new helper: dump_emit()

dump_write() analog, takes core_dump_params instead of file,
keeps track of the amount written in cprm->written and checks for
cprm->limit.  Start using it in binfmt_elf.c...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 501c8a4d6eb1cb1bb3753da7f3aa0ae41a0ef36a..00fd9c969a2716e04f387277fdc88c49afe5ebce 100644 (file)
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1225,35 +1225,23 @@ static int notesize(struct memelfnote *en)
        return sz;
 }
 
-#define DUMP_WRITE(addr, nr, foffset)  \
-       do { if (!dump_write(file, (addr), (nr))) return 0; *foffset += (nr); } while(0)
-
-static int alignfile(struct file *file, loff_t *foffset)
+static int alignfile(struct coredump_params *cprm)
 {
        static const char buf[4] = { 0, };
-       DUMP_WRITE(buf, roundup(*foffset, 4) - *foffset, foffset);
-       return 1;
+       return dump_emit(cprm, buf, roundup(cprm->written, 4) - cprm->written);
 }
 
-static int writenote(struct memelfnote *men, struct file *file,
-                       loff_t *foffset)
+static int writenote(struct memelfnote *men, struct coredump_params *cprm)
 {
        struct elf_note en;
        en.n_namesz = strlen(men->name) + 1;
        en.n_descsz = men->datasz;
        en.n_type = men->type;
 
-       DUMP_WRITE(&en, sizeof(en), foffset);
-       DUMP_WRITE(men->name, en.n_namesz, foffset);
-       if (!alignfile(file, foffset))
-               return 0;
-       DUMP_WRITE(men->data, men->datasz, foffset);
-       if (!alignfile(file, foffset))
-               return 0;
-
-       return 1;
+       return dump_emit(cprm, &en, sizeof(en)) &&
+           dump_emit(cprm, men->name, en.n_namesz) && alignfile(cprm) &&
+           dump_emit(cprm, men->data, men->datasz) && alignfile(cprm);
 }
-#undef DUMP_WRITE
 
 static void fill_elf_header(struct elfhdr *elf, int segs,
                            u16 machine, u32 flags)
@@ -1702,7 +1690,7 @@ static size_t get_note_info_size(struct elf_note_info *info)
  * process-wide notes are interleaved after the first thread-specific note.
  */
 static int write_note_info(struct elf_note_info *info,
-                          struct file *file, loff_t *foffset)
+                          struct coredump_params *cprm)
 {
        bool first = 1;
        struct elf_thread_core_info *t = info->thread;
@@ -1710,22 +1698,22 @@ static int write_note_info(struct elf_note_info *info,
        do {
                int i;
 
-               if (!writenote(&t->notes[0], file, foffset))
+               if (!writenote(&t->notes[0], cprm))
                        return 0;
 
-               if (first && !writenote(&info->psinfo, file, foffset))
+               if (first && !writenote(&info->psinfo, cprm))
                        return 0;
-               if (first && !writenote(&info->signote, file, foffset))
+               if (first && !writenote(&info->signote, cprm))
                        return 0;
-               if (first && !writenote(&info->auxv, file, foffset))
+               if (first && !writenote(&info->auxv, cprm))
                        return 0;
                if (first && info->files.data &&
-                               !writenote(&info->files, file, foffset))
+                               !writenote(&info->files, cprm))
                        return 0;
 
                for (i = 1; i < info->thread_notes; ++i)
                        if (t->notes[i].data &&
-                           !writenote(&t->notes[i], file, foffset))
+                           !writenote(&t->notes[i], cprm))
                                return 0;
 
                first = 0;
@@ -1935,13 +1923,13 @@ static size_t get_note_info_size(struct elf_note_info *info)
 }
 
 static int write_note_info(struct elf_note_info *info,
-                          struct file *file, loff_t *foffset)
+                          struct coredump_params *cprm)
 {
        int i;
        struct list_head *t;
 
        for (i = 0; i < info->numnote; i++)
-               if (!writenote(info->notes + i, file, foffset))
+               if (!writenote(info->notes + i, cprm))
                        return 0;
 
        /* write out the thread status notes section */
@@ -1950,7 +1938,7 @@ static int write_note_info(struct elf_note_info *info,
                                list_entry(t, struct elf_thread_status, list);
 
                for (i = 0; i < tmp->num_notes; i++)
-                       if (!writenote(&tmp->notes[i], file, foffset))
+                       if (!writenote(&tmp->notes[i], cprm))
                                return 0;
        }
 
@@ -2136,13 +2124,10 @@ static int elf_core_dump(struct coredump_params *cprm)
 
        offset = dataoff;
 
-       size += sizeof(*elf);
-       if (size > cprm->limit || !dump_write(cprm->file, elf, sizeof(*elf)))
+       if (!dump_emit(cprm, elf, sizeof(*elf)))
                goto end_coredump;
 
-       size += sizeof(*phdr4note);
-       if (size > cprm->limit
-           || !dump_write(cprm->file, phdr4note, sizeof(*phdr4note)))
+       if (!dump_emit(cprm, phdr4note, sizeof(*phdr4note)))
                goto end_coredump;
 
        /* Write program headers for segments dump */
@@ -2164,19 +2149,20 @@ static int elf_core_dump(struct coredump_params *cprm)
                        phdr.p_flags |= PF_X;
                phdr.p_align = ELF_EXEC_PAGESIZE;
 
-               size += sizeof(phdr);
-               if (size > cprm->limit
-                   || !dump_write(cprm->file, &phdr, sizeof(phdr)))
+               if (!dump_emit(cprm, &phdr, sizeof(phdr)))
                        goto end_coredump;
        }
+       size = cprm->written;
 
        if (!elf_core_write_extra_phdrs(cprm->file, offset, &size, cprm->limit))
                goto end_coredump;
 
+       cprm->written = foffset;        /* will disappear */
        /* write out the notes section */
-       if (!write_note_info(&info, cprm->file, &foffset))
+       if (!write_note_info(&info, cprm))
                goto end_coredump;
 
+       foffset = cprm->written;
        if (elf_coredump_extra_notes_write(cprm->file, &foffset))
                goto end_coredump;
 

diff --git a/fs/coredump.c b/fs/coredump.c
index 42c3b842366980bcdb12dae8eace880464c50cd4..319f973bab729cc875ede0f7fa217434e0512e78 100644 (file)
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -693,6 +693,20 @@ int dump_write(struct file *file, const void *addr, int nr)
 }
 EXPORT_SYMBOL(dump_write);
 
+int dump_emit(struct coredump_params *cprm, const void *addr, int nr)
+{
+       struct file *file = cprm->file;
+       if (dump_interrupted() || !access_ok(VERIFY_READ, addr, nr))
+               return 0;
+       if (cprm->written + nr > cprm->limit)
+               return 0;
+       if (file->f_op->write(file, addr, nr, &file->f_pos) != nr)
+               return 0;
+       cprm->written += nr;
+       return 1;
+}
+EXPORT_SYMBOL(dump_emit);
+
 int dump_seek(struct file *file, loff_t off)
 {
        int ret = 1;

diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h
index e8112ae5053131c47a1e472985fc1628ddd5e8eb..8aa507e7a41a8a1c99fcd1469086c9e60b6a9e50 100644 (file)
--- a/include/linux/binfmts.h
+++ b/include/linux/binfmts.h
@@ -61,6 +61,7 @@ struct coredump_params {
        struct file *file;
        unsigned long limit;
        unsigned long mm_flags;
+       loff_t written;
 };
 
 /*

diff --git a/include/linux/coredump.h b/include/linux/coredump.h
index a98f1ca60407d574ee89980bde8029d8f1f73f78..2959376a9ad525f3b722ab233e5960d2104a0751 100644 (file)
--- a/include/linux/coredump.h
+++ b/include/linux/coredump.h
@@ -10,8 +10,10 @@
  * These are the only things you should do on a core-file: use only these
  * functions to write out all the necessary info.
  */
+struct coredump_params;
 extern int dump_write(struct file *file, const void *addr, int nr);
 extern int dump_seek(struct file *file, loff_t off);
+extern int dump_emit(struct coredump_params *cprm, const void *addr, int nr);
 #ifdef CONFIG_COREDUMP
 extern void do_coredump(siginfo_t *siginfo);
 #else