[PATCH] util.c (string_quote): quote unprintable chars
Dmitry V. Levin
ldv at altlinux.org
Mon Oct 8 21:40:33 UTC 2007
On Wed, Sep 26, 2007 at 03:48:39PM +0100, Neil Campbell wrote:
> Dmitry V. Levin wrote:
> > On Wed, Sep 26, 2007 at 10:28:58AM +0100, Neil Campbell wrote:
> >> Dmitry V. Levin wrote:
> >> > On Sat, Aug 25, 2007 at 01:21:00PM +0100, Neil Campbell wrote:
> >> >> I was tracing some applications and found that the output of strace
> >> >> included some non-printable characters, leading various tools such as
> >> >> 'file' and 'less' to refuse to recognise the file as text. It seemed
> >> >> that this was due to some strange paths being included in unix domain
> >> >> sockaddr structs.
> >> > I propose another patch to avoid unprintable characters in output.
> >>
> >> In most cases however this path will be a genuine path to a file, and
> >> the current code in CVS will print this in full, which is consistent
> >> with how paths are handled elsewhere.
> >
> > That is, you suggest to use printpathn() instead?
>
> I'm not very familiar with the strace source, but this doesn't appear
> to escape
> the non-printable characters - if such support was added to printpath
> then yes,
> that would sound good to me.
I see no reason why printpath() should not quote unprintable chars like
printstr() does. For example, if open() is calles with unprintable file
name, why shouldn't it be printed quoted?
Here is proposed change. It may look a bit complicated due to code
relocation from one function to another, though.
2007-10-01 Dmitry V. Levin <ldv at altlinux.org>
* util.c (string_quote): Move quoting code from ...
(printstr) ... here. Use string_quote.
(printpathn): Update for new string_quote interface.
(printpath): Use printpathn.
--- strace/util.c
+++ strace/util.c
@@ -408,72 +408,125 @@
static char path[MAXPATHLEN + 1];
static void
-string_quote(str)
-const char *str;
+string_quote(const char *instr, char *outstr, int len, int size)
{
- char buf[2 * MAXPATHLEN + 1];
- char *s;
+ const unsigned char *ustr = (const unsigned char *) instr;
+ char *s = outstr;
+ int usehex = 0, c, i;
- if (!strpbrk(str, "\"\'\\")) {
- tprintf("\"%s\"", str);
- return;
+ if (xflag > 1)
+ usehex = 1;
+ else if (xflag) {
+ for (i = 0; i < size; ++i) {
+ c = ustr[i];
+ if (len < 0 && c == '\0')
+ break;
+ if (!isprint(c) && !isspace(c)) {
+ usehex = 1;
+ break;
+ }
+ }
}
- for (s = buf; *str; str++) {
- switch (*str) {
- case '\"': case '\'': case '\\':
- *s++ = '\\'; *s++ = *str; break;
- default:
- *s++ = *str; break;
+
+ *s++ = '\"';
+
+ if (usehex) {
+ for (i = 0; i < size; ++i) {
+ c = ustr[i];
+ if (len < 0 && c == '\0')
+ break;
+ sprintf(s, "\\x%02x", c);
+ s += 4;
+ }
+ } else {
+ for (i = 0; i < size; ++i) {
+ c = ustr[i];
+ if (len < 0 && c == '\0')
+ break;
+ switch (c) {
+ case '\"': case '\\':
+ *s++ = '\\';
+ *s++ = c;
+ break;
+ case '\f':
+ *s++ = '\\';
+ *s++ = 'f';
+ break;
+ case '\n':
+ *s++ = '\\';
+ *s++ = 'n';
+ break;
+ case '\r':
+ *s++ = '\\';
+ *s++ = 'r';
+ break;
+ case '\t':
+ *s++ = '\\';
+ *s++ = 't';
+ break;
+ case '\v':
+ *s++ = '\\';
+ *s++ = 'v';
+ break;
+ default:
+ if (isprint(c))
+ *s++ = c;
+ else if (i + 1 < size
+ && isdigit(ustr[i + 1])) {
+ sprintf(s, "\\%03o", c);
+ s += 4;
+ } else {
+ sprintf(s, "\\%o", c);
+ s += strlen(s);
+ }
+ break;
+ }
}
}
- *s = '\0';
- tprintf("\"%s\"", buf);
-}
-void
-printpath(tcp, addr)
-struct tcb *tcp;
-long addr;
-{
- if (addr == 0)
- tprintf("NULL");
- else if (umovestr(tcp, addr, MAXPATHLEN, path) < 0)
- tprintf("%#lx", addr);
- else
- string_quote(path);
- return;
+ *s++ = '\"';
+ *s = '\0';
}
void
-printpathn(tcp, addr, n)
-struct tcb *tcp;
-long addr;
-int n;
+printpathn(struct tcb *tcp, long addr, int n)
{
- if (n >= sizeof path)
+ if (n > sizeof path - 1)
n = sizeof path - 1;
- if (addr == 0)
+ if (addr == 0) {
tprintf("NULL");
- else if (umovestr(tcp, addr, n, path) < 0)
+ return;
+ }
+
+ path[n] = '\0';
+ if (umovestr(tcp, addr, n + 1, path) < 0)
tprintf("%#lx", addr);
else {
- path[n] = '\0';
- string_quote(path);
+ static char outstr[4*(sizeof path - 1) + sizeof "\"...\""];
+ int trunc = (path[n] != '\0');
+
+ if (trunc)
+ path[n] = '\0';
+ string_quote(path, outstr, -1, n);
+ if (trunc)
+ strcat(outstr, "...");
+ tprintf("%s", outstr);
}
}
void
-printstr(tcp, addr, len)
-struct tcb *tcp;
-long addr;
-int len;
+printpath(struct tcb *tcp, long addr)
{
- static unsigned char *str = NULL;
+ printpathn(tcp, addr, sizeof path - 1);
+}
+
+void
+printstr(struct tcb *tcp, long addr, int len)
+{
+ static char *str = NULL;
static char *outstr;
- int i, n, c, usehex;
- char *s, *outend;
- int trunc;
+ int size, trunc;
if (!addr) {
tprintf("NULL");
@@ -488,94 +541,27 @@ printstr(tcp, addr, len)
return;
}
}
- outend = outstr + max_strlen * 4;
+
if (len < 0) {
- n = max_strlen + 1;
- if (umovestr(tcp, addr, n, (char *) str) < 0) {
+ size = max_strlen + 1;
+ if (umovestr(tcp, addr, size, str) < 0) {
tprintf("%#lx", addr);
return;
}
}
else {
- n = MIN(len, max_strlen + 1);
- if (umoven(tcp, addr, n, (char *) str) < 0) {
+ size = MIN(len, max_strlen + 1);
+ if (umoven(tcp, addr, size, str) < 0) {
tprintf("%#lx", addr);
return;
}
}
- trunc = n > max_strlen && str[--n] != 0;
-
- usehex = 0;
- if (xflag > 1)
- usehex = 1;
- else if (xflag) {
- for (i = 0; i < n; i++) {
- c = str[i];
- if (len < 0 && c == '\0')
- break;
- if (!isprint(c) && !isspace(c)) {
- usehex = 1;
- break;
- }
- }
- }
-
- s = outstr;
- *s++ = '\"';
-
- if (usehex) {
- for (i = 0; i < n; i++) {
- c = str[i];
- if (len < 0 && c == '\0')
- break;
- sprintf(s, "\\x%02x", c);
- s += 4;
- if (s > outend)
- break;
- }
- }
- else {
- for (i = 0; i < n; i++) {
- c = str[i];
- if (len < 0 && c == '\0')
- break;
- switch (c) {
- case '\"': case '\'': case '\\':
- *s++ = '\\'; *s++ = c; break;
- case '\f':
- *s++ = '\\'; *s++ = 'f'; break;
- case '\n':
- *s++ = '\\'; *s++ = 'n'; break;
- case '\r':
- *s++ = '\\'; *s++ = 'r'; break;
- case '\t':
- *s++ = '\\'; *s++ = 't'; break;
- case '\v':
- *s++ = '\\'; *s++ = 'v'; break;
- default:
- if (isprint(c))
- *s++ = c;
- else if (i < n - 1 && isdigit(str[i + 1])) {
- sprintf(s, "\\%03o", c);
- s += 4;
- }
- else {
- sprintf(s, "\\%o", c);
- s += strlen(s);
- }
- break;
- }
- if (s > outend)
- break;
- }
- }
+ trunc = size > max_strlen && str[--size] != 0;
+ string_quote(str, outstr, len, size);
+ if (size < len || (len < 0 && trunc))
+ strcat(outstr, "...");
- *s++ = '\"';
- if (i < len || (len < 0 && (trunc || s > outend))) {
- *s++ = '.'; *s++ = '.'; *s++ = '.';
- }
- *s = '\0';
tprintf("%s", outstr);
}
--
ldv
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