Hi Zubin, On Thu, Jun 05, 2014 at 04:49:02PM +0530, [email protected] wrote: [...] > @@ -646,6 +646,8 @@ extern const char *signame(int); > extern void pathtrace_select(const char *); > extern int pathtrace_match(struct tcb *); > extern int getfdpath(struct tcb *, int, char *, unsigned); > +extern int get_tracee_cwd(struct tcb *, char *); > +extern bool print_abspath(struct tcb *, char *, int);
Please do not export these functions unless you are going to use them
elsewhere.
> --- a/util.c
> +++ b/util.c
> @@ -571,7 +571,9 @@ void
> printpathn(struct tcb *tcp, long addr, int n)
> {
> char path[MAXPATHLEN + 1];
> + char cwd[MAXPATHLEN + 1];
> int nul_seen;
> + int valid_length = 1;
Please move these new objects to the branch where they are going to be used.
btw, your get_tracee_cwd may write up to MAXPATHLEN+2 bytes.
> if (!addr) {
> tprints("NULL");
> @@ -593,8 +595,28 @@ printpathn(struct tcb *tcp, long addr, int n)
> n++;
> outstr = alloca(4 * n); /* 4*(n-1) + 3 for quotes and NUL */
> string_quote(path, outstr, -1, n);
> +
> + /* If -yy is used and the path is not absolute, find the cwd of
> the tracee
> + and print that out first */
> + if (show_fd_path == 2 && outstr[1] != '/') {
1. show_fd_path > 1
2. path[0] != '/' (think of strace -xx)
> + /* If the call to get_tracee_cwd succeeds, we
> concatenate the
> + cwd and outstr and print it out. If the call fails,
> we just
> + print out the relative path. */
> + char *outcwd;
> + int cwd_len;
> + cwd_len = get_tracee_cwd(tcp, cwd);
> + if (cwd_len != -1) {
> + outcwd = alloca(4 * cwd_len);
4 * cwd_len may be not enough.
> + string_quote(cwd, outcwd, -1, cwd_len+1);
> + outcwd[strlen(outcwd)-1] = '\0';
The string made by string_quote is already null-terminated.
> + tprintf("%s", outcwd);
Please use tprints for this.
> + if (strlen(cwd) + strlen(outstr) > MAXPATHLEN)
> + valid_length = 0;
> + }
> + }
> + if (show_fd_path == 2) outstr += 1;
> tprints(outstr);
> - if (!nul_seen)
> + if (!nul_seen || (show_fd_path==2) && !valid_length)
> tprints("...");
I don't see why our decision on printing trailing dots should depend on
get_tracee_cwd.
I think it would be better just to print cwd prefix if required conditions
are met:
char *outstr;
path[n] = '\0';
if (show_fd_path > 1 && *path && *path != '/')
print_tracee_cwd(tcp);
n++;
outstr = alloca(4 * n); /* 4*(n-1) + 3 for quotes and NUL */
string_quote(path, outstr, -1, n);
tprints(outstr);
if (!nul_seen)
tprints("...");
> @@ -1549,3 +1571,29 @@ clearbpt(struct tcb *tcp)
> tcp->flags &= ~TCB_BPTSET;
> return 0;
> }
> +
> +/* Return the current working directory of the tracee process,
> + with a trailing slash. */
> +int
> +get_tracee_cwd(struct tcb *tcp, char *cwd)
> +{
> + int link_size = sizeof("/proc/%u/cwd") + sizeof(int) * 3;
> + char linkpath[link_size];
> + ssize_t n;
> +
> + snprintf(linkpath, link_size, "/proc/%u/cwd", tcp->pid);
> + n = readlink(linkpath, cwd, MAXPATHLEN);
> +
> + /* If readlink fails, something is abnormal(path > 4096) about
> + the traced process and its cwd, so return an empty cwd. */
> + if (n == -1) {
> + cwd[0] = '\0';
> + return n;
> + }
> +
> + if (n >= 0) {
> + cwd[n] = '/';
> + cwd[n+1] = '\0';
> + }
> + return n+1;
> +}
(n > 0) is the only case when we have a cwd prefix to print,
(n == 0) is even more odd than (n < 0).
--
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