1 files changed, 96 insertions, 0 deletions
diff --git a/src/libps/s6ps_wchan.c b/src/libps/s6ps_wchan.c
new file mode 100644
index 0000000..9261693
--- /dev/null
+++ b/src/libps/s6ps_wchan.c
@@ -0,0 +1,96 @@
+/* ISC license. */
+
+#include <string.h>
+#include <sys/utsname.h>
+
+#include <skalibs/uint64.h>
+#include <skalibs/stralloc.h>
+#include <skalibs/genalloc.h>
+#include <skalibs/djbunix.h>
+
+#include "s6-ps.h"
+
+static stralloc sysmap = STRALLOC_ZERO ;
+static genalloc ind = GENALLOC_ZERO ;
+
+int s6ps_wchan_init (char const *file)
+{
+  if (file)
+  {
+    if (!openslurpclose(&sysmap, file)) return 0 ;
+  }
+  else
+  {
+    char *files[3] = { "/proc/kallsyms", 0, "/boot/System.map" } ;
+    struct utsname uts ;
+    size_t n ;
+    if (uname(&uts) < 0) return 0 ;
+    n = strlen(uts.release) ;
+    {
+      char buf[18 + n] ;
+      unsigned int i = 0 ;
+      memcpy(buf, "/boot/System.map", 16) ;
+      buf[16] = '-' ;
+      memcpy(buf + 17, uts.release, n + 1) ;
+      files[1] = buf ;
+      for (; i < 3 ; i++)
+        if (openslurpclose(&sysmap, files[i])) break ;
+      if (i >= 3) return 0 ;
+    }
+  }
+  {
+    size_t i = 0 ;
+    if (!genalloc_append(size_t, &ind, &i)) goto err2 ;
+    for (i = 1 ; i <= sysmap.len ; i++)
+      if (sysmap.s[i-1] == '\n')
+        if (!genalloc_append(size_t, &ind, &i)) goto err ;
+  }
+  return 1 ;
+ err:
+  genalloc_free(size_t, &ind) ;
+ err2:
+  stralloc_free(&sysmap) ;
+  return 0 ;
+}
+
+void s6ps_wchan_finish (void)
+{
+  genalloc_free(size_t, &ind) ;
+  stralloc_free(&sysmap) ;
+}
+
+static inline size_t lookup (uint64_t addr, size_t *i)
+{
+  size_t low = 0, mid, high = genalloc_len(size_t, &ind), len ;
+  for (;;)
+  {
+    uint64_t cur ;
+    mid = (low + high) >> 1 ;
+    len = uint64_xscan(sysmap.s + genalloc_s(size_t, &ind)[mid], &cur) ;
+    if (!len) return 0 ;
+    if (cur == addr) break ;
+    if (mid == low) return 0 ;
+    if (addr < cur) high = mid ; else low = mid ;
+  }
+  *i = mid ;
+  return len ;
+}
+
+int s6ps_wchan_lookup (stralloc *sa, uint64_t addr)
+{
+  if (addr == (sizeof(void *) == 8 ? 0xffffffffffffffffULL : 0xffffffffUL))
+    return stralloc_catb(sa, "*", 1) ;
+  if (!addr) return stralloc_catb(sa, "-", 1) ;
+  if (sysmap.len)
+  {
+    size_t i, pos, len = lookup(addr, &i) ;
+    if (!len) return stralloc_catb(sa, "?", 1) ;
+    pos = genalloc_s(size_t, &ind)[i] + len + 3 ;
+    return stralloc_catb(sa, sysmap.s + pos, genalloc_s(size_t, &ind)[i+1] - 1 - pos) ;
+  }
+  if (!stralloc_readyplus(sa, UINT64_FMT + 3)) return 0 ;
+  stralloc_catb(sa, "(0x", 3) ;
+  sa->len += uint64_fmt(sa->s + sa->len, addr) ;
+  stralloc_catb(sa, ")", 1) ;
+  return 1 ;
+}