[英]Linux posix C regexec() not returning all matches
我有以下腳本來解析要查找字符串匹配的進程內存,一切正常,但轉儲具有1193
可能匹配項的編輯器進程(在本例中為“ nano”)(如果我轉儲內存然后對其執行egrep,則可以正常工作)但是我的代碼只輸出3
匹配項。 任何想法?
#ifdef TARGET_64
// for 64bit target (see /proc/cpuinfo addr size virtual)
#define MEM_MAX (1ULL << 48)
#else
#define MEM_MAX (1ULL << 32)
#endif
#define _LARGEFILE64_SOURCE
#include <unistd.h>
#include <stdio.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/ptrace.h>
#include <regex.h>
int main(int argc, char **argv)
{
if (argc < 2) {
printf("Usage: %s <pid>\n", argv[0]);
exit(1);
}
char buf[128];
int pid = atoi(argv[1]);
snprintf(buf, sizeof(buf), "/proc/%d/mem", pid);
int fd = open(buf, O_RDONLY);
if (fd == -1) {
fprintf(stderr, "Error opening mem file: %m\n");
exit(1);
}
int status ,i;
int cflags = REG_EXTENDED;
regmatch_t pmatch[1];
const size_t nmatch=1;
regex_t reg;
const char *pattern="([a-zA-Z]{18,20})";
regcomp(®, pattern, cflags);
long ptret = ptrace(PTRACE_ATTACH, pid, 0, 0);
if (ptret == -1) {
fprintf(stderr, "Ptrace failed: %s\n", strerror(errno));
close(fd);
exit(1);
}
unsigned char page[4096];
unsigned long long offset = 0;
while (offset < MEM_MAX) {
lseek64(fd, offset, SEEK_SET);
ssize_t ret;
ret = read(fd, page, sizeof(page));
if (ret > 0) {
status = regexec(®, page, nmatch, pmatch, 0);
if(status == 0){
for (i=pmatch[0].rm_so; i<pmatch[0].rm_eo; ++i) {
putchar(page[i]);
}
printf("\n");
}
}
offset += sizeof(page);
}
ptrace(PTRACE_DETACH, pid, 0, 0);
close(fd);
regfree(®);
return 0;
}
pid為2208
nano,其中18-20
字符之間的[ Read 1193 lines ]
為alpha
:
root ~/coding/proc/regex # ./memregmatch 22008
ABCABCABCABCABCABC
ABCABCABCABCABCABCAC
ABCCBAABCCBAABCCBABA
root ~/coding/proc/regex #
好的,用libpcre
:
#include <pcre.h>
#include <locale.h>
....
const char *error;
int erroffset;
pcre *re;
int rc;
int i;
int ovector[100];
char *regex = "([a-zA-Z]{18,20})";
re = pcre_compile (regex, /* the pattern */
PCRE_MULTILINE|PCRE_DOTALL|PCRE_NEWLINE_ANYCRLF,
&error, /* for error message */
&erroffset, /* for error offset */
0); /* use default character tables */
if (!re)
{
printf("pcre_compile failed (offset: %d), %s\n", erroffset, error);
return -1;
}
....
if (ret > 0) {
//
unsigned int offset = 0;
while (offset < sizeof(page) && (rc = pcre_exec(re, 0, page, sizeof(page), offset, 0, ovector, sizeof(ovector))) >= 0)
{
for(i = 0; i < rc; ++i)
{
printf("%.*s\n", ovector[2*i+1] - ovector[2*i], page + ovector[2*i]);
}
offset = ovector[1];
}
//
}
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