diff options
Diffstat (limited to 'libsigsegv/src/stackvma-procfs.c')
| -rw-r--r-- | libsigsegv/src/stackvma-procfs.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/libsigsegv/src/stackvma-procfs.c b/libsigsegv/src/stackvma-procfs.c new file mode 100644 index 00000000..24c90a1a --- /dev/null +++ b/libsigsegv/src/stackvma-procfs.c @@ -0,0 +1,188 @@ +/* Determine the virtual memory area of a given address. + Copyright (C) 2002, 2006, 2008 Bruno Haible <bruno@clisp.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, 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ + +#include "stackvma.h" +#include <unistd.h> /* open, close */ +#include <fcntl.h> /* open */ +#include <sys/types.h> +#include <sys/mman.h> /* mmap, munmap */ +#include <sys/procfs.h> /* PIOC*, prmap_t */ + +#include "stackvma-simple.c" + +#if HAVE_MINCORE +# define sigsegv_get_vma mincore_get_vma +# define STATIC static +# include "stackvma-mincore.c" +# undef sigsegv_get_vma +#else +/* Cache for getpagesize(). */ +static unsigned long pagesize; +/* Initialize pagesize. */ +static void +init_pagesize (void) +{ + pagesize = getpagesize (); +} +#endif + +int +sigsegv_get_vma (unsigned long address, struct vma_struct *vma) +{ + char fnamebuf[6+10+1]; + char *fname; + int fd; + int nmaps; + size_t memneed; +#if HAVE_MMAP_ANON +# define zero_fd -1 +# define map_flags MAP_ANON +#elif HAVE_MMAP_ANONYMOUS +# define zero_fd -1 +# define map_flags MAP_ANONYMOUS +#else + int zero_fd; +# define map_flags 0 +#endif + void *auxmap; + unsigned long auxmap_start; + unsigned long auxmap_end; + prmap_t* maps; + prmap_t* mp; + unsigned long start, end; +#if STACK_DIRECTION < 0 + unsigned long prev; +#endif + + if (pagesize == 0) + init_pagesize (); + + /* Construct fname = sprintf (fnamebuf+i, "/proc/%u", getpid ()). */ + fname = fnamebuf + sizeof (fnamebuf) - 1; + *fname = '\0'; + { + unsigned int value = getpid (); + do + *--fname = (value % 10) + '0'; + while ((value = value / 10) > 0); + } + fname -= 6; + memcpy (fname, "/proc/", 6); + + fd = open (fname, O_RDONLY); + if (fd < 0) + goto failed; + + if (ioctl (fd, PIOCNMAP, &nmaps) < 0) + goto fail2; + + memneed = (nmaps + 10) * sizeof (prmap_t); + /* Allocate memneed bytes of memory. + We cannot use alloca here, because we are low on stack space. + We also cannot use malloc here, because a malloc() call may have been + interrupted. + So use mmap(), and ignore the resulting VMA. */ + memneed = ((memneed - 1) / pagesize + 1) * pagesize; +#if !(HAVE_MMAP_ANON || HAVE_MMAP_ANONYMOUS) + zero_fd = open ("/dev/zero", O_RDONLY, 0644); + if (zero_fd < 0) + goto fail2; +#endif + auxmap = (void *) mmap ((void *) 0, memneed, PROT_READ | PROT_WRITE, map_flags | MAP_PRIVATE, zero_fd, 0); +#if !(HAVE_MMAP_ANON || HAVE_MMAP_ANONYMOUS) + close (zero_fd); +#endif + if (auxmap == (void *) -1) + goto fail2; + auxmap_start = (unsigned long) auxmap; + auxmap_end = auxmap_start + memneed; + maps = (prmap_t *) auxmap; + + if (ioctl (fd, PIOCMAP, maps) < 0) + goto fail1; + +#if STACK_DIRECTION < 0 + prev = 0; +#endif + for (mp = maps;;) + { + start = (unsigned long) mp->pr_vaddr; + end = start + mp->pr_size; + if (start == 0 && end == 0) + break; + mp++; + if (start <= auxmap_start && auxmap_end - 1 <= end - 1) + { + /* Consider [start,end-1] \ [auxmap_start,auxmap_end-1] + = [start,auxmap_start-1] u [auxmap_end,end-1]. */ + if (start != auxmap_start) + { + if (address >= start && address <= auxmap_start - 1) + { + end = auxmap_start; + goto found; + } +#if STACK_DIRECTION < 0 + prev = auxmap_start; +#endif + } + if (end != auxmap_end) + { + if (address >= auxmap_end && address <= end - 1) + { + start = auxmap_end; + goto found; + } +#if STACK_DIRECTION < 0 + prev = end; +#endif + } + } + else + { + if (address >= start && address <= end - 1) + goto found; +#if STACK_DIRECTION < 0 + prev = end; +#endif + } + } + + fail1: + munmap (auxmap, memneed); + fail2: + close (fd); + failed: +#if HAVE_MINCORE + return mincore_get_vma (address, vma); +#else + return -1; +#endif + + found: + vma->start = start; + vma->end = end; +#if STACK_DIRECTION < 0 + vma->prev_end = prev; +#else + vma->next_start = (unsigned long) mp->pr_vaddr; +#endif + munmap (auxmap, memneed); + close (fd); + vma->is_near_this = simple_is_near_this; + return 0; +} |