diff options
Diffstat (limited to 'libdw/dwarf_getpubnames.c')
| -rw-r--r-- | libdw/dwarf_getpubnames.c | 40 |
1 files changed, 32 insertions, 8 deletions
diff --git a/libdw/dwarf_getpubnames.c b/libdw/dwarf_getpubnames.c index 1b054e26..a0ac6fba 100644 --- a/libdw/dwarf_getpubnames.c +++ b/libdw/dwarf_getpubnames.c @@ -179,16 +179,34 @@ dwarf_getpubnames (dbg, callback, arg, offset) return -1l; } + /* If we are going to call get_offsets, we will likely need write + lock. Take it right away so that we don't have to go through the + fuss of lock upgrading later. That means we need to read from + dbg before having locked, but we need to do that for dbg->lock + anyway. The worst that can happen is we accidentally take wrlock + where rdlock would have sufficed. + + Note that we can do so specifically in this case, where we don't + call anything that would downgrade the lock back to rdlock. */ + if (dbg->pubnames_nsets == 0) + rwlock_wrlock (dbg->lock); + else + rwlock_rdlock (dbg->lock); + ptrdiff_t retval = 0l; + /* Make sure it is a valid offset. */ if (unlikely (dbg->sectiondata[IDX_debug_pubnames] == NULL || ((size_t) offset >= dbg->sectiondata[IDX_debug_pubnames]->d_size))) /* No (more) entry. */ - return 0; + goto out; /* If necessary read the set information. */ if (dbg->pubnames_nsets == 0 && unlikely (get_offsets (dbg) != 0)) - return -1l; + { + retval = -1l; + goto out; + } /* Find the place where to start. */ size_t cnt; @@ -238,12 +256,16 @@ dwarf_getpubnames (dbg, callback, arg, offset) readp = (unsigned char *) rawmemchr (gl.name, '\0') + 1; /* We found name and DIE offset. Report it. */ + /* Give up the lock, so that the callback can use official + (locking) API. We can afford to do that: references + above are to write-once caches. */ + rwlock_unlock (dbg->lock); if (callback (dbg, &gl, arg) != DWARF_CB_OK) - { - /* The user wants us to stop. Return the offset of the - next entry. */ - return readp - startp; - } + /* The user wants us to stop. Return the offset of the + next entry. */ + return readp - startp; + /* rdlock is enough at this point. */ + rwlock_rdlock (dbg->lock); } if (++cnt == dbg->pubnames_nsets) @@ -255,5 +277,7 @@ dwarf_getpubnames (dbg, callback, arg, offset) } /* We are done. No more entries. */ - return 0; + out: + rwlock_unlock (dbg->lock); + return retval; } |