FreeCalypso > hg > freecalypso-tools
view rvinterf/etmsync/fsread.c @ 465:003e48f8ebe1
rvinterf/etmsync/fsnew.c: cast 0 to (char *) for execl sentinel
I generally don't use NULL and use plain 0 instead, based on a "NULL
considered harmful" discussion on the classiccmp mailing list many aeons
ago (I couldn't find it, and I reason that it must have been 2005 or
earlier), but a recent complaint by a packager sent me searching, and I
found this:
https://ewontfix.com/11/
While I don't give a @#$% about "modern" systems and code-nazi tools,
I realized that passing a plain 0 as a pointer sentinel in execl is wrong
because it will break on systems where pointers are longer than the plain
int type. Again, I don't give a @#$% about the abomination of x86_64 and
the like, but if anyone ever manages to port my code to something like a
PDP-11 (16-bit int, 32-bit long and pointers), then passing a plain 0
as a function argument where a pointer is expected most definitely won't
work: if the most natural stack slot and SP alignment unit is 16 bits,
fitting an int, with longs and pointers taking up two such slots, then
the call stack will be totally wrong with a plain 0 passed for a pointer.
Casting the 0 to (char *) ought to be the most kosher solution for the
most retro systems possible.
author | Mychaela Falconia <falcon@freecalypso.org> |
---|---|
date | Mon, 11 Feb 2019 00:00:19 +0000 |
parents | d332fbf5c145 |
children | 74d284add54d |
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/* * Commands for reading the content of a GSM device's file system */ #include <sys/types.h> #include <sys/param.h> #include <sys/stat.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <strings.h> #include <unistd.h> #include "etm.h" #include "ffs.h" #include "tmffs2.h" #include "limits.h" #include "ffslimits.h" #include "localtypes.h" #include "localstruct.h" #include "exitcodes.h" extern char *pathname_for_ffs_child(); void ll_print_line(pathname, stat) char *pathname; struct stat_info *stat; { char readonly; char rlbuf[256]; if (stat->flags & OF_READONLY) readonly = 'r'; else readonly = ' '; switch (stat->type) { case OT_FILE: printf("f%c %7u %s\n", readonly, stat->size, pathname); return; case OT_DIR: printf("d%c %s\n", readonly, pathname); return; case OT_LINK: if (do_readlink_sancheck(pathname, rlbuf)) strcpy(rlbuf, "<invalid>"); printf("l%c %s -> %s\n", readonly, pathname, rlbuf); return; default: printf("?%c %s\n", readonly, pathname); } } do_ls_long(lsarg) char *lsarg; { struct stat_info stat; u_char rdstate[4]; char rdbuf[MAX_FN_COMPONENT+1], childpath[MAX_FULL_PATHNAME+1], *childp; int nument, i, rc; if (validate_ffs_pathname(lsarg) < 0) return(ERROR_USAGE); /* err msg already printed */ rc = do_xlstat(lsarg, &stat); if (rc) return(rc); if (stat.type != OT_DIR) { ll_print_line(lsarg, &stat); return(0); } rc = do_opendir(lsarg, rdstate, &nument); if (rc) return(rc); if (!nument) { printf("<empty dir>\n"); return(0); } childp = pathname_for_ffs_child(lsarg, childpath); if (!childp) { printf("error: non-empty dir at the limit of pathname depth\n"); return(ERROR_TARGET); } for (i = 0; i < nument; i++) { rc = do_readdir(rdstate, rdbuf, MAX_FN_COMPONENT+1); if (rc) return(rc); if (index(rdbuf, '/')) { printf("error: readdir result contains a slash\n"); return(ERROR_TARGET); } strcpy(childp, rdbuf); rc = do_xlstat(childpath, &stat); if (rc) { printf("xlstat failed on %s\n", childpath); return(rc); } ll_print_line(childpath, &stat); } return(0); } cmd_ll(argc, argv) char **argv; { return do_ls_long(argv[1]); } void hexdump_line(offset, buf, len) u_char *buf; { int i, c; printf("%02X: ", offset); for (i = 0; i < 16; i++) { if (i < len) printf("%02X ", buf[i]); else fputs(" ", stdout); if (i == 7 || i == 15) putchar(' '); } for (i = 0; i < len; i++) { c = buf[i]; if (c < ' ' || c > '~') c = '.'; putchar(c); } putchar('\n'); } cmd_hd(argc, argv) char **argv; { u_char databuf[MAX_READ_DATA]; int rc, sz, off, l; rc = do_file_read(argv[1], databuf, MAX_READ_DATA, &sz); if (rc) return(rc); printf("%d bytes read\n", sz); for (off = 0; off < sz; off += 16) { l = sz - off; if (l > 16) l = 16; hexdump_line(off, databuf + off, l); } return(0); } cpout_object(ffspath, hostpath) char *ffspath, *hostpath; { struct stat_info stat; int rc; rc = do_xlstat(ffspath, &stat); if (rc) return(rc); switch (stat.type) { case OT_FILE: return cpout_file(ffspath, hostpath); case OT_DIR: return cpout_dir(ffspath, hostpath); case OT_LINK: printf("skipping FFS symlink %s\n", ffspath); return(0); default: printf("error: stat returned bad objtype for %s\n", ffspath); return(ERROR_TARGET); } } cpout_file(ffspath, hostpath) char *ffspath, *hostpath; { int tfd; FILE *of; u_char buf[MAX_READ_DATA]; int rc, sz; printf("copying %s\n", ffspath); rc = fd_open(ffspath, FFS_O_RDONLY, &tfd); if (rc) return(rc); of = fopen(hostpath, "w"); if (!of) { perror(hostpath); fd_close(tfd); return(ERROR_UNIX); } for (;;) { rc = fd_read(tfd, buf, MAX_READ_DATA, &sz); if (rc) { fd_close(tfd); fclose(of); return(rc); } if (!sz) break; fwrite(buf, 1, sz, of); } fclose(of); return fd_close(tfd); } cpout_dir(ffspath_dir, hostpath_dir) char *ffspath_dir, *hostpath_dir; { u_char rdstate[4]; char rdbuf[MAX_FN_COMPONENT+1], ffspath_child[MAX_FULL_PATHNAME+1]; char *childp; char hostpath_child[MAXPATHLEN]; int nument, i, rc, childerr; printf("dir %s\n", ffspath_dir); rc = host_mkdir(hostpath_dir); if (rc) return(rc); rc = do_opendir(ffspath_dir, rdstate, &nument); if (rc) return(rc); if (!nument) return(0); childp = pathname_for_ffs_child(ffspath_dir, ffspath_child); if (!childp) { printf("error: non-empty dir at the limit of pathname depth\n"); return(ERROR_TARGET); } childerr = 0; for (i = 0; i < nument; i++) { rc = do_readdir(rdstate, rdbuf, MAX_FN_COMPONENT+1); if (rc) return(rc); if (index(rdbuf, '/')) { printf("error: readdir result contains a slash\n"); return(ERROR_TARGET); } strcpy(childp, rdbuf); if (rdbuf[0] == '.') { printf("skipping %s\n", ffspath_child); continue; } if (strlen(hostpath_dir) + strlen(rdbuf) + 2 > sizeof hostpath_child) { fprintf(stderr, "error: host side pathname buffer overflow\n"); return(ERROR_UNIX); } sprintf(hostpath_child, "%s/%s", hostpath_dir, rdbuf); rc = cpout_object(ffspath_child, hostpath_child); if (rc && rc != ERROR_TARGET) return(rc); if (rc) childerr = rc; } return(childerr); } cmd_cpout(argc, argv) char **argv; { if (validate_ffs_pathname(argv[1]) < 0) return(ERROR_USAGE); /* err msg already printed */ return cpout_object(argv[1], argv[2]); } cmd_cpout_file(argc, argv) char **argv; { return cpout_file(argv[1], argv[2]); }