Optimize the code that copies strings
authorBart Van Assche <bvanassche@acm.org>
Wed, 14 Aug 2019 20:10:08 +0000 (13:10 -0700)
committerJens Axboe <axboe@kernel.dk>
Wed, 14 Aug 2019 21:01:29 +0000 (15:01 -0600)
Using strncpy() to copy strings is suboptimal because strncpy writes a
bunch of additional unnecessary null bytes. Use snprintf() instead of
strncpy(). An additional advantage of snprintf() is that it guarantees
that the output string is '\0'-terminated.

This patch is an improvement for commit 32e31c8c5f7b ("Fix string copy
compilation warnings").

Cc: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
14 files changed:
cconv.c
client.c
diskutil.c
engines/net.c
engines/sg.c
filesetup.c
gclient.c
init.c
ioengines.c
options.c
parse.c
server.c
stat.c
verify.c

diff --git a/cconv.c b/cconv.c
index 50e45c6..0e65724 100644 (file)
--- a/cconv.c
+++ b/cconv.c
@@ -13,10 +13,9 @@ static void string_to_cpu(char **dst, const uint8_t *src)
 
 static void __string_to_net(uint8_t *dst, const char *src, size_t dst_size)
 {
-       if (src) {
-               dst[dst_size - 1] = '\0';
-               strncpy((char *) dst, src, dst_size - 1);
-       } else
+       if (src)
+               snprintf((char *) dst, dst_size, "%s", src);
+       else
                dst[0] = '\0';
 }
 
index 43cfbd4..e0047af 100644 (file)
--- a/client.c
+++ b/client.c
@@ -520,7 +520,7 @@ static void probe_client(struct fio_client *client)
 
        sname = server_name(client, buf, sizeof(buf));
        memset(pdu.server, 0, sizeof(pdu.server));
-       strncpy((char *) pdu.server, sname, sizeof(pdu.server) - 1);
+       snprintf((char *) pdu.server, sizeof(pdu.server), "%s", sname);
 
        fio_net_send_cmd(client->fd, FIO_NET_CMD_PROBE, &pdu, sizeof(pdu), &tag, &client->cmd_list);
 }
@@ -574,7 +574,8 @@ static int fio_client_connect_sock(struct fio_client *client)
 
        memset(addr, 0, sizeof(*addr));
        addr->sun_family = AF_UNIX;
-       strncpy(addr->sun_path, client->hostname, sizeof(addr->sun_path) - 1);
+       snprintf(addr->sun_path, sizeof(addr->sun_path), "%s",
+                client->hostname);
 
        fd = socket(AF_UNIX, SOCK_STREAM, 0);
        if (fd < 0) {
index 7be4c02..f074401 100644 (file)
@@ -181,8 +181,7 @@ static int get_device_numbers(char *file_name, int *maj, int *min)
                /*
                 * must be a file, open "." in that path
                 */
-               tempname[PATH_MAX - 1] = '\0';
-               strncpy(tempname, file_name, PATH_MAX - 1);
+               snprintf(tempname, ARRAY_SIZE(tempname), "%s", file_name);
                p = dirname(tempname);
                if (stat(p, &st)) {
                        perror("disk util stat");
@@ -314,7 +313,8 @@ static struct disk_util *disk_util_add(struct thread_data *td, int majdev,
                sfree(du);
                return NULL;
        }
-       strncpy((char *) du->dus.name, basename(path), FIO_DU_NAME_SZ - 1);
+       snprintf((char *) du->dus.name, ARRAY_SIZE(du->dus.name), "%s",
+                basename(path));
        du->sysfs_root = strdup(path);
        du->major = majdev;
        du->minor = mindev;
@@ -435,8 +435,7 @@ static struct disk_util *__init_per_file_disk_util(struct thread_data *td,
                        log_err("unknown sysfs layout\n");
                        return NULL;
                }
-               tmp[PATH_MAX - 1] = '\0';
-               strncpy(tmp, p, PATH_MAX - 1);
+               snprintf(tmp, ARRAY_SIZE(tmp), "%s", p);
                sprintf(path, "%s", tmp);
        }
 
index ca6fb34..91f2577 100644 (file)
@@ -1105,8 +1105,7 @@ static int fio_netio_setup_connect_unix(struct thread_data *td,
        struct sockaddr_un *soun = &nd->addr_un;
 
        soun->sun_family = AF_UNIX;
-       memset(soun->sun_path, 0, sizeof(soun->sun_path));
-       strncpy(soun->sun_path, path, sizeof(soun->sun_path) - 1);
+       snprintf(soun->sun_path, sizeof(soun->sun_path), "%s", path);
        return 0;
 }
 
@@ -1135,9 +1134,8 @@ static int fio_netio_setup_listen_unix(struct thread_data *td, const char *path)
 
        mode = umask(000);
 
-       memset(addr, 0, sizeof(*addr));
        addr->sun_family = AF_UNIX;
-       strncpy(addr->sun_path, path, sizeof(addr->sun_path) - 1);
+       snprintf(addr->sun_path, sizeof(addr->sun_path), "%s", path);
        unlink(path);
 
        len = sizeof(addr->sun_family) + strlen(path) + 1;
index c46b9ab..a1a6de4 100644 (file)
@@ -1181,8 +1181,8 @@ static char *fio_sgio_errdetails(struct io_u *io_u)
        }
 
        if (!(hdr->info & SG_INFO_CHECK) && !strlen(msg))
-               strncpy(msg, "SG Driver did not report a Host, Driver or Device check",
-                       MAXERRDETAIL - 1);
+               snprintf(msg, MAXERRDETAIL, "%s",
+                        "SG Driver did not report a Host, Driver or Device check");
 
        return msg;
 }
index 17fa31f..57eca1b 100644 (file)
@@ -805,8 +805,7 @@ static unsigned long long get_fs_free_counts(struct thread_data *td)
                } else if (f->filetype != FIO_TYPE_FILE)
                        continue;
 
-               buf[255] = '\0';
-               strncpy(buf, f->file_name, 255);
+               snprintf(buf, ARRAY_SIZE(buf), "%s", f->file_name);
 
                if (stat(buf, &sb) < 0) {
                        if (errno != ENOENT)
@@ -829,8 +828,7 @@ static unsigned long long get_fs_free_counts(struct thread_data *td)
                        continue;
 
                fm = calloc(1, sizeof(*fm));
-               strncpy(fm->__base, buf, sizeof(fm->__base));
-               fm->__base[255] = '\0'; 
+               snprintf(fm->__base, ARRAY_SIZE(fm->__base), "%s", buf);
                fm->base = basename(fm->__base);
                fm->key = sb.st_dev;
                flist_add(&fm->list, &list);
index 04275a1..6432417 100644 (file)
--- a/gclient.c
+++ b/gclient.c
@@ -318,7 +318,7 @@ static void gfio_update_thread_status(struct gui_entry *ge,
        static char message[100];
        const char *m = message;
 
-       strncpy(message, status_message, sizeof(message) - 1);
+       snprintf(message, sizeof(message), "%s", status_message);
        gtk_progress_bar_set_text(GTK_PROGRESS_BAR(ge->thread_status_pb), m);
        gtk_progress_bar_set_fraction(GTK_PROGRESS_BAR(ge->thread_status_pb), perc / 100.0);
        gtk_widget_queue_draw(ge->ui->window);
@@ -330,7 +330,7 @@ static void gfio_update_thread_status_all(struct gui *ui, char *status_message,
        static char message[100];
        const char *m = message;
 
-       strncpy(message, status_message, sizeof(message) - 1);
+       strncpy(message, sizeof(message), "%s", status_message);
        gtk_progress_bar_set_text(GTK_PROGRESS_BAR(ui->thread_status_pb), m);
        gtk_progress_bar_set_fraction(GTK_PROGRESS_BAR(ui->thread_status_pb), perc / 100.0);
        gtk_widget_queue_draw(ui->window);
diff --git a/init.c b/init.c
index c9f6198..63f2168 100644 (file)
--- a/init.c
+++ b/init.c
@@ -1273,8 +1273,7 @@ static char *make_filename(char *buf, size_t buf_size,struct thread_options *o,
        for (f = &fpre_keywords[0]; f->keyword; f++)
                f->strlen = strlen(f->keyword);
 
-       buf[buf_size - 1] = '\0';
-       strncpy(buf, o->filename_format, buf_size - 1);
+       snprintf(buf, buf_size, "%s", o->filename_format);
 
        memset(copy, 0, sizeof(copy));
        for (f = &fpre_keywords[0]; f->keyword; f++) {
@@ -1353,7 +1352,7 @@ static char *make_filename(char *buf, size_t buf_size,struct thread_options *o,
                        if (post_start)
                                strncpy(dst, buf + post_start, dst_left);
 
-                       strncpy(buf, copy, buf_size - 1);
+                       snprintf(buf, buf_size, "%s", copy);
                } while (1);
        }
 
@@ -2029,20 +2028,12 @@ static int __parse_jobs_ini(struct thread_data *td,
                                 */
                                if (access(filename, F_OK) &&
                                    (ts = strrchr(file, '/'))) {
-                                       int len = ts - file +
-                                               strlen(filename) + 2;
-
-                                       if (!(full_fn = calloc(1, len))) {
+                                       if (asprintf(&full_fn, "%.*s%s",
+                                                (int)(ts - file + 1), file,
+                                                filename) < 0) {
                                                ret = ENOMEM;
                                                break;
                                        }
-
-                                       strncpy(full_fn,
-                                               file, (ts - file) + 1);
-                                       strncpy(full_fn + (ts - file) + 1,
-                                               filename,
-                                               len - (ts - file) - 1);
-                                       full_fn[len - 1] = 0;
                                        filename = full_fn;
                                }
 
index aa4ccd2..40fa75c 100644 (file)
@@ -125,8 +125,7 @@ static struct ioengine_ops *__load_ioengine(const char *name)
 {
        char engine[64];
 
-       engine[sizeof(engine) - 1] = '\0';
-       strncpy(engine, name, sizeof(engine) - 1);
+       snprintf(engine, sizeof(engine), "%s", name);
 
        /*
         * linux libaio has alias names, so convert to what we want
index f4c9bed..447f231 100644 (file)
--- a/options.c
+++ b/options.c
@@ -4902,8 +4902,7 @@ char *fio_option_dup_subs(const char *opt)
                return NULL;
        }
 
-       in[OPT_LEN_MAX] = '\0';
-       strncpy(in, opt, OPT_LEN_MAX);
+       snprintf(in, sizeof(in), "%s", opt);
 
        while (*inptr && nchr > 0) {
                if (inptr[0] == '$' && inptr[1] == '{') {
diff --git a/parse.c b/parse.c
index a7d4516..c4fd462 100644 (file)
--- a/parse.c
+++ b/parse.c
@@ -602,8 +602,7 @@ static int __handle_option(const struct fio_option *o, const char *ptr,
                if (!is_time && o->is_time)
                        is_time = o->is_time;
 
-               tmp[sizeof(tmp) - 1] = '\0';
-               strncpy(tmp, ptr, sizeof(tmp) - 1);
+               snprintf(tmp, sizeof(tmp), "%s", ptr);
                p = strchr(tmp, ',');
                if (p)
                        *p = '\0';
@@ -829,8 +828,7 @@ static int __handle_option(const struct fio_option *o, const char *ptr,
                char tmp[128];
                char *p1, *p2;
 
-               tmp[sizeof(tmp) - 1] = '\0';
-               strncpy(tmp, ptr, sizeof(tmp) - 1);
+               snprintf(tmp, sizeof(tmp), "%s", ptr);
 
                /* Handle bsrange with separate read,write values: */
                p1 = strchr(tmp, ',');
index 23e549a..e784622 100644 (file)
--- a/server.c
+++ b/server.c
@@ -865,7 +865,8 @@ static int handle_probe_cmd(struct fio_net_cmd *cmd)
        strcpy(me, (char *) pdu->server);
 
        gethostname((char *) probe.hostname, sizeof(probe.hostname));
-       strncpy((char *) probe.fio_version, fio_version_string, sizeof(probe.fio_version) - 1);
+       snprintf((char *) probe.fio_version, sizeof(probe.fio_version), "%s",
+                fio_version_string);
 
        /*
         * If the client supports compression and we do too, then enable it
@@ -1470,12 +1471,10 @@ void fio_server_send_ts(struct thread_stat *ts, struct group_run_stats *rs)
 
        memset(&p, 0, sizeof(p));
 
-       strncpy(p.ts.name, ts->name, FIO_JOBNAME_SIZE);
-       p.ts.name[FIO_JOBNAME_SIZE - 1] = '\0';
-       strncpy(p.ts.verror, ts->verror, FIO_VERROR_SIZE);
-       p.ts.verror[FIO_VERROR_SIZE - 1] = '\0';
-       strncpy(p.ts.description, ts->description, FIO_JOBDESC_SIZE);
-       p.ts.description[FIO_JOBDESC_SIZE - 1] = '\0';
+       snprintf(p.ts.name, sizeof(p.ts.name), "%s", ts->name);
+       snprintf(p.ts.verror, sizeof(p.ts.verror), "%s", ts->verror);
+       snprintf(p.ts.description, sizeof(p.ts.description), "%s",
+                ts->description);
 
        p.ts.error              = cpu_to_le32(ts->error);
        p.ts.thread_number      = cpu_to_le32(ts->thread_number);
@@ -1666,8 +1665,7 @@ static void convert_dus(struct disk_util_stat *dst, struct disk_util_stat *src)
 {
        int i;
 
-       dst->name[FIO_DU_NAME_SZ - 1] = '\0';
-       strncpy((char *) dst->name, (char *) src->name, FIO_DU_NAME_SZ - 1);
+       snprintf((char *) dst->name, sizeof(dst->name), "%s", src->name);
 
        for (i = 0; i < 2; i++) {
                dst->s.ios[i]           = cpu_to_le64(src->s.ios[i]);
@@ -1977,8 +1975,7 @@ int fio_send_iolog(struct thread_data *td, struct io_log *log, const char *name)
        else
                pdu.compressed = 0;
 
-       strncpy((char *) pdu.name, name, FIO_NET_NAME_MAX);
-       pdu.name[FIO_NET_NAME_MAX - 1] = '\0';
+       snprintf((char *) pdu.name, sizeof(pdu.name), "%s", name);
 
        /*
         * We can't do this for a pre-compressed log, but for that case,
@@ -2195,9 +2192,8 @@ static int fio_init_server_sock(void)
 
        mode = umask(000);
 
-       memset(&addr, 0, sizeof(addr));
        addr.sun_family = AF_UNIX;
-       strncpy(addr.sun_path, bind_sock, sizeof(addr.sun_path) - 1);
+       snprintf(addr.sun_path, sizeof(addr.sun_path), "%s", bind_sock);
 
        len = sizeof(addr.sun_family) + strlen(bind_sock) + 1;
 
@@ -2247,9 +2243,9 @@ static int fio_init_server_connection(void)
                if (p)
                        strcat(p, port);
                else
-                       strncpy(bind_str, port, sizeof(bind_str) - 1);
+                       snprintf(bind_str, sizeof(bind_str), "%s", port);
        } else
-               strncpy(bind_str, bind_sock, sizeof(bind_str) - 1);
+               snprintf(bind_str, sizeof(bind_str), "%s", bind_sock);
 
        log_info("fio: server listening on %s\n", bind_str);
 
diff --git a/stat.c b/stat.c
index bf87917..3363790 100644 (file)
--- a/stat.c
+++ b/stat.c
@@ -1828,10 +1828,11 @@ void __show_run_stats(void)
                        /*
                         * These are per-group shared already
                         */
-                       strncpy(ts->name, td->o.name, FIO_JOBNAME_SIZE - 1);
+                       snprintf(ts->name, sizeof(ts->name), "%s", td->o.name);
                        if (td->o.description)
-                               strncpy(ts->description, td->o.description,
-                                               FIO_JOBDESC_SIZE - 1);
+                               snprintf(ts->description,
+                                        sizeof(ts->description), "%s",
+                                        td->o.description);
                        else
                                memset(ts->description, 0, FIO_JOBDESC_SIZE);
 
@@ -1868,12 +1869,12 @@ void __show_run_stats(void)
                        if (!td->error && td->o.continue_on_error &&
                            td->first_error) {
                                ts->error = td->first_error;
-                               ts->verror[sizeof(ts->verror) - 1] = '\0';
-                               strncpy(ts->verror, td->verror, sizeof(ts->verror) - 1);
+                               snprintf(ts->verror, sizeof(ts->verror), "%s",
+                                        td->verror);
                        } else  if (td->error) {
                                ts->error = td->error;
-                               ts->verror[sizeof(ts->verror) - 1] = '\0';
-                               strncpy(ts->verror, td->verror, sizeof(ts->verror) - 1);
+                               snprintf(ts->verror, sizeof(ts->verror), "%s",
+                                        td->verror);
                        }
                }
 
index f79ab43..48ba051 100644 (file)
--- a/verify.c
+++ b/verify.c
@@ -1635,8 +1635,7 @@ struct all_io_list *get_all_io_list(int save_mask, size_t *sz)
                        s->rand.state32.s[3] = 0;
                        s->rand.use64 = 0;
                }
-               s->name[sizeof(s->name) - 1] = '\0';
-               strncpy((char *) s->name, td->o.name, sizeof(s->name) - 1);
+               snprintf((char *) s->name, sizeof(s->name), "%s", td->o.name);
                next = io_list_next(s);
        }