text: /*
   * probe-file.c : operate ftrace k/uprobe events files
   *
   * Written by Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   */
  #include <errno.h>
  #include <fcntl.h>
  #include <sys/stat.h>
  #include <sys/types.h>
  #include <sys/uio.h>
  #include <unistd.h>
  #include "util.h"
  #include "event.h"
  #include "strlist.h"
  #include "strfilter.h"
  #include "debug.h"
  #include "cache.h"
  #include "color.h"
  #include "symbol.h"
  #include "thread.h"
  #include <api/fs/tracing_path.h>
  #include "probe-event.h"
  #include "probe-file.h"
  #include "session.h"
  #include "perf_regs.h"
  #include "string2.h"
  
  /* 4096 - 2 ('\n' + '\0') */
  #define MAX_CMDLEN 4094
  
  static void print_open_warning(int err, bool uprobe)
  {
  	char sbuf[STRERR_BUFSIZE];
  
  	if (err == -ENOENT) {
  		const char *config;
  
  		if (uprobe)
  			config = "CONFIG_UPROBE_EVENTS";
  		else
  			config = "CONFIG_KPROBE_EVENTS";
  
  		pr_warning("%cprobe_events file does not exist"
  			   " - please rebuild kernel with %s.\n",
  			   uprobe ? 'u' : 'k', config);
  	} else if (err == -ENOTSUP)
  		pr_warning("Tracefs or debugfs is not mounted.\n");
  	else
  		pr_warning("Failed to open %cprobe_events: %s\n",
  			   uprobe ? 'u' : 'k',
  			   str_error_r(-err, sbuf, sizeof(sbuf)));
  }
  
  static void print_both_open_warning(int kerr, int uerr)
  {
  	/* Both kprobes and uprobes are disabled, warn it. */
  	if (kerr == -ENOTSUP && uerr == -ENOTSUP)
  		pr_warning("Tracefs or debugfs is not mounted.\n");
  	else if (kerr == -ENOENT && uerr == -ENOENT)
  		pr_warning("Please rebuild kernel with CONFIG_KPROBE_EVENTS "
  			   "or/and CONFIG_UPROBE_EVENTS.\n");
  	else {
  		char sbuf[STRERR_BUFSIZE];
  		pr_warning("Failed to open kprobe events: %s.\n",
  			   str_error_r(-kerr, sbuf, sizeof(sbuf)));
  		pr_warning("Failed to open uprobe events: %s.\n",
  			   str_error_r(-uerr, sbuf, sizeof(sbuf)));
  	}
  }
  
  int open_trace_file(const char *trace_file, bool readwrite)
  {
  	char buf[PATH_MAX];
  	int ret;
  
  	ret = e_snprintf(buf, PATH_MAX, "%s/%s", tracing_path_mount(), trace_file);
  	if (ret >= 0) {
  		pr_debug("Opening %s write=%d\n", buf, readwrite);
  		if (readwrite && !probe_event_dry_run)
  			ret = open(buf, O_RDWR | O_APPEND, 0);
  		else
  			ret = open(buf, O_RDONLY, 0);
  
  		if (ret < 0)
  			ret = -errno;
  	}
  	return ret;
  }
  
  static int open_kprobe_events(bool readwrite)
  {
  	return open_trace_file("kprobe_events", readwrite);
  }
  
  static int open_uprobe_events(bool readwrite)
  {
  	return open_trace_file("uprobe_events", readwrite);
  }
  
  int probe_file__open(int flag)
  {
  	int fd;
  
  	if (flag & PF_FL_UPROBE)
  		fd = open_uprobe_events(flag & PF_FL_RW);
  	else
  		fd = open_kprobe_events(flag & PF_FL_RW);
  	if (fd < 0)
  		print_open_warning(fd, flag & PF_FL_UPROBE);
  
  	return fd;
  }
  
  int probe_file__open_both(int *kfd, int *ufd, int flag)
  {
  	if (!kfd || !ufd)
  		return -EINVAL;
  
  	*kfd = open_kprobe_events(flag & PF_FL_RW);
  	*ufd = open_uprobe_events(flag & PF_FL_RW);
  	if (*kfd < 0 && *ufd < 0) {
  		print_both_open_warning(*kfd, *ufd);
  		return *kfd;
  	}
  
  	return 0;
  }
  
  /* Get raw string list of current kprobe_events  or uprobe_events */
  struct strlist *probe_file__get_rawlist(int fd)
  {
  	int ret, idx, fddup;
  	FILE *fp;
  	char buf[MAX_CMDLEN];
  	char *p;
  	struct strlist *sl;
  
  	if (fd < 0)
  		return NULL;
  
  	sl = strlist__new(NULL, NULL);
  	if (sl == NULL)
  		return NULL;
  
  	fddup = dup(fd);
  	if (fddup < 0)
  		goto out_free_sl;
  
  	fp = fdopen(fddup, "r");
  	if (!fp)
  		goto out_close_fddup;
  
  	while (!feof(fp)) {
  		p = fgets(buf, MAX_CMDLEN, fp);
  		if (!p)
  			break;
  
  		idx = strlen(p) - 1;
  		if (p[idx] == '\n')
  			p[idx] = '\0';
  		ret = strlist__add(sl, buf);
  		if (ret < 0) {
  			pr_debug("strlist__add failed (%d)\n", ret);
  			goto out_close_fp;
  		}
  	}
  	fclose(fp);
  
  	return sl;
  
  out_close_fp:
  	fclose(fp);
  	goto out_free_sl;
  out_close_fddup:
  	close(fddup);
  out_free_sl:
  	strlist__delete(sl);
  	return NULL;
  }
  
  static struct strlist *__probe_file__get_namelist(int fd, bool include_group)
  {
  	char buf[128];
  	struct strlist *sl, *rawlist;
  	struct str_node *ent;
  	struct probe_trace_event tev;
  	int ret = 0;
  
  	memset(&tev, 0, sizeof(tev));
  	rawlist = probe_file__get_rawlist(fd);
  	if (!rawlist)
  		return NULL;
  	sl = strlist__new(NULL, NULL);
  	strlist__for_each_entry(ent, rawlist) {
  		ret = parse_probe_trace_command(ent->s, &tev);
  		if (ret < 0)
  			break;
  		if (include_group) {
  			ret = e_snprintf(buf, 128, "%s:%s", tev.group,
  					tev.event);
  			if (ret >= 0)
  				ret = strlist__add(sl, buf);
  		} else
  			ret = strlist__add(sl, tev.event);
  		clear_probe_trace_event(&tev);
  		if (ret < 0)
  			break;
  	}
  	strlist__delete(rawlist);
  
  	if (ret < 0) {
  		strlist__delete(sl);
  		return NULL;
  	}
  	return sl;
  }
  
  /* Get current perf-probe event names */
  struct strlist *probe_file__get_namelist(int fd)
  {
  	return __probe_file__get_namelist(fd, false);
  }
  
  int probe_file__add_event(int fd, struct probe_trace_event *tev)
  {
  	int ret = 0;
  	char *buf = synthesize_probe_trace_command(tev);
  	char sbuf[STRERR_BUFSIZE];
  
  	if (!buf) {
  		pr_debug("Failed to synthesize probe trace event.\n");
  		return -EINVAL;
  	}
  
  	pr_debug("Writing event: %s\n", buf);
  	if (!probe_event_dry_run) {
  		if (write(fd, buf, strlen(buf)) < (int)strlen(buf)) {
  			ret = -errno;
  			pr_warning("Failed to write event: %s\n",
  				   str_error_r(errno, sbuf, sizeof(sbuf)));
  		}
  	}
  	free(buf);
  
  	return ret;
  }
  
  static int __del_trace_probe_event(int fd, struct str_node *ent)
  {
  	char *p;
  	char buf[128];
  	int ret;
  
  	/* Convert from perf-probe event to trace-probe event */
  	ret = e_snprintf(buf, 128, "-:%s", ent->s);
  	if (ret < 0)
  		goto error;
  
  	p = strchr(buf + 2, ':');
  	if (!p) {
  		pr_debug("Internal error: %s should have ':' but not.\n",
  			 ent->s);
  		ret = -ENOTSUP;
  		goto error;
  	}
  	*p = '/';
  
  	pr_debug("Writing event: %s\n", buf);
  	ret = write(fd, buf, strlen(buf));
  	if (ret < 0) {
  		ret = -errno;
  		goto error;
  	}
  
  	return 0;
  error:
  	pr_warning("Failed to delete event: %s\n",
  		   str_error_r(-ret, buf, sizeof(buf)));
  	return ret;
  }
  
  int probe_file__get_events(int fd, struct strfilter *filter,
  			   struct strlist *plist)
  {
  	struct strlist *namelist;
  	struct str_node *ent;
  	const char *p;
  	int ret = -ENOENT;
  
  	if (!plist)
  		return -EINVAL;
  
  	namelist = __probe_file__get_namelist(fd, true);
  	if (!namelist)
  		return -ENOENT;
  
  	strlist__for_each_entry(ent, namelist) {
  		p = strchr(ent->s, ':');
  		if ((p && strfilter__compare(filter, p + 1)) ||
  		    strfilter__compare(filter, ent->s)) {
  			strlist__add(plist, ent->s);
  			ret = 0;
  		}
  	}
  	strlist__delete(namelist);
  
  	return ret;
  }
  
  int probe_file__del_strlist(int fd, struct strlist *namelist)
  {
  	int ret = 0;
  	struct str_node *ent;
  
  	strlist__for_each_entry(ent, namelist) {
  		ret = __del_trace_probe_event(fd, ent);
  		if (ret < 0)
  			break;
  	}
  	return ret;
  }
  
  int probe_file__del_events(int fd, struct strfilter *filter)
  {
  	struct strlist *namelist;
  	int ret;
  
  	namelist = strlist__new(NULL, NULL);
  	if (!namelist)
  		return -ENOMEM;
  
  	ret = probe_file__get_events(fd, filter, namelist);
  	if (ret < 0)
  		return ret;
  
  	ret = probe_file__del_strlist(fd, namelist);
  	strlist__delete(namelist);
  
  	return ret;
  }
  
  /* Caller must ensure to remove this entry from list */
  static void probe_cache_entry__delete(struct probe_cache_entry *entry)
  {
  	if (entry) {
  		BUG_ON(!list_empty(&entry->node));
  
  		strlist__delete(entry->tevlist);
  		clear_perf_probe_event(&entry->pev);
  		zfree(&entry->spev);
  		free(entry);
  	}
  }
  
  static struct probe_cache_entry *
  probe_cache_entry__new(struct perf_probe_event *pev)
  {
  	struct probe_cache_entry *entry = zalloc(sizeof(*entry));
  
  	if (entry) {
  		INIT_LIST_HEAD(&entry->node);
  		entry->tevlist = strlist__new(NULL, NULL);
  		if (!entry->tevlist)
  			zfree(&entry);
  		else if (pev) {
  			entry->spev = synthesize_perf_probe_command(pev);
  			if (!entry->spev ||
  			    perf_probe_event__copy(&entry->pev, pev) < 0) {
  				probe_cache_entry__delete(entry);
  				return NULL;
  			}
  		}
  	}
  
  	return entry;
  }
  
  int probe_cache_entry__get_event(struct probe_cache_entry *entry,
  				 struct probe_trace_event **tevs)
  {
  	struct probe_trace_event *tev;
  	struct str_node *node;
  	int ret, i;
  
  	ret = strlist__nr_entries(entry->tevlist);
  	if (ret > probe_conf.max_probes)
  		return -E2BIG;
  
  	*tevs = zalloc(ret * sizeof(*tev));
  	if (!*tevs)
  		return -ENOMEM;
  
  	i = 0;
  	strlist__for_each_entry(node, entry->tevlist) {
  		tev = &(*tevs)[i++];
  		ret = parse_probe_trace_command(node->s, tev);
  		if (ret < 0)
  			break;
  	}
  	return i;
  }
  
  /* For the kernel probe caches, pass target = NULL or DSO__NAME_KALLSYMS */
  static int probe_cache__open(struct probe_cache *pcache, const char *target,
  			     struct nsinfo *nsi)
  {
  	char cpath[PATH_MAX];
  	char sbuildid[SBUILD_ID_SIZE];
  	char *dir_name = NULL;
  	bool is_kallsyms = false;
  	int ret, fd;
  	struct nscookie nsc;
  
  	if (target && build_id_cache__cached(target)) {
  		/* This is a cached buildid */
  		strncpy(sbuildid, target, SBUILD_ID_SIZE);
  		dir_name = build_id_cache__linkname(sbuildid, NULL, 0);
  		goto found;
  	}
  
  	if (!target || !strcmp(target, DSO__NAME_KALLSYMS)) {
  		target = DSO__NAME_KALLSYMS;
  		is_kallsyms = true;
  		ret = sysfs__sprintf_build_id("/", sbuildid);
  	} else {
  		nsinfo__mountns_enter(nsi, &nsc);
  		ret = filename__sprintf_build_id(target, sbuildid);
  		nsinfo__mountns_exit(&nsc);
  	}
  
  	if (ret < 0) {
  		pr_debug("Failed to get build-id from %s.\n", target);
  		return ret;
  	}
  
  	/* If we have no buildid cache, make it */
  	if (!build_id_cache__cached(sbuildid)) {
  		ret = build_id_cache__add_s(sbuildid, target, nsi,
  					    is_kallsyms, NULL);
  		if (ret < 0) {
  			pr_debug("Failed to add build-id cache: %s\n", target);
  			return ret;
  		}
  	}
  
  	dir_name = build_id_cache__cachedir(sbuildid, target, nsi, is_kallsyms,
  					    false);
  found:
  	if (!dir_name) {
  		pr_debug("Failed to get cache from %s\n", target);
  		return -ENOMEM;
  	}
  
  	snprintf(cpath, PATH_MAX, "%s/probes", dir_name);
  	fd = open(cpath, O_CREAT | O_RDWR, 0644);
  	if (fd < 0)
  		pr_debug("Failed to open cache(%d): %s\n", fd, cpath);
  	free(dir_name);
  	pcache->fd = fd;
  
  	return fd;
  }
  
  static int probe_cache__load(struct probe_cache *pcache)
  {
  	struct probe_cache_entry *entry = NULL;
  	char buf[MAX_CMDLEN], *p;
  	int ret = 0, fddup;
  	FILE *fp;
  
  	fddup = dup(pcache->fd);
  	if (fddup < 0)
  		return -errno;
  	fp = fdopen(fddup, "r");
  	if (!fp) {
  		close(fddup);
  		return -EINVAL;
  	}
  
  	while (!feof(fp)) {
  		if (!fgets(buf, MAX_CMDLEN, fp))
  			break;
  		p = strchr(buf, '\n');
  		if (p)
  			*p = '\0';
  		/* #perf_probe_event or %sdt_event */
  		if (buf[0] == '#' || buf[0] == '%') {
  			entry = probe_cache_entry__new(NULL);
  			if (!entry) {
  				ret = -ENOMEM;
  				goto out;
  			}
  			if (buf[0] == '%')
  				entry->sdt = true;
  			entry->spev = strdup(buf + 1);
  			if (entry->spev)
  				ret = parse_perf_probe_command(buf + 1,
  								&entry->pev);
  			else
  				ret = -ENOMEM;
  			if (ret < 0) {
  				probe_cache_entry__delete(entry);
  				goto out;
  			}
  			list_add_tail(&entry->node, &pcache->entries);
  		} else {	/* trace_probe_event */
  			if (!entry) {
  				ret = -EINVAL;
  				goto out;
  			}
  			strlist__add(entry->tevlist, buf);
  		}
  	}
  out:
  	fclose(fp);
  	return ret;
  }
  
  static struct probe_cache *probe_cache__alloc(void)
  {
  	struct probe_cache *pcache = zalloc(sizeof(*pcache));
  
  	if (pcache) {
  		INIT_LIST_HEAD(&pcache->entries);
  		pcache->fd = -EINVAL;
  	}
  	return pcache;
  }
  
  void probe_cache__purge(struct probe_cache *pcache)
  {
  	struct probe_cache_entry *entry, *n;
  
  	list_for_each_entry_safe(entry, n, &pcache->entries, node) {
  		list_del_init(&entry->node);
  		probe_cache_entry__delete(entry);
  	}
  }
  
  void probe_cache__delete(struct probe_cache *pcache)
  {
  	if (!pcache)
  		return;
  
  	probe_cache__purge(pcache);
  	if (pcache->fd > 0)
  		close(pcache->fd);
  	free(pcache);
  }
  
  struct probe_cache *probe_cache__new(const char *target, struct nsinfo *nsi)
  {
  	struct probe_cache *pcache = probe_cache__alloc();
  	int ret;
  
  	if (!pcache)
  		return NULL;
  
  	ret = probe_cache__open(pcache, target, nsi);
  	if (ret < 0) {
  		pr_debug("Cache open error: %d\n", ret);
  		goto out_err;
  	}
  
  	ret = probe_cache__load(pcache);
  	if (ret < 0) {
  		pr_debug("Cache read error: %d\n", ret);
  		goto out_err;
  	}
  
  	return pcache;
  
  out_err:
  	probe_cache__delete(pcache);
  	return NULL;
  }
  
  static bool streql(const char *a, const char *b)
  {
  	if (a == b)
  		return true;
  
  	if (!a || !b)
  		return false;
  
  	return !strcmp(a, b);
  }
  
  struct probe_cache_entry *
  probe_cache__find(struct probe_cache *pcache, struct perf_probe_event *pev)
  {
  	struct probe_cache_entry *entry = NULL;
  	char *cmd = synthesize_perf_probe_command(pev);
  
  	if (!cmd)
  		return NULL;
  
  	for_each_probe_cache_entry(entry, pcache) {
  		if (pev->sdt) {
  			if (entry->pev.event &&
  			    streql(entry->pev.event, pev->event) &&
  			    (!pev->group ||
  			     streql(entry->pev.group, pev->group)))
  				goto found;
  
  			continue;
  		}
  		/* Hit if same event name or same command-string */
  		if ((pev->event &&
  		     (streql(entry->pev.group, pev->group) &&
  		      streql(entry->pev.event, pev->event))) ||
  		    (!strcmp(entry->spev, cmd)))
  			goto found;
  	}
  	entry = NULL;
  
  found:
  	free(cmd);
  	return entry;
  }
  
  struct probe_cache_entry *
  probe_cache__find_by_name(struct probe_cache *pcache,
  			  const char *group, const char *event)
  {
  	struct probe_cache_entry *entry = NULL;
  
  	for_each_probe_cache_entry(entry, pcache) {
  		/* Hit if same event name or same command-string */
  		if (streql(entry->pev.group, group) &&
  		    streql(entry->pev.event, event))
  			goto found;
  	}
  	entry = NULL;
  
  found:
  	return entry;
  }
  
  int probe_cache__add_entry(struct probe_cache *pcache,
  			   struct perf_probe_event *pev,
  			   struct probe_trace_event *tevs, int ntevs)
  {
  	struct probe_cache_entry *entry = NULL;
  	char *command;
  	int i, ret = 0;
  
  	if (!pcache || !pev || !tevs || ntevs <= 0) {
  		ret = -EINVAL;
  		goto out_err;
  	}
  
  	/* Remove old cache entry */
  	entry = probe_cache__find(pcache, pev);
  	if (entry) {
  		list_del_init(&entry->node);
  		probe_cache_entry__delete(entry);
  	}
  
  	ret = -ENOMEM;
  	entry = probe_cache_entry__new(pev);
  	if (!entry)
  		goto out_err;
  
  	for (i = 0; i < ntevs; i++) {
  		if (!tevs[i].point.symbol)
  			continue;
  
  		command = synthesize_probe_trace_command(&tevs[i]);
  		if (!command)
  			goto out_err;
  		strlist__add(entry->tevlist, command);
  		free(command);
  	}
  	list_add_tail(&entry->node, &pcache->entries);
  	pr_debug("Added probe cache: %d\n", ntevs);
  	return 0;
  
  out_err:
  	pr_debug("Failed to add probe caches\n");
  	probe_cache_entry__delete(entry);
  	return ret;
  }
  
  #ifdef HAVE_GELF_GETNOTE_SUPPORT
  static unsigned long long sdt_note__get_addr(struct sdt_note *note)
  {
  	return note->bit32 ? (unsigned long long)note->addr.a32[0]
  		 : (unsigned long long)note->addr.a64[0];
  }
  
  static const char * const type_to_suffix[] = {
  	":s64", "", "", "", ":s32", "", ":s16", ":s8",
  	"", ":u8", ":u16", "", ":u32", "", "", "", ":u64"
  };
  
  /*
   * Isolate the string number and convert it into a decimal value;
   * this will be an index to get suffix of the uprobe name (defining
   * the type)
   */
  static int sdt_arg_parse_size(char *n_ptr, const char **suffix)
  {
  	long type_idx;
  
  	type_idx = strtol(n_ptr, NULL, 10);
  	if (type_idx < -8 || type_idx > 8) {
  		pr_debug4("Failed to get a valid sdt type\n");
  		return -1;
  	}
  
  	*suffix = type_to_suffix[type_idx + 8];
  	return 0;
  }
  
  static int synthesize_sdt_probe_arg(struct strbuf *buf, int i, const char *arg)
  {
  	char *op, *desc = strdup(arg), *new_op = NULL;
  	const char *suffix = "";
  	int ret = -1;
  
  	if (desc == NULL) {
  		pr_debug4("Allocation error\n");
  		return ret;
  	}
  
  	/*
  	 * Argument is in N@OP format. N is size of the argument and OP is
  	 * the actual assembly operand. N can be omitted; in that case
  	 * argument is just OP(without @).
  	 */
  	op = strchr(desc, '@');
  	if (op) {
  		op[0] = '\0';
  		op++;
  
  		if (sdt_arg_parse_size(desc, &suffix))
  			goto error;
  	} else {
  		op = desc;
  	}
  
  	ret = arch_sdt_arg_parse_op(op, &new_op);
  
  	if (ret < 0)
  		goto error;
  
  	if (ret == SDT_ARG_VALID) {
  		ret = strbuf_addf(buf, " arg%d=%s%s", i + 1, new_op, suffix);
  		if (ret < 0)
  			goto error;
  	}
  
  	ret = 0;
  error:
  	free(desc);
  	free(new_op);
  	return ret;
  }
  
  static char *synthesize_sdt_probe_command(struct sdt_note *note,
  					const char *pathname,
  					const char *sdtgrp)
  {
  	struct strbuf buf;
  	char *ret = NULL, **args;
  	int i, args_count;
  
  	if (strbuf_init(&buf, 32) < 0)
  		return NULL;
  
  	if (strbuf_addf(&buf, "p:%s/%s %s:0x%llx",
  				sdtgrp, note->name, pathname,
  				sdt_note__get_addr(note)) < 0)
  		goto error;
  
  	if (!note->args)
  		goto out;
  
  	if (note->args) {
  		args = argv_split(note->args, &args_count);
  
  		for (i = 0; i < args_count; ++i) {
  			if (synthesize_sdt_probe_arg(&buf, i, args[i]) < 0)
  				goto error;
  		}
  	}
  
  out:
  	ret = strbuf_detach(&buf, NULL);
  error:
  	strbuf_release(&buf);
  	return ret;
  }
  
  int probe_cache__scan_sdt(struct probe_cache *pcache, const char *pathname)
  {
  	struct probe_cache_entry *entry = NULL;
  	struct list_head sdtlist;
  	struct sdt_note *note;
  	char *buf;
  	char sdtgrp[64];
  	int ret;
  
  	INIT_LIST_HEAD(&sdtlist);
  	ret = get_sdt_note_list(&sdtlist, pathname);
  	if (ret < 0) {
  		pr_debug4("Failed to get sdt note: %d\n", ret);
  		return ret;
  	}
  	list_for_each_entry(note, &sdtlist, note_list) {
  		ret = snprintf(sdtgrp, 64, "sdt_%s", note->provider);
  		if (ret < 0)
  			break;
  		/* Try to find same-name entry */
  		entry = probe_cache__find_by_name(pcache, sdtgrp, note->name);
  		if (!entry) {
  			entry = probe_cache_entry__new(NULL);
  			if (!entry) {
  				ret = -ENOMEM;
  				break;
  			}
  			entry->sdt = true;
  			ret = asprintf(&entry->spev, "%s:%s=%s", sdtgrp,
  					note->name, note->name);
  			if (ret < 0)
  				break;
  			entry->pev.event = strdup(note->name);
  			entry->pev.group = strdup(sdtgrp);
  			list_add_tail(&entry->node, &pcache->entries);
  		}
  		buf = synthesize_sdt_probe_command(note, pathname, sdtgrp);
  		if (!buf) {
  			ret = -ENOMEM;
  			break;
  		}
  
  		strlist__add(entry->tevlist, buf);
  		free(buf);
  		entry = NULL;
  	}
  	if (entry) {
  		list_del_init(&entry->node);
  		probe_cache_entry__delete(entry);
  	}
  	cleanup_sdt_note_list(&sdtlist);
  	return ret;
  }
  #endif
  
  static int probe_cache_entry__write(struct probe_cache_entry *entry, int fd)
  {
  	struct str_node *snode;
  	struct stat st;
  	struct iovec iov[3];
  	const char *prefix = entry->sdt ? "%" : "#";
  	int ret;
  	/* Save stat for rollback */
  	ret = fstat(fd, &st);
  	if (ret < 0)
  		return ret;
  
  	pr_debug("Writing cache: %s%s\n", prefix, entry->spev);
  	iov[0].iov_base = (void *)prefix; iov[0].iov_len = 1;
  	iov[1].iov_base = entry->spev; iov[1].iov_len = strlen(entry->spev);
  	iov[2].iov_base = (void *)"\n"; iov[2].iov_len = 1;
  	ret = writev(fd, iov, 3);
  	if (ret < (int)iov[1].iov_len + 2)
  		goto rollback;
  
  	strlist__for_each_entry(snode, entry->tevlist) {
  		iov[0].iov_base = (void *)snode->s;
  		iov[0].iov_len = strlen(snode->s);
  		iov[1].iov_base = (void *)"\n"; iov[1].iov_len = 1;
  		ret = writev(fd, iov, 2);
  		if (ret < (int)iov[0].iov_len + 1)
  			goto rollback;
  	}
  	return 0;
  
  rollback:
  	/* Rollback to avoid cache file corruption */
  	if (ret > 0)
  		ret = -1;
  	if (ftruncate(fd, st.st_size) < 0)
  		ret = -2;
  
  	return ret;
  }
  
  int probe_cache__commit(struct probe_cache *pcache)
  {
  	struct probe_cache_entry *entry;
  	int ret = 0;
  
  	/* TBD: if we do not update existing entries, skip it */
  	ret = lseek(pcache->fd, 0, SEEK_SET);
  	if (ret < 0)
  		goto out;
  
  	ret = ftruncate(pcache->fd, 0);
  	if (ret < 0)
  		goto out;
  
  	for_each_probe_cache_entry(entry, pcache) {
  		ret = probe_cache_entry__write(entry, pcache->fd);
  		pr_debug("Cache committed: %d\n", ret);
  		if (ret < 0)
  			break;
  	}
  out:
  	return ret;
  }
  
  static bool probe_cache_entry__compare(struct probe_cache_entry *entry,
  				       struct strfilter *filter)
  {
  	char buf[128], *ptr = entry->spev;
  
  	if (entry->pev.event) {
  		snprintf(buf, 128, "%s:%s", entry->pev.group, entry->pev.event);
  		ptr = buf;
  	}
  	return strfilter__compare(filter, ptr);
  }
  
  int probe_cache__filter_purge(struct probe_cache *pcache,
  			      struct strfilter *filter)
  {
  	struct probe_cache_entry *entry, *tmp;
  
  	list_for_each_entry_safe(entry, tmp, &pcache->entries, node) {
  		if (probe_cache_entry__compare(entry, filter)) {
  			pr_info("Removed cached event: %s\n", entry->spev);
  			list_del_init(&entry->node);
  			probe_cache_entry__delete(entry);
  		}
  	}
  	return 0;
  }
  
  static int probe_cache__show_entries(struct probe_cache *pcache,
  				     struct strfilter *filter)
  {
  	struct probe_cache_entry *entry;
  
  	for_each_probe_cache_entry(entry, pcache) {
  		if (probe_cache_entry__compare(entry, filter))
  			printf("%s\n", entry->spev);
  	}
  	return 0;
  }
  
  /* Show all cached probes */
  int probe_cache__show_all_caches(struct strfilter *filter)
  {
  	struct probe_cache *pcache;
  	struct strlist *bidlist;
  	struct str_node *nd;
  	char *buf = strfilter__string(filter);
  
  	pr_debug("list cache with filter: %s\n", buf);
  	free(buf);
  
  	bidlist = build_id_cache__list_all(true);
  	if (!bidlist) {
  		pr_debug("Failed to get buildids: %d\n", errno);
  		return -EINVAL;
  	}
  	strlist__for_each_entry(nd, bidlist) {
  		pcache = probe_cache__new(nd->s, NULL);
  		if (!pcache)
  			continue;
  		if (!list_empty(&pcache->entries)) {
  			buf = build_id_cache__origname(nd->s);
  			printf("%s (%s):\n", buf, nd->s);
  			free(buf);
  			probe_cache__show_entries(pcache, filter);
  		}
  		probe_cache__delete(pcache);
  	}
  	strlist__delete(bidlist);
  
  	return 0;
  }
  
  enum ftrace_readme {
  	FTRACE_README_PROBE_TYPE_X = 0,
  	FTRACE_README_KRETPROBE_OFFSET,
  	FTRACE_README_END,
  };
  
  static struct {
  	const char *pattern;
  	bool avail;
  } ftrace_readme_table[] = {
  #define DEFINE_TYPE(idx, pat)			\
  	[idx] = {.pattern = pat, .avail = false}
  	DEFINE_TYPE(FTRACE_README_PROBE_TYPE_X, "*type: * x8/16/32/64,*"),
  	DEFINE_TYPE(FTRACE_README_KRETPROBE_OFFSET, "*place (kretprobe): *"),
  };
  
  static bool scan_ftrace_readme(enum ftrace_readme type)
  {
  	int fd;
  	FILE *fp;
  	char *buf = NULL;
  	size_t len = 0;
  	bool ret = false;
  	static bool scanned = false;
  
  	if (scanned)
  		goto result;
  
  	fd = open_trace_file("README", false);
  	if (fd < 0)
  		return ret;
  
  	fp = fdopen(fd, "r");
  	if (!fp) {
  		close(fd);
  		return ret;
  	}
  
  	while (getline(&buf, &len, fp) > 0)
  		for (enum ftrace_readme i = 0; i < FTRACE_README_END; i++)
  			if (!ftrace_readme_table[i].avail)
  				ftrace_readme_table[i].avail =
  					strglobmatch(buf, ftrace_readme_table[i].pattern);
  	scanned = true;
  
  	fclose(fp);
  	free(buf);
  
  result:
  	if (type >= FTRACE_README_END)
  		return false;
  
  	return ftrace_readme_table[type].avail;
  }
  
  bool probe_type_is_available(enum probe_type type)
  {
  	if (type >= PROBE_TYPE_END)
  		return false;
  	else if (type == PROBE_TYPE_X)
  		return scan_ftrace_readme(FTRACE_README_PROBE_TYPE_X);
  
  	return true;
  }
  
  bool kretprobe_offset_is_supported(void)
  {
  	return scan_ftrace_readme(FTRACE_README_KRETPROBE_OFFSET);
  }
  