It makes the code clearer and less error prone.

clearer:
- less code
- the code is now using the same format to create strings dynamically

less error prone:
- no magic number +2 +9 +5 to compute the size
- no copy&paste of the strings to compute the size and to concatenate

The function `asprintf` is not POSIX standard but the program
was already using it. Later it can be decided to use only POSIX
functions, then we can easly replace all the `asprintf(3)` with a local
implementation of that function.

Signed-off-by: Federico Vaga <federico.v...@vaga.pv.it>
---
 event-plugin.c   | 24 ++++++---------
 parse-filter.c   | 11 +++----
 trace-list.c     |  8 ++---
 trace-output.c   |  6 ++--
 trace-record.c   | 93 +++++++++++++++++++++++++++++---------------------------
 trace-recorder.c | 11 +++----
 trace-show.c     |  8 ++---
 trace-split.c    |  7 +++--
 trace-stat.c     |  7 +++--
 trace-util.c     | 62 ++++++++++++++++---------------------
 10 files changed, 112 insertions(+), 125 deletions(-)

diff --git a/event-plugin.c b/event-plugin.c
index a16756a..d542cb6 100644
--- a/event-plugin.c
+++ b/event-plugin.c
@@ -120,12 +120,12 @@ char **traceevent_plugin_list_options(void)
                for (op = reg->options; op->name; op++) {
                        char *alias = op->plugin_alias ? op->plugin_alias : 
op->file;
                        char **temp = list;
+                       int ret;
 
-                       name = malloc(strlen(op->name) + strlen(alias) + 2);
-                       if (!name)
+                       ret = asprintf(&name, "%s:%s", alias, op->name);
+                       if (ret < 0)
                                goto err;
 
-                       sprintf(name, "%s:%s", alias, op->name);
                        list = realloc(list, count + 2);
                        if (!list) {
                                list = temp;
@@ -290,17 +290,14 @@ load_plugin(struct pevent *pevent, const char *path,
        const char *alias;
        char *plugin;
        void *handle;
+       int ret;
 
-       plugin = malloc(strlen(path) + strlen(file) + 2);
-       if (!plugin) {
+       ret = asprintf(&plugin, "%s/%s", path, file);
+       if (ret < 0) {
                warning("could not allocate plugin memory\n");
                return;
        }
 
-       strcpy(plugin, path);
-       strcat(plugin, "/");
-       strcat(plugin, file);
-
        handle = dlopen(plugin, RTLD_NOW | RTLD_GLOBAL);
        if (!handle) {
                warning("could not load plugin '%s'\n%s\n",
@@ -391,6 +388,7 @@ load_plugins(struct pevent *pevent, const char *suffix,
        char *home;
        char *path;
        char *envdir;
+       int ret;
 
        if (pevent->flags & PEVENT_DISABLE_PLUGINS)
                return;
@@ -421,16 +419,12 @@ load_plugins(struct pevent *pevent, const char *suffix,
        if (!home)
                return;
 
-       path = malloc(strlen(home) + strlen(LOCAL_PLUGIN_DIR) + 2);
-       if (!path) {
+       ret = asprintf(&path, "%s/%s", home, LOCAL_PLUGIN_DIR);
+       if (ret < 0) {
                warning("could not allocate plugin memory\n");
                return;
        }
 
-       strcpy(path, home);
-       strcat(path, "/");
-       strcat(path, LOCAL_PLUGIN_DIR);
-
        load_plugins_dir(pevent, suffix, path, load_plugin, data);
 
        free(path);
diff --git a/parse-filter.c b/parse-filter.c
index 8e302c4..ebf2a95 100644
--- a/parse-filter.c
+++ b/parse-filter.c
@@ -287,12 +287,10 @@ find_event(struct pevent *pevent, struct event_list 
**events,
                sys_name = NULL;
        }
 
-       reg = malloc(strlen(event_name) + 3);
-       if (reg == NULL)
+       ret = asprintf(&reg, "^%s$", event_name);
+       if (ret < 0)
                return PEVENT_ERRNO__MEM_ALLOC_FAILED;
 
-       sprintf(reg, "^%s$", event_name);
-
        ret = regcomp(&ereg, reg, REG_ICASE|REG_NOSUB);
        free(reg);
 
@@ -300,13 +298,12 @@ find_event(struct pevent *pevent, struct event_list 
**events,
                return PEVENT_ERRNO__INVALID_EVENT_NAME;
 
        if (sys_name) {
-               reg = malloc(strlen(sys_name) + 3);
-               if (reg == NULL) {
+               ret = asprintf(&reg, "^%s$", sys_name);
+               if (ret < 0) {
                        regfree(&ereg);
                        return PEVENT_ERRNO__MEM_ALLOC_FAILED;
                }
 
-               sprintf(reg, "^%s$", sys_name);
                ret = regcomp(&sreg, reg, REG_ICASE|REG_NOSUB);
                free(reg);
                if (ret) {
diff --git a/trace-list.c b/trace-list.c
index 293635f..32b19bc 100644
--- a/trace-list.c
+++ b/trace-list.c
@@ -133,6 +133,7 @@ static char *get_event_file(const char *type, char *buf, 
int len)
        char *event;
        char *path;
        char *file;
+       int ret;
 
        if (buf[len-1] == '\n')
                buf[len-1] = '\0';
@@ -146,11 +147,10 @@ static char *get_event_file(const char *type, char *buf, 
int len)
                die("no event found in %s\n", buf);
 
        path = tracecmd_get_tracing_file("events");
-       file = malloc(strlen(path) + strlen(system) + strlen(event) +
-                     strlen(type) + strlen("///") + 1);
-       if (!file)
+       ret = asprintf(&file, "%s/%s/%s/%s", path, system, event, type);
+       if (ret < 0)
                die("Failed to allocate event file %s %s", system, event);
-       sprintf(file, "%s/%s/%s/%s", path, system, event, type);
+
        tracecmd_put_tracing_file(path);
 
        return file;
diff --git a/trace-output.c b/trace-output.c
index bfe6331..26ed560 100644
--- a/trace-output.c
+++ b/trace-output.c
@@ -234,16 +234,16 @@ static char *get_tracing_file(struct tracecmd_output 
*handle, const char *name)
 {
        const char *tracing;
        char *file;
+       int ret;
 
        tracing = find_tracing_dir(handle);
        if (!tracing)
                return NULL;
 
-       file = malloc(strlen(tracing) + strlen(name) + 2);
-       if (!file)
+       ret = asprintf(&file, "%s/%s", tracing, name);
+       if (ret < 0)
                return NULL;
 
-       sprintf(file, "%s/%s", tracing, name);
        return file;
 }
 
diff --git a/trace-record.c b/trace-record.c
index 020a373..748dd46 100644
--- a/trace-record.c
+++ b/trace-record.c
@@ -45,6 +45,7 @@
 #include <glob.h>
 #include <errno.h>
 #include <limits.h>
+#include <libgen.h>
 
 #include "trace-local.h"
 #include "trace-msg.h"
@@ -723,14 +724,12 @@ get_instance_file(struct buffer_instance *instance, const 
char *file)
 {
        char *buf;
        char *path;
+       int ret;
 
        if (instance->name) {
-               buf = malloc(strlen(instance->name) +
-                            strlen(file) + strlen("instances//") + 1);
-               if (!buf)
+               ret = asprintf(&buf, "instances/%s/%s", instance->name, file);
+               if (ret < 0)
                        die("Failed to allocate name for %s/%s", 
instance->name, file);
-               sprintf(buf, "instances/%s/%s", instance->name, file);
-
                path = tracecmd_get_tracing_file(buf);
                free(buf);
        } else
@@ -744,17 +743,15 @@ get_instance_dir(struct buffer_instance *instance)
 {
        char *buf;
        char *path;
+       int ret;
 
        /* only works for instances */
        if (!instance->name)
                return NULL;
 
-       buf = malloc(strlen(instance->name) +
-                    strlen("instances/") + 1);
-       if (!buf)
+       ret = asprintf(&buf, "instances/%s", instance->name);
+       if (ret < 0)
                die("Failed to allocate for instance %s", instance->name);
-       sprintf(buf, "instances/%s", instance->name);
-
        path = tracecmd_get_tracing_file(buf);
        free(buf);
 
@@ -2215,14 +2212,28 @@ static void set_max_graph_depth(struct buffer_instance 
*instance, char *max_grap
                die("could not write to max_graph_depth");
 }
 
+
+/**
+ * create_event - create and event descriptor
+ * @instance: instance to use
+ * @path: path to event attribute
+ * @old_event: event descriptor to use as base
+ *
+ * NOTE: the function purpose is to create a data structure to describe
+ * an ftrace event. During the process it becomes handy to change the
+ * string `path`. So, do not rely on the content of `path` after you
+ * invoke this function.
+ */
 static struct event_list *
 create_event(struct buffer_instance *instance, char *path, struct event_list 
*old_event)
 {
        struct event_list *event;
        struct stat st;
-       char *p;
+       char *p, *path_dirname;
        int ret;
 
+       path_dirname = dirname(path);
+
        event = malloc(sizeof(*event));
        if (!event)
                die("Failed to allocate event");
@@ -2234,14 +2245,10 @@ create_event(struct buffer_instance *instance, char 
*path, struct event_list *ol
                if (!event->filter_file)
                        die("malloc filter file");
        }
-       for (p = path + strlen(path) - 1; p > path; p--)
-               if (*p == '/')
-                       break;
-       *p = '\0';
-       p = malloc(strlen(path) + strlen("/enable") + 1);
-       if (!p)
-               die("Failed to allocate enable path for %s", path);
-       sprintf(p, "%s/enable", path);
+
+       ret = asprintf(&p, "%s/enable", path_dirname);
+       if (ret < 0)
+               die("Failed to allocate enable path for %s", path_dirname);
        ret = stat(p, &st);
        if (ret >= 0)
                event->enable_file = p;
@@ -2249,10 +2256,9 @@ create_event(struct buffer_instance *instance, char 
*path, struct event_list *ol
                free(p);
 
        if (event->trigger) {
-               p = malloc(strlen(path) + strlen("/trigger") + 1);
-               if (!p)
-                       die("Failed to allocate trigger path for %s", path);
-               sprintf(p, "%s/trigger", path);
+               ret = asprintf(&p, "%s/trigger", path_dirname);
+               if (ret < 0)
+                       die("Failed to allocate trigger path for %s", 
path_dirname);
                ret = stat(p, &st);
                if (ret > 0)
                        die("trigger specified but not supported by this 
kernel");
@@ -2266,22 +2272,24 @@ static void make_sched_event(struct buffer_instance 
*instance,
                             struct event_list **event, struct event_list 
*sched,
                             const char *sched_path)
 {
-       char *path;
-       char *p;
+       char *path, *sched_filter_file_tmp;
+       int ret;
 
        /* Do nothing if the event already exists */
        if (*event)
                return;
 
-       path = malloc(strlen(sched->filter_file) + strlen(sched_path) + 2);
-       if (!path)
+       /* we do not want to corrupt sched->filter_file when using dirname() */
+       sched_filter_file_tmp = strdup(sched->filter_file);
+       if (!sched_filter_file_tmp)
                die("Failed to allocate path for %s", sched_path);
 
-       sprintf(path, "%s", sched->filter_file);
-
-       /* Remove the /filter from filter file */
-       p = path + strlen(path) - strlen("filter");
-       sprintf(p, "%s/filter", sched_path);
+       ret = asprintf(&path, "%s/%s/filter",
+                      dirname(sched_filter_file_tmp),
+                      sched_path);
+       free(sched_filter_file_tmp);
+       if (ret < 0)
+               die("Failed to allocate path for %s", sched_path);
 
        *event = create_event(instance, path, sched);
        free(path);
@@ -2310,10 +2318,9 @@ static int expand_event_files(struct buffer_instance 
*instance,
        int ret;
        int i;
 
-       p = malloc(strlen(file) + strlen("events//filter") + 1);
-       if (!p)
+       ret = asprintf(&p, "events/%s/filter", file);
+       if (ret < 0)
                die("Failed to allocate event filter path for %s", file);
-       sprintf(p, "events/%s/filter", file);
 
        path = get_instance_file(instance, p);
 
@@ -3969,6 +3976,8 @@ static int recording_all_events(void)
 
 static void add_trigger(struct event_list *event, const char *trigger)
 {
+       int ret;
+
        if (event->trigger) {
                event->trigger = realloc(event->trigger,
                                         strlen(event->trigger) + strlen("\n") +
@@ -3976,10 +3985,9 @@ static void add_trigger(struct event_list *event, const 
char *trigger)
                strcat(event->trigger, "\n");
                strcat(event->trigger, trigger);
        } else {
-               event->trigger = malloc(strlen(trigger) + 1);
-               if (!event->trigger)
+               ret = asprintf(&event->trigger, "%s", trigger);
+               if (ret < 0)
                        die("Failed to allocate event trigger");
-               sprintf(event->trigger, "%s", trigger);
        }
 }
 
@@ -4373,7 +4381,7 @@ void trace_record (int argc, char **argv)
                usage(argv);
 
        for (;;) {
-               int option_index = 0;
+               int option_index = 0, ret;
                const char *opts;
                static struct option long_options[] = {
                        {"date", no_argument, NULL, OPT_date},
@@ -4438,12 +4446,9 @@ void trace_record (int argc, char **argv)
                                strcat(last_event->filter, optarg);
                                strcat(last_event->filter, ")");
                        } else {
-                               last_event->filter =
-                                       malloc(strlen(optarg) +
-                                              strlen("()") + 1);
-                               if (!last_event->filter)
+                               ret = asprintf(&last_event->filter, "(%s)", 
optarg);
+                               if (ret < 0)
                                        die("Failed to allocate filter %s", 
optarg);
-                               sprintf(last_event->filter, "(%s)", optarg);
                        }
                        break;
 
diff --git a/trace-recorder.c b/trace-recorder.c
index 1b9d364..85150fd 100644
--- a/trace-recorder.c
+++ b/trace-recorder.c
@@ -156,14 +156,13 @@ tracecmd_create_buffer_recorder_fd2(int fd, int fd2, int 
cpu, unsigned flags,
        recorder->fd1 = fd;
        recorder->fd2 = fd2;
 
-       path = malloc(strlen(buffer) + 40);
-       if (!path)
-               goto out_free;
-
        if (flags & TRACECMD_RECORD_SNAPSHOT)
-               sprintf(path, "%s/per_cpu/cpu%d/snapshot_raw", buffer, cpu);
+               ret = asprintf(&path, "%s/per_cpu/cpu%d/snapshot_raw", buffer, 
cpu);
        else
-               sprintf(path, "%s/per_cpu/cpu%d/trace_pipe_raw", buffer, cpu);
+               ret = asprintf(&path, "%s/per_cpu/cpu%d/trace_pipe_raw", 
buffer, cpu);
+       if (ret < 0)
+               goto out_free;
+
        recorder->trace_fd = open(path, O_RDONLY);
        if (recorder->trace_fd < 0)
                goto out_free;
diff --git a/trace-show.c b/trace-show.c
index 14b786c..f13db31 100644
--- a/trace-show.c
+++ b/trace-show.c
@@ -154,11 +154,11 @@ void trace_show(int argc, char **argv)
        }
 
        if (buffer) {
-               path = malloc(strlen(buffer) + strlen("instances//") +
-                             strlen(file) + 1);
-               if (!path)
+               int ret;
+
+               ret = asprintf(&path, "instances/%s/%s", buffer, file);
+               if (ret < 0)
                        die("Failed to allocate instance path %s", file);
-               sprintf(path, "instances/%s/%s", buffer, file);
                file = path;
        }
 
diff --git a/trace-split.c b/trace-split.c
index 87d43ad..5e4ac68 100644
--- a/trace-split.c
+++ b/trace-split.c
@@ -369,10 +369,11 @@ static double parse_file(struct tracecmd_input *handle,
                die("Failed to allocate cpu_data for %d cpus", cpus);
 
        for (cpu = 0; cpu < cpus; cpu++) {
-               file = malloc(strlen(output_file) + 50);
-               if (!file)
+               int ret;
+
+               ret = asprintf(&file, "%s/.tmp.%s.%d", dir, base, cpu);
+               if (ret < 0)
                        die("Failed to allocate file for %s %s %d", dir, base, 
cpu);
-               sprintf(file, "%s/.tmp.%s.%d", dir, base, cpu);
                fd = open(file, O_WRONLY | O_CREAT | O_TRUNC | O_LARGEFILE, 
0644);
                cpu_data[cpu].cpu = cpu;
                cpu_data[cpu].fd = fd;
diff --git a/trace-stat.c b/trace-stat.c
index adbf3c3..fd16354 100644
--- a/trace-stat.c
+++ b/trace-stat.c
@@ -70,15 +70,16 @@ char *strstrip(char *str)
        return s;
 }
 
+/* FIXME: append_file() is duplicated and could be consolidated */
 char *append_file(const char *dir, const char *name)
 {
        char *file;
+       int ret;
 
-       file = malloc(strlen(dir) + strlen(name) + 2);
-       if (!file)
+       ret = asprintf(&file, "%s/%s", dir, name);
+       if (ret < 0)
                die("Failed to allocate %s/%s", dir, name);
 
-       sprintf(file, "%s/%s", dir, name);
        return file;
 }
 
diff --git a/trace-util.c b/trace-util.c
index d464a61..45fa95a 100644
--- a/trace-util.c
+++ b/trace-util.c
@@ -85,14 +85,15 @@ char **trace_util_list_plugin_options(void)
        for (reg = registered_options; reg; reg = reg->next) {
                for (op = reg->options; op->name; op++) {
                        char *alias = op->plugin_alias ? op->plugin_alias : 
op->file;
+                       int ret;
 
-                       name = malloc(strlen(op->name) + strlen(alias) + 2);
-                       if (!name) {
+                       ret = asprintf(&name, "%s:%s", alias, op->name);
+                       if (ret < 0) {
                                warning("Failed to allocate plugin option 
%s:%s",
                                        alias, op->name);
                                break;
                        }
-                       sprintf(name, "%s:%s", alias, op->name);
+
                        list = realloc(list, count + 2);
                        if (!list) {
                                warning("Failed to allocate plugin list for 
%s", name);
@@ -614,14 +615,10 @@ static int load_plugin(struct pevent *pevent, const char 
*path,
        void *handle;
        int ret;
 
-       plugin = malloc(strlen(path) + strlen(file) + 2);
-       if (!plugin)
+       ret = asprintf(&plugin, "%s/%s", path, file);
+       if (ret < 0)
                return -ENOMEM;
 
-       strcpy(plugin, path);
-       strcat(plugin, "/");
-       strcat(plugin, file);
-
        handle = dlopen(plugin, RTLD_NOW | RTLD_GLOBAL);
        if (!handle) {
                warning("cound not load plugin '%s'\n%s\n",
@@ -707,7 +704,7 @@ char *tracecmd_find_tracing_dir(void)
        char type[100];
        int use_debug = 0;
        FILE *fp;
-       
+
        if ((fp = fopen("/proc/mounts","r")) == NULL) {
                warning("Can't open /proc/mounts for read");
                return NULL;
@@ -749,16 +746,16 @@ char *tracecmd_find_tracing_dir(void)
        free(debug_str);
 
        if (use_debug) {
-               tracing_dir = malloc(strlen(fspath) + 9);
-               if (!tracing_dir)
-                       return NULL;
+               int ret;
 
-               sprintf(tracing_dir, "%s/tracing", fspath);
+               ret = asprintf(&tracing_dir, "%s/tracing", fspath);
+               if (ret < 0)
+                       return NULL;
        } else {
                tracing_dir = strdup(fspath);
                if (!tracing_dir)
                        return NULL;
-       }               
+       }
 
        return tracing_dir;
 }
@@ -774,16 +771,15 @@ const char *tracecmd_get_tracing_dir(void)
        return tracing_dir;
 }
 
+/* FIXME: append_file() is duplicated and could be consolidated */
 static char *append_file(const char *dir, const char *name)
 {
        char *file;
+       int ret;
 
-       file = malloc(strlen(dir) + strlen(name) + 2);
-       if (!file)
-               return NULL;
+       ret = asprintf(&file, "%s/%s", dir, name);
 
-       sprintf(file, "%s/%s", dir, name);
-       return file;
+       return ret < 0 ? NULL : file;
 }
 
 /**
@@ -1389,7 +1385,8 @@ int trace_util_load_plugins(struct pevent *pevent, const 
char *suffix,
 {
        char *home;
        char *path;
-        char *envdir;
+       char *envdir;
+       int ret;
 
        if (tracecmd_disable_plugins)
                return -EBUSY;
@@ -1412,14 +1409,10 @@ int trace_util_load_plugins(struct pevent *pevent, 
const char *suffix,
        if (!home)
                return -EINVAL;
 
-       path = malloc(strlen(home) + strlen(LOCAL_PLUGIN_DIR) + 2);
-       if (!path)
+       ret = asprintf(&path, "%s/%s", home, LOCAL_PLUGIN_DIR);
+       if (ret < 0)
                return -ENOMEM;
 
-       strcpy(path, home);
-       strcat(path, "/");
-       strcat(path, LOCAL_PLUGIN_DIR);
-
        trace_util_load_plugins_dir(pevent, suffix, path, load_plugin, data);
 
        free(path);
@@ -1506,15 +1499,12 @@ static int read_options(struct pevent *pevent, const 
char *path,
        int unload = 0;
        char *plugin;
        void *handle;
+       int ret;
 
-       plugin = malloc(strlen(path) + strlen(file) + 2);
-       if (!plugin)
+       ret = asprintf(&plugin, "%s/%s", path, file);
+       if (ret < 0)
                return -ENOMEM;
 
-       strcpy(plugin, path);
-       strcat(plugin, "/");
-       strcat(plugin, file);
-
        handle = dlopen(plugin, RTLD_NOW | RTLD_GLOBAL);
        if (!handle) {
                warning("cound not load plugin '%s'\n%s\n",
@@ -1603,6 +1593,7 @@ char *tracecmd_get_tracing_file(const char *name)
 {
        static const char *tracing;
        char *file;
+       int ret;
 
        if (!tracing) {
                tracing = tracecmd_find_tracing_dir();
@@ -1610,11 +1601,10 @@ char *tracecmd_get_tracing_file(const char *name)
                        return NULL;
        }
 
-       file = malloc(strlen(tracing) + strlen(name) + 2);
-       if (!file)
+       ret = asprintf(&file, "%s/%s", tracing, name);
+       if (ret < 0)
                return NULL;
 
-       sprintf(file, "%s/%s", tracing, name);
        return file;
 }
 
-- 
2.13.3

Reply via email to