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add.c: refactor backup file modification checks

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The previous implementation was overly complex with unnecessary checks
and nested conditionals.  By reordering the tests and changing them to
all be checks for positive hash matches rather than non-matches, we can
collapse several cases and make the process much more linear.  This
removes the need to set hash_orig = "" just to reach some of the checks
and corrects a faulty assumption that files are equivalent when the
hashing process fails.

Signed-off-by: Andrew Gregory <andrew.gregory.8@gmail.com>
Signed-off-by: Allan McRae <allan@archlinux.org>
This commit is contained in:
Andrew Gregory 2013-05-18 19:37:59 -04:00 • committed by Allan McRae
parent 5bcc058d42
commit e5dd8c2ac5
1 changed files with 59 additions and 62 deletions
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121
lib/libalpm/add.c
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@ -273,8 +273,6 @@ static int extract_single_file(alpm_handle_t *handle, struct archive *archive,
/* check newpkg first, so that adding backup files is retroactive */ /* check newpkg first, so that adding backup files is retroactive */
backup = _alpm_needbackup(entryname, newpkg); backup = _alpm_needbackup(entryname, newpkg);
if(backup) { if(backup) {
/* if we force hash_orig to be non-NULL retroactive backup works */
hash_orig = "";
needbackup = 1; needbackup = 1;
} }
@ -332,73 +330,42 @@ static int extract_single_file(alpm_handle_t *handle, struct archive *archive,
_alpm_log(handle, ALPM_LOG_DEBUG, "new: %s\n", hash_pkg); _alpm_log(handle, ALPM_LOG_DEBUG, "new: %s\n", hash_pkg);
_alpm_log(handle, ALPM_LOG_DEBUG, "original: %s\n", hash_orig); _alpm_log(handle, ALPM_LOG_DEBUG, "original: %s\n", hash_orig);
if(!oldpkg) { if(hash_local && hash_pkg && strcmp(hash_local, hash_pkg) == 0) {
if(hash_local && hash_pkg && strcmp(hash_local, hash_pkg) != 0) { /* local and new files are the same, no sense in installing the file
/* looks like we have a local file that has a different hash as the * over itself, regardless of what the original file was */
* file in the package, move it to a .pacorig */ _alpm_log(handle, ALPM_LOG_DEBUG,
char *newpath; "action: leaving existing file in place\n");
size_t newlen = strlen(filename) + 9; unlink(checkfile);
MALLOC(newpath, newlen, } else if(hash_orig && hash_pkg && strcmp(hash_orig, hash_pkg) == 0) {
errors++; handle->pm_errno = ALPM_ERR_MEMORY; goto needbackup_cleanup); /* original and new files are the same, leave the local version alone,
snprintf(newpath, newlen, "%s.pacorig", filename); * including any user changes */
_alpm_log(handle, ALPM_LOG_DEBUG,
/* move the existing file to the "pacorig" */ "action: leaving existing file in place\n");
if(try_rename(handle, filename, newpath)) { unlink(checkfile);
errors++; } else if(hash_orig && hash_local && strcmp(hash_orig, hash_local) == 0) {
errors++; /* installed file has NOT been changed by user,
} else { * update to the new version */
/* rename the file we extracted to the real name */ _alpm_log(handle, ALPM_LOG_DEBUG, "action: installing new file: %s\n",
if(try_rename(handle, checkfile, filename)) { entryname_orig);
errors++; if(try_rename(handle, checkfile, filename)) {
} else { errors++;
_alpm_log(handle, ALPM_LOG_WARNING, _("%s saved as %s\n"), filename, newpath);
alpm_logaction(handle, ALPM_CALLER_PREFIX,
"warning: %s saved as %s\n", filename, newpath);
}
}
free(newpath);
} else {
/* local file is identical to pkg one, so just remove pkg one */
unlink(checkfile);
} }
} else if(hash_orig) { } else {
/* the fun part */ /* none of the three files matched another, unpack the new file alongside
* the local file */
if(hash_local && strcmp(hash_orig, hash_local) == 0) { if(oldpkg) {
/* installed file has NOT been changed by user */
if(hash_pkg && strcmp(hash_orig, hash_pkg) != 0) {
_alpm_log(handle, ALPM_LOG_DEBUG, "action: installing new file: %s\n",
entryname_orig);
if(try_rename(handle, checkfile, filename)) {
errors++;
}
} else {
/* no sense in installing the same file twice, install
* ONLY if the original and package hashes differ */
_alpm_log(handle, ALPM_LOG_DEBUG, "action: leaving existing file in place\n");
unlink(checkfile);
}
} else if(hash_pkg && strcmp(hash_orig, hash_pkg) == 0) {
/* originally installed file and new file are the same - this
* implies the case above failed - i.e. the file was changed by a
* user */
_alpm_log(handle, ALPM_LOG_DEBUG, "action: leaving existing file in place\n");
unlink(checkfile);
} else if(hash_local && hash_pkg && strcmp(hash_local, hash_pkg) == 0) {
/* this would be magical. The above two cases failed, but the
* user changes just so happened to make the new file exactly the
* same as the one in the package... skip it */
_alpm_log(handle, ALPM_LOG_DEBUG, "action: leaving existing file in place\n");
unlink(checkfile);
} else {
char *newpath; char *newpath;
size_t newlen = strlen(filename) + 8; size_t newlen = strlen(filename) + strlen(".pacnew") + 1;
_alpm_log(handle, ALPM_LOG_DEBUG, "action: keeping current file and installing"
_alpm_log(handle, ALPM_LOG_DEBUG,
"action: keeping current file and installing"
" new one with .pacnew ending\n"); " new one with .pacnew ending\n");
MALLOC(newpath, newlen, MALLOC(newpath, newlen,
errors++; handle->pm_errno = ALPM_ERR_MEMORY; goto needbackup_cleanup); errors++; handle->pm_errno = ALPM_ERR_MEMORY; goto needbackup_cleanup);
snprintf(newpath, newlen, "%s.pacnew", filename); snprintf(newpath, newlen, "%s.pacnew", filename);
if(try_rename(handle, checkfile, newpath)) { if(try_rename(handle, checkfile, newpath)) {
errors++; errors++;
} else { } else {
@ -407,6 +374,36 @@ static int extract_single_file(alpm_handle_t *handle, struct archive *archive,
alpm_logaction(handle, ALPM_CALLER_PREFIX, alpm_logaction(handle, ALPM_CALLER_PREFIX,
"warning: %s installed as %s\n", filename, newpath); "warning: %s installed as %s\n", filename, newpath);
} }
free(newpath);
} else {
char *newpath;
size_t newlen = strlen(filename) + strlen(".pacorig") + 1;
_alpm_log(handle, ALPM_LOG_DEBUG,
"action: saving existing file with a .pacorig ending"
" and installing a new one\n");
MALLOC(newpath, newlen,
errors++; handle->pm_errno = ALPM_ERR_MEMORY; goto needbackup_cleanup);
snprintf(newpath, newlen, "%s.pacorig", filename);
/* move the existing file to the "pacorig" */
if(try_rename(handle, filename, newpath)) {
errors++; /* failed rename filename -> filename.pacorig */
errors++; /* failed rename checkfile -> filename */
} else {
/* rename the file we extracted to the real name */
if(try_rename(handle, checkfile, filename)) {
errors++;
} else {
_alpm_log(handle, ALPM_LOG_WARNING,
_("%s saved as %s\n"), filename, newpath);
alpm_logaction(handle, ALPM_CALLER_PREFIX,
"warning: %s saved as %s\n", filename, newpath);
}
}
free(newpath); free(newpath);
} }
} }