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>

1 files changed, 23 insertions, 37 deletions

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 501c8a4d6eb1..00fd9c969a27 100644
--- 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;