[alsa-devel] ["PATCH alsa-lib"] Change snd_dlopen() function to return the error string
Jaroslav Kysela
perex at perex.cz
Mon Nov 27 09:50:16 CET 2017
The dlopen() function might fail also for another reason than
a missing file, thus return the error string from dlerror().
Signed-off-by: Jaroslav Kysela <perex at perex.cz>
---
include/global.h | 2 +-
src/Versions.in | 5 +++++
src/conf.c | 13 ++++++-----
src/dlmisc.c | 60 +++++++++++++++++++++++++++++++++++++++----------
src/hwdep/hwdep.c | 6 ++---
src/mixer/simple_abst.c | 10 ++++-----
src/pcm/pcm_hooks.c | 8 +++----
src/pcm/pcm_meter.c | 6 ++---
src/rawmidi/rawmidi.c | 6 ++---
src/seq/seq.c | 6 ++---
src/timer/timer.c | 6 ++---
src/timer/timer_query.c | 6 ++---
12 files changed, 88 insertions(+), 46 deletions(-)
diff --git a/include/global.h b/include/global.h
index 41680829..d73d333a 100644
--- a/include/global.h
+++ b/include/global.h
@@ -97,7 +97,7 @@ extern struct snd_dlsym_link *snd_dlsym_start;
/** \brief Returns the version of a dynamic symbol as a string. */
#define SND_DLSYM_VERSION(version) __STRING(version)
-void *snd_dlopen(const char *file, int mode);
+void *snd_dlopen(const char *file, int mode, char *errbuf, size_t errbuflen);
void *snd_dlsym(void *handle, const char *name, const char *version);
int snd_dlclose(void *handle);
diff --git a/src/Versions.in b/src/Versions.in
index 8d2dd116..2f9e1697 100644
--- a/src/Versions.in
+++ b/src/Versions.in
@@ -129,3 +129,8 @@ ALSA_0.9.7 {
@SYMBOL_PREFIX at alsa_lisp_*;
} ALSA_0.9.5;
+ALSA_1.1.6 {
+ global:
+
+ @SYMBOL_PREFIX at snd_dlopen;
+} ALSA_1.1.6;
diff --git a/src/conf.c b/src/conf.c
index c410bfb8..e71bb972 100644
--- a/src/conf.c
+++ b/src/conf.c
@@ -982,6 +982,7 @@ static int get_freestring(char **string, int id, input_t *input)
case '.':
if (!id)
break;
+ /* fall through */
case ' ':
case '\f':
case '\t':
@@ -3477,7 +3478,7 @@ static int snd_config_hooks_call(snd_config_t *root, snd_config_t *config, snd_c
{
void *h = NULL;
snd_config_t *c, *func_conf = NULL;
- char *buf = NULL;
+ char *buf = NULL, errbuf[256];
const char *lib = NULL, *func_name = NULL;
const char *str;
int (*func)(snd_config_t *root, snd_config_t *config, snd_config_t **dst, snd_config_t *private_data) = NULL;
@@ -3537,11 +3538,11 @@ static int snd_config_hooks_call(snd_config_t *root, snd_config_t *config, snd_c
buf[len-1] = '\0';
func_name = buf;
}
- h = snd_dlopen(lib, RTLD_NOW);
+ h = snd_dlopen(lib, RTLD_NOW, errbuf, sizeof(errbuf));
func = h ? snd_dlsym(h, func_name, SND_DLSYM_VERSION(SND_CONFIG_DLSYM_VERSION_HOOK)) : NULL;
err = 0;
if (!h) {
- SNDERR("Cannot open shared library %s", lib);
+ SNDERR("Cannot open shared library %s (%s)", lib, errbuf);
err = -ENOENT;
} else if (!func) {
SNDERR("symbol %s is not defined inside %s", func_name, lib);
@@ -4471,7 +4472,7 @@ static int _snd_config_evaluate(snd_config_t *src,
{
int err;
if (pass == SND_CONFIG_WALK_PASS_PRE) {
- char *buf = NULL;
+ char *buf = NULL, errbuf[256];
const char *lib = NULL, *func_name = NULL;
const char *str;
int (*func)(snd_config_t **dst, snd_config_t *root,
@@ -4530,12 +4531,12 @@ static int _snd_config_evaluate(snd_config_t *src,
buf[len-1] = '\0';
func_name = buf;
}
- h = snd_dlopen(lib, RTLD_NOW);
+ h = snd_dlopen(lib, RTLD_NOW, errbuf, sizeof(errbuf));
if (h)
func = snd_dlsym(h, func_name, SND_DLSYM_VERSION(SND_CONFIG_DLSYM_VERSION_EVALUATE));
err = 0;
if (!h) {
- SNDERR("Cannot open shared library %s", lib);
+ SNDERR("Cannot open shared library %s (%s)", lib, errbuf);
err = -ENOENT;
goto _errbuf;
} else if (!func) {
diff --git a/src/dlmisc.c b/src/dlmisc.c
index f154ebd0..fca843e1 100644
--- a/src/dlmisc.c
+++ b/src/dlmisc.c
@@ -43,12 +43,18 @@ struct snd_dlsym_link *snd_dlsym_start = NULL;
* \brief Opens a dynamic library - ALSA wrapper for \c dlopen.
* \param name name of the library, similar to \c dlopen.
* \param mode mode flags, similar to \c dlopen.
+ * \param errbuf a string buffer for the error message \c dlerror.
+ * \param errbuflen a length of the string buffer for the error message.
* \return Library handle if successful, otherwise \c NULL.
*
* This function can emulate dynamic linking for the static build of
* the alsa-lib library. In that case, \p name is set to \c NULL.
*/
-void *snd_dlopen(const char *name, int mode)
+#ifndef DOXYGEN
+void *INTERNAL(snd_dlopen)(const char *name, int mode, char *errbuf, size_t errbuflen)
+#else
+void *snd_dlopen(const char *name, int mode, char *errbuf, size_t errbuflen)
+#endif
{
#ifndef PIC
if (name == NULL)
@@ -73,24 +79,49 @@ void *snd_dlopen(const char *name, int mode)
* via ld.so.conf.
*/
void *handle = NULL;
- char *filename;
+ char *filename = NULL;
if (name && name[0] != '/') {
- filename = malloc(sizeof(ALSA_PLUGIN_DIR) + 1 + strlen(name) + 1);
- strcpy(filename, ALSA_PLUGIN_DIR);
- strcat(filename, "/");
- strcat(filename, name);
- handle = dlopen(filename, mode);
- free(filename);
+ filename = alloca(sizeof(ALSA_PLUGIN_DIR) + 1 + strlen(name) + 1);
+ if (filename) {
+ strcpy(filename, ALSA_PLUGIN_DIR);
+ strcat(filename, "/");
+ strcat(filename, name);
+ handle = dlopen(filename, mode);
+ if (!handle) {
+ /* if the filename exists and cannot be opened */
+ /* return immediately */
+ if (access(filename, X_OK) == 0)
+ goto errpath;
+ }
+ }
}
- if (!handle)
+ if (!handle) {
handle = dlopen(name, mode);
+ if (!handle)
+ goto errpath;
+ }
return handle;
+errpath:
+ if (errbuf)
+ snprintf(errbuf, errbuflen, "%s: %s", filename, dlerror());
+ return NULL;
+
#else
return NULL;
#endif
}
+#ifndef DOXYGEN
+void *INTERNAL(snd_dlopen_old)(const char *name, int mode)
+{
+ return INTERNAL(snd_dlopen)(name, mode, NULL, 0);
+}
+#endif
+
+use_symbol_version(__snd_dlopen_old, snd_dlopen, ALSA_0.9);
+use_default_symbol_version(__snd_dlopen, snd_dlopen, ALSA_1.1.6);
+
/**
* \brief Closes a dynamic library - ALSA wrapper for \c dlclose.
* \param handle Library handle, similar to \c dlclose.
@@ -229,6 +260,7 @@ void *snd_dlobj_cache_get(const char *lib, const char *name,
struct list_head *p;
struct dlobj_cache *c;
void *func, *dlobj;
+ char errbuf[256];
snd_dlobj_lock();
list_for_each(p, &pcm_dlobj_list) {
@@ -247,11 +279,15 @@ void *snd_dlobj_cache_get(const char *lib, const char *name,
}
}
- dlobj = snd_dlopen(lib, RTLD_NOW);
+ errbuf[0] = '\0';
+ dlobj = snd_dlopen(lib, RTLD_NOW,
+ verbose ? errbuf : 0,
+ verbose ? sizeof(errbuf) : 0);
if (dlobj == NULL) {
if (verbose)
- SNDERR("Cannot open shared library %s",
- lib ? lib : "[builtin]");
+ SNDERR("Cannot open shared library %s (%s)",
+ lib ? lib : "[builtin]",
+ errbuf);
snd_dlobj_unlock();
return NULL;
}
diff --git a/src/hwdep/hwdep.c b/src/hwdep/hwdep.c
index 29350936..7aa475c0 100644
--- a/src/hwdep/hwdep.c
+++ b/src/hwdep/hwdep.c
@@ -41,7 +41,7 @@ static int snd_hwdep_open_conf(snd_hwdep_t **hwdep,
snd_config_t *hwdep_conf, int mode)
{
const char *str;
- char buf[256];
+ char buf[256], errbuf[256];
int err;
snd_config_t *conf, *type_conf = NULL;
snd_config_iterator_t i, next;
@@ -116,12 +116,12 @@ static int snd_hwdep_open_conf(snd_hwdep_t **hwdep,
#ifndef PIC
snd_hwdep_open_symbols();
#endif
- h = snd_dlopen(lib, RTLD_NOW);
+ h = snd_dlopen(lib, RTLD_NOW, errbuf, sizeof(errbuf));
if (h)
open_func = snd_dlsym(h, open_name, SND_DLSYM_VERSION(SND_HWDEP_DLSYM_VERSION));
err = 0;
if (!h) {
- SNDERR("Cannot open shared library %s", lib);
+ SNDERR("Cannot open shared library %s (%s)", lib, errbuf);
err = -ENOENT;
} else if (!open_func) {
SNDERR("symbol %s is not defined inside %s", open_name, lib);
diff --git a/src/mixer/simple_abst.c b/src/mixer/simple_abst.c
index 73528393..32a3f621 100644
--- a/src/mixer/simple_abst.c
+++ b/src/mixer/simple_abst.c
@@ -66,7 +66,7 @@ static int try_open(snd_mixer_class_t *class, const char *lib)
class_priv_t *priv = snd_mixer_class_get_private(class);
snd_mixer_event_t event_func;
snd_mixer_sbasic_init_t init_func = NULL;
- char *xlib, *path;
+ char *xlib, *path, errbuf[256];
void *h;
int err = 0;
@@ -81,9 +81,9 @@ static int try_open(snd_mixer_class_t *class, const char *lib)
strcpy(xlib, path);
strcat(xlib, "/");
strcat(xlib, lib);
- h = snd_dlopen(xlib, RTLD_NOW);
+ h = snd_dlopen(xlib, RTLD_NOW, errbuf, sizeof(errbuf));
if (h == NULL) {
- SNDERR("Unable to open library '%s'", xlib);
+ SNDERR("Unable to open library '%s' (%s)", xlib, errbuf);
free(xlib);
return -ENXIO;
}
@@ -114,7 +114,7 @@ static int try_open_full(snd_mixer_class_t *class, snd_mixer_t *mixer,
class_priv_t *priv = snd_mixer_class_get_private(class);
snd_mixer_event_t event_func;
snd_mixer_sfbasic_init_t init_func = NULL;
- char *xlib, *path;
+ char *xlib, *path, errbuf[256];
void *h;
int err = 0;
@@ -128,7 +128,7 @@ static int try_open_full(snd_mixer_class_t *class, snd_mixer_t *mixer,
strcat(xlib, "/");
strcat(xlib, lib);
/* note python modules requires RTLD_GLOBAL */
- h = snd_dlopen(xlib, RTLD_NOW|RTLD_GLOBAL);
+ h = snd_dlopen(xlib, RTLD_NOW|RTLD_GLOBAL, errbuf, sizeof(errbuf));
if (h == NULL) {
SNDERR("Unable to open library '%s'", xlib);
free(xlib);
diff --git a/src/pcm/pcm_hooks.c b/src/pcm/pcm_hooks.c
index adb7230b..1f08bd78 100644
--- a/src/pcm/pcm_hooks.c
+++ b/src/pcm/pcm_hooks.c
@@ -341,7 +341,7 @@ even if the specified control doesn't exist.
static int snd_pcm_hook_add_conf(snd_pcm_t *pcm, snd_config_t *root, snd_config_t *conf)
{
int err;
- char buf[256];
+ char buf[256], errbuf[256];
const char *str, *id;
const char *lib = NULL, *install = NULL;
snd_config_t *type = NULL, *args = NULL;
@@ -424,12 +424,12 @@ static int snd_pcm_hook_add_conf(snd_pcm_t *pcm, snd_config_t *root, snd_config_
install = buf;
snprintf(buf, sizeof(buf), "_snd_pcm_hook_%s_install", str);
}
- h = snd_dlopen(lib, RTLD_NOW);
+ h = snd_dlopen(lib, RTLD_NOW, errbuf, sizeof(errbuf));
install_func = h ? snd_dlsym(h, install, SND_DLSYM_VERSION(SND_PCM_DLSYM_VERSION)) : NULL;
err = 0;
if (!h) {
- SNDERR("Cannot open shared library %s",
- lib ? lib : "[builtin]");
+ SNDERR("Cannot open shared library %s (%s)",
+ lib ? lib : "[builtin]", errbuf);
err = -ENOENT;
} else if (!install_func) {
SNDERR("symbol %s is not defined inside %s", install,
diff --git a/src/pcm/pcm_meter.c b/src/pcm/pcm_meter.c
index 53685094..75df09ca 100644
--- a/src/pcm/pcm_meter.c
+++ b/src/pcm/pcm_meter.c
@@ -605,7 +605,7 @@ int snd_pcm_meter_open(snd_pcm_t **pcmp, const char *name, unsigned int frequenc
static int snd_pcm_meter_add_scope_conf(snd_pcm_t *pcm, const char *name,
snd_config_t *root, snd_config_t *conf)
{
- char buf[256];
+ char buf[256], errbuf[256];
snd_config_iterator_t i, next;
const char *id;
const char *lib = NULL, *open_name = NULL, *str = NULL;
@@ -670,11 +670,11 @@ static int snd_pcm_meter_add_scope_conf(snd_pcm_t *pcm, const char *name,
open_name = buf;
snprintf(buf, sizeof(buf), "_snd_pcm_scope_%s_open", str);
}
- h = snd_dlopen(lib, RTLD_NOW);
+ h = snd_dlopen(lib, RTLD_NOW, errbuf, sizeof(errbuf));
open_func = h ? dlsym(h, open_name) : NULL;
err = 0;
if (!h) {
- SNDERR("Cannot open shared library %s", lib);
+ SNDERR("Cannot open shared library %s (%s)", lib, errbuf);
err = -ENOENT;
} else if (!open_func) {
SNDERR("symbol %s is not defined inside %s", open_name, lib);
diff --git a/src/rawmidi/rawmidi.c b/src/rawmidi/rawmidi.c
index 7180becd..88d43017 100644
--- a/src/rawmidi/rawmidi.c
+++ b/src/rawmidi/rawmidi.c
@@ -162,7 +162,7 @@ static int snd_rawmidi_open_conf(snd_rawmidi_t **inputp, snd_rawmidi_t **outputp
snd_config_t *rawmidi_conf, int mode)
{
const char *str;
- char buf[256];
+ char buf[256], errbuf[256];
int err;
snd_config_t *conf, *type_conf = NULL;
snd_config_iterator_t i, next;
@@ -239,12 +239,12 @@ static int snd_rawmidi_open_conf(snd_rawmidi_t **inputp, snd_rawmidi_t **outputp
#ifndef PIC
snd_rawmidi_open_symbols();
#endif
- h = snd_dlopen(lib, RTLD_NOW);
+ h = snd_dlopen(lib, RTLD_NOW, errbuf, sizeof(errbuf));
if (h)
open_func = snd_dlsym(h, open_name, SND_DLSYM_VERSION(SND_RAWMIDI_DLSYM_VERSION));
err = 0;
if (!h) {
- SNDERR("Cannot open shared library %s", lib);
+ SNDERR("Cannot open shared library %s (%s)", lib, errbuf);
err = -ENOENT;
} else if (!open_func) {
SNDERR("symbol %s is not defined inside %s", open_name, lib);
diff --git a/src/seq/seq.c b/src/seq/seq.c
index 630f52c3..983c4fab 100644
--- a/src/seq/seq.c
+++ b/src/seq/seq.c
@@ -823,7 +823,7 @@ static int snd_seq_open_conf(snd_seq_t **seqp, const char *name,
int streams, int mode)
{
const char *str;
- char buf[256];
+ char buf[256], errbuf[256];
int err;
snd_config_t *conf, *type_conf = NULL;
snd_config_iterator_t i, next;
@@ -899,12 +899,12 @@ static int snd_seq_open_conf(snd_seq_t **seqp, const char *name,
#ifndef PIC
snd_seq_open_symbols();
#endif
- h = snd_dlopen(lib, RTLD_NOW);
+ h = snd_dlopen(lib, RTLD_NOW, errbuf, sizeof(errbuf));
if (h)
open_func = snd_dlsym(h, open_name, SND_DLSYM_VERSION(SND_SEQ_DLSYM_VERSION));
err = 0;
if (!h) {
- SNDERR("Cannot open shared library %s", lib);
+ SNDERR("Cannot open shared library %s (%s)", lib, errbuf);
err = -ENOENT;
} else if (!open_func) {
SNDERR("symbol %s is not defined inside %s", open_name, lib);
diff --git a/src/timer/timer.c b/src/timer/timer.c
index e027c903..8c49737e 100644
--- a/src/timer/timer.c
+++ b/src/timer/timer.c
@@ -76,7 +76,7 @@ static int snd_timer_open_conf(snd_timer_t **timer,
snd_config_t *timer_conf, int mode)
{
const char *str;
- char buf[256];
+ char buf[256], errbuf[256];
int err;
snd_config_t *conf, *type_conf = NULL;
snd_config_iterator_t i, next;
@@ -150,12 +150,12 @@ static int snd_timer_open_conf(snd_timer_t **timer,
#ifndef PIC
snd_timer_open_symbols();
#endif
- h = snd_dlopen(lib, RTLD_NOW);
+ h = snd_dlopen(lib, RTLD_NOW, errbuf, sizeof(errbuf));
if (h)
open_func = snd_dlsym(h, open_name, SND_DLSYM_VERSION(SND_TIMER_DLSYM_VERSION));
err = 0;
if (!h) {
- SNDERR("Cannot open shared library %s", lib);
+ SNDERR("Cannot open shared library %s (%s)", lib, errbuf);
err = -ENOENT;
} else if (!open_func) {
SNDERR("symbol %s is not defined inside %s", open_name, lib);
diff --git a/src/timer/timer_query.c b/src/timer/timer_query.c
index d999d21b..6739f3c4 100644
--- a/src/timer/timer_query.c
+++ b/src/timer/timer_query.c
@@ -33,7 +33,7 @@ static int snd_timer_query_open_conf(snd_timer_query_t **timer,
snd_config_t *timer_conf, int mode)
{
const char *str;
- char buf[256];
+ char buf[256], errbuf[256];
int err;
snd_config_t *conf, *type_conf = NULL;
snd_config_iterator_t i, next;
@@ -108,12 +108,12 @@ static int snd_timer_query_open_conf(snd_timer_query_t **timer,
#ifndef PIC
snd_timer_query_open_symbols();
#endif
- h = snd_dlopen(lib, RTLD_NOW);
+ h = snd_dlopen(lib, RTLD_NOW, errbuf, sizeof(errbuf));
if (h)
open_func = snd_dlsym(h, open_name, SND_DLSYM_VERSION(SND_TIMER_QUERY_DLSYM_VERSION));
err = 0;
if (!h) {
- SNDERR("Cannot open shared library %s", lib);
+ SNDERR("Cannot open shared library %s (%s)", lib, errbuf);
err = -ENOENT;
} else if (!open_func) {
SNDERR("symbol %s is not defined inside %s", open_name, lib);
--
2.13.6
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