Cleanup: sessiond modprobe.c: coding style
[lttng-tools.git] / src / bin / lttng-sessiond / modprobe.c
index 968b2650e05c9685fc04b3e56e29bb5fb87cd1ae..b5b9d8cb793c2d6bbffc156d0ea8f6d314a4b0c7 100644 (file)
@@ -17,6 +17,8 @@
  */
 
 #define _GNU_SOURCE
+#define _LGPL_SOURCE
+#include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/wait.h>
@@ -95,9 +97,10 @@ struct kern_modules_param kern_modules_probes_default[] = {
 /* dynamic probe modules list */
 static struct kern_modules_param *probes;
 static int nr_probes;
+static int probes_capacity;
 
-void modprobe_remove_lttng(const struct kern_modules_param *modules,
-                          int entries, int required)
+static void modprobe_remove_lttng(const struct kern_modules_param *modules,
+               int entries, int required)
 {
        int ret = 0, i;
        char modprobe[256];
@@ -122,8 +125,6 @@ void modprobe_remove_lttng(const struct kern_modules_param *modules,
                        DBG("Modprobe removal successful %s",
                                        modules[i].name);
                }
-               if (probes)
-                       free(probes[i].name);
        }
 }
 
@@ -145,14 +146,18 @@ void modprobe_remove_lttng_control(void)
  */
 void modprobe_remove_lttng_data(void)
 {
+       int i;
+
        if (probes) {
                modprobe_remove_lttng(probes, nr_probes, LTTNG_MOD_OPTIONAL);
+
+               for (i = 0; i < nr_probes; ++i) {
+                       free(probes[i].name);
+               }
+
                free(probes);
                probes = NULL;
-       } else
-               modprobe_remove_lttng(kern_modules_probes_default,
-                                     ARRAY_SIZE(kern_modules_probes_default),
-                                     LTTNG_MOD_OPTIONAL);
+       }
 }
 
 /*
@@ -205,8 +210,16 @@ static int modprobe_lttng(struct kern_modules_param *modules,
 
                ret = kmod_module_probe_insert_module(mod, KMOD_PROBE_IGNORE_LOADED,
                                NULL, NULL, NULL, NULL);
-               if (required && ret < 0) {
-                       ERR("Unable to load module %s", modules[i].name);
+               if (ret < 0) {
+                       if (required) {
+                               ERR("Unable to load required module %s",
+                                               modules[i].name);
+                               goto error;
+                       } else {
+                               DBG("Unable to load optional module %s; continuing",
+                                               modules[i].name);
+                               ret = 0;
+                       }
                } else {
                        DBG("Modprobe successfully %s", modules[i].name);
                }
@@ -241,10 +254,25 @@ static int modprobe_lttng(struct kern_modules_param *modules,
                modprobe[sizeof(modprobe) - 1] = '\0';
                ret = system(modprobe);
                if (ret == -1) {
-                       ERR("Unable to launch modprobe for module %s",
-                                       modules[i].name);
-               } else if (required && WEXITSTATUS(ret) != 0) {
-                       ERR("Unable to load module %s", modules[i].name);
+                       if (required) {
+                               ERR("Unable to launch modprobe for required module %s",
+                                               modules[i].name);
+                               goto error;
+                       } else {
+                               DBG("Unable to launch modprobe for optional module %s; continuing",
+                                               modules[i].name);
+                               ret = 0;
+                       }
+               } else if (WEXITSTATUS(ret) != 0) {
+                       if (required) {
+                               ERR("Unable to load required module %s",
+                                               modules[i].name);
+                               goto error;
+                       } else {
+                               DBG("Unable to load optional module %s; continuing",
+                                               modules[i].name);
+                               ret = 0;
+                       }
                } else {
                        DBG("Modprobe successfully %s", modules[i].name);
                }
@@ -274,72 +302,180 @@ int modprobe_lttng_control(void)
        return ret;
 }
 
-/*
- * Load data kernel module(s).
+/**
+ * Grow global list of probes (double capacity or set it to 1 if
+ * currently 0 and copy existing data).
  */
-int modprobe_lttng_data(void)
+static int grow_probes(void)
 {
-       int i, ret;
-       int entries = ARRAY_SIZE(kern_modules_probes_default);
-       char *list, *next;
+       int i;
+       struct kern_modules_param *tmp_probes;
 
-       /*
-        * First take command line option, if not available take environment
-        * variable.
-        */
-       if (kmod_probes_list) {
-               list = kmod_probes_list;
-       } else {
-               list = utils_get_kmod_probes_list();
-       }
-       /* The default is to load ALL probes */
-       if (!list) {
-               return modprobe_lttng(kern_modules_probes_default, entries,
-                               LTTNG_MOD_OPTIONAL);
+       /* Initialize capacity to 1 if 0. */
+       if (probes_capacity == 0) {
+               probes = zmalloc(sizeof(*probes));
+               if (!probes) {
+                       PERROR("malloc probe list");
+                       return -ENOMEM;
+               }
+
+               probes_capacity = 1;
+               return 0;
        }
 
-       /*
-        * A probe list is available, so use it.
-        * The number of probes is limited by the number of probes in the
-        * default list.
-        */
-       probes = zmalloc(sizeof(struct kern_modules_param *) * entries);
-       if (!probes) {
+       /* Double size. */
+       probes_capacity *= 2;
+
+       tmp_probes = zmalloc(sizeof(*tmp_probes) * probes_capacity);
+       if (!tmp_probes) {
                PERROR("malloc probe list");
                return -ENOMEM;
        }
 
-       for (i = 0; i < entries; i++) {
+       for (i = 0; i < nr_probes; ++i) {
+               /* Move name pointer. */
+               tmp_probes[i].name = probes[i].name;
+       }
+
+       /* Replace probes with larger copy. */
+       free(probes);
+       probes = tmp_probes;
+
+       return 0;
+}
+
+/*
+ * Appends a comma-separated list of probes to the global list
+ * of probes.
+ */
+static int append_list_to_probes(const char *list)
+{
+       char *next;
+       int index = nr_probes, ret;
+       char *tmp_list;
+
+       assert(list);
+
+       tmp_list = strdup(list);
+       if (!tmp_list) {
+               PERROR("strdup temp list");
+               return -ENOMEM;
+       }
+
+       for (;;) {
                size_t name_len;
+               struct kern_modules_param *cur_mod;
 
-               next = strtok(list, ",");
+               next = strtok(tmp_list, ",");
                if (!next) {
-                       goto out;
+                       break;
                }
-               list = NULL;
+               tmp_list = NULL;
 
                /* filter leading spaces */
                while (*next == ' ') {
                        next++;
                }
 
+               if (probes_capacity <= nr_probes) {
+                       ret = grow_probes();
+                       if (ret) {
+                               return ret;
+                       }
+               }
+
                /* Length 13 is "lttng-probe-" + \0 */
                name_len = strlen(next) + 13;
 
-               probes[i].name = zmalloc(name_len);
-               if (!probes[i].name) {
+               cur_mod = &probes[index];
+               cur_mod->name = zmalloc(name_len);
+               if (!cur_mod->name) {
                        PERROR("malloc probe list");
                        return -ENOMEM;
                }
 
-               ret = snprintf(probes[i].name, name_len, "lttng-probe-%s", next);
+               ret = snprintf(cur_mod->name, name_len, "lttng-probe-%s", next);
                if (ret < 0) {
                        PERROR("snprintf modprobe name");
-                       goto out;
+                       return -ENOMEM;
                }
+
+               cur_mod++;
+               nr_probes++;
+       }
+
+       free(tmp_list);
+
+       return 0;
+}
+
+/*
+ * Load data kernel module(s).
+ */
+int modprobe_lttng_data(void)
+{
+       int ret, i;
+       char *list;
+
+       /*
+        * Base probes: either from command line option, environment
+        * variable or default list.
+        */
+       if (kmod_probes_list) {
+               list = kmod_probes_list;
+       } else {
+               list = utils_get_kmod_probes_list();
        }
 
-out:
-       nr_probes = i;
+       if (list) {
+               /* User-specified probes. */
+               ret = append_list_to_probes(list);
+
+               if (ret) {
+                       return ret;
+               }
+       } else {
+               /* Default probes. */
+               int def_len = ARRAY_SIZE(kern_modules_probes_default);
+
+               probes = zmalloc(sizeof(*probes) * def_len);
+               if (!probes) {
+                       PERROR("malloc probe list");
+                       return -ENOMEM;
+               }
+
+               nr_probes = probes_capacity = def_len;
+
+               for (i = 0; i < def_len; ++i) {
+                       char* name = strdup(kern_modules_probes_default[i].name);
+
+                       if (!name) {
+                               PERROR("strdup probe item");
+                               return -ENOMEM;
+                       }
+
+                       probes[i].name = name;
+               }
+       }
+
+       /*
+        * Extra modules? Append them to current probes list.
+        */
+       if (kmod_extra_probes_list) {
+               list = kmod_extra_probes_list;
+       } else {
+               list = utils_get_extra_kmod_probes_list();
+       }
+
+       if (list) {
+               ret = append_list_to_probes(list);
+               if (ret) {
+                       return ret;
+               }
+       }
+
+       /*
+        * Load probes modules now.
+        */
        return modprobe_lttng(probes, nr_probes, LTTNG_MOD_OPTIONAL);
 }
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