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Adds verbosity to output, fix
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just-containers/s6-overlay#353

* fix some syscalls were incorrectly checking the return code.
* print out the kind of file being extracted and the actual, on-disk
  path
* remove leading dots and slashes from file names on extraction
* replace utime with lutimes syscall for symlinks
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@jprjr
jprjr committed Nov 23, 2021
1 parent 9712878 commit b310cd4
Showing 1 changed file with 90 additions and 35 deletions.
125 changes: 90 additions & 35 deletions src/justc_installer/main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -5,11 +5,12 @@
#include <skalibs/djbunix.h>
#include <unistd.h>
#include <utime.h>
#include <sys/time.h>
#include <sys/stat.h>

#include "payload.h"
#include "tar.h"


EXTLD(payload_tar)

static stralloc root = STRALLOC_ZERO;
Expand All @@ -28,54 +29,75 @@ static inline size_t blocks(size_t len) {
return blocks;
}

static void build_filename(justc_tar *header, int flush) {
static void build_filename(justc_tar *header) {
size_t len = 0;
char* s = 0;
if(longname) {
longname = 0;
} else {
stralloc_copy(&cur,&root);
if(strlen(header->filename_prefix)) {
stralloc_cats(&cur,header->filename_prefix);
len = strlen(header->filename_prefix);
if(len) {
/* strip leading ./ */
s = header->filename_prefix;
while((*s == '.' || *s == '/') && len) {
s++;
len--;
}
stralloc_catb(&cur,s,len);
stralloc_append(&cur,'/');
}
stralloc_cats(&cur,header->filename);
len = strlen(header->filename);
s = header->filename;
while((*s == '.' || *s == '/') && len) {
s++;
len--;
}
stralloc_catb(&cur,s,len);
/* remove any final / */
while(cur.s[cur.len-1] == '/') {
cur.len--;
}
stralloc_0(&cur);
}

buffer_puts(buffer_1,&cur.s[root.len]);
if(flush) buffer_putsflush(buffer_1,"\n");
}

static int extract_file(justc_tar *header, const unsigned char *s) {
int fd;
struct utimbuf utim;
struct stat st;

build_filename(header,1);
build_filename(header);

buffer_puts(buffer_1,"[file] ");
buffer_puts(buffer_1,cur.s);
buffer_putsflush(buffer_1,"\n");

fd = open_create(cur.s);
if(fd == -1) {
strerr_warn3sys("unable to create ",cur.s,": ");
strerr_warn3sys("(extract_file) unable to create ",cur.s,": ");
return 1;
}
ndelay_off(fd);
if(fd_write(fd,(const char *)s,header->size) != (ssize_t)header->size) {
strerr_warn3sys("unable to write ",cur.s,": ");
strerr_warn3sys("(extract_file) unable to write ",cur.s,": ");
return 1;
}
if(fd_chown(fd,header->uid,header->gid) == -1) {
strerr_warn3sys("unable to chown ",cur.s,": ");
strerr_warn3sys("(extract_file) unable to chown ",cur.s,": ");
}
if(fd_chmod(fd,header->mode) == -1) {
strerr_warn3sys("unable to chmod ",cur.s,": ");
strerr_warn3sys("(extract_file) unable to chmod ",cur.s,": ");
}
if(fstat(fd,&st) == -1) {
strerr_warn3sys("unable to fstat ",cur.s,": ");
strerr_warn3sys("(extract_file) unable to fstat ",cur.s,": ");
}
fd_close(fd);

utim.actime = st.st_atime;
utim.modtime = header->mtime;
if(utime(cur.s, &utim) < 0) {
strerr_warn3sys("unable to utime ",cur.s,": ");
strerr_warn3sys("(extract_file) unable to utime ",cur.s,": ");
}

return 0;
Expand All @@ -84,53 +106,61 @@ static int extract_file(justc_tar *header, const unsigned char *s) {
static int extract_symlink(justc_tar *header, const unsigned char *s) {
stralloc t = STRALLOC_ZERO;
struct stat st;
struct utimbuf utim;
struct timeval lutim[2];
(void)s;

build_filename(header,0);
buffer_puts(buffer_1,"[symlink] ");
build_filename(header);
buffer_puts(buffer_1,cur.s);
buffer_puts(buffer_1," -> ");
if(longlink) {
longlink = 0;
} else {
stralloc_copys(&linkname,header->linked);
stralloc_0(&linkname);
}
buffer_puts(buffer_1,linkname.s);
buffer_putsflush(buffer_1,"\n");

if(strcmp(linkname.s,"/bin/execlineb") == 0) {
/* check if destination /bin is a symlink, do not write out if true */
stralloc_copy(&t,&root);
stralloc_cats(&t,"bin");
stralloc_0(&t);
if(lstat(t.s,&st) == -1) {
strerr_warn3sys("unable to lstat ",t.s,": ");
strerr_warn3sys("(extract_symlink) unable to lstat ",t.s,": ");
return 1;
}
if(S_ISLNK(st.st_mode)) return 0;
}

if(lstat(cur.s,&st) != -1) {
if(unlink(cur.s) == -1) {
strerr_warn3sys("unable to unlink ",cur.s,": ");
strerr_warn3sys("(extract_symlink) unable to unlink ",cur.s,": ");
return 1;
}
}

if(symlink(linkname.s,cur.s) == -1) {
strerr_warn3sys("unable to symlink ",cur.s,": ");
strerr_warn3sys("(extract_symlink) unable to symlink ",cur.s,": ");
return 1;
}

if(lchown(cur.s,header->uid,header->gid) == -1) {
strerr_warn3sys("unable to lchown ",cur.s,": ");
strerr_warn3sys("(extract_symlink) unable to lchown ",cur.s,": ");
}

if(lstat(cur.s,&st) != -1) {
strerr_warn3sys("unable to lstat ",cur.s,": ");
if(lstat(cur.s,&st) == -1) {
strerr_warn3sys("(extract_symlink) unable to lstat ",cur.s,": ");
}

utim.actime = st.st_atime;
utim.modtime = header->mtime;
if(utime(cur.s, &utim) < 0) {
strerr_warn3sys("unable to utime ",cur.s,": ");
lutim[0].tv_sec = st.st_atime;
lutim[1].tv_sec = header->mtime;

lutim[0].tv_usec = 0;
lutim[1].tv_usec = 0;
if(lutimes(cur.s, lutim) < 0) {
strerr_warn3sys("(extract_symlink) unable to lutimes ",cur.s,": ");
}

return 0;
Expand All @@ -140,38 +170,63 @@ static int extract_dir(justc_tar *header, const unsigned char *s) {
struct stat st;
struct utimbuf utim;
(void)s;
build_filename(header,1);
build_filename(header);

buffer_puts(buffer_1,"[directory] ");
buffer_puts(buffer_1,cur.s);
buffer_putsflush(buffer_1,"\n");

if(lstat(cur.s,&st) == -1) {
if(mkdir(cur.s,header->mode) == -1) {
strerr_warn3sys("unable to mkdir ",cur.s,": ");
strerr_warn3sys("(extract_dir) unable to mkdir ",cur.s,": ");
return 1;
}
if(lchown(cur.s,header->uid,header->gid) == -1) {
strerr_warn3sys("unable to chown ",cur.s,": ");
strerr_warn3sys("(extract_dir) unable to chown ",cur.s,": ");
}
if(stat(cur.s,&st) != -1) {
strerr_warn3sys("unable to stat ",cur.s,": ");
if(stat(cur.s,&st) == -1) {
strerr_warn3sys("(extract_dir) unable to stat ",cur.s,": ");
}
utim.actime = st.st_atime;
utim.modtime = header->mtime;
if(utime(cur.s, &utim) < 0) {
strerr_warn3sys("unable to utime ",cur.s,": ");
strerr_warn3sys("(extract_dir) unable to utime ",cur.s,": ");
}
}

return 0;
}

static int extract_gnulonglink(justc_tar *header, const unsigned char *s) {
stralloc_copyb(&linkname,(const char *)s,header->size);
size_t len = header->size;
while((*s == '.' || *s == '/') && len) {
s++;
len--;
}

stralloc_copyb(&linkname,(const char *)s,len);
/* remove any final / */
while(linkname.s[linkname.len-1] == '/') {
linkname.len--;
}
stralloc_0(&linkname);
longlink = 1;
return 0;
}

static int extract_gnulongname(justc_tar *header, const unsigned char *s) {
size_t len = header->size;
while((*s == '.' || *s == '/') && len) {
s++;
len--;
}
stralloc_copy(&cur,&root);
stralloc_catb(&cur,(const char *)s,header->size);
stralloc_catb(&cur,(const char *)s,len);
/* remove any final / */
while(cur.s[cur.len-1] == '/') {
cur.len--;
}
stralloc_0(&cur);
longname = 1;
return 0;
}
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