| |
| /*--------------------------------------------------------------------*/ |
| /*--- User-mode execve(), and other stuff shared between stage1 ---*/ |
| /*--- and stage2. m_ume.c ---*/ |
| /*--------------------------------------------------------------------*/ |
| |
| /* |
| This file is part of Valgrind, a dynamic binary instrumentation |
| framework. |
| |
| Copyright (C) 2000-2005 Julian Seward |
| jseward@acm.org |
| |
| This program is free software; you can redistribute it and/or |
| modify it under the terms of the GNU General Public License as |
| published by the Free Software Foundation; either version 2 of the |
| License, or (at your option) any later version. |
| |
| This program 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 |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program; if not, write to the Free Software |
| Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307, USA. |
| |
| The GNU General Public License is contained in the file COPYING. |
| */ |
| |
| |
| #define _GNU_SOURCE |
| #define _FILE_OFFSET_BITS 64 |
| |
| // It seems that on SuSE 9.1 (x86) something in <fcntl.h> messes up stuff |
| // acquired indirectly from vki-x86-linux.h. Therefore our headers must be |
| // included ahead of the glibc ones. This fix is a kludge; the right |
| // solution is to entirely remove the glibc dependency. |
| #include "pub_core_basics.h" |
| #include "pub_core_debuglog.h" |
| #include "pub_core_libcbase.h" |
| #include "pub_core_machine.h" |
| #include "pub_core_libcprint.h" |
| #include "pub_core_libcfile.h" // VG_(close) et al |
| #include "pub_core_libcproc.h" // VG_(geteuid), VG_(getegid) |
| #include "pub_core_libcassert.h" // VG_(exit), vg_assert |
| #include "pub_core_syscall.h" // VG_(strerror) |
| #include "pub_core_mallocfree.h" // VG_(malloc), VG_(free) |
| #include "pub_core_aspacemgr.h" // various mapping fns |
| #include "vki_unistd.h" // mmap-related constants |
| |
| #include "pub_core_ume.h" |
| |
| |
| #if VG_WORDSIZE == 8 |
| #define ESZ(x) Elf64_##x |
| #elif VG_WORDSIZE == 4 |
| #define ESZ(x) Elf32_##x |
| #else |
| #error VG_WORDSIZE needs to ==4 or ==8 |
| #endif |
| |
| struct elfinfo |
| { |
| ESZ(Ehdr) e; |
| ESZ(Phdr) *p; |
| int fd; |
| }; |
| |
| static void check_mmap(SysRes res, Addr base, SizeT len) |
| { |
| if (res.isError) { |
| VG_(printf)("valgrind: mmap(0x%llx, %lld) failed in UME.\n", |
| (ULong)base, (Long)len); |
| VG_(exit)(1); |
| } |
| } |
| |
| //zz // 'extra' allows the caller to pass in extra args to 'fn', like free |
| //zz // variables to a closure. |
| //zz void VG_(foreach_map)(int (*fn)(char *start, char *end, |
| //zz const char *perm, off_t offset, |
| //zz int maj, int min, int ino, void* extra), |
| //zz void* extra) |
| //zz { |
| //zz static char buf[10240]; |
| //zz char *bufptr = buf; |
| //zz int ret, fd; |
| //zz |
| //zz fd = open("/proc/self/maps", O_RDONLY); |
| //zz |
| //zz if (fd == -1) { |
| //zz perror("open /proc/self/maps"); |
| //zz return; |
| //zz } |
| //zz |
| //zz ret = read(fd, buf, sizeof(buf)); |
| //zz |
| //zz if (ret == -1) { |
| //zz perror("read /proc/self/maps"); |
| //zz close(fd); |
| //zz return; |
| //zz } |
| //zz close(fd); |
| //zz |
| //zz if (ret == sizeof(buf)) { |
| //zz VG_(printf)("coregrind/m_ume.c: buf too small\n"); |
| //zz return; |
| //zz } |
| //zz |
| //zz while(bufptr && bufptr < buf+ret) { |
| //zz char perm[5]; |
| //zz ULong offset; |
| //zz int maj, min; |
| //zz int ino; |
| //zz void *segstart, *segend; |
| //zz |
| //zz sscanf(bufptr, "%p-%p %s %llx %x:%x %d", |
| //zz &segstart, &segend, perm, &offset, &maj, &min, &ino); |
| //zz bufptr = strchr(bufptr, '\n'); |
| //zz if (bufptr != NULL) |
| //zz bufptr++; /* skip \n */ |
| //zz |
| //zz if (!(*fn)(segstart, segend, perm, offset, maj, min, ino, extra)) |
| //zz break; |
| //zz } |
| //zz } |
| //zz |
| //zz /*------------------------------------------------------------*/ |
| //zz /*--- Stack switching ---*/ |
| //zz /*------------------------------------------------------------*/ |
| //zz |
| //zz // __attribute__((noreturn)) |
| //zz // void VG_(jump_and_switch_stacks) ( Addr stack, Addr dst ); |
| //zz #if defined(VGA_x86) |
| //zz // 4(%esp) == stack |
| //zz // 8(%esp) == dst |
| //zz asm( |
| //zz ".global vgPlain_jump_and_switch_stacks\n" |
| //zz "vgPlain_jump_and_switch_stacks:\n" |
| //zz " movl %esp, %esi\n" // remember old stack pointer |
| //zz " movl 4(%esi), %esp\n" // set stack |
| //zz " pushl 8(%esi)\n" // dst to stack |
| //zz " movl $0, %eax\n" // zero all GP regs |
| //zz " movl $0, %ebx\n" |
| //zz " movl $0, %ecx\n" |
| //zz " movl $0, %edx\n" |
| //zz " movl $0, %esi\n" |
| //zz " movl $0, %edi\n" |
| //zz " movl $0, %ebp\n" |
| //zz " ret\n" // jump to dst |
| //zz " ud2\n" // should never get here |
| //zz ); |
| //zz #elif defined(VGA_amd64) |
| //zz // %rdi == stack |
| //zz // %rsi == dst |
| //zz asm( |
| //zz ".global vgPlain_jump_and_switch_stacks\n" |
| //zz "vgPlain_jump_and_switch_stacks:\n" |
| //zz " movq %rdi, %rsp\n" // set stack |
| //zz " pushq %rsi\n" // dst to stack |
| //zz " movq $0, %rax\n" // zero all GP regs |
| //zz " movq $0, %rbx\n" |
| //zz " movq $0, %rcx\n" |
| //zz " movq $0, %rdx\n" |
| //zz " movq $0, %rsi\n" |
| //zz " movq $0, %rdi\n" |
| //zz " movq $0, %rbp\n" |
| //zz " movq $0, %r8\n" |
| //zz " movq $0, %r9\n" |
| //zz " movq $0, %r10\n" |
| //zz " movq $0, %r11\n" |
| //zz " movq $0, %r12\n" |
| //zz " movq $0, %r13\n" |
| //zz " movq $0, %r14\n" |
| //zz " movq $0, %r15\n" |
| //zz " ret\n" // jump to dst |
| //zz " ud2\n" // should never get here |
| //zz ); |
| //zz |
| //zz #elif defined(VGA_ppc32) |
| //zz /* Jump to 'dst', but first set the stack pointer to 'stack'. Also, |
| //zz clear all the integer registers before entering 'dst'. It's |
| //zz important that the stack pointer is set to exactly 'stack' and not |
| //zz (eg) stack - apparently_harmless_looking_small_offset. Basically |
| //zz because the code at 'dst' might be wanting to scan the area above |
| //zz 'stack' (viz, the auxv array), and putting spurious words on the |
| //zz stack confuses it. |
| //zz */ |
| //zz // %r3 == stack |
| //zz // %r4 == dst |
| //zz asm( |
| //zz ".global vgPlain_jump_and_switch_stacks\n" |
| //zz "vgPlain_jump_and_switch_stacks:\n" |
| //zz " mtctr %r4\n\t" // dst to %ctr |
| //zz " mr %r1,%r3\n\t" // stack to %sp |
| //zz " li 0,0\n\t" // zero all GP regs |
| //zz " li 3,0\n\t" |
| //zz " li 4,0\n\t" |
| //zz " li 5,0\n\t" |
| //zz " li 6,0\n\t" |
| //zz " li 7,0\n\t" |
| //zz " li 8,0\n\t" |
| //zz " li 9,0\n\t" |
| //zz " li 10,0\n\t" |
| //zz " li 11,0\n\t" |
| //zz " li 12,0\n\t" |
| //zz " li 13,0\n\t" // CAB: This right? r13 = small data area ptr |
| //zz " li 14,0\n\t" |
| //zz " li 15,0\n\t" |
| //zz " li 16,0\n\t" |
| //zz " li 17,0\n\t" |
| //zz " li 18,0\n\t" |
| //zz " li 19,0\n\t" |
| //zz " li 20,0\n\t" |
| //zz " li 21,0\n\t" |
| //zz " li 22,0\n\t" |
| //zz " li 23,0\n\t" |
| //zz " li 24,0\n\t" |
| //zz " li 25,0\n\t" |
| //zz " li 26,0\n\t" |
| //zz " li 27,0\n\t" |
| //zz " li 28,0\n\t" |
| //zz " li 29,0\n\t" |
| //zz " li 30,0\n\t" |
| //zz " li 31,0\n\t" |
| //zz " mtxer 0\n\t" |
| //zz " mtcr 0\n\t" |
| //zz " mtlr %r0\n\t" |
| //zz " bctr\n\t" // jump to dst |
| //zz " trap\n" // should never get here |
| //zz ); |
| //zz |
| //zz #else |
| //zz # error Unknown architecture |
| //zz #endif |
| |
| /*------------------------------------------------------------*/ |
| /*--- Finding auxv on the stack ---*/ |
| /*------------------------------------------------------------*/ |
| |
| struct ume_auxv *VG_(find_auxv)(UWord* sp) |
| { |
| sp++; // skip argc (Nb: is word-sized, not int-sized!) |
| |
| while (*sp != 0) // skip argv |
| sp++; |
| sp++; |
| |
| while (*sp != 0) // skip env |
| sp++; |
| sp++; |
| |
| #if defined(VGA_ppc32) |
| # if defined AT_IGNOREPPC |
| while (*sp == AT_IGNOREPPC) // skip AT_IGNOREPPC entries |
| sp += 2; |
| # endif |
| #endif |
| |
| return (struct ume_auxv *)sp; |
| } |
| |
| /*------------------------------------------------------------*/ |
| /*--- Loading ELF files ---*/ |
| /*------------------------------------------------------------*/ |
| |
| static |
| struct elfinfo *readelf(int fd, const char *filename) |
| { |
| SysRes sres; |
| struct elfinfo *e = VG_(malloc)(sizeof(*e)); |
| int phsz; |
| |
| vg_assert(e); |
| e->fd = fd; |
| |
| sres = VG_(pread)(fd, &e->e, sizeof(e->e), 0); |
| if (sres.isError || sres.val != sizeof(e->e)) { |
| VG_(printf)("valgrind: %s: can't read ELF header: %s\n", |
| filename, VG_(strerror)(sres.val)); |
| goto bad; |
| } |
| |
| if (VG_(memcmp)(&e->e.e_ident[0], ELFMAG, SELFMAG) != 0) { |
| VG_(printf)("valgrind: %s: bad ELF magic number\n", filename); |
| goto bad; |
| } |
| if (e->e.e_ident[EI_CLASS] != VG_ELF_CLASS) { |
| VG_(printf)("valgrind: wrong ELF executable class " |
| "(eg. 32-bit instead of 64-bit)\n"); |
| goto bad; |
| } |
| if (e->e.e_ident[EI_DATA] != VG_ELF_DATA2XXX) { |
| VG_(printf)("valgrind: executable has wrong endian-ness\n"); |
| goto bad; |
| } |
| if (!(e->e.e_type == ET_EXEC || e->e.e_type == ET_DYN)) { |
| VG_(printf)("valgrind: this is not an executable\n"); |
| goto bad; |
| } |
| |
| if (e->e.e_machine != VG_ELF_MACHINE) { |
| VG_(printf)("valgrind: executable is not for " |
| "this architecture\n"); |
| goto bad; |
| } |
| |
| if (e->e.e_phentsize != sizeof(ESZ(Phdr))) { |
| VG_(printf)("valgrind: sizeof ELF Phdr wrong\n"); |
| goto bad; |
| } |
| |
| phsz = sizeof(ESZ(Phdr)) * e->e.e_phnum; |
| e->p = VG_(malloc)(phsz); |
| vg_assert(e->p); |
| |
| sres = VG_(pread)(fd, e->p, phsz, e->e.e_phoff); |
| if (sres.isError || sres.val != phsz) { |
| VG_(printf)("valgrind: can't read phdr: %s\n", |
| VG_(strerror)(sres.val)); |
| VG_(free)(e->p); |
| goto bad; |
| } |
| |
| return e; |
| |
| bad: |
| VG_(free)(e); |
| return NULL; |
| } |
| |
| /* Map an ELF file. Returns the brk address. */ |
| static |
| ESZ(Addr) mapelf(struct elfinfo *e, ESZ(Addr) base) |
| { |
| Int i; |
| SysRes res; |
| ESZ(Addr) elfbrk = 0; |
| |
| for(i = 0; i < e->e.e_phnum; i++) { |
| ESZ(Phdr) *ph = &e->p[i]; |
| ESZ(Addr) addr, brkaddr; |
| ESZ(Word) memsz; |
| |
| if (ph->p_type != PT_LOAD) |
| continue; |
| |
| addr = ph->p_vaddr+base; |
| memsz = ph->p_memsz; |
| brkaddr = addr+memsz; |
| |
| if (brkaddr > elfbrk) |
| elfbrk = brkaddr; |
| } |
| |
| for(i = 0; i < e->e.e_phnum; i++) { |
| ESZ(Phdr) *ph = &e->p[i]; |
| ESZ(Addr) addr, bss, brkaddr; |
| ESZ(Off) off; |
| ESZ(Word) filesz; |
| ESZ(Word) memsz; |
| unsigned prot = 0; |
| |
| if (ph->p_type != PT_LOAD) |
| continue; |
| |
| if (ph->p_flags & PF_X) prot |= VKI_PROT_EXEC; |
| if (ph->p_flags & PF_W) prot |= VKI_PROT_WRITE; |
| if (ph->p_flags & PF_R) prot |= VKI_PROT_READ; |
| |
| addr = ph->p_vaddr+base; |
| off = ph->p_offset; |
| filesz = ph->p_filesz; |
| bss = addr+filesz; |
| memsz = ph->p_memsz; |
| brkaddr = addr+memsz; |
| |
| // Tom says: In the following, do what the Linux kernel does and only |
| // map the pages that are required instead of rounding everything to |
| // the specified alignment (ph->p_align). (AMD64 doesn't work if you |
| // use ph->p_align -- part of stage2's memory gets trashed somehow.) |
| // |
| // The condition handles the case of a zero-length segment. |
| if (VG_PGROUNDUP(bss)-VG_PGROUNDDN(addr) > 0) { |
| if (0) VG_(debugLog)(0,"ume","mmap_file_fixed_client #1\n"); |
| res = VG_(am_mmap_file_fixed_client)( |
| VG_PGROUNDDN(addr), |
| VG_PGROUNDUP(bss)-VG_PGROUNDDN(addr), |
| prot, /*VKI_MAP_FIXED|VKI_MAP_PRIVATE, */ |
| e->fd, VG_PGROUNDDN(off) |
| ); |
| if (0) VG_(am_show_nsegments)(0,"after #1"); |
| check_mmap(res, VG_PGROUNDDN(addr), |
| VG_PGROUNDUP(bss)-VG_PGROUNDDN(addr)); |
| } |
| |
| // if memsz > filesz, fill the remainder with zeroed pages |
| if (memsz > filesz) { |
| UInt bytes; |
| |
| bytes = VG_PGROUNDUP(brkaddr)-VG_PGROUNDUP(bss); |
| if (bytes > 0) { |
| if (0) VG_(debugLog)(0,"ume","mmap_anon_fixed_client #2\n"); |
| res = VG_(am_mmap_anon_fixed_client)( |
| VG_PGROUNDUP(bss), bytes, |
| prot |
| ); |
| if (0) VG_(am_show_nsegments)(0,"after #2"); |
| check_mmap(res, VG_PGROUNDUP(bss), bytes); |
| } |
| |
| bytes = bss & (VKI_PAGE_SIZE - 1); |
| |
| // The 'prot' condition allows for a read-only bss |
| if ((prot & VKI_PROT_WRITE) && (bytes > 0)) { |
| bytes = VKI_PAGE_SIZE - bytes; |
| VG_(memset)((char *)bss, 0, bytes); |
| } |
| } |
| } |
| |
| return elfbrk; |
| } |
| |
| // Forward declaration. |
| /* returns: 0 = success, non-0 is failure */ |
| static int do_exec_inner(const char *exe, struct exeinfo *info); |
| |
| static int match_ELF(const char *hdr, int len) |
| { |
| ESZ(Ehdr) *e = (ESZ(Ehdr) *)hdr; |
| return (len > sizeof(*e)) && VG_(memcmp)(&e->e_ident[0], ELFMAG, SELFMAG) == 0; |
| } |
| |
| |
| /* load_ELF pulls an ELF executable into the address space, prepares |
| it for execution, and writes info about it into INFO. In |
| particular it fills in .init_eip, which is the starting point. |
| |
| Returns zero on success, non-zero (a VKI_E.. value) on failure. |
| |
| The sequence of activities is roughly as follows: |
| |
| - use readelf() to extract program header info from the exe file. |
| |
| - scan the program header, collecting info (not sure what all those |
| info-> fields are, or whether they are used, but still) and in |
| particular looking out fo the PT_INTERP header, which describes |
| the interpreter. If such a field is found, the space needed to |
| hold the interpreter is computed into interp_size. |
| |
| - map the executable in, by calling mapelf(). This maps in all |
| loadable sections, and I _think_ also creates any .bss areas |
| required. mapelf() returns the address just beyond the end of |
| the furthest-along mapping it creates. The executable is mapped |
| starting at EBASE, which is usually read from it (eg, 0x8048000 |
| etc) except if it's a PIE, in which case I'm not sure what |
| happens. |
| |
| The returned address is recorded in info->brkbase as the start |
| point of the brk (data) segment, as it is traditional to place |
| the data segment just after the executable. Neither load_ELF nor |
| mapelf creates the brk segment, though: that is for the caller of |
| load_ELF to attend to. |
| |
| - If the initial phdr scan didn't find any mention of an |
| interpreter (interp == NULL), this must be a statically linked |
| executable, and we're pretty much done. |
| |
| - Otherwise, we need to use mapelf() a second time to load the |
| interpreter. The interpreter can go anywhere, but mapelf() wants |
| to be told a specific address to put it at. So an advisory query |
| is passed to aspacem, asking where it would put an anonymous |
| client mapping of size INTERP_SIZE. That address is then used |
| as the mapping address for the interpreter. |
| |
| - The entry point in INFO is set to the interpreter's entry point, |
| and we're done. */ |
| static int load_ELF(char *hdr, int len, int fd, const char *name, |
| /*MOD*/struct exeinfo *info) |
| { |
| SysRes sres; |
| struct elfinfo *e; |
| struct elfinfo *interp = NULL; |
| ESZ(Addr) minaddr = ~0; /* lowest mapped address */ |
| ESZ(Addr) maxaddr = 0; /* highest mapped address */ |
| ESZ(Addr) interp_addr = 0; /* interpreter (ld.so) address */ |
| ESZ(Word) interp_size = 0; /* interpreter size */ |
| ESZ(Word) interp_align = VKI_PAGE_SIZE; |
| int i; |
| void *entry; |
| ESZ(Addr) ebase = 0; |
| |
| #ifdef HAVE_PIE |
| ebase = info->exe_base; |
| #endif |
| |
| e = readelf(fd, name); |
| |
| if (e == NULL) |
| return VKI_ENOEXEC; |
| |
| /* The kernel maps position-independent executables at TASK_SIZE*2/3; |
| duplicate this behavior as close as we can. */ |
| if (e->e.e_type == ET_DYN && ebase == 0) { |
| ebase = VG_PGROUNDDN(info->exe_base + (info->exe_end - info->exe_base) * 2 / 3); |
| } |
| |
| info->phnum = e->e.e_phnum; |
| info->entry = e->e.e_entry + ebase; |
| info->phdr = 0; |
| |
| for(i = 0; i < e->e.e_phnum; i++) { |
| ESZ(Phdr) *ph = &e->p[i]; |
| |
| switch(ph->p_type) { |
| case PT_PHDR: |
| info->phdr = ph->p_vaddr + ebase; |
| break; |
| |
| case PT_LOAD: |
| if (ph->p_vaddr < minaddr) |
| minaddr = ph->p_vaddr; |
| if (ph->p_vaddr+ph->p_memsz > maxaddr) |
| maxaddr = ph->p_vaddr+ph->p_memsz; |
| break; |
| |
| case PT_INTERP: { |
| char *buf = VG_(malloc)(ph->p_filesz+1); |
| int j; |
| int intfd; |
| int baseaddr_set; |
| |
| vg_assert(buf); |
| VG_(pread)(fd, buf, ph->p_filesz, ph->p_offset); |
| buf[ph->p_filesz] = '\0'; |
| |
| sres = VG_(open)(buf, VKI_O_RDONLY, 0); |
| if (sres.isError) { |
| VG_(printf)("valgrind: m_ume.c: can't open interpreter\n"); |
| VG_(exit)(1); |
| } |
| intfd = sres.val; |
| |
| interp = readelf(intfd, buf); |
| if (interp == NULL) { |
| VG_(printf)("valgrind: m_ume.c: can't read interpreter\n"); |
| return 1; |
| } |
| VG_(free)(buf); |
| |
| baseaddr_set = 0; |
| for(j = 0; j < interp->e.e_phnum; j++) { |
| ESZ(Phdr) *iph = &interp->p[j]; |
| ESZ(Addr) end; |
| |
| if (iph->p_type != PT_LOAD) |
| continue; |
| |
| if (!baseaddr_set) { |
| interp_addr = iph->p_vaddr; |
| interp_align = iph->p_align; |
| baseaddr_set = 1; |
| } |
| |
| /* assumes that all segments in the interp are close */ |
| end = (iph->p_vaddr - interp_addr) + iph->p_memsz; |
| |
| if (end > interp_size) |
| interp_size = end; |
| } |
| break; |
| |
| default: |
| // do nothing |
| break; |
| } |
| } |
| } |
| |
| if (info->phdr == 0) |
| info->phdr = minaddr + ebase + e->e.e_phoff; |
| |
| if (info->exe_base != info->exe_end) { |
| if (minaddr >= maxaddr || |
| (minaddr + ebase < info->exe_base || |
| maxaddr + ebase > info->exe_end)) { |
| VG_(printf)("Executable range %p-%p is outside the\n" |
| "acceptable range %p-%p\n", |
| (void *)minaddr + ebase, (void *)maxaddr + ebase, |
| (void *)info->exe_base, (void *)info->exe_end); |
| return VKI_ENOMEM; |
| } |
| } |
| |
| info->brkbase = mapelf(e, ebase); /* map the executable */ |
| |
| if (info->brkbase == 0) |
| return VKI_ENOMEM; |
| |
| if (interp != NULL) { |
| /* reserve a chunk of address space for interpreter */ |
| Addr advised; |
| Bool ok; |
| |
| /* Don't actually reserve the space. Just get an advisory |
| indicating where it would be allocated, and pass that to |
| mapelf(), which in turn asks aspacem to do some fixed maps at |
| the specified address. This is a bit of hack, but it should |
| work because there should be no intervening transactions with |
| aspacem which could cause those fixed maps to fail. */ |
| advised = VG_(am_get_advisory_client_simple)( |
| (Addr)interp_addr, interp_size, &ok |
| ); |
| if (!ok) { |
| /* bomb out */ |
| SysRes res = VG_(mk_SysRes_Error)(VKI_EINVAL); |
| if (0) VG_(printf)("reserve for interp: failed\n"); |
| check_mmap(res, (Addr)interp_addr, interp_size); |
| /*NOTREACHED*/ |
| } |
| |
| (void)mapelf(interp, (ESZ(Addr))advised - interp_addr); |
| |
| VG_(close)(interp->fd); |
| |
| entry = (void *)(advised - interp_addr + interp->e.e_entry); |
| info->interp_base = (ESZ(Addr))advised; |
| |
| VG_(free)(interp->p); |
| VG_(free)(interp); |
| } else |
| entry = (void *)(ebase + e->e.e_entry); |
| |
| info->exe_base = minaddr + ebase; |
| info->exe_end = maxaddr + ebase; |
| |
| info->init_eip = (Addr)entry; |
| |
| VG_(free)(e->p); |
| VG_(free)(e); |
| |
| return 0; |
| } |
| |
| |
| static int match_script(const char *hdr, Int len) |
| { |
| return (len > 2) && VG_(memcmp)(hdr, "#!", 2) == 0; |
| } |
| |
| /* returns: 0 = success, non-0 is failure */ |
| static int load_script(char *hdr, int len, int fd, const char *name, |
| struct exeinfo *info) |
| { |
| char *interp; |
| char *const end = hdr+len; |
| char *cp; |
| char *arg = NULL; |
| int eol; |
| |
| interp = hdr + 2; |
| while(interp < end && (*interp == ' ' || *interp == '\t')) |
| interp++; |
| |
| if (*interp != '/') |
| return VKI_ENOEXEC; /* absolute path only for interpreter */ |
| |
| /* skip over interpreter name */ |
| for(cp = interp; cp < end && *cp != ' ' && *cp != '\t' && *cp != '\n'; cp++) |
| ; |
| |
| eol = (*cp == '\n'); |
| |
| *cp++ = '\0'; |
| |
| if (!eol && cp < end) { |
| /* skip space before arg */ |
| while (cp < end && (*cp == '\t' || *cp == ' ')) |
| cp++; |
| |
| /* arg is from here to eol */ |
| arg = cp; |
| while (cp < end && *cp != '\n') |
| cp++; |
| *cp = '\0'; |
| } |
| |
| info->interp_name = VG_(strdup)(interp); |
| vg_assert(NULL != info->interp_name); |
| if (arg != NULL && *arg != '\0') { |
| info->interp_args = VG_(strdup)(arg); |
| vg_assert(NULL != info->interp_args); |
| } |
| |
| if (info->argv && info->argv[0] != NULL) |
| info->argv[0] = (char *)name; |
| |
| if (0) |
| VG_(printf)("#! script: interp_name=\"%s\" interp_args=\"%s\"\n", |
| info->interp_name, info->interp_args); |
| |
| return do_exec_inner(interp, info); |
| } |
| |
| /* |
| Emulate the normal Unix permissions checking algorithm. |
| |
| If owner matches, then use the owner permissions, else |
| if group matches, then use the group permissions, else |
| use other permissions. |
| |
| Note that we can't deal with SUID/SGID, so we refuse to run them |
| (otherwise the executable may misbehave if it doesn't have the |
| permissions it thinks it does). |
| */ |
| /* returns: 0 = success, non-0 is failure */ |
| static int check_perms(int fd) |
| { |
| struct vki_stat st; |
| |
| if (VG_(fstat)(fd, &st) == -1) |
| return VKI_EACCES; |
| |
| if (st.st_mode & (VKI_S_ISUID | VKI_S_ISGID)) { |
| //VG_(printf)("Can't execute suid/sgid executable %s\n", exe); |
| return VKI_EACCES; |
| } |
| |
| if (VG_(geteuid)() == st.st_uid) { |
| if (!(st.st_mode & VKI_S_IXUSR)) |
| return VKI_EACCES; |
| } else { |
| int grpmatch = 0; |
| |
| if (VG_(getegid)() == st.st_gid) |
| grpmatch = 1; |
| else { |
| UInt groups[32]; |
| Int ngrp = VG_(getgroups)(32, groups); |
| Int i; |
| /* ngrp will be -1 if VG_(getgroups) failed. */ |
| for (i = 0; i < ngrp; i++) { |
| if (groups[i] == st.st_gid) { |
| grpmatch = 1; |
| break; |
| } |
| } |
| } |
| |
| if (grpmatch) { |
| if (!(st.st_mode & VKI_S_IXGRP)) |
| return VKI_EACCES; |
| } else if (!(st.st_mode & VKI_S_IXOTH)) |
| return VKI_EACCES; |
| } |
| |
| return 0; |
| } |
| |
| /* returns: 0 = success, non-0 is failure */ |
| static int do_exec_inner(const char *exe, struct exeinfo *info) |
| { |
| SysRes sres; |
| int fd; |
| int err; |
| char buf[VKI_PAGE_SIZE]; |
| int bufsz; |
| int i; |
| int ret; |
| static const struct { |
| int (*match)(const char *hdr, int len); |
| int (*load) ( char *hdr, int len, int fd2, const char *name, |
| struct exeinfo *); |
| } formats[] = { |
| { match_ELF, load_ELF }, |
| { match_script, load_script }, |
| }; |
| |
| sres = VG_(open)(exe, VKI_O_RDONLY, 0); |
| if (sres.isError) { |
| if (0) |
| VG_(printf)("Can't open executable %s: %s\n", |
| exe, VG_(strerror)(sres.val)); |
| return sres.val; |
| } |
| fd = sres.val; |
| |
| err = check_perms(fd); |
| if (err != 0) { |
| VG_(close)(fd); |
| return err; |
| } |
| |
| bufsz = VG_(fsize)(fd); |
| if (bufsz > sizeof(buf)) |
| bufsz = sizeof(buf); |
| |
| sres = VG_(pread)(fd, buf, bufsz, 0); |
| if (sres.isError || sres.val != bufsz) { |
| VG_(printf)("Can't read executable header: %s\n", |
| VG_(strerror)(sres.val)); |
| VG_(close)(fd); |
| return sres.val; |
| } |
| bufsz = sres.val; |
| |
| ret = VKI_ENOEXEC; |
| for(i = 0; i < sizeof(formats)/sizeof(*formats); i++) { |
| if ((formats[i].match)(buf, bufsz)) { |
| ret = (formats[i].load)(buf, bufsz, fd, exe, info); |
| break; |
| } |
| } |
| |
| VG_(close)(fd); |
| |
| return ret; |
| } |
| |
| // See ume.h for an indication of which entries of 'info' are inputs, which |
| // are outputs, and which are both. |
| /* returns: 0 = success, non-0 is failure */ |
| int VG_(do_exec)(const char *exe, struct exeinfo *info) |
| { |
| info->interp_name = NULL; |
| info->interp_args = NULL; |
| |
| return do_exec_inner(exe, info); |
| } |
| |
| /*--------------------------------------------------------------------*/ |
| /*--- end ---*/ |
| /*--------------------------------------------------------------------*/ |