diff options
Diffstat (limited to 'lib/libpmcstat/libpmcstat_image.c')
| -rw-r--r-- | lib/libpmcstat/libpmcstat_image.c | 558 |
1 files changed, 558 insertions, 0 deletions
diff --git a/lib/libpmcstat/libpmcstat_image.c b/lib/libpmcstat/libpmcstat_image.c new file mode 100644 index 000000000000..69274dca31e8 --- /dev/null +++ b/lib/libpmcstat/libpmcstat_image.c @@ -0,0 +1,558 @@ +/*- + * Copyright (c) 2003-2008 Joseph Koshy + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <sys/types.h> +#include <sys/cpuset.h> +#include <sys/param.h> +#include <sys/endian.h> +#include <sys/pmc.h> +#include <sys/sysctl.h> +#include <sys/imgact_aout.h> +#include <sys/imgact_elf.h> + +#include <netinet/in.h> + +#include <assert.h> +#include <err.h> +#include <fcntl.h> +#include <pmc.h> +#include <pmclog.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sysexits.h> +#include <unistd.h> + +#include "libpmcstat.h" + +#define min(A,B) ((A) < (B) ? (A) : (B)) +#define max(A,B) ((A) > (B) ? (A) : (B)) + +/* + * Add the list of symbols in the given section to the list associated + * with the object. + */ +void +pmcstat_image_add_symbols(struct pmcstat_image *image, Elf *e, + Elf_Scn *scn, GElf_Shdr *sh) +{ + int firsttime; + size_t n, newsyms, nshsyms, nfuncsyms; + struct pmcstat_symbol *symptr; + char *fnname; + GElf_Sym sym; + Elf_Data *data; + + if ((data = elf_getdata(scn, NULL)) == NULL) + return; + + /* + * Determine the number of functions named in this + * section. + */ + + nshsyms = sh->sh_size / sh->sh_entsize; + for (n = nfuncsyms = 0; n < nshsyms; n++) { + if (gelf_getsym(data, (int) n, &sym) != &sym) + return; + if (GELF_ST_TYPE(sym.st_info) == STT_FUNC) + nfuncsyms++; + } + + if (nfuncsyms == 0) + return; + + /* + * Allocate space for the new entries. + */ + firsttime = image->pi_symbols == NULL; + symptr = reallocarray(image->pi_symbols, + image->pi_symcount + nfuncsyms, sizeof(*symptr)); + if (symptr == image->pi_symbols) /* realloc() failed. */ + return; + image->pi_symbols = symptr; + + /* + * Append new symbols to the end of the current table. + */ + symptr += image->pi_symcount; + + for (n = newsyms = 0; n < nshsyms; n++) { + if (gelf_getsym(data, (int) n, &sym) != &sym) + return; + if (GELF_ST_TYPE(sym.st_info) != STT_FUNC) + continue; + + if (sym.st_shndx == STN_UNDEF) + continue; + + if (!firsttime && pmcstat_symbol_search(image, sym.st_value)) + continue; /* We've seen this symbol already. */ + + if ((fnname = elf_strptr(e, sh->sh_link, sym.st_name)) + == NULL) + continue; + +#if defined(__aarch64__) || defined(__arm__) + /* Ignore ARM mapping symbols. */ + if (fnname[0] == '$' && + (fnname[1] == 'a' || fnname[1] == 't' || + fnname[1] == 'd' || fnname[1] == 'x')) + continue; + + /* + * Clear LSB from starting addresses for functions + * which execute in Thumb mode. We should perhaps + * only do this for functions in a $t mapping symbol + * range, but parsing mapping symbols would be a lot + * of work and function addresses shouldn't have the + * LSB set otherwise. + */ + sym.st_value &= ~1; +#endif + + symptr->ps_name = pmcstat_string_intern(fnname); + symptr->ps_start = sym.st_value - image->pi_vaddr; + symptr->ps_end = symptr->ps_start + sym.st_size; + + symptr++; + newsyms++; + } + + image->pi_symcount += newsyms; + if (image->pi_symcount == 0) + return; + + assert(newsyms <= nfuncsyms); + + /* + * Return space to the system if there were duplicates. + */ + if (newsyms < nfuncsyms) + image->pi_symbols = reallocarray(image->pi_symbols, + image->pi_symcount, sizeof(*symptr)); + + /* + * Keep the list of symbols sorted. + */ + qsort(image->pi_symbols, image->pi_symcount, sizeof(*symptr), + pmcstat_symbol_compare); + + /* + * Deal with function symbols that have a size of 'zero' by + * making them extend to the next higher address. These + * symbols are usually defined in assembly code. + */ + for (symptr = image->pi_symbols; + symptr < image->pi_symbols + (image->pi_symcount - 1); + symptr++) + if (symptr->ps_start == symptr->ps_end) + symptr->ps_end = (symptr+1)->ps_start; +} + +/* + * Record the fact that PC values from 'start' to 'end' come from + * image 'image'. + */ + +void +pmcstat_image_link(struct pmcstat_process *pp, struct pmcstat_image *image, + uintfptr_t start) +{ + struct pmcstat_pcmap *pcm, *pcmnew; + uintfptr_t offset; +#ifdef __powerpc__ + unsigned long kernbase; + size_t kernbase_len; +#endif + + assert(image->pi_type != PMCSTAT_IMAGE_UNKNOWN && + image->pi_type != PMCSTAT_IMAGE_INDETERMINABLE); + + /* + * It's possible to have images with nothing of value in .text + * legitimately. We shouldn't have any samples from this image, so + * don't bother with a map entry either. + */ + if (image->pi_start == 0 && image->pi_end == 0) + return; + + if ((pcmnew = malloc(sizeof(*pcmnew))) == NULL) + err(EX_OSERR, "ERROR: Cannot create a map entry"); + + /* + * PowerPC kernel is of DYN type and it has a base address + * where it is initially loaded, before being relocated. + * As the address in 'start' is where the kernel was relocated to, + * but the symbols always use the original base address, we need to + * subtract it to get the correct offset. + */ +#ifdef __powerpc__ + if (pp->pp_pid == -1) { + kernbase = 0; + kernbase_len = sizeof(kernbase); + if (sysctlbyname("kern.base_address", &kernbase, &kernbase_len, + NULL, 0) == -1) + warnx( + "WARNING: Could not retrieve kernel base address"); + else + start -= kernbase; + } +#endif + + /* + * Adjust the map entry to only cover the text portion + * of the object. + */ + + offset = start - image->pi_vaddr; + pcmnew->ppm_lowpc = image->pi_start + offset; + pcmnew->ppm_highpc = image->pi_end + offset; + pcmnew->ppm_image = image; + + assert(pcmnew->ppm_lowpc < pcmnew->ppm_highpc); + + /* Overlapped mmap()'s are assumed to never occur. */ + TAILQ_FOREACH(pcm, &pp->pp_map, ppm_next) + if (pcm->ppm_lowpc >= pcmnew->ppm_highpc) + break; + + if (pcm == NULL) + TAILQ_INSERT_TAIL(&pp->pp_map, pcmnew, ppm_next); + else + TAILQ_INSERT_BEFORE(pcm, pcmnew, ppm_next); +} + +/* + * Determine whether a given executable image is an A.OUT object, and + * if so, fill in its parameters from the text file. + * Sets image->pi_type. + */ + +void +pmcstat_image_get_aout_params(struct pmcstat_image *image, + struct pmcstat_args *args) +{ + int fd; + ssize_t nbytes; + struct exec ex; + const char *path; + char buffer[PATH_MAX]; + + path = pmcstat_string_unintern(image->pi_execpath); + assert(path != NULL); + + if (image->pi_iskernelmodule) + errx(EX_SOFTWARE, + "ERROR: a.out kernel modules are unsupported \"%s\"", path); + + (void) snprintf(buffer, sizeof(buffer), "%s%s", + args->pa_fsroot, path); + + if ((fd = open(buffer, O_RDONLY, 0)) < 0 || + (nbytes = read(fd, &ex, sizeof(ex))) < 0) { + if (args->pa_verbosity >= 2) + warn("WARNING: Cannot determine type of \"%s\"", + path); + image->pi_type = PMCSTAT_IMAGE_INDETERMINABLE; + if (fd != -1) + (void) close(fd); + return; + } + + (void) close(fd); + + if ((unsigned) nbytes != sizeof(ex) || + N_BADMAG(ex)) + return; + + image->pi_type = PMCSTAT_IMAGE_AOUT; + + /* TODO: the rest of a.out processing */ + + return; +} + +/* + * Examine an ELF file to determine the size of its text segment. + * Sets image->pi_type if anything conclusive can be determined about + * this image. + */ + +void +pmcstat_image_get_elf_params(struct pmcstat_image *image, + struct pmcstat_args *args) +{ + int fd; + size_t i, nph, nsh; + const char *path, *elfbase; + char *p, *endp; + bool first_exec_segment; + uintfptr_t minva, maxva; + Elf *e; + Elf_Scn *scn; + GElf_Ehdr eh; + GElf_Phdr ph; + GElf_Shdr sh; + enum pmcstat_image_type image_type; + char buffer[PATH_MAX]; + + assert(image->pi_type == PMCSTAT_IMAGE_UNKNOWN); + + image->pi_start = minva = ~(uintfptr_t) 0; + image->pi_end = maxva = (uintfptr_t) 0; + image->pi_type = image_type = PMCSTAT_IMAGE_INDETERMINABLE; + image->pi_isdynamic = 0; + image->pi_dynlinkerpath = NULL; + image->pi_vaddr = 0; + + path = pmcstat_string_unintern(image->pi_execpath); + assert(path != NULL); + + /* + * Look for files under FSROOT/PATHNAME. + */ + (void) snprintf(buffer, sizeof(buffer), "%s%s", + args->pa_fsroot, path); + + e = NULL; + fd = open(buffer, O_RDONLY, 0); + if (fd < 0) { + warnx("WARNING: Cannot open \"%s\".", + buffer); + goto done; + } + + if (elf_version(EV_CURRENT) == EV_NONE) { + warnx("WARNING: failed to init elf\n"); + goto done; + } + + if ((e = elf_begin(fd, ELF_C_READ, NULL)) == NULL) { + warnx("WARNING: Cannot read \"%s\".", + buffer); + goto done; + } + + if (elf_kind(e) != ELF_K_ELF) { + if (args->pa_verbosity >= 2) + warnx("WARNING: Cannot determine the type of \"%s\".", + buffer); + goto done; + } + + if (gelf_getehdr(e, &eh) != &eh) { + warnx( + "WARNING: Cannot retrieve the ELF Header for \"%s\": %s.", + buffer, elf_errmsg(-1)); + goto done; + } + + if (eh.e_type != ET_EXEC && eh.e_type != ET_DYN && + !(image->pi_iskernelmodule && eh.e_type == ET_REL)) { + warnx("WARNING: \"%s\" is of an unsupported ELF type.", + buffer); + goto done; + } + + image_type = eh.e_ident[EI_CLASS] == ELFCLASS32 ? + PMCSTAT_IMAGE_ELF32 : PMCSTAT_IMAGE_ELF64; + + /* + * Determine the virtual address where an executable would be + * loaded. Additionally, for dynamically linked executables, + * save the pathname to the runtime linker. + */ + if (eh.e_type != ET_REL) { + if (elf_getphnum(e, &nph) == 0) { + warnx( +"WARNING: Could not determine the number of program headers in \"%s\": %s.", + buffer, + elf_errmsg(-1)); + goto done; + } + first_exec_segment = true; + for (i = 0; i < eh.e_phnum; i++) { + if (gelf_getphdr(e, i, &ph) != &ph) { + warnx( +"WARNING: Retrieval of PHDR entry #%ju in \"%s\" failed: %s.", + (uintmax_t) i, buffer, elf_errmsg(-1)); + goto done; + } + switch (ph.p_type) { + case PT_DYNAMIC: + image->pi_isdynamic = 1; + break; + case PT_INTERP: + if ((elfbase = elf_rawfile(e, NULL)) == NULL) { + warnx( +"WARNING: Cannot retrieve the interpreter for \"%s\": %s.", + buffer, elf_errmsg(-1)); + goto done; + } + image->pi_dynlinkerpath = + pmcstat_string_intern(elfbase + + ph.p_offset); + break; + case PT_LOAD: + if ((ph.p_flags & PF_X) != 0 && + first_exec_segment) { + image->pi_vaddr = ph.p_vaddr & (-ph.p_align); + first_exec_segment = false; + } + break; + } + } + } + + /* + * Get the min and max VA associated with this ELF object. + */ + if (elf_getshnum(e, &nsh) == 0) { + warnx( +"WARNING: Could not determine the number of sections for \"%s\": %s.", + buffer, elf_errmsg(-1)); + goto done; + } + + for (i = 0; i < nsh; i++) { + if ((scn = elf_getscn(e, i)) == NULL || + gelf_getshdr(scn, &sh) != &sh) { + warnx( +"WARNING: Could not retrieve section header #%ju in \"%s\": %s.", + (uintmax_t) i, buffer, elf_errmsg(-1)); + goto done; + } + if (sh.sh_flags & SHF_EXECINSTR) { + minva = min(minva, sh.sh_addr); + maxva = max(maxva, sh.sh_addr + sh.sh_size); + } + if (sh.sh_type == SHT_SYMTAB || sh.sh_type == SHT_DYNSYM) + pmcstat_image_add_symbols(image, e, scn, &sh); + } + + image->pi_start = minva; + image->pi_end = maxva; + image->pi_type = image_type; + image->pi_fullpath = pmcstat_string_intern(buffer); + + /* Build display name + */ + endp = buffer; + for (p = buffer; *p; p++) + if (*p == '/') + endp = p+1; + image->pi_name = pmcstat_string_intern(endp); + + done: + (void) elf_end(e); + if (fd >= 0) + (void) close(fd); + return; +} + +/* + * Given an image descriptor, determine whether it is an ELF, or AOUT. + * If no handler claims the image, set its type to 'INDETERMINABLE'. + */ + +void +pmcstat_image_determine_type(struct pmcstat_image *image, + struct pmcstat_args *args) +{ + assert(image->pi_type == PMCSTAT_IMAGE_UNKNOWN); + + /* Try each kind of handler in turn */ + if (image->pi_type == PMCSTAT_IMAGE_UNKNOWN) + pmcstat_image_get_elf_params(image, args); + if (image->pi_type == PMCSTAT_IMAGE_UNKNOWN) + pmcstat_image_get_aout_params(image, args); + + /* + * Otherwise, remember that we tried to determine + * the object's type and had failed. + */ + if (image->pi_type == PMCSTAT_IMAGE_UNKNOWN) + image->pi_type = PMCSTAT_IMAGE_INDETERMINABLE; +} + +/* + * Locate an image descriptor given an interned path, adding a fresh + * descriptor to the cache if necessary. This function also finds a + * suitable name for this image's sample file. + * + * We defer filling in the file format specific parts of the image + * structure till the time we actually see a sample that would fall + * into this image. + */ + +struct pmcstat_image * +pmcstat_image_from_path(pmcstat_interned_string internedpath, + int iskernelmodule, struct pmcstat_args *args, + struct pmc_plugins *plugins) +{ + int hash; + struct pmcstat_image *pi; + + hash = pmcstat_string_lookup_hash(internedpath); + + /* First, look for an existing entry. */ + LIST_FOREACH(pi, &pmcstat_image_hash[hash], pi_next) + if (pi->pi_execpath == internedpath && + pi->pi_iskernelmodule == iskernelmodule) + return (pi); + + /* + * Allocate a new entry and place it at the head of the hash + * and LRU lists. + */ + pi = malloc(sizeof(*pi)); + if (pi == NULL) + return (NULL); + + pi->pi_type = PMCSTAT_IMAGE_UNKNOWN; + pi->pi_execpath = internedpath; + pi->pi_start = ~0; + pi->pi_end = 0; + pi->pi_entry = 0; + pi->pi_vaddr = 0; + pi->pi_isdynamic = 0; + pi->pi_iskernelmodule = iskernelmodule; + pi->pi_dynlinkerpath = NULL; + pi->pi_symbols = NULL; + pi->pi_symcount = 0; + pi->pi_addr2line = NULL; + + if (plugins[args->pa_pplugin].pl_initimage != NULL) + plugins[args->pa_pplugin].pl_initimage(pi); + if (plugins[args->pa_plugin].pl_initimage != NULL) + plugins[args->pa_plugin].pl_initimage(pi); + + LIST_INSERT_HEAD(&pmcstat_image_hash[hash], pi, pi_next); + + return (pi); +} |