linux/tools/perf/util/data.c
Arnaldo Carvalho de Melo c8b5f2c96d tools: Introduce str_error_r()
The tools so far have been using the strerror_r() GNU variant, that
returns a string, be it the buffer passed or something else.

But that, besides being tricky in cases where we expect that the
function using strerror_r() returns the error formatted in a provided
buffer (we have to check if it returned something else and copy that
instead), breaks the build on systems not using glibc, like Alpine
Linux, where musl libc is used.

So, introduce yet another wrapper, str_error_r(), that has the GNU
interface, but uses the portable XSI variant of strerror_r(), so that
users rest asured that the provided buffer is used and it is what is
returned.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-d4t42fnf48ytlk8rjxs822tf@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-07-12 15:19:47 -03:00

180 lines
3.4 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"
#include "debug.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;
char sbuf[STRERR_BUFSIZE];
fd = open(file->path, O_RDONLY);
if (fd < 0) {
int err = errno;
pr_err("failed to open %s: %s", file->path,
str_error_r(err, sbuf, sizeof(sbuf)));
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 (use -f to override)\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;
char sbuf[STRERR_BUFSIZE];
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,
str_error_r(errno, sbuf, sizeof(sbuf)));
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);
}
int perf_data_file__switch(struct perf_data_file *file,
const char *postfix,
size_t pos, bool at_exit)
{
char *new_filepath;
int ret;
if (check_pipe(file))
return -EINVAL;
if (perf_data_file__is_read(file))
return -EINVAL;
if (asprintf(&new_filepath, "%s.%s", file->path, postfix) < 0)
return -ENOMEM;
/*
* Only fire a warning, don't return error, continue fill
* original file.
*/
if (rename(file->path, new_filepath))
pr_warning("Failed to rename %s to %s\n", file->path, new_filepath);
if (!at_exit) {
close(file->fd);
ret = perf_data_file__open(file);
if (ret < 0)
goto out;
if (lseek(file->fd, pos, SEEK_SET) == (off_t)-1) {
ret = -errno;
pr_debug("Failed to lseek to %zu: %s",
pos, strerror(errno));
goto out;
}
}
ret = file->fd;
out:
free(new_filepath);
return ret;
}