1#include <linux/compiler.h>
  2#include <linux/kernel.h>
  3#include <sys/types.h>
  4#include <sys/stat.h>
  5#include <unistd.h>
  6#include <string.h>
  7
  8#include "data.h"
  9#include "util.h"
 10#include "debug.h"
 11
 12static bool check_pipe(struct perf_data_file *file)
 13{
 14	struct stat st;
 15	bool is_pipe = false;
 16	int fd = perf_data_file__is_read(file) ?
 17		 STDIN_FILENO : STDOUT_FILENO;
 18
 19	if (!file->path) {
 20		if (!fstat(fd, &st) && S_ISFIFO(st.st_mode))
 21			is_pipe = true;
 22	} else {
 23		if (!strcmp(file->path, "-"))
 24			is_pipe = true;
 25	}
 26
 27	if (is_pipe)
 28		file->fd = fd;
 29
 30	return file->is_pipe = is_pipe;
 31}
 32
 33static int check_backup(struct perf_data_file *file)
 34{
 35	struct stat st;
 36
 37	if (!stat(file->path, &st) && st.st_size) {
 38		/* TODO check errors properly */
 39		char oldname[PATH_MAX];
 40		snprintf(oldname, sizeof(oldname), "%s.old",
 41			 file->path);
 42		unlink(oldname);
 43		rename(file->path, oldname);
 44	}
 45
 46	return 0;
 47}
 48
 49static int open_file_read(struct perf_data_file *file)
 50{
 51	struct stat st;
 52	int fd;
 53	char sbuf[STRERR_BUFSIZE];
 54
 55	fd = open(file->path, O_RDONLY);
 56	if (fd < 0) {
 57		int err = errno;
 58
 59		pr_err("failed to open %s: %s", file->path,
 60			strerror_r(err, sbuf, sizeof(sbuf)));
 61		if (err == ENOENT && !strcmp(file->path, "perf.data"))
 62			pr_err("  (try 'perf record' first)");
 63		pr_err("\n");
 64		return -err;
 65	}
 66
 67	if (fstat(fd, &st) < 0)
 68		goto out_close;
 69
 70	if (!file->force && st.st_uid && (st.st_uid != geteuid())) {
 71		pr_err("File %s not owned by current user or root (use -f to override)\n",
 72		       file->path);
 73		goto out_close;
 74	}
 75
 76	if (!st.st_size) {
 77		pr_info("zero-sized file (%s), nothing to do!\n",
 78			file->path);
 79		goto out_close;
 80	}
 81
 82	file->size = st.st_size;
 83	return fd;
 84
 85 out_close:
 86	close(fd);
 87	return -1;
 88}
 89
 90static int open_file_write(struct perf_data_file *file)
 91{
 92	int fd;
 93	char sbuf[STRERR_BUFSIZE];
 94
 95	if (check_backup(file))
 96		return -1;
 97
 98	fd = open(file->path, O_CREAT|O_RDWR|O_TRUNC, S_IRUSR|S_IWUSR);
 99
100	if (fd < 0)
101		pr_err("failed to open %s : %s\n", file->path,
102			strerror_r(errno, sbuf, sizeof(sbuf)));
103
104	return fd;
105}
106
107static int open_file(struct perf_data_file *file)
108{
109	int fd;
110
111	fd = perf_data_file__is_read(file) ?
112	     open_file_read(file) : open_file_write(file);
113
114	file->fd = fd;
115	return fd < 0 ? -1 : 0;
116}
117
118int perf_data_file__open(struct perf_data_file *file)
119{
120	if (check_pipe(file))
121		return 0;
122
123	if (!file->path)
124		file->path = "perf.data";
125
126	return open_file(file);
127}
128
129void perf_data_file__close(struct perf_data_file *file)
130{
131	close(file->fd);
132}
133
134ssize_t perf_data_file__write(struct perf_data_file *file,
135			      void *buf, size_t size)
136{
137	return writen(file->fd, buf, size);
138}