[flashrom-gerrit] Change in flashrom[master]: Match -c parameter against patterns in chip names

[Ryan O'Leary (Code Review)]

Ryan O'Leary has uploaded this change for review. ( https://review.coreboot.org/c/flashrom/+/37723 )

Change subject: Match -c parameter against patterns in chip names
......................................................................

Match -c parameter against patterns in chip names

This includes patterns such as "EN29GL064H/L", "Am29F002(N)BB" and
"A25LQ032/A25LQ32A".

This was inspired by a breakage in one of my scripts. The script
hard-coded "-c CHIPX". When upstream changed the chip name to
"CHIPX/CHIPY", my script broke. By recognizing this pattern, the -c
parameter is more resilient to these types of changes.

Since an exact match on the whole name takes priority (the current
behavior), this should not break anyone's workflow.

Change-Id: Iae00bb1108f2d5a0c10977cff63f9348b9fc017f
Signed-off-by: Ryan O'Leary 
---
M cli_classic.c
1 file changed, 69 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/flashrom refs/changes/23/37723/1

diff --git a/cli_classic.c b/cli_classic.c
index 73cc417..43aac0b 100644
--- a/cli_classic.c
+++ b/cli_classic.c
@@ -103,6 +103,68 @@
    return 0;
 }

+/*
+ * Return 1 if the chip name matches the pattern, otherwise 0.
+ *
+ * The pattern may be:
+ * 1. A single slash followed by a single character.
+ *    Ex: "EN29GL064H/L" matches "EN29GL064H" and "EN29GL064L".
+ * 2. One character in parens.
+ *    Ex: "Am29F002(N)BB" matches "Am29F002BB" and "Am29F002NBB".
+ *    Ex: "EN29F002(A)(N)B" matches four different chip names.
+ * 3. A slash-separated list.
+ *    Ex: "A25LQ032/A25LQ32A" matches "A25LQ032" and "A25LQ32A".
+ *    Ex: "MX25L12835F/MX25L12845E/MX25L12865E" matches "MX25L12835F", "MX25L12845E" and "MX25L12865E".
+ *
+ * #2 may be nested in #3, for example "W29C010(M)/W29C011A/W29EE011/W29EE012".
+ */
+static int chip_name_match_pattern(const char *pattern, const char *chip) {
+	int plen = strlen(pattern);
+	int clen = strlen(chip);
+
+	if (plen < 3 || clen < 3) {
+		return 0;
+	}
+
+	/* Single slash followed by single character. */
+	if (pattern[plen-2] == '/') {
+		for (int pidx = 0; pidx < plen - 2; pidx++)
+			if (pattern[pidx] == '/')
+				return 0;
+		return plen - 2 == clen &&
+		    strncmp(pattern, chip, plen - 3) == 0 &&
+		    (pattern[plen-1] == chip[clen-1] ||
+		     pattern[plen-3] == chip[clen-1]);
+	}
+
+	int cidx = 0;
+	for (int pidx = 0; pidx < plen; pidx++) {
+		if (pattern[pidx] == '/') {
+			/* Check for termination. */
+			if (cidx == clen)
+				break;
+			cidx = 0; /* Reset. */
+		} else if (pattern[pidx] == '(') {
+			if (pidx + 2 >= plen ||
+			    pattern[pidx+1] == ')' ||
+			    pattern[pidx+1] == '(' ||
+			    pattern[pidx+2] != ')')
+				return 0; /* Invalid pattern. */
+			if (pattern[pidx+1] == chip[cidx])
+				cidx++;
+			pidx += 2;
+		} else if (pattern[pidx] == chip[cidx]) {
+			cidx++;
+		} else {
+			/* Reset to next slash. */
+			while (pidx < plen && pattern[pidx] != '/')
+				pidx++;
+			cidx = 0;
+		}
+	}
+	return cidx == clen;
+}
+
 int main(int argc, char *argv[])
 {
    const struct flashchip *chip = NULL;
@@ -421,15 +483,22 @@
    }
    /* Does a chip with the requested name exist in the flashchips array? */
    if (chip_to_probe) {
+		/* First check for exact match. */
    	for (chip = flashchips; chip && chip->name; chip++)
    		if (!strcmp(chip->name, chip_to_probe))
    			break;
+		/* Failing that, perform a pattern match. */
+		if (!chip || !chip->name)
+			for (chip = flashchips; chip && chip->name; chip++)
+				if (chip_name_match_pattern(chip->name, chip_to_probe))
+					break;
    	if (!chip || !chip->name) {
    		msg_cerr("Error: Unknown chip '%s' specified.\n", chip_to_probe);
    		msg_gerr("Run flashrom -L to view the hardware supported in this flashrom version.\n");
    		ret = 1;
    		goto out;
    	}
+		msg_gdbg("Using chip "%s".\n", chip->name);
    	/* Keep chip around for later usage in case a forced read is requested. */
    }