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Use dynamically-sized selected[] array for -P PATH

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While at it, added a small optimization of not remembering
the path twice if it happens to be the same.

   text	   data	    bss	    dec	    hex	filename
 245111	    680	  10860	 256651	  3ea8b	strace_old
 245075	    680	   9804	 255559	  3e647	strace

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2013-03-05 15:46:34 +01:00
parent f877982aa2
commit 7239dbcf2d
4 changed files with 22 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
defs.h
View File

@ -601,7 +601,7 @@ extern int clearbpt(struct tcb *);
extern const char *signame(int);
extern int is_restart_error(struct tcb *);
extern int pathtrace_select(const char *);
extern void pathtrace_select(const char *);
extern int pathtrace_match(struct tcb *);
extern const char *getfdpath(struct tcb *, int);

43
pathtrace.c
View File

@ -37,8 +37,8 @@
#include "syscall.h"
#define MAXSELECTED 256 /* max number of "selected" paths */
static const char *selected[MAXSELECTED]; /* paths selected for tracing */
static const char **selected = NULL; /* paths selected for tracing */
static unsigned num_selected = 0;
/*
* Return true if specified path matches one that we're tracing.
@ -46,11 +46,9 @@ static const char *selected[MAXSELECTED]; /* paths selected for tracing */
static int
pathmatch(const char *path)
{
unsigned int i;
unsigned i;
for (i = 0; i < ARRAY_SIZE(selected); ++i) {
if (selected[i] == NULL)
return 0;
for (i = 0; i < num_selected; ++i) {
if (strcmp(path, selected[i]) == 0)
return 1;
}
@ -84,21 +82,19 @@ fdmatch(struct tcb *tcp, int fd)
* Add a path to the set we're tracing.
* Secifying NULL will delete all paths.
*/
static int
static void
storepath(const char *path)
{
unsigned int i;
unsigned i;
for (i = 0; i < ARRAY_SIZE(selected); ++i) {
if (!selected[i]) {
selected[i] = path;
return 0;
}
}
if (pathmatch(path))
return; /* already in table */
fprintf(stderr, "Max trace paths exceeded, only using first %u\n",
(unsigned int) ARRAY_SIZE(selected));
return -1;
i = num_selected++;
selected = realloc(selected, num_selected * sizeof(selected[0]));
if (!selected)
die_out_of_memory();
selected[i] = path;
}
/*
@ -126,28 +122,27 @@ getfdpath(struct tcb *tcp, int fd)
* Add a path to the set we're tracing. Also add the canonicalized
* version of the path. Secifying NULL will delete all paths.
*/
int
void
pathtrace_select(const char *path)
{
char *rpath;
if (storepath(path))
return -1;
storepath(path);
rpath = realpath(path, NULL);
if (rpath == NULL)
return 0;
return;
/* if realpath and specified path are same, we're done */
if (strcmp(path, rpath) == 0) {
free(rpath);
return 0;
return;
}
fprintf(stderr, "Requested path '%s' resolved into '%s'\n",
path, rpath);
return storepath(rpath);
storepath(rpath);
}
/*
@ -159,7 +154,7 @@ pathtrace_match(struct tcb *tcp)
{
const struct_sysent *s;
if (selected[0] == NULL)
if (!selected)
return 1;
s = tcp->s_ent;

2
strace.1
View File

@ -517,7 +517,7 @@ Trace only system calls accessing
.I path.
Multiple
.B \-P
options can be used to specify up to 256 paths.
options can be used to specify several paths.
.TP
.BI "\-s " strsize
Specify the maximum string size to print (the default is 32). Note

4
strace.c
View File

@ -1649,9 +1649,7 @@ init(int argc, char *argv[])
break;
case 'P':
tracing_paths = 1;
if (pathtrace_select(optarg)) {
error_msg_and_die("Failed to select path '%s'", optarg);
}
pathtrace_select(optarg);
break;
case 's':
i = string_to_uint(optarg);