[med-svn] [htslib] 03/06: Allow plugins to select RTLD_LOCAL or RTLD_GLOBAL

[Andreas Tille]

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tille pushed a commit to branch debian/unstable
in repository htslib.

commit ebdb5aa584e8160d105e311619b0a12ac3e5a737
Author: John Marshall <jm18 at sanger.ac.uk>
Date:   Thu Jul 28 16:54:44 2016 +0100

    Allow plugins to select RTLD_LOCAL or RTLD_GLOBAL
    
    If the plugin does not provide the requested symbol, fall back to
    reopening it with RTLD_GLOBAL and searching for a uniquified symbol,
    <symbol>_<filename_basename>.
    
    Most plugins should work with RTLD_LOCAL, but occasionally RTLD_GLOBAL
    is needed.  For example, with iRODS 4.1.x, iRODS itself has plugins
    (libtcp.so et al) that need to resolve iRODS symbols linked into
    whatever is invoking it, i.e., HTSlib's hFILE plugin.
    
    (cherry picked from commit 344c82579a8d56d1f92c8073c71037b99beb13cb)
---
 plugin.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/plugin.c b/plugin.c
index 7525cc6..aaa965f 100644
--- a/plugin.c
+++ b/plugin.c
@@ -135,13 +135,35 @@ const char *hts_path_itr_next(struct hts_path_itr *itr)
     return NULL;
 }
 
+
+#ifndef RTLD_NOLOAD
+#define RTLD_NOLOAD 0
+#endif
+
 void *load_plugin(void **pluginp, const char *filename, const char *symbol)
 {
     void *lib = dlopen(filename, RTLD_NOW | RTLD_LOCAL);
     if (lib == NULL) goto error;
 
     void *sym = dlsym(lib, symbol);
-    if (sym == NULL) goto error;
+    if (sym == NULL) {
+        // Reopen the plugin with RTLD_GLOBAL and check for uniquified symbol
+        void *libg = dlopen(filename, RTLD_NOLOAD | RTLD_NOW | RTLD_GLOBAL);
+        if (libg == NULL) goto error;
+        dlclose(lib);
+        lib = libg;
+
+        kstring_t symbolg = { 0, 0, NULL };
+        kputs(symbol, &symbolg);
+        kputc('_', &symbolg);
+        const char *slash = strrchr(filename, '/');
+        const char *basename = slash? slash+1 : filename;
+        kputsn(basename, strcspn(basename, ".-+"), &symbolg);
+
+        sym = dlsym(lib, symbolg.s);
+        free(symbolg.s);
+        if (sym == NULL) goto error;
+    }
 
     *pluginp = lib;
     return sym;

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