tools/perf/util/data.c

   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
  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
  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
  49 static int open_file_read(struct perf_data_file *file)
  50 {
  51         struct stat st;
  52         int fd;
  53
  54         fd = open(file->path, O_RDONLY);
  55         if (fd < 0) {
  56                 int err = errno;
  57
  58                 pr_err("failed to open %s: %s", file->path, strerror(err));
  59                 if (err == ENOENT && !strcmp(file->path, "perf.data"))
  60                         pr_err("  (try 'perf record' first)");
  61                 pr_err("\n");
  62                 return -err;
  63         }
  64
  65         if (fstat(fd, &st) < 0)
  66                 goto out_close;
  67
  68         if (!file->force && st.st_uid && (st.st_uid != geteuid())) {
  69                 pr_err("File %s not owned by current user or root (use -f to override)\n",
  70                        file->path);
  71                 goto out_close;
  72         }
  73
  74         if (!st.st_size) {
  75                 pr_info("zero-sized file (%s), nothing to do!\n",
  76                         file->path);
  77                 goto out_close;
  78         }
  79
  80         file->size = st.st_size;
  81         return fd;
  82
  83  out_close:
  84         close(fd);
  85         return -1;
  86 }
  87
  88 static int open_file_write(struct perf_data_file *file)
  89 {
  90         int fd;
  91
  92         if (check_backup(file))
  93                 return -1;
  94
  95         fd = open(file->path, O_CREAT|O_RDWR|O_TRUNC, S_IRUSR|S_IWUSR);
  96
  97         if (fd < 0)
  98                 pr_err("failed to open %s : %s\n", file->path, strerror(errno));
  99
 100         return fd;
 101 }
 102
 103 static int open_file(struct perf_data_file *file)
 104 {
 105         int fd;
 106
 107         fd = perf_data_file__is_read(file) ?
 108              open_file_read(file) : open_file_write(file);
 109
 110         file->fd = fd;
 111         return fd < 0 ? -1 : 0;
 112 }
 113
 114 int perf_data_file__open(struct perf_data_file *file)
 115 {
 116         if (check_pipe(file))
 117                 return 0;
 118
 119         if (!file->path)
 120                 file->path = "perf.data";
 121
 122         return open_file(file);
 123 }
 124
 125 void perf_data_file__close(struct perf_data_file *file)
 126 {
 127         close(file->fd);
 128 }
 129
 130 ssize_t perf_data_file__write(struct perf_data_file *file,
 131                               void *buf, size_t size)
 132 {
 133         return writen(file->fd, buf, size);
 134 }