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/*
* Totally braindamaged mbox splitter program.
*
* It just splits a mbox into a list of files: "0001" "0002" ..
* so you can process them further from there.
*/
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <string.h>
#include <stdio.h>
#include <ctype.h>
#include <assert.h>
static int usage(void)
{
fprintf(stderr, "mailsplit <mbox> <directory>\n");
exit(1);
}
static int linelen(const char *map, unsigned long size)
{
int len = 0, c;
do {
c = *map;
map++;
size--;
len++;
} while (size && c != '\n');
return len;
}
static int is_from_line(const char *line, int len)
{
const char *colon;
if (len < 20 || memcmp("From ", line, 5))
return 0;
colon = line + len - 2;
line += 5;
for (;;) {
if (colon < line)
return 0;
if (*--colon == ':')
break;
}
if (!isdigit(colon[-4]) ||
!isdigit(colon[-2]) ||
!isdigit(colon[-1]) ||
!isdigit(colon[ 1]) ||
!isdigit(colon[ 2]))
return 0;
/* year */
if (strtol(colon+3, NULL, 10) <= 90)
return 0;
/* Ok, close enough */
return 1;
}
static int parse_email(const void *map, unsigned long size)
{
unsigned long offset;
if (size < 6 || memcmp("From ", map, 5))
goto corrupt;
/* Make sure we don't trigger on this first line */
map++; size--; offset=1;
/*
* Search for a line beginning with "From ", and
* having something that looks like a date format.
*/
do {
int len = linelen(map, size);
if (is_from_line(map, len))
return offset;
map += len;
size -= len;
offset += len;
} while (size);
return offset;
corrupt:
fprintf(stderr, "corrupt mailbox\n");
exit(1);
}
int main(int argc, char **argv)
{
int fd, nr;
struct stat st;
unsigned long size;
void *map;
if (argc != 3)
usage();
fd = open(argv[1], O_RDONLY);
if (fd < 0) {
perror(argv[1]);
exit(1);
}
if (chdir(argv[2]) < 0)
usage();
if (fstat(fd, &st) < 0) {
perror("stat");
exit(1);
}
size = st.st_size;
map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
if (map == MAP_FAILED) {
perror("mmap");
close(fd);
exit(1);
}
close(fd);
nr = 0;
do {
char name[10];
unsigned long len = parse_email(map, size);
assert(len <= size);
sprintf(name, "%04d", ++nr);
fd = open(name, O_WRONLY | O_CREAT | O_EXCL, 0600);
if (fd < 0) {
perror(name);
exit(1);
}
if (write(fd, map, len) != len) {
perror("write");
exit(1);
}
close(fd);
map += len;
size -= len;
} while (size > 0);
return 0;
}
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