makefile.am | 2 + liblttng-ust/lttng-ust-elf.c | 649 ++++++++++++++++++++ liblttng-ust/lttng-ust-statedump-provider.h | 36 +- liblttng-ust/lttng-ust-statedump.c | 119 +++- liblttng-ust/lttng-ust-statedump.h | 1 + 8 files changed, 1113 insertions(+), 55 deletions(-) create mode 100644 include/lttng/ust-elf.h create mode 100644 liblttng-ust/lttng-ust-elf.c diff --git a/include/lttng/ust-elf.h b/include/lttng/ust-elf.h new file mode 100644 index 00000000..41e3c9b7 --- /dev/null +++ b/include/lttng/ust-elf.h @@ -0,0 +1,228 @@ +#ifndef _LTTNG_UST_ELF_H +#define _LTTNG_UST_ELF_H +/* + * Copyright (C) 2015 Antoine Busque + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include +#include +#include +#include +#include +#include + +/* + * Determine native endianness in order to convert when reading an ELF + * file if there is a mismatch. + */ +#if BYTE_ORDER == LITTLE_ENDIAN +#define NATIVE_ELF_ENDIANNESS ELFDATA2LSB +#else +#define NATIVE_ELF_ENDIANNESS ELFDATA2MSB +#endif + +/* + * The size in bytes of the debug link CRC as contained in an ELF + * section. + */ +#define ELF_CRC_SIZE 4 +/* + * ELF notes are aligned on 4 bytes. ref: ELF specification version + * 1.1 p. 2-5. + */ +#define ELF_NOTE_ENTRY_ALIGN 4 +/* + * Within an ELF note, the `desc` field is also aligned on 4 + * bytes. ref: ELF specification version 1.1 p. 2-5. + */ +#define ELF_NOTE_DESC_ALIGN 4 + +#define bswap(x) \ + do { \ + switch (sizeof(x)) { \ + case 8: \ + x = bswap_64(x); \ + break; \ + case 4: \ + x = bswap_32(x); \ + break; \ + case 2: \ + x = bswap_16(x); \ + break; \ + case 1: \ + break; \ + default: \ + abort(); \ + } \ + } while (0) + +#define bswap_phdr(phdr) \ + do { \ + bswap((phdr).p_type); \ + bswap((phdr).p_offset); \ + bswap((phdr).p_filesz); \ + bswap((phdr).p_memsz); \ + bswap((phdr).p_align); \ + } while (0) + +#define bswap_shdr(shdr) \ + do { \ + bswap((shdr).sh_name); \ + bswap((shdr).sh_type); \ + bswap((shdr).sh_flags); \ + bswap((shdr).sh_addr); \ + bswap((shdr).sh_offset); \ + bswap((shdr).sh_size); \ + bswap((shdr).sh_link); \ + bswap((shdr).sh_info); \ + bswap((shdr).sh_addralign); \ + bswap((shdr).sh_entsize); \ + } while (0) + +#define bswap_ehdr(ehdr) \ + do { \ + bswap((ehdr).e_type); \ + bswap((ehdr).e_machine); \ + bswap((ehdr).e_version); \ + bswap((ehdr).e_entry); \ + bswap((ehdr).e_phoff); \ + bswap((ehdr).e_shoff); \ + bswap((ehdr).e_flags); \ + bswap((ehdr).e_ehsize); \ + bswap((ehdr).e_phentsize); \ + bswap((ehdr).e_phnum); \ + bswap((ehdr).e_shentsize); \ + bswap((ehdr).e_shnum); \ + bswap((ehdr).e_shstrndx); \ + } while (0) + +#define copy_phdr(src_phdr, dst_phdr) \ + do { \ + (dst_phdr).p_type = (src_phdr).p_type; \ + (dst_phdr).p_offset = (src_phdr).p_offset; \ + (dst_phdr).p_filesz = (src_phdr).p_filesz; \ + (dst_phdr).p_memsz = (src_phdr).p_memsz; \ + (dst_phdr).p_align = (src_phdr).p_align; \ + } while (0) + +#define copy_shdr(src_shdr, dst_shdr) \ + do { \ + (dst_shdr).sh_name = (src_shdr).sh_name; \ + (dst_shdr).sh_type = (src_shdr).sh_type; \ + (dst_shdr).sh_flags = (src_shdr).sh_flags; \ + (dst_shdr).sh_addr = (src_shdr).sh_addr; \ + (dst_shdr).sh_offset = (src_shdr).sh_offset; \ + (dst_shdr).sh_size = (src_shdr).sh_size; \ + (dst_shdr).sh_link = (src_shdr).sh_link; \ + (dst_shdr).sh_info = (src_shdr).sh_info; \ + (dst_shdr).sh_addralign = (src_shdr).sh_addralign; \ + (dst_shdr).sh_entsize = (src_shdr).sh_entsize; \ + } while (0) + +#define copy_ehdr(src_ehdr, dst_ehdr) \ + do { \ + (dst_ehdr).e_type = (src_ehdr).e_type; \ + (dst_ehdr).e_machine = (src_ehdr).e_machine; \ + (dst_ehdr).e_version = (src_ehdr).e_version; \ + (dst_ehdr).e_entry = (src_ehdr).e_entry; \ + (dst_ehdr).e_phoff = (src_ehdr).e_phoff; \ + (dst_ehdr).e_shoff = (src_ehdr).e_shoff; \ + (dst_ehdr).e_flags = (src_ehdr).e_flags; \ + (dst_ehdr).e_ehsize = (src_ehdr).e_ehsize; \ + (dst_ehdr).e_phentsize = (src_ehdr).e_phentsize; \ + (dst_ehdr).e_phnum = (src_ehdr).e_phnum; \ + (dst_ehdr).e_shentsize = (src_ehdr).e_shentsize; \ + (dst_ehdr).e_shnum = (src_ehdr).e_shnum; \ + (dst_ehdr).e_shstrndx = (src_ehdr).e_shstrndx; \ + } while (0) + +struct lttng_ust_elf_ehdr { + uint16_t e_type; + uint16_t e_machine; + uint32_t e_version; + uint64_t e_entry; + uint64_t e_phoff; + uint64_t e_shoff; + uint32_t e_flags; + uint16_t e_ehsize; + uint16_t e_phentsize; + uint16_t e_phnum; + uint16_t e_shentsize; + uint16_t e_shnum; + uint16_t e_shstrndx; +}; + +struct lttng_ust_elf_phdr { + uint32_t p_type; + uint64_t p_offset; + uint64_t p_filesz; + uint64_t p_memsz; + uint64_t p_align; +}; + +struct lttng_ust_elf_shdr { + uint32_t sh_name; + uint32_t sh_type; + uint64_t sh_flags; + uint64_t sh_addr; + uint64_t sh_offset; + uint64_t sh_size; + uint32_t sh_link; + uint32_t sh_info; + uint64_t sh_addralign; + uint64_t sh_entsize; +}; + +struct lttng_ust_elf_nhdr { + uint32_t n_namesz; + uint32_t n_descsz; + uint32_t n_type; +}; + +struct lttng_ust_elf { + /* Offset in bytes to start of section names string table. */ + uint64_t section_names_offset; + /* Size in bytes of section names string table. */ + uint64_t section_names_size; + char *path; + FILE *file; + struct lttng_ust_elf_ehdr *ehdr; + uint8_t bitness; + uint8_t endianness; +}; + +static inline +int is_elf_32_bit(struct lttng_ust_elf *elf) +{ + return elf->bitness == ELFCLASS32; +} + +static inline +int is_elf_native_endian(struct lttng_ust_elf *elf) +{ + return elf->endianness == NATIVE_ELF_ENDIANNESS; +} + +struct lttng_ust_elf *lttng_ust_elf_create(const char *path); +void lttng_ust_elf_destroy(struct lttng_ust_elf *elf); +int lttng_ust_elf_get_memsz(struct lttng_ust_elf *elf, uint64_t *memsz); +int lttng_ust_elf_get_build_id(struct lttng_ust_elf *elf, uint8_t **build_id, + size_t *length, int *found); +int lttng_ust_elf_get_debug_link(struct lttng_ust_elf *elf, char **filename, + uint32_t *crc, int *found); + +#endif /* _LTTNG_UST_ELF_H */ diff --git a/liblttng-ust-dl/lttng-ust-dl.c b/liblttng-ust-dl/lttng-ust-dl.c index d366f64f..d6b80714 100644 --- a/liblttng-ust-dl/lttng-ust-dl.c +++ b/liblttng-ust-dl/lttng-ust-dl.c @@ -1,5 +1,6 @@ /* * Copyright (C) 2013 Paul Woegerer + * Copyright (C) 2015 Antoine Busque * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public @@ -18,21 +19,18 @@ #define _LGPL_SOURCE #define _GNU_SOURCE -#include -#include -#include -#include -#include + #include +#include #include -#include -#include -#include -#include +#include + +#include +#include #include "usterr-signal-safe.h" -#include -#include +/* Include link.h last else it conflicts with ust-dlfcn. */ +#include #define TRACEPOINT_DEFINE #include "ust_dl.h" @@ -45,7 +43,7 @@ void *_lttng_ust_dl_libc_dlopen(const char *filename, int flag) { if (!__lttng_ust_plibc_dlopen) { __lttng_ust_plibc_dlopen = dlsym(RTLD_NEXT, "dlopen"); - if (__lttng_ust_plibc_dlopen == NULL) { + if (!__lttng_ust_plibc_dlopen) { fprintf(stderr, "%s\n", dlerror()); return NULL; } @@ -58,7 +56,7 @@ int _lttng_ust_dl_libc_dlclose(void *handle) { if (!__lttng_ust_plibc_dlclose) { __lttng_ust_plibc_dlclose = dlsym(RTLD_NEXT, "dlclose"); - if (__lttng_ust_plibc_dlclose == NULL) { + if (!__lttng_ust_plibc_dlclose) { fprintf(stderr, "%s\n", dlerror()); return -1; } @@ -70,33 +68,77 @@ static void lttng_ust_dl_dlopen(void *so_base, const char *so_name, void *ip) { char resolved_path[PATH_MAX]; - struct stat sostat; + struct lttng_ust_elf *elf; + uint64_t memsz; + uint8_t *build_id; + size_t build_id_len; + char *dbg_file; + uint32_t crc; + int has_build_id = 0, has_debug_link = 0; + int ret; if (!realpath(so_name, resolved_path)) { ERR("could not resolve path '%s'", so_name); return; } - if (stat(resolved_path, &sostat)) { - ERR("could not access file status for %s", resolved_path); + elf = lttng_ust_elf_create(resolved_path); + if (!elf) { + ERR("could not acces file %s", resolved_path); return; } + ret = lttng_ust_elf_get_memsz(elf, &memsz); + if (ret) { + goto end; + } + ret = lttng_ust_elf_get_build_id( + elf, &build_id, &build_id_len, &has_build_id); + if (ret) { + goto end; + } + ret = lttng_ust_elf_get_debug_link( + elf, &dbg_file, &crc, &has_debug_link); + if (ret) { + goto end; + } + tracepoint(lttng_ust_dl, dlopen, - so_base, resolved_path, sostat.st_size, sostat.st_mtime, ip); + ip, so_base, resolved_path, memsz); + + if (has_build_id) { + tracepoint(lttng_ust_dl, build_id, + ip, so_base, build_id, build_id_len); + free(build_id); + } + + if (has_debug_link) { + tracepoint(lttng_ust_dl, debug_link, + ip, so_base, dbg_file, crc); + free(dbg_file); + } + +end: + lttng_ust_elf_destroy(elf); return; } void *dlopen(const char *filename, int flag) { - void *handle = _lttng_ust_dl_libc_dlopen(filename, flag); + void *handle; + + handle = _lttng_ust_dl_libc_dlopen(filename, flag); if (__tracepoint_ptrs_registered && handle) { struct link_map *p = NULL; - if (dlinfo(handle, RTLD_DI_LINKMAP, &p) != -1 && p != NULL - && p->l_addr != 0) + int ret; + + ret = dlinfo(handle, RTLD_DI_LINKMAP, &p); + if (ret != -1 && p != NULL && p->l_addr != 0) { lttng_ust_dl_dlopen((void *) p->l_addr, p->l_name, __builtin_return_address(0)); + } } + return handle; } @@ -104,10 +146,15 @@ int dlclose(void *handle) { if (__tracepoint_ptrs_registered && handle) { struct link_map *p = NULL; - if (dlinfo(handle, RTLD_DI_LINKMAP, &p) != -1 && p != NULL - && p->l_addr != 0) - tracepoint(lttng_ust_dl, dlclose, (void *) p->l_addr, - __builtin_return_address(0)); + int ret; + + ret = dlinfo(handle, RTLD_DI_LINKMAP, &p); + if (ret != -1 && p != NULL && p->l_addr != 0) { + tracepoint(lttng_ust_dl, dlclose, + __builtin_return_address(0), + (void *) p->l_addr); + } } + return _lttng_ust_dl_libc_dlclose(handle); } diff --git a/liblttng-ust-dl/ust_dl.h b/liblttng-ust-dl/ust_dl.h index ddab5306..e87ec122 100644 --- a/liblttng-ust-dl/ust_dl.h +++ b/liblttng-ust-dl/ust_dl.h @@ -10,6 +10,7 @@ extern "C" { /* * Copyright (C) 2013 Paul Woegerer + * Copyright (C) 2015 Antoine Busque * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal @@ -37,18 +38,45 @@ extern "C" { #include TRACEPOINT_EVENT(lttng_ust_dl, dlopen, - TP_ARGS(void *, baddr, const char*, sopath, int64_t, size, - int64_t, mtime, void *, ip), + TP_ARGS(void *, ip, void *, baddr, const char*, sopath, + uint64_t, memsz), TP_FIELDS( ctf_integer_hex(void *, baddr, baddr) + ctf_integer(uint64_t, memsz, memsz) ctf_string(sopath, sopath) - ctf_integer(int64_t, size, size) - ctf_integer(int64_t, mtime, mtime) + ) +) + +TRACEPOINT_EVENT(lttng_ust_dl, build_id, + TP_ARGS( + void *, ip, + void *, baddr, + uint8_t *, build_id, + size_t, build_id_len + ), + TP_FIELDS( + ctf_integer_hex(void *, baddr, baddr) + ctf_sequence_hex(uint8_t, build_id, build_id, + size_t, build_id_len) + ) +) + +TRACEPOINT_EVENT(lttng_ust_dl, debug_link, + TP_ARGS( + void *, ip, + void *, baddr, + char *, filename, + uint32_t, crc + ), + TP_FIELDS( + ctf_integer_hex(void *, baddr, baddr) + ctf_integer(uint32_t, crc, crc) + ctf_string(filename, filename) ) ) TRACEPOINT_EVENT(lttng_ust_dl, dlclose, - TP_ARGS(void *, baddr, void *, ip), + TP_ARGS(void *, ip, void *, baddr), TP_FIELDS( ctf_integer_hex(void *, baddr, baddr) ) diff --git a/liblttng-ust/Makefile.am b/liblttng-ust/Makefile.am index 199fa03d..9166896e 100644 --- a/liblttng-ust/Makefile.am +++ b/liblttng-ust/Makefile.am @@ -36,6 +36,8 @@ liblttng_ust_runtime_la_SOURCES = \ lttng-filter-interpreter.c \ filter-bytecode.h \ lttng-hash-helper.h \ + lttng-ust-elf.c \ + lttng-ust-elf.h \ lttng-ust-statedump.c \ lttng-ust-statedump.h \ lttng-ust-statedump-provider.h \ diff --git a/liblttng-ust/lttng-ust-elf.c b/liblttng-ust/lttng-ust-elf.c new file mode 100644 index 00000000..f5c4f1a1 --- /dev/null +++ b/liblttng-ust/lttng-ust-elf.c @@ -0,0 +1,649 @@ +/* + * Copyright (C) 2015 Antoine Busque + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include +#include +#include +#include + +/* + * Retrieve the nth (where n is the `index` argument) phdr (program + * header) from the given elf instance. + * + * A pointer to the phdr is returned on success, NULL on failure. + */ +static +struct lttng_ust_elf_phdr *lttng_ust_elf_get_phdr(struct lttng_ust_elf *elf, + uint16_t index) +{ + struct lttng_ust_elf_phdr *phdr = NULL; + long offset; + + if (!elf) { + goto error; + } + + if (index >= elf->ehdr->e_phnum) { + goto error; + } + + phdr = zmalloc(sizeof(struct lttng_ust_elf_phdr)); + if (!phdr) { + goto error; + } + + offset = elf->ehdr->e_phoff + index * elf->ehdr->e_phentsize; + if (fseek(elf->file, offset, SEEK_SET)) { + goto error; + } + + if (is_elf_32_bit(elf)) { + Elf32_Phdr elf_phdr; + + if (!fread(&elf_phdr, sizeof(elf_phdr), 1, elf->file)) { + goto error; + } + if (!is_elf_native_endian(elf)) { + bswap_phdr(elf_phdr); + } + copy_phdr(elf_phdr, *phdr); + } else { + Elf64_Phdr elf_phdr; + + if (!fread(&elf_phdr, sizeof(elf_phdr), 1, elf->file)) { + goto error; + } + if (!is_elf_native_endian(elf)) { + bswap_phdr(elf_phdr); + } + copy_phdr(elf_phdr, *phdr); + } + + return phdr; + +error: + free(phdr); + return NULL; +} + +/* + * Retrieve the nth (where n is the `index` argument) shdr (section + * header) from the given elf instance. + * + * A pointer to the shdr is returned on success, NULL on failure. + */ +static +struct lttng_ust_elf_shdr *lttng_ust_elf_get_shdr(struct lttng_ust_elf *elf, + uint16_t index) +{ + struct lttng_ust_elf_shdr *shdr = NULL; + long offset; + + if (!elf) { + goto error; + } + + if (index >= elf->ehdr->e_shnum) { + goto error; + } + + shdr = zmalloc(sizeof(struct lttng_ust_elf_shdr)); + if (!shdr) { + goto error; + } + + offset = elf->ehdr->e_shoff + index * elf->ehdr->e_shentsize; + if (fseek(elf->file, offset, SEEK_SET)) { + goto error; + } + + if (is_elf_32_bit(elf)) { + Elf32_Shdr elf_shdr; + + if (!fread(&elf_shdr, sizeof(elf_shdr), 1, elf->file)) { + goto error; + } + if (!is_elf_native_endian(elf)) { + bswap_shdr(elf_shdr); + } + copy_shdr(elf_shdr, *shdr); + } else { + Elf64_Shdr elf_shdr; + + if (!fread(&elf_shdr, sizeof(elf_shdr), 1, elf->file)) { + goto error; + } + if (!is_elf_native_endian(elf)) { + bswap_shdr(elf_shdr); + } + copy_shdr(elf_shdr, *shdr); + } + + return shdr; + +error: + free(shdr); + return NULL; +} + +/* + * Lookup a section's name from a given offset (usually from an shdr's + * sh_name value) in bytes relative to the beginning of the section + * names string table. + * + * If no name is found, NULL is returned. + */ +static +char *lttng_ust_elf_get_section_name(struct lttng_ust_elf *elf, uint32_t offset) +{ + char *name = NULL; + size_t len; + + if (!elf) { + goto error; + } + + if (offset >= elf->section_names_size) { + goto error; + } + + if (fseek(elf->file, elf->section_names_offset + offset, SEEK_SET)) { + goto error; + } + /* Note that len starts at 1, it is not an index. */ + for (len = 1; offset + len <= elf->section_names_size; ++len) { + switch (fgetc(elf->file)) { + case EOF: + goto error; + case '\0': + goto end; + default: + break; + } + } + + /* No name was found before the end of the table. */ + goto error; + +end: + name = zmalloc(sizeof(char) * len); + if (!name) { + goto error; + } + if (fseek(elf->file, elf->section_names_offset + offset, + SEEK_SET)) { + goto error; + } + if (!fgets(name, len, elf->file)) { + goto error; + } + + return name; + +error: + free(name); + return NULL; +} + +/* + * Create an instance of lttng_ust_elf for the ELF file located at + * `path`. + * + * Return a pointer to the instance on success, NULL on failure. + */ +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; + + elf = zmalloc(sizeof(struct lttng_ust_elf)); + if (!elf) { + goto error; + } + + elf->path = strdup(path); + if (!elf->path) { + goto error; + } + + elf->file = fopen(elf->path, "rb"); + if (!elf->file) { + goto error; + } + + if (!fread(e_ident, 1, EI_NIDENT, elf->file)) { + goto error; + } + elf->bitness = e_ident[EI_CLASS]; + elf->endianness = e_ident[EI_DATA]; + rewind(elf->file); + + elf->ehdr = zmalloc(sizeof(struct lttng_ust_elf_ehdr)); + if (!elf->ehdr) { + goto error; + } + + if (is_elf_32_bit(elf)) { + Elf32_Ehdr elf_ehdr; + + if (!fread(&elf_ehdr, sizeof(elf_ehdr), 1, elf->file)) { + goto error; + } + if (!is_elf_native_endian(elf)) { + bswap_ehdr(elf_ehdr); + } + copy_ehdr(elf_ehdr, *(elf->ehdr)); + } else { + Elf64_Ehdr elf_ehdr; + + if (!fread(&elf_ehdr, sizeof(elf_ehdr), 1, elf->file)) { + goto error; + } + if (!is_elf_native_endian(elf)) { + bswap_ehdr(elf_ehdr); + } + copy_ehdr(elf_ehdr, *(elf->ehdr)); + } + + section_names_shdr = lttng_ust_elf_get_shdr(elf, elf->ehdr->e_shstrndx); + if (!section_names_shdr) { + goto error; + } + + elf->section_names_offset = section_names_shdr->sh_offset; + elf->section_names_size = section_names_shdr->sh_size; + + free(section_names_shdr); + + return elf; + +error: + if (elf) { + free(elf->ehdr); + fclose(elf->file); + free(elf->path); + } + free(elf); + return NULL; +} + +/* + * Destroy the given lttng_ust_elf instance. + */ +void lttng_ust_elf_destroy(struct lttng_ust_elf *elf) +{ + if (!elf) { + return; + } + + free(elf->ehdr); + fclose(elf->file); + free(elf->path); + free(elf); +} + +/* + * Compute the total in-memory size of the ELF file, in bytes. + * + * Returns 0 if successful, -1 if not. On success, the memory size is + * returned through the out parameter `memsz`. + */ +int lttng_ust_elf_get_memsz(struct lttng_ust_elf *elf, uint64_t *memsz) +{ + uint16_t i; + uint64_t _memsz = 0; + + if (!elf || !memsz) { + goto error; + } + + 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) { + goto error; + } + + /* + * Only PT_LOAD segments contribute to memsz. Skip + * other segments. + */ + if (phdr->p_type != PT_LOAD) { + 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); + next_loop: + free(phdr); + } + + *memsz = _memsz; + return 0; +error: + return -1; +} + +/* + * Internal method used to try and get the build_id from a PT_NOTE + * segment ranging from `offset` to `segment_end`. + * + * If the function returns successfully, the out parameter `found` + * indicates whether the build id information was present in the + * segment or not. If `found` is not 0, the out parameters `build_id` + * and `length` will both have been set with the retrieved + * information. + * + * Returns 0 on success, -1 if an error occurred. + */ +static +int lttng_ust_elf_get_build_id_from_segment( + struct lttng_ust_elf *elf, uint8_t **build_id, size_t *length, + uint64_t offset, uint64_t segment_end, int *found) +{ + uint8_t *_build_id; + size_t _length; + int _found = 0; + + while (offset < segment_end) { + struct lttng_ust_elf_nhdr nhdr; + + /* Align start of note entry */ + offset += offset_align(offset, ELF_NOTE_ENTRY_ALIGN); + if (offset >= segment_end) { + break; + } + /* + * We seek manually because if the note isn't the + * build id the data following the header will not + * have been read. + */ + if (fseek(elf->file, offset, SEEK_SET)) { + goto error; + } + if (!fread(&nhdr, sizeof(nhdr), 1, elf->file)) { + goto error; + } + + if (!is_elf_native_endian(elf)) { + nhdr.n_namesz = bswap_32(nhdr.n_namesz); + nhdr.n_descsz = bswap_32(nhdr.n_descsz); + nhdr.n_type = bswap_32(nhdr.n_type); + } + + offset += sizeof(nhdr) + nhdr.n_namesz; + /* Align start of desc entry */ + offset += offset_align(offset, ELF_NOTE_DESC_ALIGN); + + if (nhdr.n_type != NT_GNU_BUILD_ID) { + /* + * Ignore non build id notes but still + * increase the offset. + */ + offset += nhdr.n_descsz; + continue; + } + + _length = nhdr.n_descsz; + _build_id = zmalloc(sizeof(uint8_t) * _length); + if (!build_id) { + goto error; + } + + if (fseek(elf->file, offset, SEEK_SET)) { + goto error; + } + if (!fread(_build_id, sizeof(*_build_id), _length, elf->file)) { + goto error; + } + + _found = 1; + break; + } + + if (_found) { + *build_id = _build_id; + *length = _length; + } + + *found = _found; + return 0; +error: + return -1; +} + +/* + * Retrieve a build ID (an array of bytes) from the corresponding + * section in the ELF file. The length of the build ID can be either + * 16 or 20 bytes depending on the method used to generate it, hence + * the length out parameter. + * + * If the function returns successfully, the out parameter `found` + * indicates whether the build id information was present in the ELF + * file or not. If `found` is not 0, the out parameters `build_id` and + * `length` will both have been set with the retrieved information. + * + * Returns 0 on success, -1 if an error occurred. + */ +int lttng_ust_elf_get_build_id(struct lttng_ust_elf *elf, uint8_t **build_id, + size_t *length, int *found) +{ + uint16_t i; + uint8_t *_build_id; + size_t _length; + int _found = 0; + + if (!elf || !build_id || !length || !found) { + goto error; + } + + for (i = 0; i < elf->ehdr->e_phnum; ++i) { + uint64_t offset, segment_end; + struct lttng_ust_elf_phdr *phdr; + int ret; + + phdr = lttng_ust_elf_get_phdr(elf, i); + if (!phdr) { + goto error; + } + + /* Build ID will be contained in a PT_NOTE segment. */ + if (phdr->p_type != PT_NOTE) { + goto next_loop; + } + + 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); + next_loop: + free(phdr); + if (ret) { + goto error; + } + if (_found) { + break; + } + } + + if (_found) { + *build_id = _build_id; + *length = _length; + } + + *found = _found; + return 0; +error: + return -1; +} + +/* + * Try to retrieve filename and CRC from given ELF section `shdr`. + * + * If the function returns successfully, the out parameter `found` + * indicates whether the debug link information was present in the ELF + * section or not. If `found` is not 0, the out parameters `filename` and + * `crc` will both have been set with the retrieved information. + * + * Returns 0 on success, -1 if an error occurred. + */ +static +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; + char *section_name = NULL; + uint32_t _crc; + + if (!elf || !filename || !crc || !found || !shdr) { + goto error; + } + + /* + * The .gnu_debuglink section is of type SHT_PROGBITS, + * skip the other sections. + */ + if (shdr->sh_type != SHT_PROGBITS) { + goto end; + } + + section_name = lttng_ust_elf_get_section_name(elf, + shdr->sh_name); + if (!section_name) { + goto end; + } + if (strcmp(section_name, ".gnu_debuglink")) { + goto end; + } + + /* + * The length of the filename is the sh_size excluding the CRC + * which comes after it in the section. + */ + _filename = zmalloc(sizeof(char) * (shdr->sh_size - ELF_CRC_SIZE)); + if (!_filename) { + goto error; + } + if (fseek(elf->file, shdr->sh_offset, SEEK_SET)) { + goto error; + } + if (!fread(_filename, sizeof(*_filename), shdr->sh_size - ELF_CRC_SIZE, + elf->file)) { + goto error; + } + if (!fread(&_crc, sizeof(_crc), 1, elf->file)) { + goto error; + } + if (!is_elf_native_endian(elf)) { + _crc = bswap_32(_crc); + } + + _found = 1; + +end: + free(section_name); + if (_found) { + *filename = _filename; + *crc = _crc; + } + *found = _found; + + return 0; + +error: + if (section_name) { + free(section_name); + } + + return -1; +} + +/* + * Retrieve filename and CRC from ELF's .gnu_debuglink section, if any. + * + * If the function returns successfully, the out parameter `found` + * indicates whether the debug link information was present in the ELF + * file or not. If `found` is not 0, the out parameters `filename` and + * `crc` will both have been set with the retrieved information. + * + * Returns 0 on success, -1 if an error occurred. + */ +int lttng_ust_elf_get_debug_link(struct lttng_ust_elf *elf, char **filename, + uint32_t *crc, int *found) +{ + int ret; + uint16_t i; + int _found = 0; + char *_filename; + uint32_t _crc; + + if (!elf || !filename || !crc || !found) { + goto error; + } + + for (i = 0; i < elf->ehdr->e_shnum; ++i) { + struct lttng_ust_elf_shdr *shdr = NULL; + + shdr = lttng_ust_elf_get_shdr(elf, i); + if (!shdr) { + goto error; + } + + ret = lttng_ust_elf_get_debug_link_from_section( + elf, &_filename, &_crc, &_found, shdr); + free(shdr); + + if (ret) { + goto error; + } + if (_found) { + break; + } + } + + if (_found) { + *filename = _filename; + *crc = _crc; + } + + *found = _found; + return 0; +error: + return -1; +} diff --git a/liblttng-ust/lttng-ust-statedump-provider.h b/liblttng-ust/lttng-ust-statedump-provider.h index adfbf9b2..5e212d9e 100644 --- a/liblttng-ust/lttng-ust-statedump-provider.h +++ b/liblttng-ust/lttng-ust-statedump-provider.h @@ -48,14 +48,40 @@ TRACEPOINT_EVENT(lttng_ust_statedump, soinfo, struct lttng_session *, session, void *, baddr, const char*, sopath, - int64_t, size, - int64_t, mtime - ), + uint64_t, memsz + ), TP_FIELDS( ctf_integer_hex(void *, baddr, baddr) + ctf_integer(uint64_t, memsz, memsz) ctf_string(sopath, sopath) - ctf_integer(int64_t, size, size) - ctf_integer(int64_t, mtime, mtime) + ) +) + +TRACEPOINT_EVENT(lttng_ust_statedump, build_id, + TP_ARGS( + struct lttng_session *, session, + void *, baddr, + uint8_t *, build_id, + size_t, build_id_len + ), + TP_FIELDS( + ctf_integer_hex(void *, baddr, baddr) + ctf_sequence_hex(uint8_t, build_id, build_id, + size_t, build_id_len) + ) +) + +TRACEPOINT_EVENT(lttng_ust_statedump, debug_link, + TP_ARGS( + struct lttng_session *, session, + void *, baddr, + char *, filename, + uint32_t, crc + ), + TP_FIELDS( + ctf_integer_hex(void *, baddr, baddr) + ctf_integer(uint32_t, crc, crc) + ctf_string(filename, filename) ) ) diff --git a/liblttng-ust/lttng-ust-statedump.c b/liblttng-ust/lttng-ust-statedump.c index 37f067ff..0c0a7bdd 100644 --- a/liblttng-ust/lttng-ust-statedump.c +++ b/liblttng-ust/lttng-ust-statedump.c @@ -19,19 +19,16 @@ #define _LGPL_SOURCE #define _GNU_SOURCE -#include -#include -#include -#include +#include #include -#include -#include -#include -#include #include +#include +#include +#include +#include -#include +#include #include "lttng-tracer-core.h" #include "lttng-ust-statedump.h" @@ -49,9 +46,12 @@ struct soinfo_data { void *owner; void *base_addr_ptr; const char *resolved_path; + char *dbg_file; + uint8_t *build_id; + uint64_t memsz; + size_t build_id_len; int vdso; - off_t size; - time_t mtime; + uint32_t crc; }; typedef void (*tracepoint_cb)(struct lttng_session *session, void *priv); @@ -92,9 +92,28 @@ void trace_soinfo_cb(struct lttng_session *session, void *priv) struct soinfo_data *so_data = (struct soinfo_data *) priv; tracepoint(lttng_ust_statedump, soinfo, - session, so_data->base_addr_ptr, - so_data->resolved_path, so_data->size, - so_data->mtime); + session, so_data->base_addr_ptr, + so_data->resolved_path, so_data->memsz); +} + +static +void trace_build_id_cb(struct lttng_session *session, void *priv) +{ + struct soinfo_data *so_data = (struct soinfo_data *) priv; + + tracepoint(lttng_ust_statedump, build_id, + session, so_data->base_addr_ptr, + so_data->build_id, so_data->build_id_len); +} + +static +void trace_debug_link_cb(struct lttng_session *session, void *priv) +{ + struct soinfo_data *so_data = (struct soinfo_data *) priv; + + tracepoint(lttng_ust_statedump, debug_link, + session, so_data->base_addr_ptr, + so_data->dbg_file, so_data->crc); } static @@ -109,20 +128,78 @@ void trace_end_cb(struct lttng_session *session, void *priv) tracepoint(lttng_ust_statedump, end, session); } +static +int get_elf_info(struct soinfo_data *so_data, int *has_build_id, + int *has_debug_link) { + struct lttng_ust_elf *elf; + int ret = 0; + + elf = lttng_ust_elf_create(so_data->resolved_path); + if (!elf) { + ret = -1; + goto end; + } + + ret = lttng_ust_elf_get_memsz(elf, &so_data->memsz); + if (ret) { + goto end; + } + + ret = lttng_ust_elf_get_build_id(elf, &so_data->build_id, + &so_data->build_id_len, has_build_id); + if (ret) { + goto end; + } + ret = lttng_ust_elf_get_debug_link(elf, &so_data->dbg_file, + &so_data->crc, has_debug_link); + if (ret) { + goto end; + } + +end: + lttng_ust_elf_destroy(elf); + return ret; +} + static int trace_baddr(struct soinfo_data *so_data) { - struct stat sostat; + int ret = 0, has_build_id = 0, has_debug_link = 0; + + if (!so_data->vdso) { + ret = get_elf_info(so_data, &has_build_id, &has_debug_link); + if (ret) { + goto end; + } + } else { + so_data->memsz = 0; + } - if (so_data->vdso || stat(so_data->resolved_path, &sostat)) { - sostat.st_size = 0; - sostat.st_mtime = -1; + ret = trace_statedump_event(trace_soinfo_cb, so_data->owner, so_data); + if (ret) { + goto end; } - so_data->size = sostat.st_size; - so_data->mtime = sostat.st_mtime; + if (has_build_id) { + ret = trace_statedump_event( + trace_build_id_cb, so_data->owner, so_data); + free(so_data->build_id); + if (ret) { + goto end; + } + } + + if (has_debug_link) { + ret = trace_statedump_event( + trace_debug_link_cb, so_data->owner, so_data); + free(so_data->dbg_file); + if (ret) { + goto end; + } + } - return trace_statedump_event(trace_soinfo_cb, so_data->owner, so_data); +end: + return ret; } static diff --git a/liblttng-ust/lttng-ust-statedump.h b/liblttng-ust/lttng-ust-statedump.h index e78774d5..48deb96d 100644 --- a/liblttng-ust/lttng-ust-statedump.h +++ b/liblttng-ust/lttng-ust-statedump.h @@ -3,6 +3,7 @@ /* * Copyright (C) 2013 Paul Woegerer + * Copyright (C) 2015 Antoine Busque * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public -- 2.34.1