summaryrefslogtreecommitdiffstats
path: root/util/subst.c
diff options
context:
space:
mode:
Diffstat (limited to 'util/subst.c')
-rw-r--r--util/subst.c468
1 files changed, 468 insertions, 0 deletions
diff --git a/util/subst.c b/util/subst.c
new file mode 100644
index 0000000..be2a0dd
--- /dev/null
+++ b/util/subst.c
@@ -0,0 +1,468 @@
+/*
+ * subst.c --- substitution program
+ *
+ * Subst is used as a quickie program to do @ substitutions
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#else
+#define HAVE_SYS_STAT_H
+#define HAVE_SYS_TIME_H
+#endif
+#include <stdio.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <ctype.h>
+#ifdef HAVE_SYS_TIME_H
+#include <sys/time.h>
+#endif
+#ifdef HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+#ifdef HAVE_SYS_STAT_H
+#include <sys/stat.h>
+#endif
+#include <fcntl.h>
+#include <time.h>
+#include <utime.h>
+#ifdef HAVE_SYS_TIME_H
+#include <sys/time.h>
+#endif
+
+#ifdef HAVE_GETOPT_H
+#include <getopt.h>
+#else
+extern char *optarg;
+extern int optind;
+#endif
+
+
+struct subst_entry {
+ char *name;
+ char *value;
+ struct subst_entry *next;
+};
+
+static struct subst_entry *subst_table = 0;
+
+static int add_subst(char *name, char *value)
+{
+ struct subst_entry *ent = 0;
+
+ ent = (struct subst_entry *) malloc(sizeof(struct subst_entry));
+ if (!ent)
+ goto fail;
+ ent->name = (char *) malloc(strlen(name)+1);
+ if (!ent->name)
+ goto fail;
+ ent->value = (char *) malloc(strlen(value)+1);
+ if (!ent->value)
+ goto fail;
+ strcpy(ent->name, name);
+ strcpy(ent->value, value);
+ ent->next = subst_table;
+ subst_table = ent;
+ return 0;
+fail:
+ if (ent) {
+ free(ent->name);
+ free(ent);
+ }
+ return ENOMEM;
+}
+
+static struct subst_entry *fetch_subst_entry(char *name)
+{
+ struct subst_entry *ent;
+
+ for (ent = subst_table; ent; ent = ent->next) {
+ if (strcmp(name, ent->name) == 0)
+ break;
+ }
+ return ent;
+}
+
+/*
+ * Given the starting and ending position of the replacement name,
+ * check to see if it is valid, and pull it out if it is.
+ */
+static char *get_subst_symbol(const char *begin, size_t len, char prefix)
+{
+ static char replace_name[128];
+ char *cp, *start;
+
+ start = replace_name;
+ if (prefix)
+ *start++ = prefix;
+
+ if (len > sizeof(replace_name)-2)
+ return NULL;
+ memcpy(start, begin, len);
+ start[len] = 0;
+
+ /*
+ * The substitution variable must all be in the of [0-9A-Za-z_].
+ * If it isn't, this must be an invalid symbol name.
+ */
+ for (cp = start; *cp; cp++) {
+ if (!(*cp >= 'a' && *cp <= 'z') &&
+ !(*cp >= 'A' && *cp <= 'Z') &&
+ !(*cp >= '0' && *cp <= '9') &&
+ !(*cp == '_'))
+ return NULL;
+ }
+ return (replace_name);
+}
+
+static void replace_string(char *begin, char *end, char *newstr)
+{
+ int replace_len, len;
+
+ replace_len = strlen(newstr);
+ len = end - begin;
+ if (replace_len == 0)
+ memmove(begin, end+1, strlen(end)+1);
+ else if (replace_len != len+1)
+ memmove(end+(replace_len-len-1), end,
+ strlen(end)+1);
+ memcpy(begin, newstr, replace_len);
+}
+
+static void substitute_line(char *line)
+{
+ char *ptr, *name_ptr, *end_ptr;
+ struct subst_entry *ent;
+ char *replace_name;
+ size_t len;
+
+ /*
+ * Expand all @FOO@ substitutions
+ */
+ ptr = line;
+ while (ptr) {
+ name_ptr = strchr(ptr, '@');
+ if (!name_ptr)
+ break; /* No more */
+ if (*(++name_ptr) == '@') {
+ /*
+ * Handle tytso@@mit.edu --> tytso@mit.edu
+ */
+ memmove(name_ptr-1, name_ptr, strlen(name_ptr)+1);
+ ptr = name_ptr+1;
+ continue;
+ }
+ end_ptr = strchr(name_ptr, '@');
+ if (!end_ptr)
+ break;
+ len = end_ptr - name_ptr;
+ replace_name = get_subst_symbol(name_ptr, len, 0);
+ if (!replace_name) {
+ ptr = name_ptr;
+ continue;
+ }
+ ent = fetch_subst_entry(replace_name);
+ if (!ent) {
+ fprintf(stderr, "Unfound expansion: '%s'\n",
+ replace_name);
+ ptr = end_ptr + 1;
+ continue;
+ }
+#if 0
+ fprintf(stderr, "Replace name = '%s' with '%s'\n",
+ replace_name, ent->value);
+#endif
+ ptr = name_ptr-1;
+ replace_string(ptr, end_ptr, ent->value);
+ if ((ent->value[0] == '@') &&
+ (strlen(replace_name) == strlen(ent->value)-2) &&
+ !strncmp(replace_name, ent->value+1,
+ strlen(ent->value)-2))
+ /* avoid an infinite loop */
+ ptr += strlen(ent->value);
+ }
+ /*
+ * Now do a second pass to expand ${FOO}
+ */
+ ptr = line;
+ while (ptr) {
+ name_ptr = strchr(ptr, '$');
+ if (!name_ptr)
+ break; /* No more */
+ if (*(++name_ptr) != '{') {
+ ptr = name_ptr;
+ continue;
+ }
+ name_ptr++;
+ end_ptr = strchr(name_ptr, '}');
+ if (!end_ptr)
+ break;
+ len = end_ptr - name_ptr;
+ replace_name = get_subst_symbol(name_ptr, len, '$');
+ if (!replace_name) {
+ ptr = name_ptr;
+ continue;
+ }
+ ent = fetch_subst_entry(replace_name);
+ if (!ent) {
+ ptr = end_ptr + 1;
+ continue;
+ }
+#if 0
+ fprintf(stderr, "Replace name = '%s' with '%s'\n",
+ replace_name, ent->value);
+#endif
+ ptr = name_ptr-2;
+ replace_string(ptr, end_ptr, ent->value);
+ }
+}
+
+static void parse_config_file(FILE *f)
+{
+ char line[2048];
+ char *cp, *ptr;
+
+ while (!feof(f)) {
+ memset(line, 0, sizeof(line));
+ if (fgets(line, sizeof(line), f) == NULL)
+ break;
+ /*
+ * Strip newlines and comments.
+ */
+ cp = strchr(line, '\n');
+ if (cp)
+ *cp = 0;
+ cp = strchr(line, '#');
+ if (cp)
+ *cp = 0;
+ /*
+ * Skip trailing and leading whitespace
+ */
+ for (cp = line + strlen(line) - 1; cp >= line; cp--) {
+ if (*cp == ' ' || *cp == '\t')
+ *cp = 0;
+ else
+ break;
+ }
+ cp = line;
+ while (*cp && isspace(*cp))
+ cp++;
+ ptr = cp;
+ /*
+ * Skip empty lines
+ */
+ if (*ptr == 0)
+ continue;
+ /*
+ * Ignore future extensions
+ */
+ if (*ptr == '@')
+ continue;
+ /*
+ * Parse substitutions
+ */
+ for (cp = ptr; *cp; cp++)
+ if (isspace(*cp))
+ break;
+ *cp = 0;
+ for (cp++; *cp; cp++)
+ if (!isspace(*cp))
+ break;
+#if 0
+ printf("Substitute: '%s' for '%s'\n", ptr, cp ? cp : "<NULL>");
+#endif
+ add_subst(ptr, cp);
+ }
+}
+
+/*
+ * Return 0 if the files are different, 1 if the files are the same.
+ */
+static int compare_file(FILE *old_f, FILE *new_f)
+{
+ char oldbuf[2048], newbuf[2048], *oldcp, *newcp;
+ int retval;
+
+ while (1) {
+ oldcp = fgets(oldbuf, sizeof(oldbuf), old_f);
+ newcp = fgets(newbuf, sizeof(newbuf), new_f);
+ if (!oldcp && !newcp) {
+ retval = 1;
+ break;
+ }
+ if (!oldcp || !newcp || strcmp(oldbuf, newbuf)) {
+ retval = 0;
+ break;
+ }
+ }
+ return retval;
+}
+
+void set_utimes(const char *filename, int fd, const struct timeval times[2])
+{
+#ifdef HAVE_FUTIMES
+ if (futimes(fd, times) < 0)
+ perror("futimes");
+#elif HAVE_UTIMES
+ if (utimes(filename, times) < 0)
+ perror("utimes");
+#else
+ struct utimbuf ut;
+
+ ut.actime = times[0].tv_sec;
+ ut.modtime = times[1].tv_sec;
+ if (utime(filename, &ut) < 0)
+ perror("utime");
+#endif
+}
+
+
+int main(int argc, char **argv)
+{
+ char line[2048];
+ int c;
+ int fd, ofd = -1;
+ FILE *in, *out, *old = NULL;
+ char *outfn = NULL, *newfn = NULL;
+ int verbose = 0;
+ int adjust_timestamp = 0;
+ int got_atime = 0;
+ struct stat stbuf;
+ struct timeval tv[2];
+
+ while ((c = getopt (argc, argv, "f:tv")) != EOF) {
+ switch (c) {
+ case 'f':
+ in = fopen(optarg, "r");
+ if (!in) {
+ perror(optarg);
+ exit(1);
+ }
+ parse_config_file(in);
+ fclose(in);
+ break;
+ case 't':
+ adjust_timestamp++;
+ break;
+ case 'v':
+ verbose++;
+ break;
+ default:
+ fprintf(stderr, "%s: [-f config-file] [file]\n",
+ argv[0]);
+ break;
+ }
+ }
+ if (optind < argc) {
+ in = fopen(argv[optind], "r");
+ if (!in) {
+ perror(argv[optind]);
+ exit(1);
+ }
+ optind++;
+ } else
+ in = stdin;
+
+ if (optind < argc) {
+ outfn = argv[optind];
+ newfn = (char *) malloc(strlen(outfn)+20);
+ if (!newfn) {
+ fprintf(stderr, "Memory error! Exiting.\n");
+ exit(1);
+ }
+ strcpy(newfn, outfn);
+ strcat(newfn, ".new");
+ ofd = open(newfn, O_CREAT|O_TRUNC|O_RDWR, 0644);
+ if (ofd < 0) {
+ perror(newfn);
+ exit(1);
+ }
+ out = fdopen(ofd, "w+");
+ if (!out) {
+ perror("fdopen");
+ exit(1);
+ }
+
+ fd = open(outfn, O_RDONLY);
+ if (fd > 0) {
+ /* save the original atime, if possible */
+ if (fstat(fd, &stbuf) == 0) {
+#if HAVE_STRUCT_STAT_ST_ATIM
+ tv[0].tv_sec = stbuf.st_atim.tv_sec;
+ tv[0].tv_usec = stbuf.st_atim.tv_nsec / 1000;
+#else
+ tv[0].tv_sec = stbuf.st_atime;
+ tv[0].tv_usec = 0;
+#endif
+ got_atime = 1;
+ }
+ old = fdopen(fd, "r");
+ if (!old)
+ close(fd);
+ }
+ } else {
+ out = stdout;
+ outfn = 0;
+ }
+
+ while (!feof(in)) {
+ if (fgets(line, sizeof(line), in) == NULL)
+ break;
+ substitute_line(line);
+ fputs(line, out);
+ }
+ fclose(in);
+ if (outfn) {
+ fflush(out);
+ rewind(out);
+ if (old && compare_file(old, out)) {
+ if (verbose)
+ printf("No change, keeping %s.\n", outfn);
+ if (adjust_timestamp) {
+ if (verbose)
+ printf("Updating modtime for %s\n", outfn);
+ if (gettimeofday(&tv[1], NULL) < 0) {
+ perror("gettimeofday");
+ exit(1);
+ }
+ if (got_atime == 0)
+ tv[0] = tv[1];
+ else if (verbose)
+ printf("Using original atime\n");
+ set_utimes(outfn, fileno(old), tv);
+ }
+#ifndef _WIN32
+ if (ofd >= 0)
+ (void) fchmod(ofd, 0444);
+#endif
+ fclose(out);
+ if (unlink(newfn) < 0)
+ perror("unlink");
+ } else {
+ if (verbose)
+ printf("Creating or replacing %s.\n", outfn);
+#ifndef _WIN32
+ if (ofd >= 0)
+ (void) fchmod(ofd, 0444);
+#endif
+ fclose(out);
+ if (old)
+ fclose(old);
+ old = NULL;
+ if (rename(newfn, outfn) < 0) {
+ perror("rename");
+ exit(1);
+ }
+ }
+ }
+ if (old)
+ fclose(old);
+ if (newfn)
+ free(newfn);
+ return (0);
+}
+
+
generated by cgit v1.2.3 (git 2.39.1) at 2024-05-04 15:33:51 +0000