Katyusha's blog

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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <sys/poll.h>
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#include <sys/time.h>
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#include <time.h>
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// Feel free to change the data structures generated by AI.
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#define MAX_SYSCALLS 1024
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#define TOP_N 5
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extern char **environ;
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typedef struct {
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    char name[64];
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    double time;
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} syscall_stat;
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typedef struct {
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    syscall_stat stats[MAX_SYSCALLS];
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    int count;
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    double total_time;
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} syscall_stats;
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int parse_strace_line(char *line, char *syscall_name, double *time) {
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    if (!('a' <= line[0] && line[0] <= 'z')) return -1;
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    int n = strlen(line);
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    int flag1 = 0, flag2 = 0, flag3 = 0;
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    int name_ptr = 0;
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    *time = 0;
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    double base = 1.0;
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    for (int i = 0; i < n; i++) {
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        if (!flag1) syscall_name[name_ptr++] = line[i];
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        if (i != n - 1 && !flag1 && line[i + 1] == '(') flag1 = 1;
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        if (line[i] == '<') flag2 = 1;
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        else if (flag2 && line[i] == '>') flag2 = 0;
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        else if (flag2) {
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            if (line[i] == '.') flag3 = 1;
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            else if (!flag3) {
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                *time = (*time) * 10 + (line[i] - '0');
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            }else {
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                base /= 10;
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                *time += base * (line[i] - '0');
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            }
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        }
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    }
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    syscall_name[name_ptr] = '\0';
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    return 0;
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}
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void add_syscall(syscall_stats *stats, const char *name, double time) {
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    (*stats).total_time += time;
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    int n = (*stats).count;
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    for (int i = 0; i < n; i++) {
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        if (strcmp((*stats).stats[i].name, name) == 0) {
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            (*stats).stats[i].time += time;
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            return;
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        }
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    }
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    int _len = strlen(name);
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    memcpy((*stats).stats[n].name, name, sizeof(char) * (_len + 1));
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    (*stats).stats[n].time = time;
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    (*stats).count++;
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}
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void swap(syscall_stat *a, syscall_stat *b) {
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    syscall_stat c = *a;
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    *a = *b;
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    *b = c;
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}
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void print_top_syscalls(syscall_stats *stats, int k) {
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    int n = (*stats).count;
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    while (1) {
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        int flag = 0;
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        for (int i = 0; i + 1 < n; i++) {
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            if ((*stats).stats[i].time < (*stats).stats[i + 1].time) {
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                swap(((*stats).stats + i), ((*stats).stats + i + 1));
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                flag = 1;
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            }
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        }
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        if (!flag) break;
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    }
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    k = k > n ? n : k;
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    for (int i = 0; i < k; i++) {
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        printf("%s (%d%%)\n", (*stats).stats[i].name, (int)((*stats).stats[i].time / (*stats).total_time * 100.0));
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    }
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    for (int i = 0; i < 80; i++) {
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        fputc('\0', stdout);
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    }
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    fflush(stdout);
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}
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char buffer[1 << 16];
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int buffer_ptr;
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syscall_stats ss;
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int handle_buffer() {
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    int pos = 0, retval = 0;
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    for (int i = 0; i < buffer_ptr; i++) {
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        if (buffer[i] == '\n') {
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            int len = i - pos + 1;
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            char *line = (char *)malloc(sizeof(char) * (len + 1));
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            memcpy(line, buffer + pos, sizeof(char) * len);
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            line[len] = '\0';
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            char *syscall_name = (char *)malloc(sizeof(char) * 64);
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            double time;
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            int ret = parse_strace_line(line, syscall_name, &time);
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            pos = i + 1;
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            if (ret == -1) {
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                retval = -1;
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                free(line); free(syscall_name);
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                continue;
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            }
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            add_syscall(&ss, syscall_name, time);
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            free(line); free(syscall_name);
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        }
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    }
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    int _buffer_ptr = buffer_ptr - pos;
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    for (int i = 0; i < _buffer_ptr; i++) {
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        buffer[i] = buffer[pos++];
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    }
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    buffer_ptr = _buffer_ptr; buffer[buffer_ptr] = '\0';
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    return retval;
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}
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int main(int argc, char *argv[]) {
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    int pipefd[2];
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    if (pipe(pipefd) == -1) {
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        perror("pipe error\n");
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        return 1;
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    }
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    int pid = fork();
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    if (pid == 0) { //child
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        close(pipefd[0]);
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        dup2(pipefd[1], STDERR_FILENO);
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        close(pipefd[1]);
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        char ** my_argv = (char**)malloc(sizeof (char*) * (argc + 2));
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        my_argv[0] = "strace";
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        my_argv[1] = "-T";
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        for (int i = 1; i < argc; i++) {
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            my_argv[i + 1] = argv[i];
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        }
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        my_argv[argc + 1] = NULL;
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        execve("/bin/strace", my_argv, environ);
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    } else { //parent
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        close(pipefd[1]);
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        dup2(pipefd[0], STDIN_FILENO);
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        close(pipefd[0]);
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        struct pollfd fds[2];
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        fds[0].fd = STDIN_FILENO; fds[0].events = POLLIN | POLLHUP;
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        int timeout = 100000;
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        while (1) {
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            struct timeval now, _now;
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            gettimeofday(&now, NULL);
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            int r = poll(fds, 1, timeout / 1000 + 5);
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            gettimeofday(&_now, NULL);
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            int dif = (_now.tv_sec - now.tv_sec) * 1000000 + (_now.tv_usec - now.tv_usec);
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            timeout -= dif;
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            if (r > 0) {
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                if (fds[0].revents & POLLIN) {
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                    int len;
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                    if ((len = read(STDIN_FILENO, buffer + buffer_ptr, sizeof(buffer) - buffer_ptr)) > 0) buffer_ptr += len;
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                    handle_buffer();
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                }
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                if (fds[0].revents & POLLHUP) {
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                    while (read(STDIN_FILENO, buffer, sizeof(buffer)) > 0);
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                    break;
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                }
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            }
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            if (r == 0 || timeout < 0) {
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                print_top_syscalls(&ss, 5);
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                timeout = 100000;
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            }
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            if (r < 0) break;
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        }
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    }
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    return 0;
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}