alistair23-linux/tools/perf/util/data.c
Adrien BAK ffa91880a9 perf tools: Improve error reporting
In the current version, when using perf record, if something goes
wrong in tools/perf/builtin-record.c:375
  session = perf_session__new(file, false, NULL);

The error message:
"Not enough memory for reading per file header"

is issued. This error message seems to be outdated and is not very
helpful. This patch proposes to replace this error message by
"Perf session creation failed"

I believe this issue has been brought to lkml:
https://lkml.org/lkml/2014/2/24/458
although this patch only tackles a (small) part of the issue.

Additionnaly, this patch improves error reporting in
tools/perf/util/data.c open_file_write.

Currently, if the call to open fails, the user is unaware of it.
This patch logs the error, before returning the error code to
the caller.

Reported-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Adrien BAK <adrien.bak@metascale.org>
Link: http://lkml.kernel.org/r/1397786443.3093.4.camel@beast
[ Reorganize the changelog into paragraphs ]
[ Added empty line after fd declaration in open_file_write ]
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
2014-04-20 00:15:12 +02:00

134 lines
2.4 KiB
C

#include <linux/compiler.h>
#include <linux/kernel.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <string.h>
#include "data.h"
#include "util.h"
static bool check_pipe(struct perf_data_file *file)
{
struct stat st;
bool is_pipe = false;
int fd = perf_data_file__is_read(file) ?
STDIN_FILENO : STDOUT_FILENO;
if (!file->path) {
if (!fstat(fd, &st) && S_ISFIFO(st.st_mode))
is_pipe = true;
} else {
if (!strcmp(file->path, "-"))
is_pipe = true;
}
if (is_pipe)
file->fd = fd;
return file->is_pipe = is_pipe;
}
static int check_backup(struct perf_data_file *file)
{
struct stat st;
if (!stat(file->path, &st) && st.st_size) {
/* TODO check errors properly */
char oldname[PATH_MAX];
snprintf(oldname, sizeof(oldname), "%s.old",
file->path);
unlink(oldname);
rename(file->path, oldname);
}
return 0;
}
static int open_file_read(struct perf_data_file *file)
{
struct stat st;
int fd;
fd = open(file->path, O_RDONLY);
if (fd < 0) {
int err = errno;
pr_err("failed to open %s: %s", file->path, strerror(err));
if (err == ENOENT && !strcmp(file->path, "perf.data"))
pr_err(" (try 'perf record' first)");
pr_err("\n");
return -err;
}
if (fstat(fd, &st) < 0)
goto out_close;
if (!file->force && st.st_uid && (st.st_uid != geteuid())) {
pr_err("file %s not owned by current user or root\n",
file->path);
goto out_close;
}
if (!st.st_size) {
pr_info("zero-sized file (%s), nothing to do!\n",
file->path);
goto out_close;
}
file->size = st.st_size;
return fd;
out_close:
close(fd);
return -1;
}
static int open_file_write(struct perf_data_file *file)
{
int fd;
if (check_backup(file))
return -1;
fd = open(file->path, O_CREAT|O_RDWR|O_TRUNC, S_IRUSR|S_IWUSR);
if (fd < 0)
pr_err("failed to open %s : %s\n", file->path, strerror(errno));
return fd;
}
static int open_file(struct perf_data_file *file)
{
int fd;
fd = perf_data_file__is_read(file) ?
open_file_read(file) : open_file_write(file);
file->fd = fd;
return fd < 0 ? -1 : 0;
}
int perf_data_file__open(struct perf_data_file *file)
{
if (check_pipe(file))
return 0;
if (!file->path)
file->path = "perf.data";
return open_file(file);
}
void perf_data_file__close(struct perf_data_file *file)
{
close(file->fd);
}
ssize_t perf_data_file__write(struct perf_data_file *file,
void *buf, size_t size)
{
return writen(file->fd, buf, size);
}