129 lines
3.9 KiB
C
129 lines
3.9 KiB
C
#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <sys/param.h>
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#include <fcntl.h>
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#include <ctype.h>
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#include "externs.h"
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static char *filename;
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static char *end_rcs_header;
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static char * skipblanks(char *cp)
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{
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while (isspace(*cp)) cp++;
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return cp;
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}
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static int check (char *p, char *msg) {
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if (p == NULL || p > end_rcs_header)
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{ warn (msg, filename); return -1; }
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return 0;
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}
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static int pagesize = 0;
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void readrcs (char *f, char **revpp, char **lockpp, char **datepp, char **authpp) {
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int fd = -1;
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struct stat64 sbuf;
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char *buf = (char *)MAP_FAILED, *p, *q;
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char *revbuf = NULL, *revp, *lockp, *datep, *authp;
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long revlen;
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if (!pagesize)
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pagesize = getpagesize();
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filename = f;
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if ((fd = open (filename, O_RDONLY)) < 0)
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{ warn ("open:", filename); goto fail1; }
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if (fstat64 (fd, &sbuf) < 0)
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{ warn ("stat64:", filename); goto fail1; }
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if (sbuf.st_size == 0)
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{ warn ("zero length file:", filename); goto fail1; }
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buf = (char *)mmap((void *)0, sbuf.st_size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
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if (buf == (char *)MAP_FAILED)
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{ warn ("mmap:", filename); goto fail1; }
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if (strncmp (buf, "head", sizeof("head")-1) != 0)
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{ warn ("missing head:", filename); goto fail1; }
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/*
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* The strstr calls presume that there is at least one nul character
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* following all the valid data. The mmap gives us this, except in
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* the case that the mapped file ends exactly on a page boundary.
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* In that case we overwrite the last character in the file with a nul.
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*
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* This slight disregard for the file's data is actually user visible:
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* Truncate an RCS ,v file so that it ends with "\ndesc\n". If the file
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* is any size other than a page multiple, this code will think the header
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* is fine, ignore the truncation, and find what it wants. If the file
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* happens to end up an exact page multiple, this code will write a nul
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* over the final "\n", then be unable to find end_rcs_header, and complain
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* that the file has "no desc line". Who cares ...
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*/
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if ( (sbuf.st_size % pagesize) == 0 )
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buf[sbuf.st_size-1] = '\0';
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if ((end_rcs_header = strstr (buf, "\ndesc\n")) == NULL)
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{ warn ("no desc line:", filename); goto fail1; }
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p = buf + sizeof("head")-1;
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p = skipblanks (p); { if (check (p, "invalid head line:")) goto fail1; }
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q = strchr (p, ';'); { if (check (q, "invalid head format:")) goto fail1; }
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revlen = q - p;
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revp = strndup (p, revlen);
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p = strstr (p, "\nlocks"); { if (check (p, "no locks:")) goto fail2; }
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p += sizeof("\nlocks")-1;
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p = skipblanks (p); { if (check (p, "invalid locks:")) goto fail2; }
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q = strchr (p, ';'); { if (check (q, "invalid locks format:")) goto fail2; }
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lockp = strndup (p, q - p);
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if ((revbuf = malloc(sizeof("\n") + revlen + sizeof("\ndate"))) == NULL)
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error ("no memory");
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strcpy (revbuf, "\n");
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strcat (revbuf, revp);
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strcat (revbuf, "\ndate");
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p = strstr (p, revbuf); { if (check (p, "no rev description:")) goto fail3; }
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p += strlen (revbuf);
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p = skipblanks (p); { if (check (p, "invalid rev desc:")) goto fail3; }
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q = strchr (p, ';'); { if (check (q, "no rev desc colon:")) goto fail3; }
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datep = strndup (p, q - p);
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p = skipblanks (q+1);
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if (strncmp (p, "author", sizeof("author")-1) != 0)
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{ warn ("no desc author", filename); goto fail4; }
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p += sizeof ("author")-1;
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p = skipblanks (p); { if (check (p, "no author:")) goto fail4; }
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q = strchr (p, ';'); { if (check (q, "no author colon:")) goto fail4; }
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authp = strndup (p, q - p);
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goto finish;
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fail1:
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revp = strdup("");
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fail2:
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lockp = strdup("");
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fail3:
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datep = strdup("");
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fail4:
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authp = strdup("");
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finish:
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*revpp = revp;
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*lockpp = lockp;
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*datepp = datep;
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*authpp = authp;
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if (revbuf != NULL)
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free ((void *)revbuf);
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if (buf != (char *)MAP_FAILED) {
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if (munmap (buf, sbuf.st_size) < 0)
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error ("munmap");
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}
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if (fd >= 0)
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close (fd);
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}
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