diff options
| -rw-r--r-- | libc/sysdeps/linux/arm/mmap.c | 11 | ||||
| -rw-r--r-- | libc/sysdeps/linux/common/mmap64.c | 9 | ||||
| -rw-r--r-- | test/mmap/mmap2.c | 41 |
3 files changed, 57 insertions, 4 deletions
diff --git a/libc/sysdeps/linux/arm/mmap.c b/libc/sysdeps/linux/arm/mmap.c index 2eea38efc..63f76d7db 100644 --- a/libc/sysdeps/linux/arm/mmap.c +++ b/libc/sysdeps/linux/arm/mmap.c @@ -27,7 +27,6 @@ __ptr_t mmap(__ptr_t addr, size_t len, int prot, #elif defined (__NR_mmap2) #define __NR__mmap __NR_mmap2 - #ifndef MMAP2_PAGE_SHIFT # define MMAP2_PAGE_SHIFT 12 #endif @@ -39,9 +38,17 @@ __ptr_t mmap(__ptr_t addr, size_t len, int prot, { /* check if offset is page aligned */ if (offset & ((1 << MMAP2_PAGE_SHIFT) - 1)) + { + __set_errno(EINVAL); return MAP_FAILED; + } +#ifdef __USE_FILE_OFFSET64 + return (__ptr_t) _mmap (addr, len, prot, flags, + fd,((__u_quad_t) offset >> MMAP2_PAGE_SHIFT)); +#else return (__ptr_t) _mmap (addr, len, prot, flags, - fd,(off_t) (offset >> MMAP2_PAGE_SHIFT)); + fd,((__u_long) offset >> MMAP2_PAGE_SHIFT)); +#endif } #elif defined (__NR_mmap) # define __NR__mmap __NR_mmap diff --git a/libc/sysdeps/linux/common/mmap64.c b/libc/sysdeps/linux/common/mmap64.c index 2cf200dc9..85b0a6f17 100644 --- a/libc/sysdeps/linux/common/mmap64.c +++ b/libc/sysdeps/linux/common/mmap64.c @@ -58,8 +58,13 @@ __ptr_t mmap64(__ptr_t addr, size_t len, int prot, int flags, int fd, __off64_t __set_errno(EINVAL); return MAP_FAILED; } - - return __syscall_mmap2(addr, len, prot, flags, fd, (off_t) (offset >> MMAP2_PAGE_SHIFT)); +#ifdef __USE_FILE_OFFSET64 + return __syscall_mmap2(addr, len, prot, flags, + fd,((__u_quad_t)offset >> MMAP2_PAGE_SHIFT)); +#else + return __syscall_mmap2(addr, len, prot, flags, + fd,((__ulong_t)offset >> MMAP2_PAGE_SHIFT)); +#endif } # endif diff --git a/test/mmap/mmap2.c b/test/mmap/mmap2.c new file mode 100644 index 000000000..b9a8f9ac4 --- /dev/null +++ b/test/mmap/mmap2.c @@ -0,0 +1,41 @@ +/* When trying to map /dev/mem with offset 0xFFFFF000 on the ARM platform, mmap + * returns -EOVERFLOW. + * + * Since off_t is defined as a long int and the sign bit is set in the address, + * the shift operation shifts in ones instead of zeroes + * from the left. This results the offset sent to the kernel function becomes + * 0xFFFFFFFF instead of 0x000FFFFF with MMAP2_PAGE_SHIFT set to 12. + */ + +#include <unistd.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <errno.h> +#include <fcntl.h> +#include <sys/mman.h> + +#define FATAL do { fprintf(stderr, "Error at line %d, file %s (%d) [%s]\n", \ + __LINE__, __FILE__, errno, strerror(errno)); exit(1); } while(0) + +#define MAP_SIZE 4096UL +#define MAP_MASK (MAP_SIZE - 1) + +int main(int argc, char **argv) { + void* map_base = 0; + int fd; + off_t target = 0xfffff000; + if((fd = open("/dev/mem", O_RDWR | O_SYNC)) == -1) FATAL; + printf("/dev/mem opened.\n"); + fflush(stdout); + + /* Map one page */ + map_base = mmap(0, MAP_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, + fd, target & ~MAP_MASK); + if(map_base == (void *) -1) FATAL; + printf("Memory mapped at address %p.\n", map_base); + fflush(stdout); + if(munmap(map_base, MAP_SIZE) == -1) FATAL; + close(fd); + return 0; +} |