[PATCH v5] Print absolute paths in printpathn when -yy is used
Zubin Mithra
zubin.mithra at gmail.com
Sun Aug 24 19:22:12 UTC 2014
Hi Dmitry,
Please find below a diff of the changes for having `renameat` decode paths using oldfd and newfd. Other *at syscalls could be modified similarly. Does this look good?
diff --git a/defs.h b/defs.h
index 4aedee3..97a0c08 100644
--- a/defs.h
+++ b/defs.h
@@ -679,7 +679,9 @@ extern void printstr(struct tcb *, long, long);
extern void printnum(struct tcb *, long, const char *);
extern void printnum_int(struct tcb *, long, const char *);
extern void printpath(struct tcb *, long);
+extern void printpathat(struct tcb *, int, long);
extern void printpathn(struct tcb *, long, int);
+extern void printpathnat(struct tcb *, int, long, int);
#define TIMESPEC_TEXT_BUFSIZE (sizeof(long)*3 * 2 + sizeof("{%u, %u}"))
#define TIMEVAL_TEXT_BUFSIZE TIMESPEC_TEXT_BUFSIZE
extern void printtv_bitness(struct tcb *, long, enum bitness_t, int);
diff --git a/file.c b/file.c
index 360408f..f6f6a37 100644
--- a/file.c
+++ b/file.c
@@ -1772,10 +1772,10 @@ sys_renameat(struct tcb *tcp)
{
if (entering(tcp)) {
print_dirfd(tcp, tcp->u_arg[0]);
- printpath(tcp, tcp->u_arg[1]);
+ printpathat(tcp, tcp->u_arg[0], tcp->u_arg[1]);
tprints(", ");
print_dirfd(tcp, tcp->u_arg[2]);
- printpath(tcp, tcp->u_arg[3]);
+ printpathat(tcp, tcp->u_arg[2], tcp->u_arg[3]);
}
return 0;
}
diff --git a/strace.c b/strace.c
index 0292c96..8b3adb2 100644
--- a/strace.c
+++ b/strace.c
@@ -204,6 +204,7 @@ usage: strace [-CdffhiqrtttTvVxxy] [-I n] [-e expr]...\n\
-p pid... / [-D] [-E var=val]... [-u username] PROG [ARGS]\n\
or: strace -c[df] [-I n] [-e expr]... [-O overhead] [-S sortby]\n\
-p pid... / [-D] [-E var=val]... [-u username] PROG [ARGS]\n\
+-A -- print absolute paths instead of relative paths everywhere\n\
-c -- count time, calls, and errors for each syscall and report summary\n\
-C -- like -c but also print regular output\n\
-w -- summarise syscall latency (default is system time)\n\
@@ -1678,6 +1679,7 @@ init(int argc, char *argv[])
#ifdef USE_LIBUNWIND
"k"
#endif
+ "A"
"D"
"a:e:o:O:p:s:S:u:E:P:I:")) != EOF) {
switch (c) {
diff --git a/util.c b/util.c
index 6d70623..e5a29b2 100644
--- a/util.c
+++ b/util.c
@@ -405,7 +405,8 @@ printfd(struct tcb *tcp, int fd)
{
char path[PATH_MAX + 1];
- if (show_fd_path && getfdpath(tcp, fd, path, sizeof(path)) >= 0)
+ if ((show_fd_path || show_abs_path) &&
+ getfdpath(tcp, fd, path, sizeof(path)) >= 0)
tprintf("%d<%s>", fd, path);
else
tprintf("%d", fd);
@@ -590,12 +591,8 @@ print_tracee_cwd(struct tcb *tcp)
return false;
}
-/*
- * Print path string specified by address `addr' and length `n'.
- * If path length exceeds `n', append `...' to the output.
- */
void
-printpathn(struct tcb *tcp, long addr, int n)
+printpath_common(struct tcb *tcp, int fd, long addr, int n)
{
char path[MAXPATHLEN + 1];
int nul_seen;
@@ -618,13 +615,28 @@ printpathn(struct tcb *tcp, long addr, int n)
bool prefix_printed = false;
path[n] = '\0';
- if (show_fd_path > 1 && *path && *path != '/')
+
+ /* If the call comes from `printpathn' and -y is used */
+ if (fd == -1 && show_fd_path && *path && *path != '/')
prefix_printed = print_tracee_cwd(tcp);
+
+ /* If the call comes from `printpathnat' and -A is used */
+ else if (show_abs_path && *path && *path != '/') {
+ if (fd == AT_FDCWD)
+ prefix_printed = print_tracee_cwd(tcp);
+ else {
+ char path[PATH_MAX + 1];
+ getfdpath(tcp, fd, path, sizeof(path));
+ tprintf("\"%s/", path);
+ prefix_printed = 1;
+ }
+ }
+
n++;
outstr = alloca(4 * n); /* 4*(n-1) + 3 for quotes and NUL */
string_quote(path, outstr, -1, n);
- /* Dont print opening quotes if cwd is printed */
+ /* Dont print opening quotes if cwd/decoded dirfd is printed */
if (prefix_printed)
outstr += 1;
tprints(outstr);
@@ -634,6 +646,24 @@ printpathn(struct tcb *tcp, long addr, int n)
}
void
+printpathnat(struct tcb *tcp, int fd, long addr, int n)
+{
+ printpath_common(tcp, fd, addr, n);
+}
+
+void
+printpathat(struct tcb *tcp, int fd, long addr)
+{
+ printpathnat(tcp, fd, addr, MAXPATHLEN);
+}
+
+void
+printpathn(struct tcb *tcp, long addr, int n)
+{
+ printpath_common(tcp, -1, addr, n);
+}
+
+void
printpath(struct tcb *tcp, long addr)
{
/* Size must correspond to char path[] size in printpathn */
Thanks!
-- zm
On 20-Aug-2014, at 18:56, Dmitry V. Levin <ldv at altlinux.org> wrote:
> On Mon, Aug 11, 2014 at 09:31:25AM +0530, Zubin Mithra wrote:
> [...]
>> Currently this is how I've implemented it(this is a portion of the diff
>> minus the usage/documentation/variable declaration/print_tracee_cwd
>> function for brevity).
>>
>> diff --git a/util.c b/util.c
>> index c78e962..57ea9fe 100644
>> --- a/util.c
>> +++ b/util.c
>> @@ -559,6 +559,60 @@ string_quote(const char *instr, char *outstr, long
>> len, int size)
>> return 0;
>> }
>> +
>> +/* Returns the index of the dirfd to be decoded if the syscall
>> + * is a *at syscall */
>> +static bool
>> +is_at_syscall(struct tcb *tcp)
>> +{
>> + if (tcp->s_ent->sys_func == sys_openat ||
>> + tcp->s_ent->sys_func == sys_mkdirat ||
>> + tcp->s_ent->sys_func == sys_mknodat ||
>> + tcp->s_ent->sys_func == sys_fchownat ||
>> + tcp->s_ent->sys_func == sys_futimesat ||
>> + tcp->s_ent->sys_func == sys_newfstatat ||
>> + tcp->s_ent->sys_func == sys_unlinkat ||
>> + tcp->s_ent->sys_func == sys_renameat ||
>> + tcp->s_ent->sys_func == sys_linkat ||
>> + tcp->s_ent->sys_func == sys_readlinkat ||
>> + tcp->s_ent->sys_func == sys_fchmodat ||
>> + tcp->s_ent->sys_func == sys_faccessat)
>> + return 0;
>> + else if (tcp->s_ent->sys_func == sys_symlinkat)
>> + return 1;
>> + return -1;
>
> This won't work for renameat, renameat2, and linkat syscalls.
> A more robust approach is to introduce a new printing function, e.g.
> printpathat, and use it in these decoders.
>
>
> --
> ldv
> ------------------------------------------------------------------------------
> Slashdot TV.
> Video for Nerds. Stuff that matters.
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