static int mmap_frag(abi_ulong real_start, abi_ulong start, abi_ulong end, int prot, int flags, int fd, abi_ulong offset) { abi_ulong real_end, addr; void *host_start; int prot1, prot_new; real_end = real_start + qemu_host_page_size; host_start = g2h(real_start); /* get the protection of the target pages outside the mapping */ prot1 = 0; for(addr = real_start; addr < real_end; addr++) { if (addr < start || addr >= end) prot1 |= page_get_flags(addr); } if (prot1 == 0) { /* no page was there, so we allocate one */ void *p = mmap(host_start, qemu_host_page_size, prot, flags | MAP_ANONYMOUS, -1, 0); if (p == MAP_FAILED) return -1; prot1 = prot; } prot1 &= PAGE_BITS; prot_new = prot | prot1; if (!(flags & MAP_ANONYMOUS)) { /* msync() won't work here, so we return an error if write is possible while it is a shared mapping */ if ((flags & MAP_TYPE) == MAP_SHARED && (prot & PROT_WRITE)) return -EINVAL; /* adjust protection to be able to read */ if (!(prot1 & PROT_WRITE)) mprotect(host_start, qemu_host_page_size, prot1 | PROT_WRITE); /* read the corresponding file data */ if (pread(fd, g2h(start), end - start, offset) == -1) return -1; /* put final protection */ if (prot_new != (prot1 | PROT_WRITE)) mprotect(host_start, qemu_host_page_size, prot_new); } else { /* just update the protection */ if (prot_new != prot1) { mprotect(host_start, qemu_host_page_size, prot_new); } } return 0; }