/* vi: set sw=4 ts=4: */
/*
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */

//applet:IF_BOOTCHARTD(APPLET(bootchartd, _BB_DIR_SBIN, _BB_SUID_DROP))

//kbuild:lib-$(CONFIG_BOOTCHARTD) += bootchartd.o

//config:config BOOTCHARTD
//config:       bool "bootchartd"
//config:       default y
//config:       help
//config:         bootchartd is commonly used to profile the boot process
//config:         for the purpose of speeding it up. In this case, it is started
//config:         by the kernel as the init process. This is configured by adding
//config:         the init=/sbin/bootchartd option to the kernel command line.
//config:
//config:         It can also be used to monitor the resource usage of a specific
//config:         application or the running system in general. In this case,
//config:         bootchartd is started interactively by running bootchartd start
//config:         and stopped using bootchartd stop.
//config:
//config:config FEATURE_BOOTCHARTD_BLOATED_HEADER
//config:       bool "Compatible, bloated header"
//config:       default y
//config:       depends on BOOTCHARTD
//config:       help
//config:         Create extended header file compatible with "big" bootchartd.
//config:         "Big" bootchartd is a shell script and it dumps some
//config:         "convenient" info int the header, such as:
//config:           title = Boot chart for `hostname` (`date`)
//config:           system.uname = `uname -srvm`
//config:           system.release = `cat /etc/DISTRO-release`
//config:           system.cpu = `grep '^model name' /proc/cpuinfo | head -1` ($cpucount)
//config:           system.kernel.options = `cat /proc/cmdline`
//config:         This data is not mandatory for bootchart graph generation,
//config:         and is considered bloat. Nevertheless, this option
//config:         makes bootchartd applet to dump a subset of it.
//config:
//config:config FEATURE_BOOTCHARTD_CONFIG_FILE
//config:       bool "Support bootchartd.conf"
//config:       default y
//config:       depends on BOOTCHARTD
//config:       help
//config:         Enable reading and parsing of $PWD/bootchartd.conf
//config:         and /etc/bootchartd.conf files.

#include "libbb.h"
/* After libbb.h, since it needs sys/types.h on some systems */
#include <sys/utsname.h>

#ifdef __linux__
# include <sys/mount.h>
# ifndef MS_SILENT
#  define MS_SILENT      (1 << 15)
# endif
# ifndef MNT_DETACH
#  define MNT_DETACH 0x00000002
# endif
#endif

#define BC_VERSION_STR "0.8"

/* For debugging, set to 0:
 * strace won't work with DO_SIGNAL_SYNC set to 1.
 */
#define DO_SIGNAL_SYNC 1


//$PWD/bootchartd.conf and /etc/bootchartd.conf:
//supported options:
//# Sampling period (in seconds)
//SAMPLE_PERIOD=0.2
//
//not yet supported:
//# tmpfs size
//# (32 MB should suffice for ~20 minutes worth of log data, but YMMV)
//TMPFS_SIZE=32m
//
//# Whether to enable and store BSD process accounting information.  The
//# kernel needs to be configured to enable v3 accounting
//# (CONFIG_BSD_PROCESS_ACCT_V3). accton from the GNU accounting utilities
//# is also required.
//PROCESS_ACCOUNTING="no"
//
//# Tarball for the various boot log files
//BOOTLOG_DEST=/var/log/bootchart.tgz
//
//# Whether to automatically stop logging as the boot process completes.
//# The logger will look for known processes that indicate bootup completion
//# at a specific runlevel (e.g. gdm-binary, mingetty, etc.).
//AUTO_STOP_LOGGER="yes"
//
//# Whether to automatically generate the boot chart once the boot logger
//# completes.  The boot chart will be generated in $AUTO_RENDER_DIR.
//# Note that the bootchart package must be installed.
//AUTO_RENDER="no"
//
//# Image format to use for the auto-generated boot chart
//# (choose between png, svg and eps).
//AUTO_RENDER_FORMAT="png"
//
//# Output directory for auto-generated boot charts
//AUTO_RENDER_DIR="/var/log"


/* Globals */
struct globals {
        char jiffy_line[COMMON_BUFSIZE];
} FIX_ALIASING;
#define G (*(struct globals*)&bb_common_bufsiz1)
#define INIT_G() do { } while (0)

static void dump_file(FILE *fp, const char *filename)
{
        int fd = open(filename, O_RDONLY);
        if (fd >= 0) {
                fputs(G.jiffy_line, fp);
                fflush(fp);
                bb_copyfd_eof(fd, fileno(fp));
                close(fd);
                fputc('\n', fp);
        }
}

static int dump_procs(FILE *fp, int look_for_login_process)
{
        struct dirent *entry;
        DIR *dir = opendir("/proc");
        int found_login_process = 0;

        fputs(G.jiffy_line, fp);
        while ((entry = readdir(dir)) != NULL) {
                char name[sizeof("/proc/%u/cmdline") + sizeof(int)*3];
                int stat_fd;
                unsigned pid = bb_strtou(entry->d_name, NULL, 10);
                if (errno)
                        continue;

                /* Android's version reads /proc/PID/cmdline and extracts
                 * non-truncated process name. Do we want to do that? */

                sprintf(name, "/proc/%u/stat", pid);
                stat_fd = open(name, O_RDONLY);
                if (stat_fd >= 0) {
                        char *p;
                        char stat_line[4*1024];
                        int rd = safe_read(stat_fd, stat_line, sizeof(stat_line)-2);

                        close(stat_fd);
                        if (rd < 0)
                                continue;
                        stat_line[rd] = '\0';
                        p = strchrnul(stat_line, '\n');
                        *p++ = '\n';
                        *p = '\0';
                        fputs(stat_line, fp);
                        if (!look_for_login_process)
                                continue;
                        p = strchr(stat_line, '(');
                        if (!p)
                                continue;
                        p++;
                        strchrnul(p, ')')[0] = '\0';
                        /* Is it gdm, kdm or a getty? */
                        if (((p[0] == 'g' || p[0] == 'k' || p[0] == 'x') && p[1] == 'd' && p[2] == 'm')
                         || strstr(p, "getty")
                        ) {
                                found_login_process = 1;
                        }
                }
        }
        closedir(dir);
        fputc('\n', fp);
        return found_login_process;
}

static char *make_tempdir(void)
{
        char template[] = "/tmp/bootchart.XXXXXX";
        char *tempdir = xstrdup(mkdtemp(template));
        if (!tempdir) {
#ifdef __linux__
                /* /tmp is not writable (happens when we are used as init).
                 * Try to mount a tmpfs, them cd and lazily unmount it.
                 * Since we unmount it at once, we can mount it anywhere.
                 * Try a few locations which are likely ti exist.
                 */
                static const char dirs[] = "/mnt\0""/tmp\0""/boot\0""/proc\0";
                const char *try_dir = dirs;
                while (mount("none", try_dir, "tmpfs", MS_SILENT, "size=16m") != 0) {
                        try_dir += strlen(try_dir) + 1;
                        if (!try_dir[0])
                                bb_perror_msg_and_die("can't %smount tmpfs", "");
                }
                //bb_error_msg("mounted tmpfs on %s", try_dir);
                xchdir(try_dir);
                if (umount2(try_dir, MNT_DETACH) != 0) {
                        bb_perror_msg_and_die("can't %smount tmpfs", "un");
                }
#else
                bb_perror_msg_and_die("can't create temporary directory");
#endif
        } else {
                xchdir(tempdir);
        }
        return tempdir;
}

static void do_logging(unsigned sample_period_us)
{
        //# Enable process accounting if configured
        //if [ "$PROCESS_ACCOUNTING" = "yes" ]; then
        //      [ -e kernel_pacct ] || : > kernel_pacct
        //      accton kernel_pacct
        //fi

        FILE *proc_stat = xfopen("proc_stat.log", "w");
        FILE *proc_diskstats = xfopen("proc_diskstats.log", "w");
        //FILE *proc_netdev = xfopen("proc_netdev.log", "w");
        FILE *proc_ps = xfopen("proc_ps.log", "w");
        int look_for_login_process = (getppid() == 1);
        unsigned count = 60*1000*1000 / sample_period_us; /* ~1 minute */

        while (--count && !bb_got_signal) {
                char *p;
                int len = open_read_close("/proc/uptime", G.jiffy_line, sizeof(G.jiffy_line)-2);
                if (len < 0)
                        goto wait_more;
                /* /proc/uptime has format "NNNNNN.MM NNNNNNN.MM" */
                /* we convert it to "NNNNNNMM\n" (using first value) */
                G.jiffy_line[len] = '\0';
                p = strchr(G.jiffy_line, '.');
                if (!p)
                        goto wait_more;
                while (isdigit(*++p))
                        p[-1] = *p;
                p[-1] = '\n';
                p[0] = '\0';

                dump_file(proc_stat, "/proc/stat");
                dump_file(proc_diskstats, "/proc/diskstats");
                //dump_file(proc_netdev, "/proc/net/dev");
                if (dump_procs(proc_ps, look_for_login_process)) {
                        /* dump_procs saw a getty or {g,k,x}dm
                         * stop logging in 2 seconds:
                         */
                        if (count > 2*1000*1000 / sample_period_us)
                                count = 2*1000*1000 / sample_period_us;
                }
                fflush_all();
 wait_more:
                usleep(sample_period_us);
        }

        // [ -e kernel_pacct ] && accton off
}

static void finalize(char *tempdir, const char *prog)
{
        //# Stop process accounting if configured
        //local pacct=
        //[ -e kernel_pacct ] && pacct=kernel_pacct

        FILE *header_fp = xfopen("header", "w");

        if (prog)
                fprintf(header_fp, "profile.process = %s\n", prog);

        fputs("version = "BC_VERSION_STR"\n", header_fp);
        if (ENABLE_FEATURE_BOOTCHARTD_BLOATED_HEADER) {
                char *hostname;
                char *kcmdline;
                time_t t;
                struct tm tm_time;
                /* x2 for possible localized weekday/month names */
                char date_buf[sizeof("Mon Jun 21 05:29:03 CEST 2010") * 2];
                struct utsname unamebuf;

                hostname = safe_gethostname();
                time(&t);
                localtime_r(&t, &tm_time);
                strftime(date_buf, sizeof(date_buf), "%a %b %e %H:%M:%S %Z %Y", &tm_time);
                fprintf(header_fp, "title = Boot chart for %s (%s)\n", hostname, date_buf);
                if (ENABLE_FEATURE_CLEAN_UP)
                        free(hostname);

                uname(&unamebuf); /* never fails */
                /* same as uname -srvm */
                fprintf(header_fp, "system.uname = %s %s %s %s\n",
                                unamebuf.sysname,
                                unamebuf.release,
                                unamebuf.version,
                                unamebuf.machine
                );

                //system.release = `cat /etc/DISTRO-release`
                //system.cpu = `grep '^model name' /proc/cpuinfo | head -1` ($cpucount)

                kcmdline = xmalloc_open_read_close("/proc/cmdline", NULL);
                /* kcmdline includes trailing "\n" */
                fprintf(header_fp, "system.kernel.options = %s", kcmdline);
                if (ENABLE_FEATURE_CLEAN_UP)
                        free(kcmdline);
        }
        fclose(header_fp);

        /* Package log files */
        system("tar -zcf /var/log/bootchart.tgz header *.log"); // + $pacct
        /* Clean up (if we are not in detached tmpfs) */
        if (tempdir) {
                unlink("header");
                unlink("proc_stat.log");
                unlink("proc_diskstats.log");
                //unlink("proc_netdev.log");
                unlink("proc_ps.log");
                rmdir(tempdir);
        }

        /* shell-based bootchartd tries to run /usr/bin/bootchart if $AUTO_RENDER=yes:
         * /usr/bin/bootchart -o "$AUTO_RENDER_DIR" -f $AUTO_RENDER_FORMAT "$BOOTLOG_DEST"
         */
}

//usage:#define bootchartd_trivial_usage
//usage:       "start [PROG ARGS]|stop|init"
//usage:#define bootchartd_full_usage "\n\n"
//usage:       "Create /var/log/bootchart.tgz with boot chart data\n"
//usage:     "\nOptions:"
//usage:     "\nstart: start background logging; with PROG, run PROG, then kill logging with USR1"
//usage:     "\nstop: send USR1 to all bootchartd processes"
//usage:     "\ninit: start background logging; stop when getty/xdm is seen (for init scripts)"
//usage:     "\nUnder PID 1: as init, then exec $bootchart_init, /init, /sbin/init"

int bootchartd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int bootchartd_main(int argc UNUSED_PARAM, char **argv)
{
        unsigned sample_period_us;
        pid_t parent_pid, logger_pid;
        smallint cmd;
        enum {
                CMD_STOP = 0,
                CMD_START,
                CMD_INIT,
                CMD_PID1, /* used to mark pid 1 case */
        };

        INIT_G();

        parent_pid = getpid();
        if (argv[1]) {
                cmd = index_in_strings("stop\0""start\0""init\0", argv[1]);
                if (cmd < 0)
                        bb_show_usage();
                if (cmd == CMD_STOP) {
                        pid_t *pidList = find_pid_by_name("bootchartd");
                        while (*pidList != 0) {
                                if (*pidList != parent_pid)
                                        kill(*pidList, SIGUSR1);
                                pidList++;
                        }
                        return EXIT_SUCCESS;
                }
        } else {
                if (parent_pid != 1)
                        bb_show_usage();
                cmd = CMD_PID1;
        }

        /* Here we are in START, INIT or CMD_PID1 state */

        /* Read config file: */
        sample_period_us = 200 * 1000;
        if (ENABLE_FEATURE_BOOTCHARTD_CONFIG_FILE) {
                char* token[2];
                parser_t *parser = config_open2("/etc/bootchartd.conf" + 5, fopen_for_read);
                if (!parser)
                        parser = config_open2("/etc/bootchartd.conf", fopen_for_read);
                while (config_read(parser, token, 2, 0, "#=", PARSE_NORMAL & ~PARSE_COLLAPSE)) {
                        if (strcmp(token[0], "SAMPLE_PERIOD") == 0 && token[1])
                                sample_period_us = atof(token[1]) * 1000000;
                }
                config_close(parser);
        }
        if ((int)sample_period_us <= 0)
                sample_period_us = 1; /* prevent division by 0 */

        /* Create logger child: */
        logger_pid = fork_or_rexec(argv);

        if (logger_pid == 0) { /* child */
                char *tempdir;

                bb_signals(0
                        + (1 << SIGUSR1)
                        + (1 << SIGUSR2)
                        + (1 << SIGTERM)
                        + (1 << SIGQUIT)
                        + (1 << SIGINT)
                        + (1 << SIGHUP)
                        , record_signo);

                if (DO_SIGNAL_SYNC)
                        /* Inform parent that we are ready */
                        raise(SIGSTOP);

                /* If we are started by kernel, PATH might be unset.
                 * In order to find "tar", let's set some sane PATH:
                 */
                if (cmd == CMD_PID1 && !getenv("PATH"))
                        putenv((char*)bb_PATH_root_path);

                tempdir = make_tempdir();
                do_logging(sample_period_us);
                finalize(tempdir, cmd == CMD_START ? argv[2] : NULL);
                return EXIT_SUCCESS;
        }

        /* parent */

        if (DO_SIGNAL_SYNC) {
                /* Wait for logger child to set handlers, then unpause it.
                 * Otherwise with short-lived PROG (e.g. "bootchartd start true")
                 * we might send SIGUSR1 before logger sets its handler.
                 */
                waitpid(logger_pid, NULL, WUNTRACED);
                kill(logger_pid, SIGCONT);
        }

        if (cmd == CMD_PID1) {
                char *bootchart_init = getenv("bootchart_init");
                if (bootchart_init)
                        execl(bootchart_init, bootchart_init, NULL);
                execl("/init", "init", NULL);
                execl("/sbin/init", "init", NULL);
                bb_perror_msg_and_die("can't execute '%s'", "/sbin/init");
        }

        if (cmd == CMD_START && argv[2]) { /* "start PROG ARGS" */
                pid_t pid = xvfork();
                if (pid == 0) { /* child */
                        argv += 2;
                        execvp(argv[0], argv);
                        bb_perror_msg_and_die("can't execute '%s'", argv[0]);
                }
                /* parent */
                waitpid(pid, NULL, 0);
                kill(logger_pid, SIGUSR1);
        }

        return EXIT_SUCCESS;
}