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-rw-r--r--tools/lib/api/fd/array.c23
-rw-r--r--tools/lib/api/fd/array.h16
-rw-r--r--tools/lib/api/fs/Build1
-rw-r--r--tools/lib/api/fs/cgroup.c67
-rw-r--r--tools/lib/api/fs/fs.c17
-rw-r--r--tools/lib/api/fs/fs.h14
-rw-r--r--tools/lib/api/io.h115
7 files changed, 240 insertions, 13 deletions
diff --git a/tools/lib/api/fd/array.c b/tools/lib/api/fd/array.c
index 58d44d5eee31..5e6cb9debe37 100644
--- a/tools/lib/api/fd/array.c
+++ b/tools/lib/api/fd/array.c
@@ -8,6 +8,7 @@
#include <poll.h>
#include <stdlib.h>
#include <unistd.h>
+#include <string.h>
void fdarray__init(struct fdarray *fda, int nr_autogrow)
{
@@ -19,7 +20,7 @@ void fdarray__init(struct fdarray *fda, int nr_autogrow)
int fdarray__grow(struct fdarray *fda, int nr)
{
- void *priv;
+ struct priv *priv;
int nr_alloc = fda->nr_alloc + nr;
size_t psize = sizeof(fda->priv[0]) * nr_alloc;
size_t size = sizeof(struct pollfd) * nr_alloc;
@@ -34,6 +35,9 @@ int fdarray__grow(struct fdarray *fda, int nr)
return -ENOMEM;
}
+ memset(&entries[fda->nr_alloc], 0, sizeof(struct pollfd) * nr);
+ memset(&priv[fda->nr_alloc], 0, sizeof(fda->priv[0]) * nr);
+
fda->nr_alloc = nr_alloc;
fda->entries = entries;
fda->priv = priv;
@@ -69,7 +73,7 @@ void fdarray__delete(struct fdarray *fda)
free(fda);
}
-int fdarray__add(struct fdarray *fda, int fd, short revents)
+int fdarray__add(struct fdarray *fda, int fd, short revents, enum fdarray_flags flags)
{
int pos = fda->nr;
@@ -79,6 +83,7 @@ int fdarray__add(struct fdarray *fda, int fd, short revents)
fda->entries[fda->nr].fd = fd;
fda->entries[fda->nr].events = revents;
+ fda->priv[fda->nr].flags = flags;
fda->nr++;
return pos;
}
@@ -93,22 +98,22 @@ int fdarray__filter(struct fdarray *fda, short revents,
return 0;
for (fd = 0; fd < fda->nr; ++fd) {
+ if (!fda->entries[fd].events)
+ continue;
+
if (fda->entries[fd].revents & revents) {
if (entry_destructor)
entry_destructor(fda, fd, arg);
+ fda->entries[fd].revents = fda->entries[fd].events = 0;
continue;
}
- if (fd != nr) {
- fda->entries[nr] = fda->entries[fd];
- fda->priv[nr] = fda->priv[fd];
- }
-
- ++nr;
+ if (!(fda->priv[fd].flags & fdarray_flag__nonfilterable))
+ ++nr;
}
- return fda->nr = nr;
+ return nr;
}
int fdarray__poll(struct fdarray *fda, int timeout)
diff --git a/tools/lib/api/fd/array.h b/tools/lib/api/fd/array.h
index b39557d1a88f..7fcf21a33c0c 100644
--- a/tools/lib/api/fd/array.h
+++ b/tools/lib/api/fd/array.h
@@ -21,19 +21,27 @@ struct fdarray {
int nr_alloc;
int nr_autogrow;
struct pollfd *entries;
- union {
- int idx;
- void *ptr;
+ struct priv {
+ union {
+ int idx;
+ void *ptr;
+ };
+ unsigned int flags;
} *priv;
};
+enum fdarray_flags {
+ fdarray_flag__default = 0x00000000,
+ fdarray_flag__nonfilterable = 0x00000001
+};
+
void fdarray__init(struct fdarray *fda, int nr_autogrow);
void fdarray__exit(struct fdarray *fda);
struct fdarray *fdarray__new(int nr_alloc, int nr_autogrow);
void fdarray__delete(struct fdarray *fda);
-int fdarray__add(struct fdarray *fda, int fd, short revents);
+int fdarray__add(struct fdarray *fda, int fd, short revents, enum fdarray_flags flags);
int fdarray__poll(struct fdarray *fda, int timeout);
int fdarray__filter(struct fdarray *fda, short revents,
void (*entry_destructor)(struct fdarray *fda, int fd, void *arg),
diff --git a/tools/lib/api/fs/Build b/tools/lib/api/fs/Build
index f4ed9629ae85..0f75b28654de 100644
--- a/tools/lib/api/fs/Build
+++ b/tools/lib/api/fs/Build
@@ -1,2 +1,3 @@
libapi-y += fs.o
libapi-y += tracing_path.o
+libapi-y += cgroup.o
diff --git a/tools/lib/api/fs/cgroup.c b/tools/lib/api/fs/cgroup.c
new file mode 100644
index 000000000000..889a6eb4aaca
--- /dev/null
+++ b/tools/lib/api/fs/cgroup.c
@@ -0,0 +1,67 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/stringify.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "fs.h"
+
+int cgroupfs_find_mountpoint(char *buf, size_t maxlen, const char *subsys)
+{
+ FILE *fp;
+ char mountpoint[PATH_MAX + 1], tokens[PATH_MAX + 1], type[PATH_MAX + 1];
+ char path_v1[PATH_MAX + 1], path_v2[PATH_MAX + 2], *path;
+ char *token, *saved_ptr = NULL;
+
+ fp = fopen("/proc/mounts", "r");
+ if (!fp)
+ return -1;
+
+ /*
+ * in order to handle split hierarchy, we need to scan /proc/mounts
+ * and inspect every cgroupfs mount point to find one that has
+ * perf_event subsystem
+ */
+ path_v1[0] = '\0';
+ path_v2[0] = '\0';
+
+ while (fscanf(fp, "%*s %"__stringify(PATH_MAX)"s %"__stringify(PATH_MAX)"s %"
+ __stringify(PATH_MAX)"s %*d %*d\n",
+ mountpoint, type, tokens) == 3) {
+
+ if (!path_v1[0] && !strcmp(type, "cgroup")) {
+
+ token = strtok_r(tokens, ",", &saved_ptr);
+
+ while (token != NULL) {
+ if (subsys && !strcmp(token, subsys)) {
+ strcpy(path_v1, mountpoint);
+ break;
+ }
+ token = strtok_r(NULL, ",", &saved_ptr);
+ }
+ }
+
+ if (!path_v2[0] && !strcmp(type, "cgroup2"))
+ strcpy(path_v2, mountpoint);
+
+ if (path_v1[0] && path_v2[0])
+ break;
+ }
+ fclose(fp);
+
+ if (path_v1[0])
+ path = path_v1;
+ else if (path_v2[0])
+ path = path_v2;
+ else
+ return -1;
+
+ if (strlen(path) < maxlen) {
+ strcpy(buf, path);
+ return 0;
+ }
+ return -1;
+}
diff --git a/tools/lib/api/fs/fs.c b/tools/lib/api/fs/fs.c
index 027b18f7ed8c..82f53d81a7a7 100644
--- a/tools/lib/api/fs/fs.c
+++ b/tools/lib/api/fs/fs.c
@@ -90,6 +90,7 @@ struct fs {
const char * const *mounts;
char path[PATH_MAX];
bool found;
+ bool checked;
long magic;
};
@@ -111,31 +112,37 @@ static struct fs fs__entries[] = {
.name = "sysfs",
.mounts = sysfs__fs_known_mountpoints,
.magic = SYSFS_MAGIC,
+ .checked = false,
},
[FS__PROCFS] = {
.name = "proc",
.mounts = procfs__known_mountpoints,
.magic = PROC_SUPER_MAGIC,
+ .checked = false,
},
[FS__DEBUGFS] = {
.name = "debugfs",
.mounts = debugfs__known_mountpoints,
.magic = DEBUGFS_MAGIC,
+ .checked = false,
},
[FS__TRACEFS] = {
.name = "tracefs",
.mounts = tracefs__known_mountpoints,
.magic = TRACEFS_MAGIC,
+ .checked = false,
},
[FS__HUGETLBFS] = {
.name = "hugetlbfs",
.mounts = hugetlbfs__known_mountpoints,
.magic = HUGETLBFS_MAGIC,
+ .checked = false,
},
[FS__BPF_FS] = {
.name = "bpf",
.mounts = bpf_fs__known_mountpoints,
.magic = BPF_FS_MAGIC,
+ .checked = false,
},
};
@@ -158,6 +165,7 @@ static bool fs__read_mounts(struct fs *fs)
}
fclose(fp);
+ fs->checked = true;
return fs->found = found;
}
@@ -220,6 +228,7 @@ static bool fs__env_override(struct fs *fs)
return false;
fs->found = true;
+ fs->checked = true;
strncpy(fs->path, override_path, sizeof(fs->path) - 1);
fs->path[sizeof(fs->path) - 1] = '\0';
return true;
@@ -246,6 +255,14 @@ static const char *fs__mountpoint(int idx)
if (fs->found)
return (const char *)fs->path;
+ /* the mount point was already checked for the mount point
+ * but and did not exist, so return NULL to avoid scanning again.
+ * This makes the found and not found paths cost equivalent
+ * in case of multiple calls.
+ */
+ if (fs->checked)
+ return NULL;
+
return fs__get_mountpoint(fs);
}
diff --git a/tools/lib/api/fs/fs.h b/tools/lib/api/fs/fs.h
index 92d03b8396b1..aa222ca30311 100644
--- a/tools/lib/api/fs/fs.h
+++ b/tools/lib/api/fs/fs.h
@@ -18,6 +18,18 @@
const char *name##__mount(void); \
bool name##__configured(void); \
+/*
+ * The xxxx__mountpoint() entry points find the first match mount point for each
+ * filesystems listed below, where xxxx is the filesystem type.
+ *
+ * The interface is as follows:
+ *
+ * - If a mount point is found on first call, it is cached and used for all
+ * subsequent calls.
+ *
+ * - If a mount point is not found, NULL is returned on first call and all
+ * subsequent calls.
+ */
FS(sysfs)
FS(procfs)
FS(debugfs)
@@ -28,6 +40,8 @@ FS(bpf_fs)
#undef FS
+int cgroupfs_find_mountpoint(char *buf, size_t maxlen, const char *subsys);
+
int filename__read_int(const char *filename, int *value);
int filename__read_ull(const char *filename, unsigned long long *value);
int filename__read_xll(const char *filename, unsigned long long *value);
diff --git a/tools/lib/api/io.h b/tools/lib/api/io.h
new file mode 100644
index 000000000000..777c20f6b604
--- /dev/null
+++ b/tools/lib/api/io.h
@@ -0,0 +1,115 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Lightweight buffered reading library.
+ *
+ * Copyright 2019 Google LLC.
+ */
+#ifndef __API_IO__
+#define __API_IO__
+
+#include <stdlib.h>
+#include <unistd.h>
+
+struct io {
+ /* File descriptor being read/ */
+ int fd;
+ /* Size of the read buffer. */
+ unsigned int buf_len;
+ /* Pointer to storage for buffering read. */
+ char *buf;
+ /* End of the storage. */
+ char *end;
+ /* Currently accessed data pointer. */
+ char *data;
+ /* Set true on when the end of file on read error. */
+ bool eof;
+};
+
+static inline void io__init(struct io *io, int fd,
+ char *buf, unsigned int buf_len)
+{
+ io->fd = fd;
+ io->buf_len = buf_len;
+ io->buf = buf;
+ io->end = buf;
+ io->data = buf;
+ io->eof = false;
+}
+
+/* Reads one character from the "io" file with similar semantics to fgetc. */
+static inline int io__get_char(struct io *io)
+{
+ char *ptr = io->data;
+
+ if (io->eof)
+ return -1;
+
+ if (ptr == io->end) {
+ ssize_t n = read(io->fd, io->buf, io->buf_len);
+
+ if (n <= 0) {
+ io->eof = true;
+ return -1;
+ }
+ ptr = &io->buf[0];
+ io->end = &io->buf[n];
+ }
+ io->data = ptr + 1;
+ return *ptr;
+}
+
+/* Read a hexadecimal value with no 0x prefix into the out argument hex. If the
+ * first character isn't hexadecimal returns -2, io->eof returns -1, otherwise
+ * returns the character after the hexadecimal value which may be -1 for eof.
+ * If the read value is larger than a u64 the high-order bits will be dropped.
+ */
+static inline int io__get_hex(struct io *io, __u64 *hex)
+{
+ bool first_read = true;
+
+ *hex = 0;
+ while (true) {
+ int ch = io__get_char(io);
+
+ if (ch < 0)
+ return ch;
+ if (ch >= '0' && ch <= '9')
+ *hex = (*hex << 4) | (ch - '0');
+ else if (ch >= 'a' && ch <= 'f')
+ *hex = (*hex << 4) | (ch - 'a' + 10);
+ else if (ch >= 'A' && ch <= 'F')
+ *hex = (*hex << 4) | (ch - 'A' + 10);
+ else if (first_read)
+ return -2;
+ else
+ return ch;
+ first_read = false;
+ }
+}
+
+/* Read a positive decimal value with out argument dec. If the first character
+ * isn't a decimal returns -2, io->eof returns -1, otherwise returns the
+ * character after the decimal value which may be -1 for eof. If the read value
+ * is larger than a u64 the high-order bits will be dropped.
+ */
+static inline int io__get_dec(struct io *io, __u64 *dec)
+{
+ bool first_read = true;
+
+ *dec = 0;
+ while (true) {
+ int ch = io__get_char(io);
+
+ if (ch < 0)
+ return ch;
+ if (ch >= '0' && ch <= '9')
+ *dec = (*dec * 10) + ch - '0';
+ else if (first_read)
+ return -2;
+ else
+ return ch;
+ first_read = false;
+ }
+}
+
+#endif /* __API_IO__ */
generated by cgit (git 2.34.1) at 2025-12-25 22:16:20 +0000