usr/src/usr.bin/nm/nm.c

/*
 * Copyright (c) 1989 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Hans Huebner.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1989 The Regents of the University of California.\n\
 All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)nm.c        5.8 (Berkeley) 5/2/91";
#endif /* not lint */

#include <sys/types.h>
#include <a.out.h>
#include <stab.h>
#include <ar.h>
#include <ranlib.h>
#include <unistd.h>
#include <errno.h>
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int ignore_bad_archive_entries = 1;
int print_only_external_symbols;
int print_only_undefined_symbols;
int print_all_symbols;
int print_file_each_line;
int fcount;

int rev;
int fname(), rname(), value();
int (*sfunc)() = fname;

/* some macros for symbol type (nlist.n_type) handling */
#define IS_DEBUGGER_SYMBOL(x)   ((x) & N_STAB)
#define IS_EXTERNAL(x)          ((x) & N_EXT)
#define SYMBOL_TYPE(x)          ((x) & (N_TYPE | N_STAB))

void *emalloc();

/*
 * main()
 *      parse command line, execute process_file() for each file
 *      specified on the command line.
 */
main(argc, argv)
        int argc;
        char **argv;
{
        extern int optind;
        int ch, errors;

        while ((ch = getopt(argc, argv, "agnopruw")) != EOF) {
                switch (ch) {
                case 'a':
                        print_all_symbols = 1;
                        break;
                case 'g':
                        print_only_external_symbols = 1;
                        break;
                case 'n':
                        sfunc = value;
                        break;
                case 'o':
                        print_file_each_line = 1;
                        break;
                case 'p':
                        sfunc = NULL;
                        break;
                case 'r':
                        rev = 1;
                        break;
                case 'u':
                        print_only_undefined_symbols = 1;
                        break;
                case 'w':
                        ignore_bad_archive_entries = 0;
                        break;
                case '?':
                default:
                        usage();
                }
        }
        fcount = argc - optind;
        argv += optind;

        if (rev && sfunc == fname)
                sfunc = rname;

        if (!fcount)
                errors = process_file("a.out");
        else {
                errors = 0;
                do {
                        errors |= process_file(*argv);
                } while (*++argv);
        }
        exit(errors);
}

/*
 * process_file()
 *      show symbols in the file given as an argument.  Accepts archive and
 *      object files as input.
 */
process_file(fname)
        char *fname;
{
        struct exec exec_head;
        FILE *fp;
        int retval;
        char magic[SARMAG];

        if (!(fp = fopen(fname, "r"))) {
                (void)fprintf(stderr, "nm: cannot read %s.\n", fname);
                return(1);
        }

        if (fcount > 1)
                (void)printf("\n%s:\n", fname);

        /*
         * first check whether this is an object file - read a object
         * header, and skip back to the beginning
         */
        if (fread((char *)&exec_head, sizeof(exec_head), (size_t)1, fp) != 1) {
                (void)fprintf(stderr, "nm: %s: bad format.\n", fname);
                (void)fclose(fp);
                return(1);
        }
        rewind(fp);

        /* this could be an archive */
        if (N_BADMAG(exec_head)) {
                if (fread(magic, sizeof(magic), (size_t)1, fp) != 1 ||
                    strncmp(magic, ARMAG, SARMAG)) {
                        (void)fprintf(stderr,
                            "nm: %s: not object file or archive.\n", fname);
                        (void)fclose(fp);
                        return(1);
                }
                retval = show_archive(fname, fp);
        } else
                retval = show_objfile(fname, fp);
        (void)fclose(fp);
        return(retval);
}

/*
 * show_archive()
 *      show symbols in the given archive file
 */
show_archive(fname, fp)
        char *fname;
        FILE *fp;
{
        struct ar_hdr ar_head;
        struct exec exec_head;
        int i, rval;
        long last_ar_off;
        char *p, *name;

        name = emalloc(sizeof(ar_head.ar_name) + strlen(fname) + 3);

        rval = 0;

        /* while there are more entries in the archive */
        while (fread((char *)&ar_head, sizeof(ar_head), (size_t)1, fp) == 1) {
                /* bad archive entry - stop processing this archive */
                if (strncmp(ar_head.ar_fmag, ARFMAG, sizeof(ar_head.ar_fmag))) {
                        (void)fprintf(stderr,
                            "nm: %s: bad format archive header", fname);
                        (void)free(name);
                        return(1);
                }

                /* remember start position of current archive object */
                last_ar_off = ftell(fp);

                /* skip ranlib entries */
                if (!strncmp(ar_head.ar_name, RANLIBMAG, sizeof(RANLIBMAG) - 1))
                        goto skip;

                /*
                 * construct a name of the form "archive.a:obj.o:" for the
                 * current archive entry if the object name is to be printed
                 * on each output line
                 */
                p = name;
                if (print_file_each_line)
                        p += sprintf(p, "%s:", fname);
                for (i = 0; i < sizeof(ar_head.ar_name); ++i)
                        if (ar_head.ar_name[i] && ar_head.ar_name[i] != ' ')
                                *p++ = ar_head.ar_name[i];
                *p++ = '\0';

                /* get and check current object's header */
                if (fread((char *)&exec_head, sizeof(exec_head),
                    (size_t)1, fp) != 1) {
                        (void)fprintf(stderr, "nm: %s: premature EOF.\n", name);
                        (void)free(name);
                        return(1);
                }

                if (N_BADMAG(exec_head)) {
                        if (!ignore_bad_archive_entries) {
                                (void)fprintf(stderr,
                                    "nm: %s: bad format.\n", name);
                                rval = 1;
                        }
                } else {
                        (void)fseek(fp, (long)-sizeof(exec_head),
                            SEEK_CUR);
                        if (!print_file_each_line)
                                (void)printf("\n%s:\n", name);
                        rval |= show_objfile(name, fp);
                }

                /*
                 * skip to next archive object - it starts at the next
                 * even byte boundary
                 */
#define even(x) (((x) + 1) & ~1)
skip:           if (fseek(fp, last_ar_off + even(atol(ar_head.ar_size)),
                    SEEK_SET)) {
                        (void)fprintf(stderr,
                            "nm: %s: %s\n", fname, strerror(errno));
                        (void)free(name);
                        return(1);
                }
        }
        (void)free(name);
        return(rval);
}

/*
 * show_objfile()
 *      show symbols from the object file pointed to by fp.  The current
 *      file pointer for fp is expected to be at the beginning of an a.out
 *      header.
 */
show_objfile(objname, fp)
        char *objname;
        FILE *fp;
{
        register struct nlist *names, *np;
        register int i, nnames, nrawnames;
        struct exec head;
        long stabsize;
        char *stab;

        /* read a.out header */
        if (fread((char *)&head, sizeof(head), (size_t)1, fp) != 1) {
                (void)fprintf(stderr,
                    "nm: %s: cannot read header.\n", objname);
                return(1);
        }

        /*
         * skip back to the header - the N_-macros return values relative
         * to the beginning of the a.out header
         */
        if (fseek(fp, (long)-sizeof(head), SEEK_CUR)) {
                (void)fprintf(stderr,
                    "nm: %s: %s\n", objname, strerror(errno));
                return(1);
        }

        /* stop if this is no valid object file */
        if (N_BADMAG(head)) {
                (void)fprintf(stderr,
                    "nm: %s: bad format.\n", objname);
                return(1);
        }

        /* stop if the object file contains no symbol table */
        if (!head.a_syms) {
                (void)fprintf(stderr,
                    "nm: %s: no name list.\n", objname);
                return(1);
        }

        if (fseek(fp, (long)N_SYMOFF(head), SEEK_CUR)) {
                (void)fprintf(stderr,
                    "nm: %s: %s\n", objname, strerror(errno));
                return(1);
        }

        /* get memory for the symbol table */
        names = emalloc((size_t)head.a_syms);
        nrawnames = head.a_syms / sizeof(*names);
        if (fread((char *)names, (size_t)head.a_syms, (size_t)1, fp) != 1) {
                (void)fprintf(stderr,
                    "nm: %s: cannot read symbol table.\n", objname);
                (void)free((char *)names);
                return(1);
        }

        /*
         * Following the symbol table comes the string table.  The first
         * 4-byte-integer gives the total size of the string table
         * _including_ the size specification itself.
         */
        if (fread((char *)&stabsize, sizeof(stabsize), (size_t)1, fp) != 1) {
                (void)fprintf(stderr,
                    "nm: %s: cannot read stab size.\n", objname);
                (void)free((char *)names);
                return(1);
        }
        stab = emalloc((size_t)stabsize);

        /*
         * read the string table offset by 4 - all indices into the string
         * table include the size specification.
         */
        stabsize -= 4;          /* we already have the size */
        if (fread(stab + 4, (size_t)stabsize, (size_t)1, fp) != 1) {
                (void)fprintf(stderr,
                    "nm: %s: stab truncated..\n", objname);
                (void)free((char *)names);
                (void)free(stab);
                return(1);
        }

        /*
         * fix up the symbol table and filter out unwanted entries
         *
         * common symbols are characterized by a n_type of N_UNDF and a
         * non-zero n_value -- change n_type to N_COMM for all such
         * symbols to make life easier later.
         *
         * filter out all entries which we don't want to print anyway
         */
        for (np = names, i = nnames = 0; i < nrawnames; np++, i++) {
                if (SYMBOL_TYPE(np->n_type) == N_UNDF && np->n_value)
                        np->n_type = N_COMM | (np->n_type & N_EXT);
                if (!print_all_symbols && IS_DEBUGGER_SYMBOL(np->n_type))
                        continue;
                if (print_only_external_symbols && !IS_EXTERNAL(np->n_type))
                        continue;
                if (print_only_undefined_symbols &&
                    SYMBOL_TYPE(np->n_type) != N_UNDF)
                        continue;

                /*
                 * make n_un.n_name a character pointer by adding the string
                 * table's base to n_un.n_strx
                 *
                 * don't mess with zero offsets
                 */
                if (np->n_un.n_strx)
                        np->n_un.n_name = stab + np->n_un.n_strx;
                else
                        np->n_un.n_name = "";
                names[nnames++] = *np;
        }

        /* sort the symbol table if applicable */
        if (sfunc)
                qsort((char *)names, (size_t)nnames, sizeof(*names), sfunc);

        /* print out symbols */
        for (np = names, i = 0; i < nnames; np++, i++)
                print_symbol(objname, np);

        (void)free((char *)names);
        (void)free(stab);
        return(0);
}

/*
 * print_symbol()
 *      show one symbol
 */
print_symbol(objname, sym)
        char *objname;
        register struct nlist *sym;
{
        char *typestring(), typeletter();

        if (print_file_each_line)
                (void)printf("%s:", objname);

        /*
         * handle undefined-only format seperately (no space is
         * left for symbol values, no type field is printed)
         */
        if (print_only_undefined_symbols) {
                (void)puts(sym->n_un.n_name);
                return;
        }

        /* print symbol's value */
        if (SYMBOL_TYPE(sym->n_type) == N_UNDF)
                (void)printf("        ");
        else
                (void)printf("%08lx", sym->n_value);

        /* print type information */
        if (IS_DEBUGGER_SYMBOL(sym->n_type))
                (void)printf(" - %02x %04x %5s ", sym->n_other,
                    sym->n_desc&0xffff, typestring(sym->n_type));
        else
                (void)printf(" %c ", typeletter(sym->n_type));

        /* print the symbol's name */
        (void)puts(sym->n_un.n_name);
}

/*
 * typestring()
 *      return the a description string for an STAB entry
 */
char *
typestring(type)
        register u_char type;
{
        switch(type) {
        case N_BCOMM:
                return("BCOMM");
        case N_ECOML:
                return("ECOML");
        case N_ECOMM:
                return("ECOMM");
        case N_ENTRY:
                return("ENTRY");
        case N_FNAME:
                return("FNAME");
        case N_FUN:
                return("FUN");
        case N_GSYM:
                return("GSYM");
        case N_LBRAC:
                return("LBRAC");
        case N_LCSYM:
                return("LCSYM");
        case N_LENG:
                return("LENG");
        case N_LSYM:
                return("LSYM");
        case N_PC:
                return("PC");
        case N_PSYM:
                return("PSYM");
        case N_RBRAC:
                return("RBRAC");
        case N_RSYM:
                return("RSYM");
        case N_SLINE:
                return("SLINE");
        case N_SO:
                return("SO");
        case N_SOL:
                return("SOL");
        case N_SSYM:
                return("SSYM");
        case N_STSYM:
                return("STSYM");
        }
        return("???");
}

/*
 * typeletter()
 *      return a description letter for the given basic type code of an
 *      symbol table entry.  The return value will be upper case for
 *      external, lower case for internal symbols.
 */
char
typeletter(type)
        u_char type;
{
        switch(SYMBOL_TYPE(type)) {
        case N_ABS:
                return(IS_EXTERNAL(type) ? 'A' : 'a');
        case N_BSS:
                return(IS_EXTERNAL(type) ? 'B' : 'b');
        case N_COMM:
                return(IS_EXTERNAL(type) ? 'C' : 'c');
        case N_DATA:
                return(IS_EXTERNAL(type) ? 'D' : 'd');
        case N_FN:
                return(IS_EXTERNAL(type) ? 'F' : 'f');
        case N_TEXT:
                return(IS_EXTERNAL(type) ? 'T' : 't');
        case N_UNDF:
                return(IS_EXTERNAL(type) ? 'U' : 'u');
        }
        return('?');
}

fname(a0, b0)
        void *a0, *b0;
{
        struct nlist *a = a0, *b = b0;

        return(strcmp(a->n_un.n_name, b->n_un.n_name));
}

rname(a0, b0)
        void *a0, *b0;
{
        struct nlist *a = a0, *b = b0;

        return(strcmp(b->n_un.n_name, a->n_un.n_name));
}

value(a0, b0)
        void *a0, *b0;
{
        register struct nlist *a = a0, *b = b0;

        if (SYMBOL_TYPE(a->n_type) == N_UNDF)
                if (SYMBOL_TYPE(b->n_type) == N_UNDF)
                        return(0);
                else
                        return(-1);
        else if (SYMBOL_TYPE(b->n_type) == N_UNDF)
                return(1);
        if (rev) {
                if (a->n_value == b->n_value)
                        return(rname(a0, b0));
                return(b->n_value > a->n_value ? 1 : -1);
        } else {
                if (a->n_value == b->n_value)
                        return(fname(a0, b0));
                return(a->n_value > b->n_value ? 1 : -1);
        }
}

void *
emalloc(size)
        size_t size;
{
        char *p;

        /* NOSTRICT */
        if (p = malloc(size))
                return(p);
        (void)fprintf(stderr, "nm: %s\n", strerror(errno));
        exit(1);
}

usage()
{
        (void)fprintf(stderr, "usage: nm [-agnopruw] [file ...]\n");
        exit(1);
}