| |
| /*--------------------------------------------------------------------*/ |
| /*--- 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) 2000-2008 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. |
| */ |
| |
| |
| #include "pub_core_basics.h" |
| #include "pub_core_vki.h" |
| |
| #if defined(VGO_linux) |
| |
| #include "pub_core_aspacemgr.h" // various mapping fns |
| #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_mallocfree.h" // VG_(malloc), VG_(free) |
| #include "pub_core_syscall.h" // VG_(strerror) |
| #include "pub_core_options.h" // VG_(clo_xml) |
| #include "pub_core_ume.h" // self |
| |
| /* --- !!! --- EXTERNAL HEADERS start --- !!! --- */ |
| #define _GNU_SOURCE |
| #define _FILE_OFFSET_BITS 64 |
| /* This is for ELF types etc, and also the AT_ constants. */ |
| #include <elf.h> |
| /* --- !!! --- EXTERNAL HEADERS end --- !!! --- */ |
| |
| |
| #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 " |
| "with error %lu (%s).\n", |
| (ULong)base, (Long)len, |
| res.err, VG_(strerror)(res.err) ); |
| if (res.err == VKI_EINVAL) { |
| VG_(printf)("valgrind: this can be caused by executables with " |
| "very large text, data or bss segments.\n"); |
| } |
| VG_(exit)(1); |
| } |
| } |
| |
| /*------------------------------------------------------------*/ |
| /*--- 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) || defined(VGA_ppc64) |
| # 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)("ume.re.1", sizeof(*e)); |
| Int phsz; |
| |
| vg_assert(e); |
| e->fd = fd; |
| |
| sres = VG_(pread)(fd, &e->e, sizeof(e->e), 0); |
| if (sres.isError || sres.res != sizeof(e->e)) { |
| VG_(printf)("valgrind: %s: can't read ELF header: %s\n", |
| filename, VG_(strerror)(sres.err)); |
| 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)("ume.re.2", phsz); |
| vg_assert(e->p); |
| |
| sres = VG_(pread)(fd, e->p, phsz, e->e.e_phoff); |
| if (sres.isError || sres.res != phsz) { |
| VG_(printf)("valgrind: can't read phdr: %s\n", |
| VG_(strerror)(sres.err)); |
| 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; |
| } |
| |
| static Bool 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(Int fd, const HChar* name, /*MOD*/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; |
| |
| /* The difference between where the interpreter got mapped and |
| where it asked to be mapped. Needed for computing the ppc64 ELF |
| entry point and initial tocptr (R2) value. */ |
| ESZ(Word) interp_offset = 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); |
| /* We really don't want to load PIEs at zero or too close. It |
| works, but it's unrobust (NULL pointer reads and writes |
| become legit, which is really bad) and causes problems for |
| exp-ptrcheck, which assumes all numbers below 1MB are |
| nonpointers. So, hackily, move it above 1MB. */ |
| if (ebase < 0x100000) |
| ebase = 0x100000; |
| } |
| |
| 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: { |
| HChar *buf = VG_(malloc)("ume.LE.1", 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.res; |
| |
| 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", |
| (char *)minaddr + ebase, (char *)maxaddr + ebase, |
| (char *)info->exe_base, (char *)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 */ |
| MapRequest mreq; |
| 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. |
| |
| Placement policy is: |
| |
| if the interpreter asks to be loaded at zero |
| ignore that and put it wherever we like (mappings at zero |
| are bad news) |
| else |
| try and put it where it asks for, but if that doesn't work, |
| just put it anywhere. |
| */ |
| if (interp_addr == 0) { |
| mreq.rkind = MAny; |
| mreq.start = 0; |
| mreq.len = interp_size; |
| } else { |
| mreq.rkind = MHint; |
| mreq.start = interp_addr; |
| mreq.len = interp_size; |
| } |
| |
| advised = VG_(am_get_advisory)( &mreq, True/*client*/, &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; |
| interp_offset = advised - interp_addr; |
| |
| 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; |
| |
| #if defined(VGP_ppc64_linux) |
| /* On PPC64, a func ptr is represented by a TOC entry ptr. This |
| TOC entry contains three words; the first word is the function |
| address, the second word is the TOC ptr (r2), and the third word |
| is the static chain value. */ |
| info->init_ip = ((ULong*)entry)[0]; |
| info->init_toc = ((ULong*)entry)[1]; |
| info->init_ip += interp_offset; |
| info->init_toc += interp_offset; |
| #else |
| info->init_ip = (Addr)entry; |
| info->init_toc = 0; /* meaningless on this platform */ |
| #endif |
| VG_(free)(e->p); |
| VG_(free)(e); |
| |
| return 0; |
| } |
| |
| |
| static Bool match_script(char *hdr, Int len) |
| { |
| Char* end = hdr + len; |
| Char* interp = hdr + 2; |
| |
| // len < 4: need '#', '!', plus at least a '/' and one more char |
| if (len < 4) return False; |
| if (0 != VG_(memcmp)(hdr, "#!", 2)) return False; |
| |
| // Find interpreter name, make sure it's an absolute path (starts with |
| // '/') and has at least one more char. First, skip over any space |
| // between the #! and the start of the interpreter name |
| while (interp < end && VG_(isspace)(*interp)) interp++; |
| |
| // overrun? |
| if (interp >= end) return False; // can't find start of interp name |
| |
| // interp should now point at the / |
| if (*interp != '/') return False; // absolute path only for interpreter |
| |
| // check for something plausible after the / |
| interp++; |
| if (interp >= end) return False; |
| if (VG_(isspace)(*interp)) return False; |
| |
| // Here we should get the full interpreter name and check it with |
| // check_executable(). See the "EXEC FAILED" failure when running shell |
| // for an example. |
| |
| return True; // looks like a #! script |
| } |
| |
| // Forward declaration. |
| static Int do_exec_inner(const HChar* exe, ExeInfo* info); |
| |
| /* returns: 0 = success, non-0 is failure */ |
| static Int load_script(Int fd, const HChar* name, ExeInfo* info) |
| { |
| Char hdr[4096]; |
| Int len = 4096; |
| Int eol; |
| Char* interp; |
| Char* end; |
| Char* cp; |
| Char* arg = NULL; |
| SysRes res; |
| |
| // Read the first part of the file. |
| res = VG_(pread)(fd, hdr, len, 0); |
| if (res.isError) { |
| VG_(close)(fd); |
| return VKI_EACCES; |
| } else { |
| len = res.res; |
| } |
| |
| vg_assert('#' == hdr[0] && '!' == hdr[1]); |
| |
| end = hdr + len; |
| interp = hdr + 2; |
| while (interp < end && VG_(isspace)(*interp)) |
| interp++; |
| |
| vg_assert(*interp == '/'); /* absolute path only for interpreter */ |
| |
| /* skip over interpreter name */ |
| for (cp = interp; cp < end && !VG_(isspace)(*cp); cp++) |
| ; |
| |
| eol = (*cp == '\n'); |
| |
| *cp++ = '\0'; |
| |
| if (!eol && cp < end) { |
| /* skip space before arg */ |
| while (cp < end && VG_(isspace)(*cp) && *cp != '\n') |
| cp++; |
| |
| /* arg is from here to eol */ |
| arg = cp; |
| while (cp < end && *cp != '\n') |
| cp++; |
| *cp = '\0'; |
| } |
| |
| info->interp_name = VG_(strdup)("ume.ls.1", interp); |
| vg_assert(NULL != info->interp_name); |
| if (arg != NULL && *arg != '\0') { |
| info->interp_args = VG_(strdup)("ume.ls.2", 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); |
| } |
| |
| |
| typedef enum { |
| VG_EXE_FORMAT_ELF = 1, |
| VG_EXE_FORMAT_SCRIPT = 2, |
| } ExeFormat; |
| |
| // Check the file looks executable. |
| SysRes |
| VG_(pre_exec_check)(const HChar* exe_name, Int* out_fd, Bool allow_setuid) |
| { |
| Int fd, ret; |
| SysRes res; |
| Char buf[4096]; |
| SizeT bufsz = 4096, fsz; |
| Bool is_setuid = False; |
| |
| // Check it's readable |
| res = VG_(open)(exe_name, VKI_O_RDONLY, 0); |
| if (res.isError) { |
| return res; |
| } |
| fd = res.res; |
| |
| // Check we have execute permissions |
| ret = VG_(check_executable)(&is_setuid, (HChar*)exe_name, allow_setuid); |
| if (0 != ret) { |
| VG_(close)(fd); |
| if (is_setuid && !VG_(clo_xml)) { |
| VG_(message)(Vg_UserMsg, ""); |
| VG_(message)(Vg_UserMsg, |
| "Warning: Can't execute setuid/setgid executable: %s", |
| exe_name); |
| VG_(message)(Vg_UserMsg, "Possible workaround: remove " |
| "--trace-children=yes, if in effect"); |
| VG_(message)(Vg_UserMsg, ""); |
| } |
| return VG_(mk_SysRes_Error)(ret); |
| } |
| |
| fsz = (SizeT)VG_(fsize)(fd); |
| if (fsz < bufsz) |
| bufsz = fsz; |
| |
| res = VG_(pread)(fd, buf, bufsz, 0); |
| if (res.isError || res.res != bufsz) { |
| VG_(close)(fd); |
| return VG_(mk_SysRes_Error)(VKI_EACCES); |
| } |
| bufsz = res.res; |
| |
| if (match_ELF(buf, bufsz)) { |
| res = VG_(mk_SysRes_Success)(VG_EXE_FORMAT_ELF); |
| } else if (match_script(buf, bufsz)) { |
| res = VG_(mk_SysRes_Success)(VG_EXE_FORMAT_SCRIPT); |
| } else { |
| res = VG_(mk_SysRes_Error)(VKI_ENOEXEC); |
| } |
| |
| // Write the 'out_fd' param if necessary, or close the file. |
| if (!res.isError && out_fd) { |
| *out_fd = fd; |
| } else { |
| VG_(close)(fd); |
| } |
| |
| return res; |
| } |
| |
| // returns: 0 = success, non-0 is failure |
| // |
| // We can execute only ELF binaries or scripts that begin with "#!". (Not, |
| // for example, scripts that don't begin with "#!"; see the VG_(do_exec)() |
| // invocation from m_main.c for how that's handled.) |
| static Int do_exec_inner(const HChar *exe, ExeInfo* info) |
| { |
| SysRes res; |
| Int fd; |
| Int ret; |
| |
| res = VG_(pre_exec_check)(exe, &fd, False/*allow_setuid*/); |
| if (res.isError) |
| return res.err; |
| |
| switch (res.res) { |
| case VG_EXE_FORMAT_ELF: ret = load_ELF (fd, exe, info); break; |
| case VG_EXE_FORMAT_SCRIPT: ret = load_script(fd, exe, info); break; |
| default: |
| vg_assert2(0, "unrecognised VG_EXE_FORMAT value\n"); |
| } |
| |
| VG_(close)(fd); |
| |
| return ret; |
| } |
| |
| |
| static Bool is_hash_bang_file(Char* f) |
| { |
| SysRes res = VG_(open)(f, VKI_O_RDONLY, 0); |
| if (!res.isError) { |
| Char buf[3] = {0,0,0}; |
| Int fd = res.res; |
| Int n = VG_(read)(fd, buf, 2); |
| if (n == 2 && VG_STREQ("#!", buf)) |
| return True; |
| } |
| return False; |
| } |
| |
| // Look at the first 80 chars, and if any are greater than 127, it's binary. |
| // This is crude, but should be good enough. Note that it fails on a |
| // zero-length file, as we want. |
| static Bool is_binary_file(Char* f) |
| { |
| SysRes res = VG_(open)(f, VKI_O_RDONLY, 0); |
| if (!res.isError) { |
| UChar buf[80]; |
| Int fd = res.res; |
| Int n = VG_(read)(fd, buf, 80); |
| Int i; |
| for (i = 0; i < n; i++) { |
| if (buf[i] > 127) |
| return True; // binary char found |
| } |
| return False; |
| } else { |
| // Something went wrong. This will only happen if we earlier |
| // succeeded in opening the file but fail here (eg. the file was |
| // deleted between then and now). |
| VG_(printf)("valgrind: %s: unknown error\n", f); |
| VG_(exit)(126); // 126 == NOEXEC |
| } |
| } |
| |
| // If the do_exec fails we try to emulate what the shell does (I used |
| // bash as a guide). It's worth noting that the shell can execute some |
| // things that VG_(do_exec)() (which subsitutes for the kernel's exec()) |
| // will refuse to (eg. scripts lacking a "#!" prefix). |
| static Int do_exec_shell_followup(Int ret, HChar* exe_name, |
| ExeInfo* info) |
| { |
| Char* default_interp_name = "/bin/sh"; |
| SysRes res; |
| struct vg_stat st; |
| |
| if (VKI_ENOEXEC == ret) { |
| // It was an executable file, but in an unacceptable format. Probably |
| // is a shell script lacking the "#!" prefix; try to execute it so. |
| |
| // Is it a binary file? |
| if (is_binary_file(exe_name)) { |
| VG_(printf)("valgrind: %s: cannot execute binary file\n", exe_name); |
| VG_(exit)(126); // 126 == NOEXEC |
| } |
| |
| // Looks like a script. Run it with /bin/sh. This includes |
| // zero-length files. |
| |
| info->interp_name = VG_(strdup)("ume.desf.1", default_interp_name); |
| info->interp_args = NULL; |
| if (info->argv && info->argv[0] != NULL) |
| info->argv[0] = (char *)exe_name; |
| |
| ret = do_exec_inner(info->interp_name, info); |
| |
| if (0 != ret) { |
| // Something went wrong with executing the default interpreter |
| VG_(printf)("valgrind: %s: bad interpreter (%s): %s\n", |
| exe_name, info->interp_name, VG_(strerror)(ret)); |
| VG_(exit)(126); // 126 == NOEXEC |
| } |
| |
| } else if (0 != ret) { |
| // Something else went wrong. Try to make the error more specific, |
| // and then print a message and abort. |
| |
| // Was it a directory? |
| res = VG_(stat)(exe_name, &st); |
| if (!res.isError && VKI_S_ISDIR(st.st_mode)) { |
| VG_(printf)("valgrind: %s: is a directory\n", exe_name); |
| |
| // Was it not executable? |
| } else if (0 != VG_(check_executable)(NULL, exe_name, |
| False/*allow_setuid*/)) { |
| VG_(printf)("valgrind: %s: %s\n", exe_name, VG_(strerror)(ret)); |
| |
| // Did it start with "#!"? If so, it must have been a bad interpreter. |
| } else if (is_hash_bang_file(exe_name)) { |
| VG_(printf)("valgrind: %s: bad interpreter: %s\n", |
| exe_name, VG_(strerror)(ret)); |
| |
| // Otherwise it was something else. |
| } else { |
| VG_(printf)("valgrind: %s: %s\n", exe_name, VG_(strerror)(ret)); |
| } |
| // 126 means NOEXEC; I think this is Posix, and that in some cases we |
| // should be returning 127, meaning NOTFOUND. Oh well. |
| VG_(exit)(126); |
| } |
| return ret; |
| } |
| |
| |
| // This emulates the kernel's exec(). If it fails, it then emulates the |
| // shell's handling of the situation. |
| // 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 HChar* exe_name, ExeInfo* info) |
| { |
| Int ret; |
| |
| info->interp_name = NULL; |
| info->interp_args = NULL; |
| |
| ret = do_exec_inner(exe_name, info); |
| |
| if (0 != ret) { |
| Char* exe_name_casted = (Char*)exe_name; |
| ret = do_exec_shell_followup(ret, exe_name_casted, info); |
| } |
| return ret; |
| } |
| |
| #endif /* defined(VGO_linux) */ |
| |
| /*--------------------------------------------------------------------*/ |
| /*--- end ---*/ |
| /*--------------------------------------------------------------------*/ |