From 2aa362c49c314a98fb9aebbd7760a461667bac05 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Thu, 4 Oct 2012 17:15:36 -0700 Subject: [PATCH] coredump: extend core dump note section to contain file names of mapped files This note has the following format: long count -- how many files are mapped long page_size -- units for file_ofs array of [COUNT] elements of long start long end long file_ofs followed by COUNT filenames in ASCII: "FILE1" NUL "FILE2" NUL... Signed-off-by: Denys Vlasenko Cc: Oleg Nesterov Cc: Amerigo Wang Cc: "Jonathan M. Foote" Cc: Roland McGrath Cc: Pedro Alves Cc: Fengguang Wu Cc: Stephen Rothwell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/binfmt_elf.c | 110 +++++++++++++++++++++++++++++++++++++++-- fs/compat_binfmt_elf.c | 1 + include/linux/elf.h | 1 + 3 files changed, 108 insertions(+), 4 deletions(-) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 865f9be6a2d..28a64e76952 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -27,6 +27,7 @@ #include #include #include +#include #include #include #include @@ -37,6 +38,9 @@ #include #include +#ifndef user_long_t +#define user_long_t long +#endif #ifndef user_siginfo_t #define user_siginfo_t siginfo_t #endif @@ -1386,6 +1390,93 @@ static void fill_siginfo_note(struct memelfnote *note, user_siginfo_t *csigdata, fill_note(note, "CORE", NT_SIGINFO, sizeof(*csigdata), csigdata); } +#define MAX_FILE_NOTE_SIZE (4*1024*1024) +/* + * Format of NT_FILE note: + * + * long count -- how many files are mapped + * long page_size -- units for file_ofs + * array of [COUNT] elements of + * long start + * long end + * long file_ofs + * followed by COUNT filenames in ASCII: "FILE1" NUL "FILE2" NUL... + */ +static void fill_files_note(struct memelfnote *note) +{ + struct vm_area_struct *vma; + unsigned count, size, names_ofs, remaining, n; + user_long_t *data; + user_long_t *start_end_ofs; + char *name_base, *name_curpos; + + /* *Estimated* file count and total data size needed */ + count = current->mm->map_count; + size = count * 64; + + names_ofs = (2 + 3 * count) * sizeof(data[0]); + alloc: + if (size >= MAX_FILE_NOTE_SIZE) /* paranoia check */ + goto err; + size = round_up(size, PAGE_SIZE); + data = vmalloc(size); + if (!data) + goto err; + + start_end_ofs = data + 2; + name_base = name_curpos = ((char *)data) + names_ofs; + remaining = size - names_ofs; + count = 0; + for (vma = current->mm->mmap; vma != NULL; vma = vma->vm_next) { + struct file *file; + const char *filename; + + file = vma->vm_file; + if (!file) + continue; + filename = d_path(&file->f_path, name_curpos, remaining); + if (IS_ERR(filename)) { + if (PTR_ERR(filename) == -ENAMETOOLONG) { + vfree(data); + size = size * 5 / 4; + goto alloc; + } + continue; + } + + /* d_path() fills at the end, move name down */ + /* n = strlen(filename) + 1: */ + n = (name_curpos + remaining) - filename; + remaining = filename - name_curpos; + memmove(name_curpos, filename, n); + name_curpos += n; + + *start_end_ofs++ = vma->vm_start; + *start_end_ofs++ = vma->vm_end; + *start_end_ofs++ = vma->vm_pgoff; + count++; + } + + /* Now we know exact count of files, can store it */ + data[0] = count; + data[1] = PAGE_SIZE; + /* + * Count usually is less than current->mm->map_count, + * we need to move filenames down. + */ + n = current->mm->map_count - count; + if (n != 0) { + unsigned shift_bytes = n * 3 * sizeof(data[0]); + memmove(name_base - shift_bytes, name_base, + name_curpos - name_base); + name_curpos -= shift_bytes; + } + + size = name_curpos - (char *)data; + fill_note(note, "CORE", NT_FILE, size, data); + err: ; +} + #ifdef CORE_DUMP_USE_REGSET #include @@ -1401,6 +1492,7 @@ struct elf_note_info { struct memelfnote psinfo; struct memelfnote signote; struct memelfnote auxv; + struct memelfnote files; user_siginfo_t csigdata; size_t size; int thread_notes; @@ -1581,6 +1673,9 @@ static int fill_note_info(struct elfhdr *elf, int phdrs, fill_auxv_note(&info->auxv, current->mm); info->size += notesize(&info->auxv); + fill_files_note(&info->files); + info->size += notesize(&info->files); + return 1; } @@ -1611,6 +1706,8 @@ static int write_note_info(struct elf_note_info *info, return 0; if (first && !writenote(&info->auxv, file, foffset)) return 0; + if (first && !writenote(&info->files, file, foffset)) + return 0; for (i = 1; i < info->thread_notes; ++i) if (t->notes[i].data && @@ -1637,6 +1734,7 @@ static void free_note_info(struct elf_note_info *info) kfree(t); } kfree(info->psinfo.data); + vfree(info->files.data); } #else @@ -1713,7 +1811,7 @@ static int elf_note_info_init(struct elf_note_info *info) INIT_LIST_HEAD(&info->thread_list); /* Allocate space for ELF notes */ - info->notes = kmalloc(7 * sizeof(struct memelfnote), GFP_KERNEL); + info->notes = kmalloc(8 * sizeof(struct memelfnote), GFP_KERNEL); if (!info->notes) return 0; info->psinfo = kmalloc(sizeof(*info->psinfo), GFP_KERNEL); @@ -1783,10 +1881,11 @@ static int fill_note_info(struct elfhdr *elf, int phdrs, fill_note(info->notes + 1, "CORE", NT_PRPSINFO, sizeof(*info->psinfo), info->psinfo); - info->numnote = 2; + fill_siginfo_note(info->notes + 2, &info->csigdata, siginfo); + fill_auxv_note(info->notes + 3, current->mm); + fill_files_note(info->notes + 4); - fill_siginfo_note(&info->notes[info->numnote++], &info->csigdata, siginfo); - fill_auxv_note(&info->notes[info->numnote++], current->mm); + info->numnote = 5; /* Try to dump the FPU. */ info->prstatus->pr_fpvalid = elf_core_copy_task_fpregs(current, regs, @@ -1848,6 +1947,9 @@ static void free_note_info(struct elf_note_info *info) kfree(list_entry(tmp, struct elf_thread_status, list)); } + /* Free data allocated by fill_files_note(): */ + vfree(info->notes[4].data); + kfree(info->prstatus); kfree(info->psinfo); kfree(info->notes); diff --git a/fs/compat_binfmt_elf.c b/fs/compat_binfmt_elf.c index 0fbcf634743..a81147e2e4e 100644 --- a/fs/compat_binfmt_elf.c +++ b/fs/compat_binfmt_elf.c @@ -40,6 +40,7 @@ /* * Some data types as stored in coredump. */ +#define user_long_t compat_long_t #define user_siginfo_t compat_siginfo_t #define copy_siginfo_to_user copy_siginfo_to_user32 diff --git a/include/linux/elf.h b/include/linux/elf.h index dc62da7447c..59ef40650e1 100644 --- a/include/linux/elf.h +++ b/include/linux/elf.h @@ -377,6 +377,7 @@ typedef struct elf64_shdr { * in the future to accomodate more fields, don't assume it is fixed! */ #define NT_SIGINFO 0x53494749 +#define NT_FILE 0x46494c45 #define NT_PRXFPREG 0x46e62b7f /* copied from gdb5.1/include/elf/common.h */ #define NT_PPC_VMX 0x100 /* PowerPC Altivec/VMX registers */ #define NT_PPC_SPE 0x101 /* PowerPC SPE/EVR registers */