diff options
Diffstat (limited to 'scripts/recordmcount.c')
| -rw-r--r-- | scripts/recordmcount.c | 885 |
1 files changed, 885 insertions, 0 deletions
diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c new file mode 100644 index 00000000000..34f32be1709 --- /dev/null +++ b/scripts/recordmcount.c @@ -0,0 +1,885 @@ +/* + * recordmcount.c: construct a table of the locations of calls to 'mcount' + * so that ftrace can find them quickly. + * Copyright 2009 John F. Reiser <jreiser@BitWagon.com>. All rights reserved. + * Licensed under the GNU General Public License, version 2 (GPLv2). + * + * Restructured to fit Linux format, as well as other updates: + * Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc. + */ + +/* + * Strategy: alter the .o file in-place. + * + * Append a new STRTAB that has the new section names, followed by a new array + * ElfXX_Shdr[] that has the new section headers, followed by the section + * contents for __mcount_loc and its relocations. The old shstrtab strings, + * and the old ElfXX_Shdr[] array, remain as "garbage" (commonly, a couple + * kilobytes.) Subsequent processing by /bin/ld (or the kernel module loader) + * will ignore the garbage regions, because they are not designated by the + * new .e_shoff nor the new ElfXX_Shdr[]. [In order to remove the garbage, + * then use "ld -r" to create a new file that omits the garbage.] + */ + +#include <sys/types.h> +#include <sys/mman.h> +#include <sys/stat.h> +#include <elf.h> +#include <fcntl.h> +#include <setjmp.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +static int fd_map; /* File descriptor for file being modified. */ +static int mmap_failed; /* Boolean flag. */ +static void *ehdr_curr; /* current ElfXX_Ehdr * for resource cleanup */ +static char gpfx; /* prefix for global symbol name (sometimes '_') */ +static struct stat sb; /* Remember .st_size, etc. */ +static jmp_buf jmpenv; /* setjmp/longjmp per-file error escape */ + +/* setjmp() return values */ +enum { + SJ_SETJMP = 0, /* hardwired first return */ + SJ_FAIL, + SJ_SUCCEED +}; + +/* Per-file resource cleanup when multiple files. */ +static void +cleanup(void) +{ + if (!mmap_failed) + munmap(ehdr_curr, sb.st_size); + else + free(ehdr_curr); + close(fd_map); +} + +static void __attribute__((noreturn)) +fail_file(void) +{ + cleanup(); + longjmp(jmpenv, SJ_FAIL); +} + +static void __attribute__((noreturn)) +succeed_file(void) +{ + cleanup(); + longjmp(jmpenv, SJ_SUCCEED); +} + +/* ulseek, uread, ...: Check return value for errors. */ + +static off_t +ulseek(int const fd, off_t const offset, int const whence) +{ + off_t const w = lseek(fd, offset, whence); + if ((off_t)-1 == w) { + perror("lseek"); + fail_file(); + } + return w; +} + +static size_t +uread(int const fd, void *const buf, size_t const count) +{ + size_t const n = read(fd, buf, count); + if (n != count) { + perror("read"); + fail_file(); + } + return n; +} + +static size_t +uwrite(int const fd, void const *const buf, size_t const count) +{ + size_t const n = write(fd, buf, count); + if (n != count) { + perror("write"); + fail_file(); + } + return n; +} + +static void * +umalloc(size_t size) +{ + void *const addr = malloc(size); + if (0 == addr) { + fprintf(stderr, "malloc failed: %zu bytes\n", size); + fail_file(); + } + return addr; +} + +/* + * Get the whole file as a programming convenience in order to avoid + * malloc+lseek+read+free of many pieces. If successful, then mmap + * avoids copying unused pieces; else just read the whole file. + * Open for both read and write; new info will be appended to the file. + * Use MAP_PRIVATE so that a few changes to the in-memory ElfXX_Ehdr + * do not propagate to the file until an explicit overwrite at the last. + * This preserves most aspects of consistency (all except .st_size) + * for simultaneous readers of the file while we are appending to it. + * However, multiple writers still are bad. We choose not to use + * locking because it is expensive and the use case of kernel build + * makes multiple writers unlikely. + */ +static void *mmap_file(char const *fname) +{ + void *addr; + + fd_map = open(fname, O_RDWR); + if (0 > fd_map || 0 > fstat(fd_map, &sb)) { + perror(fname); + fail_file(); + } + if (!S_ISREG(sb.st_mode)) { + fprintf(stderr, "not a regular file: %s\n", fname); + fail_file(); + } + addr = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_PRIVATE, + fd_map, 0); + mmap_failed = 0; + if (MAP_FAILED == addr) { + mmap_failed = 1; + addr = umalloc(sb.st_size); + uread(fd_map, addr, sb.st_size); + } + return addr; +} + +/* w8rev, w8nat, ...: Handle endianness. */ + +static uint64_t w8rev(uint64_t const x) +{ + return ((0xff & (x >> (0 * 8))) << (7 * 8)) + | ((0xff & (x >> (1 * 8))) << (6 * 8)) + | ((0xff & (x >> (2 * 8))) << (5 * 8)) + | ((0xff & (x >> (3 * 8))) << (4 * 8)) + | ((0xff & (x >> (4 * 8))) << (3 * 8)) + | ((0xff & (x >> (5 * 8))) << (2 * 8)) + | ((0xff & (x >> (6 * 8))) << (1 * 8)) + | ((0xff & (x >> (7 * 8))) << (0 * 8)); +} + +static uint32_t w4rev(uint32_t const x) +{ + return ((0xff & (x >> (0 * 8))) << (3 * 8)) + | ((0xff & (x >> (1 * 8))) << (2 * 8)) + | ((0xff & (x >> (2 * 8))) << (1 * 8)) + | ((0xff & (x >> (3 * 8))) << (0 * 8)); +} + +static uint32_t w2rev(uint16_t const x) +{ + return ((0xff & (x >> (0 * 8))) << (1 * 8)) + | ((0xff & (x >> (1 * 8))) << (0 * 8)); +} + +static uint64_t w8nat(uint64_t const x) +{ + return x; +} + +static uint32_t w4nat(uint32_t const x) +{ + return x; +} + +static uint32_t w2nat(uint16_t const x) +{ + return x; +} + +static uint64_t (*w8)(uint64_t); +static uint32_t (*w)(uint32_t); +static uint32_t (*w2)(uint16_t); + +/* Names of the sections that could contain calls to mcount. */ +static int +is_mcounted_section_name(char const *const txtname) +{ + return 0 == strcmp(".text", txtname) || + 0 == strcmp(".sched.text", txtname) || + 0 == strcmp(".spinlock.text", txtname) || + 0 == strcmp(".irqentry.text", txtname) || + 0 == strcmp(".text.unlikely", txtname); +} + +/* Append the new shstrtab, Elf32_Shdr[], __mcount_loc and its relocations. */ +static void append32(Elf32_Ehdr *const ehdr, + Elf32_Shdr *const shstr, + uint32_t const *const mloc0, + uint32_t const *const mlocp, + Elf32_Rel const *const mrel0, + Elf32_Rel const *const mrelp, + unsigned int const rel_entsize, + unsigned int const symsec_sh_link) +{ + /* Begin constructing output file */ + Elf32_Shdr mcsec; + char const *mc_name = (sizeof(Elf32_Rela) == rel_entsize) + ? ".rela__mcount_loc" + : ".rel__mcount_loc"; + unsigned const old_shnum = w2(ehdr->e_shnum); + uint32_t const old_shoff = w(ehdr->e_shoff); + uint32_t const old_shstr_sh_size = w(shstr->sh_size); + uint32_t const old_shstr_sh_offset = w(shstr->sh_offset); + uint32_t t = 1 + strlen(mc_name) + w(shstr->sh_size); + uint32_t new_e_shoff; + + shstr->sh_size = w(t); + shstr->sh_offset = w(sb.st_size); + t += sb.st_size; + t += (3u & -t); /* 4-byte align */ + new_e_shoff = t; + + /* body for new shstrtab */ + ulseek(fd_map, sb.st_size, SEEK_SET); + uwrite(fd_map, old_shstr_sh_offset + (void *)ehdr, old_shstr_sh_size); + uwrite(fd_map, mc_name, 1 + strlen(mc_name)); + + /* old(modified) Elf32_Shdr table, 4-byte aligned */ + ulseek(fd_map, t, SEEK_SET); + t += sizeof(Elf32_Shdr) * old_shnum; + uwrite(fd_map, old_shoff + (void *)ehdr, + sizeof(Elf32_Shdr) * old_shnum); + + /* new sections __mcount_loc and .rel__mcount_loc */ + t += 2*sizeof(mcsec); + mcsec.sh_name = w((sizeof(Elf32_Rela) == rel_entsize) + strlen(".rel") + + old_shstr_sh_size); + mcsec.sh_type = w(SHT_PROGBITS); + mcsec.sh_flags = w(SHF_ALLOC); + mcsec.sh_addr = 0; + mcsec.sh_offset = w(t); + mcsec.sh_size = w((void *)mlocp - (void *)mloc0); + mcsec.sh_link = 0; + mcsec.sh_info = 0; + mcsec.sh_addralign = w(4); + mcsec.sh_entsize = w(4); + uwrite(fd_map, &mcsec, sizeof(mcsec)); + + mcsec.sh_name = w(old_shstr_sh_size); + mcsec.sh_type = (sizeof(Elf32_Rela) == rel_entsize) + ? w(SHT_RELA) + : w(SHT_REL); + mcsec.sh_flags = 0; + mcsec.sh_addr = 0; + mcsec.sh_offset = w((void *)mlocp - (void *)mloc0 + t); + mcsec.sh_size = w((void *)mrelp - (void *)mrel0); + mcsec.sh_link = w(symsec_sh_link); + mcsec.sh_info = w(old_shnum); + mcsec.sh_addralign = w(4); + mcsec.sh_entsize = w(rel_entsize); + uwrite(fd_map, &mcsec, sizeof(mcsec)); + + uwrite(fd_map, mloc0, (void *)mlocp - (void *)mloc0); + uwrite(fd_map, mrel0, (void *)mrelp - (void *)mrel0); + + ehdr->e_shoff = w(new_e_shoff); + ehdr->e_shnum = w2(2 + w2(ehdr->e_shnum)); /* {.rel,}__mcount_loc */ + ulseek(fd_map, 0, SEEK_SET); + uwrite(fd_map, ehdr, sizeof(*ehdr)); +} + +/* + * append64 and append32 (and other analogous pairs) could be templated + * using C++, but the complexity is high. (For an example, look at p_elf.h + * in the source for UPX, http://upx.sourceforge.net) So: remember to make + * the corresponding change in the routine for the other size. + */ +static void append64(Elf64_Ehdr *const ehdr, + Elf64_Shdr *const shstr, + uint64_t const *const mloc0, + uint64_t const *const mlocp, + Elf64_Rel const *const mrel0, + Elf64_Rel const *const mrelp, + unsigned int const rel_entsize, + unsigned int const symsec_sh_link) +{ + /* Begin constructing output file */ + Elf64_Shdr mcsec; + char const *mc_name = (sizeof(Elf64_Rela) == rel_entsize) + ? ".rela__mcount_loc" + : ".rel__mcount_loc"; + unsigned const old_shnum = w2(ehdr->e_shnum); + uint64_t const old_shoff = w8(ehdr->e_shoff); + uint64_t const old_shstr_sh_size = w8(shstr->sh_size); + uint64_t const old_shstr_sh_offset = w8(shstr->sh_offset); + uint64_t t = 1 + strlen(mc_name) + w8(shstr->sh_size); + uint64_t new_e_shoff; + + shstr->sh_size = w8(t); + shstr->sh_offset = w8(sb.st_size); + t += sb.st_size; + t += (7u & -t); /* 8-byte align */ + new_e_shoff = t; + + /* body for new shstrtab */ + ulseek(fd_map, sb.st_size, SEEK_SET); + uwrite(fd_map, old_shstr_sh_offset + (void *)ehdr, old_shstr_sh_size); + uwrite(fd_map, mc_name, 1 + strlen(mc_name)); + + /* old(modified) Elf64_Shdr table, 8-byte aligned */ + ulseek(fd_map, t, SEEK_SET); + t += sizeof(Elf64_Shdr) * old_shnum; + uwrite(fd_map, old_shoff + (void *)ehdr, + sizeof(Elf64_Shdr) * old_shnum); + + /* new sections __mcount_loc and .rel__mcount_loc */ + t += 2*sizeof(mcsec); + mcsec.sh_name = w((sizeof(Elf64_Rela) == rel_entsize) + strlen(".rel") + + old_shstr_sh_size); + mcsec.sh_type = w(SHT_PROGBITS); + mcsec.sh_flags = w8(SHF_ALLOC); + mcsec.sh_addr = 0; + mcsec.sh_offset = w8(t); + mcsec.sh_size = w8((void *)mlocp - (void *)mloc0); + mcsec.sh_link = 0; + mcsec.sh_info = 0; + mcsec.sh_addralign = w8(8); + mcsec.sh_entsize = w8(8); + uwrite(fd_map, &mcsec, sizeof(mcsec)); + + mcsec.sh_name = w(old_shstr_sh_size); + mcsec.sh_type = (sizeof(Elf64_Rela) == rel_entsize) + ? w(SHT_RELA) + : w(SHT_REL); + mcsec.sh_flags = 0; + mcsec.sh_addr = 0; + mcsec.sh_offset = w8((void *)mlocp - (void *)mloc0 + t); + mcsec.sh_size = w8((void *)mrelp - (void *)mrel0); + mcsec.sh_link = w(symsec_sh_link); + mcsec.sh_info = w(old_shnum); + mcsec.sh_addralign = w8(8); + mcsec.sh_entsize = w8(rel_entsize); + uwrite(fd_map, &mcsec, sizeof(mcsec)); + + uwrite(fd_map, mloc0, (void *)mlocp - (void *)mloc0); + uwrite(fd_map, mrel0, (void *)mrelp - (void *)mrel0); + + ehdr->e_shoff = w8(new_e_shoff); + ehdr->e_shnum = w2(2 + w2(ehdr->e_shnum)); /* {.rel,}__mcount_loc */ + ulseek(fd_map, 0, SEEK_SET); + uwrite(fd_map, ehdr, sizeof(*ehdr)); +} + +/* + * Look at the relocations in order to find the calls to mcount. + * Accumulate the section offsets that are found, and their relocation info, + * onto the end of the existing arrays. + */ +static uint32_t *sift32_rel_mcount(uint32_t *mlocp, + unsigned const offbase, + Elf32_Rel **const mrelpp, + Elf32_Shdr const *const relhdr, + Elf32_Ehdr const *const ehdr, + unsigned const recsym, + uint32_t const recval, + unsigned const reltype) +{ + uint32_t *const mloc0 = mlocp; + Elf32_Rel *mrelp = *mrelpp; + Elf32_Shdr *const shdr0 = (Elf32_Shdr *)(w(ehdr->e_shoff) + + (void *)ehdr); + unsigned const symsec_sh_link = w(relhdr->sh_link); + Elf32_Shdr const *const symsec = &shdr0[symsec_sh_link]; + Elf32_Sym const *const sym0 = (Elf32_Sym const *)(w(symsec->sh_offset) + + (void *)ehdr); + + Elf32_Shdr const *const strsec = &shdr0[w(symsec->sh_link)]; + char const *const str0 = (char const *)(w(strsec->sh_offset) + + (void *)ehdr); + + Elf32_Rel const *const rel0 = (Elf32_Rel const *)(w(relhdr->sh_offset) + + (void *)ehdr); + unsigned rel_entsize = w(relhdr->sh_entsize); + unsigned const nrel = w(relhdr->sh_size) / rel_entsize; + Elf32_Rel const *relp = rel0; + + unsigned mcountsym = 0; + unsigned t; + + for (t = nrel; t; --t) { + if (!mcountsym) { + Elf32_Sym const *const symp = + &sym0[ELF32_R_SYM(w(relp->r_info))]; + + if (0 == strcmp((('_' == gpfx) ? "_mcount" : "mcount"), + &str0[w(symp->st_name)])) + mcountsym = ELF32_R_SYM(w(relp->r_info)); + } + if (mcountsym == ELF32_R_SYM(w(relp->r_info))) { + uint32_t const addend = w(w(relp->r_offset) - recval); + mrelp->r_offset = w(offbase + + ((void *)mlocp - (void *)mloc0)); + mrelp->r_info = w(ELF32_R_INFO(recsym, reltype)); + if (sizeof(Elf32_Rela) == rel_entsize) { + ((Elf32_Rela *)mrelp)->r_addend = addend; + *mlocp++ = 0; + } else + *mlocp++ = addend; + + mrelp = (Elf32_Rel *)(rel_entsize + (void *)mrelp); + } + relp = (Elf32_Rel const *)(rel_entsize + (void *)relp); + } + *mrelpp = mrelp; + return mlocp; +} + +static uint64_t *sift64_rel_mcount(uint64_t *mlocp, + unsigned const offbase, + Elf64_Rel **const mrelpp, + Elf64_Shdr const *const relhdr, + Elf64_Ehdr const *const ehdr, + unsigned const recsym, + uint64_t const recval, + unsigned const reltype) +{ + uint64_t *const mloc0 = mlocp; + Elf64_Rel *mrelp = *mrelpp; + Elf64_Shdr *const shdr0 = (Elf64_Shdr *)(w8(ehdr->e_shoff) + + (void *)ehdr); + unsigned const symsec_sh_link = w(relhdr->sh_link); + Elf64_Shdr const *const symsec = &shdr0[symsec_sh_link]; + Elf64_Sym const *const sym0 = (Elf64_Sym const *)(w8(symsec->sh_offset) + + (void *)ehdr); + + Elf64_Shdr const *const strsec = &shdr0[w(symsec->sh_link)]; + char const *const str0 = (char const *)(w8(strsec->sh_offset) + + (void *)ehdr); + + Elf64_Rel const *const rel0 = (Elf64_Rel const *)(w8(relhdr->sh_offset) + + (void *)ehdr); + unsigned rel_entsize = w8(relhdr->sh_entsize); + unsigned const nrel = w8(relhdr->sh_size) / rel_entsize; + Elf64_Rel const *relp = rel0; + + unsigned mcountsym = 0; + unsigned t; + + for (t = nrel; 0 != t; --t) { + if (!mcountsym) { + Elf64_Sym const *const symp = + &sym0[ELF64_R_SYM(w8(relp->r_info))]; + char const *symname = &str0[w(symp->st_name)]; + + if ('.' == symname[0]) + ++symname; /* ppc64 hack */ + if (0 == strcmp((('_' == gpfx) ? "_mcount" : "mcount"), + symname)) + mcountsym = ELF64_R_SYM(w8(relp->r_info)); + } + + if (mcountsym == ELF64_R_SYM(w8(relp->r_info))) { + uint64_t const addend = w8(w8(relp->r_offset) - recval); + + mrelp->r_offset = w8(offbase + + ((void *)mlocp - (void *)mloc0)); + mrelp->r_info = w8(ELF64_R_INFO(recsym, reltype)); + if (sizeof(Elf64_Rela) == rel_entsize) { + ((Elf64_Rela *)mrelp)->r_addend = addend; + *mlocp++ = 0; + } else + *mlocp++ = addend; + + mrelp = (Elf64_Rel *)(rel_entsize + (void *)mrelp); + } + relp = (Elf64_Rel const *)(rel_entsize + (void *)relp); + } + *mrelpp = mrelp; + + return mlocp; +} + +/* + * Find a symbol in the given section, to be used as the base for relocating + * the table of offsets of calls to mcount. A local or global symbol suffices, + * but avoid a Weak symbol because it may be overridden; the change in value + * would invalidate the relocations of the offsets of the calls to mcount. + * Often the found symbol will be the unnamed local symbol generated by + * GNU 'as' for the start of each section. For example: + * Num: Value Size Type Bind Vis Ndx Name + * 2: 00000000 0 SECTION LOCAL DEFAULT 1 + */ +static unsigned find32_secsym_ndx(unsigned const txtndx, + char const *const txtname, + uint32_t *const recvalp, + Elf32_Shdr const *const symhdr, + Elf32_Ehdr const *const ehdr) +{ + Elf32_Sym const *const sym0 = (Elf32_Sym const *)(w(symhdr->sh_offset) + + (void *)ehdr); + unsigned const nsym = w(symhdr->sh_size) / w(symhdr->sh_entsize); + Elf32_Sym const *symp; + unsigned t; + + for (symp = sym0, t = nsym; t; --t, ++symp) { + unsigned int const st_bind = ELF32_ST_BIND(symp->st_info); + + if (txtndx == w2(symp->st_shndx) + /* avoid STB_WEAK */ + && (STB_LOCAL == st_bind || STB_GLOBAL == st_bind)) { + *recvalp = w(symp->st_value); + return symp - sym0; + } + } + fprintf(stderr, "Cannot find symbol for section %d: %s.\n", + txtndx, txtname); + fail_file(); +} + +static unsigned find64_secsym_ndx(unsigned const txtndx, + char const *const txtname, + uint64_t *const recvalp, + Elf64_Shdr const *const symhdr, + Elf64_Ehdr const *const ehdr) +{ + Elf64_Sym const *const sym0 = (Elf64_Sym const *)(w8(symhdr->sh_offset) + + (void *)ehdr); + unsigned const nsym = w8(symhdr->sh_size) / w8(symhdr->sh_entsize); + Elf64_Sym const *symp; + unsigned t; + + for (symp = sym0, t = nsym; t; --t, ++symp) { + unsigned int const st_bind = ELF64_ST_BIND(symp->st_info); + + if (txtndx == w2(symp->st_shndx) + /* avoid STB_WEAK */ + && (STB_LOCAL == st_bind || STB_GLOBAL == st_bind)) { + *recvalp = w8(symp->st_value); + return symp - sym0; + } + } + fprintf(stderr, "Cannot find symbol for section %d: %s.\n", + txtndx, txtname); + fail_file(); +} + +/* + * Evade ISO C restriction: no declaration after statement in + * has32_rel_mcount. + */ +static char const * +__has32_rel_mcount(Elf32_Shdr const *const relhdr, /* is SHT_REL or SHT_RELA */ + Elf32_Shdr const *const shdr0, + char const *const shstrtab, + char const *const fname) +{ + /* .sh_info depends on .sh_type == SHT_REL[,A] */ + Elf32_Shdr const *const txthdr = &shdr0[w(relhdr->sh_info)]; + char const *const txtname = &shstrtab[w(txthdr->sh_name)]; + + if (0 == strcmp("__mcount_loc", txtname)) { + fprintf(stderr, "warning: __mcount_loc already exists: %s\n", + fname); + succeed_file(); + } + if (SHT_PROGBITS != w(txthdr->sh_type) || + !is_mcounted_section_name(txtname)) + return NULL; + return txtname; +} + +static char const *has32_rel_mcount(Elf32_Shdr const *const relhdr, + Elf32_Shdr const *const shdr0, + char const *const shstrtab, + char const *const fname) +{ + if (SHT_REL != w(relhdr->sh_type) && SHT_RELA != w(relhdr->sh_type)) + return NULL; + return __has32_rel_mcount(relhdr, shdr0, shstrtab, fname); +} + +static char const *__has64_rel_mcount(Elf64_Shdr const *const relhdr, + Elf64_Shdr const *const shdr0, + char const *const shstrtab, + char const *const fname) +{ + /* .sh_info depends on .sh_type == SHT_REL[,A] */ + Elf64_Shdr const *const txthdr = &shdr0[w(relhdr->sh_info)]; + char const *const txtname = &shstrtab[w(txthdr->sh_name)]; + + if (0 == strcmp("__mcount_loc", txtname)) { + fprintf(stderr, "warning: __mcount_loc already exists: %s\n", + fname); + succeed_file(); + } + if (SHT_PROGBITS != w(txthdr->sh_type) || + !is_mcounted_section_name(txtname)) + return NULL; + return txtname; +} + +static char const *has64_rel_mcount(Elf64_Shdr const *const relhdr, + Elf64_Shdr const *const shdr0, + char const *const shstrtab, + char const *const fname) +{ + if (SHT_REL != w(relhdr->sh_type) && SHT_RELA != w(relhdr->sh_type)) + return NULL; + return __has64_rel_mcount(relhdr, shdr0, shstrtab, fname); +} + +static unsigned tot32_relsize(Elf32_Shdr const *const shdr0, + unsigned nhdr, + const char *const shstrtab, + const char *const fname) +{ + unsigned totrelsz = 0; + Elf32_Shdr const *shdrp = shdr0; + for (; 0 != nhdr; --nhdr, ++shdrp) { + if (has32_rel_mcount(shdrp, shdr0, shstrtab, fname)) + totrelsz += w(shdrp->sh_size); + } + return totrelsz; +} + +static unsigned tot64_relsize(Elf64_Shdr const *const shdr0, + unsigned nhdr, + const char *const shstrtab, + const char *const fname) +{ + unsigned totrelsz = 0; + Elf64_Shdr const *shdrp = shdr0; + + for (; nhdr; --nhdr, ++shdrp) { + if (has64_rel_mcount(shdrp, shdr0, shstrtab, fname)) + totrelsz += w8(shdrp->sh_size); + } + return totrelsz; +} + +/* Overall supervision for Elf32 ET_REL file. */ +static void +do32(Elf32_Ehdr *const ehdr, char const *const fname, unsigned const reltype) +{ + Elf32_Shdr *const shdr0 = (Elf32_Shdr *)(w(ehdr->e_shoff) + + (void *)ehdr); + unsigned const nhdr = w2(ehdr->e_shnum); + Elf32_Shdr *const shstr = &shdr0[w2(ehdr->e_shstrndx)]; + char const *const shstrtab = (char const *)(w(shstr->sh_offset) + + (void *)ehdr); + + Elf32_Shdr const *relhdr; + unsigned k; + + /* Upper bound on space: assume all relevant relocs are for mcount. */ + unsigned const totrelsz = tot32_relsize(shdr0, nhdr, shstrtab, fname); + Elf32_Rel *const mrel0 = umalloc(totrelsz); + Elf32_Rel * mrelp = mrel0; + + /* 2*sizeof(address) <= sizeof(Elf32_Rel) */ + uint32_t *const mloc0 = umalloc(totrelsz>>1); + uint32_t * mlocp = mloc0; + + unsigned rel_entsize = 0; + unsigned symsec_sh_link = 0; + + for (relhdr = shdr0, k = nhdr; k; --k, ++relhdr) { + char const *const txtname = has32_rel_mcount(relhdr, shdr0, + shstrtab, fname); + if (txtname) { + uint32_t recval = 0; + unsigned const recsym = find32_secsym_ndx( + w(relhdr->sh_info), txtname, &recval, + &shdr0[symsec_sh_link = w(relhdr->sh_link)], + ehdr); + + rel_entsize = w(relhdr->sh_entsize); + mlocp = sift32_rel_mcount(mlocp, + (void *)mlocp - (void *)mloc0, &mrelp, + relhdr, ehdr, recsym, recval, reltype); + } + } + if (mloc0 != mlocp) { + append32(ehdr, shstr, mloc0, mlocp, mrel0, mrelp, + rel_entsize, symsec_sh_link); + } + free(mrel0); + free(mloc0); +} + +static void +do64(Elf64_Ehdr *const ehdr, char const *const fname, unsigned const reltype) +{ + Elf64_Shdr *const shdr0 = (Elf64_Shdr *)(w8(ehdr->e_shoff) + + (void *)ehdr); + unsigned const nhdr = w2(ehdr->e_shnum); + Elf64_Shdr *const shstr = &shdr0[w2(ehdr->e_shstrndx)]; + char const *const shstrtab = (char const *)(w8(shstr->sh_offset) + + (void *)ehdr); + + Elf64_Shdr const *relhdr; + unsigned k; + + /* Upper bound on space: assume all relevant relocs are for mcount. */ + unsigned const totrelsz = tot64_relsize(shdr0, nhdr, shstrtab, fname); + Elf64_Rel *const mrel0 = umalloc(totrelsz); + Elf64_Rel * mrelp = mrel0; + + /* 2*sizeof(address) <= sizeof(Elf64_Rel) */ + uint64_t *const mloc0 = umalloc(totrelsz>>1); + uint64_t * mlocp = mloc0; + + unsigned rel_entsize = 0; + unsigned symsec_sh_link = 0; + + for ((relhdr = shdr0), k = nhdr; k; --k, ++relhdr) { + char const *const txtname = has64_rel_mcount(relhdr, shdr0, + shstrtab, fname); + if (txtname) { + uint64_t recval = 0; + unsigned const recsym = find64_secsym_ndx( + w(relhdr->sh_info), txtname, &recval, + &shdr0[symsec_sh_link = w(relhdr->sh_link)], + ehdr); + + rel_entsize = w8(relhdr->sh_entsize); + mlocp = sift64_rel_mcount(mlocp, + (void *)mlocp - (void *)mloc0, &mrelp, + relhdr, ehdr, recsym, recval, reltype); + } + } + if (mloc0 != mlocp) { + append64(ehdr, shstr, mloc0, mlocp, mrel0, mrelp, + rel_entsize, symsec_sh_link); + } + free(mrel0); + free(mloc0); +} + +static void +do_file(char const *const fname) +{ + Elf32_Ehdr *const ehdr = mmap_file(fname); + unsigned int reltype = 0; + + ehdr_curr = ehdr; + w = w4nat; + w2 = w2nat; + w8 = w8nat; + switch (ehdr->e_ident[EI_DATA]) { + static unsigned int const endian = 1; + default: { + fprintf(stderr, "unrecognized ELF data encoding %d: %s\n", + ehdr->e_ident[EI_DATA], fname); + fail_file(); + } break; + case ELFDATA2LSB: { + if (1 != *(unsigned char const *)&endian) { + /* main() is big endian, file.o is little endian. */ + w = w4rev; + w2 = w2rev; + w8 = w8rev; + } + } break; + case ELFDATA2MSB: { + if (0 != *(unsigned char const *)&endian) { + /* main() is little endian, file.o is big endian. */ + w = w4rev; + w2 = w2rev; + w8 = w8rev; + } + } break; + } /* end switch */ + if (0 != memcmp(ELFMAG, ehdr->e_ident, SELFMAG) + || ET_REL != w2(ehdr->e_type) + || EV_CURRENT != ehdr->e_ident[EI_VERSION]) { + fprintf(stderr, "unrecognized ET_REL file %s\n", fname); + fail_file(); + } + + gpfx = 0; + switch (w2(ehdr->e_machine)) { + default: { + fprintf(stderr, "unrecognized e_machine %d %s\n", + w2(ehdr->e_machine), fname); + fail_file(); + } break; + case EM_386: reltype = R_386_32; break; + case EM_ARM: reltype = R_ARM_ABS32; break; + case EM_IA_64: reltype = R_IA64_IMM64; gpfx = '_'; break; + case EM_PPC: reltype = R_PPC_ADDR32; gpfx = '_'; break; + case EM_PPC64: reltype = R_PPC64_ADDR64; gpfx = '_'; break; + case EM_S390: /* reltype: e_class */ gpfx = '_'; break; + case EM_SH: reltype = R_SH_DIR32; break; + case EM_SPARCV9: reltype = R_SPARC_64; gpfx = '_'; break; + case EM_X86_64: reltype = R_X86_64_64; break; + } /* end switch */ + + switch (ehdr->e_ident[EI_CLASS]) { + default: { + fprintf(stderr, "unrecognized ELF class %d %s\n", + ehdr->e_ident[EI_CLASS], fname); + fail_file(); + } break; + case ELFCLASS32: { + if (sizeof(Elf32_Ehdr) != w2(ehdr->e_ehsize) + || sizeof(Elf32_Shdr) != w2(ehdr->e_shentsize)) { + fprintf(stderr, + "unrecognized ET_REL file: %s\n", fname); + fail_file(); + } + if (EM_S390 == w2(ehdr->e_machine)) + reltype = R_390_32; + do32(ehdr, fname, reltype); + } break; + case ELFCLASS64: { + Elf64_Ehdr *const ghdr = (Elf64_Ehdr *)ehdr; + if (sizeof(Elf64_Ehdr) != w2(ghdr->e_ehsize) + || sizeof(Elf64_Shdr) != w2(ghdr->e_shentsize)) { + fprintf(stderr, + "unrecognized ET_REL file: %s\n", fname); + fail_file(); + } + if (EM_S390 == w2(ghdr->e_machine)) + reltype = R_390_64; + do64(ghdr, fname, reltype); + } break; + } /* end switch */ + + cleanup(); +} + +int +main(int argc, char const *argv[]) +{ + int n_error = 0; /* gcc-4.3.0 false positive complaint */ + if (argc <= 1) + fprintf(stderr, "usage: recordmcount file.o...\n"); + else /* Process each file in turn, allowing deep failure. */ + for (--argc, ++argv; 0 < argc; --argc, ++argv) { + int const sjval = setjmp(jmpenv); + switch (sjval) { + default: { + fprintf(stderr, "internal error: %s\n", argv[0]); + exit(1); + } break; + case SJ_SETJMP: { /* normal sequence */ + /* Avoid problems if early cleanup() */ + fd_map = -1; + ehdr_curr = NULL; + mmap_failed = 1; + do_file(argv[0]); + } break; + case SJ_FAIL: { /* error in do_file or below */ + ++n_error; + } break; + case SJ_SUCCEED: { /* premature success */ + /* do nothing */ + } break; + } /* end switch */ + } + return !!n_error; +} + + |