snd_dlopen: implement the relocatable version for glibc

BugLink: https://github.com/alsa-project/alsa-lib/issues/34
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
This commit is contained in:
Jaroslav Kysela 2020-06-04 19:06:08 +02:00
parent b2a4272ecb
commit 33089f30a3
3 changed files with 50 additions and 9 deletions

View file

@ -32,6 +32,7 @@
#ifdef HAVE_LIBPTHREAD
#include <pthread.h>
#endif
#include <limits.h>
#ifndef DOC_HIDDEN
#ifndef PIC
@ -39,6 +40,42 @@ struct snd_dlsym_link *snd_dlsym_start = NULL;
#endif
#endif
/**
*
* \brief Compose the dynamic path
* \param path Returned path (string)
* \param path_len Returned path max size (with trailing zero)
* \param name Plugin name (relative)
* \return Zero on success, otherwise a negative error code
*/
int snd_dlpath(char *path, size_t path_len, const char *name)
{
static const char *origin_dir = NULL;
#ifdef HAVE_LIBDL
#ifdef __GLIBC__
static int plugin_dir_set = 0;
if (!plugin_dir_set) {
struct link_map *links;
Dl_info info;
char origin[PATH_MAX];
if (dladdr1(&snd_dlpath, &info, (void**)&links, RTLD_DL_LINKMAP) == 0)
links = NULL;
if (links != NULL && dlinfo(links, RTLD_DI_ORIGIN, origin) == 0) {
snprintf(path, path_len, "%s/alsa-lib", origin);
if (access(path, X_OK) == 0)
origin_dir = origin;
}
plugin_dir_set = 1;
}
#endif
#endif
if (origin_dir)
snprintf(path, path_len, "%s/alsa-lib/%s", origin_dir, name);
else
snprintf(path, path_len, "%s/%s", ALSA_PLUGIN_DIR, name);
return 0;
}
/**
* \brief Opens a dynamic library - ALSA wrapper for \c dlopen.
* \param name name of the library, similar to \c dlopen.
@ -79,14 +116,12 @@ void *snd_dlopen(const char *name, int mode, char *errbuf, size_t errbuflen)
* via ld.so.conf.
*/
void *handle = NULL;
char *filename = NULL;
const char *filename = NULL;
char path[PATH_MAX];
if (name && name[0] != '/') {
filename = alloca(sizeof(ALSA_PLUGIN_DIR) + 1 + strlen(name) + 1);
if (filename) {
strcpy(filename, ALSA_PLUGIN_DIR);
strcat(filename, "/");
strcat(filename, name);
if (snd_dlpath(path, sizeof(path), name) == 0) {
filename = name;
handle = dlopen(filename, mode);
if (!handle) {
/* if the filename exists and cannot be opened */
@ -97,6 +132,7 @@ void *snd_dlopen(const char *name, int mode, char *errbuf, size_t errbuflen)
}
}
if (!handle) {
filename = name;
handle = dlopen(name, mode);
if (!handle)
goto errpath;