/* SPDX-License-Identifier: GPL-2.0 */
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <linux/ctype.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/zalloc.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <subcmd/exec-cmd.h>
#include <subcmd/parse-options.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <api/io.h>
#include "builtin.h"
#include "tests-scripts.h"
#include "color.h"
#include "debug.h"
#include "hist.h"
#include "intlist.h"
#include "string2.h"
#include "symbol.h"
#include "tests.h"
#include "util/rlimit.h"
#include "util/util.h"

static int shell_tests__dir_fd(void)
{
        struct stat st;
        char path[PATH_MAX], path2[PATH_MAX], *exec_path;
        ssize_t len;
        static const char * const devel_dirs[] = {
                "./tools/perf/tests/shell",
                "./tests/shell",
                "./source/tests/shell"
        };
        int fd;
        char *p;

        for (size_t i = 0; i < ARRAY_SIZE(devel_dirs); ++i) {
                fd = open(devel_dirs[i], O_PATH);

                if (fd >= 0)
                        return fd;
        }

        /* Use directory of executable */
        len = readlink("/proc/self/exe", path2, sizeof(path2) - 1);
        if (len < 0)
                return -1;
        path2[len] = '\0';
        /* Follow another level of symlink if there */
        if (lstat(path2, &st) == 0 && (st.st_mode & S_IFMT) == S_IFLNK) {
                scnprintf(path, sizeof(path), "%s", path2);
                len = readlink(path, path2, sizeof(path2) - 1);
                if (len < 0)
                        return -1;
                path2[len] = '\0';
        }
        /* Get directory */
        p = strrchr(path2, '/');
        if (p)
                *p = 0;
        scnprintf(path, sizeof(path), "%s/tests/shell", path2);
        fd = open(path, O_PATH);
        if (fd >= 0)
                return fd;
        scnprintf(path, sizeof(path), "%s/source/tests/shell", path2);
        fd = open(path, O_PATH);
        if (fd >= 0)
                return fd;

        /* Then installed path. */
        exec_path = get_argv_exec_path();
        scnprintf(path, sizeof(path), "%s/tests/shell", exec_path);
        free(exec_path);
        return open(path, O_PATH);
}

static char *shell_test__description(int dir_fd, const char *name)
{
        struct io io;
        char buf[128], *line = NULL;
        size_t line_len = 0;
        ssize_t len;
        char *desc = NULL;
        const char *spdx = "SPDX-License";

        io__init(&io, openat(dir_fd, name, O_RDONLY), buf, sizeof(buf));
        if (io.fd < 0)
                return NULL;

        while ((len = io__getline(&io, &line, &line_len)) > 0) {
                char *p = line;

                /* Skip leading whitespace */
                while (*p && isspace(*p))
                        p++;

                /* Must be a comment */
                if (*p != '#')
                        continue;
                p++;

                /* Skip shebang or SPDX lines */
                if (*p == '!' || (strstr(p, spdx) && strstr(p, "-Identifier:")))
                        continue;

                /* Skip whitespace after # */
                while (*p && isspace(*p))
                        p++;

                /* If we found non-empty text, this is the description! */
                if (*p && *p != '\n') {
                        char *end = p + strlen(p);

                        while (end > p && isspace(end[-1]))
                                end--;
                        *end = '\0';
                        desc = strdup(p);
                        break;
                }
        }
        free(line);
        close(io.fd);
        return desc;
}

/* Is this full file path a shell script */
static bool is_shell_script(int dir_fd, const char *path)
{
        const char *ext;

        ext = strrchr(path, '.');
        if (!ext)
                return false;
        if (!strcmp(ext, ".sh")) { /* Has .sh extension */
                if (faccessat(dir_fd, path, R_OK | X_OK, 0) == 0) /* Is executable */
                        return true;
        }
        return false;
}

/* Is this file in this dir a shell script (for test purposes) */
static bool is_test_script(int dir_fd, const char *name)
{
        return is_shell_script(dir_fd, name);
}

/* Duplicate a string and fall over and die if we run out of memory */
static char *strdup_check(const char *str)
{
        char *newstr;

        newstr = strdup(str);
        if (!newstr) {
                pr_err("Out of memory while duplicating test script string\n");
                abort();
        }
        return newstr;
}

static int shell_test__run(struct test_suite *test, int subtest __maybe_unused)
{
        const char *file = test->priv;
        int err;
        char *cmd = NULL;

        if (asprintf(&cmd, "%s%s", file, verbose ? " -v" : "") < 0)
                return TEST_FAIL;
        err = system(cmd);
        free(cmd);
        if (!err)
                return TEST_OK;

        return WEXITSTATUS(err) == 2 ? TEST_SKIP : TEST_FAIL;
}

static void append_script(int dir_fd, const char *name, char *desc,
                          struct test_suite ***result,
                          size_t *result_sz)
{
        char filename[PATH_MAX], link[128];
        struct test_suite *test_suite, **result_tmp;
        struct test_case *tests;
        ssize_t len;
        char *exclusive;

        snprintf(link, sizeof(link), "/proc/%d/fd/%d", getpid(), dir_fd);
        len = readlink(link, filename, sizeof(filename) - 1);
        if (len < 0 || (size_t)len > sizeof(filename) - strlen(name) - 2) {
                pr_err("Failed to readlink %s or path too long", link);
                return;
        }
        filename[len++] = '/';
        strcpy(&filename[len], name);

        tests = calloc(2, sizeof(*tests));
        if (!tests) {
                pr_err("Out of memory while building script test suite list\n");
                return;
        }
        tests[0].name = strdup_check(name);
        exclusive = strstr(desc, " (exclusive)");
        if (exclusive != NULL) {
                tests[0].exclusive = true;
                exclusive[0] = '\0';
        }
        tests[0].desc = strdup_check(desc);
        tests[0].run_case = shell_test__run;
        test_suite = zalloc(sizeof(*test_suite));
        if (!test_suite) {
                pr_err("Out of memory while building script test suite list\n");
                free(tests);
                return;
        }
        test_suite->desc = desc;
        test_suite->test_cases = tests;
        test_suite->priv = strdup_check(filename);
        /* Realloc is good enough, though we could realloc by chunks, not that
         * anyone will ever measure performance here */
        result_tmp = realloc(*result, (*result_sz + 1) * sizeof(*result_tmp));
        if (result_tmp == NULL) {
                pr_err("Out of memory while building script test suite list\n");
                free(tests);
                free(test_suite);
                return;
        }
        /* Add file to end and NULL terminate the struct array */
        *result = result_tmp;
        (*result)[*result_sz] = test_suite;
        (*result_sz)++;
}

static void append_scripts_in_dir(int dir_fd,
                                  struct test_suite ***result,
                                  size_t *result_sz)
{
        struct dirent **entlist;
        struct dirent *ent;
        int n_dirs, i;

        /* List files, sorted by alpha */
        n_dirs = scandirat(dir_fd, ".", &entlist, NULL, alphasort);
        if (n_dirs == -1)
                return;
        for (i = 0; i < n_dirs && (ent = entlist[i]); i++) {
                int fd;

                if (ent->d_name[0] == '.')
                        continue; /* Skip hidden files */
                if (is_test_script(dir_fd, ent->d_name)) { /* It's a test */
                        char *desc = shell_test__description(dir_fd, ent->d_name);

                        if (desc) /* It has a desc line - valid script */
                                append_script(dir_fd, ent->d_name, desc, result, result_sz);
                        continue;
                }
                if (ent->d_type != DT_DIR) {
                        struct stat st;

                        if (ent->d_type != DT_UNKNOWN)
                                continue;
                        fstatat(dir_fd, ent->d_name, &st, 0);
                        if (!S_ISDIR(st.st_mode))
                                continue;
                }
                if (strncmp(ent->d_name, "base_", 5) == 0)
                        continue; /* Skip scripts that have a separate driver. */
                fd = openat(dir_fd, ent->d_name, O_PATH);
                append_scripts_in_dir(fd, result, result_sz);
                close(fd);
        }
        for (i = 0; i < n_dirs; i++) /* Clean up */
                zfree(&entlist[i]);
        free(entlist);
}

struct test_suite **create_script_test_suites(void)
{
        struct test_suite **result = NULL, **result_tmp;
        size_t result_sz = 0;
        int dir_fd = shell_tests__dir_fd(); /* Walk  dir */

        /*
         * Append scripts if fd is good, otherwise return a NULL terminated zero
         * length array.
         */
        if (dir_fd >= 0)
                append_scripts_in_dir(dir_fd, &result, &result_sz);

        result_tmp = realloc(result, (result_sz + 1) * sizeof(*result_tmp));
        if (result_tmp == NULL) {
                pr_err("Out of memory while building script test suite list\n");
                abort();
        }
        /* NULL terminate the test suite array. */
        result = result_tmp;
        result[result_sz] = NULL;
        if (dir_fd >= 0)
                close(dir_fd);
        return result;
}