From 405be6583fc840d2ad298516edb267281bc2c4dc Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Mon, 31 Aug 2015 16:50:50 -0400 Subject: [PATCH] baddr statedump: remove dependency on file streams None of the rest of UST used by applications use file streams (only the sessiond uses a file streams for metadata). Therefore, use file descriptors directly for baddr statedump. Signed-off-by: Mathieu Desnoyers --- include/lttng/ust-elf.h | 2 +- liblttng-ust/lttng-tracer-core.h | 2 + liblttng-ust/lttng-ust-comm.c | 18 +++++ liblttng-ust/lttng-ust-elf.c | 123 ++++++++++++++++++++----------- 4 files changed, 100 insertions(+), 45 deletions(-) diff --git a/include/lttng/ust-elf.h b/include/lttng/ust-elf.h index 41e3c9b7..fee52f9e 100644 --- a/include/lttng/ust-elf.h +++ b/include/lttng/ust-elf.h @@ -199,7 +199,7 @@ struct lttng_ust_elf { /* Size in bytes of section names string table. */ uint64_t section_names_size; char *path; - FILE *file; + int fd; struct lttng_ust_elf_ehdr *ehdr; uint8_t bitness; uint8_t endianness; diff --git a/liblttng-ust/lttng-tracer-core.h b/liblttng-ust/lttng-tracer-core.h index 4e0d2c69..7d9beaaf 100644 --- a/liblttng-ust/lttng-tracer-core.h +++ b/liblttng-ust/lttng-tracer-core.h @@ -50,4 +50,6 @@ void lttng_ust_sockinfo_session_enabled(void *owner); void lttng_ust_malloc_wrapper_init(void); +ssize_t lttng_ust_read(int fd, void *buf, size_t len); + #endif /* _LTTNG_TRACER_CORE_H */ diff --git a/liblttng-ust/lttng-ust-comm.c b/liblttng-ust/lttng-ust-comm.c index 0a3de322..08e6299c 100644 --- a/liblttng-ust/lttng-ust-comm.c +++ b/liblttng-ust/lttng-ust-comm.c @@ -329,6 +329,24 @@ extern void lttng_ring_buffer_client_discard_exit(void); extern void lttng_ring_buffer_client_discard_rt_exit(void); extern void lttng_ring_buffer_metadata_client_exit(void); +ssize_t lttng_ust_read(int fd, void *buf, size_t len) +{ + ssize_t ret; + size_t copied = 0, to_copy = len; + + do { + ret = read(fd, buf + copied, to_copy); + if (ret > 0) { + copied += ret; + to_copy -= ret; + } + } while ((ret > 0 && to_copy > 0) + || (ret < 0 && errno == EINTR)); + if (ret > 0) { + ret = copied; + } + return ret; +} /* * Returns the HOME directory path. Caller MUST NOT free(3) the returned * pointer. diff --git a/liblttng-ust/lttng-ust-elf.c b/liblttng-ust/lttng-ust-elf.c index f5c4f1a1..0df70973 100644 --- a/liblttng-ust/lttng-ust-elf.c +++ b/liblttng-ust/lttng-ust-elf.c @@ -20,6 +20,13 @@ #include #include #include +#include +#include +#include +#include +#include "lttng-tracer-core.h" + +#define BUF_LEN 4096 /* * Retrieve the nth (where n is the `index` argument) phdr (program @@ -48,14 +55,15 @@ struct lttng_ust_elf_phdr *lttng_ust_elf_get_phdr(struct lttng_ust_elf *elf, } offset = elf->ehdr->e_phoff + index * elf->ehdr->e_phentsize; - if (fseek(elf->file, offset, SEEK_SET)) { + if (lseek(elf->fd, offset, SEEK_SET) < 0) { goto error; } if (is_elf_32_bit(elf)) { Elf32_Phdr elf_phdr; - if (!fread(&elf_phdr, sizeof(elf_phdr), 1, elf->file)) { + if (lttng_ust_read(elf->fd, &elf_phdr, sizeof(elf_phdr)) + < sizeof(elf_phdr)) { goto error; } if (!is_elf_native_endian(elf)) { @@ -65,7 +73,8 @@ struct lttng_ust_elf_phdr *lttng_ust_elf_get_phdr(struct lttng_ust_elf *elf, } else { Elf64_Phdr elf_phdr; - if (!fread(&elf_phdr, sizeof(elf_phdr), 1, elf->file)) { + if (lttng_ust_read(elf->fd, &elf_phdr, sizeof(elf_phdr)) + < sizeof(elf_phdr)) { goto error; } if (!is_elf_native_endian(elf)) { @@ -108,14 +117,15 @@ struct lttng_ust_elf_shdr *lttng_ust_elf_get_shdr(struct lttng_ust_elf *elf, } offset = elf->ehdr->e_shoff + index * elf->ehdr->e_shentsize; - if (fseek(elf->file, offset, SEEK_SET)) { + if (lseek(elf->fd, offset, SEEK_SET) < 0) { goto error; } if (is_elf_32_bit(elf)) { Elf32_Shdr elf_shdr; - if (!fread(&elf_shdr, sizeof(elf_shdr), 1, elf->file)) { + if (lttng_ust_read(elf->fd, &elf_shdr, sizeof(elf_shdr)) + < sizeof(elf_shdr)) { goto error; } if (!is_elf_native_endian(elf)) { @@ -125,7 +135,8 @@ struct lttng_ust_elf_shdr *lttng_ust_elf_get_shdr(struct lttng_ust_elf *elf, } else { Elf64_Shdr elf_shdr; - if (!fread(&elf_shdr, sizeof(elf_shdr), 1, elf->file)) { + if (lttng_ust_read(elf->fd, &elf_shdr, sizeof(elf_shdr)) + < sizeof(elf_shdr)) { goto error; } if (!is_elf_native_endian(elf)) { @@ -152,7 +163,7 @@ static char *lttng_ust_elf_get_section_name(struct lttng_ust_elf *elf, uint32_t offset) { char *name = NULL; - size_t len; + size_t len = 0, to_read; /* len does not include \0 */ if (!elf) { goto error; @@ -162,34 +173,45 @@ char *lttng_ust_elf_get_section_name(struct lttng_ust_elf *elf, uint32_t offset) goto error; } - if (fseek(elf->file, elf->section_names_offset + offset, SEEK_SET)) { + if (lseek(elf->fd, elf->section_names_offset + offset, SEEK_SET) < 0) { 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: + + to_read = elf->section_names_size - offset; + + /* Find first \0 after or at current location, remember len. */ + for (;;) { + char buf[BUF_LEN]; + ssize_t read_len; + size_t i; + + if (!to_read) { goto error; - case '\0': - goto end; - default: - break; } + read_len = lttng_ust_read(elf->fd, buf, + min_t(size_t, BUF_LEN, to_read)); + if (read_len <= 0) { + goto error; + } + for (i = 0; i < read_len; i++) { + if (buf[i] == '\0') { + len += i; + goto end; + } + } + len += read_len; + to_read -= read_len; } - - /* No name was found before the end of the table. */ - goto error; - end: - name = zmalloc(sizeof(char) * len); + name = zmalloc(sizeof(char) * (len + 1)); /* + 1 for \0 */ if (!name) { goto error; } - if (fseek(elf->file, elf->section_names_offset + offset, - SEEK_SET)) { + if (lseek(elf->fd, elf->section_names_offset + offset, + SEEK_SET) < 0) { goto error; } - if (!fgets(name, len, elf->file)) { + if (lttng_ust_read(elf->fd, name, len + 1) < len + 1) { goto error; } @@ -210,7 +232,7 @@ 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; + struct lttng_ust_elf *elf = NULL; elf = zmalloc(sizeof(struct lttng_ust_elf)); if (!elf) { @@ -222,17 +244,20 @@ struct lttng_ust_elf *lttng_ust_elf_create(const char *path) goto error; } - elf->file = fopen(elf->path, "rb"); - if (!elf->file) { + elf->fd = open(elf->path, O_RDONLY | O_CLOEXEC); + if (elf->fd < 0) { goto error; } - if (!fread(e_ident, 1, EI_NIDENT, elf->file)) { + if (lttng_ust_read(elf->fd, e_ident, EI_NIDENT) < EI_NIDENT) { goto error; } elf->bitness = e_ident[EI_CLASS]; elf->endianness = e_ident[EI_DATA]; - rewind(elf->file); + + if (lseek(elf->fd, 0, SEEK_SET) < 0) { + goto error; + } elf->ehdr = zmalloc(sizeof(struct lttng_ust_elf_ehdr)); if (!elf->ehdr) { @@ -242,7 +267,8 @@ struct lttng_ust_elf *lttng_ust_elf_create(const char *path) if (is_elf_32_bit(elf)) { Elf32_Ehdr elf_ehdr; - if (!fread(&elf_ehdr, sizeof(elf_ehdr), 1, elf->file)) { + if (lttng_ust_read(elf->fd, &elf_ehdr, sizeof(elf_ehdr)) + < sizeof(elf_ehdr)) { goto error; } if (!is_elf_native_endian(elf)) { @@ -252,7 +278,8 @@ struct lttng_ust_elf *lttng_ust_elf_create(const char *path) } else { Elf64_Ehdr elf_ehdr; - if (!fread(&elf_ehdr, sizeof(elf_ehdr), 1, elf->file)) { + if (lttng_ust_read(elf->fd, &elf_ehdr, sizeof(elf_ehdr)) + < sizeof(elf_ehdr)) { goto error; } if (!is_elf_native_endian(elf)) { @@ -270,16 +297,19 @@ struct lttng_ust_elf *lttng_ust_elf_create(const char *path) elf->section_names_size = section_names_shdr->sh_size; free(section_names_shdr); - return elf; error: if (elf) { free(elf->ehdr); - fclose(elf->file); + if (elf->fd >= 0) { + if (close(elf->fd)) { + abort(); + } + } free(elf->path); + free(elf); } - free(elf); return NULL; } @@ -293,7 +323,9 @@ void lttng_ust_elf_destroy(struct lttng_ust_elf *elf) } free(elf->ehdr); - fclose(elf->file); + if (close(elf->fd)) { + abort(); + } free(elf->path); free(elf); } @@ -379,6 +411,7 @@ int lttng_ust_elf_get_build_id_from_segment( while (offset < segment_end) { struct lttng_ust_elf_nhdr nhdr; + size_t read_len; /* Align start of note entry */ offset += offset_align(offset, ELF_NOTE_ENTRY_ALIGN); @@ -390,10 +423,11 @@ int lttng_ust_elf_get_build_id_from_segment( * build id the data following the header will not * have been read. */ - if (fseek(elf->file, offset, SEEK_SET)) { + if (lseek(elf->fd, offset, SEEK_SET) < 0) { goto error; } - if (!fread(&nhdr, sizeof(nhdr), 1, elf->file)) { + if (lttng_ust_read(elf->fd, &nhdr, sizeof(nhdr)) + < sizeof(nhdr)) { goto error; } @@ -422,10 +456,11 @@ int lttng_ust_elf_get_build_id_from_segment( goto error; } - if (fseek(elf->file, offset, SEEK_SET)) { + if (lseek(elf->fd, offset, SEEK_SET) < 0) { goto error; } - if (!fread(_build_id, sizeof(*_build_id), _length, elf->file)) { + read_len = sizeof(*_build_id) * _length; + if (lttng_ust_read(elf->fd, _build_id, read_len) < read_len) { goto error; } @@ -520,7 +555,6 @@ error: * * 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, @@ -528,6 +562,7 @@ int lttng_ust_elf_get_debug_link_from_section(struct lttng_ust_elf *elf, { int _found = 0; char *_filename; + size_t filename_len; char *section_name = NULL; uint32_t _crc; @@ -560,14 +595,14 @@ int lttng_ust_elf_get_debug_link_from_section(struct lttng_ust_elf *elf, if (!_filename) { goto error; } - if (fseek(elf->file, shdr->sh_offset, SEEK_SET)) { + if (lseek(elf->fd, shdr->sh_offset, SEEK_SET) < 0) { goto error; } - if (!fread(_filename, sizeof(*_filename), shdr->sh_size - ELF_CRC_SIZE, - elf->file)) { + filename_len = sizeof(*_filename) * (shdr->sh_size - ELF_CRC_SIZE); + if (lttng_ust_read(elf->fd, _filename, filename_len) < filename_len) { goto error; } - if (!fread(&_crc, sizeof(_crc), 1, elf->file)) { + if (lttng_ust_read(elf->fd, &_crc, sizeof(_crc)) < sizeof(_crc)) { goto error; } if (!is_elf_native_endian(elf)) { -- 2.34.1