/* vi: set sw=4 ts=4: */
/*
 * readprofile.c - used to read /proc/profile
 *
 * Copyright (C) 1994,1996 Alessandro Rubini (rubini@ipvvis.unipv.it)
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */

/*
 * 1999-02-22 Arkadiusz Mickiewicz <misiek@pld.ORG.PL>
 * - added Native Language Support
 * 1999-09-01 Stephane Eranian <eranian@cello.hpl.hp.com>
 * - 64bit clean patch
 * 3Feb2001 Andrew Morton <andrewm@uow.edu.au>
 * - -M option to write profile multiplier.
 * 2001-11-07 Werner Almesberger <wa@almesberger.net>
 * - byte order auto-detection and -n option
 * 2001-11-09 Werner Almesberger <wa@almesberger.net>
 * - skip step size (index 0)
 * 2002-03-09 John Levon <moz@compsoc.man.ac.uk>
 * - make maplineno do something
 * 2002-11-28 Mads Martin Joergensen +
 * - also try /boot/System.map-`uname -r`
 * 2003-04-09 Werner Almesberger <wa@almesberger.net>
 * - fixed off-by eight error and improved heuristics in byte order detection
 * 2003-08-12 Nikita Danilov <Nikita@Namesys.COM>
 * - added -s option; example of use:
 * "readprofile -s -m /boot/System.map-test | grep __d_lookup | sort -n -k3"
 *
 * Taken from util-linux and adapted for busybox by
 * Paul Mundt <lethal@linux-sh.org>.
 */
//config:config READPROFILE
//config:       bool "readprofile (7.1 kb)"
//config:       default y
//config:       help
//config:       This allows you to parse /proc/profile for basic profiling.

//applet:IF_READPROFILE(APPLET(readprofile, BB_DIR_USR_SBIN, BB_SUID_DROP))

//kbuild:lib-$(CONFIG_READPROFILE) += readprofile.o

//usage:#define readprofile_trivial_usage
//usage:       "[OPTIONS]"
//usage:#define readprofile_full_usage "\n\n"
//usage:       "        -m MAPFILE      (Default: /boot/System.map)"
//usage:     "\n        -p PROFILE      (Default: /proc/profile)"
//usage:     "\n        -M NUM          Set the profiling multiplier to NUM"
//usage:     "\n        -i              Print only info about the sampling step"
//usage:     "\n        -v              Verbose"
//usage:     "\n        -a              Print all symbols, even if count is 0"
//usage:     "\n        -b              Print individual histogram-bin counts"
//usage:     "\n        -s              Print individual counters within functions"
//usage:     "\n        -r              Reset all the counters (root only)"
//usage:     "\n        -n              Disable byte order auto-detection"

#include "libbb.h"
#include <sys/utsname.h>

#define S_LEN 128

int readprofile_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int readprofile_main(int argc UNUSED_PARAM, char **argv)
{
        FILE *map;
        const char *mapFile, *proFile;
        unsigned long indx;
        size_t len;
        uint64_t add0;
        unsigned int step;
        unsigned int *buf, total, fn_len;
        unsigned long long fn_add, next_add;     /* current and next address */
        char fn_name[S_LEN], next_name[S_LEN];   /* current and next name */
        char mapline[S_LEN];
        char mode[8];
        int maplineno;
        int multiplier;
        unsigned opt;
        enum {
                OPT_M = (1 << 0),
                OPT_m = (1 << 1),
                OPT_p = (1 << 2),
                OPT_n = (1 << 3),
                OPT_a = (1 << 4),
                OPT_b = (1 << 5),
                OPT_s = (1 << 6),
                OPT_i = (1 << 7),
                OPT_r = (1 << 8),
                OPT_v = (1 << 9),
        };
#define optMult    (opt & OPT_M)
#define optNative  (opt & OPT_n)
#define optAll     (opt & OPT_a)
#define optBins    (opt & OPT_b)
#define optSub     (opt & OPT_s)
#define optInfo    (opt & OPT_i)
#define optReset   (opt & OPT_r)
#define optVerbose (opt & OPT_v)

#define next (current^1)

        proFile = "/proc/profile";
        mapFile = "/boot/System.map";
        multiplier = 0;

        opt = getopt32(argv, "M:+m:p:nabsirv", &multiplier, &mapFile, &proFile);

        if (opt & (OPT_M|OPT_r)) { /* mult or reset, or both */
                int fd, to_write;

                /*
                 * When writing the multiplier, if the length of the write is
                 * not sizeof(int), the multiplier is not changed
                 */
                to_write = sizeof(int);
                if (!optMult)
                        to_write = 1;  /* sth different from sizeof(int) */

                fd = xopen("/proc/profile", O_WRONLY);
                xwrite(fd, &multiplier, to_write);
                close(fd);
                return EXIT_SUCCESS;
        }

        /*
         * Use an fd for the profiling buffer, to skip stdio overhead
         */
        len = MAXINT(ssize_t);
        buf = xmalloc_xopen_read_close(proFile, &len);
        len /= sizeof(*buf);

        if (!optNative) {
                int big = 0, small = 0;
                unsigned *p;

                for (p = buf+1; p < buf+len; p++) {
                        if (*p & ~0U << (sizeof(*buf)*4))
                                big++;
                        if (*p & ((1 << (sizeof(*buf)*4))-1))
                                small++;
                }
                if (big > small) {
                        bb_simple_error_msg("assuming reversed byte order, "
                                "use -n to force native byte order");
                        BUILD_BUG_ON(sizeof(*p) > 8);
                        for (p = buf; p < buf+len; p++) {
                                if (sizeof(*p) == 2)
                                        *p = bswap_16(*p);
                                if (sizeof(*p) == 4)
                                        *p = bswap_32(*p);
                                if (sizeof(*p) == 8)
                                        *p = bb_bswap_64(*p);
                        }
                }
        }

        step = buf[0];
        if (optInfo) {
                printf("Sampling_step: %u\n", step);
                return EXIT_SUCCESS;
        }

        map = xfopen_for_read(mapFile);
        add0 = 0;
        maplineno = 1;
        while (fgets(mapline, S_LEN, map)) {
                if (sscanf(mapline, "%llx %s %s", &fn_add, mode, fn_name) != 3)
                        bb_error_msg_and_die("%s(%i): wrong map line",
                                        mapFile, maplineno);

                if (strcmp(fn_name, "_stext") == 0) /* only elf works like this */ {
                        add0 = fn_add;
                        break;
                }
                maplineno++;
        }

        if (!add0)
                bb_error_msg_and_die("can't find \"_stext\" in %s", mapFile);

        /*
         * Main loop.
         */
        total = 0;
        indx = 1;
        while (fgets(mapline, S_LEN, map)) {
                bool header_printed;
                unsigned int this;

                if (sscanf(mapline, "%llx %s %s", &next_add, mode, next_name) != 3)
                        bb_error_msg_and_die("%s(%i): wrong map line",
                                        mapFile, maplineno);

                header_printed = 0;

                /* ignore any LEADING (before a '[tT]' symbol is found)
                   Absolute symbols */
                if ((mode[0] == 'A' || mode[0] == '?') && total == 0)
                        continue;
                if ((mode[0]|0x20) != 't' && (mode[0]|0x20) != 'w') {
                        break;  /* only text is profiled */
                }

                if (indx >= len)
                        bb_simple_error_msg_and_die("profile address out of range. "
                                        "Wrong map file?");

                this = 0;
                while (indx < (next_add-add0)/step) {
                        if (optBins && (buf[indx] || optAll)) {
                                if (!header_printed) {
                                        printf("%s:\n", fn_name);
                                        header_printed = 1;
                                }
                                printf("\t%"PRIx64"\t%u\n", (indx - 1)*step + add0, buf[indx]);
                        }
                        this += buf[indx++];
                }
                total += this;

                if (optBins) {
                        if (optVerbose || this > 0)
                                printf("  total\t\t\t\t%u\n", this);
                } else
                if ((this || optAll)
                 && (fn_len = next_add-fn_add) != 0
                ) {
                        if (optVerbose)
                                printf("%016llx %-40s %6u %8.4f\n", fn_add,
                                        fn_name, this, this/(double)fn_len);
                        else
                                printf("%6u %-40s %8.4f\n",
                                        this, fn_name, this/(double)fn_len);
                        if (optSub) {
                                unsigned long long scan;

                                for (scan = (fn_add-add0)/step + 1;
                                     scan < (next_add-add0)/step; scan++) {
                                        unsigned long long addr;

                                        addr = (scan - 1)*step + add0;
                                        printf("\t%#llx\t%s+%#llx\t%u\n",
                                                addr, fn_name, addr - fn_add,
                                                buf[scan]);
                                }
                        }
                }

                fn_add = next_add;
                strcpy(fn_name, next_name);

                maplineno++;
        }

        /* clock ticks, out of kernel text - probably modules */
        printf("%6u *unknown*\n", buf[len-1]);

        /* trailer */
        if (optVerbose)
                printf("%016x %-40s %6u %8.4f\n",
                        0, "total", total, total/(double)(fn_add-add0));
        else
                printf("%6u %-40s %8.4f\n",
                        total, "total", total/(double)(fn_add-add0));

        if (ENABLE_FEATURE_CLEAN_UP) {
                fclose(map);
                free(buf);
        }

        return EXIT_SUCCESS;
}