/* * recordmcount.c: construct a table of the locations of calls to 'mcount' * so that ftrace can find them quickly. * Copyright 2009 John F. Reiser . 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 , 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 #include #include #include #include #include #include #include #include #include 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; }