closes bpo-42030: Remove legacy AIX dynload support (GH-22717)

Since c19c5a6, AIX builds have defaulted to using dynload_shlib over
dynload_aix when dlopen is available. This function has been available
since AIX 4.3, which went out of support in 2003, the same year the
previously referenced commit was made. It has been nearly 20 years
since a version of AIX has been supported which has not used
dynload_shlib so there's no reason to keep this legacy code around.

4 files changed, 3 insertions, 202 deletions

diff --git a/Misc/NEWS.d/next/Core and Builtins/2020-10-15-21-55-32.bpo-42030.PmU2CA.rst b/Misc/NEWS.d/next/Core and Builtins/2020-10-15-21-55-32.bpo-42030.PmU2CA.rst
new file mode 100644
index 00000000000..e8c691d8096
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2020-10-15-21-55-32.bpo-42030.PmU2CA.rst
@@ -0,0 +1,3 @@
+Support for the legacy AIX-specific shared library loading support has been
+removed. All versions of AIX since 4.3 have supported and defaulted to using
+the common Unix mechanism instead.
diff --git a/Python/dynload_aix.c b/Python/dynload_aix.c
deleted file mode 100644
index 97f7698ef4b..00000000000
--- a/Python/dynload_aix.c
+++ /dev/null
@@ -1,190 +0,0 @@
-
-/* Support for dynamic loading of extension modules */
-
-#include "Python.h"
-#include "importdl.h"
-
-#include <errno.h>      /*  for global errno      */
-#include <string.h>     /*  for strerror()        */
-#include <stdlib.h>     /*  for malloc(), free()  */
-#include <sys/ldr.h>
-
-
-#ifdef AIX_GENUINE_CPLUSPLUS
-#include <load.h>
-#define aix_load loadAndInit
-#else
-#define aix_load load
-#endif
-
-
-extern char *Py_GetProgramName(void);
-
-typedef struct Module {
-    struct Module *next;
-    void          *entry;
-} Module, *ModulePtr;
-
-const char *_PyImport_DynLoadFiletab[] = {".so", NULL};
-
-static int
-aix_getoldmodules(void **modlistptr)
-{
-    ModulePtr       modptr, prevmodptr;
-    struct ld_info  *ldiptr;
-    char            *ldibuf;
-    int             errflag, bufsize = 1024;
-    unsigned int    offset;
-    char *progname = Py_GetProgramName();
-
-    /*
-    -- Get the list of loaded modules into ld_info structures.
-    */
-    if ((ldibuf = malloc(bufsize)) == NULL) {
-        PyErr_SetString(PyExc_ImportError, strerror(errno));
-        return -1;
-    }
-    while ((errflag = loadquery(L_GETINFO, ldibuf, bufsize)) == -1
-           && errno == ENOMEM) {
-        free(ldibuf);
-        bufsize += 1024;
-        if ((ldibuf = malloc(bufsize)) == NULL) {
-            PyErr_SetString(PyExc_ImportError, strerror(errno));
-            return -1;
-        }
-    }
-    if (errflag == -1) {
-        PyErr_SetString(PyExc_ImportError, strerror(errno));
-        return -1;
-    }
-    /*
-    -- Make the modules list from the ld_info structures.
-    */
-    ldiptr = (struct ld_info *)ldibuf;
-    prevmodptr = NULL;
-    do {
-        if (strstr(progname, ldiptr->ldinfo_filename) == NULL &&
-            strstr(ldiptr->ldinfo_filename, "python") == NULL) {
-            /*
-            -- Extract only the modules belonging to the main
-            -- executable + those containing "python" as a
-            -- substring (like the "python[version]" binary or
-            -- "libpython[version].a" in case it's a shared lib).
-            */
-            offset = (unsigned int)ldiptr->ldinfo_next;
-            ldiptr = (struct ld_info *)((char*)ldiptr + offset);
-            continue;
-        }
-        if ((modptr = (ModulePtr)malloc(sizeof(Module))) == NULL) {
-            PyErr_SetString(PyExc_ImportError, strerror(errno));
-            while (*modlistptr) {
-                modptr = (ModulePtr)*modlistptr;
-                *modlistptr = (void *)modptr->next;
-                free(modptr);
-            }
-            return -1;
-        }
-        modptr->entry = ldiptr->ldinfo_dataorg;
-        modptr->next  = NULL;
-        if (prevmodptr == NULL)
-            *modlistptr = (void *)modptr;
-        else
-            prevmodptr->next = modptr;
-        prevmodptr = modptr;
-        offset = (unsigned int)ldiptr->ldinfo_next;
-        ldiptr = (struct ld_info *)((char*)ldiptr + offset);
-    } while (offset);
-    free(ldibuf);
-    return 0;
-}
-
-
-static void
-aix_loaderror(const char *pathname)
-{
-
-    char *message[1024], errbuf[1024];
-    PyObject *pathname_ob = NULL;
-    PyObject *errbuf_ob = NULL;
-    int i,j;
-
-    struct errtab {
-        int errNo;
-        char *errstr;
-    } load_errtab[] = {
-        {L_ERROR_TOOMANY,               "too many errors, rest skipped."},
-        {L_ERROR_NOLIB,                 "can't load library:"},
-        {L_ERROR_UNDEF,                 "can't find symbol in library:"},
-        {L_ERROR_RLDBAD,
-         "RLD index out of range or bad relocation type:"},
-        {L_ERROR_FORMAT,                "not a valid, executable xcoff file:"},
-        {L_ERROR_MEMBER,
-         "file not an archive or does not contain requested member:"},
-        {L_ERROR_TYPE,                  "symbol table mismatch:"},
-        {L_ERROR_ALIGN,                 "text alignment in file is wrong."},
-        {L_ERROR_SYSTEM,                "System error:"},
-        {L_ERROR_ERRNO,                 NULL}
-    };
-
-#define ERRBUF_APPEND(s) strncat(errbuf, s, sizeof(errbuf)-strlen(errbuf)-1)
-
-    PyOS_snprintf(errbuf, sizeof(errbuf), "from module %.200s ", pathname);
-
-    if (!loadquery(L_GETMESSAGES, &message[0], sizeof(message))) {
-        ERRBUF_APPEND(strerror(errno));
-        ERRBUF_APPEND("\n");
-    }
-    for(i = 0; message[i] && *message[i]; i++) {
-        int nerr = atoi(message[i]);
-        for (j=0; j < Py_ARRAY_LENGTH(load_errtab); j++) {
-            if (nerr == load_errtab[j].errNo && load_errtab[j].errstr)
-            ERRBUF_APPEND(load_errtab[j].errstr);
-        }
-        while (Py_ISDIGIT(*message[i])) message[i]++ ;
-        ERRBUF_APPEND(message[i]);
-        ERRBUF_APPEND("\n");
-    }
-    /* Subtract 1 from the length to trim off trailing newline */
-    errbuf_ob = PyUnicode_DecodeLocaleAndSize(errbuf, strlen(errbuf)-1, "surrogateescape");
-    if (errbuf_ob == NULL)
-        return;
-    pathname_ob = PyUnicode_DecodeFSDefault(pathname);
-    if (pathname_ob == NULL) {
-        Py_DECREF(errbuf_ob);
-        return;
-    }
-    PyErr_SetImportError(errbuf_ob, NULL, pathname_ob);
-    Py_DECREF(pathname_ob);
-    Py_DECREF(errbuf_ob);
-    return;
-}
-
-
-dl_funcptr _PyImport_FindSharedFuncptr(const char *prefix,
-                                       const char *shortname,
-                                       const char *pathname, FILE *fp)
-{
-    dl_funcptr p;
-
-    /*
-    -- Invoke load() with L_NOAUTODEFER leaving the imported symbols
-    -- of the shared module unresolved. Thus we have to resolve them
-    -- explicitly with loadbind. The new module is loaded, then we
-    -- resolve its symbols using the list of already loaded modules
-    -- (only those that belong to the python executable). Get these
-    -- with loadquery(L_GETINFO).
-    */
-
-    static void *staticmodlistptr = NULL;
-
-    if (!staticmodlistptr)
-        if (aix_getoldmodules(&staticmodlistptr) == -1)
-            return NULL;
-    p = (dl_funcptr) aix_load((char *)pathname, L_NOAUTODEFER, 0);
-    if (p == NULL) {
-        aix_loaderror(pathname);
-        return NULL;
-    }
-
-    return p;
-}
diff --git a/configure b/configure
index 89577d85a41..88b78947767 100755
--- a/configure
+++ b/configure
@@ -11625,12 +11625,6 @@ $as_echo_n "checking DYNLOADFILE... " >&6; }
 if test -z "$DYNLOADFILE"
 then
 	case $ac_sys_system/$ac_sys_release in
-	AIX*) # Use dynload_shlib.c and dlopen() if we have it; otherwise dynload_aix.c
-	if test "$ac_cv_func_dlopen" = yes
-	then DYNLOADFILE="dynload_shlib.o"
-	else DYNLOADFILE="dynload_aix.o"
-	fi
-	;;
 	hp*|HP*) DYNLOADFILE="dynload_hpux.o";;
 	*)
 	# use dynload_shlib.c and dlopen() if we have it; otherwise stub
diff --git a/configure.ac b/configure.ac
index 3ec274c576e..6ffe90a4c42 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3622,12 +3622,6 @@ AC_MSG_CHECKING(DYNLOADFILE)
 if test -z "$DYNLOADFILE"
 then
 	case $ac_sys_system/$ac_sys_release in
-	AIX*) # Use dynload_shlib.c and dlopen() if we have it; otherwise dynload_aix.c
-	if test "$ac_cv_func_dlopen" = yes
-	then DYNLOADFILE="dynload_shlib.o"
-	else DYNLOADFILE="dynload_aix.o"
-	fi
-	;;
 	hp*|HP*) DYNLOADFILE="dynload_hpux.o";;
 	*)
 	# use dynload_shlib.c and dlopen() if we have it; otherwise stub