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tracing: only truncate ftrace files when O_TRUNC is set

The current code will truncate the ftrace files contents if O_APPEND is not set and the file is opened in write mode. This is incorrect. It should only truncate the file if O_TRUNC is set. Otherwise if one of these files is opened by a C program with fopen "r+", it will incorrectly truncate the file.

Steven Rostedt committed 17 years ago

Commit 8650ae31 parent 4c739ff3 files · +4 −4Browse files

Showing the changes to kernel/trace (3 of 3 files). Show all

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3 files
  1. kernel/trace/ftrace.c +2 −2
  2. kernel/trace/trace.c +1 −1
  3. kernel/trace/trace_events.c +1 −1
kernel/trace/ftrace.c+2−2
@@ -1662,7 +1662,7 @@ ftrace_regex_open(struct inode *inode, struct file *file, int enable) · 1661 unmodified lines
1662 1662
1663 mutex_lock(&ftrace_regex_lock);1663 mutex_lock(&ftrace_regex_lock);
1664 if ((file->f_mode & FMODE_WRITE) &&1664 if ((file->f_mode & FMODE_WRITE) &&
1665 !(file->f_flags & O_APPEND))1665 (file->f_flags & O_TRUNC))
1666 ftrace_filter_reset(enable);1666 ftrace_filter_reset(enable);
1667 1667
1668 if (file->f_mode & FMODE_READ) {1668 if (file->f_mode & FMODE_READ) {
@@ -2577,7 +2577,7 @@ ftrace_graph_open(struct inode *inode, struct file *file) · 908 unmodified lines
2577 2577
2578 mutex_lock(&graph_lock);2578 mutex_lock(&graph_lock);
2579 if ((file->f_mode & FMODE_WRITE) &&2579 if ((file->f_mode & FMODE_WRITE) &&
2580 !(file->f_flags & O_APPEND)) {2580 (file->f_flags & O_TRUNC)) {
2581 ftrace_graph_count = 0;2581 ftrace_graph_count = 0;
2582 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));2582 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
2583 }2583 }
kernel/trace/trace.c+1−1
@@ -2031,7 +2031,7 @@ static int tracing_open(struct inode *inode, struct file *file) · 2030 unmodified lines
2031 2031
2032 /* If this file was open for write, then erase contents */2032 /* If this file was open for write, then erase contents */
2033 if ((file->f_mode & FMODE_WRITE) &&2033 if ((file->f_mode & FMODE_WRITE) &&
2034 !(file->f_flags & O_APPEND)) {2034 (file->f_flags & O_TRUNC)) {
2035 long cpu = (long) inode->i_private;2035 long cpu = (long) inode->i_private;
2036 2036
2037 if (cpu == TRACE_PIPE_ALL_CPU)2037 if (cpu == TRACE_PIPE_ALL_CPU)
kernel/trace/trace_events.c+1−1
@@ -376,7 +376,7 @@ ftrace_event_seq_open(struct inode *inode, struct file *file) · 375 unmodified lines
376 const struct seq_operations *seq_ops;376 const struct seq_operations *seq_ops;
377 377
378 if ((file->f_mode & FMODE_WRITE) &&378 if ((file->f_mode & FMODE_WRITE) &&
379 !(file->f_flags & O_APPEND))379 (file->f_flags & O_TRUNC))
380 ftrace_clear_events();380 ftrace_clear_events();
381 381
382 seq_ops = inode->i_private;382 seq_ops = inode->i_private;