root/tools/perf/util/probe-file.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * probe-file.c : operate ftrace k/uprobe events files
 *
 * Written by Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
 */
#include <errno.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <unistd.h>
#include <linux/zalloc.h>
#include "namespaces.h"
#include "event.h"
#include "strlist.h"
#include "strfilter.h"
#include "debug.h"
#include "build-id.h"
#include "dso.h"
#include "color.h"
#include "symbol.h"
#include "strbuf.h"
#include <api/fs/tracing_path.h>
#include <api/fs/fs.h>
#include "probe-event.h"
#include "probe-file.h"
#include "session.h"
#include "perf_regs.h"
#include "string2.h"
#include "dwarf-regs.h"

/* 4096 - 2 ('\n' + '\0') */
#define MAX_CMDLEN 4094

static bool print_common_warning(int err, bool readwrite)
{
        if (err == -EACCES)
                pr_warning("No permission to %s tracefs.\nPlease %s\n",
                           readwrite ? "write" : "read",
                           readwrite ? "run this command again with sudo." :
                                       "try 'sudo mount -o remount,mode=755 /sys/kernel/tracing/'");
        else
                return false;

        return true;
}

static bool print_configure_probe_event(int kerr, int uerr)
{
        const char *config, *file;

        if (kerr == -ENOENT && uerr == -ENOENT) {
                file = "{k,u}probe_events";
                config = "CONFIG_KPROBE_EVENTS=y and CONFIG_UPROBE_EVENTS=y";
        } else if (kerr == -ENOENT) {
                file = "kprobe_events";
                config = "CONFIG_KPROBE_EVENTS=y";
        } else if (uerr == -ENOENT) {
                file = "uprobe_events";
                config = "CONFIG_UPROBE_EVENTS=y";
        } else
                return false;

        if (!debugfs__configured() && !tracefs__configured())
                pr_warning("Debugfs or tracefs is not mounted\n"
                           "Please try 'sudo mount -t tracefs nodev /sys/kernel/tracing/'\n");
        else
                pr_warning("%s/%s does not exist.\nPlease rebuild kernel with %s.\n",
                           tracing_path_mount(), file, config);

        return true;
}

static void print_open_warning(int err, bool uprobe, bool readwrite)
{
        char sbuf[STRERR_BUFSIZE];

        if (print_common_warning(err, readwrite))
                return;

        if (print_configure_probe_event(uprobe ? 0 : err, uprobe ? err : 0))
                return;

        pr_warning("Failed to open %s/%cprobe_events: %s\n",
                   tracing_path_mount(), uprobe ? 'u' : 'k',
                   str_error_r(-err, sbuf, sizeof(sbuf)));
}

static void print_both_open_warning(int kerr, int uerr, bool readwrite)
{
        char sbuf[STRERR_BUFSIZE];

        if (kerr == uerr && print_common_warning(kerr, readwrite))
                return;

        if (print_configure_probe_event(kerr, uerr))
                return;

        if (kerr < 0)
                pr_warning("Failed to open %s/kprobe_events: %s.\n",
                           tracing_path_mount(),
                           str_error_r(-kerr, sbuf, sizeof(sbuf)));
        if (uerr < 0)
                pr_warning("Failed to open %s/uprobe_events: %s.\n",
                           tracing_path_mount(),
                           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, flag & PF_FL_RW);

        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, flag & PF_FL_RW);
                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);
                /* Skip if there is same name multi-probe event in the list */
                if (ret == -EEXIST)
                        ret = 0;
                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)) {
                        ret = strlist__add(plist, ent->s);
                        if (ret == -ENOMEM) {
                                pr_err("strlist__add failed with -ENOMEM\n");
                                goto out;
                        }
                        ret = 0;
                }
        }
out:
        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;
}

/* 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 */
                strlcpy(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__snprintf_build_id("/", sbuildid, sizeof(sbuildid));
        } else {
                nsinfo__mountns_enter(nsi, &nsc);
                ret = filename__snprintf_build_id(target, sbuildid, sizeof(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;
                        }
                        ret = strlist__add(entry->tevlist, buf);
                        if (ret == -ENOMEM) {
                                pr_err("strlist__add failed with -ENOMEM\n");
                                goto out;
                        }
                }
        }
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;
                ret = strlist__add(entry->tevlist, command);
                if (ret == -ENOMEM) {
                        pr_err("strlist__add failed with -ENOMEM\n");
                        goto out_err;
                }

                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[SDT_NOTE_IDX_LOC] :
                (unsigned long long)note->addr.a64[SDT_NOTE_IDX_LOC];
}

static unsigned long long sdt_note__get_ref_ctr_offset(struct sdt_note *note)
{
        return note->bit32 ?
                (unsigned long long)note->addr.a32[SDT_NOTE_IDX_REFCTR] :
                (unsigned long long)note->addr.a64[SDT_NOTE_IDX_REFCTR];
}

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 = perf_sdt_arg_parse_op(EM_HOST, 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;
        int i, args_count, err;
        unsigned long long ref_ctr_offset;
        char *arg;
        int arg_idx = 0;

        if (strbuf_init(&buf, 32) < 0)
                return NULL;

        err = strbuf_addf(&buf, "p:%s/%s %s:0x%llx",
                        sdtgrp, note->name, pathname,
                        sdt_note__get_addr(note));

        ref_ctr_offset = sdt_note__get_ref_ctr_offset(note);
        if (ref_ctr_offset && err >= 0)
                err = strbuf_addf(&buf, "(0x%llx)", ref_ctr_offset);

        if (err < 0)
                goto error;

        if (!note->args)
                goto out;

        if (note->args) {
                char **args = argv_split(note->args, &args_count);

                if (args == NULL)
                        goto error;

                for (i = 0; i < args_count; ) {
                        /*
                         * FIXUP: Arm64 ELF section '.note.stapsdt' uses string
                         * format "-4@[sp, NUM]" if a probe is to access data in
                         * the stack, e.g. below is an example for the SDT
                         * Arguments:
                         *
                         *   Arguments: -4@[sp, 12] -4@[sp, 8] -4@[sp, 4]
                         *
                         * Since the string introduces an extra space character
                         * in the middle of square brackets, the argument is
                         * divided into two items.  Fixup for this case, if an
                         * item contains sub string "[sp,", need to concatenate
                         * the two items.
                         */
                        if (strstr(args[i], "[sp,") && (i+1) < args_count) {
                                err = asprintf(&arg, "%s %s", args[i], args[i+1]);
                                i += 2;
                        } else {
                                err = asprintf(&arg, "%s", args[i]);
                                i += 1;
                        }

                        /* Failed to allocate memory */
                        if (err < 0) {
                                argv_free(args);
                                goto error;
                        }

                        if (synthesize_sdt_probe_arg(&buf, arg_idx, arg) < 0) {
                                free(arg);
                                argv_free(args);
                                goto error;
                        }

                        free(arg);
                        arg_idx++;
                }

                argv_free(args);
        }

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;
                }

                ret = strlist__add(entry->tevlist, buf);

                free(buf);
                entry = NULL;

                if (ret == -ENOMEM) {
                        pr_err("strlist__add failed with -ENOMEM\n");
                        break;
                }
        }
        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_UPROBE_REF_CTR,
        FTRACE_README_USER_ACCESS,
        FTRACE_README_MULTIPROBE_EVENT,
        FTRACE_README_IMMEDIATE_VALUE,
        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): *"),
        DEFINE_TYPE(FTRACE_README_UPROBE_REF_CTR, "*ref_ctr_offset*"),
        DEFINE_TYPE(FTRACE_README_USER_ACCESS, "*u]<offset>*"),
        DEFINE_TYPE(FTRACE_README_MULTIPROBE_EVENT, "*Create/append/*"),
        DEFINE_TYPE(FTRACE_README_IMMEDIATE_VALUE, "*\\imm-value,*"),
};

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);
}

bool uprobe_ref_ctr_is_supported(void)
{
        return scan_ftrace_readme(FTRACE_README_UPROBE_REF_CTR);
}

bool user_access_is_supported(void)
{
        return scan_ftrace_readme(FTRACE_README_USER_ACCESS);
}

bool multiprobe_event_is_supported(void)
{
        return scan_ftrace_readme(FTRACE_README_MULTIPROBE_EVENT);
}

bool immediate_value_is_supported(void)
{
        return scan_ftrace_readme(FTRACE_README_IMMEDIATE_VALUE);
}