Complete Linux/Complete Linux.iso/docs/apps/database/postgres/postgre4.z/postgre4/src/port/seq/dynloader.c

C/C++ Source or Header | 1992-08-27 | 4.6 KB | 227 lines

/*

!!!! Be sure that we close all open files up exit on the Sequent - the ld !!!!
     fails otherwise

     $Header: /private/postgres/src/port/seq/RCS/dynloader.c,v 1.18 1992/01/12 23:28:30 mao Exp $
*/

#include <pwd.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/file.h>

extern char pg_pathname[];

#include <a.out.h>

#include "tmp/c.h"
#include "utils/fmgr.h"

/*
 * Allow extra space for "overruns" caused by the link.
 */

#define FUDGE 10000

static char *temp_file_name = NULL;
static char *path = "/usr/tmp/postgres";

DynamicFunctionList *
dynamic_file_load(err, filename, address, size)

char **err, *filename, **address;
long *size;

{
    extern char *valloc();

    int nread;
    struct exec ld_header, header;
    unsigned long image_size, true_image_size;
    char *load_address = NULL;
    FILE *temp_file = NULL;
    DynamicFunctionList *retval = NULL, *load_symbols();
    int fd;
    char foo[10];

    closeAllVfds(); /* We run out of open files in running on the Sequent */

    fd = open(filename, O_RDONLY);


    if (fd == -1)
    {
        *err = "error opening file";
        goto finish_up;
    }

    read(fd, &ld_header, sizeof(struct exec));

    image_size = ld_header.a_text + ld_header.a_data + ld_header.a_bss + FUDGE;

    close(fd); /* don't open it until the load is finished. */

    if (!(load_address = valloc(image_size)))
    {
        *err = "unable to allocate memory";
        goto finish_up;
    }

    if (temp_file_name == NULL)
    {
        sprintf(foo, "%d", getpid());
        temp_file_name = (char *)malloc(strlen(path) + strlen(foo) + 2);
        strcpy(temp_file_name, path);
        strcat(temp_file_name, foo);
    }

    if(execld(load_address, temp_file_name, filename))
    {
        *err = "link failed!";
        goto finish_up;
    }

    if(!(temp_file = fopen(temp_file_name,"r")))
    {
        *err = "unable to open tmp file";
        goto finish_up;
    }
    nread = fread(&header, sizeof(header), 1, temp_file);
    true_image_size = header.a_text + header.a_data + header.a_bss;

    if (true_image_size > image_size)
    {
        fclose(temp_file);
        free(load_address);
        load_address = valloc(true_image_size);

        if (execld(load_address, temp_file_name, filename))
        {
            *err = "ld failed!";
            goto finish_up;
        }
        temp_file = fopen(temp_file_name,"r");
        nread = fread(&header, sizeof(header), 1, temp_file);
    }

    fseek(temp_file, N_TXTOFF(header), 0);
    nread = fread(load_address, true_image_size,1,temp_file);

    retval = load_symbols(filename, &ld_header, load_address);

    fclose(temp_file);
    unlink(temp_file_name);
    *address = load_address;
    *size = image_size;

    temp_file = NULL;
    load_address = NULL;

finish_up:
    if (temp_file != NULL) fclose(temp_file);
    if (load_address != NULL) free(load_address);
    return retval;
}

DynamicFunctionList *
load_symbols(filename, hdr, entry_addr)

char *filename;
struct exec *hdr;
int entry_addr;

{
    int fd;
    char *strings, *symb_table, *p, *q;
    int symtab_offset, string_offset, string_size, nsyms, i;
    struct nlist *table_entry;
    int entering = 1;
    DynamicFunctionList *head, *scanner;

    symtab_offset = N_SYMOFF(*hdr);
    string_offset = N_STROFF(*hdr);

    fd = open(filename, O_RDONLY);

    lseek(fd, string_offset, 0);
    read(fd, &string_size, sizeof(string_size));
    strings = (char *) malloc(string_size - 4);
    read(fd, strings, string_size - 4);
    nsyms = hdr->a_syms / sizeof(struct nlist);
    lseek(fd, symtab_offset, 0);
    symb_table = (char *) malloc(hdr->a_syms);
    read(fd, symb_table, hdr->a_syms);

    p = symb_table;
    for (i = 0; i < nsyms; i++)
    {
        table_entry = (struct nlist *) p;
        p += sizeof(struct nlist);
        if (! ((table_entry->n_type & N_EXT) == 0
            || (table_entry->n_type & N_TYPE) != N_TEXT))
        {
            if (entering)
            {
                head = (DynamicFunctionList *)
                       malloc(sizeof(DynamicFunctionList));
                scanner = head;
                entering = 0;
            }
            else
            {
                scanner->next = (DynamicFunctionList *)
                                malloc(sizeof(DynamicFunctionList));
                scanner = scanner->next;
            }
            /*
             * Add one for "_", ie
             * overpaid() will be _overpaid
             */

            q = strings + (table_entry->n_un.n_strx - 4) + 1;

            strcpy(scanner->funcname, q);
            scanner->func = (func_ptr) (table_entry->n_value + entry_addr);
            scanner->next = NULL;
        }
    }

    free(symb_table);
    free(strings);
    close(fd);
    return(head);
}

func_ptr
dynamic_load(err)

char **err;

{
    *err = "Dynamic load: Should not be here!";
    return(NULL);
}

/*
 *   ld -N -x -A SYMBOL_TABLE -T ADDR -o TEMPFILE FUNC -lc
 */

execld(address, tmp_file, filename)

char *address, *tmp_file, *filename;

{
    char command[256];
    int retval;

    sprintf(command,"ld -N -x -A %s -T %lx -o %s  %s -lc -lm -ll",
            pg_pathname,
            address,
            tmp_file,  filename);
    retval = OurSystem(command);
    return(retval);
}