1// SPDX-License-Identifier: GPL-2.0
  2#include <linux/compiler.h>
  3#include <linux/kernel.h>
  4#include <sys/types.h>
  5#include <sys/stat.h>
  6#include <errno.h>
  7#include <fcntl.h>
  8#include <unistd.h>
  9#include <string.h>
 10
 11#include "data.h"
 12#include "util.h"
 13#include "debug.h"
 14
 15static bool check_pipe(struct perf_data *data)
 16{
 17	struct stat st;
 18	bool is_pipe = false;
 19	int fd = perf_data__is_read(data) ?
 20		 STDIN_FILENO : STDOUT_FILENO;
 21
 22	if (!data->file.path) {
 23		if (!fstat(fd, &st) && S_ISFIFO(st.st_mode))
 24			is_pipe = true;
 25	} else {
 26		if (!strcmp(data->file.path, "-"))
 27			is_pipe = true;
 28	}
 29
 30	if (is_pipe)
 31		data->file.fd = fd;
 32
 33	return data->is_pipe = is_pipe;
 34}
 35
 36static int check_backup(struct perf_data *data)
 37{
 38	struct stat st;
 39
 40	if (!stat(data->file.path, &st) && st.st_size) {
 41		/* TODO check errors properly */
 42		char oldname[PATH_MAX];
 43		snprintf(oldname, sizeof(oldname), "%s.old",
 44			 data->file.path);
 45		unlink(oldname);
 46		rename(data->file.path, oldname);
 47	}
 48
 49	return 0;
 50}
 51
 52static int open_file_read(struct perf_data *data)
 53{
 54	struct stat st;
 55	int fd;
 56	char sbuf[STRERR_BUFSIZE];
 57
 58	fd = open(data->file.path, O_RDONLY);
 59	if (fd < 0) {
 60		int err = errno;
 61
 62		pr_err("failed to open %s: %s", data->file.path,
 63			str_error_r(err, sbuf, sizeof(sbuf)));
 64		if (err == ENOENT && !strcmp(data->file.path, "perf.data"))
 65			pr_err("  (try 'perf record' first)");
 66		pr_err("\n");
 67		return -err;
 68	}
 69
 70	if (fstat(fd, &st) < 0)
 71		goto out_close;
 72
 73	if (!data->force && st.st_uid && (st.st_uid != geteuid())) {
 74		pr_err("File %s not owned by current user or root (use -f to override)\n",
 75		       data->file.path);
 76		goto out_close;
 77	}
 78
 79	if (!st.st_size) {
 80		pr_info("zero-sized data (%s), nothing to do!\n",
 81			data->file.path);
 82		goto out_close;
 83	}
 84
 85	data->size = st.st_size;
 86	return fd;
 87
 88 out_close:
 89	close(fd);
 90	return -1;
 91}
 92
 93static int open_file_write(struct perf_data *data)
 94{
 95	int fd;
 96	char sbuf[STRERR_BUFSIZE];
 97
 98	if (check_backup(data))
 99		return -1;
100
101	fd = open(data->file.path, O_CREAT|O_RDWR|O_TRUNC|O_CLOEXEC,
102		  S_IRUSR|S_IWUSR);
103
104	if (fd < 0)
105		pr_err("failed to open %s : %s\n", data->file.path,
106			str_error_r(errno, sbuf, sizeof(sbuf)));
107
108	return fd;
109}
110
111static int open_file(struct perf_data *data)
112{
113	int fd;
114
115	fd = perf_data__is_read(data) ?
116	     open_file_read(data) : open_file_write(data);
117
118	data->file.fd = fd;
119	return fd < 0 ? -1 : 0;
120}
121
122int perf_data__open(struct perf_data *data)
123{
124	if (check_pipe(data))
125		return 0;
126
127	if (!data->file.path)
128		data->file.path = "perf.data";
129
130	return open_file(data);
131}
132
133void perf_data__close(struct perf_data *data)
134{
135	close(data->file.fd);
136}
137
138ssize_t perf_data_file__write(struct perf_data_file *file,
139			      void *buf, size_t size)
140{
141	return writen(file->fd, buf, size);
142}
143
144ssize_t perf_data__write(struct perf_data *data,
145			      void *buf, size_t size)
146{
147	return perf_data_file__write(&data->file, buf, size);
148}
149
150int perf_data__switch(struct perf_data *data,
151			   const char *postfix,
152			   size_t pos, bool at_exit)
153{
154	char *new_filepath;
155	int ret;
156
157	if (check_pipe(data))
158		return -EINVAL;
159	if (perf_data__is_read(data))
160		return -EINVAL;
161
162	if (asprintf(&new_filepath, "%s.%s", data->file.path, postfix) < 0)
163		return -ENOMEM;
164
165	/*
166	 * Only fire a warning, don't return error, continue fill
167	 * original file.
168	 */
169	if (rename(data->file.path, new_filepath))
170		pr_warning("Failed to rename %s to %s\n", data->file.path, new_filepath);
171
172	if (!at_exit) {
173		close(data->file.fd);
174		ret = perf_data__open(data);
175		if (ret < 0)
176			goto out;
177
178		if (lseek(data->file.fd, pos, SEEK_SET) == (off_t)-1) {
179			ret = -errno;
180			pr_debug("Failed to lseek to %zu: %s",
181				 pos, strerror(errno));
182			goto out;
183		}
184	}
185	ret = data->file.fd;
186out:
187	free(new_filepath);
188	return ret;
189}