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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 
check_pipe(struct perf_data_file * file)12 static 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 
check_backup(struct perf_data_file * file)33 static 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 
open_file_read(struct perf_data_file * file)49 static 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 
open_file_write(struct perf_data_file * file)90 static 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 
open_file(struct perf_data_file * file)107 static 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 
perf_data_file__open(struct perf_data_file * file)118 int 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 
perf_data_file__close(struct perf_data_file * file)129 void perf_data_file__close(struct perf_data_file *file)
130 {
131 	close(file->fd);
132 }
133 
perf_data_file__write(struct perf_data_file * file,void * buf,size_t size)134 ssize_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 }
139